1
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Zhang Q, Halle JL, Counts BR, Pi M, Carson JA. mTORC1 and BMP-Smad1/5 regulation of serum-stimulated myotube hypertrophy: a role for autophagy. Am J Physiol Cell Physiol 2024; 327:C124-C139. [PMID: 38766767 DOI: 10.1152/ajpcell.00237.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 05/14/2024] [Accepted: 05/14/2024] [Indexed: 05/22/2024]
Abstract
Protein synthesis regulation is critical for skeletal muscle hypertrophy, yet other established cellular processes are necessary for growth-related cellular remodeling. Autophagy has a well-acknowledged role in muscle quality control, but evidence for its role in myofiber hypertrophy remains equivocal. Both mammalian target of rapamycin complex I (mTORC1) and bone morphogenetic protein (BMP)-Smad1/5 (Sma and Mad proteins from Caenorhabditis elegans and Drosophila, respectively) signaling are reported regulators of myofiber hypertrophy; however, gaps remain in our understanding of how this regulation is integrated with growth processes and autophagy regulation. Therefore, we investigated the mTORC1 and Smad1/5 regulation of protein synthesis and autophagy flux during serum-stimulated myotube growth. Chronic serum stimulation experiments were performed on day 5 differentiated C2C12 myotubes incubated in differentiation medium [2% horse serum (HS)] or growth medium [5% fetal bovine serum (FBS)] for 48 h. Rapamycin or LDN193189 was dosed for 48 h to inhibit mTORC1 and BMP-Smad1/5 signaling, respectively. Acute serum stimulation was examined in day 7 differentiated myotubes. Protein synthesis was measured by puromycin incorporation. Bafilomycin A1 and immunoblotting for LC3B were used to assess autophagy flux. Chronic serum stimulation increased myotube diameter 22%, total protein 21%, total RNA 100%, and Smad1/5 phosphorylation 404% and suppressed autophagy flux. Rapamycin, but not LDN193189, blocked serum-induced myotube hypertrophy and the increase in total RNA. Acute serum stimulation increased protein synthesis 111%, Smad1/5 phosphorylation 559%, and rpS6 phosphorylation 117% and suppressed autophagy flux. Rapamycin increased autophagy flux during acute serum stimulation. These results provide evidence for mTORC1, but not BMP-Smad1/5, signaling being required for serum-induced myotube hypertrophy and autophagy flux by measuring LC3BII/I expression. Further investigation is warranted to examine the role of autophagy flux in myotube hypertrophy.NEW & NOTEWORTHY The present study demonstrates that myotube hypertrophy caused by chronic serum stimulation requires mammalian target of rapamycin complex 1 (mTORC1) signaling but not bone morphogenetic protein (BMP)-Smad1/5 signaling. The suppression of autophagy flux was associated with serum-induced myotube hypertrophy and mTORC1 regulation of autophagy flux by measuring LC3BII/I expression. Rapamycin is widely investigated for beneficial effects in aging skeletal muscle and sarcopenia; our results provide evidence that rapamycin can regulate autophagy-related signaling during myotube growth, which could benefit skeletal muscle functional and metabolic health.
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Affiliation(s)
- Quan Zhang
- Integrative Muscle Biology Laboratory, Division of Rehabilitation Sciences, College of Health ProfessionsUniversity of Tennessee Health Science Center, Memphis, Tennessee, United States
| | - Jessica L Halle
- Integrative Muscle Biology Laboratory, Division of Rehabilitation Sciences, College of Health ProfessionsUniversity of Tennessee Health Science Center, Memphis, Tennessee, United States
| | - Brittany R Counts
- Integrative Muscle Biology Laboratory, Division of Rehabilitation Sciences, College of Health ProfessionsUniversity of Tennessee Health Science Center, Memphis, Tennessee, United States
| | - Min Pi
- Department of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee, United States
| | - James A Carson
- Huffines Institute for Sports Medicine & Human Performance, Department of Kinesiology & Sports Management , Texas A&M University, College Station, Texas, United States
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Brown A, Parise G, Thomas ACQ, Ng SY, McGlory C, Phillips SM, Kumbhare D, Joanisse S. Low baseline ribosome-related gene expression and resistance training-induced declines in ribosome-related gene expression are associated with skeletal muscle hypertrophy in young men and women. J Cell Physiol 2024; 239:e31182. [PMID: 38214457 DOI: 10.1002/jcp.31182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 12/04/2023] [Accepted: 12/12/2023] [Indexed: 01/13/2024]
Abstract
Ribosomes are essential cellular machinery for protein synthesis. It is hypothesised that ribosome content supports muscle growth and that individuals with more ribosomes have greater increases in muscle size following resistance training (RT). Aerobic conditioning (AC) also elicits distinct physiological adaptations; however, no measures of ribosome content following AC have been conducted. We used ribosome-related gene expression as a proxy measure for ribosome content and hypothesised that AC and RT would increase ribosome-related gene expression. Fourteen young men and women performed 6 weeks of single-legged AC followed by 10 weeks of double-legged RT. Muscle biopsies were taken following AC and following RT in the aerobically conditioned (AC+RT) and unconditioned (RT) legs. No differences in regulatory genes (Ubf, Cyclin D1, Tif-1a and Polr-1b) involved in ribosomal biogenesis or ribosomal RNA (45S, 5.8S, 18S and 28S rRNAs) expression were observed following AC and RT, except for c-Myc (RT > AC+RT) and 5S rRNA (RT < AC+RT at pre-RT) with 18S external transcribed spacer and 5.8S internal transcribed spacer expression decreasing from pre-RT to post-RT in the RT leg only. When divided for change in leg-lean soft tissue mass (ΔLLSTM) following RT, legs with the greatest ΔLLSTM had lower expression in 11/13 measured ribosome-related genes before RT and decreased expression in 9/13 genes following RT. These results indicate that AC and RT did not increase ribosome-related gene expression. Contrary to previous research, the greatest increase in muscle mass was associated with lower changes in ribosome-related gene expression over the course of the 10-week training programme. This may point to the importance of translational efficiency rather than translational capacity (i.e. ribosome content) in mediating long-term exercise-induced adaptations in skeletal muscle.
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Affiliation(s)
- Alex Brown
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Gianni Parise
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Aaron C Q Thomas
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Sean Y Ng
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Chris McGlory
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
- Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | - Stuart M Phillips
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Dinesh Kumbhare
- Toronto Rehabilitation Institute, University of Toronto, Toronto, Ontario, Canada
| | - Sophie Joanisse
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
- Institute of Sport, Manchester Metropolitan University, Manchester, UK
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research, Nottingha, UK
- School of Life Sciences, University of Nottingham, Nottingham, UK
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3
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Laskin GR, Cabrera AR, Greene NP, Tomko RJ, Vied C, Gordon BS. The mechanosensitive gene arrestin domain containing 2 regulates myotube diameter with direct implications for disuse atrophy with aging. Am J Physiol Cell Physiol 2024; 326:C768-C783. [PMID: 38314723 PMCID: PMC11193484 DOI: 10.1152/ajpcell.00444.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 01/08/2024] [Accepted: 01/22/2024] [Indexed: 02/07/2024]
Abstract
Arrestin domain containing 2 and 3 (Arrdc2/3) are genes whose mRNA contents are decreased in young skeletal muscle following mechanical overload. Arrdc3 is linked to the regulation of signaling pathways in nonmuscle cells that could influence skeletal muscle size. Despite a similar amino acid sequence, Arrdc2 function remains undefined. The purpose of this study was to further explore the relationship of Arrdc2/Arrdc3 expression with changes in mechanical load in young and aged muscle and define the effect of Arrdc2/3 expression on C2C12 myotube diameter. In young and aged mice, mechanical load was decreased using hindlimb suspension whereas mechanical load was increased by reloading previously unloaded muscle or inducing high-force contractions. Arrdc2 and Arrdc3 mRNAs were overexpressed in C2C12 myotubes using adenoviruses. Myotube diameter was determined 48-h posttransfection, and RNA sequencing was performed on those samples. Arrdc2 and Arrdc3 mRNA content was higher in the unloaded muscle within 1 day of disuse and remained higher up through 10 days. The induction of Arrdc2 mRNA was more pronounced in aged muscle than young muscle in response to unloading. Reloading previously unloaded muscle of young and aged mice restored Arrdc2 and Arrdc3 levels to ambulatory levels. Increasing mechanical load beyond normal ambulatory levels lowered Arrdc2 mRNA, but not Arrdc3 mRNA, in young and aged muscle. Arrdc2 overexpression only was sufficient to lower myotube diameter in C2C12 cells in part by altering the transcriptome favoring muscle atrophy. These data are consistent with Arrdc2 contributing to disuse atrophy, particularly in aged muscle.NEW & NOTEWORTHY We establish Arrdc2 as a novel mechanosensitive gene highly induced in response to mechanical unloading, particularly in aged muscle. Arrdc2 induction in C2C12 myotubes is sufficient to produce thinner myotubes and a transcriptional landscape consistent with muscle atrophy and disuse.
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Affiliation(s)
- Grant R Laskin
- Department of of Health, Nutrition, and Food Sciences, Florida State University, Tallahassee, Florida, United States
| | - Ana Regina Cabrera
- Department of Health, Human Performance and Recreation, Cachexia Research Laboratory, Exercise Science Research Center, University of Arkansas, Fayetteville, Arkansas, United States
| | - Nicholas P Greene
- Department of Health, Human Performance and Recreation, Cachexia Research Laboratory, Exercise Science Research Center, University of Arkansas, Fayetteville, Arkansas, United States
| | - Robert J Tomko
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida, United States
| | - Cynthia Vied
- Translational Science Laboratory, Florida State University College of Medicine, Tallahassee, Florida, United States
| | - Bradley S Gordon
- Department of of Health, Nutrition, and Food Sciences, Florida State University, Tallahassee, Florida, United States
- Institute of Sports Sciences and Medicine, Florida State University, Tallahassee, Florida, United States
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Davids CJ, Roberts LA, Bjørnsen T, Peake JM, Coombes JS, Raastad T. Where Does Blood Flow Restriction Fit in the Toolbox of Athletic Development? A Narrative Review of the Proposed Mechanisms and Potential Applications. Sports Med 2023; 53:2077-2093. [PMID: 37578669 PMCID: PMC10587223 DOI: 10.1007/s40279-023-01900-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/24/2023] [Indexed: 08/15/2023]
Abstract
Blood flow-restricted exercise is currently used as a low-intensity time-efficient approach to reap many of the benefits of typical high-intensity training. Evidence continues to lend support to the notion that even highly trained individuals, such as athletes, still benefit from this mode of training. Both resistance and endurance exercise may be combined with blood flow restriction to provide a spectrum of adaptations in skeletal muscle, spanning from myofibrillar to mitochondrial adjustments. Such diverse adaptations would benefit both muscular strength and endurance qualities concurrently, which are demanded in athletic performance, most notably in team sports. Moreover, recent work indicates that when traditional high-load resistance training is supplemented with low-load, blood flow-restricted exercise, either in the same session or as a separate training block in a periodised programme, a synergistic and complementary effect on training adaptations may occur. Transient reductions in mechanical loading of tissues afforded by low-load, blood flow-restricted exercise may also serve a purpose during de-loading, tapering or rehabilitation of musculoskeletal injury. This narrative review aims to expand on the current scientific and practical understanding of how blood flow restriction methods may be applied by coaches and practitioners to enhance current athletic development models.
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Affiliation(s)
- Charlie J Davids
- Sport, Performance, and Nutrition Research Group, School of Allied Health, Human Services and Sport, La Trobe University, Melbourne, Australia.
- School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, QLD, Australia.
- Sport Performance Innovation and Knowledge Excellence (SPIKE), Queensland Academy of Sport, Brisbane, QLD, Australia.
| | - Llion A Roberts
- School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, QLD, Australia
- Sport Performance Innovation and Knowledge Excellence (SPIKE), Queensland Academy of Sport, Brisbane, QLD, Australia
- School of Health Sciences and Social Work, Griffith University, Gold Coast, QLD, Australia
| | - Thomas Bjørnsen
- Department of Sport Science and Physical Education, University of Agder, Kristiansand, Norway
- Norwegian Olympic and Paralympic Committee and Confederation of Sports, Oslo, Norway
| | - Jonathan M Peake
- Sport Performance Innovation and Knowledge Excellence (SPIKE), Queensland Academy of Sport, Brisbane, QLD, Australia
- School of Biomedical Science, Queensland University of Technology, Brisbane, QLD, Australia
| | - Jeff S Coombes
- School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Truls Raastad
- Norwegian Olympic and Paralympic Committee and Confederation of Sports, Oslo, Norway
- Department of Physical Performance, Norwegian School of Sport Science, Oslo, Norway
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5
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Roberts MD, McCarthy JJ, Hornberger TA, Phillips SM, Mackey AL, Nader GA, Boppart MD, Kavazis AN, Reidy PT, Ogasawara R, Libardi CA, Ugrinowitsch C, Booth FW, Esser KA. Mechanisms of mechanical overload-induced skeletal muscle hypertrophy: current understanding and future directions. Physiol Rev 2023; 103:2679-2757. [PMID: 37382939 PMCID: PMC10625844 DOI: 10.1152/physrev.00039.2022] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 06/12/2023] [Accepted: 06/21/2023] [Indexed: 06/30/2023] Open
Abstract
Mechanisms underlying mechanical overload-induced skeletal muscle hypertrophy have been extensively researched since the landmark report by Morpurgo (1897) of "work-induced hypertrophy" in dogs that were treadmill trained. Much of the preclinical rodent and human resistance training research to date supports that involved mechanisms include enhanced mammalian/mechanistic target of rapamycin complex 1 (mTORC1) signaling, an expansion in translational capacity through ribosome biogenesis, increased satellite cell abundance and myonuclear accretion, and postexercise elevations in muscle protein synthesis rates. However, several lines of past and emerging evidence suggest that additional mechanisms that feed into or are independent of these processes are also involved. This review first provides a historical account of how mechanistic research into skeletal muscle hypertrophy has progressed. A comprehensive list of mechanisms associated with skeletal muscle hypertrophy is then outlined, and areas of disagreement involving these mechanisms are presented. Finally, future research directions involving many of the discussed mechanisms are proposed.
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Affiliation(s)
- Michael D Roberts
- School of Kinesiology, Auburn University, Auburn, Alabama, United States
| | - John J McCarthy
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky, United States
| | - Troy A Hornberger
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin, United States
| | - Stuart M Phillips
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Abigail L Mackey
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery, Copenhagen University Hospital-Bispebjerg and Frederiksberg, and Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Gustavo A Nader
- Department of Kinesiology and Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, United States
| | - Marni D Boppart
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States
| | - Andreas N Kavazis
- School of Kinesiology, Auburn University, Auburn, Alabama, United States
| | - Paul T Reidy
- Department of Kinesiology, Nutrition and Health, Miami University, Oxford, Ohio, United States
| | - Riki Ogasawara
- Healthy Food Science Research Group, Cellular and Molecular Biotechnology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | - Cleiton A Libardi
- MUSCULAB-Laboratory of Neuromuscular Adaptations to Resistance Training, Department of Physical Education, Federal University of São Carlos, São Carlos, Brazil
| | - Carlos Ugrinowitsch
- School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
| | - Frank W Booth
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri, United States
| | - Karyn A Esser
- Department of Physiology and Aging, College of Medicine, University of Florida, Gainesville, Florida, United States
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6
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Lee MK, Ryu H, Van JY, Kim MJ, Jeong HH, Jung WK, Jun JY, Lee B. The Role of Macrophage Populations in Skeletal Muscle Insulin Sensitivity: Current Understanding and Implications. Int J Mol Sci 2023; 24:11467. [PMID: 37511225 PMCID: PMC10380189 DOI: 10.3390/ijms241411467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 07/07/2023] [Accepted: 07/13/2023] [Indexed: 07/30/2023] Open
Abstract
Insulin resistance is a crucial factor in the development of type 2 diabetes mellitus (T2DM) and other metabolic disorders. Skeletal muscle, the body's largest insulin-responsive tissue, plays a significant role in the pathogenesis of T2DM due to defects in insulin signaling. Recently, there has been growing evidence that macrophages, immune cells essential for tissue homeostasis and injury response, also contribute to the development of skeletal muscle insulin resistance. This review aims to summarize the current understanding of the role of macrophages in skeletal muscle insulin resistance. Firstly, it provides an overview of the different macrophage populations present in skeletal muscle and their specific functions in the development of insulin resistance. Secondly, it examines the underlying mechanisms by which macrophages promote or alleviate insulin resistance in skeletal muscle, including inflammation, oxidative stress, and altered metabolism. Lastly, the review discusses potential therapeutic strategies targeting macrophages to improve skeletal muscle insulin sensitivity and metabolic health.
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Affiliation(s)
- Min-Kyeong Lee
- Department of Food Science and Nutrition, Pukyong National University, Busan 48513, Republic of Korea; (M.-K.L.); (H.R.)
| | - Heeyeon Ryu
- Department of Food Science and Nutrition, Pukyong National University, Busan 48513, Republic of Korea; (M.-K.L.); (H.R.)
| | - Ji Yun Van
- Department of Smart Green Technology Engineering, Pukyong National University, Busan 48513, Republic of Korea; (J.Y.V.)
| | - Myeong-Jin Kim
- Department of Food Science and Nutrition, Pukyong National University, Busan 48513, Republic of Korea; (M.-K.L.); (H.R.)
| | - Hyeon Hak Jeong
- Department of Smart Green Technology Engineering, Pukyong National University, Busan 48513, Republic of Korea; (J.Y.V.)
| | - Won-Kyo Jung
- Division of Biomedical Engineering and Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan 48513, Republic of Korea;
| | - Joo Yun Jun
- Neuroscience and Cognitive Science Program, University of Maryland, College Park, MD 20742, USA;
| | - Bonggi Lee
- Department of Food Science and Nutrition, Pukyong National University, Busan 48513, Republic of Korea; (M.-K.L.); (H.R.)
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7
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Cortez NE, Pathak S, Rodriguez Lanzi C, Hong BV, Crone R, Sule R, Wang F, Chen S, Gomes AV, Baar K, Mackenzie GG. A Ketogenic Diet in Combination with Gemcitabine Mitigates Pancreatic Cancer-Associated Cachexia in Male and Female KPC Mice. Int J Mol Sci 2023; 24:10753. [PMID: 37445930 PMCID: PMC10341838 DOI: 10.3390/ijms241310753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 06/20/2023] [Accepted: 06/22/2023] [Indexed: 07/15/2023] Open
Abstract
Cancer-associated cachexia (CAC) is a critical contributor to pancreatic ductal adenocarcinoma (PDAC) mortality. Thus, there is an urgent need for new strategies to mitigate PDAC-associated cachexia; and the exploration of dietary interventions is a critical component. We previously observed that a ketogenic diet (KD) combined with gemcitabine enhances overall survival in the autochthonous LSL-KrasG12D/+; LSL-Trp53 R172H/+; Pdx1-Cre (KPC) mouse model. In this study, we investigated the effect and cellular mechanisms of a KD in combination with gemcitabine on the maintenance of skeletal muscle mass in KPC mice. For this purpose, male and female pancreatic tumor-bearing KPC mice were allocated to a control diet (CD), a KD, a CD + gemcitabine (CG), or a KD + gemcitabine (KG) group. We observed that a KD or a KG-mitigated muscle strength declined over time and presented higher gastrocnemius weights compared CD-fed mice. Mechanistically, we observed sex-dependent effects of KG treatment, including the inhibition of autophagy, and increased phosphorylation levels of eIF2α in KG-treated KPC mice when compared to CG-treated mice. Our data suggest that a KG results in preservation of skeletal muscle mass. Additional research is warranted to explore whether this diet-treatment combination can be clinically effective in combating CAC in PDAC patients.
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Affiliation(s)
- Natalia E. Cortez
- Department of Nutrition, University of California, One Shields Ave., Davis, CA 95616, USA; (N.E.C.); (C.R.L.); (B.V.H.)
| | - Suraj Pathak
- Department of Physiology and Membrane Biology, One Shields Ave., Davis, CA 95616, USA; (S.P.); (R.C.); (R.S.); (A.V.G.); (K.B.)
- Department of Neurobiology, Physiology and Behavior, University of California, One Shields Ave., Davis, CA 95616, USA
| | - Cecilia Rodriguez Lanzi
- Department of Nutrition, University of California, One Shields Ave., Davis, CA 95616, USA; (N.E.C.); (C.R.L.); (B.V.H.)
| | - Brian V. Hong
- Department of Nutrition, University of California, One Shields Ave., Davis, CA 95616, USA; (N.E.C.); (C.R.L.); (B.V.H.)
| | - Ryman Crone
- Department of Physiology and Membrane Biology, One Shields Ave., Davis, CA 95616, USA; (S.P.); (R.C.); (R.S.); (A.V.G.); (K.B.)
- Department of Neurobiology, Physiology and Behavior, University of California, One Shields Ave., Davis, CA 95616, USA
| | - Rasheed Sule
- Department of Physiology and Membrane Biology, One Shields Ave., Davis, CA 95616, USA; (S.P.); (R.C.); (R.S.); (A.V.G.); (K.B.)
- Department of Neurobiology, Physiology and Behavior, University of California, One Shields Ave., Davis, CA 95616, USA
| | - Fangyi Wang
- Department of Animal Science, University of California, One Shields Ave., Davis, CA 95616, USA;
| | - Shuai Chen
- Division of Biostatistics, Department of Public Health Sciences, University of California, One Shields Ave., Davis, CA 95616, USA;
- University of California Davis Comprehensive Cancer Center, Sacramento, CA 95817, USA
| | - Aldrin V. Gomes
- Department of Physiology and Membrane Biology, One Shields Ave., Davis, CA 95616, USA; (S.P.); (R.C.); (R.S.); (A.V.G.); (K.B.)
- Department of Neurobiology, Physiology and Behavior, University of California, One Shields Ave., Davis, CA 95616, USA
| | - Keith Baar
- Department of Physiology and Membrane Biology, One Shields Ave., Davis, CA 95616, USA; (S.P.); (R.C.); (R.S.); (A.V.G.); (K.B.)
- Department of Neurobiology, Physiology and Behavior, University of California, One Shields Ave., Davis, CA 95616, USA
| | - Gerardo G. Mackenzie
- Department of Nutrition, University of California, One Shields Ave., Davis, CA 95616, USA; (N.E.C.); (C.R.L.); (B.V.H.)
- University of California Davis Comprehensive Cancer Center, Sacramento, CA 95817, USA
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8
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Smith MA, Sexton CL, Smith KA, Osburn SC, Godwin JS, Beausejour JP, Ruple BA, Goodlett MD, Edison JL, Fruge AD, Robinson AT, Gladden LB, Young KC, Roberts MD. Molecular predictors of resistance training outcomes in young untrained female adults. J Appl Physiol (1985) 2023; 134:491-507. [PMID: 36633866 PMCID: PMC10190845 DOI: 10.1152/japplphysiol.00605.2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 01/10/2023] [Accepted: 01/10/2023] [Indexed: 01/13/2023] Open
Abstract
We sought to determine if the myofibrillar protein synthetic (MyoPS) response to a naïve resistance exercise (RE) bout, or chronic changes in satellite cell number and muscle ribosome content, were associated with hypertrophic outcomes in females or differed in those who classified as higher (HR) or lower (LR) responders to resistance training (RT). Thirty-four untrained college-aged females (23.4 ± 3.4 kg/m2) completed a 10-wk RT protocol (twice weekly). Body composition and leg imaging assessments, a right leg vastus lateralis biopsy, and strength testing occurred before and following the intervention. A composite score, which included changes in whole body lean/soft tissue mass (LSTM), vastus lateralis (VL) muscle cross-sectional area (mCSA), midthigh mCSA, and deadlift strength, was used to delineate upper and lower HR (n = 8) and LR (n = 8) quartiles. In all participants, training significantly (P < 0.05) increased LSTM, VL mCSA, midthigh mCSA, deadlift strength, mean muscle fiber cross-sectional area, satellite cell abundance, and myonuclear number. Increases in LSTM (P < 0.001), VL mCSA (P < 0.001), midthigh mCSA (P < 0.001), and deadlift strength (P = 0.001) were greater in HR vs. LR. The first-bout 24-hour MyoPS response was similar between HR and LR (P = 0.367). While no significant responder × time interaction existed for muscle total RNA concentrations (i.e., ribosome content) (P = 0.888), satellite cell abundance increased in HR (P = 0.026) but not LR (P = 0.628). Pretraining LSTM (P = 0.010), VL mCSA (P = 0.028), and midthigh mCSA (P < 0.001) were also greater in HR vs. LR. Female participants with an enhanced satellite cell response to RT, and more muscle mass before RT, exhibited favorable resistance training adaptations.NEW & NOTEWORTHY This study continues to delineate muscle biology differences between lower and higher responders to resistance training and is unique in that a female population was interrogated. As has been reported in prior studies, increases in satellite cell numbers are related to positive responses to resistance training. Satellite cell responsivity, rather than changes in muscle ribosome content per milligrams of tissue, may be a more important factor in delineating resistance-training responses in women.
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Affiliation(s)
- Morgan A Smith
- School of Kinesiology, Auburn University, Auburn, Alabama
| | - Casey L Sexton
- School of Kinesiology, Auburn University, Auburn, Alabama
| | - Kristen A Smith
- Department of Nutrition, Dietetics and Hospitality Management, Auburn University, Auburn, Alabama
| | | | | | | | | | - Michael D Goodlett
- Athletics Department, Auburn University, Auburn, Alabama
- Edward Via College of Osteopathic Medicine, Auburn, Alabama
| | - Joseph L Edison
- Athletics Department, Auburn University, Auburn, Alabama
- Edward Via College of Osteopathic Medicine, Auburn, Alabama
| | - Andrew D Fruge
- Department of Nutrition, Dietetics and Hospitality Management, Auburn University, Auburn, Alabama
- College of Nursing, Auburn University, Auburn, Alabama
| | | | | | - Kaelin C Young
- School of Kinesiology, Auburn University, Auburn, Alabama
- Edward Via College of Osteopathic Medicine, Auburn, Alabama
| | - Michael D Roberts
- School of Kinesiology, Auburn University, Auburn, Alabama
- Edward Via College of Osteopathic Medicine, Auburn, Alabama
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9
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Jaitovich A. Impaired regenerative capacity contributes to skeletal muscle dysfunction in chronic obstructive pulmonary disease. Am J Physiol Cell Physiol 2022; 323:C974-C989. [PMID: 35993519 PMCID: PMC9484993 DOI: 10.1152/ajpcell.00292.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 08/16/2022] [Accepted: 08/16/2022] [Indexed: 01/18/2023]
Abstract
Locomotor skeletal muscle dysfunction is a relevant comorbidity of chronic obstructive pulmonary disease (COPD) and is strongly associated with worse clinical outcomes including higher mortality. Over the last decades, a large body of literature helped characterize the process, defining the disruptive muscle phenotype caused by COPD that involves reduction in muscle mass, force-generation capacity, fatigue-tolerance, and regenerative potential following injury. A major limitation in the field has been the scarcity of well-calibrated animal models to conduct mechanistic research based on loss- and gain-of-function studies. This article provides an overall description of the process, the tools available to mechanistically investigate it, and the potential role of mitochondrially driven metabolic signals on the regulation muscle regeneration after injury in COPD. Finally, a description of future avenues to further expand on the area is proposed based on very recent evidence involving mitochondrial metabolic cues affecting myogenesis.
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Affiliation(s)
- Ariel Jaitovich
- Division of Pulmonary and Critical Care Medicine, Department of Molecular and Cellular Physiology, Albany Medical College, Albany, New York
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10
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Kotani T, Tamura Y, Kouzaki K, Kato H, Isemura M, Nakazato K. Percutaneous electrical stimulation-induced muscle contraction prevents the decrease in ribosome RNA and ribosome protein during pelvic hindlimb suspension. J Appl Physiol (1985) 2022; 133:822-833. [PMID: 36007895 DOI: 10.1152/japplphysiol.00204.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Skeletal muscle unloading leads to muscle atrophy. Ribosome synthesis has been implicated as an important skeletal muscle mass regulator owing to its translational capacity. Muscle unloading induces a reduction in ribosome synthesis and content, with muscle atrophy. Percutaneous electrical muscle stimulation (pEMS)-induced muscle contraction is widely used in clinics to improve muscle mass. However, its efficacy in rescuing the reduction in ribosomal synthesis has not been addressed thus far. We examined the effects of daily pEMS treatment on ribosome synthesis and content during mouse hindlimb unloading. Male C57BL/6J mice were randomly assigned to sedentary (SED) and hindlimb unloading by pelvic suspension (HU) groups. Muscle contraction was triggered by pEMS treatment of the right gastrocnemius muscle of a subset of the HU group (HU+pEMS). Hindlimb unloading for 6 days significantly lowered 28S rRNA, rpL10, and rpS3 expression, which was rescued by daily pEMS treatment. The protein expression of phospho-p70S6K and UBF was significantly higher in the HU+pEMS than in the HU group. The mRNA expression of ribophagy receptor Nufip1 increased in both the HU and HU+pEMS groups. Protein light chain 3 (LC3)-II expression and the LC3-II/LC3-I ratio were increased by HU, but pEMS attenuated this increase. Our findings indicate that during HU, daily pEMS treatment prevents the reduction in the levels of some proteins associated with ribosome synthesis. Additionally, the HU-induced activation of ribosome degradation may be attenuated. These data provide insights into ribosome content regulation and the mechanism of attenuation of muscle atrophy by pEMS treatment during muscle disuse.
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Affiliation(s)
- Takaya Kotani
- Research Institute for Sport Science, Nippon Sport Science University, Tokyo, Japan
| | - Yuki Tamura
- Research Institute for Sport Science, Nippon Sport Science University, Tokyo, Japan.,Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan.,Faculty of Sport Science, Nippon Sport Science University, Tokyo, Japan
| | - Karina Kouzaki
- Research Institute for Sport Science, Nippon Sport Science University, Tokyo, Japan.,Graduate School of Medical and Health Science, Nippon Sport Science University, Tokyo, Japan
| | - Hikaru Kato
- Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
| | - Mako Isemura
- Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan
| | - Koichi Nakazato
- Research Institute for Sport Science, Nippon Sport Science University, Tokyo, Japan.,Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan.,Graduate School of Medical and Health Science, Nippon Sport Science University, Tokyo, Japan.,Faculty of Medical Science, Nippon Sport Science University, Tokyo, Japan
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11
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Hammarström D, Øfsteng SJ, Jacobsen NB, Flobergseter KB, Rønnestad BR, Ellefsen S. Ribosome accumulation during early phase resistance training in humans. Acta Physiol (Oxf) 2022; 235:e13806. [PMID: 35213791 PMCID: PMC9540306 DOI: 10.1111/apha.13806] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 02/04/2022] [Accepted: 02/21/2022] [Indexed: 12/16/2022]
Abstract
Aim To describe ribosome biogenesis during resistance training, its relation to training volume and muscle growth. Methods A training group (n = 11) performed 12 sessions (3‐4 sessions per week) of unilateral knee extension with constant and variable volume (6 and 3‐9 sets per session respectively) allocated to either leg. Ribosome abundance and biogenesis markers were assessed from vastus lateralis biopsies obtained at baseline, 48 hours after sessions 1, 4, 5, 8, 9 and 12, and after eight days of de‐training, and from a control group (n = 8). Muscle thickness was measured before and after the intervention. Results Training led to muscle growth (3.9% over baseline values, 95% CrI: [0.2, 7.5] vs. control) with concomitant increases in total RNA, ribosomal RNA, upstream binding factor (UBF) and ribosomal protein S6 with no differences between volume conditions. Total RNA increased rapidly in response to the first four sessions (8.6% [5.6, 11.7] per session), followed by a plateau and peak values after session 8 (49.5% [34.5, 66.5] above baseline). Total RNA abundance was associated with UBF protein levels (5.0% [0.2, 10.2] per unit UBF), and the rate of increase in total RNA levels predicted hypertrophy (0.3 mm [0.1, 0.4] per %‐point increase in total RNA per session). After de‐training, total RNA decreased (−19.3% [−29.0, −8.1]) without muscle mass changes indicating halted biosynthesis of ribosomes. Conclusion Ribosomes accumulate in the initial phase of resistance training with abundances sensitive to training cessation and associated with UBF protein levels. The average accumulation rate predicts muscle training‐induced hypertrophy.
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Affiliation(s)
- Daniel Hammarström
- Section for Health and Exercise Physiology Department of Public Health and Sport Sciences Inland Norway University of Applied Sciences Lillehammer Norway
- Swedish School of Sport and Health Sciences Stockholm Sweden
| | - Sjur J. Øfsteng
- Section for Health and Exercise Physiology Department of Public Health and Sport Sciences Inland Norway University of Applied Sciences Lillehammer Norway
| | - Nicolai B. Jacobsen
- Section for Health and Exercise Physiology Department of Public Health and Sport Sciences Inland Norway University of Applied Sciences Lillehammer Norway
| | - Krister B. Flobergseter
- Section for Health and Exercise Physiology Department of Public Health and Sport Sciences Inland Norway University of Applied Sciences Lillehammer Norway
| | - Bent R. Rønnestad
- Section for Health and Exercise Physiology Department of Public Health and Sport Sciences Inland Norway University of Applied Sciences Lillehammer Norway
| | - Stian Ellefsen
- Section for Health and Exercise Physiology Department of Public Health and Sport Sciences Inland Norway University of Applied Sciences Lillehammer Norway
- Innlandet Hospital Trust Lillehammer Norway
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12
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Lavin KM, Coen PM, Baptista LC, Bell MB, Drummer D, Harper SA, Lixandrão ME, McAdam JS, O’Bryan SM, Ramos S, Roberts LM, Vega RB, Goodpaster BH, Bamman MM, Buford TW. State of Knowledge on Molecular Adaptations to Exercise in Humans: Historical Perspectives and Future Directions. Compr Physiol 2022; 12:3193-3279. [PMID: 35578962 PMCID: PMC9186317 DOI: 10.1002/cphy.c200033] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
For centuries, regular exercise has been acknowledged as a potent stimulus to promote, maintain, and restore healthy functioning of nearly every physiological system of the human body. With advancing understanding of the complexity of human physiology, continually evolving methodological possibilities, and an increasingly dire public health situation, the study of exercise as a preventative or therapeutic treatment has never been more interdisciplinary, or more impactful. During the early stages of the NIH Common Fund Molecular Transducers of Physical Activity Consortium (MoTrPAC) Initiative, the field is well-positioned to build substantially upon the existing understanding of the mechanisms underlying benefits associated with exercise. Thus, we present a comprehensive body of the knowledge detailing the current literature basis surrounding the molecular adaptations to exercise in humans to provide a view of the state of the field at this critical juncture, as well as a resource for scientists bringing external expertise to the field of exercise physiology. In reviewing current literature related to molecular and cellular processes underlying exercise-induced benefits and adaptations, we also draw attention to existing knowledge gaps warranting continued research effort. © 2021 American Physiological Society. Compr Physiol 12:3193-3279, 2022.
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Affiliation(s)
- Kaleen M. Lavin
- Center for Exercise Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, USA
- Department of Cell, Developmental, and Integrative Biology, The University of Alabama at Birmingham, Birmingham, Alabama, USA
- Center for Human Health, Resilience, and Performance, Institute for Human and Machine Cognition, Pensacola, Florida, USA
| | - Paul M. Coen
- Translational Research Institute for Metabolism and Diabetes, Advent Health, Orlando, Florida, USA
- Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida, USA
| | - Liliana C. Baptista
- Center for Exercise Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, USA
- Department of Medicine, Division of Gerontology, Geriatrics and Palliative Care, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Margaret B. Bell
- Center for Exercise Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, USA
- Department of Cell, Developmental, and Integrative Biology, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Devin Drummer
- Center for Exercise Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, USA
- Department of Cell, Developmental, and Integrative Biology, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Sara A. Harper
- Center for Exercise Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, USA
- Department of Medicine, Division of Gerontology, Geriatrics and Palliative Care, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Manoel E. Lixandrão
- Center for Exercise Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, USA
- Department of Cell, Developmental, and Integrative Biology, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Jeremy S. McAdam
- Center for Exercise Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, USA
- Department of Cell, Developmental, and Integrative Biology, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Samia M. O’Bryan
- Center for Exercise Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, USA
- Department of Cell, Developmental, and Integrative Biology, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Sofhia Ramos
- Translational Research Institute for Metabolism and Diabetes, Advent Health, Orlando, Florida, USA
- Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida, USA
| | - Lisa M. Roberts
- Center for Exercise Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, USA
- Department of Medicine, Division of Gerontology, Geriatrics and Palliative Care, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Rick B. Vega
- Translational Research Institute for Metabolism and Diabetes, Advent Health, Orlando, Florida, USA
- Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida, USA
| | - Bret H. Goodpaster
- Translational Research Institute for Metabolism and Diabetes, Advent Health, Orlando, Florida, USA
- Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida, USA
| | - Marcas M. Bamman
- Center for Exercise Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, USA
- Department of Cell, Developmental, and Integrative Biology, The University of Alabama at Birmingham, Birmingham, Alabama, USA
- Center for Human Health, Resilience, and Performance, Institute for Human and Machine Cognition, Pensacola, Florida, USA
| | - Thomas W. Buford
- Center for Exercise Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, USA
- Department of Medicine, Division of Gerontology, Geriatrics and Palliative Care, The University of Alabama at Birmingham, Birmingham, Alabama, USA
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13
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Thermal stress affects proliferation and differentiation of turkey satellite cells through the mTOR/S6K pathway in a growth-dependent manner. PLoS One 2022; 17:e0262576. [PMID: 35025965 PMCID: PMC8758067 DOI: 10.1371/journal.pone.0262576] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 12/29/2021] [Indexed: 12/12/2022] Open
Abstract
Satellite cells (SCs) are stem cells responsible for post-hatch muscle growth through hypertrophy and in birds are sensitive to thermal stress during the first week after hatch. The mechanistic target of rapamycin (mTOR) signaling pathway, which is highly responsive to thermal stress in differentiating turkey pectoralis major (p. major) muscle SCs, regulates protein synthesis and the activities of SCs through a downstream effector, S6 kinase (S6K). The objectives of this study were: 1) to determine the effect of heat (43°C) and cold (33°C) stress on activity of the mTOR/S6K pathway in SCs isolated from the p. major muscle of one-week-old faster-growing modern commercial (NC) turkeys compared to those from slower-growing Randombred Control Line 2 (RBC2) turkeys, and 2) to assess the effect of mTOR knockdown on the proliferation, differentiation, and expression of myogenic regulatory factors of the SCs. Heat stress increased phosphorylation of both mTOR and S6K in both turkey lines, with greater increases observed in the RBC2 line. With cold stress, greater reductions in mTOR and S6K phosphorylation were observed in the NC line. Early knockdown of mTOR decreased proliferation, differentiation, and expression of myoblast determination protein 1 and myogenin in both lines independent of temperature, with the RBC2 line showing greater reductions in proliferation and differentiation than the NC line at 38° and 43°C. Proliferating SCs are more dependent on mTOR/S6K-mediated regulation than differentiating SCs. Thus, thermal stress can affect breast muscle hypertrophic potential by changing satellite cell proliferation and differentiation, in part, through the mTOR/S6K pathway in a growth-dependent manner. These changes may result in irreversible effects on the development and growth of the turkey p. major muscle.
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14
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Viggars MR, Wen Y, Peterson CA, Jarvis JC. Automated cross-sectional analysis of trained, severely atrophied and recovering rat skeletal muscles using MyoVision 2.0. J Appl Physiol (1985) 2022; 132:593-610. [PMID: 35050795 DOI: 10.1152/japplphysiol.00491.2021] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The number of myonuclei within a muscle fiber is an important factor in muscle growth, but its regulation during muscle adaptation is not well understood. We aimed to elucidate the timecourse of myonuclear dynamics during endurance training, loaded and concentric resistance training, and nerve silencing-induced disuse atrophy with subsequent recovery. We modified tibialis anterior muscle activity in free-living rats with electrical stimulation from implantable pulse generators, or with implantable osmotic pumps delivering tetrodotoxin (TTX) to silence the motor nerve without transection. We used the updated, automated software MyoVision to measure fiber type-specific responses in whole tibialis anterior cross-sections (~8000 fibers each). Seven days of continuous low frequency stimulation (CLFS) reduced muscle mass (-12%), increased slower myosin isoforms and reduced IIX/IIB fibers (-32%) and substantially increased myonuclei especially in IIX/IIB fibers (55.5%). High load resistance training (Spillover), produced greater hypertrophy (~16%) in muscle mass and fiber cross-sectional area (CSA) than low load resistance training (concentric, ~6%) and was associated with myonuclear addition in all fiber types (35-46%). TTX-induced nerve silencing resulted in progressive loss in muscle mass, fiber CSA, and myonuclei per fiber cross-section (-50.7%, -53.7%, -40.7%, respectively at 14 days). Myonuclear loss occurred in a fiber type-independent manner, but subsequent recovery during voluntary habitual activity suggested that type IIX/IIB fibers contained more new myonuclei during recovery from severe atrophy. This study demonstrates the power and accuracy provided by the updated MyoVision software and introduces new models for studying myonuclear dynamics in training, detraining, retraining, repeated disuse, and recovery.
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Affiliation(s)
- Mark Robert Viggars
- Research Institute for Sport & Exercise Sciences, grid.4425.7Liverpool John Moores University, Liverpool, United Kingdom.,Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida, United States.,Myology Institute, University of Florida, Gainesville, Florida, United States
| | - Yuan Wen
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky, United States.,Center for Muscle Biology, University of Kentucky, Lexington, Kentucky, United States.,MyoAnalytics, LLC, Lexington, Kentucky, United States
| | - Charlotte A Peterson
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky, United States.,Center for Muscle Biology, University of Kentucky, Lexington, Kentucky, United States
| | - Jonathan C Jarvis
- Research Institute for Sport & Exercise Sciences, grid.4425.7Liverpool John Moores University, Liverpool, United Kingdom
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15
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Mesquita PHC, Vann CG, Phillips SM, McKendry J, Young KC, Kavazis AN, Roberts MD. Skeletal Muscle Ribosome and Mitochondrial Biogenesis in Response to Different Exercise Training Modalities. Front Physiol 2021; 12:725866. [PMID: 34646153 PMCID: PMC8504538 DOI: 10.3389/fphys.2021.725866] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 08/13/2021] [Indexed: 11/20/2022] Open
Abstract
Skeletal muscle adaptations to resistance and endurance training include increased ribosome and mitochondrial biogenesis, respectively. Such adaptations are believed to contribute to the notable increases in hypertrophy and aerobic capacity observed with each exercise mode. Data from multiple studies suggest the existence of a competition between ribosome and mitochondrial biogenesis, in which the first adaptation is prioritized with resistance training while the latter is prioritized with endurance training. In addition, reports have shown an interference effect when both exercise modes are performed concurrently. This prioritization/interference may be due to the interplay between the 5’ AMP-activated protein kinase (AMPK) and mechanistic target of rapamycin complex 1 (mTORC1) signaling cascades and/or the high skeletal muscle energy requirements for the synthesis and maintenance of cellular organelles. Negative associations between ribosomal DNA and mitochondrial DNA copy number in human blood cells also provide evidence of potential competition in skeletal muscle. However, several lines of evidence suggest that ribosome and mitochondrial biogenesis can occur simultaneously in response to different types of exercise and that the AMPK-mTORC1 interaction is more complex than initially thought. The purpose of this review is to provide in-depth discussions of these topics. We discuss whether a curious competition between mitochondrial and ribosome biogenesis exists and show the available evidence both in favor and against it. Finally, we provide future research avenues in this area of exercise physiology.
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Affiliation(s)
| | | | - Stuart M Phillips
- Department of Kinesiology, McMaster University, Hamilton, ON, Canada
| | - James McKendry
- Department of Kinesiology, McMaster University, Hamilton, ON, Canada
| | - Kaelin C Young
- School of Kinesiology, Auburn University, Auburn, AL, United States.,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine, Auburn, AL, United States
| | | | - Michael D Roberts
- School of Kinesiology, Auburn University, Auburn, AL, United States.,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine, Auburn, AL, United States
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16
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Vann CG, Morton RW, Mobley CB, Vechetti IJ, Ferguson BK, Haun CT, Osburn SC, Sexton CL, Fox CD, Romero MA, Roberson PA, Oikawa SY, McGlory C, Young KC, McCarthy JJ, Phillips SM, Roberts MD. An intron variant of the GLI family zinc finger 3 (GLI3) gene differentiates resistance training-induced muscle fiber hypertrophy in younger men. FASEB J 2021; 35:e21587. [PMID: 33891350 PMCID: PMC8234740 DOI: 10.1096/fj.202100113rr] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 03/17/2021] [Accepted: 03/25/2021] [Indexed: 12/25/2022]
Abstract
We examined the association between genotype and resistance training-induced changes (12 wk) in dual x-ray energy absorptiometry (DXA)-derived lean soft tissue mass (LSTM) as well as muscle fiber cross-sectional area (fCSA; vastus lateralis; n = 109; age = 22 ± 2 y, BMI = 24.7 ± 3.1 kg/m2 ). Over 315 000 genetic polymorphisms were interrogated from muscle using DNA microarrays. First, a targeted investigation was performed where single nucleotide polymorphisms (SNP) identified from a systematic literature review were related to changes in LSTM and fCSA. Next, genome-wide association (GWA) studies were performed to reveal associations between novel SNP targets with pre- to post-training change scores in mean fCSA and LSTM. Our targeted investigation revealed no genotype-by-time interactions for 12 common polymorphisms regarding the change in mean fCSA or change in LSTM. Our first GWA study indicated no SNP were associated with the change in LSTM. However, the second GWA study indicated two SNP exceeded the significance level with the change in mean fCSA (P = 6.9 × 10-7 for rs4675569, 1.7 × 10-6 for rs10263647). While the former target is not annotated (chr2:205936846 (GRCh38.p12)), the latter target (chr7:41971865 (GRCh38.p12)) is an intron variant of the GLI Family Zinc Finger 3 (GLI3) gene. Follow-up analyses indicated fCSA increases were greater in the T/C and C/C GLI3 genotypes than the T/T GLI3 genotype (P < .05). Data from the Auburn cohort also revealed participants with the T/C and C/C genotypes exhibited increases in satellite cell number with training (P < .05), whereas T/T participants did not. Additionally, those with the T/C and C/C genotypes achieved myonuclear addition in response to training (P < .05), whereas the T/T participants did not. In summary, this is the first GWA study to examine how polymorphisms associate with the change in hypertrophy measures following resistance training. Future studies are needed to determine if the GLI3 variant differentiates hypertrophic responses to resistance training given the potential link between this gene and satellite cell physiology.
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Affiliation(s)
- Christopher G Vann
- School of Kinesiology, Auburn University, Auburn, AL, USA.,Duke Molecular Physiology Institute, Duke University School of Medicine, Duke University, Durham, NC, USA
| | - Robert W Morton
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Christopher B Mobley
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, USA.,The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - Ivan J Vechetti
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA
| | | | | | | | - Casey L Sexton
- School of Kinesiology, Auburn University, Auburn, AL, USA
| | - Carlton D Fox
- School of Kinesiology, Auburn University, Auburn, AL, USA
| | | | | | - Sara Y Oikawa
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Chris McGlory
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Kaelin C Young
- School of Kinesiology, Auburn University, Auburn, AL, USA.,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine, Auburn, AL, USA
| | - John J McCarthy
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, USA.,The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - Stuart M Phillips
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Michael D Roberts
- School of Kinesiology, Auburn University, Auburn, AL, USA.,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine, Auburn, AL, USA
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17
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Vechetti IJ, Peck BD, Wen Y, Walton RG, Valentino TR, Alimov AP, Dungan CM, Van Pelt DW, von Walden F, Alkner B, Peterson CA, McCarthy JJ. Mechanical overload-induced muscle-derived extracellular vesicles promote adipose tissue lipolysis. FASEB J 2021; 35:e21644. [PMID: 34033143 DOI: 10.1096/fj.202100242r] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 04/02/2021] [Accepted: 04/19/2021] [Indexed: 02/06/2023]
Abstract
How regular physical activity is able to improve health remains poorly understood. The release of factors from skeletal muscle following exercise has been proposed as a possible mechanism mediating such systemic benefits. We describe a mechanism wherein skeletal muscle, in response to a hypertrophic stimulus induced by mechanical overload (MOV), released extracellular vesicles (EVs) containing muscle-specific miR-1 that were preferentially taken up by epidydimal white adipose tissue (eWAT). In eWAT, miR-1 promoted adrenergic signaling and lipolysis by targeting Tfap2α, a known repressor of Adrβ3 expression. Inhibiting EV release prevented the MOV-induced increase in eWAT miR-1 abundance and expression of lipolytic genes. Resistance exercise decreased skeletal muscle miR-1 expression with a concomitant increase in plasma EV miR-1 abundance, suggesting a similar mechanism may be operative in humans. Altogether, these findings demonstrate that skeletal muscle promotes metabolic adaptations in adipose tissue in response to MOV via EV-mediated delivery of miR-1.
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Affiliation(s)
- Ivan J Vechetti
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA.,Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - Bailey D Peck
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA.,Department of Physical Therapy, University of Kentucky, Lexington, KY, USA
| | - Yuan Wen
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA.,Department of Physical Therapy, University of Kentucky, Lexington, KY, USA
| | - R Grace Walton
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA.,Department of Physical Therapy, University of Kentucky, Lexington, KY, USA
| | - Taylor R Valentino
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA.,Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - Alexander P Alimov
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA.,Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - Cory M Dungan
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA.,Department of Physical Therapy, University of Kentucky, Lexington, KY, USA
| | - Douglas W Van Pelt
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA.,Department of Physical Therapy, University of Kentucky, Lexington, KY, USA
| | - Ferdinand von Walden
- Division of Neuropediatrics, Department of Women's and Children's Health, Karolinska Institutet, Solna, Sweden
| | - Björn Alkner
- Division of Neuropediatrics, Department of Women's and Children's Health, Karolinska Institutet, Solna, Sweden.,Department of Orthopaedics Eksjö, Regional Hospital Eksjö, Region Jönköping County, Sweden.,Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Charlotte A Peterson
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA.,Department of Physical Therapy, University of Kentucky, Lexington, KY, USA
| | - John J McCarthy
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA.,Department of Physiology, University of Kentucky, Lexington, KY, USA
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18
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Kotani T, Takegaki J, Tamura Y, Kouzaki K, Nakazato K, Ishii N. Repeated bouts of resistance exercise in rats alter mechanistic target of rapamycin complex 1 activity and ribosomal capacity but not muscle protein synthesis. Exp Physiol 2021; 106:1950-1960. [PMID: 34197668 DOI: 10.1113/ep089699] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 06/30/2021] [Indexed: 01/03/2023]
Abstract
NEW FINDINGS What is the central question of this study? Is muscle protein synthesis (MPS) additionally activated following exercise when ribosomal capacity is increased after repeated bouts of resistance exercise (RE)? What is the main finding and its importance? Skeletal muscles with increased ribosome content through repeated RE bouts showed sufficient activation of MPS with lower mechanistic target of rapamycin complex 1 signalling. Thus, repeated bouts of RE possibly change the translational capacity and efficiency to optimize translation activation following RE. ABSTRACT Resistance exercise (RE) activates ribosome biogenesis and increases ribosome content in skeletal muscles. However, it is unclear whether the increase in ribosome content subsequently causes an increase in RE-induced activation of muscle protein synthesis (MPS). Thus, this study aimed to investigate the relationship between ribosome content and MPS after exercise using a rat RE model. Male Sprague-Dawley rats were categorized into three groups (n = 6 for each group): sedentary (SED) and RE trained with one bout (1B) or three bouts (3B). The RE stimulus was applied to the right gastrocnemius muscle by transcutaneous electrical stimulation under isoflurane anaesthesia. The 3B group underwent stimulation every other day. Our results revealed that 6 h after the last bout of RE, muscles in the 3B group showed an increase in total RNA and 18S+28S rRNA content per muscle weight compared with the SED and 1B groups. In both the 1B and 3B groups, MPS, estimated by puromycin incorporation in proteins, was higher than that in the SED group 6 h after exercise; however, no significant difference was observed between the 1B and 3B groups. In the 1B and 3B groups, phosphorylated p70S6K at Thr-389 increased, indicating mechanistic target of rapamycin complex 1 (mTORC1) activity. p70S6K phosphorylation level was lower in the 3B group than in the 1B group. Finally, protein synthesis per ribosome (indicator of translation efficiency) was lower in the 3B group than in the 1B group. Thus, three bouts of RE changed the ribosome content and mTORC1 activation, but not the degree of RE-induced global MPS activation.
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Affiliation(s)
- Takaya Kotani
- Research Institute for Sport Science, Nippon Sport Science University, Tokyo, Japan
| | - Junya Takegaki
- Ritsumeikan Global Innovation Research Organization, Ritsumeikan University, Shiga, Japan
| | - Yuki Tamura
- Research Institute for Sport Science, Nippon Sport Science University, Tokyo, Japan.,Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan.,Faculty of Sport Science, Nippon Sport Science University, Tokyo, Japan
| | - Karina Kouzaki
- Research Institute for Sport Science, Nippon Sport Science University, Tokyo, Japan.,Graduate School of Medical and Health Science, Nippon Sport Science University, Tokyo, Japan.,Faculty of Medical Science, Nippon Sport Science University, Tokyo, Japan
| | - Koichi Nakazato
- Research Institute for Sport Science, Nippon Sport Science University, Tokyo, Japan.,Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan.,Graduate School of Medical and Health Science, Nippon Sport Science University, Tokyo, Japan.,Faculty of Medical Science, Nippon Sport Science University, Tokyo, Japan
| | - Naokata Ishii
- Graduate School or Arts and Sciences, The University of Tokyo, Tokyo, Japan
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19
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Kotani T, Takegaki J, Tamura Y, Kouzaki K, Nakazato K, Ishii N. The effect of repeated bouts of electrical stimulation-induced muscle contractions on proteolytic signaling in rat skeletal muscle. Physiol Rep 2021; 9:e14842. [PMID: 33991444 PMCID: PMC8123562 DOI: 10.14814/phy2.14842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 03/16/2021] [Indexed: 11/24/2022] Open
Abstract
Mechanistic target of rapamycin complex 1 (mTORC1) plays a central role in muscle protein synthesis and repeated bouts of resistance exercise (RE) blunt mTORC1 activation. However, the changes in the proteolytic signaling when recurrent RE bouts attenuate mTORC1 activation are unclear. Using a RE model of electrically stimulated rat skeletal muscle, this study aimed to clarify the effect of repeated RE bouts on acute proteolytic signaling, particularly the calpain, autophagy‐lysosome, and ubiquitin‐proteasome pathway. p70S6K and rpS6 phosphorylation, indicators of mTORC1 activity, were attenuated by repeated RE bouts. Calpain 3 protein was decreased at 6 h post‐RE in all exercised groups regardless of the bout number. Microtubule‐associated protein 1 light chain 3 beta‐II, an indicator of autophagosome formation, was increased at 3 h and repeated RE bouts increased at 6 h, post‐RE. Ubiquitinated proteins were increased following RE, but these increases were independent of the number of RE bouts. These results suggest that the magnitude of autophagosome formation was increased following RE when mTORC1 activity was attenuated with repeated bouts of RE.
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Affiliation(s)
- Takaya Kotani
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan.,Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan
| | - Junya Takegaki
- Ritsumeikan Global Innovation Research Organization, Ritsumeikan University, Shiga, Japan
| | - Yuki Tamura
- Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan
| | - Karina Kouzaki
- Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan
| | - Koichi Nakazato
- Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan
| | - Naokata Ishii
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
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20
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Structure-based modification of pyrazolone derivatives to inhibit mTORC1 by targeting the leucyl-tRNA synthetase-RagD interaction. Bioorg Chem 2021; 112:104907. [PMID: 33979735 DOI: 10.1016/j.bioorg.2021.104907] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 03/21/2021] [Accepted: 04/07/2021] [Indexed: 12/13/2022]
Abstract
The enzyme leucyl-tRNA synthetase (LRS) and the amino acid leucine regulate the mechanistic target of rapamycin (mTOR) signaling pathway. Leucine-dependent mTORC1 activation depends on GTPase activating protein events mediated by LRS. In a prior study, compound BC-LI-0186 was discovered and shown to interfere with the mTORC1 signaling pathway by inhibiting the LRS-RagD interaction. However, BC-LI-0186 exhibited poor solubility and was metabolized by human liver microsomes. In this study, in silico physicochemical properties and metabolite analysis of BC-LI-0186 are used to investigate the addition of functional groups to improve solubility and microsomal stability. In vitro experiments demonstrated that 7b and 8a had improved chemical properties while still maintaining inhibitory activity against mTORC1. The results suggest a new strategy for the discovery of novel drug candidates and the treatment of diverse mTORC1-related diseases.
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21
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Saud A, Luiz RS, Leite APO, Muller CR, Visona I, Reinecke N, Silva WH, Gloria MA, Razvickas CV, Casarini DE, Schor N. Resistance exercise training ameliorates chronic kidney disease outcomes in a 5/6 nephrectomy model. Life Sci 2021; 275:119362. [PMID: 33741414 DOI: 10.1016/j.lfs.2021.119362] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 03/03/2021] [Accepted: 03/08/2021] [Indexed: 11/15/2022]
Abstract
Chronic kidney disease (CKD) is defined by decreased glomerular filtration rate (GFR) or increased albumin excretion leading to renal injury. However, exercise training is an important non-pharmacological intervention that ameliorates and protects against Diabetes Mellitus, cardiovascular disease, and CKD. AIM Our aim was to evaluate the capability of resistance exercise training (RET) to improve CKD outcomes and the contribution of the renal and muscular Akt/mTOR signaling pathway for RET beneficial effects on a CKD model. MAIN METHODS Male Wistar rats were subjected to RET, followed for 10 weeks, and randomly divided into 5 groups: Sham: Sham-operated; sedentary and nephrectomy (5/6Nx) (SNS); exercising post-5/6Nx (SNE); exercising pre-5/6Nx (ENS); exercising pre- and post-5/6Nx (ENE). The systolic blood pressure (BP) was measured. Creatinine, proteinuria, and blood urea nitrogen (BUN) were evaluated. After euthanasia Renal and muscular Akt/mTOR signaling pathways were analyzed. KEY FINDING Our study showed that the SNS presented renal injury, hypertension, weight and muscular mass loss and a higher mortality rate. SNS group also decreased renal IL-10 and increased TNF-alfa and TGF-Beta. Renal AKT, mTOR, and rpS6 pathway were increased, PTEN was decreased on SNS. And muscular Akt and mTOR were decreased on SNS. SIGNIFICANCE The RET before and after the 5/6Nx ameliorates all these parameters mentioned above, suggesting that RET is a good non-pharmacological approach to diminish complications frequently found in CKD. We also suggest that the AKT-m-TOR pathway can play an important role in these beneficial outcomes of RET on the CKD animal model.
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Affiliation(s)
- A Saud
- Departamento de Medicina, Disciplina de Nefrologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, SP, Brazil
| | - R S Luiz
- Departamento de Medicina, Disciplina de Nefrologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, SP, Brazil
| | - A P O Leite
- Departamento de Medicina, Disciplina de Nefrologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, SP, Brazil; Tulane University, Department of Physiology & Medicine, New Orleans, LA, United States
| | - C R Muller
- Department of Bioengineering, University of California San Diego, La Jolla, CA, United States
| | - I Visona
- Departamento de Patologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, SP, Brazil
| | - N Reinecke
- Departamento de Medicina, Disciplina de Nefrologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, SP, Brazil
| | - W H Silva
- Departamento de Medicina, Disciplina de Nefrologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, SP, Brazil
| | - M A Gloria
- Departamento de Medicina, Disciplina de Nefrologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, SP, Brazil
| | - C V Razvickas
- Departamento de Medicina, Disciplina de Nefrologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, SP, Brazil
| | - D E Casarini
- Departamento de Medicina, Disciplina de Nefrologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, SP, Brazil.
| | - N Schor
- Departamento de Medicina, Disciplina de Nefrologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, SP, Brazil
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22
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Von Walden F, Rea M, Mobley CB, Fondufe-Mittendorf Y, McCarthy JJ, Peterson CA, Murach KA. The myonuclear DNA methylome in response to an acute hypertrophic stimulus. Epigenetics 2020; 15:1151-1162. [PMID: 32281477 PMCID: PMC7595631 DOI: 10.1080/15592294.2020.1755581] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
In addition to multi-nucleated muscle fibres, numerous resident and infiltrating mononuclear cells populate the muscle compartment. As most epigenetic assays in skeletal muscle are conducted on whole tissue homogenates, essentially nothing is known about regulatory processes exclusively within muscle fibres in vivo. Utilizing a novel genetically modified mouse model developed by our laboratory, we (1) outline a simple and rapid workflow for isolating pure myonuclei from small tissue samples via fluorescent activated cell sorting and extracting high-quality large-fragment DNA for downstream analyses, and (2) provide information on myonuclear and interstitial cell nuclear CpG DNA methylation via reduced representation bisulphite sequencing (RRBS) using mice that were subjected to an acute mechanical overload of the plantaris muscle. In 3-month-old mice, myonuclei are ~50% of total nuclei in sham and ~30% in 3-d overloaded muscle, the difference being attributable to mononuclear cell infiltration and proliferation with overload. In purified myonuclei, pathway analysis of hypomethylated promoter regions following overload was distinct from interstitial nuclei and revealed marked regulation of factors that converge on the master regulator of muscle growth mTOR, and on autophagy. Specifically, acute hypomethylation of Rheb, Rictor, Hdac1, and Hdac2, in addition to a major driver of ribosome biogenesis Myc, reveals the epigenetic regulation of hypertrophic signalling within muscle fibres that may underpin the long-term growth response to loading. This study provides foundational information on global myonuclear epigenetics in vivo using RRBS, and demonstrates the importance of isolating specific nuclear populations to study the epigenetic regulation of skeletal muscle fibre adaptation.
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Affiliation(s)
- Ferdinand Von Walden
- K6 Department of Women’s and Children’s Health, Karolinska Institute, Stockholm, Sweden
- Department of Physiology, University of Kentucky, Lexington, KY, USA
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - Matthew Rea
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA
| | - C. Brooks Mobley
- Department of Physiology, University of Kentucky, Lexington, KY, USA
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | | | - John J. McCarthy
- Department of Physiology, University of Kentucky, Lexington, KY, USA
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - Charlotte A. Peterson
- Department of Physiology, University of Kentucky, Lexington, KY, USA
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Physical Therapy, University of Kentucky, Lexington, KY, USA
| | - Kevin A. Murach
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Physical Therapy, University of Kentucky, Lexington, KY, USA
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23
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Balnis J, Lee CG, Elias JA, Jaitovich A. Hypercapnia-Driven Skeletal Muscle Dysfunction in an Animal Model of Pulmonary Emphysema Suggests a Complex Phenotype. Front Physiol 2020; 11:600290. [PMID: 33192616 PMCID: PMC7658396 DOI: 10.3389/fphys.2020.600290] [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: 08/29/2020] [Accepted: 10/08/2020] [Indexed: 12/11/2022] Open
Abstract
Patients with chronic pulmonary conditions such as chronic obstructive pulmonary disease (COPD) often develop skeletal muscle dysfunction, which is strongly and independently associated with poor outcomes including higher mortality. Some of these patients also develop chronic CO2 retention, or hypercapnia, which is also associated with worse prognosis. While muscle dysfunction in these settings involve reduction of muscle mass and disrupted fibers’ metabolism leading to suboptimal muscle work, mechanistic research in the field has been limited by the lack of adequate animal models. Over the last years, we have established a rodent model of COPD-induced skeletal muscle dysfunction that allowed a disaggregated interrogation of the cellular and physiological effects driven by COPD from the ones unique to hypercapnia. We found that while COPD and hypercapnia synergistically contribute to muscle atrophy, they are antagonistic processes regarding fibers respiratory capacity. We propose that AMP-activated protein kinase (AMPK) is a crucial regulator of CO2 signaling in hypercapnic muscles, which leads to both net protein catabolism and improved mitochondrial respiration to support a transition into a substrate-rich, fuel-efficient metabolic mode that allows muscle cells cope with the CO2 toxicity.
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Affiliation(s)
- Joseph Balnis
- Division of Pulmonary and Critical Care Medicine, Albany Medical College, Albany, NY, United States.,Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, United States
| | - Chun Geun Lee
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, United States
| | - Jack A Elias
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, United States
| | - Ariel Jaitovich
- Division of Pulmonary and Critical Care Medicine, Albany Medical College, Albany, NY, United States.,Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, United States
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24
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Emphasizing Task-Specific Hypertrophy to Enhance Sequential Strength and Power Performance. J Funct Morphol Kinesiol 2020; 5:jfmk5040076. [PMID: 33467291 PMCID: PMC7739346 DOI: 10.3390/jfmk5040076] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 10/04/2020] [Accepted: 10/21/2020] [Indexed: 12/15/2022] Open
Abstract
While strength is indeed a skill, most discussions have primarily considered structural adaptations rather than ultrastructural augmentation to improve performance. Altering the structural component of the muscle is often the aim of hypertrophic training, yet not all hypertrophy is equal; such alterations are dependent upon how the muscle adapts to the training stimuli and overall training stress. When comparing bodybuilders to strength and power athletes such as powerlifters, weightlifters, and throwers, while muscle size may be similar, the ability to produce force and power is often inequivalent. Thus, performance differences go beyond structural changes and may be due to the muscle's ultrastructural constituents and training induced adaptations. Relative to potentiating strength and power performances, eliciting specific ultrastructural changes should be a variable of interest during hypertrophic training phases. By focusing on task-specific hypertrophy, it may be possible to achieve an optimal amount of hypertrophy while deemphasizing metabolic and aerobic components that are often associated with high-volume training. Therefore, the purpose of this article is to briefly address different types of hypertrophy and provide directions for practitioners who are aiming to achieve optimal rather than maximal hypertrophy, as it relates to altering ultrastructural muscular components, to potentiate strength and power performance.
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25
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Water Extract of Lotus Leaf Alleviates Dexamethasone-Induced Muscle Atrophy via Regulating Protein Metabolism-Related Pathways in Mice. Molecules 2020; 25:molecules25204592. [PMID: 33050143 PMCID: PMC7587191 DOI: 10.3390/molecules25204592] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 09/30/2020] [Accepted: 10/02/2020] [Indexed: 12/17/2022] Open
Abstract
Muscle atrophy is an abnormal condition characterized by loss of skeletal muscle mass and function and is primarily caused by injury, malnutrition, various diseases, and aging. Leaf of lotus (Nelumbo nucifera Gaertn), which has been used for medicinal purposes, contains various active ingredients, including polyphenols, and is reported to exert an antioxidant effect. In this study, we investigated the effect of water extract of lotus leaf (LL) on muscle atrophy and the underlying molecular mechanisms of action. Amounts of 100, 200, or 300 mg/kg/day LL were administered to dexamethasone (DEX)-induced muscle atrophy mice for 4 weeks. Micro-computed tomography (CT) analysis revealed that the intake of LL significantly increased calf muscle volume, surface area, and density in DEX-induced muscle atrophy mice. Administration of LL recovered moving distance, grip strength, ATP production, and body weight, which were decreased by DEX. In addition, muscle damage caused by DEX was also improved by LL. LL reduced the protein catabolic pathway by suppressing gene expression of muscle atrophy F-Box (MAFbx; atrogin-1), muscle RING finger 1 (MuRF1), and forkhead box O (FoxO)3a, as well as phosphorylation of AMP-activated kinase (AMPK). The AKT-mammalian target of the rapamycin (mTOR) signal pathway, which is important for muscle protein synthesis, was increased in LL-administered groups. The HPLC analysis and pharmacological test revealed that quercetin 3-O-beta-glucuronide (Q3G) is a major active component in LL. Thus, Q3G decreased the gene expression of atrogin-1 and MuRF1 and phosphorylation of AMPK. This compound also increased phosphorylation levels of mTOR and its upstream enzyme AKT in DEX-treated C2C12 cells. We identified that LL improves muscle wasting through regulation of muscle protein metabolism in DEX-induced muscle atrophy mice. Q3G is predicted to be one of the major active phenolic components in LL. Therefore, we propose LL as a supplement or therapeutic agent to prevent or treat muscle wasting, such as sarcopenia.
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26
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Koutnik AP, Poff AM, Ward NP, DeBlasi JM, Soliven MA, Romero MA, Roberson PA, Fox CD, Roberts MD, D'Agostino DP. Ketone Bodies Attenuate Wasting in Models of Atrophy. J Cachexia Sarcopenia Muscle 2020; 11:973-996. [PMID: 32239651 PMCID: PMC7432582 DOI: 10.1002/jcsm.12554] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 01/18/2020] [Accepted: 01/30/2020] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Cancer Anorexia Cachexia Syndrome (CACS) is a distinct atrophy disease negatively influencing multiple aspects of clinical care and patient quality of life. Although it directly causes 20% of all cancer-related deaths, there are currently no model systems that encompass the entire multifaceted syndrome, nor are there any effective therapeutic treatments. METHODS A novel model of systemic metastasis was evaluated for the comprehensive CACS (metastasis, skeletal muscle and adipose tissue wasting, inflammation, anorexia, anemia, elevated protein breakdown, hypoalbuminemia, and metabolic derangement) in both males and females. Ex vivo skeletal muscle analysis was utilized to determine ubiquitin proteasome degradation pathway activation. A novel ketone diester (R/S 1,3-Butanediol Acetoacetate Diester) was assessed in multifaceted catabolic environments to determine anti-atrophy efficacy. RESULTS Here, we show that the VM-M3 mouse model of systemic metastasis demonstrates a novel, immunocompetent, logistically feasible, repeatable phenotype with progressive tumor growth, spontaneous metastatic spread, and the full multifaceted CACS with sex dimorphisms across tissue wasting. We also demonstrate that the ubiquitin proteasome degradation pathway was significantly upregulated in association with reduced insulin-like growth factor-1/insulin and increased FOXO3a activation, but not tumor necrosis factor-α-induced nuclear factor-kappa B activation, driving skeletal muscle atrophy. Additionally, we show that R/S 1,3-Butanediol Acetoacetate Diester administration shifted systemic metabolism, attenuated tumor burden indices, reduced atrophy/catabolism and mitigated comorbid symptoms in both CACS and cancer-independent atrophy environments. CONCLUSIONS Our findings suggest the ketone diester attenuates multifactorial CACS skeletal muscle atrophy and inflammation-induced catabolism, demonstrating anti-catabolic effects of ketone bodies in multifactorial atrophy.
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Affiliation(s)
- Andrew P. Koutnik
- Department of Molecular Pharmacology and PhysiologyMorsani College of Medicine, University of South FloridaTampaFLUSA
| | - Angela M. Poff
- Department of Molecular Pharmacology and PhysiologyMorsani College of Medicine, University of South FloridaTampaFLUSA
| | - Nathan P. Ward
- Department of Cancer PhysiologyMoffitt Cancer Center, H. Lee Moffitt Cancer Center and Research InstituteTampaFLUSA
| | - Janine M. DeBlasi
- Department of Molecular Pharmacology and PhysiologyMorsani College of Medicine, University of South FloridaTampaFLUSA
| | - Maricel A. Soliven
- Department of Molecular Pharmacology and PhysiologyMorsani College of Medicine, University of South FloridaTampaFLUSA
| | | | | | - Carl D. Fox
- School of KinesiologyAuburn UniversityAuburnALUSA
| | | | - Dominic P. D'Agostino
- Department of Molecular Pharmacology and PhysiologyMorsani College of Medicine, University of South FloridaTampaFLUSA
- Institute for Human and Machine CognitionOcalaFLUSA
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27
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Lawrence MM, Van Pelt DW, Confides AL, Hunt ER, Hettinger ZR, Laurin JL, Reid JJ, Peelor FF, Butterfield TA, Dupont-Versteegden EE, Miller BF. Massage as a mechanotherapy promotes skeletal muscle protein and ribosomal turnover but does not mitigate muscle atrophy during disuse in adult rats. Acta Physiol (Oxf) 2020; 229:e13460. [PMID: 32125770 PMCID: PMC7293583 DOI: 10.1111/apha.13460] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 02/25/2020] [Accepted: 02/26/2020] [Indexed: 12/12/2022]
Abstract
AIM Interventions that decrease atrophy during disuse are desperately needed to maintain muscle mass. We recently found that massage as a mechanotherapy can improve muscle regrowth following disuse atrophy. Therefore, we aimed to determine if massage has similar anabolic effects when applied during normal weight bearing conditions (WB) or during atrophy induced by hindlimb suspension (HS) in adult rats. METHODS Adult (10 months) male Fischer344-Brown Norway rats underwent either hindlimb suspension (HS, n = 8) or normal WB (WB, n = 8) for 7 days. Massage was applied using cyclic compressive loading (CCL) in WB (WBM, n = 9) or HS rats (HSM, n = 9) and included four 30-minute bouts of CCL applied to gastrocnemius muscle every other day. RESULTS Massage had no effect on any anabolic parameter measured under WB conditions (WBM). In contrast, massage during HS (HSM) stimulated protein turnover, but did not mitigate muscle atrophy. Atrophy from HS was caused by both lowered protein synthesis and higher degradation. HS and HSM had lowered total RNA compared with WB and this was the result of significantly higher ribosome degradation in HS that was attenuated in HSM, without differences in ribosomal biogenesis. Also, massage increased protein turnover in the non-massaged contralateral limb during HS. Finally, we determined that total RNA degradation primarily dictates loss of muscle ribosomal content during disuse atrophy. CONCLUSION We conclude that massage is an effective mechanotherapy to impact protein turnover during muscle disuse in both the massaged and non-massaged contralateral muscle, but it does not attenuate the loss of muscle mass.
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Affiliation(s)
- Marcus M. Lawrence
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Douglas W. Van Pelt
- Department of Physical Therapy, University of Kentucky, Lexington, KY 40536, USA
- Center for Muscle Biology, University of Kentucky, Lexington, KY 40536, USA
| | - Amy L. Confides
- Department of Physical Therapy, University of Kentucky, Lexington, KY 40536, USA
- Center for Muscle Biology, University of Kentucky, Lexington, KY 40536, USA
| | - Emily R. Hunt
- Department of Physical Therapy, University of Kentucky, Lexington, KY 40536, USA
- Center for Muscle Biology, University of Kentucky, Lexington, KY 40536, USA
| | - Zachary R. Hettinger
- Department of Physical Therapy, University of Kentucky, Lexington, KY 40536, USA
- Center for Muscle Biology, University of Kentucky, Lexington, KY 40536, USA
| | - Jaime L. Laurin
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Justin J. Reid
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Frederick F. Peelor
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Timothy A. Butterfield
- Center for Muscle Biology, University of Kentucky, Lexington, KY 40536, USA
- Department of Athletic Training and Clinical Nutrition, University of Kentucky, Lexington, KY 40536, USA
| | - Esther E. Dupont-Versteegden
- Department of Physical Therapy, University of Kentucky, Lexington, KY 40536, USA
- Center for Muscle Biology, University of Kentucky, Lexington, KY 40536, USA
| | - Benjamin F. Miller
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
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28
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Microtubule Organization in Striated Muscle Cells. Cells 2020; 9:cells9061395. [PMID: 32503326 PMCID: PMC7349303 DOI: 10.3390/cells9061395] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 05/25/2020] [Accepted: 05/28/2020] [Indexed: 12/13/2022] Open
Abstract
Distinctly organized microtubule networks contribute to the function of differentiated cell types such as neurons, epithelial cells, skeletal myotubes, and cardiomyocytes. In striated (i.e., skeletal and cardiac) muscle cells, the nuclear envelope acts as the dominant microtubule-organizing center (MTOC) and the function of the centrosome—the canonical MTOC of mammalian cells—is attenuated, a common feature of differentiated cell types. We summarize the mechanisms known to underlie MTOC formation at the nuclear envelope, discuss the significance of the nuclear envelope MTOC for muscle function and cell cycle progression, and outline potential mechanisms of centrosome attenuation.
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29
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Roberson PA, Shimkus KL, Welles JE, Xu D, Whitsell AL, Kimball EM, Jefferson LS, Kimball SR. A time course for markers of protein synthesis and degradation with hindlimb unloading and the accompanying anabolic resistance to refeeding. J Appl Physiol (1985) 2020; 129:36-46. [PMID: 32407240 DOI: 10.1152/japplphysiol.00155.2020] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Skeletal muscle atrophy is associated with disease, aging, and disuse. Hindlimb unloading (HU) in animals provides an experimental model to study muscle atrophy. A comprehensive time course for how HU affects biomarkers of protein synthesis and degradation acutely and chronically and the associated resistance to an anabolic stimulus following disuse remain undocumented. Sixteen-week-old C57BL/6 mice underwent 0, 1, 12, 24, 72, 168, or 336 h of HU. Following 336 h of HU, mice were reloaded for 1, 24, or 72 h. Another group of mice underwent 120 h of HU, were fasted or refed, and were then compared with similar condition control animals (CTL). Protein content and phosphorylation of biomarkers of protein synthesis, degradation, and autophagy were assessed in the soleus muscle. Gastrocnemius, soleus, and plantaris muscles atrophied within 120 h of HU. Protein synthesis trended toward decrease following 24 h of HU. p70S6K phosphorylation and protein synthesis increased with reloading. Following HU, changes in MAFbx and DEPTOR expression and DEPTOR phosphorylation were consistent with development of a catabolic state. DEPTOR expression recovered following reloading. Animals that underwent 120 h of HU exhibited attenuation of refeeding-induced p70S6K phosphorylation compared with CTL counterparts. Following 120 h of HU, protein synthesis, eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) phosphorylation, and DEPTOR, MAFbx, and Sestrin1 expression indicated a catabolic state. Following 120 h of HU, autophagy markers, including p62 expression, REDD1 expression, LC3 ratio, and Unc-51-like autophagy-activating kinase 1 (ULK1) phosphorylation, indicated impaired autophagy. HU promotes a deleterious balance between protein synthesis and degradation. The time course herein provides scientists information about when the associated biomarkers become affected.NEW & NOTEWORTHY Hindlimb unloading causes significant skeletal muscle atrophy by adversely affecting the balance between protein synthesis and breakdown. This study demonstrates a more complete time course for changes in biomarkers associated with protein synthesis and breakdown and investigates the associated anabolic resistance to an anabolic stimulus following hindlimb unloading. These data in concert with information from other studies provide a basis for designing future experiments to optimally interrogate a desired cellular biomarker or pathway.
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Affiliation(s)
- Paul A Roberson
- Pennsylvania State University, Department of Cellular and Molecular Physiology, College of Medicine, Hershey, Pennsylvania
| | - Kevin L Shimkus
- Pennsylvania State University, Department of Cellular and Molecular Physiology, College of Medicine, Hershey, Pennsylvania
| | - Jaclyn E Welles
- Pennsylvania State University, Department of Cellular and Molecular Physiology, College of Medicine, Hershey, Pennsylvania
| | - Dandan Xu
- Pennsylvania State University, Department of Cellular and Molecular Physiology, College of Medicine, Hershey, Pennsylvania
| | - Abigale L Whitsell
- Pennsylvania State University, Department of Cellular and Molecular Physiology, College of Medicine, Hershey, Pennsylvania
| | - Eric M Kimball
- Pennsylvania State University, Department of Cellular and Molecular Physiology, College of Medicine, Hershey, Pennsylvania
| | - Leonard S Jefferson
- Pennsylvania State University, Department of Cellular and Molecular Physiology, College of Medicine, Hershey, Pennsylvania
| | - Scot R Kimball
- Pennsylvania State University, Department of Cellular and Molecular Physiology, College of Medicine, Hershey, Pennsylvania
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30
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Korponay TC, Balnis J, Vincent CE, Singer DV, Chopra A, Adam AP, Ginnan R, Singer HA, Jaitovich A. High CO 2 Downregulates Skeletal Muscle Protein Anabolism via AMP-activated Protein Kinase α2-mediated Depressed Ribosomal Biogenesis. Am J Respir Cell Mol Biol 2020; 62:74-86. [PMID: 31264907 DOI: 10.1165/rcmb.2019-0061oc] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
High CO2 retention, or hypercapnia, is associated with worse outcomes in patients with chronic pulmonary diseases. Skeletal muscle wasting is also an independent predictor of poor outcomes in patients with acute and chronic pulmonary diseases. Although previous evidence indicates that high CO2 accelerates skeletal muscle catabolism via AMPK (AMP-activated protein kinase)-FoxO3a-MuRF1 (E3-ubiquitin ligase muscle RING finger protein 1), little is known about the role of high CO2 in regulating skeletal muscle anabolism. In the present study, we investigated the potential role of high CO2 in attenuating skeletal muscle protein synthesis. We found that locomotor muscles from patients with chronic CO2 retention demonstrated depressed ribosomal gene expression in comparison with locomotor muscles from non-CO2-retaining individuals, and analysis of the muscle proteome of normo- and hypercapnic mice indicates reduction of important components of ribosomal structure and function. Indeed, mice chronically kept under a high-CO2 environment show evidence of skeletal muscle downregulation of ribosomal biogenesis and decreased protein synthesis as measured by the incorporation of puromycin into skeletal muscle. Hypercapnia did not regulate the mTOR pathway, and rapamycin-induced deactivation of mTOR did not cause a decrease in ribosomal gene expression. Loss-of-function studies in cultured myotubes showed that AMPKα2 regulates CO2-mediated reductions in ribosomal gene expression and protein synthesis. Although previous evidence has implicated TIF1A (transcription initiation factor-1α) and KDM2A (lysine-specific demethylase 2A) in AMPK-driven regulation of ribosomal gene expression, we found that these mediators were not required in the high CO2-induced depressed protein anabolism. Our research supports future studies targeting ribosomal biogenesis and protein synthesis to alleviate the effects of high CO2 on skeletal muscle turnover.
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Affiliation(s)
- Tanner C Korponay
- Division of Pulmonary and Critical Care Medicine.,Department of Molecular and Cellular Physiology, and
| | - Joseph Balnis
- Division of Pulmonary and Critical Care Medicine.,Department of Molecular and Cellular Physiology, and
| | | | | | - Amit Chopra
- Division of Pulmonary and Critical Care Medicine
| | - Alejandro P Adam
- Department of Molecular and Cellular Physiology, and.,Department of Ophthalmology, Albany Medical College, Albany, New York; and
| | - Roman Ginnan
- Department of Molecular and Cellular Physiology, and
| | | | - Ariel Jaitovich
- Division of Pulmonary and Critical Care Medicine.,Department of Molecular and Cellular Physiology, and
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31
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Lepley LK, Davi SM, Hunt ER, Burland JP, White MS, McCormick GY, Butterfield TA. Morphology and Anabolic Response of Skeletal Muscles Subjected to Eccentrically or Concentrically Biased Exercise. J Athl Train 2020; 55:336-342. [PMID: 32196379 DOI: 10.4085/1062-6050-174-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
CONTEXT Long-term eccentric exercise is known to promote muscle growth better than concentric exercise, but its acute effect on muscle is not well understood because of misinterpreted modeling and in situ and in vitro stretch protocols. Knowing if the initial bout of eccentric exercise promotes muscle growth and limits damage is critical to understanding the effect of this mode of exercise. OBJECTIVE To directly evaluate the immediate effects of eccentric and concentric exercises on untrained muscle when fiber strains were physiological and exercise doses were comparable. DESIGN Controlled laboratory study. SETTING Laboratory. PATIENTS OR OTHER PARTICIPANTS A total of 40 skeletally mature male Long-Evans rats (age = 16 weeks, mass = 452.1 ± 35.2 g) were randomly assigned to an eccentric exercise (downhill walking, n = 16), concentric exercise (uphill walking, n = 16), or control (no exercise, n = 8) group. INTERVENTION(S) Rats were exposed to a single 15-minute bout of eccentric or concentric exercise on a motorized treadmill and then were euthanized at 6 or 24 hours postexercise. We harvested the vastus lateralis muscle bilaterally. MAIN OUTCOME MEASURE(S) The percentage increase or decrease in protein abundance in exercised animals relative to that in unexercised control animals was evaluated as elevated phosphorylated p70S6k relative to total p70S6k. Fiber damage was quantified using immunoglobulin G permeability staining. One-way analysis of variance and post hoc Tukey tests were performed. RESULTS Rats exposed to eccentric exercise and euthanized at 24 hours had higher percentage response protein synthesis rates than rats exposed to eccentric exercise and euthanized at 6 hours (P = .02) or to concentric exercise and euthanized at 6 (P = .03) or 24 (P = .03) hours. We assessed 9446 fibers for damage and found only 1 fiber was infiltrated (in the concentric exercise group euthanized at 6 hours). Furthermore, no between-groups differences in immunoglobulin G fluorescent intensity were detected (P = .94). CONCLUSIONS Incorporating eccentric exercise is a simple, universally available therapeutic intervention for promoting muscle recovery. A single 15-minute dose of eccentric exercise to a novice muscle can better exert an anabolic effect than a comparable dose of concentric exercise, with very limited evidence of fiber damage.
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Affiliation(s)
| | - Steven M Davi
- Department of Kinesiology, University of Connecticut, Storrs
| | - Emily R Hunt
- Department of Rehabilitation Sciences, University of Kentucky, Lexington.,Center for Muscle Biology, University of Kentucky, Lexington
| | - Julie P Burland
- Spaulding National Running Center, Harvard Medical School, Boston, MA
| | | | | | - Timothy A Butterfield
- Department of Rehabilitation Sciences, University of Kentucky, Lexington.,Center for Muscle Biology, University of Kentucky, Lexington
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32
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Hammarström D, Øfsteng S, Koll L, Hanestadhaugen M, Hollan I, Apró W, Whist JE, Blomstrand E, Rønnestad BR, Ellefsen S. Benefits of higher resistance-training volume are related to ribosome biogenesis. J Physiol 2020; 598:543-565. [PMID: 31813190 DOI: 10.1113/jp278455] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 12/03/2019] [Indexed: 12/25/2022] Open
Abstract
KEY POINTS For individuals showing suboptimal adaptations to resistance training, manipulation of training volume is a potential measure to facilitate responses. This remains unexplored. Here, 34 untrained individuals performed contralateral resistance training with moderate and low volume for 12 weeks. Moderate volume led to larger increases in muscle cross-sectional area, strength and type II fibre-type transitions. These changes coincided with greater activation of signalling pathways controlling muscle growth and greater induction of ribosome synthesis. Out of 34 participants, thirteen displayed clear benefit of MOD on muscle hypertrophy and sixteen showed clear benefit of MOD on muscle strength gains. This coincided with greater total RNA accumulation in the early phase of the training period, suggesting that ribosomal biogenesis regulates the dose-response relationship between training volume and muscle hypertrophy. These results demonstrate that there is a dose-dependent relationship between training volume and outcomes. On the individual level, benefits of higher training volume were associated with increased ribosomal biogenesis. ABSTRACT Resistance-exercise volume is a determinant of training outcomes. However not all individuals respond in a dose-dependent fashion. In this study, 34 healthy individuals (males n = 16, 23.6 (4.1) years; females n = 18, 22.0 (1.3) years) performed moderate- (3 sets per exercise, MOD) and low-volume (1 set, LOW) resistance training in a contralateral fashion for 12 weeks (2-3 sessions per week). Muscle cross-sectional area (CSA) and strength were assessed at Weeks 0 and 12, along with biopsy sampling (m. vastus lateralis). Muscle biopsies were also sampled before and 1 h after the fifth session (Week 2). MOD resulted in larger increases in muscle CSA (5.2 (3.8)% versus 3.7 (3.7)%, P < 0.001) and strength (3.4-7.7% difference, all P < 0.05. This coincided with greater reductions in type IIX fibres from Week 0 to Week 12 (MOD, -4.6 percentage points; LOW -3.2 percentage points), greater phosphorylation of S6-kinase 1 (p85 S6K1Thr412 , 19%; p70 S6K1Thr389 , 58%) and ribosomal protein S6Ser235/236 (37%), greater rested-state total RNA (8.8%) and greater exercise-induced c-Myc mRNA expression (25%; Week 2, all P < 0.05). Thirteen and sixteen participants, respectively, displayed clear benefits in response to MOD on muscle hypertrophy and strength. Benefits were associated with greater accumulation of total RNA at Week 2 in the MOD leg, with every 1% difference increasing the odds of MOD benefit by 7.0% (P = 0.005) and 9.8% (P = 0.002). In conclusion, MOD led to greater functional and biological adaptations than LOW. Associations between dose-dependent total RNA accumulation and increases in muscle mass and strength point to ribosome biogenesis as a determinant of dose-dependent training responses.
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Affiliation(s)
- Daniel Hammarström
- Section for Health and Exercise Physiology, Department of Public Health and Sport Sciences, Inland Norway University of Applied Sciences, Elverum, Norway.,Swedish School of Sport and Health Sciences, Box 5626, SE-114 86, Stockholm, Sweden
| | - Sjur Øfsteng
- Section for Health and Exercise Physiology, Department of Public Health and Sport Sciences, Inland Norway University of Applied Sciences, Elverum, Norway
| | - Lise Koll
- Innlandet Hospital Trust, Postboks 990, 2629, Lillehammer, Norway
| | | | - Ivana Hollan
- Hospital for Rheumatic Diseases, Magrethe Grundtvigsvei 6, 2609, Lillehammer, Norway.,Brigham and Women's Hospital, 75 Francis Street, Boston, MA, 02115, USA
| | - William Apró
- Swedish School of Sport and Health Sciences, Box 5626, SE-114 86, Stockholm, Sweden
| | - Jon Elling Whist
- Innlandet Hospital Trust, Postboks 990, 2629, Lillehammer, Norway
| | - Eva Blomstrand
- Swedish School of Sport and Health Sciences, Box 5626, SE-114 86, Stockholm, Sweden
| | - Bent R Rønnestad
- Section for Health and Exercise Physiology, Department of Public Health and Sport Sciences, Inland Norway University of Applied Sciences, Elverum, Norway
| | - Stian Ellefsen
- Section for Health and Exercise Physiology, Department of Public Health and Sport Sciences, Inland Norway University of Applied Sciences, Elverum, Norway.,Innlandet Hospital Trust, Postboks 990, 2629, Lillehammer, Norway
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33
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Figueiredo VC, Englund DA, Vechetti IJ, Alimov A, Peterson CA, McCarthy JJ. Phosphorylation of eukaryotic initiation factor 4E is dispensable for skeletal muscle hypertrophy. Am J Physiol Cell Physiol 2019; 317:C1247-C1255. [PMID: 31596607 PMCID: PMC6962521 DOI: 10.1152/ajpcell.00380.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 10/09/2019] [Accepted: 10/09/2019] [Indexed: 11/22/2022]
Abstract
The eukaryotic initiation factor 4E (eIF4E) is a major mRNA cap-binding protein that has a central role in translation initiation. Ser209 is the single phosphorylation site within eIF4E and modulates its activity in response to MAPK pathway activation. It has been reported that phosphorylation of eIF4E at Ser209 promotes translation of key mRNAs, such as cyclin D1, that regulate ribosome biogenesis. We hypothesized that phosphorylation at Ser209 is required for skeletal muscle growth in response to a hypertrophic stimulus by promoting ribosome biogenesis. To test this hypothesis, wild-type (WT) and eIF4E knocked-in (KI) mice were subjected to synergist ablation to induce muscle hypertrophy of the plantaris muscle as the result of mechanical overload; in the KI mouse, Ser209 of eIF4E was replaced with a nonphosphorylatable alanine. Contrary to our hypothesis, we observed no difference in the magnitude of hypertrophy between WT and KI groups in response to 14 days of mechanical overload induced by synergist ablation. Similarly, the increases in cyclin D1 protein levels, ribosome biogenesis, and translational capacity did not differ between WT and KI groups. Based on these findings, we conclude that phosphorylation of eIF4E at Ser209 is dispensable for skeletal muscle hypertrophy in response to mechanical overload.
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Affiliation(s)
- Vandre C Figueiredo
- Department of Rehabilitation Sciences, College of Health Sciences, University of Kentucky, Lexington, Kentucky
- Center for Muscle Biology, University of Kentucky, Lexington, Kentucky
| | - Davis A Englund
- Department of Rehabilitation Sciences, College of Health Sciences, University of Kentucky, Lexington, Kentucky
- Center for Muscle Biology, University of Kentucky, Lexington, Kentucky
| | - Ivan J Vechetti
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky
- Center for Muscle Biology, University of Kentucky, Lexington, Kentucky
| | - Alexander Alimov
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky
- Center for Muscle Biology, University of Kentucky, Lexington, Kentucky
| | - Charlotte A Peterson
- Department of Rehabilitation Sciences, College of Health Sciences, University of Kentucky, Lexington, Kentucky
- Center for Muscle Biology, University of Kentucky, Lexington, Kentucky
| | - John J McCarthy
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky
- Center for Muscle Biology, University of Kentucky, Lexington, Kentucky
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34
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Chaillou T. Ribosome specialization and its potential role in the control of protein translation and skeletal muscle size. J Appl Physiol (1985) 2019; 127:599-607. [DOI: 10.1152/japplphysiol.00946.2018] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The ribosome is typically viewed as a supramolecular complex with constitutive and invariant capacity in mediating translation of mRNA into protein. This view has been challenged by recent research revealing that ribosome composition could be heterogeneous, and this heterogeneity leads to functional ribosome specialization. This review presents the idea that ribosome heterogeneity results from changes in its various components, including variations in ribosomal protein (RP) composition, posttranslational modifications of RPs, changes in ribosomal-associated proteins, alternative forms of rRNA, and posttranscriptional modifications of rRNAs. Ribosome heterogeneity could be orchestrated at several levels and may depend on numerous factors, such as the subcellular location, cell type, tissue specificity, the development state, cell state, ribosome biogenesis, RP turnover, physiological stimuli, and circadian rhythm. Ribosome specialization represents a completely new concept for the regulation of gene expression. Specialized ribosomes could modulate several aspects of translational control, such as mRNA translation selectivity, translation initiation, translational fidelity, and translation elongation. Recent research indicates that the expression of Rpl3 is markedly increased, while that of Rpl3l is highly reduced during mouse skeletal muscle hypertrophy. Moreover, Rpl3l overexpression impairs the growth and myogenic fusion of myotubes. Although the function of Rpl3 and Rpl3l in the ribosome remains to be clarified, these findings suggest that ribosome specialization may be potentially involved in the control of protein translation and skeletal muscle size. Limited data concerning ribosome specialization are currently available in skeletal muscle. Future investigations have the potential to delineate the function of specialized ribosomes in skeletal muscle.
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Affiliation(s)
- Thomas Chaillou
- School of Health Sciences, Örebro University, Örebro, Sweden
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35
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Impaired Ribosomal Biogenesis by Noncanonical Degradation of β-Catenin during Hyperammonemia. Mol Cell Biol 2019; 39:MCB.00451-18. [PMID: 31138664 DOI: 10.1128/mcb.00451-18] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 05/18/2019] [Indexed: 12/21/2022] Open
Abstract
Increased ribosomal biogenesis occurs during tissue hypertrophy, but whether ribosomal biogenesis is impaired during atrophy is not known. We show that hyperammonemia, which occurs in diverse chronic disorders, impairs protein synthesis as a result of decreased ribosomal content and translational capacity. Transcriptome analyses, real-time PCR, and immunoblotting showed consistent reductions in the expression of the large and small ribosomal protein subunits (RPL and RPS, respectively) in hyperammonemic murine skeletal myotubes, HEK cells, and skeletal muscle from hyperammonemic rats and human cirrhotics. Decreased ribosomal content was accompanied by decreased expression of cMYC, a positive regulator of ribosomal biogenesis, as well as reduced expression and activity of β-catenin, a transcriptional activator of cMYC. However, unlike the canonical regulation of β-catenin via glycogen synthase kinase 3β (GSK3β)-dependent degradation, GSK3β expression and phosphorylation were unaltered during hyperammonemia, and depletion of GSK3β did not prevent ammonia-induced degradation of β-catenin. Overexpression of GSK3β-resistant variants, genetic depletion of IκB kinase β (IKKβ) (activated during hyperammonemia), protein interactions, and in vitro kinase assays showed that IKKβ phosphorylated β-catenin directly. Overexpressing β-catenin restored hyperammonemia-induced perturbations in signaling responses that regulate ribosomal biogenesis. Our data show that decreased protein synthesis during hyperammonemia is mediated via a novel GSK3β-independent, IKKβ-dependent impairment of the β-catenin-cMYC axis.
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36
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Hansson B, Olsen LA, Nicoll JX, von Walden F, Melin M, Strömberg A, Rullman E, Gustafsson T, Fry AC, Fernandez-Gonzalo R, Lundberg TR. Skeletal muscle signaling responses to resistance exercise of the elbow extensors are not compromised by a preceding bout of aerobic exercise. Am J Physiol Regul Integr Comp Physiol 2019; 317:R83-R92. [DOI: 10.1152/ajpregu.00022.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The current study examined the effects of a preceding bout of aerobic exercise (AE) on subsequent molecular signaling to resistance exercise (RE) of the elbow extensors. Eleven men performed unilateral elbow-extensor AE (~45 min at 70% peak workload) followed by unilateral RE (4 × 7 maximal repetitions) for both arms. Thus, one arm performed AE+RE interspersed with 15 min recovery, whereas the other arm conducted RE alone. Muscle biopsies were taken from the triceps brachii of each arm immediately before (PRE) and 15 min (POST1) and 3 h (POST2) after RE. Molecular markers involved in translation initiation, protein breakdown, mechanosignaling, and ribosome biogenesis were analyzed. Peak power during RE was reduced by 24% (±19%) when preceded by AE ( P < 0.05). Increases in PGC1a and MuRF1 expression were greater from PRE to POST2 in AE+RE compared with RE (18- vs. 3.5- and 4- vs. 2-fold, respectively, interaction, P < 0.05). Myostatin mRNA decreased in both arms ( P < 0.05). Phosphorylation of AMPK (Thr172) increased (2.5-fold), and 4E-BP1 (Thr37/46) decreased (2.0-fold), after AE (interactions, P < 0.05). p70 S6K, yes-associated protein, and c-Jun NH2-terminal kinase phosphorylation were unaltered, whereas focal adhesion kinase decreased ~1.5-fold, and β1-integrin increased ~1.3- to 1.5-fold, (time effect, P < 0.05). Abundance of 45S pre-ribosomal (r)RNA (internally transcribed spacer, ITS) decreased (~30%) after AE (interaction, P < 0.05), whereas CMYC mRNA was greater in AE+RE compared with RE (12-fold, P < 0.05). POLR1B abundance increased after both AE+RE and RE. All together, our results suggest that a single bout of AE leads to an immediate decrease in signaling for translation initiation and ribosome biogenesis. Yet, this did not translate into altered RE-induced signaling during the 3-h postexercise recovery period.
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Affiliation(s)
- Björn Hansson
- Division of Clinical Physiology, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
- Unit of Clinical Physiology, Karolinska University Hospital, Stockholm, Sweden
| | - Luke A. Olsen
- Department of Biomedical Sciences, University of Kansas Medical Center, Kansas City, Kansas
| | - Justin X. Nicoll
- Department of Kinesiology, California State University, Northridge, California
| | - Ferdinand von Walden
- Department of Women’s and Children’s Health, Karolinska Institutet, Stockholm, Sweden
| | - Michael Melin
- Division of Clinical Physiology, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
- Unit of Clinical Physiology, Karolinska University Hospital, Stockholm, Sweden
- Heart and Vascular Theme, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - Anna Strömberg
- Division of Clinical Physiology, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
- Unit of Clinical Physiology, Karolinska University Hospital, Stockholm, Sweden
| | - Eric Rullman
- Division of Clinical Physiology, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
- Unit of Clinical Physiology, Karolinska University Hospital, Stockholm, Sweden
- Heart and Vascular Theme, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - Thomas Gustafsson
- Division of Clinical Physiology, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
- Unit of Clinical Physiology, Karolinska University Hospital, Stockholm, Sweden
| | - Andrew C. Fry
- Osness Human Performance Laboratories, University of Kansas, Lawrence, Kansas
| | - Rodrigo Fernandez-Gonzalo
- Division of Clinical Physiology, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
- Unit of Clinical Physiology, Karolinska University Hospital, Stockholm, Sweden
| | - Tommy R. Lundberg
- Division of Clinical Physiology, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
- Unit of Clinical Physiology, Karolinska University Hospital, Stockholm, Sweden
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37
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von Walden F. Ribosome biogenesis in skeletal muscle: coordination of transcription and translation. J Appl Physiol (1985) 2019; 127:591-598. [PMID: 31219775 DOI: 10.1152/japplphysiol.00963.2018] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Skeletal muscle mass responds in a remarkable manner to alterations in loading and use. It has long been clear that skeletal muscle hypertrophy can be prevented by inhibiting RNA synthesis. Since 80% of the cell's total RNA has been estimated to be rRNA, this finding indicates that de novo production of rRNA via transcription of the corresponding genes is important for such hypertrophy to occur. Transcription of rDNA by RNA Pol I is the rate-limiting step in ribosome biogenesis, indicating in turn that this biogenesis strongly influences the hypertrophic response. The present minireview focuses on 1) a brief description of the key steps in ribosome biogenesis and the relationship of this process to skeletal muscle mass and 2) the coordination of ribosome biogenesis and protein synthesis for growth or atrophy, as exemplified by the intracellular AMPK and mTOR pathways.
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Affiliation(s)
- Ferdinand von Walden
- Division of Pediatric Neurology, Department of Women's and Children's Health, Karolinska Institute, Stockholm, Sweden
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38
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Kotani T, Takegaki J, Takagi R, Nakazato K, Ishii N. Consecutive bouts of electrical stimulation-induced contractions alter ribosome biogenesis in rat skeletal muscle. J Appl Physiol (1985) 2019; 126:1673-1680. [DOI: 10.1152/japplphysiol.00665.2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ribosome biogenesis has been implicated in resistance exercise training (RET)-induced skeletal muscle hypertrophy. However, it is unclear how increasing bouts of RET affects ribosome content and biogenesis. This was investigated in the present study using simulated RET where rat skeletal muscle is subjected to increasing bouts of electrical stimulation. Sprague-Dawley rats were randomly assigned to the following seven groups: sedentary for 5 days (SED) or 6 wk (SED_6w), resistance-exercise trained with 1 bout (1B), 2 bouts (2B), 3 bouts (3B), 6 bouts (6B), and 18 bouts (18B). RET was simulated on the right gastrocnemius muscle by transcutaneous electric stimulation under isoflurane anesthesia, and a RET bout was given 3 times a week. Rats in 1B, 2B, and 3B groups showed increased 45S precursor (pre-) rRNA and 18S+28S rRNA content per muscle weight and elevated mRNA levels of c- myc and upstream binding factor (UBF). Increases in phosphorylated UBF and total cyclin D1 protein level were observed 48 h after RET; the former increased as a function of RET duration. In 3B, 6B, and 18B groups, the 18S+28S rRNA content per muscle weight was kept unchanged, and 45S pre-rRNA, cyclin D1, and phosphorylated UBF levels in 18B were lower than those in 3B. These results suggest that RET activates ribosome biogenesis and increases ribosome content through modulation of UBF and cyclin D1 activity at its early phase. Additional bouts of RET may not lead to a further increase in ribosome content per muscle weight through possibly the attenuation of transcription process. NEW & NOTEWORTHY Ribosome biogenesis has been implicated in resistance exercise training-induced skeletal muscle hypertrophy. However, it remains unclear how this is influenced by the volume of repeated bouts of resistance exercise training. Using resistance exercise training model with rat skeletal muscle, we provide evidence that ribosome biogenesis is stimulated by the initial few bouts of resistance exercise training with no additional effect of further increase in the exercise bout.
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Affiliation(s)
- Takaya Kotani
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
| | - Junya Takegaki
- Ritsumeikan Global Innovation Research Organization, Ritsumeikan University, Shiga, Japan
| | - Ryo Takagi
- Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan
| | - Koichi Nakazato
- Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan
| | - Naokata Ishii
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
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39
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Parry HA, Mobley CB, Mumford PW, Romero MA, Haun CT, Zhang Y, Roberson PA, Zempleni J, Ferrando AA, Vechetti IJ, McCarthy JJ, Young KC, Roberts MD, Kavazis AN. Bovine Milk Extracellular Vesicles (EVs) Modification Elicits Skeletal Muscle Growth in Rats. Front Physiol 2019; 10:436. [PMID: 31040795 PMCID: PMC6476979 DOI: 10.3389/fphys.2019.00436] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 03/29/2019] [Indexed: 12/12/2022] Open
Abstract
The current study investigated how bovine milk extracellular vesicles (EVs) affected rotarod performance and biomarkers of skeletal muscle physiology in young, growing rats. Twenty-eight-day Fisher 344 rats were provided an AIN-93G-based diet for 4 weeks that either remained unadulterated [EVs and RNA-sufficient (ERS; n = 12)] or was sonicated [EVs and RNA-depleted (ERD; n = 12)]. Prior to (PRE) and on the last day of the intervention (POST), animals were tested for maximal rotarod performance. Following the feeding period, the gastrocnemius muscle was analyzed at the histological, biochemical, and molecular levels and was also used to measure mitochondrial function and reactive oxygen species (ROS) emission. A main effect of time was observed for rotarod time (PRE > POST, p = 0.001). Terminal gastrocnemius mass was unaffected by diet, although gastrocnemius muscle fiber cross sectional area was 11% greater (p = 0.018) and total RNA (a surrogate of ribosome density) was 24% greater (p = 0.001) in ERD. Transcriptomic analysis of the gastrocnemius indicated that 22 mRNAs were significantly greater in ERS versus ERD (p < 0.01), whereas 55 mRNAs were greater in ERD versus ERS (p < 0.01). There were no differences in gastrocnemius citrate synthase activity or mitochondrial coupling (respiratory control ratio), although mitochondrial ROS production was lower in ERD gastrocnemius (p = 0.016), which may be explained by an increase in glutathione peroxidase protein levels (p = 0.020) in ERD gastrocnemius. Dietary EVs profiling confirmed that sonication in the ERD diet reduced EVs content by ∼60%. Our findings demonstrate that bovine milk EVs depletion through sonication elicits anabolic and transcriptomic effects in the gastrocnemius muscle of rapidly maturing rats. While this did not translate into a functional outcome between diets (i.e., rotarod performance), longer feeding periods may be needed to observe such functional effects.
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Affiliation(s)
- Hailey A. Parry
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | - C. Brooks Mobley
- School of Kinesiology, Auburn University, Auburn, AL, United States
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY, United States
| | - Petey W. Mumford
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | | | - Cody T. Haun
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | - Yufeng Zhang
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | - Paul A. Roberson
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | - Janos Zempleni
- Department of Nutrition and Health Sciences, University of Nebraska–Lincoln, Lincoln, NE, United States
| | - Arny A. Ferrando
- Donald W. Reynolds Institute on Aging, University of Arkansas for Medical Sciences, Little Rock, AK, United States
| | - Ivan J. Vechetti
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY, United States
| | - John J. McCarthy
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY, United States
| | - Kaelin C. Young
- School of Kinesiology, Auburn University, Auburn, AL, United States
- Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine-Auburn Campus, Auburn, AL, United States
| | - Michael D. Roberts
- School of Kinesiology, Auburn University, Auburn, AL, United States
- Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine-Auburn Campus, Auburn, AL, United States
| | - Andreas N. Kavazis
- School of Kinesiology, Auburn University, Auburn, AL, United States
- Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine-Auburn Campus, Auburn, AL, United States
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Kim HG, Guo B, Nader GA. Regulation of Ribosome Biogenesis During Skeletal Muscle Hypertrophy. Exerc Sport Sci Rev 2019; 47:91-97. [DOI: 10.1249/jes.0000000000000179] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Rantala R, Chaillou T. Mild hypothermia affects the morphology and impairs glutamine-induced anabolic response in human primary myotubes. Am J Physiol Cell Physiol 2019; 317:C101-C110. [PMID: 30917033 DOI: 10.1152/ajpcell.00008.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The specific impact of reduced temperature on skeletal muscle adaptation has been poorly investigated. Cold water immersion, one situation leading to decreased skeletal muscle temperature, is commonly proposed to reduce the perception of fatigue and muscle soreness after strenuous exercise. In contrast, it may impair long-term benefits of resistance exercise training on muscle strength and hypertrophy. To date, the physiological factors responsible for this blunted muscle adaptation remain unclear. Here, we used a cell culture model of human primary myotubes to specifically investigate the intrinsic behavior of muscle cells during mild hypothermia (MH). Newly formed myotubes were exposed to either 37°C or 32°C to evaluate the effect of MH on myotube size and morphology, protein synthesis, and anabolic signaling. We also compared the glutamine (GLUT)-induced hypertrophic response between myotubes incubated at 32°C or 37°C. We showed that 48 h exposure to MH altered the cellular morphology (greater myotube area, shorter myosegments, myotubes with irregular shape) and impaired GLUT-induced myotube hypertrophy. Moreover, MH specifically reduced protein synthesis at 8 h. This result may be explained by an altered regulation of ribosome biogenesis, as evidenced by a lower expression of 45S pre-ribosomal RNA and MYC protein, and a lower total RNA concentration. Furthermore, MH blunted GLUT-induced increase in protein synthesis at 8 h, a finding consistent with an impaired activation of the mechanistic target of rapamycin pathway. In conclusion, this study demonstrates that MH impairs the morphology of human myotubes and alters the hypertrophic response to GLUT.
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Affiliation(s)
- Robert Rantala
- Department of Health Sciences, Örebro University, Orebro, Sweden
| | - Thomas Chaillou
- Department of Health Sciences, Örebro University, Orebro, Sweden
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Haun CT, Vann CG, Mobley CB, Osburn SC, Mumford PW, Roberson PA, Romero MA, Fox CD, Parry HA, Kavazis AN, Moon JR, Young KC, Roberts MD. Pre-training Skeletal Muscle Fiber Size and Predominant Fiber Type Best Predict Hypertrophic Responses to 6 Weeks of Resistance Training in Previously Trained Young Men. Front Physiol 2019; 10:297. [PMID: 30971942 PMCID: PMC6445136 DOI: 10.3389/fphys.2019.00297] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 03/06/2019] [Indexed: 12/24/2022] Open
Abstract
Limited evidence exists regarding differentially expressed biomarkers between previously-trained low versus high hypertrophic responders in response to resistance training. Herein, 30 college-aged males (training age 5 ± 3 years; mean ± SD) partook in 6 weeks of high-volume resistance training. Body composition, right leg vastus lateralis (VL) biopsies, and blood were obtained prior to training (PRE) and at the 3-week (W3) and 6-week time points (W6). The 10 lowest (LOW) and 10 highest (HIGH) hypertrophic responders were clustered based upon a composite hypertrophy score of PRE-to-W6 changes in right leg VL mean muscle fiber cross-sectional area (fCSA), VL thickness assessed via ultrasound, upper right leg lean soft tissue mass assessed via dual x-ray absorptiometry (DXA), and mid-thigh circumference. Two-way ANOVAs were used to compare biomarker differences between the LOW and HIGH clusters over time, and stepwise linear regression was performed to elucidate biomarkers that explained significant variation in the composite hypertrophy score from PRE to W3, W3 to W6, and PRE to W6 in all 30 participants. PRE-to-W6 HIGH and LOW responders exhibited a composite hypertrophy change of +10.7 ± 3.2 and -2.1 ± 1.6%, respectively (p < 0.001). Compared to HIGH responders, LOW responders exhibited greater PRE type II fCSA (+18%, p = 0.022). Time effects (p < 0.05) existed for total RNA/mg muscle (W6 > W3 > PRE), phospho (p)-4EBP1 (PRE > W3&W6), pan-mTOR (PRE > W3 < W6), p-mTOR (PRE > W3 < W6), pan-AMPKα (PRE > W3 < W6), pan-p70s6k (PRE > W3), muscle ubiquitin-labeled proteins (PRE > W6), mechano growth factor mRNA (W6 > W3&PRE), 45S rRNA (PRE > W6), and muscle citrate synthase activity (PRE > W3&W6). No interactions existed for the aforementioned biomarkers and/or other assayed targets (muscle 20S proteasome activity, serum total testosterone, muscle androgen receptor protein levels, muscle glycogen, or serum creatine kinase). Regression analysis indicated PRE type II fiber percentage (R2 = 0.152, β = 0.390, p = 0.033) and PRE type II fCSA (R2 = 0.207, β = -0.455, p = 0.019) best predicted the PRE-to-W6 change in the composite hypertrophy score. While our sample size is limited, these data suggest: (a) HIGH responders may exhibit more growth potential given that they possessed lower PRE type II fCSA values and (b) possessing a greater type II fiber percentage as a trained individual may be advantageous for hypertrophy in response to resistance training.
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Affiliation(s)
- Cody T Haun
- School of Kinesiology, Auburn University, Auburn, AL, United States.,Department of Exercise Science, LaGrange College, LaGrange, GA, United States
| | | | - C Brooks Mobley
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | - Shelby C Osburn
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | - Petey W Mumford
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | - Paul A Roberson
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | - Matthew A Romero
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | - Carlton D Fox
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | - Hailey A Parry
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | | | | | - Kaelin C Young
- School of Kinesiology, Auburn University, Auburn, AL, United States.,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine - Auburn Campus, Auburn, AL, United States
| | - Michael D Roberts
- School of Kinesiology, Auburn University, Auburn, AL, United States.,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine - Auburn Campus, Auburn, AL, United States
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Bakshi A, Moin M, Madhav MS, Kirti PB. Target of rapamycin, a master regulator of multiple signalling pathways and a potential candidate gene for crop improvement. PLANT BIOLOGY (STUTTGART, GERMANY) 2019; 21:190-205. [PMID: 30411830 DOI: 10.1111/plb.12935] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 11/05/2018] [Indexed: 06/08/2023]
Abstract
The target of rapamycin (TOR) protein regulates growth and development in photosynthetic and non-photosynthetic eukaryotes. Although the TOR regulatory networks are involved in nutrient and energy signalling, and transcriptional and translational control of multiple signalling pathways, the molecular mechanism of TOR regulation of plant abiotic stress responses is still unclear. The TOR-mediated transcriptional regulation of genes encoding ribosomal proteins (RP) is a necessity under stress conditions for balanced growth and productivity in plants. The activation of SnRKs (sucrose non-fermenting-related kinases) and the inactivation of TOR signalling in abiotic stresses is in line with the accumulation of ABA and transcriptional activation of stress responsive genes. Autophagy is induced under abiotic stress conditions, which results in degradation of proteins and the release of amino acids, which might possibly induce phosphorylation of TOR and, hence, its activation. TOR signalling also has a role in regulating ABA biosynthesis for transcriptional regulation of stress-related genes. The switch between activation and inactivation of TOR by its phosphorylation and de-phosphorylation maintains balanced growth in response to stresses. In the present review, we discuss the important signalling pathways that are regulated by TOR and try to assess the relationship between TOR signalling and tolerance to abiotic stresses in plants. The review also discusses possible cross-talk between TOR and RP genes in response to abiotic stresses.
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Affiliation(s)
- A Bakshi
- Department of Plant Sciences, University of Hyderabad, Hyderabad, India
| | - M Moin
- Department of Biotechnology, Indian Institute of Rice Research, Hyderabad, India
| | - M S Madhav
- Department of Biotechnology, Indian Institute of Rice Research, Hyderabad, India
| | - P B Kirti
- Department of Plant Sciences, University of Hyderabad, Hyderabad, India
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Sciascia QL, van der Linden DS, Sales FA, Wards NJ, Blair HT, Pacheco D, Oliver MH, McCoard SA. Parenteral administration of l-arginine to twin-bearing Romney ewes during late pregnancy is associated with reduced milk somatic cell count during early lactation. J Dairy Sci 2019; 102:3071-3081. [PMID: 30712927 DOI: 10.3168/jds.2018-15433] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 11/30/2018] [Indexed: 11/19/2022]
Abstract
Maternal milk is the primary source of nutrition for suckling mammals, and its yield and composition are important determinants of survival during the early neonatal period. The objective of this study was to examine whether parenteral administration of l-Arg to twin-bearing ewes, during mid to late pregnancy, influenced prepartum maternal mammary gland development and subsequent lactation performance in the early postpartum period (14 d). At 80 d of pregnancy, multiparous Romney ewes were housed indoors in group pens, split into 2 cohorts, and fed a lucerne-based pellet diet, formulated to meet 100% of National Research Council-recommended requirements for twin-bearing pregnant ewes, once a day. Cohort 1 was administered l-Arg (72.7 mg/kg of live weight via i.v, 3 times a day) from d 100 of pregnancy until d 140. At d 140, ewes were euthanized and maternal mammary tissues were collected for analysis of the biochemical indices total DNA, RNA, protein, protein synthetic efficiency (protein:RNA), cell size (protein:DNA), transcriptional efficiency (RNA:DNA), and the abundance of mammalian target of rapamycin (mTOR) and mTORSer2448 protein. Cohort 2 was administered an identical l-Arg regimen as cohort 1, but from d 100 until parturition. Milk was collected over a 14-d period (d 1, 4, 7, 10, and 14) to assess milk yield and composition. In cohort 1, total mammary DNA (cell number) tended to be higher in l-Arg ewes, with no change in total mammary RNA or protein content, biochemical indices of protein synthetic efficiency, cell size or transcriptional efficiency, or mTOR protein abundance or phosphorylation. In cohort 2, milk composition analysis from l-Arg ewes showed lower (d 7-14) milk somatic cell counts, greater crude protein percentage from d 7 to 10 but lower at d 14, and altered absolute concentrations of some free AA (d 7 and 14) compared with controls. We propose that parenteral administration of l-Arg during late pregnancy is associated with increased mammary gland cellular content and decreased somatic cell counts during early lactation.
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Affiliation(s)
- Quentin L Sciascia
- AgResearch Grasslands, Palmerston North 4442, New Zealand; Gravida, National Centre for Growth and Development, University of Auckland, Auckland 1023, New Zealand
| | - Danitsja S van der Linden
- AgResearch Grasslands, Palmerston North 4442, New Zealand; Gravida, National Centre for Growth and Development, University of Auckland, Auckland 1023, New Zealand
| | - Francisco A Sales
- AgResearch Grasslands, Palmerston North 4442, New Zealand; Gravida, National Centre for Growth and Development, University of Auckland, Auckland 1023, New Zealand
| | - Nina J Wards
- AgResearch Grasslands, Palmerston North 4442, New Zealand
| | - Hugh T Blair
- Gravida, National Centre for Growth and Development, University of Auckland, Auckland 1023, New Zealand; International Sheep Research Centre, Massey University, Palmerston North 4442, New Zealand
| | - David Pacheco
- AgResearch Grasslands, Palmerston North 4442, New Zealand
| | - Mark H Oliver
- Gravida, National Centre for Growth and Development, University of Auckland, Auckland 1023, New Zealand; Ngapouri Research Farm, Liggins Institute, University of Auckland, Auckland 3083, New Zealand
| | - Susan A McCoard
- AgResearch Grasslands, Palmerston North 4442, New Zealand; Gravida, National Centre for Growth and Development, University of Auckland, Auckland 1023, New Zealand.
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Figueiredo VC, McCarthy JJ. Regulation of Ribosome Biogenesis in Skeletal Muscle Hypertrophy. Physiology (Bethesda) 2019; 34:30-42. [PMID: 30540235 PMCID: PMC6383632 DOI: 10.1152/physiol.00034.2018] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 09/11/2018] [Accepted: 09/13/2018] [Indexed: 01/22/2023] Open
Abstract
The ribosome is the enzymatic macromolecular machine responsible for protein synthesis. The rates of protein synthesis are primarily dependent on translational efficiency and capacity. Ribosome biogenesis has emerged as an important regulator of skeletal muscle growth and maintenance by altering the translational capacity of the cell. Here, we provide evidence to support a central role for ribosome biogenesis in skeletal muscle growth during postnatal development and in response to resistance exercise training. Furthermore, we discuss the cellular signaling pathways regulating ribosome biogenesis, discuss how myonuclear accretion affects translational capacity, and explore future areas of investigation within the field.
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Affiliation(s)
- Vandré Casagrande Figueiredo
- The Center for Muscle Biology, College of Health Sciences, University of Kentucky , Lexington, Kentucky
- Department of Rehabilitation Sciences, College of Medicine, University of Kentucky , Lexington, Kentucky
| | - John J McCarthy
- The Center for Muscle Biology, College of Health Sciences, University of Kentucky , Lexington, Kentucky
- Department of Physiology, University of Kentucky , Lexington, Kentucky
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46
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Mirzoev TM, Shenkman BS. Regulation of Protein Synthesis in Inactivated Skeletal Muscle: Signal Inputs, Protein Kinase Cascades, and Ribosome Biogenesis. BIOCHEMISTRY (MOSCOW) 2018; 83:1299-1317. [PMID: 30482143 DOI: 10.1134/s0006297918110020] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Disuse atrophy of skeletal muscles is characterized by a significant decrease in the mass and size of muscle fibers. Disuse atrophy develops as a result of prolonged reduction in the muscle functional activity caused by bed rest, limb immobilization, and real or simulated microgravity. Disuse atrophy is associated with the downregulation of protein biosynthesis and simultaneous activation of protein degradation. This review is focused on the key molecular mechanisms regulating the rate of protein synthesis in mammalian skeletal muscles during functional unloading.
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Affiliation(s)
- T M Mirzoev
- Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, 123007, Russia.
| | - B S Shenkman
- Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, 123007, Russia
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Hornberger TA, Carter HN, Hood DA, Figueiredo VC, Dupont-Versteegden EE, Peterson CA, McCarthy JJ, Camera DM, Hawley JA, Chaillou T, Cheng AJ, Nader GA, Wüst RCI, Houtkooper RH. Commentaries on Viewpoint: The rigorous study of exercise adaptations: Why mRNA might not be enough. J Appl Physiol (1985) 2018; 121:597-600. [PMID: 27543661 DOI: 10.1152/japplphysiol.00509.2016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Affiliation(s)
- Troy A Hornberger
- University of Wisconsin-MadisonYork UniversityUniversity of KentuckyAustralian Catholic UniversityAustralian Catholic University, Liverpool John Moores UniversityKarolinska InstitutetPennsylvania State UniversityAcademic Medical Center, University of Amsterdam
| | - Heather N Carter
- University of Wisconsin-MadisonYork UniversityUniversity of KentuckyAustralian Catholic UniversityAustralian Catholic University, Liverpool John Moores UniversityKarolinska InstitutetPennsylvania State UniversityAcademic Medical Center, University of Amsterdam
| | - David A Hood
- University of Wisconsin-MadisonYork UniversityUniversity of KentuckyAustralian Catholic UniversityAustralian Catholic University, Liverpool John Moores UniversityKarolinska InstitutetPennsylvania State UniversityAcademic Medical Center, University of Amsterdam
| | - Vandré Casagrande Figueiredo
- University of Wisconsin-MadisonYork UniversityUniversity of KentuckyAustralian Catholic UniversityAustralian Catholic University, Liverpool John Moores UniversityKarolinska InstitutetPennsylvania State UniversityAcademic Medical Center, University of Amsterdam
| | - Esther E Dupont-Versteegden
- University of Wisconsin-MadisonYork UniversityUniversity of KentuckyAustralian Catholic UniversityAustralian Catholic University, Liverpool John Moores UniversityKarolinska InstitutetPennsylvania State UniversityAcademic Medical Center, University of Amsterdam
| | - Charlotte A Peterson
- University of Wisconsin-MadisonYork UniversityUniversity of KentuckyAustralian Catholic UniversityAustralian Catholic University, Liverpool John Moores UniversityKarolinska InstitutetPennsylvania State UniversityAcademic Medical Center, University of Amsterdam
| | - John J McCarthy
- University of Wisconsin-MadisonYork UniversityUniversity of KentuckyAustralian Catholic UniversityAustralian Catholic University, Liverpool John Moores UniversityKarolinska InstitutetPennsylvania State UniversityAcademic Medical Center, University of Amsterdam
| | - Donny M Camera
- University of Wisconsin-MadisonYork UniversityUniversity of KentuckyAustralian Catholic UniversityAustralian Catholic University, Liverpool John Moores UniversityKarolinska InstitutetPennsylvania State UniversityAcademic Medical Center, University of Amsterdam
| | - John A Hawley
- University of Wisconsin-MadisonYork UniversityUniversity of KentuckyAustralian Catholic UniversityAustralian Catholic University, Liverpool John Moores UniversityKarolinska InstitutetPennsylvania State UniversityAcademic Medical Center, University of Amsterdam
| | - Thomas Chaillou
- University of Wisconsin-MadisonYork UniversityUniversity of KentuckyAustralian Catholic UniversityAustralian Catholic University, Liverpool John Moores UniversityKarolinska InstitutetPennsylvania State UniversityAcademic Medical Center, University of Amsterdam
| | - Arthur J Cheng
- University of Wisconsin-MadisonYork UniversityUniversity of KentuckyAustralian Catholic UniversityAustralian Catholic University, Liverpool John Moores UniversityKarolinska InstitutetPennsylvania State UniversityAcademic Medical Center, University of Amsterdam
| | - Gustavo A Nader
- University of Wisconsin-MadisonYork UniversityUniversity of KentuckyAustralian Catholic UniversityAustralian Catholic University, Liverpool John Moores UniversityKarolinska InstitutetPennsylvania State UniversityAcademic Medical Center, University of Amsterdam
| | - Rob C I Wüst
- University of Wisconsin-MadisonYork UniversityUniversity of KentuckyAustralian Catholic UniversityAustralian Catholic University, Liverpool John Moores UniversityKarolinska InstitutetPennsylvania State UniversityAcademic Medical Center, University of Amsterdam
| | - Riekelt H Houtkooper
- University of Wisconsin-MadisonYork UniversityUniversity of KentuckyAustralian Catholic UniversityAustralian Catholic University, Liverpool John Moores UniversityKarolinska InstitutetPennsylvania State UniversityAcademic Medical Center, University of Amsterdam
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48
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Wen Y, Alimov AP, McCarthy JJ. Ribosome Biogenesis is Necessary for Skeletal Muscle Hypertrophy. Exerc Sport Sci Rev 2018; 44:110-5. [PMID: 27135313 DOI: 10.1249/jes.0000000000000082] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Yuan Wen
- 1Department of Physiology, 2Center for Muscle Biology, and 3College of Medicine, University of Kentucky, Lexington, KY
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49
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Roberts MD, Haun CT, Mobley CB, Mumford PW, Romero MA, Roberson PA, Vann CG, McCarthy JJ. Physiological Differences Between Low Versus High Skeletal Muscle Hypertrophic Responders to Resistance Exercise Training: Current Perspectives and Future Research Directions. Front Physiol 2018; 9:834. [PMID: 30022953 PMCID: PMC6039846 DOI: 10.3389/fphys.2018.00834] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 06/13/2018] [Indexed: 12/22/2022] Open
Abstract
Numerous reports suggest there are low and high skeletal muscle hypertrophic responders following weeks to months of structured resistance exercise training (referred to as low and high responders herein). Specifically, divergent alterations in muscle fiber cross sectional area (fCSA), vastus lateralis thickness, and whole body lean tissue mass have been shown to occur in high versus low responders. Differential responses in ribosome biogenesis and subsequent protein synthetic rates during training seemingly explain some of this individual variation in humans, and mechanistic in vitro and rodent studies provide further evidence that ribosome biogenesis is critical for muscle hypertrophy. High responders may experience a greater increase in satellite cell proliferation during training versus low responders. This phenomenon could serve to maintain an adequate myonuclear domain size or assist in extracellular remodeling to support myofiber growth. High responders may also express a muscle microRNA profile during training that enhances insulin-like growth factor-1 (IGF-1) mRNA expression, although more studies are needed to better validate this mechanism. Higher intramuscular androgen receptor protein content has been reported in high versus low responders following training, and this mechanism may enhance the hypertrophic effects of testosterone during training. While high responders likely possess “good genetics,” such evidence has been confined to single gene candidates which typically share marginal variance with hypertrophic outcomes following training (e.g., different myostatin and IGF-1 alleles). Limited evidence also suggests pre-training muscle fiber type composition and self-reported dietary habits (e.g., calorie and protein intake) do not differ between high versus low responders. Only a handful of studies have examined muscle biomarkers that are differentially expressed between low versus high responders. Thus, other molecular and physiological variables which could potentially affect the skeletal muscle hypertrophic response to resistance exercise training are also discussed including rDNA copy number, extracellular matrix and connective tissue properties, the inflammatory response to training, and mitochondrial as well as vascular characteristics.
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Affiliation(s)
| | - Cody T Haun
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | | | - Petey W Mumford
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | - Matthew A Romero
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | - Paul A Roberson
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | | | - John J McCarthy
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY, United States
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Takegaki J, Ogasawara R, Tamura Y, Takagi R, Arihara Y, Tsutaki A, Nakazato K, Ishii N. Repeated bouts of resistance exercise with short recovery periods activates mTOR signaling, but not protein synthesis, in mouse skeletal muscle. Physiol Rep 2018; 5:5/22/e13515. [PMID: 29180484 PMCID: PMC5704086 DOI: 10.14814/phy2.13515] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 10/31/2017] [Accepted: 11/01/2017] [Indexed: 11/24/2022] Open
Abstract
The recovery period between bouts of exercise is one of the major factors influencing the effects of resistance exercise, in addition to exercise intensity and volume. However, the effects of shortening the recovery time between bouts of resistance exercise on subsequent protein synthesis remain unclear. In this study, we investigated the consequences of shortening the recovery time between bouts of resistance exercise on protein synthesis and related processes in mouse skeletal muscles. Eighteen male C57BL/6J mice were randomly subjected to three bouts of resistance exercise with 72 (72H), 24 (24H), or 8 h (8H) of recovery periods between bouts. Resistance exercise, consisting of five sets of 3 s × 10 isometric contractions with 3 min rest between sets, was elicited on the right tibialis anterior muscle via percutaneous electrical stimulation on the deep peroneal nerve under isoflurane anesthesia. The left muscle served as an internal control. Six hours after the third bout of exercise, protein synthesis was found to be activated in the 72H and 24H groups, but not in the 8H group. Phosphorylation of p70S6K at Thr 389, a marker of mammalian target of rapamycin (mTOR) signaling, was increased in all groups, with the 8H group showing the highest magnitude. In contrast, protein carbonylation was observed only in mice in the 8H group. These results suggest that repeated bouts of resistance exercise with 8 h of recovery periods do not effectively increase the levels of muscle protein synthesis despite activation of the mTOR signaling pathway, which likely involves oxidative stress.
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Affiliation(s)
- Junya Takegaki
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
| | - Riki Ogasawara
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Nagoya, Japan
| | - Yuki Tamura
- Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan
| | - Ryo Takagi
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
| | - Yuki Arihara
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
| | - Arata Tsutaki
- Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan
| | - Koichi Nakazato
- Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan
| | - Naokata Ishii
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
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