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Abdalla-Silva RL, Zanetti GO, Lautherbach N, Schavinski AZ, Heck LC, Gonçalves DAP, Kettelhut IC, Navegantes LCC, Silveira WA. β 2-Adrenoceptors activation regulates muscle trophic-related genes following acute resistance exercise in mice. Front Physiol 2024; 15:1268380. [PMID: 38318197 PMCID: PMC10839027 DOI: 10.3389/fphys.2024.1268380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 01/08/2024] [Indexed: 02/07/2024] Open
Abstract
Resistance exercise (RE) training and pharmacological stimulation of β2-Adrenoceptors (β2-ARs) alone can promote muscle hypertrophy and prevent muscle atrophy. Although the activation of the sympathetic nervous system (SNS) is a well-established response during RE, the physiological contribution of the endogenous catecholamines and β2-ARs to the RE-induced changes on skeletal muscle protein metabolism remains unclear. This study investigated the effects of the β2-ARs blockade on the acute molecular responses induced by a single bout of RE in rodent skeletal muscles. Male C57BL6/J mice were subjected to a single bout of progressive RE (until exhaustion) on a vertical ladder under β2-AR blockade with ICI 118,551 (ICI; 10 mg kg-1, i. p.), or vehicle (sterile saline; 0.9%, i. p.), and the gene expression was analyzed in gastrocnemius (GAS) muscles by qPCR. We demonstrated that a single bout of RE acutely increased the circulating levels of stress-associated hormones norepinephrine (NE) and corticosterone (CORT), as well as the muscle phosphorylation levels of AMPK, p38 MAPK and CREB, immediately after the session. The acute increase in the phosphorylation levels of CREB was followed by the upregulation of CREB-target genes Sik1, Ppargc1a and Nr4a3 (a central regulator of the acute RE response), 3 h after the RE session. Conversely, β2-AR blockade reduced significantly the Sik1 and Nr4a3 mRNA levels in muscles of exercised mice. Furthermore, a single bout of RE stimulated the mRNA levels of the atrophic genes Map1lc3b and Gabarapl1 (autophagy-related genes) and Mstn (a well-known negative regulator of muscle growth). Unexpectedly, the gene expression of Igf-1 or Il-6 were not affected by RE, while the atrophic genes Murf1/Trim63 and Atrogin-1/Mafbx32 (ubiquitin-ligases) were increased only in muscles of exercised mice under β2-AR blockade. Interestingly, performing a single bout of RE under β2-AR blockade increased the mRNA levels of Mstn in muscles of exercised mice. These data suggest that β2-ARs stimulation during acute RE stimulates the hypertrophic gene Nr4a3 and prevents the overexpression of atrophic genes such as Mstn, Murf1/Trim63, and Atrogin-1/Mafbx32 in the first hours of postexercise recovery, indicating that he SNS may be physiologically important to muscle adaptations in response to resistance training.
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Affiliation(s)
- Ronaldo L. Abdalla-Silva
- Department of Biochemistry, Pharmacology and Physiology, Institute of Biological and Natural Sciences, Federal University of Triângulo Mineiro, Uberaba, Minas Gerais, Brazil
| | - Gustavo O. Zanetti
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Natalia Lautherbach
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
- Department of Biochemistry/Immunology, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Aline Zanatta Schavinski
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Lilian C. Heck
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Dawit A. P. Gonçalves
- Exercise Physiology Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- Sports Training Center, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Isis C. Kettelhut
- Department of Biochemistry/Immunology, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Luiz C. C. Navegantes
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Wilian A. Silveira
- Department of Biochemistry, Pharmacology and Physiology, Institute of Biological and Natural Sciences, Federal University of Triângulo Mineiro, Uberaba, Minas Gerais, Brazil
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Hostrup M, Jessen S. Beyond bronchodilation: Illuminating the performance benefits of inhaled beta 2 -agonists in sports. Scand J Med Sci Sports 2024; 34:e14567. [PMID: 38268072 DOI: 10.1111/sms.14567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 12/29/2023] [Accepted: 01/06/2024] [Indexed: 01/26/2024]
Abstract
Given the prevalent use of inhaled beta2 -agonists in sports, there is an ongoing debate as to whether they enhance athletic performance. Over the last decades, inhaled beta2 -agonists have been claimed not to enhance performance with little consideration of dose or exercise modality. In contrast, orally administered beta2 -agonists are perceived as being performance enhancing, predominantly on muscle strength and sprint ability, but can also induce muscle hypertrophy and slow-to-fast fiber phenotypic switching. But because inhaled beta2 -agonists are more efficient to achieve high systemic concentrations than oral delivery relative to dose, it follows that the inhaled route has the potential to enhance performance too. The question is at which inhaled doses such effects occur. While supratherapeutic doses of inhaled beta2 -agonists enhance muscle strength and short intense exercise performance, effects at low therapeutic doses are less apparent. However, even high therapeutic inhaled doses of commonly used beta2 -agonists have been shown to induce muscle hypertrophy and to enhance sprint performance. This is concerning from an anti-doping perspective. In this paper, we raise awareness of the circumstances under which inhaled beta2 -agonists can constitute a performance-enhancing benefit.
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Affiliation(s)
- Morten Hostrup
- Department of Nutrition, Exercise and Sports, The August Krogh Section for Human Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Søren Jessen
- Department of Nutrition, Exercise and Sports, The August Krogh Section for Human Physiology, University of Copenhagen, Copenhagen, Denmark
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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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Kumar A, Prajapati P, Singh G, Kumar D, Mishra V, Kim SC, Raorane CJ, Raj V, Kushwaha S. Salbutamol Attenuates Diabetic Skeletal Muscle Atrophy by Reducing Oxidative Stress, Myostatin/GDF-8, and Pro-Inflammatory Cytokines in Rats. Pharmaceutics 2023; 15:2101. [PMID: 37631314 PMCID: PMC10458056 DOI: 10.3390/pharmaceutics15082101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 08/02/2023] [Accepted: 08/02/2023] [Indexed: 08/27/2023] Open
Abstract
Type 2 diabetes is a metabolic disorder that leads to accelerated skeletal muscle atrophy. In this study, we aimed to evaluate the effect of salbutamol (SLB) on skeletal muscle atrophy in high-fat diet (HFD)/streptozotocin (STZ)-induced diabetic rats. Male Sprague Dawley rats were divided into four groups (n = 6): control, SLB, HFD/STZ, and HFD/STZ + SLB (6 mg/kg orally for four weeks). After the last dose of SLB, rats were assessed for muscle grip strength and muscle coordination (wire-hanging, rotarod, footprint, and actophotometer tests). Body composition was analyzed in live rats. After that, animals were sacrificed, and serum and gastrocnemius (GN) muscles were collected. Endpoints include myofibrillar protein content, muscle oxidative stress and antioxidants, serum pro-inflammatory cytokines (interleukin-1β, interleukin-2, and interleukin-6), serum muscle markers (myostatin, creatine kinase, and testosterone), histopathology, and muscle 1H NMR metabolomics. Findings showed that SLB treatment significantly improved muscle strength and muscle coordination, as well as increased lean muscle mass in diabetic rats. Increased pro-inflammatory cytokines and muscle markers (myostatin, creatine kinase) indicate muscle deterioration in diabetic rats, while SLB intervention restored the same. Also, Feret's diameter and cross-sectional area of GN muscle were increased by SLB treatment, indicating the amelioration in diabetic rat muscle. Results of muscle metabolomics exhibit that SLB treatment resulted in the restoration of perturbed metabolites, including histidine-to-tyrosine, phenylalanine-to-tyrosine, and glutamate-to-glutamine ratios and succinate, sarcosine, and 3-hydroxybutyrate (3HB) in diabetic rats. These metabolites showed a pertinent role in muscle inflammation and oxidative stress in diabetic rats. In conclusion, findings showed that salbutamol could be explored as an intervention in diabetic-associated skeletal muscle atrophy.
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Affiliation(s)
- Anand Kumar
- Department of Pharmaceutical Sciences, School of Pharmaceutical Sciences, Babasaheb Bhimrao Ambedkar University, Vidya Vihar, Raebareli Road, Lucknow 226025, India; (A.K.); (P.P.); (V.M.)
| | - Priyanka Prajapati
- Department of Pharmaceutical Sciences, School of Pharmaceutical Sciences, Babasaheb Bhimrao Ambedkar University, Vidya Vihar, Raebareli Road, Lucknow 226025, India; (A.K.); (P.P.); (V.M.)
| | - Gurvinder Singh
- Centre of Biomedical Research, SGPGIMS Campus, Lucknow 226014, India; (G.S.); (D.K.)
| | - Dinesh Kumar
- Centre of Biomedical Research, SGPGIMS Campus, Lucknow 226014, India; (G.S.); (D.K.)
| | - Vikas Mishra
- Department of Pharmaceutical Sciences, School of Pharmaceutical Sciences, Babasaheb Bhimrao Ambedkar University, Vidya Vihar, Raebareli Road, Lucknow 226025, India; (A.K.); (P.P.); (V.M.)
| | - Seong-Cheol Kim
- School of Chemical Engineering, Yeungnam University, Gyeongsan 38541, Republic of Korea;
| | | | - Vinit Raj
- School of Chemical Engineering, Yeungnam University, Gyeongsan 38541, Republic of Korea;
| | - Sapana Kushwaha
- National Institute of Pharmaceutical Education and Research (NIPER), Raebareli, New Transit Campus, Bijnor-Sisendi Road, Lucknow 226002, India
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5
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Dalle S, Schouten M, Ramaekers M, Koppo K. The cannabinoid receptor 1 antagonist AM6545 stimulates the Akt-mTOR axis and in vivo muscle protein synthesis in a dexamethasone-induced muscle atrophy model. Mol Cell Endocrinol 2023; 563:111854. [PMID: 36682621 DOI: 10.1016/j.mce.2023.111854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 12/14/2022] [Accepted: 01/12/2023] [Indexed: 01/21/2023]
Abstract
Cannabinoid receptor 1 (CB1) antagonists were shown to stimulate in vitro muscle protein synthesis, but this has never been confirmed in vivo. Therefore, this study investigated whether treatment with the CB1 antagonist AM6545 upregulates in vivo muscle anabolism. Chronic AM6545 treatment stimulated the Akt-mTOR axis and protein synthesis (+22%; p = 0.002) in the Tibialis Anterior, which protected mice from dexamethasone-induced muscle loss (-1% vs. -6% compared to healthy controls; p = 0.02). Accordingly, acute AM6545 treatment stimulated protein synthesis (+44%; p = 0.04) in the Tibialis Anterior but not Soleus. The anabolic upregulation was accompanied by ERK1/2 activation, whereas protein kinase A signaling remained unaffected, suggesting a CB1-independent mechanism. The present study for the first time shows that the CB1 antagonist AM6545 can upregulate the Akt-mTOR axis and in vivo muscle protein synthesis. However, future work applying genetic approaches should further uncover the signaling pathways via which AM6545 enhances muscle anabolism.
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Affiliation(s)
- Sebastiaan Dalle
- Exercise Physiology Research Group, Department of Movement Sciences, KU Leuven, Tervuursevest 101, 3001, Leuven, Belgium.
| | - Moniek Schouten
- Exercise Physiology Research Group, Department of Movement Sciences, KU Leuven, Tervuursevest 101, 3001, Leuven, Belgium.
| | - Monique Ramaekers
- Exercise Physiology Research Group, Department of Movement Sciences, KU Leuven, Tervuursevest 101, 3001, Leuven, Belgium.
| | - Katrien Koppo
- Exercise Physiology Research Group, Department of Movement Sciences, KU Leuven, Tervuursevest 101, 3001, Leuven, Belgium.
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6
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McFaline-Figueroa J, Schifino AG, Nichenko AS, Lord MN, Hunda ET, Winders EA, Noble EE, Greising SM, Call JA. Pharmaceutical Agents for Contractile-Metabolic Dysfunction After Volumetric Muscle Loss. Tissue Eng Part A 2022; 28:795-806. [PMID: 35620911 PMCID: PMC9634984 DOI: 10.1089/ten.tea.2022.0036] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 04/21/2022] [Indexed: 11/12/2022] Open
Abstract
Volumetric muscle loss (VML) injuries represent a majority of military service member casualties and are common in civilian populations following blunt and/or penetrating traumas. Characterized as a skeletal muscle injury with permanent functional impairments, there is currently no standard for rehabilitation, leading to lifelong disability. Toward developing rehabilitative strategies, previous research demonstrates that the remaining muscle after a VML injury lacks similar levels of plasticity or adaptability as healthy, uninjured skeletal muscle. This may be due, in part, to impaired innervation and vascularization of the remaining muscle, as well as disrupted molecular signaling cascades commonly associated with muscle adaptation. The primary objective of this study was to assess the ability of four pharmacological agents with a strong record of modulating muscle contractile and metabolic function to improve functional deficits in a murine model of VML injury. Male C57BL/6 mice underwent a 15% multimuscle VML injury of the posterior hindlimb and were randomized into drug treatment groups (formoterol [FOR], 5-aminoimidazole-4-carboxamide riboside [AICAR], pioglitazone [PIO], or sildenafil [SIL]) or untreated VML group. At the end of 60 days, the injury model was first validated by comparison to age-matched injury-naive mice. Untreated VML mice had 22% less gastrocnemius muscle mass, 36% less peak-isometric torque, and 27% less maximal mitochondrial oxygen consumption rate compared to uninjured mice (p < 0.01). Experimental drug groups were, then, compared to VML untreated, and there was minimal evidence of efficacy for AICAR, PIO, or SIL in improving contractile and metabolic functional outcomes. However, FOR-treated VML mice had 18% greater peak isometric torque (p < 0.01) and permeabilized muscle fibers had 36% greater State III mitochondrial oxygen consumption rate (p < 0.01) compared to VML untreated mice, suggesting an overall improvement in muscle condition. There was minimal evidence that these benefits came from greater mitochondrial biogenesis and/or mitochondrial complex protein content, but could be due to greater enzyme activity levels for complex I and complex II. These findings suggest that FOR treatment is candidate to pair with a rehabilitative approach to maximize functional improvements in VML-injured muscle. Impact statement Volumetric muscle loss (VML) injuries result in deficiencies in strength and mobility, which have a severe impact on patient quality of life. Despite breakthroughs in tissue engineering, there are currently no treatments available that can restore function to the affected limb. Our data show that treatment of VML injuries with clinically available and FDA-approved formoterol (FOR), a beta-agonist, significantly improves strength and metabolism of VML-injured muscle. FOR is therefore a promising candidate for combined therapeutic approaches (i.e., regenerative rehabilitation) such as pairing FOR with structured rehabilitation or cell-seeded biomaterials as it may provide greater functional improvements than either strategy alone.
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Affiliation(s)
- Jennifer McFaline-Figueroa
- Department of Physiology & Pharmacology, University of Georgia, Athens, Georgia, USA
- Regenerative Bioscience Center, University of Georgia, Athens, Georgia, USA
| | - Albino G. Schifino
- Department of Physiology & Pharmacology, University of Georgia, Athens, Georgia, USA
- Regenerative Bioscience Center, University of Georgia, Athens, Georgia, USA
| | - Anna S. Nichenko
- Department of Physiology & Pharmacology, University of Georgia, Athens, Georgia, USA
- Regenerative Bioscience Center, University of Georgia, Athens, Georgia, USA
| | - Magen N. Lord
- Department of Nutritional Sciences, University of Georgia, Athens, Georgia, USA
| | - Edward T. Hunda
- Regenerative Bioscience Center, University of Georgia, Athens, Georgia, USA
| | | | - Emily E. Noble
- Department of Nutritional Sciences, University of Georgia, Athens, Georgia, USA
| | - Sarah M. Greising
- School of Kinesiology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Jarrod A. Call
- Department of Physiology & Pharmacology, University of Georgia, Athens, Georgia, USA
- Regenerative Bioscience Center, University of Georgia, Athens, Georgia, USA
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7
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Dalle S, Schouten M, Meeus G, Slagmolen L, Koppo K. Molecular networks underlying cannabinoid signaling in skeletal muscle plasticity. J Cell Physiol 2022; 237:3517-3540. [PMID: 35862111 DOI: 10.1002/jcp.30837] [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: 04/13/2022] [Revised: 07/01/2022] [Accepted: 07/08/2022] [Indexed: 11/07/2022]
Abstract
The cannabinoid system is ubiquitously present and is classically considered to engage in neural and immunity processes. Yet, the role of the cannabinoid system in the whole body and tissue metabolism via central and peripheral mechanisms is increasingly recognized. The present review provides insights in (i) how cannabinoid signaling is regulated via receptor-independent and -dependent mechanisms and (ii) how these signaling cascades (might) affect skeletal muscle plasticity and physiology. Receptor-independent mechanisms include endocannabinoid metabolism to eicosanoids and the regulation of ion channels. Alternatively, endocannabinoids can act as ligands for different classic (cannabinoid receptor 1 [CB1 ], CB2 ) and/or alternative (e.g., TRPV1, GPR55) cannabinoid receptors with a unique affinity, specificity, and intracellular signaling cascade (often tissue-specific). Antagonism of CB1 might hold clues to improve oxidative (mitochondrial) metabolism, insulin sensitivity, satellite cell growth, and muscle anabolism, whereas CB2 agonism might be a promising way to stimulate muscle metabolism and muscle cell growth. Besides, CB2 ameliorates muscle regeneration via macrophage polarization toward an anti-inflammatory phenotype, induction of MyoD and myogenin expression and antifibrotic mechanisms. Also TRPV1 and GPR55 contribute to the regulation of muscle growth and metabolism. Future studies should reveal how the cannabinoid system can be targeted to improve muscle quantity and/or quality in conditions such as ageing, disease, disuse, and metabolic dysregulation, taking into account challenges that are inherent to modulation of the cannabinoid system, such as central and peripheral side effects.
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Affiliation(s)
- Sebastiaan Dalle
- Department of Movement Sciences, Exercise Physiology Research Group, KU Leuven, Leuven, Belgium
| | - Moniek Schouten
- Department of Movement Sciences, Exercise Physiology Research Group, KU Leuven, Leuven, Belgium
| | - Gitte Meeus
- Department of Movement Sciences, Exercise Physiology Research Group, KU Leuven, Leuven, Belgium
| | - Lotte Slagmolen
- Department of Movement Sciences, Exercise Physiology Research Group, KU Leuven, Leuven, Belgium
| | - Katrien Koppo
- Department of Movement Sciences, Exercise Physiology Research Group, KU Leuven, Leuven, Belgium
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8
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Hostrup M, Knudsen JG, Kristensen CM, Jessen S, Pilegaard H, Bangsbo J. Beta 2 -agonist increases skeletal muscle interleukin 6 production and release in response to resistance exercise in men. Scand J Med Sci Sports 2022; 32:1099-1108. [PMID: 35460295 PMCID: PMC9545867 DOI: 10.1111/sms.14171] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 04/19/2022] [Accepted: 04/20/2022] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Several tissues produce and release interleukin-6 (IL-6) in response to beta2 -adrenergic stimulation with selective agonists (beta2 -agonists). Moreover, exercise stimulates muscle IL-6 production, but whether beta2 -agonists regulate skeletal muscle production and release of IL-6 in humans in association with exercise remains to be clarified. Thus, we investigated leg IL-6 release in response to beta2 -agonist salbutamol in lean young men at rest and in recovery from resistance exercise. DESIGN The study employed a randomized controlled crossover design, where 12 men ingested either salbutamol (16 mg) or placebo for 4 days, followed by the last dose (24 mg) administered 1½ h before exercise. Arterial and femoral venous plasma IL-6 as well as femoral artery blood flow was measured before and ½-5 h in recovery from quadriceps muscle resistance exercise. Furthermore, vastus lateralis muscle biopsies were collected ½ and 5 h after exercise for determination of mRNA levels of IL-6 and Tumor Necrosis Factor (TNF)-α. RESULTS Average leg IL-6 release was 1.7-fold higher (p = 0.01) for salbutamol than placebo, being 138 ± 76 and 79 ± 66 pg min-1 (mean ± SD) for salbutamol and placebo, respectively, but IL-6 release was not significantly different between treatments within specific sampling points at rest and after exercise. Muscle IL-6 mRNA was 1.5- and 1.7-fold higher (p = 0.001) for salbutamol than placebo ½ and 5 h after exercise, respectively, whereas no significant treatment differences were observed for TNF-α mRNA. CONCLUSIONS Beta2 -adrenergic stimulation with high doses of the selective beta2 -agonist salbutamol, preceeded by 4 consecutive daily doses, induces transcription of IL-6 in skeletal muscle in response to resistance exercise, and increases muscle IL-6 release in lean individuals.
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Affiliation(s)
- Morten Hostrup
- August Krogh Section of Human Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Jakob Grunnet Knudsen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Caroline Maag Kristensen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Søren Jessen
- August Krogh Section of Human Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Henriette Pilegaard
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Jens Bangsbo
- August Krogh Section of Human Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
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9
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Koike TE, Fuziwara CS, Brum PC, Kimura ET, Rando TA, Miyabara EH. Muscle Stem Cell Function Is Impaired in β2-Adrenoceptor Knockout Mice. Stem Cell Rev Rep 2022; 18:2431-2443. [PMID: 35244862 DOI: 10.1007/s12015-022-10334-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/15/2022] [Indexed: 11/30/2022]
Abstract
Knockout (ko) mice for the β2 adrenoceptor (Adrβ2) have impaired skeletal muscle regeneration, suggesting that this receptor is important for muscle stem cell (satellite cell) function. Here, we investigated the role of Adrβ2 in the function of satellite cells from β2ko mice in the context of muscle regeneration, through in vivo and in vitro experiments. Immunohistochemical analysis showed a significant reduction in the number of self-renewed Pax7+ satellite cells, proliferating Pax7+/MyoD+ myogenic precursor cells, and regenerating eMHC+ myofibers in regenerating muscle of β2ko mice at 30, 3, and 10 days post-injury, respectively. Quiescent satellite cells were isolated by fluorescence-activated cell sorting, and cell cycle entry was assessed by EdU incorporation. The results demonstrated a lower number of proliferating Pax7+/EdU+ satellite cells from β2ko mice. There was an increase in the gene expression of the cell cycle inhibitor Cdkn1a and Notch pathway components and the activation of Notch signaling in proliferating myoblasts from β2ko mice. There was a decrease in the number of myogenin-positive nuclei in myofibers maintained in differentiation media, and a lower fusion index in differentiating myoblasts from β2ko mice. Furthermore, the gene expression of Wnt/β-catenin signaling components, the expression of nuclear β-catenin and the activation of Wnt/β-catenin signaling decreased in differentiating myoblasts from β2ko mice. These results indicate that Adrβ2 plays a crucial role in satellite cell self-renewal, as well as in myoblast proliferation and differentiation by regulating Notch and Wnt/β-catenin signaling, respectively.
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Affiliation(s)
- Tatiana E Koike
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, Avenida Professor Lineu Prestes, 2415. CEP, São Paulo, SP, 05508-000, Brazil
| | - Cesar S Fuziwara
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Patricia C Brum
- School of Physical Education and Sport, University of São Paulo, São Paulo, SP, Brazil
| | - Edna T Kimura
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Thomas A Rando
- Veterans Affairs Palo Alto Health Care System, 3801 Miranda Avenue, Palo Alto, CA, USA.,Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA.,Broad Stem Cell Research Center, University of California Los Angeles, Los Angeles, CA, USA
| | - Elen H Miyabara
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, Avenida Professor Lineu Prestes, 2415. CEP, São Paulo, SP, 05508-000, Brazil.
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10
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Jessen S, Baasch-Skytte T, Onslev J, Eibye K, Backer V, Bangsbo J, Hostrup M. Muscle hypertrophic effect of inhaled beta 2 -agonist is associated with augmented insulin-stimulated whole-body glucose disposal in young men. J Physiol 2022; 600:2345-2357. [PMID: 35218559 PMCID: PMC9310637 DOI: 10.1113/jp282421] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 02/15/2022] [Indexed: 11/13/2022] Open
Abstract
Abstract Rodent studies highlight enhancement of glucose tolerance and insulin sensitivity as potential clinically relevant effects of chronic beta2‐agonist treatment. However, the doses administered to rodents are not comparable with the therapeutic doses used for humans. Thus, we investigated the physiological effects of prolonged beta2‐agonist treatment at inhaled doses resembling those used in respiratory diseases on insulin‐stimulated whole‐body glucose disposal and putative mechanisms in skeletal muscle and adipose tissue of healthy men. Utilizing a randomized placebo‐controlled parallel‐group design, we assigned 21 healthy men to 4 weeks daily inhalation of terbutaline (TER; 4 mg × day−1, n = 13) or placebo (PLA, n = 8). Before and after treatments, we assessed subjects’ whole‐body insulin‐stimulated glucose disposal and body composition, and collected vastus lateralis muscle and abdominal adipose tissue biopsies. Glucose infusion rate increased by 27% (95% CI: 80 to 238 mg × min−1, P = 0.001) in TER, whereas no significant changes occurred in PLA (95% CI: −37 to 195 mg × min−1, P = 0.154). GLUT4 content in muscle or adipose tissue did not change, nor did hexokinase II content or markers of mitochondrial volume in muscle. Change in lean mass was associated with change in glucose infusion rate in TER (r = 0.59, P = 0.03). Beta2‐agonist treatment in close‐to‐therapeutic doses may augment whole‐body insulin‐stimulated glucose disposal in healthy young men and part of the change is likely to be explained by muscle hypertrophy. These findings highlight the therapeutic potential of beta2‐agonists for improving insulin sensitivity. Key points While studies in rodents have highlighted beta2‐agonists as a means to augment insulin sensitivity, these studies utilized beta2‐agonists at doses inapplicable to humans. Herein we show that a 4‐week treatment period with daily therapeutic inhalation of beta2‐agonist increases insulin‐stimulated whole‐body glucose disposal in young healthy lean men. This effect was associated with an increase of lean mass but not with changes in GLUT4 and hexokinase II or basal glycogen content in skeletal muscle nor GLUT4 content in abdominal adipose tissue. These findings suggest that the enhanced insulin‐stimulated whole‐body glucose disposal induced by a period of beta2‐agonist treatment in humans, at least in part, is attributed to muscle hypertrophy. Our observations extend findings in rodents and highlight the therapeutic potential of beta2‐agonists to enhance the capacity for glucose disposal and whole‐body insulin sensitivity, providing important knowledge with potential application in insulin resistance.
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Affiliation(s)
- Søren Jessen
- The August Krogh Section for Human Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark
| | - Thomas Baasch-Skytte
- The August Krogh Section for Human Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark
| | - Johan Onslev
- The August Krogh Section for Human Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark
| | - Kasper Eibye
- The August Krogh Section for Human Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark
| | - Vibeke Backer
- Department of Otorhinolaryngology, Head and Neck Surgery, and Audiology, Rigshospitalet, Copenhagen, Denmark.,Center for Physical Activity, Rigshospitalet, Copenhagen, Denmark
| | - Jens Bangsbo
- The August Krogh Section for Human Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark
| | - Morten Hostrup
- The August Krogh Section for Human Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark
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11
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Shimamoto S, Nakashima K, Nishikoba N, Kohrogi R, Ohtsuka A, Fujimura S, Ijiri D. Suppression of FoxO1 mRNA by β 2 -adrenoceptor-cAMP signaling through miR-374b-5p and miR-7a-1-3p in C2C12 myotubes. FEBS Open Bio 2022; 12:627-637. [PMID: 35038382 PMCID: PMC8886325 DOI: 10.1002/2211-5463.13368] [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: 11/08/2021] [Revised: 12/21/2021] [Accepted: 01/13/2022] [Indexed: 11/09/2022] Open
Abstract
β2 -Adrenoceptor (β2 -AR) signaling decreases the transcriptional activity of forkhead box O (FoxO), but the underlying mechanisms remain incompletely understood. Here, we investigated how β2 -AR signaling regulates the protein abundance of FoxO and its transcriptional activity in skeletal muscle. We observed that stimulation of β2 -AR with its selective agonist, clenbuterol, rapidly decreased FoxO1 mRNA expression, and this was accompanied by a decrease in either FoxO1 protein level or FoxO transcriptional activity. We subsequently observed that miR-374b-5p and miR-7a-1-3p were rapidly upregulated in response to β2 -AR stimulation. Transfection with mimics of either miRNA successfully decreased FoxO1 mRNA. Moreover, because β2 -AR stimulation increased cAMP concentration, pretreatment with an adenylyl cyclase inhibitor canceled out these effects of β2 -AR stimulation. These results suggest that β2 -AR stimulation results in rapid upregulation of miR-374b-5p and miR-7a-1-3p in myotubes, which in turn results in a decrease in FoxO1 mRNA expression via the β2 -AR-cAMP signaling pathway.
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Affiliation(s)
- Saki Shimamoto
- Department of Agricultural Sciences and Natural Resources, Kagoshima University, 1-21-24 Korimoto, Kagoshima, 890-0065, Japan.,The United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24 Korimoto, Kagoshima, 890-0065, Japan.,Graduate School of Science and Technology, Niigata University, 8050 Ikarashi 2-nocho, Niigata, 950-2181, Japan
| | - Kazuki Nakashima
- Division of Meat Animal and Poultry Research, Institute of Livestock and Grassland Science, NARO, Ikenodai, Tsukuba, 305-0901, Japan
| | - Nao Nishikoba
- Department of Agricultural Sciences and Natural Resources, Kagoshima University, 1-21-24 Korimoto, Kagoshima, 890-0065, Japan
| | - Rukana Kohrogi
- Department of Agricultural Sciences and Natural Resources, Kagoshima University, 1-21-24 Korimoto, Kagoshima, 890-0065, Japan
| | - Akira Ohtsuka
- Department of Agricultural Sciences and Natural Resources, Kagoshima University, 1-21-24 Korimoto, Kagoshima, 890-0065, Japan.,The United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24 Korimoto, Kagoshima, 890-0065, Japan
| | - Shinobu Fujimura
- Graduate School of Science and Technology, Niigata University, 8050 Ikarashi 2-nocho, Niigata, 950-2181, Japan
| | - Daichi Ijiri
- Department of Agricultural Sciences and Natural Resources, Kagoshima University, 1-21-24 Korimoto, Kagoshima, 890-0065, Japan.,The United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24 Korimoto, Kagoshima, 890-0065, Japan
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12
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Skagen C, Nyman TA, Peng XR, O'Mahony G, Kase ET, Rustan AC, Thoresen GH. Chronic treatment with terbutaline increases glucose and oleic acid oxidation and protein synthesis in cultured human myotubes. CURRENT RESEARCH IN PHARMACOLOGY AND DRUG DISCOVERY 2021; 2:100039. [PMID: 34909668 PMCID: PMC8663959 DOI: 10.1016/j.crphar.2021.100039] [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: 05/04/2021] [Revised: 05/28/2021] [Accepted: 06/02/2021] [Indexed: 12/04/2022] Open
Abstract
Objective In vivo studies have reported several beneficial metabolic effects of β-adrenergic receptor agonist administration in skeletal muscle, including increased glucose uptake, fatty acid metabolism, lipolysis and mitochondrial biogenesis. Although these effects have been widely studied in vivo, the in vitro data are limited to mouse and rat cell lines. Therefore, we sought to discover the effects of the β2-adrenergic receptor agonist terbutaline on metabolism and protein synthesis in human primary skeletal muscle cells. Methods Human cultured myotubes were exposed to terbutaline in various concentrations (0.01–30 μM) for 4 or 96 h. Thereafter uptake of [14C]deoxy-D-glucose, oxydation of [14C]glucose and [14C]oleic acid were measured. Incorporation of [14C]leucine, gene expression by qPCR and proteomics analyses by mass spectrometry by the STAGE-TIP method were performed after 96 h exposure to 1 and 10 μM of terbutaline. Results The results showed that 4 h treatment with terbutaline in concentrations up to 1 μM increased glucose uptake in human myotubes, but also decreased both glucose and oleic acid oxidation along with oleic acid uptake in concentrations of 10–30 μM. Moreover, administration of terbutaline for 96 h increased glucose uptake (in terbutaline concentrations up to 1 μM) and oxidation (1 μM), as well as oleic acid oxidation (0.1–30 μM), leucine incorporation into cellular protein (1–10 μM) and upregulated several pathways related to mitochondrial metabolism (1 μM). Data are available via ProteomeXchange with identifier PXD024063. Conclusion These results suggest that β2-adrenergic receptor have direct effects in human skeletal muscle affecting fuel metabolism and net protein synthesis, effects that might be favourable for both type 2 diabetes and muscle wasting disorders. The metabolic effects of terbutaline were studied in human primary myotubes. Acute treatment with terbutaline increased glucose uptake. Chronic treatment with terbutaline increased glucose and oleic acid oxidation. Chronic treatment with terbutaline increased protein synthesis. Proteomics analysis revealed an increase in mitochondrial proteins.
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Affiliation(s)
- Christine Skagen
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Norway
| | - Tuula A Nyman
- Department of Immunology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Norway
| | - Xiao-Rong Peng
- Bioscience Metabolism, Research and Early Development Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Gavin O'Mahony
- Medicinal Chemsitry, Research and Early Development Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Eili Tranheim Kase
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Norway
| | - Arild Chr Rustan
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Norway
| | - G Hege Thoresen
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Norway.,Department of Pharmacology, Institute of Clinical Medicine, University of Oslo, Norway
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13
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Dietary protein considerations for muscle protein synthesis and muscle mass preservation in older adults. Nutr Res Rev 2020; 34:147-157. [PMID: 32883378 DOI: 10.1017/s0954422420000219] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Amino acid bioavailability is critical for muscle protein synthesis (MPS) and preservation of skeletal muscle mass (SMM). Ageing is associated with reduced responsiveness of MPS to essential amino acids (EAA). Further, the older adult population experiences anabolic resistance, leading to increased frailty, functional decline and depleted muscle mass preservation, which facilitates the need for increased protein intake to increase their SMM. This review focuses on the role of proteins in muscle mass preservation and examines the contribution of EAA and protein intake patterns to MPS. Leucine is the most widely studied amino acid for its role as a potent stimulator of MPS, though due to inadequate data little is yet known about the role of other EAA. Reaching a conclusion on the best pattern of protein intake has proven difficult due to conflicting studies. A mixture of animal and plant proteins can contribute to increased MPS and potentially attenuate muscle wasting conditions; however, there is limited research on the biological impact of protein blends in older adults. While there is some evidence to suggest that liquid protein foods with higher than the RDA of protein may be the best strategy for achieving high MPS rates in older adults, clinical trials are warranted to confirm an association between food form and SMM preservation. Further research is warranted before adequate recommendations and strategies for optimising SMM in the elderly population can be proposed.
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14
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Hostrup M, Jacobson GA, Jessen S, Lemminger AK. Anabolic and lipolytic actions of beta
2
‐agonists in humans and antidoping challenges. Drug Test Anal 2020; 12:597-609. [DOI: 10.1002/dta.2728] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 10/29/2019] [Indexed: 12/13/2022]
Affiliation(s)
- Morten Hostrup
- Department of Nutrition, Exercise and Sports, Section of Integrative PhysiologyUniversity of Copenhagen Copenhagen Denmark
| | - Glenn A. Jacobson
- School of Pharmacy and Pharmacology, College of Health and MedicineUniversity of Tasmania Hobart Australia
| | - Søren Jessen
- Department of Nutrition, Exercise and Sports, Section of Integrative PhysiologyUniversity of Copenhagen Copenhagen Denmark
| | - Anders Krogh Lemminger
- Department of Nutrition, Exercise and Sports, Section of Integrative PhysiologyUniversity of Copenhagen Copenhagen Denmark
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15
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Gonçalves DA, Silveira WA, Manfredi LH, Graça FA, Armani A, Bertaggia E, O Neill BT, Lautherbach N, Machado J, Nogara L, Pereira MG, Arcidiacono D, Realdon S, Kahn CR, Sandri M, Kettelhut IC, Navegantes LCC. Insulin/IGF1 signalling mediates the effects of β 2 -adrenergic agonist on muscle proteostasis and growth. J Cachexia Sarcopenia Muscle 2019; 10:455-475. [PMID: 30932373 PMCID: PMC6463755 DOI: 10.1002/jcsm.12395] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 12/18/2018] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Stimulation of β2 -adrenoceptors can promote muscle hypertrophy and fibre type shift, and it can counteract atrophy and weakness. The underlying mechanisms remain elusive. METHODS Fed wild type (WT), 2-day fasted WT, muscle-specific insulin (INS) receptor (IR) knockout (M-IR-/- ), and MKR mice were studied with regard to acute effects of the β2 -agonist formoterol (FOR) on protein metabolism and signalling events. MKR mice express a dominant negative IGF1 receptor, which blocks both INS/IGF1 signalling. All received one injection of FOR (300 μg kg-1 subcutaneously) or saline. Skeletal muscles and serum samples were analysed from 30 to 240 min. For the study of chronic effects of FOR on muscle plasticity and function as well as intracellular signalling pathways, fed WT and MKR mice were treated with formoterol (300 μg kg-1 day-1 ) for 30 days. RESULTS In fed and fasted mice, one injection of FOR inhibited autophagosome formation (LC3-II content, 65%, P ≤ 0.05) that was paralleled by an increase in serum INS levels (4-fold to 25-fold, P ≤ 0.05) and the phosphorylation of Akt (4.4-fold to 6.5-fold, P ≤ 0.05) and ERK1/2 (50% to two-fold, P ≤ 0.05). This led to the suppression (40-70%, P ≤ 0.05) of the master regulators of atrophy, FoxOs, and the mRNA levels of their target genes. FOR enhanced (41%, P ≤ 0.05) protein synthesis only in fed condition and stimulated (4.4-fold to 35-fold, P ≤ 0.05) the prosynthetic Akt/mTOR/p70S6K pathway in both fed and fasted states. FOR effects on Akt signalling during fasting were blunted in both M-IR-/- and MKR mice. Inhibition of proteolysis markers by FOR was prevented only in MKR mice. Blockade of PI3K/Akt axis and mTORC1, but not ERK1/2, in fasted mice also suppressed the acute FOR effects on proteolysis and autophagy. Chronic stimulation of β2 -adrenoceptors in fed WT mice increased body (11%, P ≤ 0.05) and muscle (15%, P ≤ 0.05) growth and downregulated atrophy-related genes (30-40%, P ≤ 0.05), but these effects were abolished in MKR mice. Increases in muscle force caused by FOR (WT, 24%, P ≤ 0.05) were only partially impaired in MKR mice (12%, P ≤ 0.05), and FOR-induced slow-to-fast fibre type shift was not blocked at all in these animals. In MKR mice, FOR also restored the lower levels of muscle SDH activity to basal WT values and caused a marked reduction (57%, P ≤ 0.05) in the number of centrally nucleated fibers. CONCLUSIONS NS/IGF1 signalling is necessary for the anti-proteolytic and hypertrophic effects of in vivo β2 -adrenergic stimulation and appears to mediate FOR-induced enhancement of protein synthesis. INS/IGF1 signalling only partially contributes to gain in strength and does not mediate fibre type transition induced by FOR.
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Affiliation(s)
- Dawit A Gonçalves
- Department of Physiology, Ribeirão Preto Medical School/University of São Paulo, Ribeirão Preto, SP, Brazil.,Department of Biochemistry/Immunology, Ribeirão Preto Medical School/University of São Paulo, Ribeirão Preto, SP, Brazil.,Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Wilian A Silveira
- Department of Physiology, Ribeirão Preto Medical School/University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Leandro H Manfredi
- Department of Physiology, Ribeirão Preto Medical School/University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Flávia A Graça
- Department of Physiology, Ribeirão Preto Medical School/University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Andrea Armani
- Department of Biomedical Sciences, University of Padova, Padova, Italy.,Venetian Institute of Molecular Medicine, Padova, Italy
| | - Enrico Bertaggia
- Department of Biomedical Sciences, University of Padova, Padova, Italy.,Venetian Institute of Molecular Medicine, Padova, Italy
| | - Brian T O Neill
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA
| | - Natalia Lautherbach
- Department of Physiology, Ribeirão Preto Medical School/University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Juliano Machado
- Department of Physiology, Ribeirão Preto Medical School/University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Leonardo Nogara
- Department of Biomedical Sciences, University of Padova, Padova, Italy.,Venetian Institute of Molecular Medicine, Padova, Italy
| | - Marcelo G Pereira
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Diletta Arcidiacono
- Digestive Endoscopy Unit, Veneto Institute of Oncology IOV-IRCCS, Padova, Italy
| | - Stefano Realdon
- Digestive Endoscopy Unit, Veneto Institute of Oncology IOV-IRCCS, Padova, Italy
| | - C Ronald Kahn
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA
| | - Marco Sandri
- Department of Biomedical Sciences, University of Padova, Padova, Italy.,Venetian Institute of Molecular Medicine, Padova, Italy.,Myology Center, University of Padova, Padova, Italy
| | - Isis C Kettelhut
- Department of Physiology, Ribeirão Preto Medical School/University of São Paulo, Ribeirão Preto, SP, Brazil.,Department of Biochemistry/Immunology, Ribeirão Preto Medical School/University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Luiz Carlos C Navegantes
- Department of Physiology, Ribeirão Preto Medical School/University of São Paulo, Ribeirão Preto, SP, Brazil
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16
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High altitude mediated skeletal muscle atrophy: Protective role of curcumin. Biochimie 2019; 156:138-147. [DOI: 10.1016/j.biochi.2018.10.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 10/16/2018] [Indexed: 12/21/2022]
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17
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Lynch GS, Koopman R. Overcoming nature’s paradox in skeletal muscle to optimise animal production. ANIMAL PRODUCTION SCIENCE 2019. [DOI: 10.1071/an19361] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Nature’s paradox in skeletal muscle describes the seemingly mutually exclusive relationship between muscle fibre size and oxidative capacity. In mammals, there is a constraint on the size at which mitochondria-rich, high O2-dependent oxidative fibres can attain before they become anoxic or adapt to a glycolytic phenotype, being less reliant on O2. This implies that a muscle fibre can hypertrophy at the expense of its endurance capacity. Adaptations to activity (exercise) generally obey this relationship, with optimal muscle endurance generally being linked to an enhanced proportion of small, slow oxidative fibres and muscle strength (force and/or power) being linked to an enhanced proportion of large, fast glycolytic fibres. This relationship generally constrains not only the physiological limits of performance (e.g. speed and endurance), but also the capacity to manipulate muscle attributes such as fibre size and composition, with important relevance to the livestock and aquaculture industries for producing specific muscle traits such as (flesh) quality, texture and taste. Highly glycolytic (white) muscles have different traits than do highly oxidative (red) muscles and so the ability to manipulate muscle attributes to produce flesh with specific traits has important implications for optimising meat production and quality. Understanding the biological regulation of muscle size, and phenotype and the capacity to manipulate signalling pathways to produce specific attributes, has important implications for promoting ethically sustainable and profitable commercial livestock and aquaculture practices and for developing alternative food sources, including ‘laboratory meat’ or ‘clean meat’. This review describes the exciting potential of manipulating muscle attributes relevant to animal production, through traditional nutritional and pharmacological approaches and through viral-mediated strategies that could theoretically push the limits of muscle fibre growth, adaptation and plasticity.
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18
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The Beta-adrenergic agonist, Ractopamine, increases skeletal muscle expression of Asparagine Synthetase as part of an integrated stress response gene program. Sci Rep 2018; 8:15915. [PMID: 30374102 PMCID: PMC6206132 DOI: 10.1038/s41598-018-34315-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 10/15/2018] [Indexed: 12/31/2022] Open
Abstract
Synthetic beta-adrenergic agonists (BA) have broad biomedical and agricultural application for increasing lean body mass, yet a poor understanding of the biology underpinning these agents is limiting further drug discovery potential. Growing female pigs (77 ± 7 kg) were administered the BA, Ractopamine (20 ppm in feed), or the recombinant growth hormone (GH), Reporcin (10 mg/48 hrs injected) for 1, 3, 7, 13 (n = 10 per treatment, per time point) or 27 days (n = 15 per treatment). Using RNA-sequencing and inferred pathway analysis, we examined temporal changes to the Longissimus Dorsi skeletal muscle transcriptome (n = 3 per treatment, per time point) relative to a feed-only control cohort. Gene expression changes were affirmed by quantitative-PCR on all samples (n = 164). RNA-sequencing analysis revealed that BA treatment had greater effects than GH, and that asparagine synthetase (Asns) was the 5th most significantly increased gene by BA at day 3. ASNS protein expression was dramatically increased by BA treatment at day 7 (p < 0.05). The most significantly increased gene at day 3 was activating transcription factor 5 (Atf5), a transcription factor known to regulate ASNS gene expression. Gene and protein expression of Atf4, another known regulator of Asns expression, was not changed by BA treatment. Expression of more than 20 known Atf4 target genes were increased by BA treatment, suggesting that BA treatment induces an integrated stress response (ISR) in skeletal muscle of pigs. In support of this, mRNA expression of sestrin-2 (Sesn2) and cyclin-dependant kinase 1 alpha (Cdkn1a), two key stress-responsive genes and negative regulators of cellular growth, were also strongly increased from day 3 of BA treatment. Finally, tRNA charging was the most significantly enriched pathway induced by BA treatment, suggesting alterations to the translational capacity/efficiency of the muscle. BA-mediated changes to the skeletal muscle transcriptome are highly indicative of an integrated stress response (ISR), particularly genes relating to amino acid biosynthesis and protein translational capacity.
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19
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Chikazawa M, Sato R. Identification of a Novel Function of Resveratrol and Genistein as a Regulator of β 2 -Adrenergic Receptor Expression in Skeletal Muscle Cells and Characterization of Promoter Elements Required for Promoter Activation. Mol Nutr Food Res 2018; 62:e1800530. [PMID: 30184338 DOI: 10.1002/mnfr.201800530] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 08/22/2018] [Indexed: 11/09/2022]
Abstract
SCOPE Modulating β2 -adrenergic receptor (β2 -AR) expression and activation is important for maintaining skeletal muscle function. In this study, two food factors, resveratrol (RSV) and genistein (GEN), that are able to regulate β2 -AR promoter activity and may improve skeletal muscle function are identified. METHODS AND RESULTS Using luciferase reporter assay, 357 functional food factors as candidates for β2 -AR promoter activity have been screened and subsequently RSV and GEN increase β2 -AR promoter activity and β2 -AR mRNA expression. Using promoter sequence analysis, it is shown that the CCAAT box and the GC box on the β2 -AR promoter are required for the regulation of β2 -AR expression by RSV or GEN. It is also ascertained that transcription factor NF-YA binds to the CCAAT box on the β2 -AR promoter and that the amount of NF-YA bound to the CCAAT box is unchanged by RSV or GEN treatment. Finally, it is confirmed that a GEN-containing diet increases β2 -AR expression in mouse skeletal muscle and increased skeletal muscle mass. CONCLUSIONS The findings show that food-derived molecules have the potential to influence skeletal muscle mass and function by regulating G protein-coupled receptor expression.
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Affiliation(s)
- Miho Chikazawa
- Food Biochemistry Laboratory, Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Ryuichiro Sato
- Food Biochemistry Laboratory, Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.,Nutri-Life Science Laboratory, Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.,AMED-CREST, Japan Agency for Medical Research and Development, Chiyoda-ku, Tokyo, Japan
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20
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Hostrup M, Reitelseder S, Jessen S, Kalsen A, Nyberg M, Egelund J, Kreiberg M, Kristensen CM, Thomassen M, Pilegaard H, Backer V, Jacobson GA, Holm L, Bangsbo J. Beta 2 -adrenoceptor agonist salbutamol increases protein turnover rates and alters signalling in skeletal muscle after resistance exercise in young men. J Physiol 2018; 596:4121-4139. [PMID: 29968301 DOI: 10.1113/jp275560] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 06/29/2018] [Indexed: 01/08/2023] Open
Abstract
KEY POINTS Animal models have shown that beta2 -adrenoceptor stimulation increases protein synthesis and attenuates breakdown processes in skeletal muscle. Thus, the beta2 -adrenoceptor is a potential target in the treatment of disuse-, disease- and age-related muscle atrophy. In the present study, we show that a few days of oral treatment with the commonly prescribed beta2 -adrenoceptor agonist, salbutamol, increased skeletal muscle protein synthesis and breakdown during the first 5 h after resistance exercise in young men. Salbutamol also counteracted a negative net protein balance in skeletal muscle after resistance exercise. Changes in protein turnover rates induced by salbutamol were associated with protein kinase A-signalling, activation of Akt2 and modulation of mRNA levels of growth-regulating proteins in skeletal muscle. These findings indicate that protein turnover rates can be augmented by beta2 -adrenoceptor agonist treatment during recovery from resistance exercise in humans. ABSTRACT The effect of beta2 -adrenoceptor stimulation on skeletal muscle protein turnover and intracellular signalling is insufficiently explored in humans, particularly in association with exercise. In a randomized, placebo-controlled, cross-over study investigating 12 trained men, the effects of beta2 -agonist (6 × 4 mg oral salbutamol) on protein turnover rates, intracellular signalling and mRNA response in skeletal muscle were investigated 0.5-5 h after quadriceps resistance exercise. Each trial was preceded by a 4-day lead-in treatment period. Leg protein turnover rates were assessed by infusion of [13 C6 ]-phenylalanine and sampling of arterial and venous blood, as well as vastus lateralis muscle biopsies 0.5 and 5 h after exercise. Furthermore, myofibrillar fractional synthesis rate, intracellular signalling and mRNA response were measured in muscle biopsies. The mean (95% confidence interval) myofibrillar fractional synthesis rate was higher for salbutamol than placebo [0.079 (95% CI, 0.064 to 0.093) vs. 0.066 (95% CI, 0.056 to 0.075%) × h-1 ] (P < 0.05). Mean net leg phenylalanine balance 0.5-5 h after exercise was higher for salbutamol than placebo [3.6 (95% CI, 1.0 to 6.2 nmol) × min-1 × 100 gLeg Lean Mass-1 ] (P < 0.01). Phosphorylation of Akt2, cAMP response element binding protein and PKA substrate 0.5 and 5 h after exercise, as well as phosphorylation of eEF2 5 h after exercise, was higher (P < 0.05) for salbutamol than placebo. Calpain-1, Forkhead box protein O1, myostatin and Smad3 mRNA content was higher (P < 0.01) for salbutamol than placebo 0.5 h after exercise, as well as Forkhead box protein O1 and myostatin mRNA content 5 h after exercise, whereas ActivinRIIB mRNA content was lower (P < 0.01) for salbutamol 5 h after exercise. These observations suggest that beta2 -agonist increases protein turnover rates in skeletal muscle after resistance exercise in humans, with concomitant cAMP/PKA and Akt2 signalling, as well as modulation of mRNA response of growth-regulating proteins.
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Affiliation(s)
- Morten Hostrup
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark.,Department of Respiratory Medicine, Bispebjerg University Hospital, Copenhagen, Denmark
| | - Søren Reitelseder
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery M, Bispebjerg University Hospital, Copenhagen, Denmark
| | - Søren Jessen
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark.,Department of Respiratory Medicine, Bispebjerg University Hospital, Copenhagen, Denmark
| | - Anders Kalsen
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark.,Department of Respiratory Medicine, Bispebjerg University Hospital, Copenhagen, Denmark
| | - Michael Nyberg
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Jon Egelund
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Michael Kreiberg
- Department of Respiratory Medicine, Bispebjerg University Hospital, Copenhagen, Denmark
| | | | - Martin Thomassen
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Henriette Pilegaard
- Department of Biology, University of Copenhagen, Copenhagen, Copenhagen, Denmark
| | - Vibeke Backer
- Department of Respiratory Medicine, Bispebjerg University Hospital, Copenhagen, Denmark
| | - Glenn A Jacobson
- Division of Pharmacy, School of Medicine, University of Tasmania, Hobart, Australia
| | - Lars Holm
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery M, Bispebjerg University Hospital, Copenhagen, Denmark.,Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,School of Sport Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - Jens Bangsbo
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
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21
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Xie Y, Perry BD, Espinoza D, Zhang P, Price SR. Glucocorticoid-induced CREB activation and myostatin expression in C2C12 myotubes involves phosphodiesterase-3/4 signaling. Biochem Biophys Res Commun 2018; 503:1409-1414. [PMID: 30025893 PMCID: PMC6173943 DOI: 10.1016/j.bbrc.2018.07.056] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Accepted: 07/10/2018] [Indexed: 11/02/2022]
Abstract
Muscle atrophy in metabolic conditions like chronic kidney disease (CKD) and diabetes are associated with glucocorticoid production, dysfunctional insulin/Akt/FoxO3 signaling and increased myostatin expression. We recently found that CREB, a transcription factor proposed to regulate myostatin expression, is highly phosphorylated in some wasting conditions. Based on a novel Akt-PDE3/4 signaling paradigm, we hypothesized that reduced Akt signaling contributes to CREB activation and myostatin expression. C2C12 myotubes were incubated with dexamethasone (Dex), an atrophy-inducing synthetic glucocorticoid. Akt/CREB signaling and myostatin expression were evaluated by immunoblot and qPCR analyses. Inhibitors of Akt, phosphodiesterase (PDE)-3/4, and protein kinase A (PKA) signaling were used to test our hypothesis. Incubating myotubes with Dex for 3-24 h inhibited Akt phosphorylation and enhanced CREB phosphorylation as well as myostatin mRNA and protein. Inhibition of PI3K/Akt signaling with LY294002 similarly increased CREB phosphorylation. Isobutyl-methylxanthine (IBMX, a pan PDE inhibitor), milrinone (PDE3 inhibitor) and rolipram (PDE4 inhibitor) augmented CREB phosphorylation and myostatin expression. Inhibition of protein kinase A by PKI reverted Dex- or IBMX-induced CREB phosphorylation and myostatin expression. Our study provides evidence supporting a newly identified mechanism by which a glucocorticoid-related reduction in Akt signaling contributes to myostatin expression via CREB activation.
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Affiliation(s)
- Yang Xie
- Department of Medicine, Renal Division, Emory University, Atlanta, GA 30322, USA; Department of Nephrology, Xiangya Hospital and Xiangya School of Medicine, Central South University, Changsha, Hunan 410008, PR China; Department of Nephrology, Beijing Hospital, Beijing 100730, PR China
| | - Ben D Perry
- Department of Medicine, Renal Division, Emory University, Atlanta, GA 30322, USA; Research Service Line, Atlanta Veterans Affairs Medical Center, Decatur, GA 30033, USA; School of Science and Health, Western Sydney University, Campbelltown NSW 2560, Australia
| | - Daniel Espinoza
- Research Service Line, Atlanta Veterans Affairs Medical Center, Decatur, GA 30033, USA
| | - Peng Zhang
- Department of Medicine, Renal Division, Emory University, Atlanta, GA 30322, USA; Research Service Line, Atlanta Veterans Affairs Medical Center, Decatur, GA 30033, USA
| | - S Russ Price
- Department of Medicine, Renal Division, Emory University, Atlanta, GA 30322, USA; Research Service Line, Atlanta Veterans Affairs Medical Center, Decatur, GA 30033, USA; Department of Biochemistry and Molecular Biology, Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA.
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22
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Xia Z, Cholewa JM, Zhao Y, Yang Y, Shang H, Jiang H, Su Q, Zanchi NE. A potential strategy for counteracting age-related sarcopenia: preliminary evidence of combined exercise training and leucine supplementation. Food Funct 2018; 8:4528-4538. [PMID: 29099523 DOI: 10.1039/c7fo01181d] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Previous research has demonstrated the positive effects of concurrent/combined aerobic and resistance exercise or leucine supplementation on skeletal muscle protein synthesis (MPS) and hypertrophy in aging organisms. However, the effects of a multimodal intervention which combines both aerobic and resistance exercise and leucine supplementation has not been fully elucidated. Eighteen month old and 2 month old C57BL/6 mice were assigned to aging control (AC, n = 8), aging and multimodal intervention (AMI, n = 8) and young control (YC, n = 8). Mice in the YC and AC groups were fed an alanine-rich diet (3.4%), and mice in the AMI group received an isonitrogenous leucine-supplemented (5%) diet in combination with combined aerobic (30 minutes swimming) and resistance exercise training (incremental jumping submersed in water with overload corresponding to 40%-50% body weight) for a total of 4 weeks. The gastrocnemius muscles were dissected for western blotting detection (signaling proteins involved in MPS) and the ex vivo determination of protein synthesis and protein content. The muscle strength of the hind limbs was measured pre-experiment and repeated once per week on Sunday for 4 weeks. Mice in the AC and AMI groups showed lower ex vivo protein synthesis, protein content, expression of signaling proteins involved in MPS, maximal grip strength but higher plasma cortisol compared with the YC group post intervention. When compared to AC mice, the multimodal treatment led to lower activity of Sestrin2, higher expression of PI3K III and the phosphorylation of mTOR, p70S6K and 4E-BP1, as well as higher plasma leucine, wet gastrocnemius muscle weight and muscle weight to body weight ratio. Furthermore, the multimodal intervention induced more pronounced anabolic response such as higher ex vivo protein synthesis rate, total protein content, and myofibrillar fractions in gastrocnemius muscle, and greater maximum grip strength. The present research shows that a multimodal intervention including combined both aerobic and resistance exercise training and 5% leucine supplementation has the potential to maintain skeletal muscle protein synthesis and attenuate losses in muscular strength during the aging process.
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Affiliation(s)
- Z Xia
- Exercise Physiology and Biochemistry Laboratory, College of Physical Education, Jinggangshan University, Ji'an, China
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23
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Abstract
The World Anti-Doping Agency (WADA) currently allows therapeutic use of the beta2-agonists salbutamol, formoterol and salmeterol when delivered via inhalation despite some evidence suggesting these anti-asthma drugs may be performance enhancing. Beta2-agonists are usually administered as 50:50 racemic mixtures of two enantiomers (non-superimposable mirror images), one of which demonstrates significant beta2-adrenoceptor-mediated bronchodilation while the other appears to have little or no pharmacological activity. For salbutamol and formoterol, urine thresholds have been adopted to limit supratherapeutic dosing and to discriminate between inhaled (permitted) and oral (prohibited) use. However, chiral switches have led to the availability of enantiopure (active enantiomer only) preparations of salbutamol and formoterol, which effectively doubles their urine thresholds and provides a means for athletes to take supratherapeutic doses for doping purposes. Given the availability of these enantiopure beta2-agonists, the analysis of these drugs using enantioselective assays should now become routine. For salmeterol, there is currently only a therapeutic dose threshold and adoption of a urinary threshold should be a high priority for doping control.
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24
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Hostrup M, Onslev J, Jacobson GA, Wilson R, Bangsbo J. Chronic β 2 -adrenoceptor agonist treatment alters muscle proteome and functional adaptations induced by high intensity training in young men. J Physiol 2017; 596:231-252. [PMID: 28983994 DOI: 10.1113/jp274970] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 09/26/2017] [Indexed: 12/26/2022] Open
Abstract
KEY POINTS While several studies have investigated the effects of exercise training in human skeletal muscle and the chronic effect of β2 -agonist treatment in rodent muscle, their effects on muscle proteome signature with related functional measures in humans are still incompletely understood. Herein we show that daily β2 -agonist treatment attenuates training-induced enhancements in exercise performance and maximal oxygen consumption, and alters muscle proteome signature and phenotype in trained young men. Daily β2 -agonist treatment abolished several of the training-induced enhancements in muscle oxidative capacity and caused a repression of muscle metabolic pathways; furthermore, β2 -agonist treatment induced a slow-to-fast twitch muscle phenotype transition. The present study indicates that chronic β2 -agonist treatment confounds the positive effect of high intensity training on exercise performance and oxidative capacity, which is of interest for the large proportion of persons using inhaled β2 -agonists on a daily basis, including athletes. ABSTRACT Although the effects of training have been studied for decades, data on muscle proteome signature remodelling induced by high intensity training in relation to functional changes in humans remains incomplete. Likewise, β2 -agonists are frequently used to counteract exercise-induced bronchoconstriction, but the effects β2 -agonist treatment on muscle remodelling and adaptations to training are unknown. In a placebo-controlled parallel study, we randomly assigned 21 trained men to 4 weeks of high intensity training with (HIT+β2 A) or without (HIT) daily inhalation of β2 -agonist (terbutaline, 4 mg dose-1 ). Of 486 proteins identified by mass-spectrometry proteomics of muscle biopsies sampled before and after the intervention, 32 and 85 were changing (false discovery rate (FDR) ≤5%) with the intervention in HIT and HIT+β2 A, respectively. Proteome signature changes were different in HIT and HIT+β2 A (P = 0.005), wherein β2 -agonist caused a repression of 25 proteins in HIT+β2 A compared to HIT, and an upregulation of 7 proteins compared to HIT. β2 -Agonist repressed or even downregulated training-induced enrichment of pathways related to oxidative phosphorylation and glycogen metabolism, but upregulated pathways related to histone trimethylation and the nucleosome. Muscle contractile phenotype changed differently in HIT and HIT+β2 A (P ≤ 0.001), with a fast-to-slow twitch transition in HIT and a slow-to-fast twitch transition in HIT+β2 A. β2 -Agonist attenuated training-induced enhancements in maximal oxygen consumption (P ≤ 0.01) and exercise performance (6.1 vs. 11.6%, P ≤ 0.05) in HIT+β2 A compared to HIT. These findings indicate that daily β2 -agonist treatment attenuates the beneficial effects of high intensity training on exercise performance and oxidative capacity, and causes remodelling of muscle proteome signature towards a fast-twitch phenotype.
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Affiliation(s)
- Morten Hostrup
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Johan Onslev
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Glenn A Jacobson
- Division of Pharmacy, School of Medicine, University of Tasmania, Hobart, Australia
| | - Richard Wilson
- Central Science Laboratory, University of Tasmania, Hobart, Australia
| | - Jens Bangsbo
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
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25
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Forkuo GS, Kim H, Thanawala VJ, Al-Sawalha N, Valdez D, Joshi R, Parra S, Pera T, Gonnella PA, Knoll BJ, Walker JKL, Penn RB, Bond RA. Phosphodiesterase 4 Inhibitors Attenuate the Asthma Phenotype Produced by β2-Adrenoceptor Agonists in Phenylethanolamine N-Methyltransferase-Knockout Mice. Am J Respir Cell Mol Biol 2017; 55:234-42. [PMID: 26909542 DOI: 10.1165/rcmb.2015-0373oc] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Mice lacking the endogenous β2-adrenoceptor (β2AR) agonist epinephrine (phenylethanolamine N-methyltransferase [PNMT]-knockout mice) are resistant to developing an "asthma-like" phenotype in an ovalbumin sensitization and challenge (Ova S/C) model, and chronic administration of β2AR agonists to PNMT-KO mice restores the phenotype. Based on these and other studies showing differential effects of various β2AR ligands on the asthma phenotype, we have speculated that the permissive effect of endogenous epinephrine and exogenous β2AR agonists on allergic lung inflammation can be explained by qualitative β2AR signaling. The β2AR can signal through at least two pathways: the canonical Gαs-cAMP pathway and a β-arrestin-dependent pathway. Previous studies suggest that β-arrestin-2 is required for allergic lung inflammation. On the other hand, cell-based assays suggest antiinflammatory effects of Gαs-cAMP signaling. This study was designed to test whether the in vitro antiinflammatory effects of phosphodiesterase 4 inhibitors, known to increase intracellular cAMP in multiple airway cell types, attenuate the asthma-like phenotype produced by the β2AR agonists formoterol and salmeterol in vivo in PNMT-KO mice, based on the hypothesis that skewing β2AR signaling toward Gαs-cAMP pathway is beneficial. Airway inflammatory cells, epithelial mucus production, and airway hyperresponsiveness were quantified. In Ova S/C PNMT-KO mice, formoterol and salmeterol restored the asthma-like phenotype comparable to Ova S/C wild-type mice. However, coadministration of either roflumilast or rolipram attenuated this formoterol- or salmeterol-driven phenotype in Ova S/C PNMT-KO. These findings suggest that amplification of β2AR-mediated cAMP by phosphodiesterase 4 inhibitors attenuates the asthma-like phenotype promoted by β-agonists.
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Affiliation(s)
- Gloria S Forkuo
- 1 Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Houston, Texas
| | - Hosu Kim
- 1 Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Houston, Texas
| | - Vaidehi J Thanawala
- 1 Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Houston, Texas
| | - Nour Al-Sawalha
- 1 Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Houston, Texas
| | - Daniel Valdez
- 2 Department of Biology and Biochemistry, University of Houston, Houston, Texas
| | - Radhika Joshi
- 1 Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Houston, Texas
| | | | - Tonio Pera
- 4 Center for Translational Medicine and Jane and Leonard Korman Lung Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania; and
| | - Patricia A Gonnella
- 4 Center for Translational Medicine and Jane and Leonard Korman Lung Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania; and
| | - Brian J Knoll
- 1 Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Houston, Texas.,2 Department of Biology and Biochemistry, University of Houston, Houston, Texas
| | - Julia K L Walker
- 5 Duke University School of Nursing, Duke University Medical Center, Durham, North Carolina
| | - Raymond B Penn
- 4 Center for Translational Medicine and Jane and Leonard Korman Lung Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania; and
| | - Richard A Bond
- 1 Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Houston, Texas.,2 Department of Biology and Biochemistry, University of Houston, Houston, Texas
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26
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Shimamoto S, Ijiri D, Kawaguchi M, Nakashima K, Tada O, Inoue H, Ohtsuka A. β 1- and β 2-adrenergic receptor stimulation differ in their effects on PGC-1α and atrogin-1/MAFbx gene expression in chick skeletal muscle. Comp Biochem Physiol A Mol Integr Physiol 2017; 211:1-6. [PMID: 28578076 DOI: 10.1016/j.cbpa.2017.05.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 05/24/2017] [Accepted: 05/26/2017] [Indexed: 11/18/2022]
Abstract
Adrenaline changes expression of the genes encoding peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PGC-1α), which is known as a regulator of muscle size, and atrogin-1/muscle atrophy F-box (MAFbx), which is a muscle-specific ubiquitin ligase. However, the subtype of β-adrenergic receptor (β-AR) involved in regulating these genes in skeletal muscle is not yet well defined. In this study, the effects of intraperitoneal injection of adrenaline and three β1-3-AR selective agonists on chick skeletal muscle metabolism were examined, to evaluate the functions of β-AR subtypes. Adrenaline decreased atrogin-1/MAFbx mRNA levels accompanied by an increase in PGC-1α mRNA and protein levels. However, among the three selective agonists, only the β1-AR agonist, dobutamine, increased PGC-1α mRNA and protein levels, while the β2-AR agonist, clenbuterol, suppressed atrogin-1/MAFbx mRNA levels. In addition, preinjection of the β1-AR antagonist, acebutolol, and the β2-AR antagonist, butoxamine, inhibited the adrenaline-induced increase in PGC-1α mRNA levels and the decrease in atrogin-1/MAFbx mRNA levels, respectively. Compared with adrenaline administration, the β3-AR agonist, BRL37344, decreased PGC-1α mRNA levels and increased atrogin-1/MAFbx mRNA levels. These results suggest that, in chick skeletal muscle, PGC-1α is induced via the β1-AR, while atrogin-1/MAFbx is suppressed via the β2-AR.
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Affiliation(s)
- Saki Shimamoto
- Department of Biochemical Science and Technology, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan; The United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
| | - Daichi Ijiri
- Department of Biochemical Science and Technology, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan.
| | - Mana Kawaguchi
- Department of Biochemical Science and Technology, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
| | - Kazuki Nakashima
- Division of Animal Metabolism and Nutrition, Institute of Livestock and Grassland Science, NARO, 2 Ikenodai, Tsukuba 305-0901, Japan
| | - Osamu Tada
- Department of Life and Environmental Science, Kagoshima Prefectural College, 1-52-1 Shimoishiki, Kagoshima 890-0005, Japan
| | - Hiroki Inoue
- Department of Biochemical Science and Technology, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
| | - Akira Ohtsuka
- Department of Biochemical Science and Technology, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
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27
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Manfredi LH, Lustrino D, Machado J, Silveira WA, Zanon NM, Navegantes LC, Kettelhut IC. Adrenodemedullation activates the Ca2+-dependent proteolysis in soleus muscles from rats exposed to cold. J Appl Physiol (1985) 2017; 122:317-326. [DOI: 10.1152/japplphysiol.00198.2016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 09/20/2016] [Accepted: 10/04/2016] [Indexed: 01/19/2023] Open
Abstract
Previous studies have shown that catecholamines in vivo and in vitro inhibit the activity of Ca2+-dependent proteolysis in skeletal muscles under basal conditions. In the present study we sought to investigate the role of catecholamines in regulating the Ca2+-dependent proteolysis in soleus and extensor digitorum longus (EDL) muscles from rats acutely exposed to cold. Overall proteolysis, the activity of proteolytic systems, protein levels and gene expression of different components of the calpain system were investigated in rats submitted to adrenodemedullation (ADMX) and exposed to cold for 24 h. ADMX drastically reduced plasma epinephrine and promoted an additional increase in the overall proteolysis, which was already increased by cold exposure. The rise in the rate of protein degradation in soleus muscles from adrenodemedullated cold-exposed rats was caused by the high activity of the Ca2+-dependent proteolysis, which was associated with the generation of a 145-kDa cleaved α-fodrin fragment, a typical calpain substrate, and lower protein levels and mRNA expression of calpastatin, the endogenous calpain inhibitor. Unlike that observed for soleus muscles, the cold-induced muscle proteolysis in EDL was not affected by ADMX. In isolated soleus muscle, clenbuterol, a selective β2-adrenoceptor agonist, reduced the basal Ca2+-dependent proteolysis and completely abolished the activation of this pathway by the cholinergic agonist carbachol. These data suggest that catecholamines released from the adrenal medulla inhibit cold-induced protein breakdown in soleus, and this antiproteolytic effect on the Ca2+-dependent proteolytic system is apparently mediated through expression of calpastatin, which leads to suppression of calpain activation. NEW & NOTEWORTHY Although many effects of the sympathetic nervous system on muscle physiology are known, the role of catecholamines in skeletal muscle protein metabolism has been scarcely studied. We suggest that catecholamines released from adrenal medulla may be of particular importance for restraining the activation of the Ca2+-dependent proteolysis in soleus muscles during acute cold exposure. This finding helps us to understand the adaptive changes that occur in skeletal muscle protein metabolism during cold stress.
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Affiliation(s)
- L. H. Manfredi
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
- Federal University of Fronteira Sul (UFFS), Chapecó, Santa Catarina, Brazil; and
| | - D. Lustrino
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
- Department of Physiology, Federal University of Sergipe, São Cristóvão, Sergipe, Brazil
| | - J. Machado
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - W. A. Silveira
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - N. M. Zanon
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - L. C. Navegantes
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - I. C. Kettelhut
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
- Department of Biochemistry/Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
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28
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Fujikawa T, Castorena CM, Pearson M, Kusminski CM, Ahmed N, Battiprolu PK, Kim KW, Lee S, Hill JA, Scherer PE, Holland WL, Elmquist JK. SF-1 expression in the hypothalamus is required for beneficial metabolic effects of exercise. eLife 2016; 5. [PMID: 27874828 PMCID: PMC5119890 DOI: 10.7554/elife.18206] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 11/14/2016] [Indexed: 12/31/2022] Open
Abstract
Exercise has numerous beneficial metabolic effects. The central nervous system (CNS) is critical for regulating energy balance and coordinating whole body metabolism. However, a role for the CNS in the regulation of metabolism in the context of the exercise remains less clear. Here, using genetically engineered mice we assessed the requirement of steroidogenic factor-1 (SF-1) expression in neurons of the ventromedial hypothalamic nucleus (VMH) in mediating the beneficial effects of exercise on metabolism. We found that VMH-specific deletion of SF-1 blunts (a) the reductions in fat mass, (b) improvements in glycemia, and (c) increases in energy expenditure that are associated with exercise training. Unexpectedly, we found that SF-1 deletion in the VMH attenuates metabolic responses of skeletal muscle to exercise, including induction of PGC-1α expression. Collectively, this evidence suggests that SF-1 expression in VMH neurons is required for the beneficial effects of exercise on metabolism.
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Affiliation(s)
- Teppei Fujikawa
- Department of Internal Medicine, Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, United States
| | - Carlos M Castorena
- Department of Internal Medicine, Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, United States
| | - Mackenzie Pearson
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, United States
| | - Christine M Kusminski
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, United States
| | - Newaz Ahmed
- Department of Internal Medicine, Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, United States
| | - Pavan K Battiprolu
- Department of Internal Medicine, Division of Cardiology, University of Texas Southwestern Medical Center, Dallas, United States
| | - Ki Woo Kim
- Department of Pharmacology, Wonju College of Medicine, Yonsei University, Wonju, South Korea.,Department of Global Medical Science, Wonju College of Medicine, Yonsei University, Wonju, South Korea.,Institute of Lifestyle Medicine and Nuclear Receptor Research Consortium, Wonju College of Medicine, Yonsei University, Wonju, South Korea
| | - Syann Lee
- Department of Internal Medicine, Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, United States
| | - Joseph A Hill
- Department of Internal Medicine, Division of Cardiology, University of Texas Southwestern Medical Center, Dallas, United States.,Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, United States
| | - Philipp E Scherer
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, United States.,Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, United States
| | - William L Holland
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, United States
| | - Joel K Elmquist
- Department of Internal Medicine, Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, United States.,Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, United States
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29
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Puzzo D, Raiteri R, Castaldo C, Capasso R, Pagano E, Tedesco M, Gulisano W, Drozd L, Lippiello P, Palmeri A, Scotto P, Miniaci MC. CL316,243, a β3-adrenergic receptor agonist, induces muscle hypertrophy and increased strength. Sci Rep 2016; 5:37504. [PMID: 27874066 PMCID: PMC5118701 DOI: 10.1038/srep37504] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 10/28/2016] [Indexed: 12/12/2022] Open
Abstract
Studies in vitro have demonstrated that β3-adrenergic receptors (β3-ARs) regulate protein metabolism in skeletal muscle by promoting protein synthesis and inhibiting protein degradation. In this study, we evaluated whether activation of β3-ARs by the selective agonist CL316,243 modifies the functional and structural properties of skeletal muscles of healthy mice. Daily injections of CL316,243 for 15 days resulted in a significant improvement in muscle force production, assessed by grip strength and weight tests, and an increased myofiber cross-sectional area, indicative of muscle hypertrophy. In addition, atomic force microscopy revealed a significant effect of CL316,243 on the transversal stiffness of isolated muscle fibers. Interestingly, the expression level of mammalian target of rapamycin (mTOR) downstream targets and neuronal nitric oxide synthase (NOS) was also found to be enhanced in tibialis anterior and soleus muscles of CL316,243 treated mice, in accordance with previous data linking β3-ARs to mTOR and NOS signaling pathways. In conclusion, our data suggest that CL316,243 systemic administration might be a novel therapeutic strategy worthy of further investigations in conditions of muscle wasting and weakness associated with aging and muscular diseases.
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Affiliation(s)
- Daniela Puzzo
- Department of Biomedical and Biotechnological Sciences - Section of Physiology, University of Catania, Catania, Italy
| | - Roberto Raiteri
- Department of Informatics, Bioengineering, Robotics, and System Engineering, University of Genova, Italy
| | - Clotilde Castaldo
- Department of Public Health, School of Medicine and Surgery, University of Naples Federico II, Naples, Italy
| | - Raffaele Capasso
- Department of Pharmacy, University of Naples Federico II, Naples, Italy
| | - Ester Pagano
- Department of Pharmacy, University of Naples Federico II, Naples, Italy
| | - Mariateresa Tedesco
- Department of Informatics, Bioengineering, Robotics, and System Engineering, University of Genova, Italy
| | - Walter Gulisano
- Department of Biomedical and Biotechnological Sciences - Section of Physiology, University of Catania, Catania, Italy
| | - Lisaveta Drozd
- Department of Informatics, Bioengineering, Robotics, and System Engineering, University of Genova, Italy
| | | | - Agostino Palmeri
- Department of Biomedical and Biotechnological Sciences - Section of Physiology, University of Catania, Catania, Italy
| | - Pietro Scotto
- Department of Pharmacy, University of Naples Federico II, Naples, Italy
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30
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Fujikawa T, Castorena CM, Pearson M, Kusminski CM, Ahmed N, Battiprolu PK, Kim KW, Lee S, Hill JA, Scherer PE, Holland WL, Elmquist JK. SF-1 expression in the hypothalamus is required for beneficial metabolic effects of exercise. eLife 2016; 5:e18206. [PMID: 27874828 DOI: 10.7554/elife.15092.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 11/14/2016] [Indexed: 05/26/2023] Open
Abstract
Exercise has numerous beneficial metabolic effects. The central nervous system (CNS) is critical for regulating energy balance and coordinating whole body metabolism. However, a role for the CNS in the regulation of metabolism in the context of the exercise remains less clear. Here, using genetically engineered mice we assessed the requirement of steroidogenic factor-1 (SF-1) expression in neurons of the ventromedial hypothalamic nucleus (VMH) in mediating the beneficial effects of exercise on metabolism. We found that VMH-specific deletion of SF-1 blunts (a) the reductions in fat mass, (b) improvements in glycemia, and (c) increases in energy expenditure that are associated with exercise training. Unexpectedly, we found that SF-1 deletion in the VMH attenuates metabolic responses of skeletal muscle to exercise, including induction of PGC-1α expression. Collectively, this evidence suggests that SF-1 expression in VMH neurons is required for the beneficial effects of exercise on metabolism.
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Affiliation(s)
- Teppei Fujikawa
- Department of Internal Medicine, Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, United States
| | - Carlos M Castorena
- Department of Internal Medicine, Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, United States
| | - Mackenzie Pearson
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, United States
| | - Christine M Kusminski
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, United States
| | - Newaz Ahmed
- Department of Internal Medicine, Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, United States
| | - Pavan K Battiprolu
- Department of Internal Medicine, Division of Cardiology, University of Texas Southwestern Medical Center, Dallas, United States
| | - Ki Woo Kim
- Department of Pharmacology, Wonju College of Medicine, Yonsei University, Wonju, South Korea
- Department of Global Medical Science, Wonju College of Medicine, Yonsei University, Wonju, South Korea
- Institute of Lifestyle Medicine and Nuclear Receptor Research Consortium, Wonju College of Medicine, Yonsei University, Wonju, South Korea
| | - Syann Lee
- Department of Internal Medicine, Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, United States
| | - Joseph A Hill
- Department of Internal Medicine, Division of Cardiology, University of Texas Southwestern Medical Center, Dallas, United States
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, United States
| | - Philipp E Scherer
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, United States
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, United States
| | - William L Holland
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, United States
| | - Joel K Elmquist
- Department of Internal Medicine, Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, United States
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, United States
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31
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Shimamoto S, Ijiri D, Nakashima K, Kawaguchi M, Ishimaru Y, Furukawa A, Ohtsuka A. Clenbuterol changes phosphorylated FOXO1 localization and decreases protein degradation in the sartorius muscle of neonatal chicks. Biosci Biotechnol Biochem 2016; 80:1499-504. [DOI: 10.1080/09168451.2016.1158629] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Abstract
To investigate the intracellular signaling mechanisms by which clenbuterol reduces muscle protein degradation, we examined the phosphorylation level and intracellular localization of FOXO1 in the sartorius muscle of neonatal chicks. One-day-old chicks were given a single intraperitoneal injection of clenbuterol (0.1 mg/kg body weight). Three hours after injection, AKT protein was phosphorylated in the sartorius muscle by clenbuterol injection. Coincidentally, clenbuterol increased cytosolic level of phosphorylated FOXO1 protein, while it decreased nuclear level of FOXO1 protein in the sartorius muscle. Furthermore, clenbuterol decreased the expression of mRNAs for muscle-specific ubiquitin ligases (atrogin-1/MAFbx and MuRF1) in the sartorius muscle accompanied by decreased plasma 3-methylhistidine concentration, an index of muscle protein degradation, at 3 h after injection. These results suggested that, in the sartorius muscle of the chicks, clenbuterol changed the intracellular localization of phosphorylated FOXO1, and consequently decreased protein degradation via suppressing the expression of genes encoding muscle-specific ubiquitin ligases.
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Affiliation(s)
- Saki Shimamoto
- Department of Biochemical Science and Technology, Kagoshima University, Kagoshima, Japan
| | - Daichi Ijiri
- Department of Biochemical Science and Technology, Kagoshima University, Kagoshima, Japan
| | - Kazuki Nakashima
- Animal Physiology and Nutrition Division, NARO Institute of Livestock and Grassland Science, Tsukuba, Japan
| | - Mana Kawaguchi
- Department of Biochemical Science and Technology, Kagoshima University, Kagoshima, Japan
| | - Yoshitaka Ishimaru
- Department of Biochemical Science and Technology, Kagoshima University, Kagoshima, Japan
| | - Airi Furukawa
- Department of Biochemical Science and Technology, Kagoshima University, Kagoshima, Japan
| | - Akira Ohtsuka
- Department of Biochemical Science and Technology, Kagoshima University, Kagoshima, Japan
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32
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Brown DM, Williams H, Ryan KJP, Wilson TL, Daniel ZCTR, Mareko MHD, Emes RD, Harris DW, Jones S, Wattis JAD, Dryden IL, Hodgman TC, Brameld JM, Parr T. Mitochondrial phosphoenolpyruvate carboxykinase (PEPCK-M) and serine biosynthetic pathway genes are co-ordinately increased during anabolic agent-induced skeletal muscle growth. Sci Rep 2016; 6:28693. [PMID: 27350173 PMCID: PMC4923900 DOI: 10.1038/srep28693] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 06/08/2016] [Indexed: 02/04/2023] Open
Abstract
We aimed to identify novel molecular mechanisms for muscle growth during administration of anabolic agents. Growing pigs (Duroc/(Landrace/Large-White)) were administered Ractopamine (a beta-adrenergic agonist; BA; 20 ppm in feed) or Reporcin (recombinant growth hormone; GH; 10 mg/48 hours injected) and compared to a control cohort (feed only; no injections) over a 27-day time course (1, 3, 7, 13 or 27-days). Longissimus Dorsi muscle gene expression was analyzed using Agilent porcine transcriptome microarrays and clusters of genes displaying similar expression profiles were identified using a modified maSigPro clustering algorithm. Anabolic agents increased carcass (p = 0.002) and muscle weights (Vastus Lateralis: p < 0.001; Semitendinosus: p = 0.075). Skeletal muscle mRNA expression of serine/one-carbon/glycine biosynthesis pathway genes (Phgdh, Psat1 and Psph) and the gluconeogenic enzyme, phosphoenolpyruvate carboxykinase-M (Pck2/PEPCK-M), increased during treatment with BA, and to a lesser extent GH (p < 0.001, treatment x time interaction). Treatment with BA, but not GH, caused a 2-fold increase in phosphoglycerate dehydrogenase (PHGDH) protein expression at days 3 (p < 0.05) and 7 (p < 0.01), and a 2-fold increase in PEPCK-M protein expression at day 7 (p < 0.01). BA treated pigs exhibit a profound increase in expression of PHGDH and PEPCK-M in skeletal muscle, implicating a role for biosynthetic metabolic pathways in muscle growth.
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Affiliation(s)
- D M Brown
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
| | - H Williams
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK.,School of Mathematical Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - K J P Ryan
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
| | - T L Wilson
- VMRD Global Therapeutics Research, Zoetis, Kalamazoo, MI, 49007, USA
| | - Z C T R Daniel
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
| | - M H D Mareko
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
| | - R D Emes
- School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
| | - D W Harris
- VMRD Global Therapeutics Research, Zoetis, Kalamazoo, MI, 49007, USA
| | - S Jones
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
| | - J A D Wattis
- School of Mathematical Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - I L Dryden
- School of Mathematical Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - T C Hodgman
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
| | - J M Brameld
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
| | - T Parr
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
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33
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Gómez-SanMiguel AB, Gomez-Moreira C, Nieto-Bona MP, Fernández-Galaz C, Villanúa MÁ, Martín AI, López-Calderón A. Formoterol decreases muscle wasting as well as inflammation in the rat model of rheumatoid arthritis. Am J Physiol Endocrinol Metab 2016; 310:E925-37. [PMID: 27245339 DOI: 10.1152/ajpendo.00503.2015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 03/27/2016] [Indexed: 12/19/2022]
Abstract
Adjuvant-induced arthritis is an experimental model of rheumatoid arthritis that is associated with body weight loss and muscle wasting. β2-adrenergic receptor agonists are powerful anabolic agents that trigger skeletal muscle hypertrophy and have been proposed as a promising treatment for muscle wasting in human patients. The aim of this work was to determine whether formoterol, a selective β2-adrenoreceptor agonist, is able to ameliorate muscle wasting in arthritic rats. Arthritis was induced in male Wistar rats by intradermal injection of Freund's adjuvant. Control and arthritic rats were injected daily with 50 μg/kg sc formoterol or saline for 12 days. Body weight change, food intake, and arthritis index were analyzed. After euthanasia, in the gastrocnemius mRNA was analyzed by PCR, and proteins were analyzed by Western blotting. Arthritis decreased gastrocnemius weight, cross-sectional area, and myofiber size, whereas formoterol increased those variables in both arthritic and control rats. Formoterol decreased the external signs of arthritis as well as NF-κB(p65) activation, TNFα, and COX-2 levels in the gastrocnemius of arthritic and control rats. Those effects of formoterol were associated with a decreased expression of myostatin, atrogin-1, and MuRF1 and in LC3b lipidation. Arthritis increased the expression of MyoD, myogenin, IGF-I, and IGFBP-3 and -5 in the gastrocnemius. In control and in arthritic rats, treatment with formoterol increased Akt phosphorylation and myogenin levels, whereas it decreased IGFBP-3 expression in the gastrocnemius. These data suggest that formoterol has an anti-inflammatory effect and decreases muscle wasting in arthritic rats through increasing Akt activity and myogenin and decreasing myostatin, the p-NF-κB(p65)/TNF pathway, and IGFBP-3.
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Affiliation(s)
| | - Carolina Gomez-Moreira
- Department of Physiology, Faculty of Medicine, Complutense University, Madrid, Spain; and
| | - María Paz Nieto-Bona
- Department of Basic Sciences in Health, Faculty of Health Sciences, Rey Juan Carlos University, Madrid, Spain
| | - Carmen Fernández-Galaz
- Department of Physiology, Faculty of Medicine, Complutense University, Madrid, Spain; and
| | - Maria Ángeles Villanúa
- Department of Physiology, Faculty of Medicine, Complutense University, Madrid, Spain; and
| | - Ana Isabel Martín
- Department of Physiology, Faculty of Medicine, Complutense University, Madrid, Spain; and
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34
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Parr T, Mareko MHD, Ryan KJP, Hemmings KM, Brown DM, Brameld JM. The impact of growth promoters on muscle growth and the potential consequences for meat quality. Meat Sci 2016; 120:93-99. [PMID: 27179582 DOI: 10.1016/j.meatsci.2016.04.022] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 04/17/2016] [Accepted: 04/19/2016] [Indexed: 12/21/2022]
Abstract
To meet the demands of increased global meat consumption, animal production systems will have to become more efficient, or at least maintain the current efficiency utilizing feed ingredients that are not also used for human consumption. Use of growth promoters is a potential option for increasing production animal feed efficiency and increased muscle growth. The objective of this manuscript is to describe the mechanisms by which the growth promoters, beta-adrenergic agonists and growth hormone, mediate their effects, with specific consideration of the aspects which have implications for meat quality.
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Affiliation(s)
- Tim Parr
- Division of Nutritional Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, University of Nottingham, Loughborough, Leics LE12 5RD, UK.
| | | | - Kevin J P Ryan
- Division of Nutritional Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, University of Nottingham, Loughborough, Leics LE12 5RD, UK
| | - Krystal M Hemmings
- College of Life and Natural Sciences, Department of Natural Sciences, University of Derby, Derby DE22 1GB, UK
| | - David M Brown
- Division of Nutritional Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, University of Nottingham, Loughborough, Leics LE12 5RD, UK
| | - John M Brameld
- Division of Nutritional Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, University of Nottingham, Loughborough, Leics LE12 5RD, UK
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35
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Using AAV vectors expressing the β2-adrenoceptor or associated Gα proteins to modulate skeletal muscle mass and muscle fibre size. Sci Rep 2016; 6:23042. [PMID: 26972746 PMCID: PMC4789796 DOI: 10.1038/srep23042] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 02/25/2016] [Indexed: 01/06/2023] Open
Abstract
Anabolic β2-adrenoceptor (β2-AR) agonists have been proposed as therapeutics for treating muscle wasting but concerns regarding possible off-target effects have hampered their use. We investigated whether β2-AR-mediated signalling could be modulated in skeletal muscle via gene delivery to the target tissue, thereby avoiding the risks of β2-AR agonists. In mice, intramuscular administration of a recombinant adeno-associated virus-based vector (rAAV vector) expressing the β2-AR increased muscle mass by >20% within 4 weeks. This hypertrophic response was comparable to that of 4 weeks’ treatment with the β2-AR agonist formoterol, and was not ablated by mTOR inhibition. Increasing expression of inhibitory (Gαi2) and stimulatory (GαsL) G-protein subunits produced minor atrophic and hypertrophic changes in muscle mass, respectively. Furthermore, Gαi2 over-expression prevented AAV:β2-AR mediated hypertrophy. Introduction of the non-muscle Gαs isoform, GαsXL elicited hypertrophy comparable to that achieved by AAV:β2-AR. Moreover, GαsXL gene delivery was found to be capable of inducing hypertrophy in the muscles of mice lacking functional β1- and β2-ARs. These findings demonstrate that gene therapy-based interventions targeting the β2-AR pathway can promote skeletal muscle hypertrophy independent of ligand administration, and highlight novel methods for potentially modulating muscle mass in settings of disease.
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36
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Law NC, Hunzicker-Dunn ME. Insulin Receptor Substrate 1, the Hub Linking Follicle-stimulating Hormone to Phosphatidylinositol 3-Kinase Activation. J Biol Chem 2015; 291:4547-60. [PMID: 26702053 DOI: 10.1074/jbc.m115.698761] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Indexed: 12/21/2022] Open
Abstract
The ubiquitous phosphatidylinositol 3-kinase (PI3K) signaling pathway regulates many cellular functions. However, the mechanism by which G protein-coupled receptors (GPCRs) signal to activate PI3K is poorly understood. We have used ovarian granulosa cells as a model to investigate this pathway, based on evidence that the GPCR agonist follicle-stimulating hormone (FSH) promotes the protein kinase A (PKA)-dependent phosphorylation of insulin receptor substrate 1 (IRS1) on tyrosine residues that activate PI3K. We report that in the absence of FSH, granulosa cells secrete a subthreshold concentration of insulin-like growth factor-1 (IGF-1) that primes the IGF-1 receptor (IGF-1R) but fails to promote tyrosine phosphorylation of IRS1. FSH via PKA acts to sensitize IRS1 to the tyrosine kinase activity of the IGF-1R by activating protein phosphatase 1 (PP1) to promote dephosphorylation of inhibitory Ser/Thr residues on IRS1, including Ser(789). Knockdown of PP1β blocks the ability of FSH to activate PI3K in the presence of endogenous IGF-1. Activation of PI3K thus requires both PKA-mediated relief of IRS1 inhibition and IGF-1R-dependent tyrosine phosphorylation of IRS1. Treatment with FSH and increasing concentrations of exogenous IGF-1 triggers synergistic IRS1 tyrosine phosphorylation at PI3K-activating residues that persists downstream through protein kinase B (AKT) and FOXO1 (forkhead box protein O1) to drive synergistic expression of genes that underlies follicle maturation. Based on the ability of GPCR agonists to synergize with IGFs to enhance gene expression in other cell types, PP1 activation to relieve IRS1 inhibition may be a more general mechanism by which GPCRs act with the IGF-1R to activate PI3K/AKT.
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Affiliation(s)
- Nathan C Law
- From the School of Molecular Biosciences, Washington State University, Pullman, Washington 99164
| | - Mary E Hunzicker-Dunn
- From the School of Molecular Biosciences, Washington State University, Pullman, Washington 99164
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37
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Bartus RT, Bétourné A, Basile A, Peterson BL, Glass J, Boulis NM. β2-Adrenoceptor agonists as novel, safe and potentially effective therapies for Amyotrophic lateral sclerosis (ALS). Neurobiol Dis 2015; 85:11-24. [PMID: 26459114 DOI: 10.1016/j.nbd.2015.10.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 09/25/2015] [Accepted: 10/08/2015] [Indexed: 02/04/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a chronic and progressive neuromuscular disease for which no cure exists and better treatment options are desperately needed. We hypothesize that currently approved β2-adrenoceptor agonists may effectively treat the symptoms and possibly slow the progression of ALS. Although β2-agonists are primarily used to treat asthma, pharmacologic data from animal models of neuromuscular diseases suggest that these agents may have pharmacologic effects of benefit in treating ALS. These include inhibiting protein degradation, stimulating protein synthesis, inducing neurotrophic factor synthesis and release, positively modulating microglial and systemic immune function, maintaining the structural and functional integrity of motor endplates, and improving energy metabolism. Moreover, stimulation of β2-adrenoceptors can activate a range of downstream signaling events in many different cell types that could account for the diverse array of effects of these agents. The evidence supporting the possible therapeutic benefits of β2-agonists is briefly reviewed, followed by a more detailed review of clinical trials testing the efficacy of β-agonists in a variety of human neuromuscular maladies. The weight of evidence of the potential benefits from treating these diseases supports the hypothesis that β2-agonists may be efficacious in ALS. Finally, ways to monitor and manage the side effects that may arise with chronic administration of β2-agonists are evaluated. In sum, effective, safe and orally-active β2-agonists may provide a novel and convenient means to reduce the symptoms of ALS and possibly delay disease progression, affording a unique opportunity to repurpose these approved drugs for treating ALS, and rapidly transforming the management of this serious, unmet medical need.
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Affiliation(s)
| | | | | | | | - Jonathan Glass
- Dept Neurology and Emory ALS Center, Emory University School of Medicine, Atlanta, GA, United States
| | - Nicholas M Boulis
- Dept Neurosurgery, Emory University School of Medicine, Atlanta, GA, United States
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38
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Hostrup M, Kalsen A, Onslev J, Jessen S, Haase C, Habib S, Ørtenblad N, Backer V, Bangsbo J. Mechanisms underlying enhancements in muscle force and power output during maximal cycle ergometer exercise induced by chronic β2-adrenergic stimulation in men. J Appl Physiol (1985) 2015; 119:475-86. [DOI: 10.1152/japplphysiol.00319.2015] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 07/07/2015] [Indexed: 01/16/2023] Open
Abstract
The study was a randomized placebo-controlled trial investigating mechanisms by which chronic β2-adrenergic stimulation enhances muscle force and power output during maximal cycle ergometer exercise in young men. Eighteen trained men were assigned to an experimental group [oral terbutaline 5 mg/30 kg body weight (bw) twice daily (TER); n = 9] or a control group [placebo (PLA); n = 9] for a 4-wk intervention. No changes were observed with the intervention in PLA. Isometric muscle force of the quadriceps increased ( P ≤ 0.01) by 97 ± 29 N (means ± SE) with the intervention in TER compared with PLA. Peak and mean power output during 30 s of maximal cycling increased ( P ≤ 0.01) by 32 ± 8 and 25 ± 9 W, respectively, with the intervention in TER compared with PLA. Maximal oxygen consumption (V̇o2max) and time to fatigue during incremental cycling did not change with the intervention. Lean body mass increased by 1.95 ± 0.8 kg ( P ≤ 0.05) with the intervention in TER compared with PLA. Change in single fiber cross-sectional area of myosin heavy chain (MHC) I (1,205 ± 558 μm2; P ≤ 0.01) and MHC II fibers (1,277 ± 595 μm2; P ≤ 0.05) of the vastus lateralis muscle was higher for TER than PLA with the intervention, whereas no changes were observed in MHC isoform distribution. Expression of muscle proteins involved in growth, ion handling, lactate production, and clearance increased ( P ≤ 0.05) with the intervention in TER compared with PLA, with no change in oxidative enzymes. Our observations suggest that muscle hypertrophy is the primary mechanism underlying enhancements in muscle force and peak power during maximal cycling induced by chronic β2-adrenergic stimulation in humans.
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Affiliation(s)
- Morten Hostrup
- Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Copenhagen, Denmark
- Department of Respiratory Research, Bispebjerg University Hospital, Copenhagen, Denmark
| | - Anders Kalsen
- Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Copenhagen, Denmark
- Department of Respiratory Research, Bispebjerg University Hospital, Copenhagen, Denmark
| | - Johan Onslev
- Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Copenhagen, Denmark
- Department of Respiratory Research, Bispebjerg University Hospital, Copenhagen, Denmark
| | - Søren Jessen
- Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Copenhagen, Denmark
- Department of Respiratory Research, Bispebjerg University Hospital, Copenhagen, Denmark
| | - Christoffer Haase
- Department of Respiratory Research, Bispebjerg University Hospital, Copenhagen, Denmark
| | - Sajad Habib
- Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Niels Ørtenblad
- Department of Sports Science and Biomechanics, University of Southern Denmark, Odense, Denmark; and
- Swedish Winter Sports Research Centre, Mid Sweden University, Sundsvall, Sweden
| | - Vibeke Backer
- Department of Respiratory Research, Bispebjerg University Hospital, Copenhagen, Denmark
| | - Jens Bangsbo
- Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Copenhagen, Denmark
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39
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Mázala DAG, Grange RW, Chin ER. The role of proteases in excitation-contraction coupling failure in muscular dystrophy. Am J Physiol Cell Physiol 2014; 308:C33-40. [PMID: 25298424 DOI: 10.1152/ajpcell.00267.2013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Duchenne muscular dystrophy (DMD) is one of the most frequent types of muscular dystrophy. Alterations in intracellular calcium (Ca(2+)) handling are thought to contribute to the disease severity in DMD, possibly due to the activation of Ca(2+)-activated proteases. The purpose of this study was twofold: 1) to determine whether prolonged excitation-contraction (E-C) coupling disruption following repeated contractions is greater in animals lacking both dystrophin and utrophin (mdx/Utr(-/-)) compared with mice lacking only dystrophin (mdx); and 2) to assess whether protease inhibition can prevent E-C coupling failure following repeated tetani in these dystrophic mouse models. Excitation-contraction coupling was assessed using Fura-2 ratio, as an index of intracellular free Ca(2+) concentration, in response to electrical stimulation of single muscle fibers from the flexor digitorum brevis muscle. Resting Fura-2 ratio was higher in dystrophic compared with control (Con) fibers, but peak Fura-2 ratios during stimulation were similar in dystrophic and Con fibers. One hour after a series of repeated tetani, peak Fura-2 ratios were reduced by 30 ± 5.6%, 23 ± 2%, and 36 ± 3.1% in mdx, mdx/Utr(+/-), and mdx/Utr(-/-), respectively, with the greatest reduction in mdx/Utr(-/-) fibers (P < 0.05). Protease inhibition attenuated this decrease in peak Fura-2 ratio. These data indicate that E-C coupling impairment after repeated contractions is greatest in fibers lacking both dystrophin and utrophin and that prevention of protease activation can mitigate the prolonged E-C coupling impairment. These data further suggest that acute protease inhibition may be useful in reducing muscle weakness in DMD.
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Affiliation(s)
- Davi A G Mázala
- Department of Kinesiology, School of Public Health, University of Maryland, College Park, Maryland; and
| | - Robert W Grange
- Department of Human Nutrition, Foods and Exercise, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | - Eva R Chin
- Department of Kinesiology, School of Public Health, University of Maryland, College Park, Maryland; and
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Jesinkey SR, Korrapati MC, Rasbach KA, Beeson CC, Schnellmann RG. Atomoxetine prevents dexamethasone-induced skeletal muscle atrophy in mice. J Pharmacol Exp Ther 2014; 351:663-73. [PMID: 25292181 DOI: 10.1124/jpet.114.217380] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Skeletal muscle atrophy remains a clinical problem in numerous pathologic conditions. β2-Adrenergic receptor agonists, such as formoterol, can induce mitochondrial biogenesis (MB) to prevent such atrophy. Additionally, atomoxetine, an FDA-approved norepinephrine reuptake inhibitor, was positive in a cellular assay for MB. We used a mouse model of dexamethasone-induced skeletal muscle atrophy to investigate the potential role of atomoxetine and formoterol to prevent muscle mass loss. Mice were administered dexamethasone once daily in the presence or absence of formoterol (0.3 mg/kg), atomoxetine (0.1 mg/kg), or sterile saline. Animals were euthanized at 8, 16, and 24 hours or 8 days later. Gastrocnemius muscle weights, changes in mRNA and protein expression of peroxisome proliferator-activated receptor-γ coactivator-1 α (PGC-1α) isoforms, ATP synthase β, cytochrome c oxidase subunit I, NADH dehydrogenase (ubiquinone) 1 β subcomplex, 8, ND1, insulin-like growth factor 1 (IGF-1), myostatin, muscle Ring-finger protein-1 (muscle atrophy), phosphorylated forkhead box protein O 3a (p-FoxO3a), Akt, mammalian target of rapamycin (mTOR), and ribosomal protein S6 (rp-S6; muscle hypertrophy) in naive and muscle-atrophied mice were measured. Atomoxetine increased p-mTOR 24 hours after treatment in naïve mice, but did not change any other biomarkers. Formoterol robustly activated the PGC-1α-4-IGF1-Akt-mTOR-rp-S6 pathway and increased p-FoxO3a as early as 8 hours and repressed myostatin at 16 hours. In contrast to what was observed with acute treatment, chronic treatment (7 days) with atomoxetine increased p-Akt and p-FoxO3a, and sustained PGC-1α expression and skeletal muscle mass in dexamethasone-treated mice, in a manner comparable to formoterol. In conclusion, chronic treatment with a low dose of atomoxetine prevented dexamethasone-induced skeletal muscle wasting and supports a potential role in preventing muscle atrophy.
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Affiliation(s)
- Sean R Jesinkey
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina (S.R.J., M.C.K., K.A.R., C.C.B., R.G.S.); and Ralph H. Johnson Veterans Administration Medical Center, Charleston, South Carolina (R.G.S.)
| | - Midhun C Korrapati
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina (S.R.J., M.C.K., K.A.R., C.C.B., R.G.S.); and Ralph H. Johnson Veterans Administration Medical Center, Charleston, South Carolina (R.G.S.)
| | - Kyle A Rasbach
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina (S.R.J., M.C.K., K.A.R., C.C.B., R.G.S.); and Ralph H. Johnson Veterans Administration Medical Center, Charleston, South Carolina (R.G.S.)
| | - Craig C Beeson
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina (S.R.J., M.C.K., K.A.R., C.C.B., R.G.S.); and Ralph H. Johnson Veterans Administration Medical Center, Charleston, South Carolina (R.G.S.)
| | - Rick G Schnellmann
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina (S.R.J., M.C.K., K.A.R., C.C.B., R.G.S.); and Ralph H. Johnson Veterans Administration Medical Center, Charleston, South Carolina (R.G.S.)
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Bruno NE, Kelly KA, Hawkins R, Bramah-Lawani M, Amelio AL, Nwachukwu JC, Nettles KW, Conkright MD. Creb coactivators direct anabolic responses and enhance performance of skeletal muscle. EMBO J 2014; 33:1027-43. [PMID: 24674967 PMCID: PMC4193935 DOI: 10.1002/embj.201386145] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 02/01/2014] [Accepted: 02/20/2014] [Indexed: 12/27/2022] Open
Abstract
During the stress response to intense exercise, the sympathetic nervous system (SNS) induces rapid catabolism of energy reserves through the release of catecholamines and subsequent activation of protein kinase A (PKA). Paradoxically, chronic administration of sympathomimetic drugs (β-agonists) leads to anabolic adaptations in skeletal muscle, suggesting that sympathetic outflow also regulates myofiber remodeling. Here, we show that β-agonists or catecholamines released during intense exercise induce Creb-mediated transcriptional programs through activation of its obligate coactivators Crtc2 and Crtc3. In contrast to the catabolic activity normally associated with SNS function, activation of the Crtc/Creb transcriptional complex by conditional overexpression of Crtc2 in the skeletal muscle of transgenic mice fostered an anabolic state of energy and protein balance. Crtc2-overexpressing mice have increased myofiber cross-sectional area, greater intramuscular triglycerides and glycogen content. Moreover, maximal exercise capacity was enhanced after induction of Crtc2 expression in transgenic mice. Collectively these findings demonstrate that the SNS-adrenergic signaling cascade coordinates a transient catabolic stress response during high-intensity exercise, which is followed by transcriptional reprogramming that directs anabolic changes for recovery and that augments subsequent exercise performance.
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Affiliation(s)
- Nelson E Bruno
- Department of Cancer Biology, The Scripps Research Institute, Scripps FloridaJupiter, FL, USA
- The Center for Diabetes and Metabolic Diseases, The Scripps Research Institute, Scripps FloridaJupiter, FL, USA
| | - Kimberly A Kelly
- Department of Cancer Biology, The Scripps Research Institute, Scripps FloridaJupiter, FL, USA
| | - Richard Hawkins
- Department of Cancer Biology, The Scripps Research Institute, Scripps FloridaJupiter, FL, USA
| | - Mariam Bramah-Lawani
- Department of Cancer Biology, The Scripps Research Institute, Scripps FloridaJupiter, FL, USA
| | - Antonio L Amelio
- Department of Cancer Biology, The Scripps Research Institute, Scripps FloridaJupiter, FL, USA
| | - Jerome C Nwachukwu
- Department of Cancer Biology, The Scripps Research Institute, Scripps FloridaJupiter, FL, USA
| | - Kendall W Nettles
- Department of Cancer Biology, The Scripps Research Institute, Scripps FloridaJupiter, FL, USA
| | - Michael D Conkright
- Department of Cancer Biology, The Scripps Research Institute, Scripps FloridaJupiter, FL, USA
- The Center for Diabetes and Metabolic Diseases, The Scripps Research Institute, Scripps FloridaJupiter, FL, USA
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Ghazanfari N, Morsch M, Tse N, Reddel SW, Phillips WD. Effects of the ß2-adrenoceptor agonist, albuterol, in a mouse model of anti-MuSK myasthenia gravis. PLoS One 2014; 9:e87840. [PMID: 24505322 PMCID: PMC3914858 DOI: 10.1371/journal.pone.0087840] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 12/31/2013] [Indexed: 11/19/2022] Open
Abstract
The β2-adrenergic receptor agonist, albuterol, has been reported beneficial in treating several forms of congenital myasthenia. Here, for the first time, we examined the potential benefit of albuterol in a mouse model of anti-Muscle Specific Kinase (MuSK) myasthenia gravis. Mice received 15 daily injections of IgG from anti-MuSK positive patients, which resulted in whole-body weakness. At neuromuscular junctions in the tibialis anterior and diaphragm muscles the autoantibodies caused loss of postsynaptic acetylcholine receptors, and reduced the amplitudes of the endplate potential and spontaneous miniature endplate potential in the diaphragm muscle. Treatment with albuterol (8 mg/kg/day) during the two-week anti-MuSK injection series reduced the degree of weakness and weight loss, compared to vehicle-treated mice. However, the compound muscle action potential recorded from the gastrocnemius muscle displayed a decremental response in anti-MuSK-injected mice whether treated with albuterol or vehicle. Ongoing albuterol treatment did not increase endplate potential amplitudes compared to vehicle-treated mice nor did it prevent the loss of acetylcholine receptors from motor endplates. On the other hand, albuterol treatment significantly reduced the degree of fragmentation of endplate acetylcholine receptor clusters and increased the extent to which the remaining receptor clusters were covered by synaptophysin-stained nerve terminals. The results provide the first evidence that short-term albuterol treatment can ameliorate weakness in a robust mouse model of anti-MuSK myasthenia gravis. The results also demonstrate that it is possible for albuterol treatment to reduce whole-body weakness without necessarily reversing myasthenic impairment to the structure and function of the neuromuscular junction.
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MESH Headings
- Adrenergic beta-2 Receptor Agonists/pharmacology
- Albuterol/pharmacology
- Animals
- Autoantibodies/immunology
- Autoantibodies/toxicity
- Female
- Humans
- Mice
- Muscle, Skeletal/immunology
- Muscle, Skeletal/pathology
- Myasthenia Gravis, Autoimmune, Experimental/chemically induced
- Myasthenia Gravis, Autoimmune, Experimental/drug therapy
- Myasthenia Gravis, Autoimmune, Experimental/immunology
- Myasthenia Gravis, Autoimmune, Experimental/pathology
- Neuromuscular Junction/immunology
- Neuromuscular Junction/pathology
- Receptor Protein-Tyrosine Kinases/immunology
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Affiliation(s)
- Nazanin Ghazanfari
- Physiology and Bosch Institute, University of Sydney, Sydney, New South Wales, Australia
| | - Marco Morsch
- Physiology and Bosch Institute, University of Sydney, Sydney, New South Wales, Australia
| | - Nigel Tse
- Physiology and Bosch Institute, University of Sydney, Sydney, New South Wales, Australia
| | - Stephen W. Reddel
- Department of Molecular Medicine, Concord Hospital, Concord, New South Wales, Australia
| | - William D. Phillips
- Physiology and Bosch Institute, University of Sydney, Sydney, New South Wales, Australia
- * E-mail:
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Abstract
The molecular mechanisms underlying skeletal muscle maintenance involve interplay between multiple signaling pathways. Under normal physiological conditions, a network of interconnected signals serves to control and coordinate hypertrophic and atrophic messages, culminating in a delicate balance between muscle protein synthesis and proteolysis. Loss of skeletal muscle mass, termed "atrophy", is a diagnostic feature of cachexia seen in settings of cancer, heart disease, chronic obstructive pulmonary disease, kidney disease, and burns. Cachexia increases the likelihood of death from these already serious diseases. Recent studies have further defined the pathways leading to gain and loss of skeletal muscle as well as the signaling events that induce differentiation and post-injury regeneration, which are also essential for the maintenance of skeletal muscle mass. In this review, we summarize and discuss the relevant recent literature demonstrating these previously undiscovered mediators governing anabolism and catabolism of skeletal muscle.
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Affiliation(s)
- Marc A Egerman
- Novartis Institutes for Biomedical Research , Cambridge, MA , USA
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Joassard OR, Amirouche A, Gallot YS, Desgeorges MM, Castells J, Durieux AC, Berthon P, Freyssenet DG. Regulation of Akt-mTOR, ubiquitin-proteasome and autophagy-lysosome pathways in response to formoterol administration in rat skeletal muscle. Int J Biochem Cell Biol 2013; 45:2444-55. [PMID: 23916784 DOI: 10.1016/j.biocel.2013.07.019] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 07/10/2013] [Accepted: 07/24/2013] [Indexed: 10/26/2022]
Abstract
Administration of β2-agonists triggers skeletal muscle anabolism and hypertrophy. We investigated the time course of the molecular events responsible for rat skeletal muscle hypertrophy in response to 1, 3 and 10 days of formoterol administration (i.p. 2000μg/kg/day). A marked hypertrophy of rat tibialis anterior muscle culminated at day 10. Phosphorylation of Akt, ribosomal protein S6, 4E-BP1 and ERK1/2 was increased at day 3, but returned to control level at day 10. This could lead to a transient increase in protein translation and could explain previous studies that reported increase in protein synthesis following β2-agonist administration. Formoterol administration was also associated with a significant reduction in MAFbx/atrogin-1 mRNA level (day 3), suggesting that formoterol can also affect protein degradation of MAFbx/atrogin1 targeted substrates, including MyoD and eukaryotic initiation factor-3f (eIF3-f). Surprisingly, mRNA level of autophagy-related genes, light chain 3 beta (LC3b) and gamma-aminobutyric acid receptor-associated protein-like 1 (Gabarapl1), as well as lysosomal hydrolases, cathepsin B and cathepsin L, was significantly and transiently increased after 1 and/or 3 days, suggesting that autophagosome formation would be increased in response to formoterol administration. However, this has to be relativized since the mRNA level of Unc-51-like kinase1 (Ulk1), BCL2/adenovirus E1B interacting protein3 (Bnip3), and transcription factor EB (TFEB), as well as the protein content of Ulk1, Atg13, Atg5-Atg12 complex and p62/Sqstm1 remained unchanged or was even decreased in response to formoterol administration. These results demonstrate that the effects of formoterol are mediated, in part, through the activation of Akt-mTOR pathway and that other signaling pathways become more important in the regulation of skeletal muscle mass with chronic administration of β2-agonists.
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Affiliation(s)
- Olivier Roger Joassard
- Laboratoire de Physiologie de l'Exercice, Université de Lyon, F-42023 Saint-Etienne, France
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45
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Martins KJB, Gehrig SM, Naim T, Saenger S, Baum D, Metzger F, Lynch GS. Intramuscular administration of PEGylated IGF-I improves skeletal muscle regeneration after myotoxic injury. Growth Horm IGF Res 2013; 23:128-133. [PMID: 23608055 DOI: 10.1016/j.ghir.2013.03.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 02/13/2013] [Accepted: 03/13/2013] [Indexed: 11/17/2022]
Abstract
OBJECTIVE Musculoskeletal injuries represent a major public health problem and drugs that can improve muscle repair and restore function are needed for patients with these conditions and other related muscular pathologies. Increasing insulin-like growth factor-I (IGF-I) levels in skeletal muscle improves regeneration after myotoxic injury and while administration of IGF-I has a potential for accelerating healing after trauma, optimizing its method of delivery and obviating potential side-effects currently associated with recombinant human (rh) IGF-I, remain a hurdle. DESIGN We compared the treatment efficacy of rhIGF-I with a polyethylene glycol modified IGF-I (PEG-IGF-I) analog to improve functional repair of mouse tibialis anterior muscles after myotoxic injury, testing the hypothesis that PEG-IGF-I would exert greater beneficial effects on regenerating skeletal muscles than rhIGF-I due to improved pharmacokinetic properties. We also examined the relative efficacy of systemic versus local delivery of these IGF-I variants for improving functional muscle regeneration. RESULTS Local delivery of PEG-IGF-I, but not rhIGF-I, at 4 days post-injury significantly improved early functional recovery as evident by a 27% increase in normalized force compared with saline control (P<0.05), whereas systemic application of either IGF-I variant was not effective. The improved function with intramuscular PEG-IGF-I administration was attributed to a greater and prolonged residence within the regenerating muscles, resulting in increased Akt activation and a 13% larger fiber cross-sectional area compared with rhIGF-I (P<0.05). CONCLUSIONS These data support the hypothesis that PEG-IGF-I is more efficacious than rhIGF-I in hastening early fiber regeneration and improving muscle function after injury, highlighting its therapeutic potential for muscular pathologies.
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Affiliation(s)
- Karen J B Martins
- Basic and Clinical Myology Laboratory, Department of Physiology, The University of Melbourne, Victoria 3010, Australia
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46
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Joassard OR, Durieux AC, Freyssenet DG. β2-Adrenergic agonists and the treatment of skeletal muscle wasting disorders. Int J Biochem Cell Biol 2013; 45:2309-21. [PMID: 23845739 DOI: 10.1016/j.biocel.2013.06.025] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 06/14/2013] [Accepted: 06/26/2013] [Indexed: 02/04/2023]
Abstract
β2-Agonists are traditionally used for the treatment of bronchospasm associated with asthma and the treatment of symptomatic patients with COPD. However, β2-agonists are also powerful anabolic agents that trigger skeletal muscle hypertrophy. Investigating the effects of β2-agonists in skeletal muscle over the past 30 years in different animal models has led to the identification of potential therapeutic applications in several muscle wasting disorders, including neuromuscular diseases, cancer cachexia, sepsis or thermal injury. In these conditions, numerous studies indicate that β2-agonists can attenuate and/or reverse the decrease in skeletal muscle mass and associated weakness in animal models of muscle wasting but also in human patients. The purpose of this review is to present the biological and clinical significance of β2-agonists for the treatment of skeletal muscle wasting. After the description of the molecular mechanisms involved in the hypertrophy and anti-atrophy effect of β2-agonists, we will review the anti-atrophy effects of β2-agonist administration in several animal models and human pathologies associated with or leading to skeletal muscle wasting. This article is part of a Directed Issue entitled: Molecular basis of muscle wasting.
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Affiliation(s)
- Olivier R Joassard
- Laboratoire de Physiologie de l'Exercice, Université de Lyon, F-42023 Saint-Etienne, France
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47
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Schiaffino S, Dyar KA, Ciciliot S, Blaauw B, Sandri M. Mechanisms regulating skeletal muscle growth and atrophy. FEBS J 2013; 280:4294-314. [PMID: 23517348 DOI: 10.1111/febs.12253] [Citation(s) in RCA: 942] [Impact Index Per Article: 85.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 03/13/2013] [Accepted: 03/14/2013] [Indexed: 12/11/2022]
Abstract
Skeletal muscle mass increases during postnatal development through a process of hypertrophy, i.e. enlargement of individual muscle fibers, and a similar process may be induced in adult skeletal muscle in response to contractile activity, such as strength exercise, and specific hormones, such as androgens and β-adrenergic agonists. Muscle hypertrophy occurs when the overall rates of protein synthesis exceed the rates of protein degradation. Two major signaling pathways control protein synthesis, the IGF1-Akt-mTOR pathway, acting as a positive regulator, and the myostatin-Smad2/3 pathway, acting as a negative regulator, and additional pathways have recently been identified. Proliferation and fusion of satellite cells, leading to an increase in the number of myonuclei, may also contribute to muscle growth during early but not late stages of postnatal development and in some forms of muscle hypertrophy in the adult. Muscle atrophy occurs when protein degradation rates exceed protein synthesis, and may be induced in adult skeletal muscle in a variety of conditions, including starvation, denervation, cancer cachexia, heart failure and aging. Two major protein degradation pathways, the proteasomal and the autophagic-lysosomal pathways, are activated during muscle atrophy and variably contribute to the loss of muscle mass. These pathways involve a variety of atrophy-related genes or atrogenes, which are controlled by specific transcription factors, such as FoxO3, which is negatively regulated by Akt, and NF-κB, which is activated by inflammatory cytokines.
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48
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Murphy KT, Struk A, Malcontenti-Wilson C, Christophi C, Lynch GS. Physiological characterization of a mouse model of cachexia in colorectal liver metastases. Am J Physiol Regul Integr Comp Physiol 2013; 304:R854-64. [PMID: 23485871 DOI: 10.1152/ajpregu.00057.2013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Loss of skeletal muscle mass and function (cachexia) is severe in patients with colorectal liver metastases because of the large increase in resting energy expenditure but remains understudied because of a lack of suitable preclinical models. Our aim was to characterize a novel preclinical model of cachexia in colorectal liver metastases. We tested the hypothesis that mice with colorectal liver metastases would exhibit cachexia, as evidenced by a reduction in liver-free body mass, muscle mass, and physiological impairment. Twelve-week-old male CBA mice received an intrasplenic injection of Ringer solution (sham) or murine colorectal cancer cells (MoCR) to induce colorectal liver metastases. At end-point (20-29 days), the livers of MoCR mice were infiltrated completely with metastases, and MoCR mice had reduced liver-free body mass, muscle mass, and epididymal fat mass compared with sham controls (P < 0.03). MoCR mice exhibited impaired rotarod performance and grip strength (P < 0.03). Histochemical analyses of tibialis anterior muscles from MoCR mice revealed muscle fiber atrophy and reduced oxidative enzyme activity (P < 0.001). Adipose tissue remodeling was evident in MoCR mice, with reduced adipocyte diameter and greater infiltration of nonadipocyte tissue (P < 0.05). These findings reveal the MoCR mouse model exhibits significant cachexia and is a suitable preclinical model of cachexia in colorectal liver metastases. This model should be used for identifying effective treatments for cachexia to improve quality of life and reduce mortality in patients with colorectal liver metastases.
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Affiliation(s)
- Kate T Murphy
- Basic and Clinical Myology Laboratory, Department of Physiology, The University of Melbourne, Victoria, Australia.
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49
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Thanawala VJ, Forkuo GS, Al-Sawalha N, Azzegagh Z, Nguyen LP, Eriksen JL, Tuvim MJ, Lowder TW, Dickey BF, Knoll BJ, Walker JKL, Bond RA. β2-Adrenoceptor agonists are required for development of the asthma phenotype in a murine model. Am J Respir Cell Mol Biol 2012. [PMID: 23204390 DOI: 10.1165/rcmb.2012-0364oc] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
β(2)-Adrenoceptor (β2AR) agonists are the most effective class of bronchodilators and a mainstay of asthma management. The first potent β2AR agonist discovered and widely used in reversing the airway constriction associated with asthma exacerbation was the endogenous activator of the β2AR, epinephrine. In this study, we demonstrate that activation of the β2AR by epinephrine is paradoxically required for development of the asthma phenotype. In an antigen-driven model, mice sensitized and challenged with ovalbumin showed marked elevations in three cardinal features of the asthma phenotype: inflammatory cells in their bronchoalveolar lavage fluid, mucin over production, and airway hyperresponsiveness. However, genetic depletion of epinephrine using mice lacking the enzyme to synthesize epinephrine, phenylethanolamine N-methyltransferase, or mice that had undergone pharmacological sympathectomy with reserpine to deplete epinephrine, had complete attenuation of these three cardinal features of the asthma phenotype. Furthermore, administration of the long-acting β2AR agonist, formoterol, a drug currently used in asthma treatment, to phenylethanolamine N-methyltransferase-null mice restored the asthma phenotype. We conclude that β2AR agonist-induced activation is needed for pathogenesis of the asthma phenotype. These findings also rule out constitutive signaling by the β2AR as sufficient to drive the asthma phenotype, and may help explain why chronic administration of β2AR agonists, such as formoterol, have been associated with adverse outcomes in asthma. These data further support the hypothesis that chronic asthma management may be better served by treatment with certain "β-blockers."
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Affiliation(s)
- Vaidehi J Thanawala
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Houston, TX 77204-5037, USA
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50
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Voltarelli VA, Bacurau AVN, Bechara LRG, Bueno CR, Bozi LHM, Mattos KC, Salemi VMC, Brum PC. Lack of β2-AR improves exercise capacity and skeletal muscle oxidative phenotype in mice. Scand J Med Sci Sports 2012; 22:e125-32. [PMID: 22913394 DOI: 10.1111/j.1600-0838.2012.01519.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/24/2012] [Indexed: 01/05/2023]
Abstract
β(2)-adrenergic receptor (β(2)-AR) agonists have been used as ergogenics by athletes involved in training for strength and power in order to increase the muscle mass. Even though anabolic effects of β(2)-AR activation are highly recognized, less is known about the impact of β(2)-AR in endurance capacity. We presently used mice lacking β(2)-AR [β(2)-knockout (β(2) KO)] to investigate the role of β(2)-AR on exercise capacity and skeletal muscle metabolism and phenotype. β(2) KO mice and their wild-type controls (WT) were studied. Exercise tolerance, skeletal muscle fiber typing, capillary-to-fiber ratio, citrate synthase activity and glycogen content were evaluated. When compared with WT, β(2) KO mice displayed increased exercise capacity (61%) associated with higher percentage of oxidative fibers (21% and 129% of increase in soleus and plantaris muscles, respectively) and capillarity (31% and 20% of increase in soleus and plantaris muscles, respectively). In addition, β(2) KO mice presented increased skeletal muscle citrate synthase activity (10%) and succinate dehydrogenase staining. Likewise, glycogen content (53%) and periodic acid-Schiff staining (glycogen staining) were also increased in β(2) KO skeletal muscle. Altogether, these data provide evidence that disruption of β(2)-AR improves oxidative metabolism in skeletal muscle of β(2) KO mice and this is associated with increased exercise capacity.
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Affiliation(s)
- V A Voltarelli
- School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
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