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Grima-Terrén M, Campanario S, Ramírez-Pardo I, Cisneros A, Hong X, Perdiguero E, Serrano AL, Isern J, Muñoz-Cánoves P. Muscle aging and sarcopenia: The pathology, etiology, and most promising therapeutic targets. Mol Aspects Med 2024; 100:101319. [PMID: 39312874 DOI: 10.1016/j.mam.2024.101319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 09/13/2024] [Accepted: 09/16/2024] [Indexed: 09/25/2024]
Abstract
Sarcopenia is a progressive muscle wasting disorder that severely impacts the quality of life of elderly individuals. Although the natural aging process primarily causes sarcopenia, it can develop in response to other conditions. Because muscle function is influenced by numerous changes that occur with age, the etiology of sarcopenia remains unclear. However, recent characterizations of the aging muscle transcriptional landscape, signaling pathway disruptions, fiber and extracellular matrix compositions, systemic metabolomic and inflammatory responses, mitochondrial function, and neurological inputs offer insights and hope for future treatments. This review will discuss age-related changes in healthy muscle and our current understanding of how this can deteriorate into sarcopenia. As our elderly population continues to grow, we must understand sarcopenia and find treatments that allow individuals to maintain independence and dignity throughout an extended lifespan.
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Affiliation(s)
- Mercedes Grima-Terrén
- Altos Labs, San Diego Institute of Science, San Diego, CA, 92121, USA; Department of Medicine and Life Sciences, Universitat Pompeu Fabra (UPF), Barcelona, 08003, Spain
| | - Silvia Campanario
- Altos Labs, San Diego Institute of Science, San Diego, CA, 92121, USA; Department of Medicine and Life Sciences, Universitat Pompeu Fabra (UPF), Barcelona, 08003, Spain
| | - Ignacio Ramírez-Pardo
- Altos Labs, San Diego Institute of Science, San Diego, CA, 92121, USA; Department of Medicine and Life Sciences, Universitat Pompeu Fabra (UPF), Barcelona, 08003, Spain
| | - Andrés Cisneros
- Altos Labs, San Diego Institute of Science, San Diego, CA, 92121, USA; Department of Medicine and Life Sciences, Universitat Pompeu Fabra (UPF), Barcelona, 08003, Spain
| | - Xiaotong Hong
- Altos Labs, San Diego Institute of Science, San Diego, CA, 92121, USA
| | | | - Antonio L Serrano
- Altos Labs, San Diego Institute of Science, San Diego, CA, 92121, USA
| | - Joan Isern
- Altos Labs, San Diego Institute of Science, San Diego, CA, 92121, USA
| | - Pura Muñoz-Cánoves
- Altos Labs, San Diego Institute of Science, San Diego, CA, 92121, USA; Department of Medicine and Life Sciences, Universitat Pompeu Fabra (UPF), Barcelona, 08003, Spain.
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2
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Kong S, Zhu M, Scarpin MR, Pan D, Jia L, Martinez RE, Alamos S, Vadde BVL, Garcia HG, Qian SB, Brunkard JO, Roeder AHK. DRMY1 promotes robust morphogenesis in Arabidopsis by sustaining the translation of cytokinin-signaling inhibitor proteins. Dev Cell 2024:S1534-5807(24)00512-4. [PMID: 39305905 DOI: 10.1016/j.devcel.2024.08.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 04/15/2024] [Accepted: 08/30/2024] [Indexed: 09/25/2024]
Abstract
Robustness is the invariant development of phenotype despite environmental changes and genetic perturbations. In the Arabidopsis flower bud, four sepals robustly initiate and grow to a constant size to enclose and protect the inner floral organs. We previously characterized the mutant development-related myb-like 1 (drmy1), where 3-5 sepals initiate variably and grow to different sizes, compromising their protective function. The molecular mechanism underlying this loss of robustness was unclear. Here, we show that drmy1 has reduced TARGET OF RAPAMYCIN (TOR) activity, ribosomal content, and translation. Translation reduction decreases the protein level of ARABIDOPSIS RESPONSE REGULATOR7 (ARR7) and ARABIDOPSIS HISTIDINE PHOSPHOTRANSFER PROTEIN 6 (AHP6), two cytokinin-signaling inhibitors that are normally rapidly produced before sepal initiation. The resultant upregulation of cytokinin signaling disrupts robust auxin patterning and sepal initiation. Our work shows that the homeostasis of translation, a ubiquitous cellular process, is crucial for the robust spatiotemporal patterning of organogenesis.
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Affiliation(s)
- Shuyao Kong
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA; Section of Plant Biology, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA
| | - Mingyuan Zhu
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA; Section of Plant Biology, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA
| | - M Regina Scarpin
- Laboratory of Genetics, University of Wisconsin, Madison, WI 53706, USA
| | - David Pan
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA; Section of Plant Biology, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA
| | - Longfei Jia
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Ryan E Martinez
- Laboratory of Genetics, University of Wisconsin, Madison, WI 53706, USA
| | - Simon Alamos
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Feedstocks Division, Joint BioEnergy Institute, Emeryville, CA 94608, USA; Department of Plant and Microbial Biology, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Batthula Vijaya Lakshmi Vadde
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA; Section of Plant Biology, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA
| | - Hernan G Garcia
- Biophysics Graduate Group, University of California at Berkeley, Berkeley, CA 94720, USA; Department of Physics, University of California at Berkeley, Berkeley, CA 94720, USA; Institute for Quantitative Biosciences-QB3, University of California at Berkeley, Berkeley, CA 94720, USA; Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA; Chan Zuckerberg Biohub, San Francisco, San Francisco, CA 94158, USA
| | - Shu-Bing Qian
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Jacob O Brunkard
- Laboratory of Genetics, University of Wisconsin, Madison, WI 53706, USA
| | - Adrienne H K Roeder
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA; Section of Plant Biology, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA.
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3
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You JS, Karaman K, Reyes-Ordoñez A, Lee S, Kim Y, Bashir R, Chen J. Leucyl-tRNA Synthetase Contributes to Muscle Weakness through Mammalian Target of Rapamycin Complex 1 Activation and Autophagy Suppression in a Mouse Model of Duchenne Muscular Dystrophy. THE AMERICAN JOURNAL OF PATHOLOGY 2024; 194:1571-1580. [PMID: 38762116 PMCID: PMC11393824 DOI: 10.1016/j.ajpath.2024.04.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 03/24/2024] [Accepted: 04/05/2024] [Indexed: 05/20/2024]
Abstract
Duchenne muscular dystrophy (DMD), caused by loss-of-function mutations in the dystrophin gene, results in progressive muscle weakness and early fatality. Impaired autophagy is one of the cellular hallmarks of DMD, contributing to the disease progression. Molecular mechanisms underlying the inhibition of autophagy in DMD are not well understood. In the current study, the DMD mouse model mdx was used for the investigation of signaling pathways leading to suppression of autophagy. Mammalian target of rapamycin complex 1 (mTORC1) was hyperactive in the DMD muscles, accompanying muscle weakness and autophagy impairment. Surprisingly, Akt, a well-known upstream regulator of mTORC1, was not responsible for mTORC1 activation or the dystrophic muscle phenotypes. Instead, leucyl-tRNA synthetase (LeuRS) was overexpressed in mdx muscles compared with the wild type. LeuRS activates mTORC1 in a noncanonical mechanism that involves interaction with RagD, an activator of mTORC1. Disrupting LeuRS interaction with RagD by the small-molecule inhibitor BC-LI-0186 reduced mTORC1 activity, restored autophagy, and ameliorated myofiber damage in the mdx muscles. Furthermore, inhibition of LeuRS by BC-LI-0186 improved dystrophic muscle strength in an autophagy-dependent manner. Taken together, our findings uncovered a noncanonical function of the housekeeping protein LeuRS as a potential therapeutic target in the treatment of DMD.
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Affiliation(s)
- Jae-Sung You
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois; Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois; Nick J. Holonyak Micro and Nanotechnology Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois.
| | - Kate Karaman
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Adriana Reyes-Ordoñez
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Soohyun Lee
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Yongdeok Kim
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois; Nick J. Holonyak Micro and Nanotechnology Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Rashid Bashir
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois; Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois; Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois; Nick J. Holonyak Micro and Nanotechnology Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois; Department of Biomedical and Translational Sciences, Carle Illinois College of Medicine, Urbana, Illinois
| | - Jie Chen
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois; Department of Biomedical and Translational Sciences, Carle Illinois College of Medicine, Urbana, Illinois.
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Swiderski K, Naim T, Trieu J, Chee A, Herold MJ, Kueh AJ, Goodman CA, Gregorevic P, Lynch GS. Dystrophin S3059 phosphorylation partially attenuates denervation atrophy in mouse tibialis anterior muscles. Physiol Rep 2024; 12:e16145. [PMID: 39001580 PMCID: PMC11245571 DOI: 10.14814/phy2.16145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 07/02/2024] [Accepted: 07/02/2024] [Indexed: 07/16/2024] Open
Abstract
The dystrophin protein has well-characterized roles in force transmission and maintaining membrane integrity during muscle contraction. Studies have reported decreased expression of dystrophin in atrophying muscles during wasting conditions, and that restoration of dystrophin can attenuate atrophy, suggesting a role in maintaining muscle mass. Phosphorylation of S3059 within the cysteine-rich region of dystrophin enhances binding between dystrophin and β-dystroglycan, and mimicking phosphorylation at this site by site-directed mutagenesis attenuates myotube atrophy in vitro. To determine whether dystrophin phosphorylation can attenuate muscle wasting in vivo, CRISPR-Cas9 was used to generate mice with whole body mutations of S3059 to either alanine (DmdS3059A) or glutamate (DmdS3059E), to mimic a loss of, or constitutive phosphorylation of S3059, on all endogenous dystrophin isoforms, respectively. Sciatic nerve transection was performed on these mice to determine whether phosphorylation of dystrophin S3059 could attenuate denervation atrophy. At 14 days post denervation, atrophy of tibialis anterior (TA) but not gastrocnemius or soleus muscles, was partially attenuated in DmdS3059E mice relative to WT mice. Attenuation of atrophy was associated with increased expression of β-dystroglycan in TA muscles of DmdS3059E mice. Dystrophin S3059 phosphorylation can partially attenuate denervation-induced atrophy, but may have more significant impact in less severe modes of muscle wasting.
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Affiliation(s)
- Kristy Swiderski
- Department of Anatomy and Physiology, Centre for Muscle ResearchThe University of MelbourneMelbourneVictoriaAustralia
| | - Timur Naim
- Department of Anatomy and Physiology, Centre for Muscle ResearchThe University of MelbourneMelbourneVictoriaAustralia
| | - Jennifer Trieu
- Department of Anatomy and Physiology, Centre for Muscle ResearchThe University of MelbourneMelbourneVictoriaAustralia
| | - Annabel Chee
- Department of Anatomy and Physiology, Centre for Muscle ResearchThe University of MelbourneMelbourneVictoriaAustralia
| | - Marco J. Herold
- The Walter and Eliza Hall Institute of Medical ResearchParkvilleVictoriaAustralia
- Department of Medical BiologyThe University of MelbourneMelbourneVictoriaAustralia
- Olivia Newton‐John Cancer Research InstituteHeidelbergVictoriaAustralia
- School of Cancer MedicineLa Trobe UniversityHeidelbergVictoriaAustralia
| | - Andrew J. Kueh
- The Walter and Eliza Hall Institute of Medical ResearchParkvilleVictoriaAustralia
- Department of Medical BiologyThe University of MelbourneMelbourneVictoriaAustralia
- Olivia Newton‐John Cancer Research InstituteHeidelbergVictoriaAustralia
- School of Cancer MedicineLa Trobe UniversityHeidelbergVictoriaAustralia
| | - Craig A. Goodman
- Department of Anatomy and Physiology, Centre for Muscle ResearchThe University of MelbourneMelbourneVictoriaAustralia
| | - Paul Gregorevic
- Department of Anatomy and Physiology, Centre for Muscle ResearchThe University of MelbourneMelbourneVictoriaAustralia
| | - Gordon S. Lynch
- Department of Anatomy and Physiology, Centre for Muscle ResearchThe University of MelbourneMelbourneVictoriaAustralia
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Uda M, Yoshihara T, Ichinoseki‐Sekine N, Baba T. Effects of hindlimb unloading on the mevalonate and mechanistic target of rapamycin complex 1 signaling pathways in a fast-twitch muscle in rats. Physiol Rep 2024; 12:e15969. [PMID: 38453353 PMCID: PMC10920058 DOI: 10.14814/phy2.15969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 02/16/2024] [Accepted: 02/22/2024] [Indexed: 03/09/2024] Open
Abstract
Fast-twitch muscles are less susceptible to disuse atrophy, activate the mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway, and increase protein synthesis under prolonged muscle disuse conditions. However, the mechanism underlying prolonged muscle disuse-induced mTORC1 signaling activation remains unclear. The mevalonate pathway activates the mTORC1 signaling pathway via the prenylation and activation of Ras homolog enriched in brain (Rheb). Therefore, we investigated the effects of hindlimb unloading (HU) for 14 days on the mevalonate and mTORC1 signaling pathways in the plantaris muscle, a fast-twitch muscle, in adult male rats. Rats were divided into HU and control groups. The plantaris muscles of both groups were harvested after the treatment period, and the expression and phosphorylation levels of metabolic and intracellular signaling proteins were analyzed using Western blotting. We found that HU increased the expression of 3-hydroxy-3-methylglutaryl-coenzyme A reductase, the rate-limiting enzyme of the mevalonate pathway, and activated the mTORC1 signaling pathway without activating AKT, an upstream activator of mTORC1. Furthermore, HU increased prenylated Rheb. Collectively, these findings suggest that the activated mevalonate pathway may be involved in the activation of the Rheb/mTORC1 signaling pathway without AKT activation in fast-twitch muscles under prolonged disuse conditions.
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Affiliation(s)
- Munehiro Uda
- School of NursingHirosaki Gakuin UniversityHirosakiAomoriJapan
| | - Toshinori Yoshihara
- Graduate School of Health and Sports ScienceJuntendo UniversityInzaiChibaJapan
| | - Noriko Ichinoseki‐Sekine
- Graduate School of Health and Sports ScienceJuntendo UniversityInzaiChibaJapan
- Faculty of Liberal ArtsThe Open University of JapanChibaJapan
| | - Takeshi Baba
- School of MedicineJuntendo UniversityInzaiChibaJapan
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6
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Cree T, Gomez TR, Timpani CA, Rybalka E, Price JT, Goodman CA. FKBP25 regulates myoblast viability and migration and is differentially expressed in in vivo models of muscle adaptation. FEBS J 2023; 290:4660-4678. [PMID: 37345229 DOI: 10.1111/febs.16894] [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: 09/01/2022] [Revised: 04/18/2023] [Accepted: 06/21/2023] [Indexed: 06/23/2023]
Abstract
FKBP25 (FKBP3 gene) is a dual-domain PPIase protein that consists of a C-terminal PPIase domain and an N-terminal basic tilted helix bundle (BTHB). The PPIase domain of FKBP25 has been shown to bind to microtubules, which has impacts upon microtubule polymerisation and cell cycle progression. Using quantitative proteomics, it was recently found that FKBP25 was expressed in the top 10% of the mouse skeletal muscle proteome. However, to date there have been few studies investigating the role of FKBP25 in non-transformed systems. As such, this study aimed to investigate potential roles for FKBP25 in myoblast viability, migration and differentiation and in adaptation of mature skeletal muscle. Doxycycline-inducible FKBP25 knockdown in C2C12 myoblasts revealed an increase in cell accumulation/viability and migration in vitro that was independent of alterations in tubulin dynamics; however, FKBP25 knockdown had no discernible impact on myoblast differentiation into myotubes. Finally, a series of in vivo models of muscle adaptation were assessed, where it was observed that FKBP25 protein expression was increased in hypertrophy and regeneration conditions (chronic mechanical overload and the mdx model of Duchenne muscular dystrophy) but decreased in an atrophy model (denervation). Overall, the findings of this study establish FKBP25 as a regulator of myoblast viability and migration, with possible implications for satellite cell proliferation and migration and muscle regeneration, and as a potential regulator of in vivo skeletal muscle adaptation.
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Affiliation(s)
- Tabitha Cree
- Institute for Health and Sport (IHeS), Victoria University, Melbourne, Australia
- Australian Institute for Musculoskeletal Science (AIMSS), St Albans, Australia
| | - Tania Ruz Gomez
- Institute for Health and Sport (IHeS), Victoria University, Melbourne, Australia
| | - Cara A Timpani
- Institute for Health and Sport (IHeS), Victoria University, Melbourne, Australia
- Australian Institute for Musculoskeletal Science (AIMSS), St Albans, Australia
| | - Emma Rybalka
- Institute for Health and Sport (IHeS), Victoria University, Melbourne, Australia
- Australian Institute for Musculoskeletal Science (AIMSS), St Albans, Australia
| | - John T Price
- Institute for Health and Sport (IHeS), Victoria University, Melbourne, Australia
- Australian Institute for Musculoskeletal Science (AIMSS), St Albans, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
- Monash Biomedicine Discovery Institute, Clayton, Australia
| | - Craig A Goodman
- Institute for Health and Sport (IHeS), Victoria University, Melbourne, Australia
- Australian Institute for Musculoskeletal Science (AIMSS), St Albans, Australia
- Department of Physiology, Centre for Muscle Research (CMR), The University of Melbourne, Parkville, Australia
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7
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Du Y, Cai X. Therapeutic potential of natural compounds from herbs and nutraceuticals in spinal cord injury: Regulation of the mTOR signaling pathway. Biomed Pharmacother 2023; 163:114905. [PMID: 37207430 DOI: 10.1016/j.biopha.2023.114905] [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: 04/10/2023] [Revised: 05/13/2023] [Accepted: 05/16/2023] [Indexed: 05/21/2023] Open
Abstract
Spinal cord injury (SCI) is a disease in which the spinal cord is subjected to various external forces that cause it to burst, shift, or, in severe cases, injure the spinal tissue, resulting in nerve injury. SCI includes not only acute primary injury but also delayed and persistent spinal tissue injury (i.e., secondary injury). The pathological changes post-SCI are complex, and effective clinical treatment strategies are lacking. The mammalian target of rapamycin (mTOR) coordinates the growth and metabolism of eukaryotic cells in response to various nutrients and growth factors. The mTOR signaling pathway has multiple roles in the pathogenesis of SCI. There is evidence for the beneficial effects of natural compounds and nutraceuticals that regulate the mTOR signaling pathways in a variety of diseases. Therefore, the effects of natural compounds on the pathogenesis of SCI were evaluated by a comprehensive review using electronic databases, such as PubMed, Web of Science, Scopus, and Medline, combined with our expertise in neuropathology. In particular, we reviewed the pathogenesis of SCI, including the importance of secondary nerve injury after the primary mechanical injury, the roles of the mTOR signaling pathways, and the beneficial effects and mechanisms of natural compounds that regulate the mTOR signaling pathway on pathological changes post-SCI, including effects on inflammation, neuronal apoptosis, autophagy, nerve regeneration, and other pathways. This recent research highlights the value of natural compounds in regulating the mTOR pathway, providing a basis for developing novel therapeutic strategies for SCI.
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Affiliation(s)
- Yan Du
- Department of Emergency Medicine, Shengjing Hospital of China Medical University, Shenyang, Liaoning, PR China
| | - Xue Cai
- Department of Emergency Medicine, Shengjing Hospital of China Medical University, Shenyang, Liaoning, PR China.
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8
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Uemichi K, Shirai T, Takemasa T. Combined effects of functional overload and denervation on skeletal muscle mass and its regulatory proteins in mice. Physiol Rep 2023; 11:e15689. [PMID: 37161590 PMCID: PMC10169777 DOI: 10.14814/phy2.15689] [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: 03/21/2023] [Revised: 03/29/2023] [Accepted: 03/31/2023] [Indexed: 05/11/2023] Open
Abstract
Skeletal muscle is a highly pliable tissue and various adaptations such as muscle hypertrophy or atrophy are induced by overloading or disuse, respectively. However, the combined effect of overloading and disuse on the quantitative adaptation of skeletal muscle is unknown. Thus, the aim of this study was to investigate the effects of the combined stimuli of overloading and disuse on mouse skeletal muscle mass and the expression of regulatory factors for muscle protein anabolism or catabolism. Male mice from the Institute Cancer Research were subjected to denervation concomitant with unilateral functional overload or functional overload concomitant with unilateral denervation. Disuse and functional overload were induced by sciatic nerve transection (denervation) and synergist ablation, respectively, and the plantaris muscle was harvested 14 days after the operation. Our results showed that denervation attenuated functional overload-induced muscle hypertrophy and functional overload partially ameliorated the denervation-induced muscle atrophy. P70S6K phosphorylation, an indicator of mechanistic target of rapamycin complex 1 (mTORC1) activation, was not increased by unilateral functional overload in denervated muscles or by unilateral denervation in functional overloaded muscles. Denervation did not affect the increase of LC3-II, a marker of autophagy activation, and ubiquitinated protein expression upon unilateral functional overload. Also, functional overload did not affect ubiquitinated protein expression during unilateral denervation. Thus, our findings suggest that functional overload-induced muscle hypertrophy or denervation-induced muscle atrophy was attenuated by the combined stimuli of overload and denervation.
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Affiliation(s)
- Kazuki Uemichi
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki, Japan
| | - Takanaga Shirai
- Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, Japan
| | - Tohru Takemasa
- Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, Japan
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9
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Sadri H, Ghaffari MH, Sauerwein H. Invited review: Muscle protein breakdown and its assessment in periparturient dairy cows. J Dairy Sci 2023; 106:822-842. [PMID: 36460512 DOI: 10.3168/jds.2022-22068] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 08/29/2022] [Indexed: 11/30/2022]
Abstract
Mobilization of body reserves including fat, protein, and glycogen is necessary to overcome phases of negative nutrient balance typical for high-yielding dairy cows during the periparturient period. Skeletal muscle, the largest internal organ in mammals, plays a crucial role in maintaining metabolic homeostasis. However, unlike in liver and adipose tissue, the metabolic and regulatory role of skeletal muscle in the adaptation of dairy cows to the physiological needs of pregnancy and lactation has not been studied extensively. The functional integrity and quality of skeletal muscle are maintained through a constant turnover of protein, resulting from both protein breakdown and protein synthesis. Thus, muscle protein breakdown (MPB) and synthesis are intimately connected and tightly controlled to ensure proper protein homeostasis. Understanding the regulation of MPB, the catabolic component of muscle turnover, and its assessment are therefore important considerations to provide information about the timing and extent of tissue mobilization in periparturient dairy cows. Based on animal models and human studies, it is now evident that MPB occurs via the integration of 3 main systems: autophagy-lysosomal, calpain Ca2+-dependent cysteine proteases, and the ubiquitin-proteasome system. These 3 main systems are interconnected and do not work separately, and the regulation is complex. The ubiquitin-proteasomal system is the most well-known cellular proteolytic system and plays a fundamental role in muscle physiology. Complete degradation of a protein often requires a combination of the systems, depending on the physiological situation. Determination of MPB in dairy cows is technically challenging, resulting in a relative dearth of information. The methods for assessing MPB can be divided into either direct or indirect measurements, both having their strengths and limitations. Available information on the direct measures of MPB primarily comes from stable isotopic tracer methods and those of indirect measurements from assessing expression and activity measures of the components of the 3 MPB systems in muscle biopsy samples. Other indirect approaches (i.e., potential indicators of MPB), including ultrasound imaging and measuring metabolites from muscle degradation (i.e., 3-methylhistidine and creatinine), seem to be applicable methods and can provide useful information about the extent and timing of MPB. This review presents our current understanding, including methodological considerations, of the process of MPB in periparturient dairy cows.
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Affiliation(s)
- H Sadri
- Department of Clinical Science, Faculty of Veterinary Medicine, University of Tabriz, 5166616471 Tabriz, Iran; Institute of Animal Science, Physiology Unit, University of Bonn, 53111 Bonn, Germany.
| | - M H Ghaffari
- Institute of Animal Science, Physiology Unit, University of Bonn, 53111 Bonn, Germany
| | - H Sauerwein
- Institute of Animal Science, Physiology Unit, University of Bonn, 53111 Bonn, Germany
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10
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Uno H, Kamiya S, Akimoto R, Hosoki K, Tadano S, Kouzaki K, Tamura Y, Kotani T, Isemura M, Nakazato K. Low-frequency electrical stimulation of bilateral hind legs by belt electrodes is effective for preventing denervation-induced atrophies in multiple skeletal muscle groups in rats. Sci Rep 2022; 12:21275. [PMID: 36481829 PMCID: PMC9732041 DOI: 10.1038/s41598-022-25359-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 11/29/2022] [Indexed: 12/13/2022] Open
Abstract
Belt electrode skeletal muscle electrical stimulation (B-SES) can simultaneously contract multiple muscle groups. Although the beneficial effects of B-SES in clinical situations have been elucidated, its molecular mechanism remains unknown. In this study, we developed a novel rodent B-SES ankle stimulation system to test whether low-frequency stimulation prevents denervation-induced muscle atrophy. Electrical stimulations (7‒8 Hz, 30 min) with ankle belt electrodes were applied to Sprague-Dawley rats daily for one week. All animals were assigned to the control (CONT), denervation-induced atrophy (DEN), and DEN + electrical stimulation (ES) groups. The tibialis anterior (TA) and gastrocnemius (GAS) muscles were used to examine the effect of ES treatment. After seven daily sessions of continuous stimulation, muscle wet weight (n = 8-11), and muscle fiber cross-sectional area (CSA, n = 4-6) of TA and GAS muscles were lower in DEN and DEN + ES than in CON. However, it was significantly higher in DEN than DEN + ES, showing that ES partially prevented muscle atrophy. PGC-1α, COX-IV, and citrate synthase activities (n = 6) were significantly higher in DEN + ES than in DEN. The mRNA levels of muscle proteolytic molecules, Atrogin-1 and Murf1, were significantly higher in DEN than in CONT, while B-SES significantly suppressed their expression (p < 0.05). In conclusion, low-frequency electrical stimulation of the bilateral ankles using belt electrodes (but not the pad electrodes) is effective in preventing denervation-induced atrophy in multiple muscles, which has not been observed with pad electrodes. Maintaining the mitochondrial quantity and enzyme activity by low-frequency electrical stimulation is key to suppressing muscle protein degradation.
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Affiliation(s)
- Hiroyuki Uno
- HOMER ION Co., Ltd., Shinsen 17-2, Shibuya-ku, Tokyo, 150-0045 Japan ,grid.412200.50000 0001 2228 003XSchool of Health and Sport Science, Nippon Sport Science University, 7-1-1 Fukazawa, Setagaya-ku, Tokyo, 158-8508 Japan
| | - Shohei Kamiya
- HOMER ION Co., Ltd., Shinsen 17-2, Shibuya-ku, Tokyo, 150-0045 Japan
| | - Ryuji Akimoto
- HOMER ION Co., Ltd., Shinsen 17-2, Shibuya-ku, Tokyo, 150-0045 Japan
| | - Katsu Hosoki
- HOMER ION Co., Ltd., Shinsen 17-2, Shibuya-ku, Tokyo, 150-0045 Japan
| | - Shunta Tadano
- HOMER ION Co., Ltd., Shinsen 17-2, Shibuya-ku, Tokyo, 150-0045 Japan
| | - Karina Kouzaki
- grid.412200.50000 0001 2228 003XSchool of Health and Sport Science, Nippon Sport Science University, 7-1-1 Fukazawa, Setagaya-ku, Tokyo, 158-8508 Japan
| | - Yuki Tamura
- grid.412200.50000 0001 2228 003XSchool of Health and Sport Science, Nippon Sport Science University, 7-1-1 Fukazawa, Setagaya-ku, Tokyo, 158-8508 Japan
| | - Takaya Kotani
- grid.412200.50000 0001 2228 003XSchool of Health and Sport Science, Nippon Sport Science University, 7-1-1 Fukazawa, Setagaya-ku, Tokyo, 158-8508 Japan
| | - Mako Isemura
- HOMER ION Co., Ltd., Shinsen 17-2, Shibuya-ku, Tokyo, 150-0045 Japan ,grid.412200.50000 0001 2228 003XSchool of Health and Sport Science, Nippon Sport Science University, 7-1-1 Fukazawa, Setagaya-ku, Tokyo, 158-8508 Japan
| | - Koichi Nakazato
- grid.412200.50000 0001 2228 003XSchool of Health and Sport Science, Nippon Sport Science University, 7-1-1 Fukazawa, Setagaya-ku, Tokyo, 158-8508 Japan
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11
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Functional Nutrients to Ameliorate Neurogenic Muscle Atrophy. Metabolites 2022; 12:metabo12111149. [DOI: 10.3390/metabo12111149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 11/15/2022] [Accepted: 11/17/2022] [Indexed: 11/22/2022] Open
Abstract
Neurogenic muscle atrophy is a debilitating condition that occurs from nerve trauma in association with diseases or during aging, leading to reduced interaction between motoneurons and skeletal fibers. Current therapeutic approaches aiming at preserving muscle mass in a scenario of decreased nervous input include physical activity and employment of drugs that slow down the progression of the condition yet provide no concrete resolution. Nutritional support appears as a precious tool, adding to the success of personalized medicine, and could thus play a relevant part in mitigating neurogenic muscle atrophy. We herein summarize the molecular pathways triggered by denervation of the skeletal muscle that could be affected by functional nutrients. In this narrative review, we examine and discuss studies pertaining to the use of functional ingredients to counteract neurogenic muscle atrophy, focusing on their preventive or curative means of action within the skeletal muscle. We reviewed experimental models of denervation in rodents and in amyotrophic lateral sclerosis, as well as that caused by aging, considering the knowledge generated with use of animal experimental models and, also, from human studies.
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12
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Rozhkov SV, Sharlo KA, Shenkman BS, Mirzoev TM. Inhibition of mTORC1 differentially affects ribosome biogenesis in rat soleus muscle at the early and later stages of hindlimb unloading. Arch Biochem Biophys 2022; 730:109411. [PMID: 36155780 DOI: 10.1016/j.abb.2022.109411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 07/29/2022] [Accepted: 09/19/2022] [Indexed: 11/02/2022]
Abstract
Prolonged inactivity of skeletal muscles due to limb immobilization, bedrest, and exposure to microgravity results in a significant muscle atrophy. Inactivity-induced muscle atrophy is caused by a downregulation of protein synthesis (PS) and increased proteolysis. Mechanistic target of rapamycin complex 1 (mTORC1) is considered to be one of the main regulators of translational capacity (quantity of ribosomes), a key determinant of PS. Using a specific mTORC1 inhibitor (rapamycin) we aimed to determine if mTORC1 activity would influence ribosome biogenesis in rat soleus muscle at both early and later stages of mechanical unloading. Wistar rats were subjected to 1- and 7-day hindlimb suspension (HS) with and without rapamycin injections (1.5 mg/kg) and compared to weight-bearing control animals. The key markers of ribosome biogenesis were assessed by RT-PCR or agarose gel electrophoresis. The rate of PS was measured by SUnSET method. Both 1-day and 7-day HS resulted in a significant downregulation of ribosome biogenesis markers (c-Myc, 47S pre-rRNA, 18S + 28S rRNAs) and the rate of PS. Rapamycin administration during 1-day HS fully prevented a decrease in 47S pre-rRNA expression and amount of 18S + 28S rRNAs (without affecting c-Myc mRNA expression) and partially attenuated a decline in PS. Rapamycin treatment during 7-day HS significantly decreased p70S6K phosphorylation but failed to rescue a reduction in both the markers of ribosome biogenesis and the rate of PS. All together, our results suggest that mTORC1 inhibition at the initial (1 day), but not later (7 days) stage of HS can be beneficial for the maintenance of translational capacity (ribosome biogenesis) and the rate of PS in rat soleus muscle.
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Affiliation(s)
- Sergey V Rozhkov
- Myology Laboratory, Institute of Biomedical Problems RAS, 123007, 76A Khoroshevskoe shosse, Moscow, Russia
| | - Kristina A Sharlo
- Myology Laboratory, Institute of Biomedical Problems RAS, 123007, 76A Khoroshevskoe shosse, Moscow, Russia
| | - Boris S Shenkman
- Myology Laboratory, Institute of Biomedical Problems RAS, 123007, 76A Khoroshevskoe shosse, Moscow, Russia
| | - Timur M Mirzoev
- Myology Laboratory, Institute of Biomedical Problems RAS, 123007, 76A Khoroshevskoe shosse, Moscow, Russia.
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13
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Cant J, Reyes G, Seymour D. Review: Influence of postabsorptive metabolism on essential amino acid partitioning in lactating dairy cows. Animal 2022; 16 Suppl 3:100573. [DOI: 10.1016/j.animal.2022.100573] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 05/24/2022] [Accepted: 05/30/2022] [Indexed: 01/07/2023] Open
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14
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You JS, Chen J. Aging Does Not Exacerbate Muscle Loss During Denervation and Lends Unique Muscle-Specific Atrophy Resistance With Akt Activation. Front Physiol 2021; 12:779547. [PMID: 34916960 PMCID: PMC8669767 DOI: 10.3389/fphys.2021.779547] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Accepted: 11/09/2021] [Indexed: 01/10/2023] Open
Abstract
Sarcopenia, or age-related skeletal muscle atrophy and weakness, imposes significant clinical and economic burdens on affected patients and societies. Neurological degeneration, such as motoneuron death, has been recognized as a key contributor to sarcopenia. However, little is known about how aged/sarcopenic muscle adapts to this denervation stress. Here, we show that mice at 27months of age exhibit clear signs of sarcopenia but no accelerated denervation-induced muscle atrophy when compared to 8-month-old mice. Surprisingly, aging lends unique atrophy resistance to tibialis anteria muscle, accompanied by an increase in the cascade of mammalian target of rapamycin complex 1 (mTORC1)-independent anabolic events involving Akt signaling, rRNA biogenesis, and protein synthesis during denervation. These results expand our understanding of age-dependent stress responses and may help develop better countermeasures to sarcopenia.
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Affiliation(s)
- Jae-Sung You
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Jie Chen
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
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15
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Osburn SC, Vann CG, Church DD, Ferrando AA, Roberts MD. Proteasome- and Calpain-Mediated Proteolysis, but Not Autophagy, Is Required for Leucine-Induced Protein Synthesis in C2C12 Myotubes. PHYSIOLOGIA 2021; 1:22-33. [PMID: 34927140 PMCID: PMC8681867 DOI: 10.3390/physiologia1010005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Muscle protein synthesis and proteolysis are tightly coupled processes. Given that muscle growth is promoted by increases in net protein balance, it stands to reason that bolstering protein synthesis through amino acids while reducing or inhibiting proteolysis could be a synergistic strategy in enhancing anabolism. However, there is contradictory evidence suggesting that the proper functioning of proteolytic systems in muscle is required for homeostasis. To add clarity to this issue, we sought to determine if inhibiting different proteolytic systems in C2C12 myotubes in conjunction with acute and chronic leucine treatments affected markers of anabolism. In Experiment 1, myotubes underwent 1-h, 6-h, and 24-h treatments with serum and leucine-free DMEM containing the following compounds (n = 6 wells per treatment): (i) DMSO vehicle (CTL), (ii) 2 mM leucine + vehicle (Leu-only), (iii) 2 mM leucine + 40 μM MG132 (20S proteasome inhibitor) (Leu + MG132), (iv) 2 mM leucine + 50 μM calpeptin (calpain inhibitor) (Leu + CALP), and (v) 2 mM leucine + 1 μM 3-methyladenine (autophagy inhibitor) (Leu + 3MA). Protein synthesis levels significantly increased (p < 0.05) in the Leu-only and Leu + 3MA 6-h treatments compared to CTL, and levels were significantly lower in Leu + MG132 and Leu + CALP versus Leu-only and CTL. With 24-h treatments, total protein yield was significantly lower in Leu + MG132 cells versus other treatments. Additionally, the intracellular essential amino acid (EAA) pool was significantly greater in 24-h Leu + MG132 treatments versus other treatments. In a follow-up experiment, myotubes were treated for 48 h with CTL, Leu-only, and Leu + MG132 for morphological assessments. Results indicated Leu + MG132 yielded significantly smaller myotubes compared to CTL and Leu-only. Our data are limited in scope due to the utilization of select proteolysis inhibitors. However, this is the first evidence to suggest proteasome and calpain inhibition with MG132 and CALP, respectively, abrogate leucine-induced protein synthesis in myotubes. Additionally, longer-term Leu + MG132 treatments translated to an atrophy phenotype. Whether or not proteasome inhibition in vivo reduces leucine- or EAA-induced anabolism remains to be determined.
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Affiliation(s)
| | - Christopher G. Vann
- School of Kinesiology, Auburn University, Auburn, AL 36849, USA
- Duke Molecular Physiology Institute, Duke University School of Medicine, Duke University, Durham, NC 27708, USA
| | - David D. Church
- Department of Geriatrics, Donald W. Reynolds Institute on Aging, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Arny A. Ferrando
- Department of Geriatrics, Donald W. Reynolds Institute on Aging, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
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16
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Wang Z, Xia T, Jin S, Liu X, Pan R, Yan M, Chang Q. Chronic Restraint Stress-Induced Muscle Atrophy Leads to Fatigue in Mice by Inhibiting the AMPK Signaling Pathway. Biomedicines 2021; 9:biomedicines9101321. [PMID: 34680438 PMCID: PMC8533263 DOI: 10.3390/biomedicines9101321] [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: 08/11/2021] [Revised: 09/16/2021] [Accepted: 09/23/2021] [Indexed: 11/16/2022] Open
Abstract
Currently, an increasing number of people are suffering from fatigue due to the state of their lifestyles, such as sedentary work in a relatively small space, irregular sleep patterns, or the lack of movement and exercise. The present study was designed to simulate the occurrence of fatigue in the above populations through a chronic restraint stress (CRS) model, and to reveal its dynamic processes and potential underlying molecular mechanisms. ICR mice were subjected to 8 h of restraint stress each day for 5, 10, or 15 days. It was found that the weight-loaded swimming performance, grip strength, and locomotor activity of the mice all decreased under CRS treatment, and that up to 15 days of CRS induced notable fatigue. Gastrocnemius muscle atrophy and some abnormal biochemical parameters related to fatigue under CRS were observed. Furthermore, transcriptome data showed that the changes in muscle cell metabolism and mitochondrial dysfunction were associated with the AMPK signaling pathway in CRS-treated mice. Western blotting analysis of the AMPK/PGC-1α signaling pathway revealed that CRS could decrease mitochondrial biogenesis and reduce the numbers of type I skeletal muscle fibers in the gastrocnemius of mice. CRS could also block the protective mitophagic flux to inhibit the abnormal clearance of damaged mitochondria. Our study suggests a critical link between muscle atrophy and CRS-induced fatigue in mice, suggesting that the pharmacological promotion of muscle and mitochondrial function can be used as a treatment for stress-induced fatigue.
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Affiliation(s)
| | | | | | | | | | - Mingzhu Yan
- Correspondence: (M.Y.); (Q.C.); Tel.: +86-10-5783-3468 (M.Y.); +86-10-5783-3224 (Q.C.)
| | - Qi Chang
- Correspondence: (M.Y.); (Q.C.); Tel.: +86-10-5783-3468 (M.Y.); +86-10-5783-3224 (Q.C.)
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17
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You JS, Kim K, Steinert ND, Chen J, Hornberger TA. mTORC1 mediates fiber type-specific regulation of protein synthesis and muscle size during denervation. Cell Death Discov 2021; 7:74. [PMID: 33846288 PMCID: PMC8042034 DOI: 10.1038/s41420-021-00460-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 03/18/2021] [Accepted: 03/25/2021] [Indexed: 02/07/2023] Open
Abstract
Skeletal muscle denervation occurs in diverse conditions and causes severe muscle atrophy. Signaling by mammalian target of rapamycin complex 1 (mTORC1) plays a central role in the maintenance of skeletal muscle mass by regulating net protein balance; yet, its role in denervation-induced atrophy is unclear. In this study, by using skeletal muscle-specific and inducible raptor knockout mice, we demonstrate that signaling through mTORC1 is activated during denervation and plays an essential role in mitigating the atrophy of non-type IIB muscle fibers. Measurements of protein synthesis rates of individual fibers suggest that denervation increases protein synthesis specifically in non-type IIB muscle fibers and that mTORC1 is required for this event. Furthermore, denervation induced a more pronounced increase in the level of phosphorylated ribosomal S6 protein in non-type IIB muscle fibers than in type IIB muscle fibers. Collectively, our results unveil a novel role for mTORC1 in mediating a fiber type-specific regulation of muscle size and protein synthesis during denervation.
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Affiliation(s)
- Jae-Sung You
- Department of Comparative Biosciences in the School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA.
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
| | - Kookjoo Kim
- Department of Comparative Biosciences in the School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Nathaniel D Steinert
- Department of Comparative Biosciences in the School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Jie Chen
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Troy A Hornberger
- Department of Comparative Biosciences in the School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA.
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18
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Graham ZA, DeBerry JJ, Cardozo CP, Bamman MM. A 50 kdyne contusion spinal cord injury with or without the drug SS-31 was not associated with major changes in muscle mass or gene expression 14 d after injury in young male mice. Physiol Rep 2021; 9:e14751. [PMID: 33611851 PMCID: PMC7897452 DOI: 10.14814/phy2.14751] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 01/09/2021] [Accepted: 01/12/2021] [Indexed: 12/23/2022] Open
Abstract
Spinal cord injury (SCI) leads to rapid muscle atrophy due to paralysis/paresis and subsequent disuse. SS-31 is a mitochondrial-targeting peptide that has shown efficacy in protecting skeletal muscle mass and function in non-SCI models of muscle wasting. We aimed to determine if SS-31 could prevent muscle loss after SCI. Male C57BL/6 mice aged 9 weeks underwent sham surgery or 50 kdyne contusion SCI and were administered daily injections of vehicle or 5 mg/kg SS-31 for 14 d. Both SCI groups had sustained losses in body mass compared to Sham animals and ~10% reductions in gastrocnemius, plantaris and tibialis anterior muscle mass after SCI with no clear effect of SS-31. Measurements of protein synthesis in the soleus and plantaris were similar among all groups. mRNA expression of atrophy-associated proinflammatory cytokines was also similar among all groups. There was elevation in MYH7 mRNA and a statistical reduction in MYH2 mRNA expression in the SCI+SS-31 animals compared to Sham animals. There was an SCI-induced reduction in mRNA expression of the E3 ligase FBXO32 (MAFbx), but no effect of SS-31. In summary, a 50 kdyne contusion SCI was able to reduce body mass but was not associated with substantial muscle atrophy or alterations in gene expression profiles associated with muscle health and function 14 d post-injury. SS-31 was not associated with protection against SCI-related changes in body or muscle mass, protein synthesis or gene expression in hindlimb muscles.
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Affiliation(s)
- Zachary A. Graham
- Research ServiceBirmingham VA Medical CenterBirminghamALUSA
- Department of Cell, Developmental, and Integrative BiologyUniversity of Alabama‐BirminghamBirminghamALUSA
| | - Jennifer J. DeBerry
- Department of Anesthesiology and Perioperative MedicineUniversity of Alabama‐BirminghamBirminghamALUSA
| | - Christopher P. Cardozo
- National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters VA Medical CenterBronxNYUSA
- Medical ServiceJames J. Peters VA Medical CenterBronxNYUSA
- Departments of Medicine and Rehabilitation MedicineIcahn School of Medicine at Mount SinaiNew YorkNYUSA
| | - Marcas M. Bamman
- Research ServiceBirmingham VA Medical CenterBirminghamALUSA
- Department of Cell, Developmental, and Integrative BiologyUniversity of Alabama‐BirminghamBirminghamALUSA
- UAB Center for Exercise MedicineUniversity of Alabama‐BirminghamBirminghamALUSA
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19
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Mizushima N, Murphy LO. Autophagy Assays for Biological Discovery and Therapeutic Development. Trends Biochem Sci 2020; 45:1080-1093. [DOI: 10.1016/j.tibs.2020.07.006] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 07/08/2020] [Accepted: 07/24/2020] [Indexed: 12/14/2022]
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20
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Castets P, Ham DJ, Rüegg MA. The TOR Pathway at the Neuromuscular Junction: More Than a Metabolic Player? Front Mol Neurosci 2020; 13:162. [PMID: 32982690 PMCID: PMC7485269 DOI: 10.3389/fnmol.2020.00162] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 08/05/2020] [Indexed: 12/18/2022] Open
Abstract
The neuromuscular junction (NMJ) is the chemical synapse connecting motor neurons and skeletal muscle fibers. NMJs allow all voluntary movements, and ensure vital functions like breathing. Changes in the structure and function of NMJs are hallmarks of numerous pathological conditions that affect muscle function including sarcopenia, the age-related loss of muscle mass and function. However, the molecular mechanisms leading to the morphological and functional perturbations in the pre- and post-synaptic compartments of the NMJ remain poorly understood. Here, we discuss the role of the metabolic pathway associated to the kinase TOR (Target of Rapamycin) in the development, maintenance and alterations of the NMJ. This is of particular interest as the TOR pathway has been implicated in aging, but its role at the NMJ is still ill-defined. We highlight the respective functions of the two TOR-associated complexes, TORC1 and TORC2, and discuss the role of localized protein synthesis and autophagy regulation in motor neuron terminals and sub-synaptic regions of muscle fibers and their possible effects on NMJ maintenance.
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Affiliation(s)
- Perrine Castets
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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21
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Gereli A, Uslu S, Okur B, Ulku TK, Kocaoğlu B, Yoo YS. Effect of suprascapular nerve injury on rotator cuff enthesis. J Shoulder Elbow Surg 2020; 29:1584-1589. [PMID: 32199756 DOI: 10.1016/j.jse.2019.12.028] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Revised: 12/17/2019] [Accepted: 12/21/2019] [Indexed: 02/01/2023]
Abstract
BACKGROUND Numerous reports have shown that retracted rotator cuff tears may cause suprascapular nerve injury, and nerve injury causes atrophy and fat accumulation in the rotator cuff muscles. However, the effect of suprascapular nerve injury on rotator cuff enthesis has not been directly defined. This study aimed to investigate the effect of suprascapular nerve injury on rotator cuff enthesis. METHODS Twenty-four Wistar albino rats underwent bilateral transection of the suprascapular nerve. Additional 6 rats were used as the sham group. Bilateral supraspinatus and infraspinatus entheses were examined after 1, 4, 8, and 12 weeks of nerve transection. Histomorphometric analyses were performed for each zone of enthesis. RESULTS Compared with normal enthesis, significant and consistent decrease in cellularity were observed in the tendon and bone at all time points (P < .001). Collagen bundle diameter in the tendon also decreased in a similar manner (P < .001). Apart from the tendon and bone zones, fibrocartilage and calcified fibrocartilage zones showed similar response, and significant decrease in cellularity was observed 8 weeks after nerve transection (P < .001). CONCLUSION This study identifies suprascapular nerve injury as an underlying mechanism leading to compromise of the rotator cuff enthesis structure. Suprascapular nerve injury may be considered as an etiologic factor for the impaired healing after repair of a massive tear.
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Affiliation(s)
- Arel Gereli
- Department of Orthopedic Surgery, Acibadem University Faculty of Medicine, Istanbul, Turkey.
| | - Serap Uslu
- Department of Histology and Embryology, Istanbul Medeniyet University, Istanbul, Turkey
| | - Beril Okur
- Acibadem University Faculty of Medicine, Istanbul, Turkey
| | - Tekin Kerem Ulku
- Department of Orthopedic Surgery, Acibadem University Faculty of Medicine, Istanbul, Turkey
| | - Barış Kocaoğlu
- Department of Orthopedic Surgery, Acibadem University Faculty of Medicine, Istanbul, Turkey
| | - Yon-Sik Yoo
- Department of Orthopedic Surgery, Hallym University Medical College, Hwaseong, Republic of Korea
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22
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Shenkman BS. How Postural Muscle Senses Disuse? Early Signs and Signals. Int J Mol Sci 2020; 21:E5037. [PMID: 32708817 PMCID: PMC7404025 DOI: 10.3390/ijms21145037] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 07/14/2020] [Accepted: 07/15/2020] [Indexed: 12/11/2022] Open
Abstract
A mammalian soleus muscle along with other "axial" muscles ensures the stability of the body under the Earth's gravity. In rat experiments with hindlimb suspension, zero-gravity parabolic flights as well as in human dry immersion studies, a dramatic decrease in the electromyographic (EMG) activity of the soleus muscle has been repeatedly shown. Most of the motor units of the soleus muscle convert from a state of activity to a state of rest which is longer than under natural conditions. And the state of rest gradually converts to the state of disuse. This review addresses a number of metabolic events that characterize the earliest stage of the cessation of the soleus muscle contractile activity. One to three days of mechanical unloading are accompanied by energy-dependent dephosphorylation of AMPK, accumulation of the reactive oxygen species, as well as accumulation of resting myoplasmic calcium. In this transition period, a rapid rearrangement of the various signaling pathways occurs, which, primarily, results in a decrease in the rate of protein synthesis (primarily via inhibition of ribosomal biogenesis and activation of endogenous inhibitors of mRNA translation, such as GSK3β) and an increase in proteolysis (via upregulation of muscle-specific E3-ubiquitin ligases).
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Affiliation(s)
- Boris S Shenkman
- Myology Laboratory, Institute of Biomedical Problems RAS, 123007 Moscow, Russia
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23
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Vainshtein A, Sandri M. Signaling Pathways That Control Muscle Mass. Int J Mol Sci 2020; 21:ijms21134759. [PMID: 32635462 PMCID: PMC7369702 DOI: 10.3390/ijms21134759] [Citation(s) in RCA: 94] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 06/23/2020] [Accepted: 07/01/2020] [Indexed: 12/12/2022] Open
Abstract
The loss of skeletal muscle mass under a wide range of acute and chronic maladies is associated with poor prognosis, reduced quality of life, and increased mortality. Decades of research indicate the importance of skeletal muscle for whole body metabolism, glucose homeostasis, as well as overall health and wellbeing. This tissue’s remarkable ability to rapidly and effectively adapt to changing environmental cues is a double-edged sword. Physiological adaptations that are beneficial throughout life become maladaptive during atrophic conditions. The atrophic program can be activated by mechanical, oxidative, and energetic distress, and is influenced by the availability of nutrients, growth factors, and cytokines. Largely governed by a transcription-dependent mechanism, this program impinges on multiple protein networks including various organelles as well as biosynthetic and quality control systems. Although modulating muscle function to prevent and treat disease is an enticing concept that has intrigued research teams for decades, a lack of thorough understanding of the molecular mechanisms and signaling pathways that control muscle mass, in addition to poor transferability of findings from rodents to humans, has obstructed efforts to develop effective treatments. Here, we review the progress made in unraveling the molecular mechanisms responsible for the regulation of muscle mass, as this continues to be an intensive area of research.
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Affiliation(s)
| | - Marco Sandri
- Veneto Institute of Molecular Medicine, via Orus 2, 35129 Padua, Italy
- Department of Biomedical Science, University of Padua, via G. Colombo 3, 35100 Padua, Italy
- Myology Center, University of Padua, via G. Colombo 3, 35100 Padova, Italy
- Department of Medicine, McGill University, Montreal, QC H3A 0G4, Canada
- Correspondence:
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Marmolejo-Martínez-Artesero S, Romeo-Guitart D, Mañas-García L, Barreiro E, Casas C. NeuroHeal Reduces Muscle Atrophy and Modulates Associated Autophagy. Cells 2020; 9:cells9071575. [PMID: 32605216 PMCID: PMC7408527 DOI: 10.3390/cells9071575] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/23/2020] [Accepted: 06/24/2020] [Indexed: 12/19/2022] Open
Abstract
Muscle wasting is an unmet medical need which leads to a reduction of myofiber diameter and a negative impact on the functional performance of daily activities. We previously found that a new neuroprotective drug called NeuroHeal reduced muscle atrophy produced by transient denervation. Aiming to decipher whether NeuroHeal has a direct role in muscle biology, we used herein different models of muscle atrophy: one caused by chronic denervation, another caused by hindlimb immobilization, and lastly, an in vitro model of myotube atrophy with Tumor Necrosis Factor-α (TNFα). In all these models, we observed that NeuroHeal reduced muscle atrophy and that SIRT1 activation seems to be required for that. The treatment downregulated some critical markers of protein degradation: Muscle Ring Finger 1 (MuRF1), K48 poly-Ub chains, and p62/SQSTM1. Moreover, it seems to restore the autophagy flux associated with denervation. Hence, we envisage a prospective use of NeuroHeal at clinics for different myopathies.
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Affiliation(s)
- Sara Marmolejo-Martínez-Artesero
- Institut de Neurociències (INc) and Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona (UAB), Bellaterra, 08193 Barcelona, Spain;
| | - David Romeo-Guitart
- Institut de Neurociències (INc) and Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona (UAB), Bellaterra, 08193 Barcelona, Spain;
- Correspondence: (D.R.-G.); (C.C.); Tel.: +33-0140615357 (D.R.-G.); +34-935811324 (C.C.)
| | - Laura Mañas-García
- Pulmonology Department-Muscle Wasting and Cachexia in Chronic Respiratory Diseases and Lung Cancer Research Group, IMIM-Hospital del Mar, Parc de Salut Mar, Health and Experimental Sciences Department (CEXS), Universitat Pompeu Fabra (UPF), Barcelona Biomedical Research Park (PRBB), 08003 Barcelona, Spain; (L.M.-G.); (E.B.)
| | - Esther Barreiro
- Pulmonology Department-Muscle Wasting and Cachexia in Chronic Respiratory Diseases and Lung Cancer Research Group, IMIM-Hospital del Mar, Parc de Salut Mar, Health and Experimental Sciences Department (CEXS), Universitat Pompeu Fabra (UPF), Barcelona Biomedical Research Park (PRBB), 08003 Barcelona, Spain; (L.M.-G.); (E.B.)
- Centro de Investigación en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos III (ISCIII), 08003 Barcelona, Spain
| | - Caty Casas
- Institut de Neurociències (INc) and Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona (UAB), Bellaterra, 08193 Barcelona, Spain;
- Correspondence: (D.R.-G.); (C.C.); Tel.: +33-0140615357 (D.R.-G.); +34-935811324 (C.C.)
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25
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Roque W, Boni A, Martinez-Manzano J, Romero F. A Tale of Two Proteolytic Machines: Matrix Metalloproteinases and the Ubiquitin-Proteasome System in Pulmonary Fibrosis. Int J Mol Sci 2020; 21:ijms21113878. [PMID: 32485920 PMCID: PMC7312171 DOI: 10.3390/ijms21113878] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 05/21/2020] [Accepted: 05/26/2020] [Indexed: 01/19/2023] Open
Abstract
Pulmonary fibrosis is a chronic and progressive lung disease characterized by the activation of fibroblasts and the irreversible deposition of connective tissue matrices that leads to altered pulmonary architecture and physiology. Multiple factors have been implicated in the pathogenesis of lung fibrosis, including genetic and environmental factors that cause abnormal activation of alveolar epithelial cells, leading to the development of complex profibrotic cascade activation and extracellular matrix (ECM) deposition. One class of proteinases that is thought to be important in the regulation of the ECM are the matrix metalloproteinases (MMPs). MMPs can be up- and down- regulated in idiopathic pulmonary fibrosis (IPF) lungs and their role depends upon their location and function. Furthermore, alterations in the ubiquitin-proteosome system (UPS), a major intracellular protein degradation complex, have been described in aging and IPF lungs. UPS alterations could potentially lead to the abnormal accumulation and deposition of ECM. A better understanding of the specific roles MMPs and UPS play in the pathophysiology of pulmonary fibrosis could potentially drive to the development of novel biomarkers that can be as diagnostic and therapeutic targets. In this review, we describe how MMPs and UPS alter ECM composition in IPF lungs and mouse models of pulmonary fibrosis, thereby influencing the alveolar epithelial and mesenchymal cell behavior. Finally, we discuss recent findings that associate MMPs and UPS interplay with the development of pulmonary fibrosis.
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Affiliation(s)
- Willy Roque
- Department of Medicine, Rutgers—New Jersey Medical School, 185 S Orange Ave, Newark, NJ 07103, USA; (W.R.); (A.B.)
| | - Alexandra Boni
- Department of Medicine, Rutgers—New Jersey Medical School, 185 S Orange Ave, Newark, NJ 07103, USA; (W.R.); (A.B.)
| | - Jose Martinez-Manzano
- Brigham and Women’s Hospital—Pulmonary and Critical Care Medicine, Boston, MA 02115, USA;
| | - Freddy Romero
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care and the Center for Translational Medicine, The Jane & Leonard Korman Respiratory Institute, Philadelphia, PA 19107, USA
- Correspondence:
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26
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Yamada T, Ashida Y, Tatebayashi D, Abe M, Himori K. Cancer Cachexia Induces Preferential Skeletal Muscle Myosin Loss When Combined With Denervation. Front Physiol 2020; 11:445. [PMID: 32425814 PMCID: PMC7212425 DOI: 10.3389/fphys.2020.00445] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 04/09/2020] [Indexed: 12/24/2022] Open
Abstract
Patients with cancer cachexia (CCX) suffer from muscle wasting, which is often but not always accompanied by selective loss of myosin. Here we examined the effects of CCX on muscle mass and myosin heavy chain (MyHC) expression in denervated (DEN) muscles, especially focusing on the protein synthesis and degradation pathways. Male CD2F1 mice were randomly divided into control (CNT) and CCX groups and their left sciatic nerve was transected. CCX was induced by an intraperitoneal injection of colon 26 cells. After 14 days, the serum concentration of IL-6 and corticosteroid was higher in CCX mice than in CNT mice. The combination of CCX with DEN (CCX + DEN) resulted in a marked reduction of the gastrocnemius muscle weight (−69%) that was significantly lower than DEN (−53%) or CCX (−36%) alone. CCX had no effect on MyHC content, but it elicited a preferential MyHC loss when combined with DEN. The expression levels of autophagy markers cathepsin D and LC3BII/I ratio were markedly higher in the CCX + DEN group than in the CNT + DEN and the CCX groups. Paradoxically, there was an increase in protein synthesis rate and phosphorylation levels of p70S6K and rpS6, markers of mTORC1 signaling, in the CNT + DEN group, and these molecular alterations were inhibited in the CCX + DEN group. Our data indicate that CCX aggravates muscle atrophy in DEN muscles by inducing seletive loss of myosin, which involves inactivity dependent mechanisms that is likely to be a consequence of increased autophagy-mediated protein breakdown coupled with impaired protein synthesis.
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Affiliation(s)
- Takashi Yamada
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan
| | - Yuki Ashida
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan
| | - Daisuke Tatebayashi
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan
| | - Masami Abe
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan
| | - Koichi Himori
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan
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27
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Nikolaou S, Cramer AA, Hu L, Goh Q, Millay DP, Cornwall R. Proteasome inhibition preserves longitudinal growth of denervated muscle and prevents neonatal neuromuscular contractures. JCI Insight 2019; 4:128454. [PMID: 31661460 DOI: 10.1172/jci.insight.128454] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 10/16/2019] [Indexed: 12/14/2022] Open
Abstract
Muscle contractures are a prominent and disabling feature of many neuromuscular disorders, including the 2 most common forms of childhood neurologic dysfunction: neonatal brachial plexus injury (NBPI) and cerebral palsy. There are currently no treatment strategies to directly alter the contracture pathology, as the pathogenesis of these contractures is unknown. We previously showed in a mouse model of NBPI that contractures result from impaired longitudinal muscle growth. Current presumed explanations for growth impairment in contractures focus on the dysregulation of muscle stem cells, which differentiate and fuse to existing myofibers during growth, as this process has classically been thought to control muscle growth during the neonatal period. Here, we demonstrate in a mouse model of NBPI that denervation does not prevent myonuclear accretion and that reduction in myonuclear number has no effect on functional muscle length or contracture development, providing definitive evidence that altered myonuclear accretion is not a driver of neuromuscular contractures. In contrast, we observed elevated levels of protein degradation in NBPI muscle, and we demonstrate that contractures can be pharmacologically prevented with the proteasome inhibitor bortezomib. These studies provide what we believe is the first strategy to prevent neuromuscular contractures by correcting the underlying deficit in longitudinal muscle growth.
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Affiliation(s)
| | - Alyssa Aw Cramer
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | | | | | - Douglas P Millay
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Roger Cornwall
- Division of Orthopaedic Surgery, and.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.,Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Department of Orthopaedic Surgery, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
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28
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Adegoke OAJ, Beatty BE, Kimball SR, Wing SS. Interactions of the super complexes: When mTORC1 meets the proteasome. Int J Biochem Cell Biol 2019; 117:105638. [PMID: 31678320 PMCID: PMC6910232 DOI: 10.1016/j.biocel.2019.105638] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 10/18/2019] [Accepted: 10/20/2019] [Indexed: 12/30/2022]
Abstract
Homeostatic regulation of energy and metabolic status requires that anabolic and catabolic signaling pathways be precisely regulated and coordinated. Mammalian/mechanistic target of rapamycin complex 1 (mTORC1) is a mega protein complex that promotes energy-consuming anabolic processes of protein and nucleic acid synthesis as well lipogenesis in times of energy and nutrient abundance. However, it is best characterized as the regulator of steps leading to protein synthesis. The ubiquitin-proteasome proteolytic system (UPS) is a major intracellular proteolytic system whose activity is increased during periods of nutrient scarcity and in muscle wasting conditions such as cachexia. Recent studies have examined the impact of mTORC1 on levels and functions of the 26S proteasome, the mega protease complex of the UPS. Here we first briefly review current understanding of the regulation of mTORC1, the UPS, and the 26S proteasome complex. We then review evidence of the effect of each complex on the abundance and functions of the other. Given the fact that drugs that inhibit either complex are either in clinical trials or are approved for treatment of cancer, a muscle wasting condition, we identify studying the effect of combinatory mTORC1-proteasome inhibition on skeletal muscle mass and health as a critical area requiring investigation.
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Affiliation(s)
- Olasunkanmi A J Adegoke
- School of Kinesiology and Health Science, and Muscle Health Research Centre, York University, 4700 Keele Street, Toronto, Ontario, M3J 1P3 Canada.
| | - Brendan E Beatty
- School of Kinesiology and Health Science, and Muscle Health Research Centre, York University, 4700 Keele Street, Toronto, Ontario, M3J 1P3 Canada
| | - Scot R Kimball
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Simon S Wing
- Department of Medicine, McGill University and the Research Institute of the McGill University Health Centre, the Montreal Diabetes Research Centre, Montréal, Quebec, H4A 3J1. Canada
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29
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Ebstein F, Poli Harlowe MC, Studencka-Turski M, Krüger E. Contribution of the Unfolded Protein Response (UPR) to the Pathogenesis of Proteasome-Associated Autoinflammatory Syndromes (PRAAS). Front Immunol 2019; 10:2756. [PMID: 31827472 PMCID: PMC6890838 DOI: 10.3389/fimmu.2019.02756] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 11/11/2019] [Indexed: 12/13/2022] Open
Abstract
Type I interferonopathies cover a phenotypically heterogeneous group of rare genetic diseases including the recently described proteasome-associated autoinflammatory syndromes (PRAAS). By definition, PRAAS are caused by inherited and/or de novo loss-of-function mutations in genes encoding proteasome subunits such as PSMB8, PSMB9, PSMB7, PSMA3, or proteasome assembly factors including POMP and PSMG2, respectively. Disruption of any of these subunits results in perturbed intracellular protein homeostasis including accumulation of ubiquitinated proteins which is accompanied by a type I interferon (IFN) signature. The observation that, similarly to pathogens, proteasome dysfunctions are potent type I IFN inducers is quite unexpected and, up to now, the underlying molecular mechanisms of this process remain largely unknown. One promising candidate for triggering type I IFN under sterile conditions is the unfolded protein response (UPR) which is typically initiated in response to an accumulation of unfolded and/or misfolded proteins in the endoplasmic reticulum (ER) (also referred to as ER stress). The recent observation that the UPR is engaged in subjects carrying POMP mutations strongly suggests its possible implication in the cause-and-effect relationship between proteasome impairment and interferonopathy onset. The purpose of this present review is therefore to discuss the possible role of the UPR in the pathogenesis of PRAAS. We will particularly focus on pathways initiated by the four ER-membrane proteins ATF6, PERK, IRE1-α, and TCF11/Nrf1 which undergo activation under proteasome inhibition. An overview of the current understanding of the mechanisms and potential cross-talk between the UPR and inflammatory signaling casacades is provided to convey a more integrated picture of the pathophysiology of PRAAS and shed light on potential biomarkers and therapeutic targets.
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Affiliation(s)
- Frédéric Ebstein
- Institut für Medizinische Biochemie und Molekularbiologie, Universitätsmedizin Greifswald, Greifswald, Germany
| | - María Cecilia Poli Harlowe
- Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago, Chile.,Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - Maja Studencka-Turski
- Institut für Medizinische Biochemie und Molekularbiologie, Universitätsmedizin Greifswald, Greifswald, Germany
| | - Elke Krüger
- Institut für Medizinische Biochemie und Molekularbiologie, Universitätsmedizin Greifswald, Greifswald, Germany
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30
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Yujra VQ, Moreira Antunes HK, Mônico-Neto M, Quintana HT, de Oliveira F, Galvani MG, Lee KS, Oshima CTF, Ribeiro DA. Paradoxical sleep deprivation induces differential biological response in rat masticatory muscles: Inflammation, autophagy and myogenesis. J Oral Rehabil 2019; 47:289-300. [PMID: 31701551 DOI: 10.1111/joor.12904] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 10/03/2019] [Accepted: 10/14/2019] [Indexed: 12/17/2022]
Abstract
BACKGROUND The aim of this study was to evaluate whether sleep deprivation (SD) induces inflammation, autophagy and myogenesis in the following masticatory muscles: masseter and temporal. METHODS In this study, 18 animals were randomly distributed into three groups: control group (CTL, n = 6), SD for 96 hours (SD96, n = 6), and SD for 96 hours and more 96 hours of sleep recovery (SD96 + R, n = 6). RESULTS In the histopathological analysis, SD 96 was able to induce inflammation in masseter and temporal. Nevertheless, the lack of inflammatory process was evidenced to the masseter in the group SD96 + R. Upregulation of TNF-alpha production was detected in the SD96 group, while SD96 + R decreased TNF immunoexpression for both skeletal muscles evaluated. MyoD and myogenin increased in rats submitted to SD96. By contrast, the levels of MyoD decreased in the group SD96 + R. Myogenin pointed out high immunoexpression in SD96 + R groups. In temporal, pAkt decreased in animals submitted to SD96, but it increased in the group SD96 + R. The levels of LC3 protein increased in both skeletal muscles studied, and masseter decreased LC3 protein expression in the SD96 + R. CONCLUSION In summary, our results demonstrate that SD is able to induce inflammation, atrophy and myogenesis in rat masticatory muscles, being more intense in temporal when compared to masseter.
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Affiliation(s)
- Veronica Quispe Yujra
- Department of Pathology, Federal University of São Paulo, UNIFESP, São Paulo, Brazil
| | | | - Marcos Mônico-Neto
- Department of Biosciences, Federal University of São Paulo, UNIFESP, Santos, Brazil
| | | | - Flavia de Oliveira
- Department of Biosciences, Federal University of São Paulo, UNIFESP, Santos, Brazil
| | - Marina Gomes Galvani
- Department of Biosciences, Federal University of São Paulo, UNIFESP, Santos, Brazil
| | - Kil Sun Lee
- Department of Biochemistry, Federal University of São Paulo, UNIFESP, São Paulo, Brazil
| | | | - Daniel Araki Ribeiro
- Department of Biosciences, Federal University of São Paulo, UNIFESP, Santos, Brazil
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31
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Odeh M, Tamir‐Livne Y, Haas T, Bengal E. P38α MAPK coordinates the activities of several metabolic pathways that together induce atrophy of denervated muscles. FEBS J 2019; 287:73-93. [DOI: 10.1111/febs.15070] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 05/30/2019] [Accepted: 09/18/2019] [Indexed: 12/11/2022]
Affiliation(s)
- Maali Odeh
- Department of Biochemistry Rappaport Faculty of Medicine Technion‐Israel Institute of Technology Haifa Israel
| | - Yael Tamir‐Livne
- Department of Biochemistry Rappaport Faculty of Medicine Technion‐Israel Institute of Technology Haifa Israel
| | - Tali Haas
- Pre‐Clinical Research Authority Technion‐Israel Institute of Technology Haifa Israel
| | - Eyal Bengal
- Department of Biochemistry Rappaport Faculty of Medicine Technion‐Israel Institute of Technology Haifa Israel
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32
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Yamada T, Ashida Y, Tatebayashi D, Himori K. Myofibrillar function differs markedly between denervated and dexamethasone-treated rat skeletal muscles: Role of mechanical load. PLoS One 2019; 14:e0223551. [PMID: 31596883 PMCID: PMC6785062 DOI: 10.1371/journal.pone.0223551] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 09/24/2019] [Indexed: 01/24/2023] Open
Abstract
Although there is good evidence to indicate a major role of intrinsic impairment of the contractile apparatus in muscle weakness seen in several pathophysiological conditions, the factors responsible for control of myofibrillar function are not fully understood. To investigate the role of mechanical load in myofibrillar function, we compared the skinned fiber force between denervated (DEN) and dexamethasone-treated (DEX) rat skeletal muscles with or without neuromuscular electrical stimulation (ES) training. DEN and DEX were induced by cutting the sciatic nerve and daily injection of dexamethasone (5 mg/kg/day) for 7 days, respectively. For ES training, plantarflexor muscles were electrically stimulated to produce four sets of five isometric contractions each day. In situ maximum torque was markedly depressed in the DEN muscles compared to the DEX muscles (-74% vs. -10%), whereas there was not much difference in the degree of atrophy in gastrocnemius muscles between DEN and DEX groups (-24% vs. -17%). Similar results were obtained in the skinned fiber preparation, with a greater reduction in maximum Ca2+-activated force in the DEN than in the DEX group (-53% vs. -16%). Moreover, there was a parallel decline in myosin heavy chain (MyHC) and actin content per muscle volume in DEN muscles, but not in DEX muscles, which was associated with upregulation of NADPH oxidase (NOX) 2, neuronal nitric oxide synthase (nNOS), and endothelial NOS expression, translocation of nNOS from the membrane to the cytosol, and augmentation of mRNA levels of muscle RING finger protein 1 (MuRF-1) and atrogin-1. Importantly, mechanical load evoked by ES protects against DEN- and DEX-induced myofibrillar dysfunction and these molecular alterations. Our findings provide novel insights regarding the difference in intrinsic contractile properties between DEN and DEX and suggest an important role of mechanical load in preserving myofibrillar function in skeletal muscle.
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Affiliation(s)
- Takashi Yamada
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan
- * E-mail:
| | - Yuki Ashida
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan
- Research Fellow of Japan Society for the Promotion of Science, Tokyo, Japan
| | - Daisuke Tatebayashi
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan
| | - Koichi Himori
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan
- Research Fellow of Japan Society for the Promotion of Science, Tokyo, Japan
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33
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Elevated p70S6K phosphorylation in rat soleus muscle during the early stage of unloading: Causes and consequences. Arch Biochem Biophys 2019; 674:108105. [PMID: 31518555 DOI: 10.1016/j.abb.2019.108105] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 09/03/2019] [Accepted: 09/10/2019] [Indexed: 12/31/2022]
Abstract
Currently, there is a lack of investigation into the initial signaling events underlying the development of disuse muscle atrophy. The study was aimed to (i) identify an assumed relationship between AMPK dephosphorylation and p70S6K hyperphosphorylation in the initial period of hindlimb unloading (HS), and (ii) assess the signaling consequences of p70S6K hyperphosphorylation following 24-h HS. For experiment 1, rats were treated with AMPK activator (AICAR) for 6 d before HS as well as during 24-h HS. For experiment 2, rats were treated with mTORC1 inhibitor rapamycin during 24-h HS. The key signaling markers implicated in protein turnover were assessed using WB and RT-PCR. One-day HS resulted in a significant upregulation of MuRF-1 and MAFbx expression, increase in p70S6K (Thr389) and IRS-1 (Ser639) phosphorylation and a significant decrease in phosphorylated AMPK, AKT, FOXO3, total IRS-1 content, and HDAC5 nuclear content. AMPK and p70S6K phosphorylation did not differ from control in AICAR-treated unloaded rats. Rapamycin treatment during unloading abolished p70S6K and E3 ligases upregulation and increased HDAC5 nuclear accumulation. The results of the study suggest that mTORC-1/p70S6K signaling pathway in rat soleus muscle is activated following 24-h mechanical unloading. This activation is facilitated by a decrease in AMPK phosphorylation. Increased p70S6K activity at the initial stage of hindlimb unloading could lead to the upregulation of E3 ligases MAFbx/atrogin-1 and MuRF-1 via nuclear export of HDAC5.
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34
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mTORC1 and PKB/Akt control the muscle response to denervation by regulating autophagy and HDAC4. Nat Commun 2019; 10:3187. [PMID: 31320633 PMCID: PMC6639401 DOI: 10.1038/s41467-019-11227-4] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 07/02/2019] [Indexed: 12/13/2022] Open
Abstract
Loss of innervation of skeletal muscle is a determinant event in several muscle diseases. Although several effectors have been identified, the pathways controlling the integrated muscle response to denervation remain largely unknown. Here, we demonstrate that PKB/Akt and mTORC1 play important roles in regulating muscle homeostasis and maintaining neuromuscular endplates after nerve injury. To allow dynamic changes in autophagy, mTORC1 activation must be tightly balanced following denervation. Acutely activating or inhibiting mTORC1 impairs autophagy regulation and alters homeostasis in denervated muscle. Importantly, PKB/Akt inhibition, conferred by sustained mTORC1 activation, abrogates denervation-induced synaptic remodeling and causes neuromuscular endplate degeneration. We establish that PKB/Akt activation promotes the nuclear import of HDAC4 and is thereby required for epigenetic changes and synaptic gene up-regulation upon denervation. Hence, our study unveils yet-unknown functions of PKB/Akt-mTORC1 signaling in the muscle response to nerve injury, with important implications for neuromuscular integrity in various pathological conditions. Denervation leads to muscle atrophy and neuromuscular endplate remodeling. Here, the authors show that a balanced activation of mTORC1 contributes to the dynamic regulation of autophagic flux in denervated muscle and that activation of PKB/Akt promotes the nuclear import of HDAC4, which is essential for endplate maintenance upon nerve injury
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35
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Møller AB, Vendelbo MH, Schjerling P, Couppé C, Møller N, Kjær M, Hansen M, Jessen N. Immobilization Decreases FOXO3a Phosphorylation and Increases Autophagy-Related Gene and Protein Expression in Human Skeletal Muscle. Front Physiol 2019; 10:736. [PMID: 31258486 PMCID: PMC6587099 DOI: 10.3389/fphys.2019.00736] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 05/27/2019] [Indexed: 01/07/2023] Open
Abstract
Immobilization of the lower limbs promotes a catabolic state that reduces muscle mass, whereas physical training promotes an anabolic state that increases muscle mass. Understanding the molecular mechanisms underlying this is of clinical interest, as loss of muscle mass is a major complication to critical illness in humans. To determine the molecular regulation of protein synthesis and degradation during muscle loss and hypertrophy, we examined skeletal muscle biopsies from healthy human subjects after 2 weeks unilateral immobilization of a lower limb and during 6 weeks of physical rehabilitation. We have previously shown that cross-sectional area of the knee muscle-extensors decreased by ∼10% during immobilization and was completely restored during rehabilitation. Here we provide novel data to suggest that autophagy is an important underlying mechanism involved in regulation of muscle mass. Protein expression of MuRF1 and ATROGIN-1 did not change during the study, indicating that the recruitment of substrates to the proteasomes was unaltered. Phosphorylation of mTORat Ser2448 did not change during the study, and neither did phosphorylation of the mTORC1 substrates 4EBP1 Thr37/46 and p70S6K Thr389, suggesting that this pathway does not suppress protein synthesis during muscle wasting. Protein levels of p62 and ULK1 increased during immobilization and returned to baseline levels during rehabilitation. Same pattern was observed for FOXO3a phosphorylation at Ser318/321, suggesting transcriptional activation during immobilization and inactivation during rehabilitation. To investigate this further, we analyzed mRNA expression of seven autophagy-related genes controlled by FOXO3a. Five of these (p62, LC3B, BECLIN-1, ATG12, and BNIP3) increased during immobilization and returned to baseline during rehabilitation. In conclusion, immobilization of a lower limb increases autophagy-related gene and protein expression in human skeletal muscle in a pattern that mirrors FOXO3a phosphorylation. These findings could imply that FOXO3a dependent transcriptional regulation of autophagy is involved in the regulation of muscle mass in humans.
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Affiliation(s)
- Andreas Buch Møller
- Research Laboratory for Biochemical Pathology, Institute for Clinical Medicine, Aarhus University, Aarhus, Denmark.,Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus, Denmark
| | - Mikkel Holm Vendelbo
- Department of Nuclear Medicine & PET-Centre, Aarhus University Hospital, Aarhus, Denmark
| | - Peter Schjerling
- Department of Orthopaedic Surgery M, Bispebjerg Hospital, and Center for Healthy Aging, Faculty of Health and Medical Sciences, Institute of Sports Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Christian Couppé
- Department of Orthopaedic Surgery M, Bispebjerg Hospital, and Center for Healthy Aging, Faculty of Health and Medical Sciences, Institute of Sports Medicine, University of Copenhagen, Copenhagen, Denmark.,Musculoskeletal Rehabilitation Research Unit, Department of Physical Therapy, Bispebjerg Hospital, Copenhagen, Denmark
| | - Niels Møller
- Medical Research Laboratory, Institute for Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Michael Kjær
- Department of Orthopaedic Surgery M, Bispebjerg Hospital, and Center for Healthy Aging, Faculty of Health and Medical Sciences, Institute of Sports Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Mette Hansen
- Department of Orthopaedic Surgery M, Bispebjerg Hospital, and Center for Healthy Aging, Faculty of Health and Medical Sciences, Institute of Sports Medicine, University of Copenhagen, Copenhagen, Denmark.,Section of Sports Science, Department of Public Health, Aarhus University, Aarhus, Denmark
| | - Niels Jessen
- Research Laboratory for Biochemical Pathology, Institute for Clinical Medicine, Aarhus University, Aarhus, Denmark.,Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus, Denmark
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36
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Bouchè M, Lozanoska-Ochser B, Proietti D, Madaro L. Do neurogenic and cancer-induced muscle atrophy follow common or divergent paths? Eur J Transl Myol 2018; 28:7931. [PMID: 30662704 PMCID: PMC6317130 DOI: 10.4081/ejtm.2018.7931] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 12/05/2018] [Indexed: 11/22/2022] Open
Abstract
Skeletal muscle is a dynamic tissue capable of responding to a large variety of physiological stimuli by adjusting muscle fiber size, metabolism and function. However, in pathological conditions such as cancer and neural disorders, this finely regulated homeostasis is impaired leading to severe muscle wasting, reduced muscle fiber size (atrophy), and impaired function. These disease features develop due to enhanced protein breakdown, which relies on two major degradation systems: the ubiquitin-proteasome and the autophagy-lysosome. These systems are independently regulated by different signalling pathways, which in physiological conditions, determine protein and organelle turnover. However, alterations in one or both systems, as it happens in several disorders, leads to enhanced protein breakdown and muscle atrophy. Although this is a common feature in the different types of muscle atrophy, the relative contribution of each of these systems is still under debate. Here, we will briefly describe the regulation and the activity of the ubiquitin-proteasome and the autophagy-lysosome systems during muscle wasting. We will then discuss what we know regarding how these pathways are involved in cancer induced and in neurogenic muscle atrophy, highlighting common and divergent paths. It is now clear that there is no one unifying common mechanism that can be applied to all models of muscle loss. Detailed understanding of the pathways and proteolysis mechanisms involved in each model will hopefully help the development of drugs to counteract muscle wasting in specific conditions.
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Affiliation(s)
- Marina Bouchè
- DAHFMO, Unit of Histology, Sapienza University of Rome, 00161 Rome, Italy.,Interuniversity Institute of Myology, Italy
| | | | - Daisy Proietti
- DAHFMO, Unit of Histology, Sapienza University of Rome, 00161 Rome, Italy.,IRCCS, Fondazione Santa Lucia, Rome, Italy
| | - Luca Madaro
- IRCCS, Fondazione Santa Lucia, Rome, Italy.,Interuniversity Institute of Myology, Italy
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Mirzoev TM, Shenkman BS. Regulation of Protein Synthesis in Inactivated Skeletal Muscle: Signal Inputs, Protein Kinase Cascades, and Ribosome Biogenesis. BIOCHEMISTRY (MOSCOW) 2018; 83:1299-1317. [PMID: 30482143 DOI: 10.1134/s0006297918110020] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Disuse atrophy of skeletal muscles is characterized by a significant decrease in the mass and size of muscle fibers. Disuse atrophy develops as a result of prolonged reduction in the muscle functional activity caused by bed rest, limb immobilization, and real or simulated microgravity. Disuse atrophy is associated with the downregulation of protein biosynthesis and simultaneous activation of protein degradation. This review is focused on the key molecular mechanisms regulating the rate of protein synthesis in mammalian skeletal muscles during functional unloading.
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Affiliation(s)
- T M Mirzoev
- Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, 123007, Russia.
| | - B S Shenkman
- Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, 123007, Russia
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Pigna E, Sanna K, Coletti D, Li Z, Parlakian A, Adamo S, Moresi V. Increasing autophagy does not affect neurogenic muscle atrophy. Eur J Transl Myol 2018; 28:7687. [PMID: 30344980 PMCID: PMC6176397 DOI: 10.4081/ejtm.2018.7687] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 08/11/2018] [Accepted: 08/10/2018] [Indexed: 11/23/2022] Open
Abstract
Physiological autophagy plays a crucial role in the regulation of muscle mass and metabolism, while the excessive induction or the inhibition of the autophagic flux contributes to the progression of several diseases. Autophagy can be activated by different stimuli, including cancer, exercise, caloric restriction and denervation. The latter leads to muscle atrophy through the activation of catabolic pathways, i.e. the ubiquitin-proteasome system and autophagy. However, the kinetics of autophagy activation and the upstream molecular pathways in denervated skeletal muscle have not been reported yet. In this study, we characterized the kinetics of autophagic induction, quickly triggered by denervation, and report the Akt/mTOR axis activation. Besides, with the aim to assess the relative contribution of autophagy in neurogenic muscle atrophy, we triggered autophagy with different stimuli along with denervation, and observed that four week-long autophagic induction, by either intermitted fasting or rapamycin treatment, did not significantly affect muscle mass loss. We conclude that: i) autophagy does not play a major role in inducing muscle loss following denervation; ii) nonetheless, autophagy may have a regulatory role in denervation induced muscle atrophy, since it is significantly upregulated as early as eight hours after denervation; iii) Akt/mTOR axis, AMPK and FoxO3a are activated consistently with the progression of muscle atrophy, further highlighting the complexity of the signaling response to the atrophying stimulus deriving from denervation.
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Affiliation(s)
- Eva Pigna
- Department of Anatomy, Histology, Forensic Medicine & Orthopedics, Histology & Medical Embryology Section, Sapienza University of Rome, Italy
| | - Krizia Sanna
- Department of Anatomy, Histology, Forensic Medicine & Orthopedics, Histology & Medical Embryology Section, Sapienza University of Rome, Italy
| | - Dario Coletti
- Department of Anatomy, Histology, Forensic Medicine & Orthopedics, Histology & Medical Embryology Section, Sapienza University of Rome, Italy.,Interuniversity Institute of Myology, Italy.,Sorbonne Université, CNRS UMR 8256-INSERM ERL U1164, IBPS B2A Department of Biological Adaptation and Aging, Paris, France
| | - Zhenlin Li
- Sorbonne Université, CNRS UMR 8256-INSERM ERL U1164, IBPS B2A Department of Biological Adaptation and Aging, Paris, France
| | - Ara Parlakian
- Sorbonne Université, CNRS UMR 8256-INSERM ERL U1164, IBPS B2A Department of Biological Adaptation and Aging, Paris, France
| | | | - Viviana Moresi
- Department of Anatomy, Histology, Forensic Medicine & Orthopedics, Histology & Medical Embryology Section, Sapienza University of Rome, Italy.,Interuniversity Institute of Myology, Italy
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Exercise prevents impaired autophagy and proteostasis in a model of neurogenic myopathy. Sci Rep 2018; 8:11818. [PMID: 30087400 PMCID: PMC6081439 DOI: 10.1038/s41598-018-30365-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 07/26/2018] [Indexed: 01/07/2023] Open
Abstract
Increased proteolytic activity has been widely associated with skeletal muscle atrophy. However, elevated proteolysis is also critical for the maintenance of cellular homeostasis by disposing cytotoxic proteins and non-functioning organelles. We recently demonstrated that exercise activates autophagy and re-establishes proteostasis in cardiac diseases. Here, we characterized the impact of exercise on skeletal muscle autophagy and proteostasis in a model of neurogenic myopathy induced by sciatic nerve constriction in rats. Neurogenic myopathy, characterized by progressive atrophy and impaired contractility, was paralleled by accumulation of autophagy-related markers and loss of acute responsiveness to both colchicine and chloroquine. These changes were correlated with elevated levels of damaged proteins, chaperones and pro-apoptotic markers compared to control animals. Sustained autophagy inhibition using chloroquine in rats (50 mg.kg-1.day-1) or muscle-specific deletion of Atg7 in mice was sufficient to impair muscle contractility in control but not in neurogenic myopathy, suggesting that dysfunctional autophagy is critical in skeletal muscle pathophysiology. Finally, 4 weeks of aerobic exercise training (moderate treadmill running, 5x/week, 1 h/day) prior to neurogenic myopathy improved skeletal muscle autophagic flux and proteostasis. These changes were followed by spared muscle mass and better contractility properties. Taken together, our findings suggest the potential value of exercise in maintaining skeletal muscle proteostasis and slowing down the progression of neurogenic myopathy.
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Dyar KA, Hubert MJ, Mir AA, Ciciliot S, Lutter D, Greulich F, Quagliarini F, Kleinert M, Fischer K, Eichmann TO, Wright LE, Peña Paz MI, Casarin A, Pertegato V, Romanello V, Albiero M, Mazzucco S, Rizzuto R, Salviati L, Biolo G, Blaauw B, Schiaffino S, Uhlenhaut NH. Transcriptional programming of lipid and amino acid metabolism by the skeletal muscle circadian clock. PLoS Biol 2018; 16:e2005886. [PMID: 30096135 PMCID: PMC6105032 DOI: 10.1371/journal.pbio.2005886] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 08/22/2018] [Accepted: 07/27/2018] [Indexed: 12/30/2022] Open
Abstract
Circadian clocks are fundamental physiological regulators of energy homeostasis, but direct transcriptional targets of the muscle clock machinery are unknown. To understand how the muscle clock directs rhythmic metabolism, we determined genome-wide binding of the master clock regulators brain and muscle ARNT-like protein 1 (BMAL1) and REV-ERBα in murine muscles. Integrating occupancy with 24-hr gene expression and metabolomics after muscle-specific loss of BMAL1 and REV-ERBα, here we unravel novel molecular mechanisms connecting muscle clock function to daily cycles of lipid and protein metabolism. Validating BMAL1 and REV-ERBα targets using luciferase assays and in vivo rescue, we demonstrate how a major role of the muscle clock is to promote diurnal cycles of neutral lipid storage while coordinately inhibiting lipid and protein catabolism prior to awakening. This occurs by BMAL1-dependent activation of Dgat2 and REV-ERBα-dependent repression of major targets involved in lipid metabolism and protein turnover (MuRF-1, Atrogin-1). Accordingly, muscle-specific loss of BMAL1 is associated with metabolic inefficiency, impaired muscle triglyceride biosynthesis, and accumulation of bioactive lipids and amino acids. Taken together, our data provide a comprehensive overview of how genomic binding of BMAL1 and REV-ERBα is related to temporal changes in gene expression and metabolite fluctuations.
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Affiliation(s)
- Kenneth Allen Dyar
- Helmholtz Diabetes Center (HMGU) and German Center for Diabetes Research (DZD), Institute for Diabetes and Obesity (IDO), Munich, Germany
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy
| | - Michaël Jean Hubert
- Helmholtz Diabetes Center (HMGU) and German Center for Diabetes Research (DZD), Institute for Diabetes and Obesity (IDO), Munich, Germany
| | - Ashfaq Ali Mir
- Helmholtz Diabetes Center (HMGU) and German Center for Diabetes Research (DZD), Institute for Diabetes and Obesity (IDO), Munich, Germany
| | | | - Dominik Lutter
- Helmholtz Diabetes Center (HMGU) and German Center for Diabetes Research (DZD), Institute for Diabetes and Obesity (IDO), Munich, Germany
| | - Franziska Greulich
- Helmholtz Diabetes Center (HMGU) and German Center for Diabetes Research (DZD), Institute for Diabetes and Obesity (IDO), Munich, Germany
| | - Fabiana Quagliarini
- Helmholtz Diabetes Center (HMGU) and German Center for Diabetes Research (DZD), Institute for Diabetes and Obesity (IDO), Munich, Germany
| | - Maximilian Kleinert
- Helmholtz Diabetes Center (HMGU) and German Center for Diabetes Research (DZD), Institute for Diabetes and Obesity (IDO), Munich, Germany
| | - Katrin Fischer
- Helmholtz Diabetes Center (HMGU) and German Center for Diabetes Research (DZD), Institute for Diabetes and Obesity (IDO), Munich, Germany
| | | | | | | | - Alberto Casarin
- Clinical Genetics Unit, Department of Woman and Child Health, University of Padova, and IRP Città della Speranza, Padova, Italy
| | - Vanessa Pertegato
- Clinical Genetics Unit, Department of Woman and Child Health, University of Padova, and IRP Città della Speranza, Padova, Italy
| | | | - Mattia Albiero
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy
| | - Sara Mazzucco
- Clinica Medica, Department of Medical Sciences, University of Trieste, Trieste, Italy
| | - Rosario Rizzuto
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Leonardo Salviati
- Clinical Genetics Unit, Department of Woman and Child Health, University of Padova, and IRP Città della Speranza, Padova, Italy
| | - Gianni Biolo
- Clinica Medica, Department of Medical Sciences, University of Trieste, Trieste, Italy
| | - Bert Blaauw
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | | | - N. Henriette Uhlenhaut
- Helmholtz Diabetes Center (HMGU) and German Center for Diabetes Research (DZD), Institute for Diabetes and Obesity (IDO), Munich, Germany
- Gene Center, Ludwig-Maximilians-Universitaet (LMU), Munich, Germany
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Distinct homeostatic modulations stabilize reduced postsynaptic receptivity in response to presynaptic DLK signaling. Nat Commun 2018; 9:1856. [PMID: 29748610 PMCID: PMC5945772 DOI: 10.1038/s41467-018-04270-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 04/16/2018] [Indexed: 11/08/2022] Open
Abstract
Synapses are constructed with the stability to last a lifetime, yet sufficiently flexible to adapt during injury. Although fundamental pathways that mediate intrinsic responses to neuronal injury have been defined, less is known about how synaptic partners adapt. We have investigated responses in the postsynaptic cell to presynaptic activation of the injury-related Dual Leucine Zipper Kinase pathway at the Drosophila neuromuscular junction. We find that the postsynaptic compartment reduces neurotransmitter receptor levels, thus depressing synaptic strength. Interestingly, this diminished state is stabilized through distinct modulations to two postsynaptic homeostatic signaling systems. First, a retrograde response normally triggered by reduced receptor levels is silenced, preventing a compensatory enhancement in presynaptic neurotransmitter release. However, when global presynaptic release is attenuated, a postsynaptic receptor scaling mechanism persists to adaptively stabilize this diminished neurotransmission state. Thus, the homeostatic set point of synaptic strength is recalibrated to a reduced state as synapses acclimate to injury.
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Lim JA, Sun B, Puertollano R, Raben N. Therapeutic Benefit of Autophagy Modulation in Pompe Disease. Mol Ther 2018; 26:1783-1796. [PMID: 29804932 DOI: 10.1016/j.ymthe.2018.04.025] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 04/25/2018] [Accepted: 04/30/2018] [Indexed: 12/11/2022] Open
Abstract
The complexity of the pathogenic cascade in lysosomal storage disorders suggests that combination therapy will be needed to target various aspects of pathogenesis. The standard of care for Pompe disease (glycogen storage disease type II), a deficiency of lysosomal acid alpha glucosidase, is enzyme replacement therapy (ERT). Many patients have poor outcomes due to limited efficacy of the drug in clearing muscle glycogen stores. The resistance to therapy is linked to massive autophagic buildup in the diseased muscle. We have explored two strategies to address the problem. Genetic suppression of autophagy in muscle of knockout mice resulted in the removal of autophagic buildup, increase in muscle force, decrease in glycogen level, and near-complete clearance of lysosomal glycogen following ERT. However, this approach leads to accumulation of ubiquitinated proteins, oxidative stress, and exacerbation of muscle atrophy. Another approach involves AAV-mediated TSC knockdown in knockout muscle leading to upregulation of mTOR, inhibition of autophagy, reversal of atrophy, and efficient cellular clearance on ERT. Importantly, this approach reveals the possibility of reversing already established autophagic buildup, rather than preventing its development.
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Affiliation(s)
- Jeong-A Lim
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD, USA; Division of Medical Genetics, Department of Pediatrics, Duke University School of Medicine, Durham, NC, USA
| | - Baodong Sun
- Division of Medical Genetics, Department of Pediatrics, Duke University School of Medicine, Durham, NC, USA
| | - Rosa Puertollano
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD, USA.
| | - Nina Raben
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD, USA.
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43
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Castets P, Frank S, Sinnreich M, Rüegg MA. "Get the Balance Right": Pathological Significance of Autophagy Perturbation in Neuromuscular Disorders. J Neuromuscul Dis 2018; 3:127-155. [PMID: 27854220 PMCID: PMC5271579 DOI: 10.3233/jnd-160153] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Recent research has revealed that autophagy, a major catabolic process in cells, is dysregulated in several neuromuscular diseases and contributes to the muscle wasting caused by non-muscle disorders (e.g. cancer cachexia) or during aging (i.e. sarcopenia). From there, the idea arose to interfere with autophagy or manipulate its regulatory signalling to help restore muscle homeostasis and attenuate disease progression. The major difficulty for the development of therapeutic strategies is to restore a balanced autophagic flux, due to the dynamic nature of autophagy. Thus, it is essential to better understand the mechanisms and identify the signalling pathways at play in the control of autophagy in skeletal muscle. A comprehensive analysis of the autophagic flux and of the causes of its dysregulation is required to assess the pathogenic role of autophagy in diseased muscle. Furthermore, it is essential that experiments distinguish between primary dysregulation of autophagy (prior to disease onset) and impairments as a consequence of the pathology. Of note, in most muscle disorders, autophagy perturbation is not caused by genetic modification of an autophagy-related protein, but rather through indirect alteration of regulatory signalling or lysosomal function. In this review, we will present the mechanisms involved in autophagy, and those ensuring its tight regulation in skeletal muscle. We will then discuss as to how autophagy dysregulation contributes to the pathogenesis of neuromuscular disorders and possible ways to interfere with this process to limit disease progression.
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Affiliation(s)
| | - Stephan Frank
- Institute of Pathology, Division of Neuropathology Basel University Hospital, Basel, Switzerland
| | - Michael Sinnreich
- Neuromuscular Research Center, Departments of Neurology and Biomedicine, Pharmazentrum, Basel, Switzerland
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44
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Gan L, Liu Z, Luo D, Ren Q, Wu H, Li C, Sun C. Reduced Endoplasmic Reticulum Stress-Mediated Autophagy Is Required for Leptin Alleviating Inflammation in Adipose Tissue. Front Immunol 2017; 8:1507. [PMID: 29250056 PMCID: PMC5715390 DOI: 10.3389/fimmu.2017.01507] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Accepted: 10/25/2017] [Indexed: 12/15/2022] Open
Abstract
Leptin is an adipocyte-derived hormone and maintains adipose function under challenged conditions. Autophagy is also essential to maintain cellular homeostasis and regulate characteristics of adipose tissue. However, the effects of leptin on autophagy of adipocyte remain elusive. Here, we demonstrated endoplasmic reticulum (ER) stress and leptin were correlated with autophagy and inflammation by transcriptome sequencing of adipose tissue. Leptin-mediated inhibition of autophagy was involved in upstream reduction of ER stress proteins such as Chop, GRP78, and Atf4, since blockage of autophagy using pharmacological approach had no effect on tunicamycin-induced ER stress. Moreover, we determined KLF4, the potential transcriptional factor of Atf4, was required for the leptin-mediated autophagy in the regulation of adipocyte inflammation. Importantly, ATF4 physically interacted with ATG5 and subsequently formed a complex to promote adipocyte autophagy. Further analysis revealed that Atg5, a core component of autophagosome, was the target for leptin-mediate autophagy. In addition, leptin alleviated ER stress-induced inflammation by reducing autophagy-mediated degradation of IκB in adipocytes. Exogenous leptin treatment also ameliorated autophagy and inflammation of white adipose tissue in ob/ob mice. Taken together, our results indicated that leptin inhibited ER stress-mediated autophagy and inflammation through the negatively regulation of Atf4/Atg5 complex in adipocytes. These findings identify a new potential means for intervention of autophagy to prevent or treat obese caused metabolic syndrome of mammals.
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Affiliation(s)
- Lu Gan
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Zhenjiang Liu
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Dan Luo
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Qian Ren
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Hua Wu
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Changxing Li
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Chao Sun
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
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Goodman CA, Coenen AM, Frey JW, You JS, Barker RG, Frankish BP, Murphy RM, Hornberger TA. Insights into the role and regulation of TCTP in skeletal muscle. Oncotarget 2017; 8:18754-18772. [PMID: 27813490 PMCID: PMC5386645 DOI: 10.18632/oncotarget.13009] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 09/28/2016] [Indexed: 01/07/2023] Open
Abstract
The translationally controlled tumor protein (TCTP) is upregulated in a range of cancer cell types, in part, by the activation of the mechanistic target of rapamycin (mTOR). Recently, TCTP has also been proposed to act as an indirect activator of mTOR. While it is known that mTOR plays a major role in the regulation of skeletal muscle mass, very little is known about the role and regulation of TCTP in this post-mitotic tissue. This study shows that muscle TCTP and mTOR signaling are upregulated in a range of mouse models (mdx mouse, mechanical load-induced hypertrophy, and denervation- and immobilization-induced atrophy). Furthermore, the increase in TCTP observed in the hypertrophic and atrophic conditions occurred, in part, via a rapamycin-sensitive mTOR-dependent mechanism. However, the overexpression of TCTP was not sufficient to activate mTOR signaling (or increase protein synthesis) and is thus unlikely to take part in a recently proposed positive feedback loop with mTOR. Nonetheless, TCTP overexpression was sufficient to induce muscle fiber hypertrophy. Finally, TCTP overexpression inhibited the promoter activity of the muscle-specific ubiquitin proteasome E3-ligase, MuRF1, suggesting that TCTP may play a role in inhibiting protein degradation. These findings provide novel data on the role and regulation of TCTP in skeletal muscle in vivo.
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Affiliation(s)
- Craig A Goodman
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA.,Centre for Chronic Disease Prevention and Management, College of Health and Biomedicine, Victoria University, Melbourne, Victoria, 8001, Australia.,Institute for Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, Victoria, 8001, Australia
| | - Allison M Coenen
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA
| | - John W Frey
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA
| | - Jae-Sung You
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA
| | - Robert G Barker
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, 3086, Australia
| | - Barnaby P Frankish
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, 3086, Australia
| | - Robyn M Murphy
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, 3086, Australia
| | - Troy A Hornberger
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA
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Rodriguez J, Pierre N, Naslain D, Bontemps F, Ferreira D, Priem F, Deldicque L, Francaux M. Urolithin B, a newly identified regulator of skeletal muscle mass. J Cachexia Sarcopenia Muscle 2017; 8:583-597. [PMID: 28251839 PMCID: PMC5566634 DOI: 10.1002/jcsm.12190] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 01/01/2017] [Accepted: 01/10/2017] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND The control of muscle size is an essential feature of health. Indeed, skeletal muscle atrophy leads to reduced strength, poor quality of life, and metabolic disturbances. Consequently, strategies aiming to attenuate muscle wasting and to promote muscle growth during various (pathological) physiological states like sarcopenia, immobilization, malnutrition, or cachexia are needed to address this extensive health issue. In this study, we tested the effects of urolithin B, an ellagitannin-derived metabolite, on skeletal muscle growth. METHODS C2C12 myotubes were treated with 15 μM of urolithin B for 24 h. For in vivo experiments, mice were implanted with mini-osmotic pumps delivering continuously 10 μg/day of urolithin B during 28 days. Muscle atrophy was studied in mice with a sciatic nerve denervation receiving urolithin B by the same way. RESULTS Our experiments reveal that urolithin B enhances the growth and differentiation of C2C12 myotubes by increasing protein synthesis and repressing the ubiquitin-proteasome pathway. Genetic and pharmacological arguments support an implication of the androgen receptor. Signalling analyses suggest a crosstalk between the androgen receptor and the mTORC1 pathway, possibly via AMPK. In vivo experiments confirm that urolithin B induces muscle hypertrophy in mice and reduces muscle atrophy after the sciatic nerve section. CONCLUSIONS This study highlights the potential usefulness of urolithin B for the treatment of muscle mass loss associated with various (pathological) physiological states.
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Affiliation(s)
- Julie Rodriguez
- Institute of Neuroscience, Université catholique de Louvain, 1 place Pierre de Coubertin, 1348, Louvain-la-Neuve, Belgium.,PROCELL nutrition sprl, 2 Rue Jean Burgers, 7850, Enghien, Belgium
| | - Nicolas Pierre
- Institute of Neuroscience, Université catholique de Louvain, 1 place Pierre de Coubertin, 1348, Louvain-la-Neuve, Belgium
| | - Damien Naslain
- Institute of Neuroscience, Université catholique de Louvain, 1 place Pierre de Coubertin, 1348, Louvain-la-Neuve, Belgium
| | - Françoise Bontemps
- De Duve Institute, Université catholique de Louvain, 75 Avenue Hippocrate, 1200, Brussels, Belgium
| | - Daneel Ferreira
- Department of Biomolecular Sciences, Division of Pharmacognosy, Research Institute of Pharmaceutical Sciences, University of Mississippi, Medicinal Plant Garden, RM 104, University, MS, 38677, USA
| | - Fabian Priem
- PROCELL nutrition sprl, 2 Rue Jean Burgers, 7850, Enghien, Belgium
| | - Louise Deldicque
- Institute of Neuroscience, Université catholique de Louvain, 1 place Pierre de Coubertin, 1348, Louvain-la-Neuve, Belgium
| | - Marc Francaux
- Institute of Neuroscience, Université catholique de Louvain, 1 place Pierre de Coubertin, 1348, Louvain-la-Neuve, Belgium
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Liu HM, Ferrington DA, Baumann CW, Thompson LV. Denervation-Induced Activation of the Standard Proteasome and Immunoproteasome. PLoS One 2016; 11:e0166831. [PMID: 27875560 PMCID: PMC5119786 DOI: 10.1371/journal.pone.0166831] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 11/05/2016] [Indexed: 01/07/2023] Open
Abstract
The standard 26S proteasome is responsible for the majority of myofibrillar protein degradation leading to muscle atrophy. The immunoproteasome is an inducible form of the proteasome. While its function has been linked to conditions of atrophy, its contribution to muscle proteolysis remains unclear. Therefore, the purpose of this study was to determine if the immunoproteasome plays a role in skeletal muscle atrophy induced by denervation. Adult male C57BL/6 wild type (WT) and immunoproteasome knockout lmp7-/-/mecl-1-/- (L7M1) mice underwent tibial nerve transection on the left hindlimb for either 7 or 14 days, while control mice did not undergo surgery. Proteasome activity (caspase-, chymotrypsin-, and trypsin- like), protein content of standard proteasome (β1, β5 and β2) and immunoproteasome (LMP2, LMP7 and MECL-1) catalytic subunits were determined in the gastrocnemius muscle. Denervation induced significant atrophy and was accompanied by increased activities and protein content of the catalytic subunits in both WT and L7M1 mice. Although denervation resulted in a similar degree of muscle atrophy between strains, the mice lacking two immunoproteasome subunits showed a differential response in the extent and duration of proteasome features, including activities and content of the β1, β5 and LMP2 catalytic subunits. The results indicate that immunoproteasome deficiency alters the proteasome’s composition and activities. However, the immunoproteasome does not appear to be essential for muscle atrophy induced by denervation.
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Affiliation(s)
- Haiming M. Liu
- Department of Physical Medicine and Rehabilitation, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Deborah A. Ferrington
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Cory W. Baumann
- Department of Physical Medicine and Rehabilitation, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - LaDora V. Thompson
- Department of Physical Medicine and Rehabilitation, University of Minnesota, Minneapolis, Minnesota, United States of America
- * E-mail:
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Yoshii SR, Kuma A, Akashi T, Hara T, Yamamoto A, Kurikawa Y, Itakura E, Tsukamoto S, Shitara H, Eishi Y, Mizushima N. Systemic Analysis of Atg5-Null Mice Rescued from Neonatal Lethality by Transgenic ATG5 Expression in Neurons. Dev Cell 2016; 39:116-130. [PMID: 27693508 DOI: 10.1016/j.devcel.2016.09.001] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 06/23/2016] [Accepted: 08/31/2016] [Indexed: 12/22/2022]
Abstract
Autophagy is a cytoplasmic degradation system that is important for starvation adaptation and cellular quality control. Previously, we reported that Atg5-null mice are neonatal lethal; however, the exact cause of their death remains unknown. Here, we show that restoration of ATG5 in the brain is sufficient to rescue Atg5-null mice from neonatal lethality. This suggests that neuronal dysfunction, including suckling failure, is the primary cause of the death of Atg5-null neonates, which would further be accelerated by nutrient insufficiency due to a systemic failure in autophagy. The rescued Atg5-null mouse model, as a resource, allows us to investigate the physiological roles of autophagy in the whole body after the neonatal period. These rescued mice demonstrate previously unappreciated abnormalities such as hypogonadism and iron-deficiency anemia. These observations provide new insights into the physiological roles of the autophagy factor ATG5.
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Affiliation(s)
- Saori R Yoshii
- Department of Physiology and Cell Biology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8519, Japan; Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Akiko Kuma
- Department of Physiology and Cell Biology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8519, Japan; Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, The University of Tokyo, Tokyo 113-0033, Japan; Japan Science and Technology Agency, PRESTO, Saitama 332-0012, Japan
| | - Takumi Akashi
- Department of Human Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8519, Japan
| | - Taichi Hara
- Department of Physiology and Cell Biology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8519, Japan
| | - Atsushi Yamamoto
- Department of Physiology and Cell Biology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8519, Japan; Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, The University of Tokyo, Tokyo 113-0033, Japan; Comprehensive Reproductive Medicine, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8519, Japan
| | - Yoshitaka Kurikawa
- Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Eisuke Itakura
- Department of Physiology and Cell Biology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8519, Japan
| | - Satoshi Tsukamoto
- Laboratory Animal and Genome Sciences Section, National Institute of Radiological Sciences, Chiba 263-8555, Japan
| | - Hiroshi Shitara
- Center for Basic Technology Research, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Yoshinobu Eishi
- Department of Human Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8519, Japan
| | - Noboru Mizushima
- Department of Physiology and Cell Biology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8519, Japan; Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, The University of Tokyo, Tokyo 113-0033, Japan.
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Reilly BD, Franklin CE. Prevention of muscle wasting and osteoporosis: the value of examining novel animal models. J Exp Biol 2016; 219:2582-95. [DOI: 10.1242/jeb.128348] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
ABSTRACT
Bone mass and skeletal muscle mass are controlled by factors such as genetics, diet and nutrition, growth factors and mechanical stimuli. Whereas increased mechanical loading of the musculoskeletal system stimulates an increase in the mass and strength of skeletal muscle and bone, reduced mechanical loading and disuse rapidly promote a decrease in musculoskeletal mass, strength and ultimately performance (i.e. muscle atrophy and osteoporosis). In stark contrast to artificially immobilised laboratory mammals, animals that experience natural, prolonged bouts of disuse and reduced mechanical loading, such as hibernating mammals and aestivating frogs, consistently exhibit limited or no change in musculoskeletal performance. What factors modulate skeletal muscle and bone mass, and what physiological and molecular mechanisms protect against losses of muscle and bone during dormancy and following arousal? Understanding the events that occur in different organisms that undergo natural periods of prolonged disuse and suffer negligible musculoskeletal deterioration could not only reveal novel regulatory factors but also might lead to new therapeutic options. Here, we review recent work from a diverse array of species that has revealed novel information regarding physiological and molecular mechanisms that dormant animals may use to conserve musculoskeletal mass despite prolonged inactivity. By highlighting some of the differences and similarities in musculoskeletal biology between vertebrates that experience disparate modes of dormancy, it is hoped that this Review will stimulate new insights and ideas for future studies regarding the regulation of atrophy and osteoporosis in both natural and clinical models of muscle and bone disuse.
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Affiliation(s)
- Beau D. Reilly
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Craig E. Franklin
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
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O'Neill BT, Lee KY, Klaus K, Softic S, Krumpoch MT, Fentz J, Stanford KI, Robinson MM, Cai W, Kleinridders A, Pereira RO, Hirshman MF, Abel ED, Accili D, Goodyear LJ, Nair KS, Kahn CR. Insulin and IGF-1 receptors regulate FoxO-mediated signaling in muscle proteostasis. J Clin Invest 2016; 126:3433-46. [PMID: 27525440 DOI: 10.1172/jci86522] [Citation(s) in RCA: 111] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 06/23/2016] [Indexed: 12/20/2022] Open
Abstract
Diabetes strongly impacts protein metabolism, particularly in skeletal muscle. Insulin and IGF-1 enhance muscle protein synthesis through their receptors, but the relative roles of each in muscle proteostasis have not been fully elucidated. Using mice with muscle-specific deletion of the insulin receptor (M-IR-/- mice), the IGF-1 receptor (M-IGF1R-/- mice), or both (MIGIRKO mice), we assessed the relative contributions of IR and IGF1R signaling to muscle proteostasis. In differentiated muscle, IR expression predominated over IGF1R expression, and correspondingly, M-IR-/- mice displayed a moderate reduction in muscle mass whereas M-IGF1R-/- mice did not. However, these receptors serve complementary roles, such that double-knockout MIGIRKO mice displayed a marked reduction in muscle mass that was linked to increases in proteasomal and autophagy-lysosomal degradation, accompanied by a high-protein-turnover state. Combined muscle-specific deletion of FoxO1, FoxO3, and FoxO4 in MIGIRKO mice reversed increased autophagy and completely rescued muscle mass without changing proteasomal activity. These data indicate that signaling via IR is more important than IGF1R in controlling proteostasis in differentiated muscle. Nonetheless, the overlap of IR and IGF1R signaling is critical to the regulation of muscle protein turnover, and this regulation depends on suppression of FoxO-regulated, autophagy-mediated protein degradation.
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