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Fowler A, Knaus KR, Khuu S, Khalilimeybodi A, Schenk S, Ward SR, Fry AC, Rangamani P, McCulloch AD. Network model of skeletal muscle cell signalling predicts differential responses to endurance and resistance exercise training. Exp Physiol 2024; 109:939-955. [PMID: 38643471 PMCID: PMC11140181 DOI: 10.1113/ep091712] [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: 12/06/2023] [Accepted: 03/20/2024] [Indexed: 04/22/2024]
Abstract
Exercise-induced muscle adaptations vary based on exercise modality and intensity. We constructed a signalling network model from 87 published studies of human or rodent skeletal muscle cell responses to endurance or resistance exercise in vivo or simulated exercise in vitro. The network comprises 259 signalling interactions between 120 nodes, representing eight membrane receptors and eight canonical signalling pathways regulating 14 transcriptional regulators, 28 target genes and 12 exercise-induced phenotypes. Using this network, we formulated a logic-based ordinary differential equation model predicting time-dependent molecular and phenotypic alterations following acute endurance and resistance exercises. Compared with nine independent studies, the model accurately predicted 18/21 (85%) acute responses to resistance exercise and 12/16 (75%) acute responses to endurance exercise. Detailed sensitivity analysis of differential phenotypic responses to resistance and endurance training showed that, in the model, exercise regulates cell growth and protein synthesis primarily by signalling via mechanistic target of rapamycin, which is activated by Akt and inhibited in endurance exercise by AMP-activated protein kinase. Endurance exercise preferentially activates inflammation via reactive oxygen species and nuclear factor κB signalling. Furthermore, the expected preferential activation of mitochondrial biogenesis by endurance exercise was counterbalanced in the model by protein kinase C in response to resistance training. This model provides a new tool for investigating cross-talk between skeletal muscle signalling pathways activated by endurance and resistance exercise, and the mechanisms of interactions such as the interference effects of endurance training on resistance exercise outcomes.
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Affiliation(s)
- Annabelle Fowler
- Department of BioengineeringUniversity of California SanDiegoLa JollaCaliforniaUSA
| | - Katherine R. Knaus
- Department of BioengineeringUniversity of California SanDiegoLa JollaCaliforniaUSA
| | - Stephanie Khuu
- Department of BioengineeringUniversity of California SanDiegoLa JollaCaliforniaUSA
| | - Ali Khalilimeybodi
- Department of Mechanical and Aerospace EngineeringUniversity of California San DiegoLa JollaCaliforniaUSA
| | - Simon Schenk
- Department of Orthopaedic SurgeryUniversity of California San DiegoLa JollaCaliforniaUSA
| | - Samuel R. Ward
- Department of Orthopaedic SurgeryUniversity of California San DiegoLa JollaCaliforniaUSA
| | - Andrew C. Fry
- Department of Health, Sport and Exercise SciencesUniversity of KansasLawrenceKansasUSA
| | - Padmini Rangamani
- Department of Mechanical and Aerospace EngineeringUniversity of California San DiegoLa JollaCaliforniaUSA
| | - Andrew D. McCulloch
- Department of BioengineeringUniversity of California SanDiegoLa JollaCaliforniaUSA
- Department of MedicineUniversity of California San DiegoLa JollaCaliforniaUSA
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Hesketh SJ. Advancing cancer cachexia diagnosis with -omics technology and exercise as molecular medicine. SPORTS MEDICINE AND HEALTH SCIENCE 2024; 6:1-15. [PMID: 38463663 PMCID: PMC10918365 DOI: 10.1016/j.smhs.2024.01.006] [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: 09/21/2023] [Revised: 01/15/2024] [Accepted: 01/20/2024] [Indexed: 03/12/2024] Open
Abstract
Muscle atrophy exacerbates disease outcomes and increases mortality, whereas the preservation of skeletal muscle mass and function play pivotal roles in ensuring long-term health and overall quality-of-life. Muscle atrophy represents a significant clinical challenge, involving the continued loss of muscle mass and strength, which frequently accompany the development of numerous types of cancer. Cancer cachexia is a highly prevalent multifactorial syndrome, and although cachexia is one of the main causes of cancer-related deaths, there are still no approved management strategies for the disease. The etiology of this condition is based on the upregulation of systemic inflammation factors and catabolic stimuli, resulting in the inhibition of protein synthesis and enhancement of protein degradation. Numerous necessary cellular processes are disrupted by cachectic pathology, which mediate intracellular signalling pathways resulting in the net loss of muscle and organelles. However, the exact underpinning molecular mechanisms of how these changes are orchestrated are incompletely understood. Much work is still required, but structured exercise has the capacity to counteract numerous detrimental effects linked to cancer cachexia. Primarily through the stimulation of muscle protein synthesis, enhancement of mitochondrial function, and the release of myokines. As a result, muscle mass and strength increase, leading to improved mobility, and quality-of-life. This review summarises existing knowledge of the complex molecular networks that regulate cancer cachexia and exercise, highlighting the molecular interplay between the two for potential therapeutic intervention. Finally, the utility of mass spectrometry-based proteomics is considered as a way of establishing early diagnostic biomarkers of cachectic patients.
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Hasan I, Rainsford KD, Ross JS. Salsalate: a pleotropic anti-inflammatory drug in the treatment of diabetes, obesity, and metabolic diseases. Inflammopharmacology 2023; 31:2781-2797. [PMID: 37758933 DOI: 10.1007/s10787-023-01242-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 04/12/2023] [Indexed: 09/29/2023]
Abstract
Type two Diabetes Mellitus (T2DM) is a rising epidemic. Available therapeutic strategies have provided glycaemic control via HbA1c reduction but fail to provide clinically meaningful reduction in microvascular and macrovascular (cardiac, renal, ophthalmological, and neurological) complications. Inflammation is strongly linked to the pathogenesis of T2DM. Underlying inflammatory mechanisms include oxidative stress, endoplasmic reticulum stress amyloid deposition in the pancreas, lipotoxicity, and glucotoxicity. Molecular signalling mechanisms in chronic inflammation linked to obesity and diabetes include JANK, NF-kB, and AMPK pathways. These activated pathways lead to a production of various inflammatory cytokines, such as Interleukin (IL-6), tumor necrosis factor (TNF)-alpha, and C-reactive protein (CRP), which create a chronic low-grade inflammation and ultimately dysregulation of glucose homeostasis in the liver, skeletal muscle, and smooth muscle. Anti-inflammatory agents are being tested as anti-diabetic agents such as the IL-1b antagonist, Anakinra, the IL-1b inhibitor, Canakinuma, the IL-6 antagonists such as Tocilizumab, Rapamycin (Everolimus), and the IKK-beta kinase inhibitor, Salsalate. Salsalate is a century old safe anti-inflammatory drug used in the treatment of arthritis. Long-term safety and efficacy of Salsalate in the treatment of T2DM have been evaluated, which showed improved fasting plasma glucose and reduced HbA1C levels as well as reduced pro-inflammatory markers in T2DM patients. Current publication summarizes the literature review of pathophysiology of role of inflammation in T2DM and clinical efficacy and safety of Salsalate in the treatment of T2DM.
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Affiliation(s)
- I Hasan
- RH Nanopharmaceuticals LLC, 140 Ocean Ave, Monmouth Beach, New Jersey, 07750, USA.
| | - K D Rainsford
- Emeritus Professor of Biomedical Sciences, Department of Biosciences and Chemistry, BMRC, Sheffield Hallam University, Howard Street, Sheffield, S1 1WB, UK
| | - Joel S Ross
- RH Nanopharmaceuticals LLC, 140 Ocean Ave, Monmouth Beach, New Jersey, 07750, USA
- J & D Pharmaceuticals LLC, Monmouth County, USA
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4
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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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Mirzoev TM. The emerging role of Piezo1 channels in skeletal muscle physiology. Biophys Rev 2023; 15:1171-1184. [PMID: 37975010 PMCID: PMC10643716 DOI: 10.1007/s12551-023-01154-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 09/25/2023] [Indexed: 11/19/2023] Open
Abstract
Piezo1 channels are mechanically activated (MA) cation channels that are involved in sensing of various mechanical perturbations, such as membrane stretch and shear stress, and play a crucial role in cell mechanotransduction. In response to mechanical stimuli, these channels open up and allow cations to travel into the cell and induce biochemical reactions that can change the cell's metabolism and function. Skeletal muscle cells/fibers inherently depend upon mechanical cues in the form of fluid shear stress and contractions (physical exercise). For example, an exposure of skeletal muscles to chronic mechanical loading leads to increased anabolism and fiber hypertrophy, while prolonged mechanical unloading results in muscle atrophy. MA Piezo1 channels have recently emerged as key mechanosensors that are capable of linking mechanical signals and intramuscular signaling in skeletal muscle cells/fibers. This review will summarize the emerging role of Piezo1 channels in the development and regeneration of skeletal muscle tissue as well as in the regulation of skeletal muscle atrophy. In addition, an overview of potential Piezo1-related signaling pathways underlying anabolic and catabolic processes will be provided. A better understanding of Piezo1's role in skeletal muscle mechanotransduction may represent an important basis for the development of therapeutic strategies for maintaining muscle functions under disuse conditions and in some disease states.
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Affiliation(s)
- Timur M. Mirzoev
- Myology Laboratory, Institute of Biomedical Problems RAS, Moscow, Russia
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Lyu W, Kousaka M, Jia H, Kato H. Effects of Turmeric Extract on Age-Related Skeletal Muscle Atrophy in Senescence-Accelerated Mice. Life (Basel) 2023; 13:life13040941. [PMID: 37109470 PMCID: PMC10141758 DOI: 10.3390/life13040941] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 03/14/2023] [Accepted: 03/31/2023] [Indexed: 04/07/2023] Open
Abstract
Muscle atrophy is one of the main causes of sarcopenia—the age-related loss of skeletal muscle. In this study, we investigated the effect of turmeric (Curcuma longa) extract (TE) supplementation on age-related muscle atrophy in a senescence-accelerated mouse model and explored the underlying mechanisms. Twenty-six-week-old male, senescence-accelerated mouse resistant (SAMR) mice received the AIN-93G basal diet, while twenty-six-week-old male, senescence-accelerated mouse prone 8 (SAMP8) mice received the AIN-93G basal diet or a 2% TE powder-supplemented diet for ten weeks. Our findings revealed that TE supplementation showed certain effects on ameliorating the decrease in body weight, tibialis anterior weight, and mesenteric fat tissue weight in SAMP8 mice. TE improved gene expression in the glucocorticoid receptor-FoxO signaling pathway in skeletal muscle, including redd1, klf15, foxo1, murf1, and mafbx. Furthermore, TE might have the certain potential on improving the dynamic balance between anabolic and catabolic processes by inhibiting the binding of glucocorticoid receptor or FoxO1 to the glucocorticoid response element or FoxO-binding element in the MuRF1 promoter in skeletal muscle, thereby promoting muscle mass and strength, and preventing muscle atrophy and sarcopenia prevention. Moreover, TE may have reduced mitochondrial damage and maintained cell growth and division by downregulating the mRNA expression of the genes mfn2 and tsc2. Thus, the results indicated TE’s potential for preventing age-related muscle atrophy and sarcopenia.
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Affiliation(s)
- Weida Lyu
- Health Nutrition, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0032, Japan
- Department of Geriatric Medicine, Graduate School of Medicine, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Marika Kousaka
- Health Nutrition, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Huijuan Jia
- Health Nutrition, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Hisanori Kato
- Health Nutrition, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0032, Japan
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Lee CJ, Nicoll JX. Time Course Evaluation of Mitogen-Activated Protein Kinase Phosphorylation to Resistance Exercise: A Systematic Review. J Strength Cond Res 2023; 37:710-725. [PMID: 36727997 DOI: 10.1519/jsc.0000000000004409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
ABSTRACT Lee, CJ and Nicoll, JX. Time course evaluation of mitogen-activated protein kinase phosphorylation to resistance exercise: a systematic review. J Strength Cond Res 37(3): 710-725, 2023-Resistance exercise (RE) can increase the signaling activities of mitogen-activated protein kinases (MAPKs), specifically extracellular signal-regulated kinases 1/2 (ERK1/2), p90 ribosomal S6 kinases (p90RSK), c-Jun NH2-terminal kinases (JNK), and p38-MAPK. These RE-induced responses contribute to various intracellular processes modulating growth and development in skeletal muscles, playing an essential role in resistance training adaptations. The time course of MAPK phosphorylation to different RE conditions, such as training experience and varying loads, remains ambiguous. A systematic review was conducted to determine the effects of different post-RE recovery time points on the MAPK signaling cascade. In addition, the effects of loading and training statuses on MAPK responses were also investigated. The review was performed according to the preferred reporting items for systematic reviews and meta-analyses guidelines with a literature search incorporating 3 electronic databases. A modified version of the Downs and Black checklist was used to evaluate the methodological quality of the studies. The signaling responses were measured within a time range between immediately post-RE and >6 hours post-RE. Forty-four studies met the inclusion criteria, and all were classified as good-to-moderate methodological quality. Mitogen-activated protein kinase phosphorylation increased to different levels after RE, with the highest near the cessation of exercise. Although overall signaling was attenuated among trained individuals likely because of training adaptations, greater MAPK responses can be attributed to moderate loads of 65-85% 1RM regardless of the training experience. However, specific training-induced responses remain equivocal, and further investigations are required to determine the ideal training parameters to optimize anabolic intramuscular signaling, which may likely optimize resistance training adaptations.
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Affiliation(s)
- Christopher J Lee
- Department of Kinesiology, California State University, Northridge, Northridge, California
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Mechanotransduction for Muscle Protein Synthesis via Mechanically Activated Ion Channels. Life (Basel) 2023; 13:life13020341. [PMID: 36836698 PMCID: PMC9962945 DOI: 10.3390/life13020341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 01/24/2023] [Accepted: 01/26/2023] [Indexed: 02/03/2023] Open
Abstract
Cell mechanotransduction, the ability to detect physical forces and convert them into a series of biochemical events, is important for a wide range of physiological processes. Cells express an array of mechanosensors transducing physical forces into intracellular signaling cascades, including ion channels. Ion channels that can be directly activated by mechanical cues are known as mechanically activated (MA), or stretch-activated (SA), channels. In response to repeated exposures to mechanical stimulation in the form of resistance training, enhanced protein synthesis and fiber hypertrophy are elicited in skeletal muscle, whereas a lack of mechanical stimuli due to inactivity/mechanical unloading leads to reduced muscle protein synthesis and fiber atrophy. To date, the role of MA channels in the transduction of mechanical load to intracellular signaling pathways regulating muscle protein synthesis is poorly described. This review article will discuss MA channels in striated muscle, their regulation, and putative roles in the anabolic processes in muscle cells/fibers in response to mechanical stimuli.
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Understanding the Polyamine and mTOR Pathway Interaction in Breast Cancer Cell Growth. MEDICAL SCIENCES (BASEL, SWITZERLAND) 2022; 10:medsci10030051. [PMID: 36135836 PMCID: PMC9504347 DOI: 10.3390/medsci10030051] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 08/01/2022] [Accepted: 08/30/2022] [Indexed: 11/17/2022]
Abstract
The polyamines putrescine, spermidine and spermine are nutrient-like polycationic molecules involved in metabolic processes and signaling pathways linked to cell growth and cancer. One important pathway is the PI3K/Akt pathway where studies have shown that polyamines mediate downstream growth effects. Downstream of PI3K/Akt is the mTOR signaling pathway, a nutrient-sensing pathway that regulate translation initiation through 4EBP1 and p70S6K phosphorylation and, along with the PI3K/Akt, is frequently dysregulated in breast cancer. In this study, we investigated the effect of intracellular polyamine modulation on mTORC1 downstream protein and general translation state in two breast cancer cell lines, MCF-7 and MDA-MB-231. The effect of mTORC1 pathway inhibition on the growth and intracellular polyamines was also measured. Results showed that polyamine modulation alters 4EBP1 and p70S6K phosphorylation and translation initiation in the breast cancer cells. mTOR siRNA gene knockdown also inhibited cell growth and decreased putrescine and spermidine content. Co-treatment of inhibitors of polyamine biosynthesis and mTORC1 pathway induced greater cytotoxicity and translation inhibition in the breast cancer cells. Taken together, these data suggest that polyamines promote cell growth in part through interaction with mTOR pathway. Similarly intracellular polyamine content appears to be linked to mTOR pathway regulation. Finally, dual inhibition of polyamine and mTOR pathways may provide therapeutic benefits in some breast cancers.
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Jacko D, Schaaf K, Masur L, Windoffer H, Aussieker T, Schiffer T, Zacher J, Bloch W, Gehlert S. Repeated and Interrupted Resistance Exercise Induces the Desensitization and Re-Sensitization of mTOR-Related Signaling in Human Skeletal Muscle Fibers. Int J Mol Sci 2022; 23:ijms23105431. [PMID: 35628242 PMCID: PMC9141560 DOI: 10.3390/ijms23105431] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 05/07/2022] [Accepted: 05/09/2022] [Indexed: 02/06/2023] Open
Abstract
The acute resistance exercise (RE)-induced phosphorylation of mTOR-related signaling proteins in skeletal muscle can be blunted after repeated RE. The time frame in which the phosphorylation (p) of mTORS2448, p70S6kT421/S424, and rpS6S235/236 will be reduced during an RE training period in humans and whether progressive (PR) loading can counteract such a decline has not been described. (1) To enclose the time frame in which pmTORS2448, prpS6S235/236, and pp70S6kT421/S424 are acutely reduced after RE occurs during repeated RE. (2) To test whether PR will prevent that reduction compared to constant loading (CO) and (3) whether 10 days without RE may re-increase blunted signaling. Fourteen healthy males (24 ± 2.8 yrs.; 1.83 ± 0.1 cm; 79.3 ± 8.5 kg) were subjected to RE with either PR (n = 8) or CO (n = 6) loading. Subjects performed RE thrice per week, conducting three sets with 10−12 repetitions on a leg press and leg extension machine. Muscle biopsies were collected at rest (T0), 45 min after the first (T1), seventh (T7), 13th (T13), and 14th (X-T14) RE session. No differences were found between PR and CO for any parameter. Thus, the groups were combined, and the results show the merged values. prpS6S235/236 and pp70s6kT421/S424 were increased at T1, but were already reduced at T7 and up to T13 compared to T1. Ten days without RE re-increased prpS6S235/236 and pp70S6kT421/S424 at X-T14 to a level comparable to that of T1. pmTORS2448 was increased from T1 to X-T14 and did not decline over the training period. Single-fiber immunohistochemistry revealed a reduction in prpS6S235/236 in type I fibers from T1 to T13 and a re-increase at X-T14, which was more augmented in type II fibers at T13 (p < 0.05). The entity of myofibers revealed a high heterogeneity in the level of prpS6S235/236, possibly reflecting individual contraction-induced stress during RE. The type I and II myofiber diameter increased from T0 and T1 to T13 and X-T14 (p < 0.05) prpS6S235/236 and pp70s6kT421/S424 reflect RE-induced states of desensitization and re-sensitization in dependency on frequent loading by RE, but also by its cessation.
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Affiliation(s)
- Daniel Jacko
- Department of Molecular and Cellular Sports Medicine, Institute of Cardiovascular Research and Sports Medicine, German Sport University Cologne, 50933 Cologne, Germany; (D.J.); (K.S.); (L.M.); (H.W.); (T.A.); (W.B.)
- Olympic Base Center NRW/Rhineland, 50933 Cologne, Germany
| | - Kirill Schaaf
- Department of Molecular and Cellular Sports Medicine, Institute of Cardiovascular Research and Sports Medicine, German Sport University Cologne, 50933 Cologne, Germany; (D.J.); (K.S.); (L.M.); (H.W.); (T.A.); (W.B.)
| | - Lukas Masur
- Department of Molecular and Cellular Sports Medicine, Institute of Cardiovascular Research and Sports Medicine, German Sport University Cologne, 50933 Cologne, Germany; (D.J.); (K.S.); (L.M.); (H.W.); (T.A.); (W.B.)
| | - Hannes Windoffer
- Department of Molecular and Cellular Sports Medicine, Institute of Cardiovascular Research and Sports Medicine, German Sport University Cologne, 50933 Cologne, Germany; (D.J.); (K.S.); (L.M.); (H.W.); (T.A.); (W.B.)
| | - Thorben Aussieker
- Department of Molecular and Cellular Sports Medicine, Institute of Cardiovascular Research and Sports Medicine, German Sport University Cologne, 50933 Cologne, Germany; (D.J.); (K.S.); (L.M.); (H.W.); (T.A.); (W.B.)
| | - Thorsten Schiffer
- Outpatient Clinic for Sports Traumatology and Public Health Consultation, German Sport University Cologne, 50933 Cologne, Germany;
| | - Jonas Zacher
- Department ofPreventative and Rehabilitative Sports and Performance Medicine, Institute of Cardiology and Sports Medicine, German Sports University Cologne, 50933 Cologne, Germany;
| | - Wilhelm Bloch
- Department of Molecular and Cellular Sports Medicine, Institute of Cardiovascular Research and Sports Medicine, German Sport University Cologne, 50933 Cologne, Germany; (D.J.); (K.S.); (L.M.); (H.W.); (T.A.); (W.B.)
- German Research Centre of Elite Sport (Momentum), German Sport University Cologne, 50933 Cologne, Germany
| | - Sebastian Gehlert
- Department of Molecular and Cellular Sports Medicine, Institute of Cardiovascular Research and Sports Medicine, German Sport University Cologne, 50933 Cologne, Germany; (D.J.); (K.S.); (L.M.); (H.W.); (T.A.); (W.B.)
- Institute of Sport Science, Biosciences of Sports, University of Hildesheim, 31141 Hildesheim, Germany
- Correspondence: ; Tel.: +49-(0)-5121-883-580; Fax: +49-(0)-5121-883-591
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11
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Attwaters M, Hughes SM. Cellular and molecular pathways controlling muscle size in response to exercise. FEBS J 2022; 289:1428-1456. [PMID: 33755332 DOI: 10.1111/febs.15820] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 02/27/2021] [Accepted: 03/12/2021] [Indexed: 12/14/2022]
Abstract
From the discovery of ATP and motor proteins to synaptic neurotransmitters and growth factor control of cell differentiation, skeletal muscle has provided an extreme model system in which to understand aspects of tissue function. Muscle is one of the few tissues that can undergo both increase and decrease in size during everyday life. Muscle size depends on its contractile activity, but the precise cellular and molecular pathway(s) by which the activity stimulus influences muscle size and strength remain unclear. Four correlates of muscle contraction could, in theory, regulate muscle growth: nerve-derived signals, cytoplasmic calcium dynamics, the rate of ATP consumption and physical force. Here, we summarise the evidence for and against each stimulus and what is known or remains unclear concerning their molecular signal transduction pathways and cellular effects. Skeletal muscle can grow in three ways, by generation of new syncytial fibres, addition of nuclei from muscle stem cells to existing fibres or increase in cytoplasmic volume/nucleus. Evidence suggests the latter two processes contribute to exercise-induced growth. Fibre growth requires increase in sarcolemmal surface area and cytoplasmic volume at different rates. It has long been known that high-force exercise is a particularly effective growth stimulus, but how this stimulus is sensed and drives coordinated growth that is appropriately scaled across organelles remains a mystery.
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Affiliation(s)
- Michael Attwaters
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, King's College London, UK
| | - Simon M Hughes
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, King's College London, UK
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12
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Hodson N, Mazzulla M, Holowaty MNH, Kumbhare D, Moore DR. RPS6 phosphorylation occurs to a greater extent in the periphery of human skeletal muscle fibers, near focal adhesions, after anabolic stimuli. Am J Physiol Cell Physiol 2021; 322:C94-C110. [PMID: 34852208 DOI: 10.1152/ajpcell.00357.2021] [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]
Abstract
Following anabolic stimuli (mechanical loading and/or amino acid provision) the mechanistic target of rapamycin complex 1 (mTORC1), a master regulator of protein synthesis, translocates toward the cell periphery. However, it is unknown if mTORC1-mediated phosphorylation events occur in these peripheral regions or prior to translocation (i.e. in central regions). We therefore aimed to determine the cellular location of a mTORC1-mediated phosphorylation event, RPS6Ser240/244, in human skeletal muscle following anabolic stimuli. Fourteen young, healthy males either ingested a protein-carbohydrate beverage (0.25g/kg protein, 0.75g/kg carbohydrate) alone (n=7;23±5yrs;76.8±3.6kg;13.6±3.8%BF, FED) or following a whole-body resistance exercise bout (n=7;22±2yrs;78.1±3.6kg;12.2±4.9%BF, EXFED). Vastus lateralis muscle biopsies were obtained at rest (PRE) and 120 and 300min following anabolic stimuli. RPS6Ser240/244 phosphorylation measured by immunofluorescent staining or immunoblot was positively correlated (r=0.76, p<0.001). Peripheral staining intensity of p-RPS6Ser240/244 increased above PRE in both FED and EXFED at 120min (~54% and ~138% respectively, p<0.05) but was greater in EXFED at both post-stimuli time points (p<0.05). The peripheral-central ratio of p-RPS6240/244 staining displayed a similar pattern, even when corrected for total RPS6 distribution, suggesting RPS6 phosphorylation occurs to a greater extent in the periphery of fibers. Moreover, p-RPS6Ser240/244 intensity within paxillin-positive regions, a marker of focal adhesion complexes, was elevated at 120min irrespective of stimulus (p=0.006) before returning to PRE at 300min. These data confirm that RPS6Ser240/244 phosphorylation occurs in the region of human muscle fibers to which mTOR translocates following anabolic stimuli and identifies focal adhesion complexes as a potential site of mTORC1 regulation in vivo.
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Affiliation(s)
- Nathan Hodson
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, ON, Canada
| | - Michael Mazzulla
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, ON, Canada
| | - Maksym N H Holowaty
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, ON, Canada
| | | | - Daniel R Moore
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, ON, Canada
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13
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Francis EC, Dabelea D, Boyle KE, Jansson T, Perng W. Maternal Diet Quality Is Associated with Placental Proteins in the Placental Insulin/Growth Factor, Environmental Stress, Inflammation, and mTOR Signaling Pathways: The Healthy Start ECHO Cohort. J Nutr 2021; 152:816-825. [PMID: 34850052 PMCID: PMC8891174 DOI: 10.1093/jn/nxab403] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 10/19/2021] [Accepted: 11/23/2021] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Maternal nutritional status affects placental function, which may underlie the intrauterine origins of obesity and diabetes. The extent to which diet quality is associated with placental signaling and which specific pathways are impacted is unknown. OBJECTIVES To examine sex-specific associations of maternal diet quality according to the Healthy Eating Index (HEI)-developed to align with recommendations from the Dietary Guidelines for Americans-with placental proteins involved in metabolism and mediators of environmental stress, inflammation, and growth factors. METHODS Among 108 women from the Healthy Start cohort with a mean ± SD age of 29.0 ± 6.1 y and a prepregnancy BMI (in kg/m2) of 24.8 ± 5.3, we conducted multivariable linear regression analysis stratified by offspring sex. We adjusted for maternal race or ethnicity, age, education, prenatal smoking habits, and physical activity and tested for an association of maternal HEI >57 compared with ≤57 and the abundance and phosphorylation of key proteins involved in insulin/growth factor signaling; mediators of environmental stress, inflammation, and growth factors; mechanistic target of rapamycin signaling proteins; and energy sensing in placental villus samples. HEI >57 was chosen given its prior relevance among Healthy Start mother-child dyads. RESULTS In adjusted models, HEI >57 was associated with greater abundance of insulin receptor β (0.80; 95% CI: 0.11, 1.49) in placentas of females. In males, maternal HEI >57 was associated with greater activation and abundance of select placental nutrient-sensing proteins and environmental stress, inflammation, and growth factor proteins (S6K1Thr389/S6K1: 0.81; 95% CI: 0.21, 1.41; JNK1Thr183/Tyr185/JNK1: 0.82; 95% CI: 0.27, 1.37; JNK2Thr183/Tyr185/JNK2: 0.57; 95% CI: 0.02, 1.11). CONCLUSIONS Higher-quality diet had sex-specific associations with placental protein abundance/phosphorylation. Given that these proteins have been correlated with neonatal anthropometry, our findings provide insight into modifiable factors and placental pathways that should be examined in future studies as potential links between maternal diet and offspring metabolic health. This trial was registered at clinicaltrials.gov as NCT02273297.
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Affiliation(s)
| | - Dana Dabelea
- The Lifecourse Epidemiology of Adiposity and Diabetes (LEAD) Center, Aurora, CO, USA,Department of Epidemiology, Colorado School of Public Health, University of Colorado Denver Anschutz Medical Campus, Aurora, CO, USA,Department of Pediatrics, School of Medicine, University of Colorado Denver Anschutz Medical Campus, Aurora, CO, USA
| | - Kristen E Boyle
- The Lifecourse Epidemiology of Adiposity and Diabetes (LEAD) Center, Aurora, CO, USA,Section of Nutrition, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Thomas Jansson
- Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Wei Perng
- The Lifecourse Epidemiology of Adiposity and Diabetes (LEAD) Center, Aurora, CO, USA,Section of Nutrition, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA,Deptartment of Nutritional Sciences, University of Michigan School of Public Health, Ann Arbor, MI, USA
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14
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Yazid MD, Hung-Chih C. Perturbation of PI3K/Akt signaling affected autophagy modulation in dystrophin-deficient myoblasts. Cell Commun Signal 2021; 19:105. [PMID: 34706731 PMCID: PMC8554905 DOI: 10.1186/s12964-021-00785-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 09/06/2021] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND The absence of dystrophin has gave a massive impact on myotube development in Muscular Dystrophy pathogenesis. One of the conserved signaling pathways involved in skeletal muscle differentiation is the PI3K/Akt/mTOR pathway that plays a vital role in autophagy regulation. To further understand and establish targeted therapy in dystrophin-deficient myoblasts, protein expression profiling has been determined which provides information on perturbed autophagy modulation and activation. METHODS In this study, a dystrophin-deficient myoblast cell line established from the skeletal muscle of a dystrophic (mdx) mouse was used as a model. The dfd13 (dystrophin-deficient) and C2C12 (non-dystrophic) myoblasts were cultured in low mitogen conditions for 10 days to induce differentiation. The cells were subjected to total protein extraction prior to Western blotting assay technique. Protein sub-fractionation has been conducted to determine protein localization. The live-cell analysis of autophagy assay was done using a flow cytometer. RESULTS In our culture system, the dfd13 myoblasts did not achieve terminal differentiation. PTEN expression was profoundly increased in dfd13 myoblasts throughout the differentiation day subsequently indicates perturbation of PI3K/Akt/mTOR regulation. In addition, rictor-mTORC2 was also found inactivated in this event. This occurrence has caused FoxO3 misregulation leads to higher activation of autophagy-related genes in dfd13 myoblasts. Autophagosome formation was increased as LC3B-I/II showed accumulation upon differentiation. However, the ratio of LC3B lipidation and autophagic flux were shown decreased which exhibited dystrophic features. CONCLUSION Perturbation of the PTEN-PI3K/Akt pathway triggers excessive autophagosome formation and subsequently reduced autophagic flux within dystrophin-deficient myoblasts where these findings are of importance to understand Duchenne Muscular Dystrophy (DMD) patients. We believe that some manipulation within its regulatory signaling reported in this study could help restore muscle homeostasis and attenuate disease progression. Video Abstract.
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Affiliation(s)
- Muhammad Dain Yazid
- Centre for Tissue Engineering and Regenerative Medicine, Faculty of Medicine, UKM Medical Centre, Jalan Yaacob Latiff, 56000 Cheras, Kuala Lumpur, Malaysia
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT UK
| | - Chen Hung-Chih
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT UK
- Academia Sinica, No. 28, Lane 70, Section 2, Yanjiuyuan Rd, Nangang District, Taipei City, 115 Taiwan
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15
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Cirone M. Cancer cells dysregulate PI3K/AKT/mTOR pathway activation to ensure their survival and proliferation: mimicking them is a smart strategy of gammaherpesviruses. Crit Rev Biochem Mol Biol 2021; 56:500-509. [PMID: 34130564 DOI: 10.1080/10409238.2021.1934811] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The serine/threonine kinase mammalian target of rapamycin (mTOR) is the catalytic subunit of two complexes, mTORC1 and mTORC2, which have common and distinct subunits that mediate separate and overlapping functions. mTORC1 is activated by plenty of nutrients, and the two complexes can be activated by PI3K signaling. mTORC2 acts as an upstream regulator of AKT, and mTORC1 acts as a downstream effector. mTOR signaling integrates both intracellular and extracellular signals, acting as a key regulator of cellular metabolism, growth, and survival. A dysregulated activation of mTOR, as result of PI3K pathway or mTOR regulatory protein mutations or even due to the presence of cellular or viral oncogenes, is a common finding in cancer and represents a central mechanism in cancerogenesis. In the final part of this review, we will focus on the PI3K/AKT/mTOR activation by the human gammaherpesviruses EBV and KSHV that hijack this pathway to promote their-mediated oncogenic transformation and pathologies.
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Affiliation(s)
- Mara Cirone
- Department of Experimental Medicine, "Sapienza" University of Rome, Rome, Italy.,Laboratory affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Rome, Italy
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16
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Navas-Pérez E, Vicente-García C, Mirra S, Burguera D, Fernàndez-Castillo N, Ferrán JL, López-Mayorga M, Alaiz-Noya M, Suárez-Pereira I, Antón-Galindo E, Ulloa F, Herrera-Úbeda C, Cuscó P, Falcón-Moya R, Rodríguez-Moreno A, D'Aniello S, Cormand B, Marfany G, Soriano E, Carrión ÁM, Carvajal JJ, Garcia-Fernàndez J. Characterization of an eutherian gene cluster generated after transposon domestication identifies Bex3 as relevant for advanced neurological functions. Genome Biol 2020; 21:267. [PMID: 33100228 PMCID: PMC7586669 DOI: 10.1186/s13059-020-02172-3] [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: 04/25/2020] [Accepted: 09/25/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND One of the most unusual sources of phylogenetically restricted genes is the molecular domestication of transposable elements into a host genome as functional genes. Although these kinds of events are sometimes at the core of key macroevolutionary changes, their origin and organismal function are generally poorly understood. RESULTS Here, we identify several previously unreported transposable element domestication events in the human and mouse genomes. Among them, we find a remarkable molecular domestication that gave rise to a multigenic family in placental mammals, the Bex/Tceal gene cluster. These genes, which act as hub proteins within diverse signaling pathways, have been associated with neurological features of human patients carrying genomic microdeletions in chromosome X. The Bex/Tceal genes display neural-enriched patterns and are differentially expressed in human neurological disorders, such as autism and schizophrenia. Two different murine alleles of the cluster member Bex3 display morphological and physiopathological brain modifications, such as reduced interneuron number and hippocampal electrophysiological imbalance, alterations that translate into distinct behavioral phenotypes. CONCLUSIONS We provide an in-depth understanding of the emergence of a gene cluster that originated by transposon domestication and gene duplication at the origin of placental mammals, an evolutionary process that transformed a non-functional transposon sequence into novel components of the eutherian genome. These genes were integrated into existing signaling pathways involved in the development, maintenance, and function of the CNS in eutherians. At least one of its members, Bex3, is relevant for higher brain functions in placental mammals and may be involved in human neurological disorders.
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Affiliation(s)
- Enrique Navas-Pérez
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, and Institut de Biomedicina (IBUB), University of Barcelona, 08028, Barcelona, Spain
| | - Cristina Vicente-García
- Centro Andaluz de Biología del Desarrollo, CSIC-UPO-JA, Universidad Pablo de Olavide, 41013, Sevilla, Spain
| | - Serena Mirra
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, and Institut de Biomedicina (IBUB), University of Barcelona, 08028, Barcelona, Spain.,Department of Cell Biology, Physiology and Immunology, and Institute of Neurosciences, University of Barcelona, 08028, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III (ISCIII), Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III (ISCIII), 28029, Madrid, Spain
| | - Demian Burguera
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, and Institut de Biomedicina (IBUB), University of Barcelona, 08028, Barcelona, Spain.,Department of Zoology, Charles University, Vinicna 7, 12844, Prague, Czech Republic
| | - Noèlia Fernàndez-Castillo
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, and Institut de Biomedicina (IBUB), University of Barcelona, 08028, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III (ISCIII), Madrid, Spain.,Institut de Recerca Sant Joan de Déu (IR-SJD), Esplugues de Llobregat, 08950, Barcelona, Spain
| | - José Luis Ferrán
- Department of Human Anatomy, School of Medicine, University of Murcia and IMIB-Arrixaca Institute, 30120, Murcia, Spain
| | - Macarena López-Mayorga
- Centro Andaluz de Biología del Desarrollo, CSIC-UPO-JA, Universidad Pablo de Olavide, 41013, Sevilla, Spain
| | - Marta Alaiz-Noya
- Department of Physiology, Anatomy and Cell Biology, Universidad Pablo de Olavide, 41013, Sevilla, Spain.,Present Address: Instituto de Neurociencias de Alicante (Universidad Miguel Hernández - Consejo Superior de Investigaciones Científicas), Alicante, Spain
| | - Irene Suárez-Pereira
- Department of Physiology, Anatomy and Cell Biology, Universidad Pablo de Olavide, 41013, Sevilla, Spain.,Present Address: Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Neuropsychopharmacology and psychobiology research group, UCA, INiBICA, Cádiz, Spain
| | - Ester Antón-Galindo
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, and Institut de Biomedicina (IBUB), University of Barcelona, 08028, Barcelona, Spain
| | - Fausto Ulloa
- Department of Cell Biology, Physiology and Immunology, and Institute of Neurosciences, University of Barcelona, 08028, Barcelona, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III (ISCIII), 28029, Madrid, Spain
| | - Carlos Herrera-Úbeda
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, and Institut de Biomedicina (IBUB), University of Barcelona, 08028, Barcelona, Spain
| | - Pol Cuscó
- Genome Architecture, Gene Regulation, Stem Cells and Cancer Programme, Centre for Genomic Regulation (CRG), the Barcelona Institute of Science and Technology, 08003, Barcelona, Spain.,Universitat Pompeu Fabra (UPF), 08003, Barcelona, Spain
| | - Rafael Falcón-Moya
- Department of Physiology, Anatomy and Cell Biology, Universidad Pablo de Olavide, 41013, Sevilla, Spain
| | - Antonio Rodríguez-Moreno
- Department of Physiology, Anatomy and Cell Biology, Universidad Pablo de Olavide, 41013, Sevilla, Spain
| | - Salvatore D'Aniello
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, 80121, Naples, Italy
| | - Bru Cormand
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, and Institut de Biomedicina (IBUB), University of Barcelona, 08028, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III (ISCIII), Madrid, Spain.,Institut de Recerca Sant Joan de Déu (IR-SJD), Esplugues de Llobregat, 08950, Barcelona, Spain
| | - Gemma Marfany
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, and Institut de Biomedicina (IBUB), University of Barcelona, 08028, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III (ISCIII), Madrid, Spain.,Institut de Recerca Sant Joan de Déu (IR-SJD), Esplugues de Llobregat, 08950, Barcelona, Spain
| | - Eduardo Soriano
- Department of Cell Biology, Physiology and Immunology, and Institute of Neurosciences, University of Barcelona, 08028, Barcelona, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III (ISCIII), 28029, Madrid, Spain.,Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010, Barcelona, Spain
| | - Ángel M Carrión
- Department of Physiology, Anatomy and Cell Biology, Universidad Pablo de Olavide, 41013, Sevilla, Spain
| | - Jaime J Carvajal
- Centro Andaluz de Biología del Desarrollo, CSIC-UPO-JA, Universidad Pablo de Olavide, 41013, Sevilla, Spain.
| | - Jordi Garcia-Fernàndez
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, and Institut de Biomedicina (IBUB), University of Barcelona, 08028, Barcelona, Spain.
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17
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MacDonald TL, Pattamaprapanont P, Pathak P, Fernandez N, Freitas EC, Hafida S, Mitri J, Britton SL, Koch LG, Lessard SJ. Hyperglycaemia is associated with impaired muscle signalling and aerobic adaptation to exercise. Nat Metab 2020; 2:902-917. [PMID: 32694831 PMCID: PMC8278496 DOI: 10.1038/s42255-020-0240-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 06/12/2020] [Indexed: 12/11/2022]
Abstract
Increased aerobic exercise capacity, as a result of exercise training, has important health benefits. However, some individuals are resistant to improvements in exercise capacity, probably due to undetermined genetic and environmental factors. Here, we show that exercise-induced improvements in aerobic capacity are blunted and aerobic remodelling of skeletal muscle is impaired in several animal models associated with chronic hyperglycaemia. Our data point to chronic hyperglycaemia as a potential negative regulator of aerobic adaptation, in part, via glucose-mediated modifications of the extracellular matrix, impaired vascularization and aberrant mechanical signalling in muscle. We also observe low exercise capacity and enhanced c-Jun N-terminal kinase activation in response to exercise in humans with impaired glucose tolerance. Our work indicates that current shifts in dietary and metabolic health, associated with increasing incidence of hyperglycaemia, might impair muscular and organismal adaptations to exercise training, including aerobic capacity as one of its key health outcomes.
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Affiliation(s)
- Tara L MacDonald
- Research Division, Joslin Diabetes Center, Boston, MA, USA
- Harvard Medical School, Harvard University, Boston, MA, USA
- Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA
| | - Pattarawan Pattamaprapanont
- Research Division, Joslin Diabetes Center, Boston, MA, USA
- Harvard Medical School, Harvard University, Boston, MA, USA
- Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA
| | - Prerana Pathak
- Research Division, Joslin Diabetes Center, Boston, MA, USA
| | | | - Ellen C Freitas
- School of Physical Education and Sport, University of São Paulo, Ribeirão Preto, Brazil
| | - Samar Hafida
- Research Division, Joslin Diabetes Center, Boston, MA, USA
- Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA
| | - Joanna Mitri
- Research Division, Joslin Diabetes Center, Boston, MA, USA
- Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA
| | - Steven L Britton
- Department of Molecular and Integrative Physiology, and Department of Anesthesiology, University of Michigan, Ann Arbor, MI, USA
| | - Lauren G Koch
- Department of Physiology and Pharmacology, The University of Toledo, Toledo, OH, USA
| | - Sarah J Lessard
- Research Division, Joslin Diabetes Center, Boston, MA, USA.
- Harvard Medical School, Harvard University, Boston, MA, USA.
- Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA.
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18
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Figueiredo VC, Dungan CM, Peterson CA, McCarthy JJ. On the appropriateness of antibody selection to estimate mTORC1 activity. Acta Physiol (Oxf) 2020; 228:e13354. [PMID: 31365789 DOI: 10.1111/apha.13354] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Vandre C. Figueiredo
- Department of Rehabilitation Sciences, College of Health Sciences University of Kentucky Lexington Kentucky
- The Center for Muscle Biology University of Kentucky Lexington Kentucky
| | - Cory M. Dungan
- Department of Rehabilitation Sciences, College of Health Sciences University of Kentucky Lexington Kentucky
- The 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
- The Center for Muscle Biology University of Kentucky Lexington Kentucky
| | - John J. McCarthy
- The Center for Muscle Biology University of Kentucky Lexington Kentucky
- Department of Physiology, College of Medicine University of Kentucky Lexington Kentucky
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19
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D'Hulst G, Soro-Arnaiz I, Masschelein E, Veys K, Fitzgerald G, Smeuninx B, Kim S, Deldicque L, Blaauw B, Carmeliet P, Breen L, Koivunen P, Zhao SM, De Bock K. PHD1 controls muscle mTORC1 in a hydroxylation-independent manner by stabilizing leucyl tRNA synthetase. Nat Commun 2020; 11:174. [PMID: 31924757 PMCID: PMC6954236 DOI: 10.1038/s41467-019-13889-6] [Citation(s) in RCA: 266] [Impact Index Per Article: 66.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 12/06/2019] [Indexed: 02/08/2023] Open
Abstract
mTORC1 is an important regulator of muscle mass but how it is modulated by oxygen and nutrients is not completely understood. We show that loss of the prolyl hydroxylase domain isoform 1 oxygen sensor in mice (PHD1KO) reduces muscle mass. PHD1KO muscles show impaired mTORC1 activation in response to leucine whereas mTORC1 activation by growth factors or eccentric contractions was preserved. The ability of PHD1 to promote mTORC1 activity is independent of its hydroxylation activity but is caused by decreased protein content of the leucyl tRNA synthetase (LRS) leucine sensor. Mechanistically, PHD1 interacts with and stabilizes LRS. This interaction is promoted during oxygen and amino acid depletion and protects LRS from degradation. Finally, elderly subjects have lower PHD1 levels and LRS activity in muscle from aged versus young human subjects. In conclusion, PHD1 ensures an optimal mTORC1 response to leucine after episodes of metabolic scarcity. mTORC1 is an important regulator of muscle mass. Here, the authors show that the PHD1 controls muscle mass in a hydroxylation-independent manner. PHD1 prevents the degradation of leucine sensor LRS during oxygen and amino acid depletion to ensure effective mTORC1 activation in response to leucine.
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Affiliation(s)
- Gommaar D'Hulst
- Department Health Sciences and Technology, Laboratory of Exercise and Health, Swiss Federal Institute of Technology (ETH) Zurich, Zurich, Switzerland
| | - Inés Soro-Arnaiz
- Department Health Sciences and Technology, Laboratory of Exercise and Health, Swiss Federal Institute of Technology (ETH) Zurich, Zurich, Switzerland
| | - Evi Masschelein
- Department Health Sciences and Technology, Laboratory of Exercise and Health, Swiss Federal Institute of Technology (ETH) Zurich, Zurich, Switzerland
| | - Koen Veys
- Laboratory of Angiogenesis and Vascular Metabolism, VIB Center for Cancer Biology (CCB), VIB, Leuven, Belgium.,Laboratory of Angiogenesis and Vascular Metabolism, Department of Oncology, KU Leuven, Leuven, Belgium
| | - Gillian Fitzgerald
- Department Health Sciences and Technology, Laboratory of Exercise and Health, Swiss Federal Institute of Technology (ETH) Zurich, Zurich, Switzerland
| | - Benoit Smeuninx
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.,MRC Arthritis Research UK Centre for Musculoskeletal Ageing Research, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Sunghoon Kim
- Medicinal Bioconvergence Research Center, College of Pharmacy, Seoul National University, Gwanak-gu, Seoul, South Korea
| | - Louise Deldicque
- Institute of Neuroscience, Université catholique de Louvain, Louvain-La-Neuve, Belgium
| | - Bert Blaauw
- Department of Biomedical Sciences, Venetian Institute of Molecular Medicine, University of Padova, Padova, Italy
| | - Peter Carmeliet
- Laboratory of Angiogenesis and Vascular Metabolism, VIB Center for Cancer Biology (CCB), VIB, Leuven, Belgium.,Laboratory of Angiogenesis and Vascular Metabolism, Department of Oncology, KU Leuven, Leuven, Belgium
| | - Leigh Breen
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.,MRC Arthritis Research UK Centre for Musculoskeletal Ageing Research, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Peppi Koivunen
- Biocenter Oulu, Faculty of Biochemistry and Molecular Medicine, Oulu Center for Cell-Matrix Research, University of Oulu, Oulu, Finland
| | - Shi-Min Zhao
- Obstetrics and Gynaecology Hospital of Fudan University, State Key Lab of Genetic Engineering, School of Life Sciences and Institutes of Biomedical Sciences, Shanghai, P. R. China.,Institute of Biomedical Science, Fudan University, Shanghai, P. R. China.,Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu, P. R. China
| | - Katrien De Bock
- Department Health Sciences and Technology, Laboratory of Exercise and Health, Swiss Federal Institute of Technology (ETH) Zurich, Zurich, Switzerland.
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20
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Takegaki J, Sase K, Fujita S. Repeated bouts of resistance exercise attenuate mitogen-activated protein-kinase signal responses in rat skeletal muscle. Biochem Biophys Res Commun 2019; 520:73-78. [PMID: 31582215 DOI: 10.1016/j.bbrc.2019.09.050] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 09/12/2019] [Indexed: 11/24/2022]
Abstract
Resistance exercise training induces skeletal muscle hypertrophy, but repeated bouts gradually attenuate this anabolic effect. Attenuation of mechanistic target of rapamycin complex 1 (mTORC1) activation by repetitive resistance exercise is involved in this process, but the mechanism leading to inactivation of mTORC1 remains unclear. In this study, we investigated repetition-dependent changes in mitogen-activated protein kinases (MAPKs) and the 90-kDa ribosomal S6 kinase (p90RSK), upstream regulators of mTORC1, in a rat resistance-exercise model. Resistance exercise was associated with increased phosphorylation of 70-kDa ribosomal protein S6 kinase (Thr389), but its magnitude was decreased with repeated bouts. Additionally, phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 (Thr202/Tyr204) and p38 MAPK (Thr180/Tyr182), which are MAPKs, decreased with repeated bouts. A similar result was also observed for p90RSK phosphorylation (Thr573). These observations indicate that repeated bouts desensitized ERK1/2 and p38 MAPK, subsequently attenuating p90RSK phosphorylation. This reduction in p90RSK phosphorylation may have been partly responsible for the blunting of mTORC1 activation by resistance exercise.
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Affiliation(s)
- Junya Takegaki
- Ritsumeikan Global Innovation Research Organization, Ritsumeikan University, 1-1-1 Noji-higashi, Kusatsu, Shiga, 525-8577, Japan.
| | - Kohei Sase
- Ritsumeikan Global Innovation Research Organization, Ritsumeikan University, 1-1-1 Noji-higashi, Kusatsu, Shiga, 525-8577, Japan; Faculty of Sport and Health Science, Ritsumeikan University, 1-1-1 Noji-higashi, Kusatsu, Shiga, 525-8577, Japan.
| | - Satoshi Fujita
- Faculty of Sport and Health Science, Ritsumeikan University, 1-1-1 Noji-higashi, Kusatsu, Shiga, 525-8577, Japan.
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21
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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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22
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Ato S, Tsushima D, Isono Y, Suginohara T, Maruyama Y, Nakazato K, Ogasawara R. The Effect of Changing the Contraction Mode During Resistance Training on mTORC1 Signaling and Muscle Protein Synthesis. Front Physiol 2019; 10:406. [PMID: 31057416 PMCID: PMC6482468 DOI: 10.3389/fphys.2019.00406] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2018] [Accepted: 03/22/2019] [Indexed: 12/16/2022] Open
Abstract
Acute resistance exercise (RE) increases muscle protein synthesis (MPS) via activation of mechanistic target of rapamycin complex (mTORC), and chronic resistance exercise training (RT) results in skeletal muscle hypertrophy. Although MPS in response to RE is blunted over time during RT, no effective restorative strategy has been identified. Since eccentric muscle contraction (EC) has the potential to strongly stimulate mTORC1 activation and MPS, changing the muscle contraction mode to EC might maintain the MPS response to RE during chronic RT. Male rats were randomly divided into RE (1 bout of RE) and RT (13 bouts of RE) groups. Additionally, each group was subdivided into isometric contraction (IC) and EC subgroups. The RE groups performed acute, unilateral RE using IC or EC. The RT groups performed 12 bouts of unilateral RE using IC. For bout 13, the RT-IC subgroup performed a further IC bout, while the RT-EC subgroup changed to EC. All muscle contractions were induced by percutaneous electrical stimulation. Muscle samples were obtained at 6 h post exercise in all groups. After the 1st RE bout, the EC group showed significantly higher p70S6K Thr389 phosphorylation than the IC group. However, the phosphorylation of other mTORC1-associated proteins (4E-BP1 and ribosomal protein S6) and the MPS response did not differ between the contraction modes. After the 13th bout of RE, mTORC1 activation and the MPS response were significantly blunted as compared with the 1st bout of RE. Changing from IC to EC did not improve these responses. In conclusion, changing the contraction mode to EC does not reinvigorate the blunted mTORC1 activation and MPS in response to RE during chronic RT.
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Affiliation(s)
- Satoru Ato
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Nagoya, Japan
| | - Daisuke Tsushima
- Department of Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Yurie Isono
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Nagoya, Japan
| | - Takeshi Suginohara
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Nagoya, Japan
| | - Yuki Maruyama
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Nagoya, Japan
| | - Koichi Nakazato
- Department of Exercise Physiology, Nippon Sport Science University, Tokyo, Japan
| | - Riki Ogasawara
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Nagoya, Japan
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23
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Ferrié C, Kasper S, Wanivenhaus F, Flück M. Focal adhesion kinase coordinates costamere-related JNK signaling with muscle fiber transformation after Achilles tenotomy and tendon reconstruction. Exp Mol Pathol 2019; 108:42-56. [PMID: 30879953 DOI: 10.1016/j.yexmp.2019.03.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 01/29/2019] [Accepted: 03/12/2019] [Indexed: 01/24/2023]
Abstract
Achilles tendon rupture necessitates rapid tendon reattachment to reinstate plantar flexion before affected muscles deteriorate through muscle fiber atrophy and transformation. The implicated process may involve alterations in sarcolemmal sites of myofibril attachment (costameres), which control myofibrillogenesis via a mechano-regulated mechanism through integrin-associated focal adhesion kinase (FAK). We assessed the contribution of FAK to alterations in fiber type composition and expression of costamere-associated structural proteins, the phosphorylation status of Y397-FAK and downstream mTOR/JNK-P70S6K hypertrophy signaling in rat soleus muscle after Achilles tenotomy and tendon repair. Achilles tenotomy induced a profound deterioration of muscle composition 14 days, but not 4 days, following tendon release, comprising specifically increased area percentages of fast type fibers, fibers with internal nuclei, and connective tissue. Concomitantly, expression of costameric proteins FAK and meta-vinculin, and phosphorylation of T421/S424-P70S6K and T183/Y185-JNK was elevated, all of which was mitigated by tendon reattachment immediately after release. Overexpression of FAK in soleus muscle fibers and reattachment corrected the expression of meta- and gamma-vinculin isoforms to the lower levels in mock controls while further enhancing T183/Y185-JNK phosphorylation and levels of FAK C-terminus-related inhibitory proteins. Co-overexpression of the FAK inhibitor, FRNK, lowered FAK-overexpression driven Y397-FAK phosphorylation and T183/Y185-JNK phosphorylation. FAK levels correlated to molecular and cellular hallmarks of fiber degeneration. The findings demarcate the window between 4 and 14 days after tenotomy as costamere-dependent muscle transformation process, and expose that FAK overexpression prevents molecular aspects of the pathology which within the study limitations does not result in the mitigation of muscle fiber degeneration.250 words.
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Affiliation(s)
- Céline Ferrié
- Laboratory for Muscle Plasticity, Department of Orthopedics, University of Zurich, Balgrist Campus, Zurich, Switzerland
| | - Stephanie Kasper
- Laboratory for Muscle Plasticity, Department of Orthopedics, University of Zurich, Balgrist Campus, Zurich, Switzerland
| | - Florian Wanivenhaus
- Department of Orthopedic Surgery, Balgrist University Hospital, Zurich, Switzerland
| | - Martin Flück
- Laboratory for Muscle Plasticity, Department of Orthopedics, University of Zurich, Balgrist Campus, Zurich, Switzerland.
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24
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Wang Q, Shen B, Qin X, Liu S, Feng J. Akt/mTOR and AMPK signaling pathways are responsible for liver X receptor agonist GW3965-enhanced gefitinib sensitivity in non-small cell lung cancer cell lines. Transl Cancer Res 2019; 8:66-76. [PMID: 35116735 PMCID: PMC8797756 DOI: 10.21037/tcr.2018.12.34] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 12/14/2018] [Indexed: 12/25/2022]
Abstract
BACKGROUND This study was to systemically analyze the mechanism of LXR ligand GW3965-induced sensitivity to EGFR-TKI in EGFR-TKI-resistant non-small cell lung cancer (NSCLC) cell lines. METHODS Gefitinib-resistant PC9 cell line (EGFR exon 19 deletion) was treated with single and combined treatment with GW3965 and gefitinib. Cell viability, apoptosis and autophagy were detected using MTT, flow cytometric analysis and immunofluorescent analysis, respectively. Autophagy-related signaling pathways were detected using Western blot analysis. RESULTS Inhibited cell viability by single and combined treatment with gefitinib and GW3965 were observed. Combined treatment with gefitinib and GW3965 increased LC3 II/I ratio and Beclin 1 expression. Synergistic effect of gefitinib and GW3965 on apoptosis and autophagosome accumulation as well as on the inhibition of Akt/mTOR signaling and activation of AMP-activated protein kinase (AMPK) was observed in gefitinib-resistant PC9 cells. AMPK expression showed similar profile with apoptosis and autophagy of PC9 cells. CONCLUSIONS We confirmed that GW3965 and gefitinib showed synergistic effect on Akt/mTOR inhibition, apoptosis and autophagy of lung cancer cells. Gefitinib sensitivity in PC9 cell line might be mediated by Akt/mTOR, AMPK and JNK signaling pathways.
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Affiliation(s)
- Qingbo Wang
- The Fourth Clinical School of Nanjing Medical University, Nanjing 210029, China
| | - Bo Shen
- Department of Chemotherapy, Nanjing Medical University Affiliated Cancer Hospital Cancer Institute of Jiangsu Province, Nanjing 210009, China
| | - Xiaobing Qin
- The Fourth Clinical School of Nanjing Medical University, Nanjing 210029, China
| | - Siwen Liu
- Department of Chemotherapy, Nanjing Medical University Affiliated Cancer Hospital Cancer Institute of Jiangsu Province, Nanjing 210009, China
| | - Jifeng Feng
- Department of Chemotherapy, Nanjing Medical University Affiliated Cancer Hospital Cancer Institute of Jiangsu Province, Nanjing 210009, China
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25
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Olsen LA, Nicoll JX, Fry AC. The skeletal muscle fiber: a mechanically sensitive cell. Eur J Appl Physiol 2019; 119:333-349. [PMID: 30612167 DOI: 10.1007/s00421-018-04061-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 12/21/2018] [Indexed: 12/12/2022]
Abstract
The plasticity of skeletal muscle, whether an increase in size, change in metabolism, or alteration in structural properties, is in a continuous state of flux largely dependent upon physical activity. Much of the past research has expounded upon these ever-changing aspects of the muscle fiber following exercise. Specifically, endocrine and paracrine signaling have been heavily investigated lending to much of the past literature comprised of such endocrinological dynamics following muscle activity. Mechanotransduction, the ability of a cell to convert a mechanical stimulus into an intracellular biochemical response, has garnered much less attention. Recent work, however, has demonstrated the physical continuity of the muscle fiber, specifically demonstrating a continuous physical link between the extracellular matrix (ECM), cytoskeleton, and nuclear matrix as a means to rapidly regulate gene expression following a mechanical stimulus. Similarly, research has shown mechanical stimuli to directly influence cytoplasmic signaling whether through oxidative adaptations, increased muscle size, or enhanced muscle integrity. Regrettably, minimal research has investigated the role that exercise may play within the mechanotransducing signaling cascades. This proposed line of study may prove paramount as muscle-related diseases greatly impact one's ability to lead an independent lifestyle along with contributing a substantial burden upon the economy. Thus, this review explores both biophysical and biochemical mechanotransduction, and how these signaling pathways may be influenced following exercise.
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Affiliation(s)
- Luke A Olsen
- Biomedical Sciences, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Justin X Nicoll
- Department of Kinesiology, California State University, Northridge, CA, 91330-8287, USA
| | - Andrew C Fry
- Department of Health, Sport, and Exercise Sciences, University of Kansas, Lawrence, KS, 66045, USA.
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26
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Nicoll JX, Fry AC, Mosier EM. Sex-based differences in resting MAPK, androgen, and glucocorticoid receptor phosphorylation in human skeletal muscle. Steroids 2019; 141:23-29. [PMID: 30414425 DOI: 10.1016/j.steroids.2018.11.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 11/05/2018] [Indexed: 02/07/2023]
Abstract
PURPOSE To determine if there is differential expression and phosphorylation of the androgen receptor (AR), glucocorticoid receptor (GR), and mitogen-activated protein kinases (MAPK) in skeletal muscle at rest between males and females. METHODS Ten college-aged males (mean ± SD; age = 22 ± 2.4 yrs, ht = 175 ± 7 cm, body mass = 84.1 ± 11.8 kg) and ten females (mean ± SD; age = 20 ± 0.9 yrs; ht = 169 ± 7 cm; body mass = 67.1 ± 8.7 kg) reported to the laboratory following an overnight fast. Resting muscle biopsies were collected from the vastus lateralis and analyzed for total and phosphorylated GR (ser134, ser211, and ser226), total and phosphorylated AR (ser81, ser213, ser515, ser650), and total and phosphorylated MAPK (ERK, JNK, p38) via western blotting. A phosphorylation index (PI) was calculated to determine phosphorylated receptor expression after accounting for differences in total receptor content. RESULTS Males had more total AR compared to females (+42 ± 4%; p < 0.001). Females had higher phosphorylation of ARser81 (+87 ± 11%; p = 0.001) and ser515 (+55 ± 13%; p = 0.019). However, when the phosphorylated ratios were corrected for differences in total AR expression (i.e. our PI), the overall phosphorylation at these sites were similar between sexes (ser515, males = 100% vs females 92%; ser81, males = 100% vs females = 107%). pGRser134 was higher in males compared to females (+50 ± 15%; p = 0.016). Phospho-p38 was higher in females compared to males (+5050 ± 16%; p < 0.001). CONCLUSION At rest, ARs and GRs are differentially phosphorylated at some, but not all sites when comparing males and females. Differential regulation of phosphorylated AR, GR, and p38 between males and females may have implications for the degree of muscle adaptations observed following resistance or endurance training.
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Affiliation(s)
- Justin X Nicoll
- California State University Northridge, Department of Kinesiology, Northridge, CA, United States.
| | - Andrew C Fry
- University of Kansas, Department of Health, Sport and Exercise Sciences, Lawrence 66045, KS, United States.
| | - Eric M Mosier
- Northwest Missouri State University, School of Health Science and Wellness, Maryville 64468, MO, United States.
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27
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Modulation of the renin-angiotensin system in white adipose tissue and skeletal muscle: focus on exercise training. Clin Sci (Lond) 2018; 132:1487-1507. [PMID: 30037837 DOI: 10.1042/cs20180276] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 06/13/2018] [Accepted: 06/27/2018] [Indexed: 12/11/2022]
Abstract
Overactivation of the renin-angiotensin (Ang) system (RAS) increases the classical arm (Ang-converting enzyme (ACE)/Ang II/Ang type 1 receptor (AT1R)) to the detriment of the protective arm (ACE2/Ang 1-7/Mas receptor (MasR)). The components of the RAS are present locally in white adipose tissue (WAT) and skeletal muscle, which act co-operatively, through specific mediators, in response to pathophysiological changes. In WAT, up-regulation of the classical arm promotes lipogenesis and reduces lipolysis and adipogenesis, leading to adipocyte hypertrophy and lipid storage, which are related to insulin resistance and increased inflammation. In skeletal muscle, the classical arm promotes protein degradation and increases the inflammatory status and oxidative stress, leading to muscle wasting. Conversely, the protective arm plays a counter-regulatory role by opposing the effect of Ang II. The accumulation of adipose tissue and muscle mass loss is associated with a higher risk of morbidity and mortality, which could be related, in part, to overactivation of the RAS. On the other hand, exercise training (ExT) shifts the balance of the RAS towards the protective arm, promoting the inhibition of the classical arm in parallel with the stimulation of the protective arm. Thus, fat mobilization and maintenance of muscle mass and function are facilitated. However, the mechanisms underlying exercise-induced changes in the RAS remain unclear. In this review, we present the RAS as a key mechanism of WAT and skeletal muscle metabolic dysfunction. Furthermore, we discuss the interaction between the RAS and exercise and the possible underlying mechanisms of the health-related aspects of ExT.
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28
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Potential Roles of n-3 PUFAs during Skeletal Muscle Growth and Regeneration. Nutrients 2018; 10:nu10030309. [PMID: 29510597 PMCID: PMC5872727 DOI: 10.3390/nu10030309] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Revised: 03/01/2018] [Accepted: 03/02/2018] [Indexed: 01/06/2023] Open
Abstract
Omega-3 polyunsaturated fatty acids (n-3 PUFAs), which are commonly found in fish oil supplements, are known to possess anti-inflammatory properties and more recently alter skeletal muscle function. In this review, we discuss novel findings related to how n-3 PUFAs modulate molecular signaling responsible for growth and hypertrophy as well as the activity of muscle stem cells. Muscle stem cells commonly known as satellite cells, are primarily responsible for driving the skeletal muscle repair process to potentially damaging stimuli, such as mechanical stress elicited by exercise contraction. To date, there is a paucity of human investigations related to the effects of n-3 PUFAs on satellite cell content and activity. Based on current in vitro investigations, this review focuses on novel mechanisms linking n-3 PUFA’s to satellite cell activity and how they may improve muscle repair. Understanding the role of n-3 PUFAs during muscle growth and regeneration in association with exercise could lead to the development of novel supplementation strategies that increase muscle mass and strength, therefore possibly reducing the burden of muscle wasting with age.
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29
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Kim Y, Men SS, Liang C, Receno CN, Brutsaert TD, Korol DL, Heffernan KS, DeRuisseau KC. Effects of long-term exposures to low iron and branched-chain amino acid containing diets on aging skeletal muscle of Fisher 344 × Brown Norway rats. Appl Physiol Nutr Metab 2017; 43:165-173. [PMID: 29024598 DOI: 10.1139/apnm-2017-0272] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Aging skeletal muscle displays an altered iron status that may promote oxidative stress and sarcopenia. A diet containing low iron (LI) could reduce muscle iron status and attenuate age-related muscle atrophy. Supplemental branched-chain amino acids (BCAA) may also alleviate sarcopenia by promoting muscle protein synthesis and iron status improvement. This study examined individual and combined effects of LI and BCAA diets on anabolic signaling and iron status in skeletal muscle of aging rats. Twenty-nine-month-old male Fisher 344 × Brown Norway rats consumed the following control-base diets: control + regular iron (35 mg iron/kg) (CR; n = 11); control + LI (∼6 mg iron/kg) (CL; n = 11); 2×BCAA + regular iron (BR; n = 10); and 2×BCAA + LI (BL; n = 12) for 12 weeks. Although LI and/or 2×BCAA did not affect plantaris muscle mass, 2×BCAA groups showed lower muscle iron content than did CR and CL groups (P < 0.05). p70 ribosomal protein S6 kinase phosphorylation was greater in 2×BCAA and LI animals compared with CR animals (P < 0.05). Interactions between IRON and BCAA were observed for proteins indicative of mitochondrial biogenesis (peroxisome proliferator-activated receptor gamma coactivator 1 alpha) and oxidative capacity (cytochrome c oxidase subunit 2 and citrate synthase) (P < 0.05) wherein the combined diet (BL) negated potential benefits of individual diets. Antioxidant capacity, superoxide dismutase activity, and oxidative injury (3-nitrotyrosine, protein carbonyls, and 4-hydroxynonenal) were similar between groups. In conclusion, 12 weeks of LI and 2×BCAA diets showed significant impacts on increasing anabolic signaling as well as ameliorating iron status; however, these interventions did not affect muscle mass.
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Affiliation(s)
- Yuho Kim
- a Department of Exercise Science, Syracuse University, 820 Comstock Ave, Room 201 WB, Syracuse, NY 13244, USA.,b Muscle Energetics Laboratory, National Heart, Lung, and Blood Institute, 10 Center Drive Room B1D400, Bethesda, MD 20892, USA
| | - Sok Sambo Men
- c Department of Nutrition Science, Syracuse University, 426 Ostrom Avenue, Syracuse, NY 13244, USA
| | - Chen Liang
- d Department of Exercise Science, Syracuse University, 820 Comstock Ave., Room 201 WB, Syracuse, NY 13244, USA
| | - Candace N Receno
- d Department of Exercise Science, Syracuse University, 820 Comstock Ave., Room 201 WB, Syracuse, NY 13244, USA
| | - Tom D Brutsaert
- d Department of Exercise Science, Syracuse University, 820 Comstock Ave., Room 201 WB, Syracuse, NY 13244, USA
| | - Donna L Korol
- e Department of Biology, Syracuse University, 107 College Place, Syracuse, NY 13244, USA
| | - Kevin S Heffernan
- d Department of Exercise Science, Syracuse University, 820 Comstock Ave., Room 201 WB, Syracuse, NY 13244, USA
| | - Keith C DeRuisseau
- d Department of Exercise Science, Syracuse University, 820 Comstock Ave., Room 201 WB, Syracuse, NY 13244, USA
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30
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Lu Y, Bradley JS, McCoski SR, Gonzalez JM, Ealy AD, Johnson SE. Reduced skeletal muscle fiber size following caloric restriction is associated with calpain-mediated proteolysis and attenuation of IGF-1 signaling. Am J Physiol Regul Integr Comp Physiol 2017; 312:R806-R815. [PMID: 28228415 DOI: 10.1152/ajpregu.00400.2016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 02/15/2017] [Accepted: 02/16/2017] [Indexed: 01/24/2023]
Abstract
Caloric restriction decreases skeletal muscle mass in mammals, principally due to a reduction in fiber size. The effect of suboptimal nutrient intake on skeletal muscle metabolic properties in neonatal calves was examined. The longissimus muscle (LM) was collected after a control (CON) or caloric restricted (CR) diet was cosnumed for 8 wk and muscle fiber size, gene expression, and metabolic signal transduction activity were measured. Results revealed that CR animals had smaller (P < 0.05) LM fiber cross-sectional area than CON, as expected. Western blot analysis detected equivalent amounts of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC1α) but reduced (P < 0.05) amounts of the splice-variant, PGC1α-4 in CR LM. Expression of IGF-1, a PGC1α-4 target gene, was 40% less (P < 0.05) in CR than CON. Downstream mediators of autocrine IGF-1 signaling also are attenuated in CR by comparison with CON. The amount of phosphorylated AKT1 was less (P < 0.05) in CR than CON. The ratio of p4EBP1T37/46 to total 4EBP1, a downstream mediator of AKT1, did not differ between CON and CR. By contrast, protein lysates from CR LM contained less (P < 0.05) total glycogen synthase kinase-3β (GSK3β) and phosphorylated GSK3β than CON LM, suggesting blunted protein synthesis. Smaller CR LM fiber size associates with increased (P < 0.05) calpain 1 (CAPN1) activity coupled with lower (P < 0.05) expression of calpastatin, the endogenous inhibitor of CAPN1. Atrogin-1 and MuRF expression and autophagy components were unaffected by CR. Thus CR suppresses the hypertrophic PGC1α-4/IGF-1/AKT1 pathway while promoting activation of the calpain system.
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Affiliation(s)
- Yue Lu
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg Virginia; and
| | - Jennifer S Bradley
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg Virginia; and
| | - Sarah R McCoski
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg Virginia; and
| | - John M Gonzalez
- Department of Animal Sciences and Industry, Kansas State University, Manhattan, Kansas
| | - Alan D Ealy
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg Virginia; and
| | - Sally E Johnson
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg Virginia; and
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Seabra AD, Moraes SAS, Batista EJO, Garcia TB, Souza MC, Oliveira KRM, Herculano AM. Local inhibition of nitrergic activity in tenotomized rats accelerates muscle regeneration by increasing fiber area and decreasing central core lesions. ACTA ACUST UNITED AC 2017; 50:e5556. [PMID: 28225888 PMCID: PMC5333718 DOI: 10.1590/1414-431x20165556] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Accepted: 12/02/2016] [Indexed: 11/22/2022]
Abstract
Muscular atrophy is a progressive degeneration characterized by muscular proteolysis, loss of mass and decrease in fiber area. Tendon rupture induces muscular atrophy due to an intrinsic functional connection. Local inhibition of nitric oxide synthase (NOS) by Nω-nitro-L-arginine methyl ester (L-NAME) accelerates tendon histological recovery and induces functional improvement. Here we evaluate the effects of such local nitrergic inhibition on the pattern of soleus muscle regeneration after tenotomy. Adult male Wistar rats (240 to 280 g) were divided into four experimental groups: control (n=4), tenotomized (n=6), vehicle (n=6), and L-NAME (n=6). Muscular atrophy was induced by calcaneal tendon rupture in rats. Changes in muscle wet weight and total protein levels were determined by the Bradford method, and muscle fiber area and central core lesion (CCL) occurrence were evaluated by histochemical assays. Compared to tenotomized (69.3±22%) and vehicle groups (68.1%±17%), L-NAME treatment induced an increase in total protein level (108.3±21%) after 21 days post-injury. A reduction in fiber areas was observed in tenotomized (56.3±1.3%) and vehicle groups (53.9±3.9%). However, L-NAME treatment caused an increase in this parameter (69.3±1.6%). Such events were preceded by a remarkable reduction in the number of fibers with CCL in L-NAME-treated animals (12±2%), but not in tenotomized (21±2.5%) and vehicle groups (19.6±2.8%). Altogether, our data reveal that inhibition of tendon NOS contributed to the attenuation of atrophy and acceleration of muscle regeneration.
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Affiliation(s)
- A D Seabra
- Laboratório de Neurofarmacologia Experimental, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA, Brasil
| | - S A S Moraes
- Laboratório de Neurofarmacologia Experimental, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA, Brasil
| | - E J O Batista
- Núcleo de Medicina Tropical, Universidade Federal do Pará, Belém, PA, Brasil
| | - T B Garcia
- Laboratório de Neurofarmacologia Experimental, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA, Brasil
| | - M C Souza
- Laboratório de Neurofarmacologia Experimental, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA, Brasil
| | - K R M Oliveira
- Laboratório de Neurofarmacologia Experimental, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA, Brasil
| | - A M Herculano
- Laboratório de Neurofarmacologia Experimental, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA, Brasil
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Pharmacological Inhibition of c-Jun N-terminal Kinase Reduces Food Intake and Sensitizes Leptin's Anorectic Signaling Actions. Sci Rep 2017; 7:41795. [PMID: 28165482 PMCID: PMC5292945 DOI: 10.1038/srep41795] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 12/28/2016] [Indexed: 01/09/2023] Open
Abstract
The role for c-Jun N-terminal Kinase (JNK) in the control of feeding and energy balance is not well understood. Here, by use of novel and highly selective JNK inhibitors, we investigated the actions of JNK in the control of feeding and body weight homeostasis. In lean mice, intraperitoneal (i.p.) or intracerebroventricular (i.c.v.) administration of SR-3306, a brain-penetrant and selective pan-JNK (JNK1/2/3) inhibitor, reduced food intake and body weight. Moreover, i.p. and i.c.v. administrations of SR11935, a brain-penetrant and JNK2/3 isoform-selective inhibitor, exerted similar anorectic effects as SR3306, which suggests JNK2 or JNK3 mediates aspect of the anorectic effect by pan-JNK inhibition. Furthermore, daily i.p. injection of SR3306 (7 days) prevented the increases in food intake and weight gain in lean mice upon high-fat diet feeding, and this injection paradigm reduced high-fat intake and obesity in diet-induced obese (DIO) mice. In the DIO mice, JNK inhibition sensitized leptin’s anorectic effect, and enhanced leptin-induced STAT3 activation in the hypothalamus. The underlying mechanisms likely involve the downregulation of SOCS3 by JNK inhibition. Collectively, our data suggest that JNK activity promotes positive energy balance, and the therapeutic intervention inhibiting JNK activities represents a promising approach to ameliorate diet-induced obesity and leptin resistance.
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Miller WP, Ravi S, Martin TD, Kimball SR, Dennis MD. Activation of the Stress Response Kinase JNK (c-Jun N-terminal Kinase) Attenuates Insulin Action in Retina through a p70S6K1-dependent Mechanism. J Biol Chem 2016; 292:1591-1602. [PMID: 27965359 DOI: 10.1074/jbc.m116.760868] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 10/28/2016] [Indexed: 01/14/2023] Open
Abstract
Despite recent advances in therapeutics, diabetic retinopathy remains a leading cause of vision impairment. Improvement in the treatment of diabetic retinopathy requires a better understanding of the molecular mechanisms that cause neurovascular complications, particularly in type 2 diabetes. Recent studies demonstrate that rodents fed a high fat diet exhibit retinal dysfunction concomitant with attenuated Akt phosphorylation. The purpose of the present study was to evaluate the impact of a high fat/high sucrose diet on retinal insulin signaling and evaluate the mechanism(s) responsible for the changes. Mice fed a high fat/sucrose diet exhibited attenuated Akt phosphorylation in the retina as compared with mice fed normal chow. Retinas of mice fed a high fat/sucrose diet also exhibited elevated levels of activated JNK as well as enhanced p70S6K1 autoinhibitory domain phosphorylation. In cells, JNK activation enhanced p70S6K1 phosphorylation and mTORC1-dependent activation of the kinase, as evidenced by enhanced phosphorylation of key substrates. Rictor phosphorylation by p70S6K1 was specifically enhanced by the addition of phosphomimetic mutations in the autoinhibitory domain and was more sensitive to inhibition of the kinase as compared with rpS6. Notably, rictor and IRS-1 phosphorylation by p70S6K1 attenuate insulin action through a negative feedback pathway. Indeed, p70S6K1 inhibition prevented the repressive effect of JNK activation on insulin action in retinas. Overall, the results identify the JNK/S6K1 axis as a key molecular mechanism whereby a high fat/sucrose diet impairs insulin action in retina.
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Affiliation(s)
- William P Miller
- From the Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033
| | - Suhana Ravi
- From the Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033
| | - Tony D Martin
- From the Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033
| | - Scot R Kimball
- From the Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033
| | - Michael D Dennis
- From the Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033.
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Ichinose T, Yamamoto A, Kobayashi T, Shitara H, Shimoyama D, Iizuka H, Koibuchi N, Takagishi K. Compensatory hypertrophy of the teres minor muscle after large rotator cuff tear model in adult male rat. J Shoulder Elbow Surg 2016; 25:316-21. [PMID: 26422529 DOI: 10.1016/j.jse.2015.07.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 07/29/2015] [Accepted: 07/30/2015] [Indexed: 02/01/2023]
Abstract
BACKGROUND Rotator cuff tear (RCT) is a common musculoskeletal disorder in the elderly. The large RCT is often irreparable due to the retraction and degeneration of the rotator cuff muscle. The integrity of the teres minor (TM) muscle is thought to affect postoperative functional recovery in some surgical treatments. Hypertrophy of the TM is found in some patients with large RCTs; however, the process underlying this hypertrophy is still unclear. The objective of this study was to determine if compensatory hypertrophy of the TM muscle occurs in a large RCT rat model. METHODS Twelve Wistar rats underwent transection of the suprascapular nerve and the supraspinatus and infraspinatus tendons in the left shoulder. The rats were euthanized 4 weeks after the surgery, and the cuff muscles were collected and weighed. The cross-sectional area and the involvement of Akt/mammalian target of rapamycin (mTOR) signaling were examined in the remaining TM muscle. RESULTS The weight and cross-sectional area of the TM muscle was higher in the operated-on side than in the control side. The phosphorylated Akt/Akt protein ratio was not significantly different between these sides. The phosphorylated-mTOR/mTOR protein ratio was significantly higher on the operated-on side. CONCLUSION Transection of the suprascapular nerve and the supraspinatus and infraspinatus tendons activates mTOR signaling in the TM muscle, which results in muscle hypertrophy. The Akt-signaling pathway may not be involved in this process. Nevertheless, activation of mTOR signaling in the TM muscle after RCT may be an effective therapeutic target of a large RCT.
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Affiliation(s)
- Tsuyoshi Ichinose
- Department of Orthopaedic Surgery, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan.
| | - Atsushi Yamamoto
- Department of Orthopaedic Surgery, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
| | - Tsutomu Kobayashi
- Department of Physical Therapy, Takasaki University of Health and Welfare, Takasaki, Gunma, Japan
| | - Hitoshi Shitara
- Department of Orthopaedic Surgery, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
| | - Daisuke Shimoyama
- Department of Orthopaedic Surgery, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
| | - Haku Iizuka
- Department of Orthopaedic Surgery, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
| | - Noriyuki Koibuchi
- Department of Integrative Physiology, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
| | - Kenji Takagishi
- Department of Orthopaedic Surgery, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
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Russ DW, Acksel C, Boyd IM, Maynard J, McCorkle KW, Edens NK, Garvey SM. Dietary HMB and β-alanine co-supplementation does not improve in situ muscle function in sedentary, aged male rats. Appl Physiol Nutr Metab 2015; 40:1294-301. [PMID: 26579948 DOI: 10.1139/apnm-2015-0391] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
This study evaluated the effects of dietary β-hydroxy-β-methylbutyrate (HMB) combined with β-alanine (β-Ala) in sedentary, aged male rats. It has been suggested that dietary HMB or β-Ala supplementation may mitigate age-related declines in muscle strength and fatigue resistance. A total of 20 aged Sprague-Dawley rats were studied. At age 20 months, 10 rats were administered a control, purified diet and 10 rats were administered a purified diet supplemented with both HMB and β-Ala (HMB+β-Ala) for 8 weeks (approximately equivalent to 3 and 2.4 g per day human dose). We measured medial gastrocnemius (MG) size, force, fatigability, and myosin composition. We also evaluated an array of protein markers related to muscle mitochondria, protein synthesis and breakdown, and autophagy. HMB+β-Ala had no significant effects on body weight, MG mass, force or fatigability, myosin composition, or muscle quality. Compared with control rats, those fed HMB+β-Ala exhibited a reduced (41%, P = 0.039) expression of muscle RING-finger protein 1 (MURF1), a common marker of protein degradation. Muscle from rats fed HMB+β-Ala also exhibited a 45% reduction (P = 0.023) in p70s6K phosphorylation following fatiguing stimulation. These data suggest that HMB+β-Ala at the dose studied may reduce muscle protein breakdown by reducing MURF1 expression, but has minimal effects on muscle function in this model of uncomplicated aging. They do not, however, rule out potential benefits of HMB+β-Ala co-supplementation at other doses or durations of supplementation in combination with exercise or in situations where extreme muscle protein breakdown and loss of mass occur (e.g., bedrest, cachexia, failure-to-thrive).
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Affiliation(s)
- David W Russ
- a Laboratory for Integrative Muscle Biology, Division of Physical Therapy, School of Rehabilitation and Communication Sciences, Ohio University, Athens, OH 45701, USA.,b Ohio Musculoskeletal and Neurological Institute (OMNI), Heritage College of Osteopathic Medicine, Athens, OH 45701, USA
| | - Cara Acksel
- a Laboratory for Integrative Muscle Biology, Division of Physical Therapy, School of Rehabilitation and Communication Sciences, Ohio University, Athens, OH 45701, USA.,c Division of Nutrition, School of Applied Health Sciences and Wellness, Ohio University, Athens, OH 45701, USA
| | - Iva M Boyd
- a Laboratory for Integrative Muscle Biology, Division of Physical Therapy, School of Rehabilitation and Communication Sciences, Ohio University, Athens, OH 45701, USA
| | - John Maynard
- a Laboratory for Integrative Muscle Biology, Division of Physical Therapy, School of Rehabilitation and Communication Sciences, Ohio University, Athens, OH 45701, USA
| | - Katherine W McCorkle
- a Laboratory for Integrative Muscle Biology, Division of Physical Therapy, School of Rehabilitation and Communication Sciences, Ohio University, Athens, OH 45701, USA
| | - Neile K Edens
- d Abbott Nutrition R&D, 3300 Stelzer Road, Columbus, OH 43219, USA
| | - Sean M Garvey
- d Abbott Nutrition R&D, 3300 Stelzer Road, Columbus, OH 43219, USA
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Paulsen G, Hamarsland H, Cumming KT, Johansen RE, Hulmi JJ, Børsheim E, Wiig H, Garthe I, Raastad T. Vitamin C and E supplementation alters protein signalling after a strength training session, but not muscle growth during 10 weeks of training. J Physiol 2014; 592:5391-408. [PMID: 25384788 DOI: 10.1113/jphysiol.2014.279950] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
This study investigated the effects of vitamin C and E supplementation on acute responses and adaptations to strength training. Thirty-two recreationally strength-trained men and women were randomly allocated to receive a vitamin C and E supplement (1000 mg day(-1) and 235 mg day(-1), respectively), or a placebo, for 10 weeks. During this period the participants' training involved heavy-load resistance exercise four times per week. Muscle biopsies from m. vastus lateralis were collected, and 1 repetition maximum (1RM) and maximal isometric voluntary contraction force, body composition (dual-energy X-ray absorptiometry), and muscle cross-sectional area (magnetic resonance imaging) were measured before and after the intervention. Furthermore, the cellular responses to a single exercise session were assessed midway in the training period by measurements of muscle protein fractional synthetic rate and phosphorylation of several hypertrophic signalling proteins. Muscle biopsies were obtained from m. vastus lateralis twice before, and 100 and 150 min after, the exercise session (4 × 8RM, leg press and knee-extension). The supplementation did not affect the increase in muscle mass or the acute change in protein synthesis, but it hampered certain strength increases (biceps curl). Moreover, increased phosphorylation of p38 mitogen-activated protein kinase, Extracellular signal-regulated protein kinases 1 and 2 and p70S6 kinase after the exercise session was blunted by vitamin C and E supplementation. The total ubiquitination levels after the exercise session, however, were lower with vitamin C and E than placebo. We concluded that vitamin C and E supplementation interfered with the acute cellular response to heavy-load resistance exercise and demonstrated tentative long-term negative effects on adaptation to strength training.
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Affiliation(s)
- G Paulsen
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway Norwegian Olympic Federation, Oslo, Norway
| | - H Hamarsland
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| | - K T Cumming
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| | - R E Johansen
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| | - J J Hulmi
- Department of Biology of Physical Activity, Neuromuscular Research Center, University of Jyväskylä, Jyväskylä, Finland
| | - E Børsheim
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway Arkansas Children's Hospital Research Institute, Departments of Pediatrics and Geriatrics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - H Wiig
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| | - I Garthe
- Norwegian Olympic Federation, Oslo, Norway
| | - T Raastad
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
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