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Wilhelmsen A, Stephens FB, Bennett AJ, Karagounis LG, Jones SW, Tsintzas K. Skeletal muscle myostatin mRNA expression is upregulated in aged human adults with excess adiposity but is not associated with insulin resistance and ageing. GeroScience 2024; 46:2033-2049. [PMID: 37801203 PMCID: PMC10828472 DOI: 10.1007/s11357-023-00956-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 09/20/2023] [Indexed: 10/07/2023] Open
Abstract
Myostatin negatively regulates skeletal muscle growth and appears upregulated in human obesity and associated with insulin resistance. However, observations are confounded by ageing, and the mechanisms responsible are unknown. The aim of this study was to delineate between the effects of excess adiposity, insulin resistance and ageing on myostatin mRNA expression in human skeletal muscle and to investigate causative factors using in vitro models. An in vivo cross-sectional analysis of human skeletal muscle was undertaken to isolate effects of excess adiposity and ageing per se on myostatin expression. In vitro studies employed human primary myotubes to investigate the potential involvement of cross-talk between subcutaneous adipose tissue (SAT) and skeletal muscle, and lipid-induced insulin resistance. Skeletal muscle myostatin mRNA expression was greater in aged adults with excess adiposity than age-matched adults with normal adiposity (2.0-fold higher; P < 0.05) and occurred concurrently with altered expression of genes involved in the maintenance of muscle mass but did not differ between younger and aged adults with normal adiposity. Neither chronic exposure to obese SAT secretome nor acute elevation of fatty acid availability (which induced insulin resistance) replicated the obesity-mediated upregulation of myostatin mRNA expression in vitro. In conclusion, skeletal muscle myostatin mRNA expression is uniquely upregulated in aged adults with excess adiposity and insulin resistance but not by ageing alone. This does not appear to be mediated by the SAT secretome or by lipid-induced insulin resistance. Thus, factors intrinsic to skeletal muscle may be responsible for the obesity-mediated upregulation of myostatin, and future work to establish causality is required.
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Affiliation(s)
- Andrew Wilhelmsen
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, UK
| | | | - Andrew J Bennett
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, UK
| | - Leonidas G Karagounis
- Mary MacKillop Institute for Health Research (MMIHR), Melbourne, Australian Catholic University, Melbourne, Australia
- Institute of Social and Preventive Medicine (ISPM), University of Bern, Bern, Switzerland
| | - Simon W Jones
- Institute of Inflammation and Ageing, MRC Versus Arthritis Centre for Musculoskeletal Ageing Research, Queen Elizabeth Hospital, The University of Birmingham, Birmingham, UK
| | - Kostas Tsintzas
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, UK.
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Bahat G, Ozkok S. The Current Landscape of Pharmacotherapies for Sarcopenia. Drugs Aging 2024; 41:83-112. [PMID: 38315328 DOI: 10.1007/s40266-023-01093-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/28/2023] [Indexed: 02/07/2024]
Abstract
Sarcopenia is a skeletal muscle disorder characterized by progressive and generalized decline in muscle mass and function. Although it is mostly known as an age-related disorder, it can also occur secondary to systemic diseases such as malignancy or organ failure. It has demonstrated a significant relationship with adverse outcomes, e.g., falls, disabilities, and even mortality. Several breakthroughs have been made to find a pharmaceutical therapy for sarcopenia over the years, and some have come up with promising findings. Yet still no drug has been approved for its treatment. The key factor that makes finding an effective pharmacotherapy so challenging is the general paradigm of standalone/single diseases, traditionally adopted in medicine. Today, it is well known that sarcopenia is a complex disorder caused by multiple factors, e.g., imbalance in protein turnover, satellite cell and mitochondrial dysfunction, hormonal changes, low-grade inflammation, senescence, anorexia of aging, and behavioral factors such as low physical activity. Therefore, pharmaceuticals, either alone or combined, that exhibit multiple actions on these factors simultaneously will likely be the drug of choice to manage sarcopenia. Among various drug options explored throughout the years, testosterone still has the most cumulated evidence regarding its effects on muscle health and its safety. A mas receptor agonist, BIO101, stands out as a recent promising pharmaceutical. In addition to the conventional strategies (i.e., nutritional support and physical exercise), therapeutics with multiple targets of action or combination of multiple therapeutics with different targets/modes of action appear to promise greater benefit for the prevention and treatment of sarcopenia.
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Affiliation(s)
- Gulistan Bahat
- Division of Geriatrics, Department of Internal Medicine, Istanbul Medical School, Istanbul University, Capa, 34390, Istanbul, Turkey.
| | - Serdar Ozkok
- Division of Geriatrics, Department of Internal Medicine, Hatay Training and Research Hospital, Hatay, 31040, Turkey
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Gellhaus B, Böker KO, Schilling AF, Saul D. Therapeutic Consequences of Targeting the IGF-1/PI3K/AKT/FOXO3 Axis in Sarcopenia: A Narrative Review. Cells 2023; 12:2787. [PMID: 38132107 PMCID: PMC10741475 DOI: 10.3390/cells12242787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 12/05/2023] [Accepted: 12/06/2023] [Indexed: 12/23/2023] Open
Abstract
The high prevalence of sarcopenia in an aging population has an underestimated impact on quality of life by increasing the risk of falls and subsequent hospitalization. Unfortunately, the application of the major established key therapeutic-physical activity-is challenging in the immobile and injured sarcopenic patient. Consequently, novel therapeutic directions are needed. The transcription factor Forkhead-Box-Protein O3 (FOXO3) may be an option, as it and its targets have been observed to be more highly expressed in sarcopenic muscle. In such catabolic situations, Foxo3 induces the expression of two muscle specific ubiquitin ligases (Atrogin-1 and Murf-1) via the PI3K/AKT pathway. In this review, we particularly evaluate the potential of Foxo3-targeted gene therapy. Foxo3 knockdown has been shown to lead to increased muscle cross sectional area, through both the AKT-dependent and -independent pathways and the reduced impact on the two major downstream targets Atrogin-1 and Murf-1. Moreover, a Foxo3 reduction suppresses apoptosis, activates satellite cells, and initiates their differentiation into muscle cells. While this indicates a critical role in muscle regeneration, this mechanism might exhaust the stem cell pool, limiting its clinical applicability. As systemic Foxo3 knockdown has also been associated with risks of inflammation and cancer progression, a muscle-specific approach would be necessary. In this review, we summarize the current knowledge on Foxo3 and conceptualize a specific and targeted therapy that may circumvent the drawbacks of systemic Foxo3 knockdown. This approach presumably would limit the side effects and enable an activity-independent positive impact on skeletal muscle.
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Affiliation(s)
- Benjamin Gellhaus
- Department of Trauma, Orthopedics and Reconstructive Surgery, Georg-August University of Goettingen, 37075 Goettingen, Germany; (B.G.); (K.O.B.); (A.F.S.)
| | - Kai O. Böker
- Department of Trauma, Orthopedics and Reconstructive Surgery, Georg-August University of Goettingen, 37075 Goettingen, Germany; (B.G.); (K.O.B.); (A.F.S.)
| | - Arndt F. Schilling
- Department of Trauma, Orthopedics and Reconstructive Surgery, Georg-August University of Goettingen, 37075 Goettingen, Germany; (B.G.); (K.O.B.); (A.F.S.)
| | - Dominik Saul
- Department of Trauma, Orthopedics and Reconstructive Surgery, Georg-August University of Goettingen, 37075 Goettingen, Germany; (B.G.); (K.O.B.); (A.F.S.)
- Department of Trauma and Reconstructive Surgery, Eberhard Karls University Tuebingen, BG Trauma Center Tuebingen, 72072 Tuebingen, Germany
- Division of Endocrinology, Mayo Clinic, Rochester, MN 55905, USA
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN 55905, USA
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Pang X, Zhang P, Chen X, Liu W. Ubiquitin-proteasome pathway in skeletal muscle atrophy. Front Physiol 2023; 14:1289537. [PMID: 38046952 PMCID: PMC10690626 DOI: 10.3389/fphys.2023.1289537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 11/06/2023] [Indexed: 12/05/2023] Open
Abstract
Skeletal muscles underpin myriad human activities, maintaining an intricate balance between protein synthesis and degradation crucial to muscle mass preservation. Historically, disruptions in this balance-where degradation overshadows synthesis-have marked the onset of muscle atrophy, a condition diminishing life quality and, in grave instances, imperiling life itself. While multiple protein degradation pathways exist-including the autophagy-lysosome, calcium-dependent calpain, and cysteine aspartate protease systems-the ubiquitin-proteasome pathway emerges as an especially cardinal avenue for intracellular protein degradation, wielding pronounced influence over the muscle atrophy trajectory. This paper ventures a panoramic view of predominant muscle atrophy types, accentuating the ubiquitin-proteasome pathway's role therein. Furthermore, by drawing from recent scholarly advancements, we draw associations between the ubiquitin-proteasome pathway and specific pathological conditions linked to muscle atrophy. Our exploration seeks to shed light on the ubiquitin-proteasome pathway's significance in skeletal muscle dynamics, aiming to pave the way for innovative therapeutic strategies against muscle atrophy and affiliated muscle disorders.
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Affiliation(s)
- XiangSheng Pang
- Department of Physical Education, College of Education, Zhejiang University, Hangzhou, Zhejiang, China
- National Key Laboratory of Human Factors Engineering, China Astronaut Research and Training Center, Beijing, China
| | - Peng Zhang
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - XiaoPing Chen
- National Key Laboratory of Human Factors Engineering, China Astronaut Research and Training Center, Beijing, China
| | - WenMing Liu
- Department of Physical Education, College of Education, Zhejiang University, Hangzhou, Zhejiang, China
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Song J, Widen SG, Wolf SE, EI Ayadi A. Skeletal muscle transcriptome is affected by age in severely burned mice. Sci Rep 2022; 12:21584. [PMID: 36517580 PMCID: PMC9748408 DOI: 10.1038/s41598-022-26040-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 12/08/2022] [Indexed: 12/23/2022] Open
Abstract
Severe burn results in muscle wasting affecting quality of life in both children and adults. Biologic metabolic profiles are noticeably distinctive in childhood. We posit that muscle gene expression profiles are differentially regulated in response to severe burns in young animals. Twelve C57BL6 male mice, including young (5 weeks-old) and adults (11 weeks-old), received either scald burn, or sham procedure. Mouse muscle tissue was harvested 24 h later for Next Generation Sequence analysis. Our results showed 662 downregulated and 450 upregulated genes in gastrocnemius of young mice compared to adults without injury. After injury, we found 74/75 downregulated genes and 107/128 upregulated genes in both burned groups compared to respective uninjured age groups. VEGFA-VEGFR2, focal adhesion, and nuclear receptor meta-pathways were the top 3 gene pathways undergoing a differential change in response to age. Of note, the proteasome degradation pathway showed the most similar changes in both adult and young burned animals. This study demonstrates the characteristic profile of gene expression in skeletal muscle in young and adult burned mice. Prominent age effects were revealed in transcriptional levels with increased alterations of genes, miRNAs, pathways, and interactions.
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Affiliation(s)
- Juquan Song
- grid.176731.50000 0001 1547 9964Department of Surgery, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555-0644 USA
| | - Steven G. Widen
- grid.176731.50000 0001 1547 9964Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX USA
| | - Steven E. Wolf
- grid.176731.50000 0001 1547 9964Department of Surgery, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555-0644 USA
| | - Amina EI Ayadi
- grid.176731.50000 0001 1547 9964Department of Surgery, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555-0644 USA
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Panteli N, Demertzioglou M, Feidantsis K, Karapanagiotis S, Tsele N, Tsakoniti K, Gkagkavouzis K, Mylonas CC, Kormas KA, Mente E, Antonopoulou E. Advances in understanding the mitogenic, metabolic, and cell death signaling in teleost development: the case of greater amberjack (Seriola dumerili, Risso 1810). Fish Physiol Biochem 2022; 48:1665-1684. [PMID: 36459361 DOI: 10.1007/s10695-022-01146-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 11/16/2022] [Indexed: 06/17/2023]
Abstract
Cell growth and differentiation signals of insulin-like growth factor-1 (IGF-1), a key regulator in embryonic and postnatal development, are mediated through the IGF-1 receptor (IGF-1R), which activates several downstream pathways. The present study aims to address crucial organogenesis and development pathways including Akt, MAPKs, heat shock response, apoptotic and autophagic machinery, and energy metabolism in relation to IGF-1R activation during five developmental stages of reared Seriola dumerili: 1 day prior to hatching fertilized eggs (D-1), hatching day (D0), 3 days post-hatching larvae (D3), 33 (D33) and 46 (D46) days post-hatching juveniles. During both the fertilized eggs stage and larval-to-juvenile transition, IGF-1R/Akt pathway activation may mediate the hypertrophic signaling, while p44/42 MAPK phosphorylation was apparent at S. dumerili post-hatching processes and juvenile organs completion. On the contrary, apoptosis was induced during embryogenesis and autophagy at hatching day indicating a potential involvement in morphogenetic rearrangements and yolk-sac reserves depletion. Larvae morphogenesis was accompanied by a metabolic turnover with increased substantial energy consumption. The findings of the present study demonstrate the developmental stages-specific shift in critical signaling pathways during the ontogeny of reared S. dumerili.
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Affiliation(s)
- Nikolas Panteli
- Laboratory of Animal Physiology, Department of Zoology, School of Biology, Faculty of Sciences, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece
| | - Maria Demertzioglou
- Laboratory of Animal Physiology, Department of Zoology, School of Biology, Faculty of Sciences, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece
| | - Konstantinos Feidantsis
- Laboratory of Animal Physiology, Department of Zoology, School of Biology, Faculty of Sciences, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece
| | | | | | | | - Konstantinos Gkagkavouzis
- Department of Genetics, Development and Molecular Biology, School of Biology, Faculty of Sciences, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece
- Genomics and Epigenomics Translational Research (GENeTres), Center for Interdisciplinary Research and Innovation (CIRI-AUTH), Balkan Center, Buildings A & B 10th km Thessaloniki-Thermi Rd, P.O. Box 8318, 57001, Thessaloniki, Greece
| | - Constantinos C Mylonas
- Institute of Marine Biology, Biotechnology and Aquaculture, Hellenic Center for Marine Research, P.O. Box 2214, 71003, Heraklion, Crete, Greece
| | - Konstantinos Ar Kormas
- Department of Ichthyology and Aquatic Environment, School of Agricultural Sciences, University of Thessaly, 38446, Volos, Greece
| | - Eleni Mente
- School of Veterinary Medicine, Laboratory of Ichthyology-Culture and Pathology of Aquatic Animals, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece
| | - Efthimia Antonopoulou
- Laboratory of Animal Physiology, Department of Zoology, School of Biology, Faculty of Sciences, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece.
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El Assar M, Álvarez-Bustos A, Sosa P, Angulo J, Rodríguez-Mañas L. Effect of Physical Activity/Exercise on Oxidative Stress and Inflammation in Muscle and Vascular Aging. Int J Mol Sci 2022; 23:ijms23158713. [PMID: 35955849 PMCID: PMC9369066 DOI: 10.3390/ijms23158713] [Citation(s) in RCA: 50] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 07/28/2022] [Accepted: 08/03/2022] [Indexed: 11/20/2022] Open
Abstract
Functional status is considered the main determinant of healthy aging. Impairment in skeletal muscle and the cardiovascular system, two interrelated systems, results in compromised functional status in aging. Increased oxidative stress and inflammation in older subjects constitute the background for skeletal muscle and cardiovascular system alterations. Aged skeletal muscle mass and strength impairment is related to anabolic resistance, mitochondrial dysfunction, increased oxidative stress and inflammation as well as a reduced antioxidant response and myokine profile. Arterial stiffness and endothelial function stand out as the main cardiovascular alterations related to aging, where increased systemic and vascular oxidative stress and inflammation play a key role. Physical activity and exercise training arise as modifiable determinants of functional outcomes in older persons. Exercise enhances antioxidant response, decreases age-related oxidative stress and pro-inflammatory signals, and promotes the activation of anabolic and mitochondrial biogenesis pathways in skeletal muscle. Additionally, exercise improves endothelial function and arterial stiffness by reducing inflammatory and oxidative damage signaling in vascular tissue together with an increase in antioxidant enzymes and nitric oxide availability, globally promoting functional performance and healthy aging. This review focuses on the role of oxidative stress and inflammation in aged musculoskeletal and vascular systems and how physical activity/exercise influences functional status in the elderly.
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Affiliation(s)
- Mariam El Assar
- Fundación para la Investigación Biomédica del Hospital Universitario de Getafe, 28905 Getafe, Spain
- Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Alejandro Álvarez-Bustos
- Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Patricia Sosa
- Fundación para la Investigación Biomédica del Hospital Universitario de Getafe, 28905 Getafe, Spain
| | - Javier Angulo
- Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Servicio de Histología-Investigación, Unidad de Investigación Traslacional en Cardiología (IRYCIS-UFV), Hospital Universitario Ramón y Cajal, 28034 Madrid, Spain
| | - Leocadio Rodríguez-Mañas
- Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Servicio de Geriatría, Hospital Universitario de Getafe, 28905 Getafe, Spain
- Correspondence: ; Tel.: +34-91-683-93-60 (ext. 6411)
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Hughes DC, Baehr LM, Waddell DS, Sharples AP, Bodine SC. Ubiquitin Ligases in Longevity and Aging Skeletal Muscle. Int J Mol Sci 2022; 23:7602. [PMID: 35886949 DOI: 10.3390/ijms23147602] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 07/07/2022] [Accepted: 07/08/2022] [Indexed: 12/07/2022] Open
Abstract
The development and prevalence of diseases associated with aging presents a global health burden on society. One hallmark of aging is the loss of proteostasis which is caused in part by alterations to the ubiquitin-proteasome system (UPS) and lysosome-autophagy system leading to impaired function and maintenance of mass in tissues such as skeletal muscle. In the instance of skeletal muscle, the impairment of function occurs early in the aging process and is dependent on proteostatic mechanisms. The UPS plays a pivotal role in degradation of misfolded and aggregated proteins. For the purpose of this review, we will discuss the role of the UPS system in the context of age-related loss of muscle mass and function. We highlight the significant role that E3 ubiquitin ligases play in the turnover of key components (e.g., mitochondria and neuromuscular junction) essential to skeletal muscle function and the influence of aging. In addition, we will briefly discuss the contribution of the UPS system to lifespan. By understanding the UPS system as part of the proteostasis network in age-related diseases and disorders such as sarcopenia, new discoveries can be made and new interventions can be developed which will preserve muscle function and maintain quality of life with advancing age.
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Opazo R, Angel B, Márquez C, Lera L, Cardoso Dos Santos GR, Monnerat G, Albala C. Sarcopenic metabolomic profile reflected a sarcopenic phenotype associated with amino acid and essential fatty acid changes. Metabolomics 2021; 17:83. [PMID: 34498155 DOI: 10.1007/s11306-021-01832-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 08/25/2021] [Indexed: 01/08/2023]
Abstract
INTRODUCTION Although sarcopenia greatly affects health and quality of life in older people, its pathophysiological causes are not fully elucidated. To face this challenge, omics technologies can be used. The metabolome gives a vision of the interaction between the genome and the environment through metabolic networks, thus contributing in clarifying the pathophysiology of the sarcopenic phenotype. OBJECTIVES The main goal of this study was to compare the plasma metabolome of sarcopenic and non-sarcopenic older people. METHODS Cross-sectional study of 20 sarcopenic and 21 non-sarcopenic older subjects with available frozen plasma samples. Non-targeted metabolomic study by ultra-high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS) analysis with later bioinformatics data analysis. Once the significantly different metabolites were identified, the KEGG database was used on them to establish which were the metabolic pathways mainly involved. RESULTS From 657 features identified, 210 showed significant differences between the study groups, and 30 had a FoldChangeLog2 > 2. The most interesting metabolic pathways found with the KEGG database were the biosynthesis of amino acids, arginine and proline metabolism, the biosynthesis of alkaloids derived from ornithine, linoleic acid metabolism, and the biosynthesis of unsaturated fatty acids. CONCLUSIONS The study results allowed us to confirm that the concept of "sarcopenic phenotype" is also witnessed at the plasma metabolite levels. The non-targeted metabolomics study can open a wide view of the sarcopenic features changes at the plasma level, which would be linked to the sarcopenic physiopathological alterations.
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Affiliation(s)
- Rafael Opazo
- Laboratorio de Biotecnología INTA, Universidad de Chile, Santiago, Chile
- Laboratório de Genômica Funcional e Bioinformática, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Bárbara Angel
- Unidad de Nutrición Pública INTA, Universidad de Chile, Santiago, Chile
| | - Carlos Márquez
- Unidad de Nutrición Pública INTA, Universidad de Chile, Santiago, Chile
| | - Lydia Lera
- Unidad de Nutrición Pública INTA, Universidad de Chile, Santiago, Chile
- Latin Division, Keiser University, Fort Lauderdale, USA
| | - Gustavo R Cardoso Dos Santos
- Laboratório de Pesquisa, Desenvolvimento e Inovação (LPDI-LADETEC), Instituto de Química Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - Gustavo Monnerat
- Laboratório de Pesquisa, Desenvolvimento e Inovação (LPDI-LADETEC), Instituto de Química Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
- Instituto Nacional de Cardiologia, Rio de Janeiro, Brazil
| | - Cecilia Albala
- Unidad de Nutrición Pública INTA, Universidad de Chile, Santiago, Chile.
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Jayawardena TU, Kim SY, Jeon YJ. Sarcopenia; functional concerns, molecular mechanisms involved, and seafood as a nutritional intervention - review article. Crit Rev Food Sci Nutr 2021; 63:1983-2003. [PMID: 34459311 DOI: 10.1080/10408398.2021.1969889] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The fundamental basis for the human function is provided by skeletal muscle. Advancing age causes selective fiber atrophy, motor unit loss, and hybrid fiber formation resulting in hampered mass and strength, thus referred to as sarcopenia. Influence on the loss of independence of aged adults, contribute toward inclined healthcare costs conveys the injurious impact. The current understating of age-related skeletal muscle changes are addressed in this review, and further discusses mechanisms regulating protein turnover, although they do not completely define the process yet. Moreover, the reduced capacity of muscle regeneration due to impairment of satellite cell activation and proliferation with neuronal, immunological, hormonal factors were brought into the light of attention. Nevertheless, complete understating of sarcopenia requires disentangling it from disuse and disease. Nutritional intervention is considered a potentially preventable factor contributing to sarcopenia. Seafood is a crucial player in the fight against hunger and malnutrition, where it consists of macro and micronutrients. Hence, the review shed light on seafood as a nutritional intrusion in the treatment and prevention of sarcopenia. Understanding multiple factors will provide therapeutic targets in the prevention, treatment, and overcoming adverse effects of sarcopenia.
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Affiliation(s)
- Thilina U Jayawardena
- Department of Marine Life Sciences, Jeju National University, Jeju, Republic of Korea
| | - Seo-Young Kim
- Division of Practical Application, Honam National Institute of Biological Resources, Mokpo-si, Korea
| | - You-Jin Jeon
- Department of Marine Life Sciences, Jeju National University, Jeju, Republic of Korea.,Marine Science Institute, Jeju National University, Jeju, Jeju Self-Governing Province, Republic of Korea
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11
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Latham CM, Brightwell CR, Keeble AR, Munson BD, Thomas NT, Zagzoog AM, Fry CS, Fry JL. Vitamin D Promotes Skeletal Muscle Regeneration and Mitochondrial Health. Front Physiol 2021; 12:660498. [PMID: 33935807 PMCID: PMC8079814 DOI: 10.3389/fphys.2021.660498] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 03/17/2021] [Indexed: 12/13/2022] Open
Abstract
Vitamin D is an essential nutrient for the maintenance of skeletal muscle and bone health. The vitamin D receptor (VDR) is present in muscle, as is CYP27B1, the enzyme that hydroxylates 25(OH)D to its active form, 1,25(OH)D. Furthermore, mounting evidence suggests that vitamin D may play an important role during muscle damage and regeneration. Muscle damage is characterized by compromised muscle fiber architecture, disruption of contractile protein integrity, and mitochondrial dysfunction. Muscle regeneration is a complex process that involves restoration of mitochondrial function and activation of satellite cells (SC), the resident skeletal muscle stem cells. VDR expression is strongly upregulated following injury, particularly in central nuclei and SCs in animal models of muscle injury. Mechanistic studies provide some insight into the possible role of vitamin D activity in injured muscle. In vitro and in vivo rodent studies show that vitamin D mitigates reactive oxygen species (ROS) production, augments antioxidant capacity, and prevents oxidative stress, a common antagonist in muscle damage. Additionally, VDR knockdown results in decreased mitochondrial oxidative capacity and ATP production, suggesting that vitamin D is crucial for mitochondrial oxidative phosphorylation capacity; an important driver of muscle regeneration. Vitamin D regulation of mitochondrial health may also have implications for SC activity and self-renewal capacity, which could further affect muscle regeneration. However, the optimal timing, form and dose of vitamin D, as well as the mechanism by which vitamin D contributes to maintenance and restoration of muscle strength following injury, have not been determined. More research is needed to determine mechanistic action of 1,25(OH)D on mitochondria and SCs, as well as how this action manifests following muscle injury in vivo. Moreover, standardization in vitamin D sufficiency cut-points, time-course study of the efficacy of vitamin D administration, and comparison of multiple analogs of vitamin D are necessary to elucidate the potential of vitamin D as a significant contributor to muscle regeneration following injury. Here we will review the contribution of vitamin D to skeletal muscle regeneration following injury.
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Affiliation(s)
- Christine M Latham
- Department of Athletic Training and Clinical Nutrition, University of Kentucky, Lexington, KY, United States
| | - Camille R Brightwell
- Department of Athletic Training and Clinical Nutrition, University of Kentucky, Lexington, KY, United States
| | - Alexander R Keeble
- Department of Athletic Training and Clinical Nutrition, University of Kentucky, Lexington, KY, United States
| | - Brooke D Munson
- Department of Athletic Training and Clinical Nutrition, University of Kentucky, Lexington, KY, United States
| | - Nicholas T Thomas
- Department of Athletic Training and Clinical Nutrition, University of Kentucky, Lexington, KY, United States
| | - Alyaa M Zagzoog
- Department of Athletic Training and Clinical Nutrition, University of Kentucky, Lexington, KY, United States
| | - Christopher S Fry
- Department of Athletic Training and Clinical Nutrition, University of Kentucky, Lexington, KY, United States.,Center for Muscle Biology, College of Health Sciences, University of Kentucky, Lexington, KY, United States
| | - Jean L Fry
- Department of Athletic Training and Clinical Nutrition, University of Kentucky, Lexington, KY, United States.,Center for Muscle Biology, College of Health Sciences, University of Kentucky, Lexington, KY, United States
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12
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Abstract
Skeletal muscle atrophy is a common side effect of most human diseases. Muscle loss is not only detrimental for the quality of life but it also dramatically impairs physiological processes of the organism and decreases the efficiency of medical treatments. While hypothesized for years, the existence of an atrophying programme common to all pathologies is still incompletely solved despite the discovery of several actors and key regulators of muscle atrophy. More than a decade ago, the discovery of a set of genes, whose expression at the mRNA levels were similarly altered in different catabolic situations, opened the way of a new concept: the presence of atrogenes, i.e. atrophy-related genes. Importantly, the atrogenes are referred as such on the basis of their mRNA content in atrophying muscles, the regulation at the protein level being sometimes more complicate to elucidate. It should be noticed that the atrogenes are markers of atrophy and that their implication as active inducers of atrophy is still an open question for most of them. While the atrogene family has grown over the years, it has mostly been incremented based on data coming from rodent models. Whether the rodent atrogenes are valid for humans still remain to be established. An "atrogene" was originally defined as a gene systematically up- or down-regulated in several catabolic situations. Even if recent works often restrict this notion to the up-regulation of a limited number of proteolytic enzymes, it is important to keep in mind the big picture view. In this review, we provide an update of the validated and potential rodent atrogenes and the metabolic pathways they belong, and based on recent work, their relevance in human physio-pathological situations. We also propose a more precise definition of the atrogenes that integrates rapid recovery when catabolic stimuli are stopped or replaced by anabolic ones.
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Affiliation(s)
- Daniel Taillandier
- Université Clermont Auvergne, INRA, UNH, Unité de Nutrition Humaine, CRNH Auvergne, F-63000, Clermont-Ferrand, France.
| | - Cécile Polge
- Université Clermont Auvergne, INRA, UNH, Unité de Nutrition Humaine, CRNH Auvergne, F-63000, Clermont-Ferrand, France
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13
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Picca A, Calvani R, Leeuwenburgh C, Coelho-Junior HJ, Bernabei R, Landi F, Marzetti E. Targeting mitochondrial quality control for treating sarcopenia: lessons from physical exercise. Expert Opin Ther Targets 2018; 23:153-160. [PMID: 30580640 DOI: 10.1080/14728222.2019.1559827] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
INTRODUCTION Mitochondrial dysfunction is a hallmark of aging and hence is a candidate target for intervention. Sarcopenia of aging is a prevalent condition and is associated with numerous negative health outcomes. Alterations in mitochondrial homeostasis have been reported in sarcopenic muscle. Area covered: We discuss the evidence that points to mitochondrial dysfunction having a causative role in sarcopenia and the mechanisms involved in the accumulation of damaged mitochondria in the aged muscle. We also discuss the effects of physical exercise on mitochondrial quality control and muscle health in advanced age. Expert opinion: In the aged muscle, the mitochondrial quality control axis is altered at several levels, including proteostasis, biogenesis, dynamics, and autophagy. Mitochondrial dysfunction arising from impaired quality control is thought to play a major role in the pathogenesis of sarcopenia. Physical exercise is the most effective strategy for the management of sarcopenia. Improvements in mitochondrial health and plasticity may mediate several beneficial effects of exercise in muscle. A greater understanding of the molecular changes that occur in the aged muscle following exercise and how they impact mitochondrial homeostasis is necessary for the exploration of potential targets that are amenable for interventions.
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Affiliation(s)
- Anna Picca
- a Università Cattolica del Sacro Cuore, Institute of Internal Medicine and Geriatrics , Rome , Italy.,b Fondazione Policlinico Universitario "Agostino Gemelli" IRCCS , Rome , Italy
| | - Riccardo Calvani
- a Università Cattolica del Sacro Cuore, Institute of Internal Medicine and Geriatrics , Rome , Italy.,b Fondazione Policlinico Universitario "Agostino Gemelli" IRCCS , Rome , Italy
| | - Christiaan Leeuwenburgh
- c Department of Aging and Geriatric Research , Institute on Aging, University of Florida , Gainesville , FL , USA
| | - Hélio José Coelho-Junior
- a Università Cattolica del Sacro Cuore, Institute of Internal Medicine and Geriatrics , Rome , Italy.,d Applied Kinesiology Laboratory-LCA , School of Physical Education, University of Campinas , Campinas , Brazil
| | - Roberto Bernabei
- a Università Cattolica del Sacro Cuore, Institute of Internal Medicine and Geriatrics , Rome , Italy.,b Fondazione Policlinico Universitario "Agostino Gemelli" IRCCS , Rome , Italy
| | - Francesco Landi
- a Università Cattolica del Sacro Cuore, Institute of Internal Medicine and Geriatrics , Rome , Italy.,b Fondazione Policlinico Universitario "Agostino Gemelli" IRCCS , Rome , Italy
| | - Emanuele Marzetti
- b Fondazione Policlinico Universitario "Agostino Gemelli" IRCCS , Rome , Italy
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14
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Vélez EJ, Azizi S, Verheyden D, Salmerón C, Lutfi E, Sánchez-Moya A, Navarro I, Gutiérrez J, Capilla E. Proteolytic systems' expression during myogenesis and transcriptional regulation by amino acids in gilthead sea bream cultured muscle cells. PLoS One 2017; 12:e0187339. [PMID: 29261652 DOI: 10.1371/journal.pone.0187339] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 10/18/2017] [Indexed: 12/30/2022] Open
Abstract
Proteolytic systems exert an important role in vertebrate muscle controlling protein turnover, recycling of amino acids (AA) or its use for energy production, as well as other functions like myogenesis. In fish, proteolytic systems are crucial for the relatively high muscle somatic index they possess, and because protein is the most important dietary component. Thus in this study, the molecular profile of proteolytic markers (calpains, cathepsins and ubiquitin-proteasome system (UbP) members) were analyzed during gilthead sea bream (Sparus aurata) myogenesis in vitro and under different AA treatments. The gene expression of calpains (capn1, capn3 and capns1b) decreased progressively during myogenesis together with the proteasome member n3; whereas capn2, capns1a, capns1b and ubiquitin (ub) remained stable. Contrarily, the cathepsin D (ctsd) paralogs and E3 ubiquitin ligases mafbx and murf1, showed a significant peak in gene expression at day 8 of culture that slightly decreased afterwards. Moreover, the protein expression analyzed for selected molecules presented in general the same profile of the mRNA levels, which was confirmed by correlation analysis. These data suggest that calpains seem to be more important during proliferation, while cathepsins and the UbP system appear to be required for myogenic differentiation. Concerning the transcriptional regulation by AA, the recovery of their levels after a short starvation period did not show effects on cathepsins expression, whereas it down-regulated the expression of capn3, capns1b, mafbx, murf1 and up-regulated n3. With regards to AA deficiencies, the major changes occurred at day 2, when leucine limitation suppressed ctsb and ctsl expression. Besides at the same time, both leucine and lysine deficiencies increased the expression of mafbx and murf1 and decreased that of n3. Overall, the opposite nutritional regulation observed, especially for the UbP members, points out an efficient and complementary role of these factors that could be useful in gilthead sea bream diets optimization.
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15
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Abstract
Many physiological changes occur with aging. These changes often, directly or indirectly, result in a deterioration of the quality of life and even in a shortening of life expectancy. Besides increased levels of reactive oxygen species, DNA damage and cell apoptosis, another important factor affecting the aging process involves a systemic chronic low-grade inflammation. This condition has already been shown to be interrelated with several (sub)clinical conditions, such as insulin resistance, atherosclerosis and Alzheimer's disease. Recent evidence, however, shows that chronic low-grade inflammation also contributes to the loss of muscle mass, strength and functionality, referred to as sarcopenia, as it affects both muscle protein breakdown and synthesis through several signaling pathways. Classic interventions to counteract age-related muscle wasting mainly focus on resistance training and/or protein supplementation to overcome the anabolic inflexibility from which elderly suffer. Although the elderly benefit from these classic interventions, the therapeutic potential of anti-inflammatory strategies is of great interest, as these might add up to/support the anabolic effect of resistance exercise and/or protein supplementation. In this review, the molecular interaction between inflammation, anabolic sensitivity and muscle protein metabolism in sarcopenic elderly will be addressed.
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Affiliation(s)
- Sebastiaan Dalle
- Exercise Physiology Research Group, Department of Kinesiology, KU Leuven, Leuven, Belgium
| | - Lenka Rossmeislova
- Department for the Study of Obesity and Diabetes, Third Faculty of Medicine, Charles University, Prague, Czechia
| | - Katrien Koppo
- Exercise Physiology Research Group, Department of Kinesiology, KU Leuven, Leuven, Belgium
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16
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Abstract
We present the hypothesis that an accumulation of dysfunctional mitochondria initiates a signaling cascade leading to motor neuron and muscle fiber death and culminating in sarcopenia. Interactions between neural and muscle cells that contain dysfunctional mitochondria exacerbate sarcopenia. Preventing sarcopenia will require identifying mitochondrial sources of dysfunction that are reversible.
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Affiliation(s)
- Stephen E Alway
- 1Division of Exercise Physiology; 2Center for Cardiovascular and Respiratory Sciences, and Mitochondria, Metabolism, and Bioenergetics; and 3Centers for Neuroscience, West Virginia University School of Medicine, Morgantown, WV
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17
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Eby JM, Abdelkarim H, Albee LJ, Tripathi A, Gao X, Volkman BF, Gaponenko V, Majetschak M. Functional and structural consequences of chemokine (C-X-C motif) receptor 4 activation with cognate and non-cognate agonists. Mol Cell Biochem 2017; 434:143-51. [PMID: 28455789 DOI: 10.1007/s11010-017-3044-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 04/22/2017] [Indexed: 01/27/2023]
Abstract
Chemokine (C-X-C motif) receptor 4 (CXCR4) regulates cell trafficking and plays important roles in the immune system. Ubiquitin has recently been identified as an endogenous non-cognate agonist of CXCR4, which activates CXCR4 via interaction sites that are distinct from those of the cognate agonist C-X-C motif chemokine ligand 12 (CXCL12). As compared with CXCL12, chemotactic activities of ubiquitin in primary human cells are poorly characterized. Furthermore, evidence for functional selectivity of CXCR4 agonists is lacking, and structural consequences of ubiquitin binding to CXCR4 are unknown. Here, we show that ubiquitin and CXCL12 have comparable chemotactic activities in normal human peripheral blood mononuclear cells, monocytes, vascular smooth muscle, and endothelial cells. Chemotactic activities of the CXCR4 ligands could be inhibited with the selective CXCR4 antagonist AMD3100 and with a peptide analogue of the second transmembrane domain of CXCR4. In human monocytes, ubiquitin- and CXCL12-induced chemotaxis could be inhibited with pertussis toxin and with inhibitors of phospholipase C, phosphatidylinositol 3 kinase, and extracellular signal-regulated kinase 1/2. Both agonists induced inositol trisphosphate production in vascular smooth muscle cells, which could be inhibited with AMD3100. In β-arrestin recruitment assays, ubiquitin did not sufficiently recruit β-arrestin2 to CXCR4 (EC50 > 10 μM), whereas the EC50 for CXCL12 was 4.6 nM (95% confidence interval 3.1-6.1 nM). Both agonists induced similar chemical shift changes in the 13C-1H-heteronuclear single quantum correlation (HSQC) spectrum of CXCR4 in membranes, whereas CXCL11 did not significantly alter the 13C-1H-HSQC spectrum of CXCR4. Our findings point towards ubiquitin as a biased agonist of CXCR4.
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18
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Abstract
The ubiquitin-proteasome system (UPS) is the main regulatory mechanism of protein degradation in skeletal muscle. The ubiquitin-ligase enzymes (E3s) have a central role in determining the selectivity and specificity of the UPS. Since their identification in 2001, the muscle specific E3s, muscle RING finger-1 (MuRF-1) and muscle atrophy F-box (MAFbx), have been shown to be implicated in the regulation of skeletal muscle atrophy in various pathological and physiological conditions. This review aims to explore the involvement of MuRF-1 and MAFbx in catabolism of skeletal muscle during various pathologies, such as cancer cachexia, sarcopenia of aging, chronic kidney disease (CKD), diabetes, and chronic obstructive pulmonary disease (COPD). In addition, the effects of various lifestyle and modifiable factors (e.g. nutrition, exercise, cigarette smoking, and alcohol) on MuRF-1 and MAFbx regulation will be discussed. Finally, evidence of potential strategies to protect against skeletal muscle wasting through inhibition of MuRF-1 and MAFbx expression will be explored.
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Affiliation(s)
- Oren Rom
- Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, P.O. Box 9649, Haifa, Israel.
| | - Abraham Z Reznick
- Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, P.O. Box 9649, Haifa, Israel
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19
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Zhao Y, Liu X, He Z, Niu X, Shi W, Ding JM, Zhang L, Yuan T, Li A, Yang W, Lu L. Essential role of proteasomes in maintaining self-renewal in neural progenitor cells. Sci Rep 2016; 6:19752. [PMID: 26804982 DOI: 10.1038/srep19752] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 12/17/2015] [Indexed: 11/29/2022] Open
Abstract
Protein turnover and homeostasis are regulated by the proteasomal system, which is critical for cell function and viability. Pluripotency of stem cells also relies on normal proteasomal activity that mitigates senescent phenotypes induced by intensive cell replications, as previously demonstrated in human bone marrow stromal cells. In this study, we investigated the role of proteasomes in self-renewal of neural progenitor cells (NPCs). Through both in vivo and in vitro analyses, we found that the expression of proteasomes was progressively decreased during aging. Likewise, proliferation and self-renewal of NPCs were also impaired in aged mice, suggesting that the down-regulation of proteasomes might be responsible for this senescent phenotype. Lowering proteasomal activity by loss-of-function manipulations mimicked the senescence of NPCs both in vitro and in vivo; conversely, enhancing proteasomal activity restored and improved self-renewal in aged NPCs. These results collectively indicate that proteasomes work as a key regulator in promoting self-renewal of NPCs. This potentially provides a promising therapeutic target for age-dependent neurodegenerative diseases.
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20
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Abstract
Ubiquitin (UB) is a highly conserved low molecular weight (8.5 kDa) protein. It consists of 76 amino acid residues and is found in all eukaryotic cells. The covalent linkage of UB to a variety of cellular proteins (ubiquitination) is one of the most common posttranslational modifications in eukaryotic cells. This modification generally regulates protein turnover and protects the cells from damaged or misfolded proteins. The polyubiquitination of proteins serves as a signal for degradation via the 26S proteasome pathway. UB is present in trace amounts in body fluids. Elevated levels of UB are described in the serum or plasma of patients under a variety of conditions. Extracellular UB is proposed to have pleiotropic roles including regulation of immune response, anti-inflammatory, and neuroprotective activities. CXCR4 is identified as receptor for extracellular UB in hematopoietic cells. Heart failure represents a major cause of morbidity and mortality in western society. Cardiac remodeling is a determinant of the clinical course of heart failure. The components involved in myocardial remodeling include-myocytes, fibroblasts, interstitium, and coronary vasculature. Increased sympathetic nerve activity in the form of norepinephrine is a common feature during heart failure. Acting via β-adrenergic receptor (β-AR), norepinephrine is shown to induce myocyte apoptosis and myocardial fibrosis. β-AR stimulation increases extracellular levels of UB in myocytes, and UB inhibits β-AR-stimulated increases in myocyte apoptosis and myocardial fibrosis. This review summarizes intracellular and extracellular functions of UB with particular emphasis on the role of extracellular UB in cardiac myocyte apoptosis and myocardial remodeling.
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Affiliation(s)
- Stephanie L C Scofield
- Department of Biomedical Sciences, East Tennessee State University, Johnson City, Tennessee, USA
| | - Parthiv Amin
- Department of Biomedical Sciences, East Tennessee State University, Johnson City, Tennessee, USA
| | - Mahipal Singh
- Department of Biomedical Sciences, East Tennessee State University, Johnson City, Tennessee, USA
| | - Krishna Singh
- Department of Biomedical Sciences, East Tennessee State University, Johnson City, Tennessee, USA; Center for Inflammation, Infectious Disease and Immunity, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, USA; James H. Quillen VA Medical Center, East Tennessee State University, Johnson City, Tennessee, USA.,Department of Medicine, Albany Medical College, Albany, New York, USA.,Pharmaceutical Research Institute, Albany College of Pharmacy and Health Sciences, Rensselaer, New York, USA
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21
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Joseph AM, Adhihetty PJ, Leeuwenburgh C. Beneficial effects of exercise on age-related mitochondrial dysfunction and oxidative stress in skeletal muscle. J Physiol 2015; 594:5105-23. [PMID: 26503074 DOI: 10.1113/jp270659] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 10/05/2015] [Indexed: 12/12/2022] Open
Abstract
Mitochondria are negatively affected by ageing leading to their inability to adapt to higher levels of oxidative stress and this ultimately contributes to the systemic loss of muscle mass and function termed sarcopenia. Since mitochondria are central mediators of muscle health, they have become highly sought-after targets of physiological and pharmacological interventions. Exercise is the only known strategy to combat sarcopenia and this is largely mediated through improvements in mitochondrial plasticity. More recently a critical role for mitochondrial turnover in preserving muscle has been postulated. Specifically, cellular pathways responsible for the regulation of mitochondrial turnover including biogenesis, dynamics and autophagy may become dysregulated during ageing resulting in the reduced clearance and accumulation of damaged organelles within the cell. When mitochondrial quality is compromised and homeostasis is not re-established, myonuclear cell death is activated and muscle atrophy ensues. In contrast, acute and chronic exercise attenuates these deficits, restoring mitochondrial turnover and promoting a healthier mitochondrial pool that leads to the preservation of muscle. Additionally, the magnitude of these exercise-induced mitochondrial adaptations is currently debated with several studies reporting a lower adaptability of old muscle relative to young, but the processes responsible for this diminished training response are unclear. Based on these observations, understanding the molecular details of how advancing age and exercise influence mitochondria in older muscle will provide invaluable insight into the development of exercise protocols that will maximize beneficial adaptations in the elderly. This information will also be imperative for future research exploring pharmacological targets of mitochondrial plasticity.
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Affiliation(s)
- Anna-Maria Joseph
- Department of Aging and Geriatric Research, Division of Biology of Aging, University of Florida, Gainesville, FL, 32611, USA.
| | - Peter J Adhihetty
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, 32611, USA
| | - Christiaan Leeuwenburgh
- Department of Aging and Geriatric Research, Division of Biology of Aging, University of Florida, Gainesville, FL, 32611, USA
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22
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Wagatsuma A, Shiozuka M, Takayama Y, Hoshino T, Mabuchi K, Matsuda R. Effects of ageing on expression of the muscle-specific E3 ubiquitin ligases and Akt-dependent regulation of Foxo transcription factors in skeletal muscle. Mol Cell Biochem 2016; 412:59-72. [PMID: 26590085 DOI: 10.1007/s11010-015-2608-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 11/14/2015] [Indexed: 12/11/2022]
Abstract
Controversy exists as to whether the muscle-specific E3 ubiquitin ligases MAFbx and MuRF1 are transcriptionally upregulated in the process of sarcopenia. In the present study, we investigated the effects of ageing on mRNA/protein expression of muscle-specific E3 ubiquitin ligases and Akt/Foxo signalling in gastrocnemius muscles of female mice. Old mice exhibited a typical sarcopenic phenotype, characterized by loss of muscle mass and strength, decreased amount of myofibrillar proteins, incidence of aberrant muscle fibres, and genetic signature to sarcopenia. Activation levels of Akt were lower in adult and old mice than in young mice. Consequently, Akt-mediated phosphorylation levels of Foxo1 and Foxo3 proteins were decreased. Nuclear levels of Foxo1 and Foxo3 proteins showed an overall increasing trend in old mice. MAFbx mRNA expression was decreased in old mice relative to adult mice, whereas MuRF1 mRNA expression was less affected by ageing. At the protein level, MAFbx was less affected by ageing, whereas MuRF1 was increased in old mice relative to adult mice, with ubiquitin-protein conjugates being increased with ageing. In conclusion, we provided evidence for no mRNA upregulation of muscle-specific E3 ubiquitin ligases and disconnection between their expression and Akt/Foxo signalling in sarcopenic mice. Their different responsiveness to ageing may reflect different roles in sarcopenia.
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23
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Salmerón C, Navarro I, Johnston IA, Gutiérrez J, Capilla E. Characterisation and expression analysis of cathepsins and ubiquitin-proteasome genes in gilthead sea bream (Sparus aurata) skeletal muscle. BMC Res Notes 2015; 8:149. [PMID: 25880457 PMCID: PMC4431372 DOI: 10.1186/s13104-015-1121-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 04/02/2015] [Indexed: 12/02/2022] Open
Abstract
Background The proteolytic enzymes involved in normal protein turnover in fish muscle are also responsible for post-mortem softening of the flesh and are therefore potential determinants of product quality. The main enzyme systems involved are calpains, cathepsins, and the ubiquitin-proteasome (UbP). In this study on Sparus aurata (Sa), the coding sequences of cathepsins (SaCTSB and SaCTSDb) and UbP family members (SaN3 and SaUb) were cloned from fast skeletal muscle, and their expression patterns were examined during ontogeny and in a fasting/re-feeding experiment. Results The amino acid sequences identified shared 66-100% overall identity with their orthologues in other vertebrates, with well conserved characteristic functional domains and catalytic residues. SaCTSDb showed phylogenetic, sequence and tissue distribution differences with respect to its paralogue SaCTSDa, previously identified in the ovary. Expression of gilthead sea bream cathepsins (B, L, Da, Db) and UbP members (N3, Ub, MuRF1 and MAFbx) in fast skeletal muscle was determined at three different life-history stages and in response to fasting and re-feeding in juveniles. Most of the proteolytic genes analysed were significantly up-regulated during fasting, and down-regulated with re-feeding and, between the fingerling (15 g) and juvenile/adult stages (~50/500 g), consistent with a decrease in muscle proteolysis in both later contexts. In contrast, SaCTSDa and SaMuRF1 expression was relatively stable with ontogeny and SaUb had higher expression in fingerlings and adults than juveniles. Conclusions The data obtained in the present study suggest that cathepsins and UbP genes in gilthead sea bream are co-ordinately regulated during ontogeny to control muscle growth, and indicate that feeding regimes can modulate their expression, providing a potential dietary method of influencing post-mortem fillet tenderisation, and hence, product quality. Electronic supplementary material The online version of this article (doi:10.1186/s13104-015-1121-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Cristina Salmerón
- Department of Physiology and Immunology, Faculty of Biology, University of Barcelona, Av. Diagonal 643, Barcelona, 08028, Spain.
| | - Isabel Navarro
- Department of Physiology and Immunology, Faculty of Biology, University of Barcelona, Av. Diagonal 643, Barcelona, 08028, Spain.
| | - Ian A Johnston
- Scottish Oceans Institute, School of Biology, University of St Andrews, St Andrews Fife, KY16 8LB, Scotland, UK.
| | - Joaquim Gutiérrez
- Department of Physiology and Immunology, Faculty of Biology, University of Barcelona, Av. Diagonal 643, Barcelona, 08028, Spain.
| | - Encarnación Capilla
- Department of Physiology and Immunology, Faculty of Biology, University of Barcelona, Av. Diagonal 643, Barcelona, 08028, Spain.
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24
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Khor SC, Abdul Karim N, Ngah WZ, Yusof YA, Makpol S. Vitamin E in sarcopenia: current evidences on its role in prevention and treatment. Oxid Med Cell Longev 2014; 2014:914853. [PMID: 25097722 DOI: 10.1155/2014/914853] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 06/06/2014] [Indexed: 01/01/2023]
Abstract
Sarcopenia is a geriatric syndrome that is characterized by gradual loss of muscle mass and strength with increasing age. Although the underlying mechanism is still unknown, the contribution of increased oxidative stress in advanced age has been recognized as one of the risk factors of sarcopenia. Thus, eliminating reactive oxygen species (ROS) can be a strategy to combat sarcopenia. In this review, we discuss the potential role of vitamin E in the prevention and treatment of sarcopenia. Vitamin E is a lipid soluble vitamin, with potent antioxidant properties and current evidence suggesting a role in the modulation of signaling pathways. Previous studies have shown its possible beneficial effects on aging and age-related diseases. Although there are evidences suggesting an association between vitamin E and muscle health, they are still inconclusive compared to other more extensively studied chronic diseases such as neurodegenerative diseases and cardiovascular diseases. Therefore, we reviewed the role of vitamin E and its potential protective mechanisms on muscle health based on previous and current in vitro and in vivo studies.
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25
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Abstract
Autoimmune diseases are characterized by the production of antibodies against self-antigens and generally arise from a failure of central or peripheral tolerance. However, these diseases may develop when newly appearing antigens are not recognized as self by the immune system. The mechanism by which some antigens are “invisible” to the immune system is not completely understood. Apoptotic and complement system defects or autophagy imbalance can generate this antigenic autoreactivity. Under particular circumstances, cellular debris containing autoreactive antigens can be recognized by innate immune receptors or other sensors and can eventually lead to autoimmunity. Ubiquitination may be one of the mechanisms protecting autoreactive antigens from the immune system that, if disrupted, can lead to autoimmunity. Ubiquitination is an essential post-translational modification used by cells to target proteins for degradation or to regulate other intracellular processes. The level of ubiquitination is regulated during T cell tolerance and apoptosis and E3 ligases have emerged as a crucial signaling pathway for the regulation of T cell tolerance toward self-antigens. I propose here that an unrecognized role of ubiquitin and ubiquitin-like proteins could be to render intracellular or foreign antigens (present in cellular debris resulting from apoptosis, complement system, or autophagy defects) invisible to the immune system in order to prevent the development of autoimmunity.
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Affiliation(s)
- Robert Weil
- Unité de Signalisation Moléculaire et Activation Cellulaire, CNRS URA 2582, Institut Pasteur , Paris , France
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26
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Abstract
Sarcopenia is one of the leading causes of disability in the elderly. Despite the growing prevalence of sarcopenia, the molecular mechanisms that control aging-related changes in muscle mass are not fully understood. The ubiquitin proteasome system is one of the major pathways that regulate muscle protein degradation, and this system plays a central role in controlling muscle size. Atrogin-1 and MuRF-1 are two E3 ubiquitin ligases that are important regulators of ubiquitin-mediated protein degradation in skeletal muscle. In this review, we will discuss: (i) aging-related changes to skeletal muscle structure and function; (ii) the regulation of protein synthesis and protein degradation by IGF-1, TGF-β, and myostatin, with emphasis on the control of atrogin-1 and MuRF-1 expression; and (iii) the potential for modulating atrogin-1 and MuRF-1 expression to treat or prevent sarcopenia.
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Affiliation(s)
- Jonathan P Gumucio
- Department of Orthopaedic Surgery, University of Michigan Medical School, 109 Zina Pitcher Place, BSRB 2017, Ann Arbor, MI, 48109-2200, USA
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27
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Hasan KMM, Rahman MS, Arif KMT, Sobhani ME. Psychological stress and aging: role of glucocorticoids (GCs). Age (Dordr) 2012; 34:1421-1433. [PMID: 21971999 PMCID: PMC3528378 DOI: 10.1007/s11357-011-9319-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Accepted: 09/19/2011] [Indexed: 05/31/2023]
Abstract
Psychological stress has extreme adverse consequences on health. However, the molecular mechanisms that mediate and accelerate the process of aging due to stress hormone are not well defined. This review has focused on diverse molecular paths that come out in response to chronic psychological stress via releasing of excessive glucocorticoids (GCs), involved in the aging process. GCs suppress transcription of nuclear cell adhesion molecules which impair synaptic plasticity, memory formation, and cognitive ability. Again, GCs promote muscle atrophy by means of motivating ubiquitin proteasome system and can repress muscle protein synthesis by inhibition of PI3-kinase/Akt pathway. GCs also inhibit interleukin-2 synthesis through suppressing T cell receptor signal that leads to loss of T cell activation, proliferation, and B-cell activation. Moreover, GCs increase the expression of collagenase-3, RANK ligand, and colony stimulating factor-1 that induce bone resorption. In general, stress-induced GCs can play causal role for aging and age-related disorders.
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Affiliation(s)
- K. M. Mehedi Hasan
- Biotechnology and Genetic Engineering Discipline, Khulna University, Khulna, 9208 Bangladesh
| | - Md. Shaifur Rahman
- Biotechnology and Genetic Engineering Discipline, Khulna University, Khulna, 9208 Bangladesh
| | - K. M. T. Arif
- Biotechnology and Genetic Engineering Discipline, Khulna University, Khulna, 9208 Bangladesh
| | - Mahbub E. Sobhani
- Biotechnology and Genetic Engineering Discipline, Khulna University, Khulna, 9208 Bangladesh
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Peterson CM, Johannsen DL, Ravussin E. Skeletal muscle mitochondria and aging: a review. J Aging Res 2012; 2012:194821. [PMID: 22888430 DOI: 10.1155/2012/194821] [Citation(s) in RCA: 189] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Accepted: 05/21/2012] [Indexed: 12/12/2022] Open
Abstract
Aging is characterized by a progressive loss of muscle mass and muscle strength. Declines in skeletal muscle mitochondria are thought to play a primary role in this process. Mitochondria are the major producers of reactive oxygen species, which damage DNA, proteins, and lipids if not rapidly quenched. Animal and human studies typically show that skeletal muscle mitochondria are altered with aging, including increased mutations in mitochondrial DNA, decreased activity of some mitochondrial enzymes, altered respiration with reduced maximal capacity at least in sedentary individuals, and reduced total mitochondrial content with increased morphological changes. However, there has been much controversy over measurements of mitochondrial energy production, which may largely be explained by differences in approach and by whether physical activity is controlled for. These changes may in turn alter mitochondrial dynamics, such as fusion and fission rates, and mitochondrially induced apoptosis, which may also lead to net muscle fiber loss and age-related sarcopenia. Fortunately, strategies such as exercise and caloric restriction that reduce oxidative damage also improve mitochondrial function. While these strategies may not completely prevent the primary effects of aging, they may help to attenuate the rate of decline.
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Sakuma K, Yamaguchi A. Sarcopenia and cachexia: the adaptations of negative regulators of skeletal muscle mass. J Cachexia Sarcopenia Muscle 2012; 3:77-94. [PMID: 22476916 PMCID: PMC3374017 DOI: 10.1007/s13539-011-0052-4] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Accepted: 11/08/2011] [Indexed: 12/25/2022] Open
Abstract
Recent advances in our understanding of the biology of muscle, and how anabolic and catabolic stimuli interact to control muscle mass and function, have led to new interest in the pharmacological treatment of muscle wasting. Loss of muscle occurs as a consequence of several chronic diseases (cachexia) as well as normal aging (sarcopenia). Although many negative regulators [Atrogin-1, muscle ring finger-1, nuclear factor-kappaB (NF-κB), myostatin, etc.] have been proposed to enhance protein degradation during both sarcopenia and cachexia, the adaptation of mediators markedly differs among these conditions. Sarcopenic and cachectic muscles have been demonstrated to be abundant in myostatin- and apoptosis-linked molecules. The ubiquitin-proteasome system (UPS) is activated during many different types of cachexia (cancer cachexia, cardiac heart failure, chronic obstructive pulmonary disease), but not many mediators of the UPS change during sarcopenia. NF-κB signaling is activated in cachectic, but not in sarcopenic, muscle. Some studies have indicated a change of autophagic signaling during both sarcopenia and cachexia, but the adaptation remains to be elucidated. This review provides an overview of the adaptive changes in negative regulators of muscle mass in both sarcopenia and cachexia.
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Affiliation(s)
- Kunihiro Sakuma
- Research Center for Physical Fitness, Sports and Health, Toyohashi University of Technology, 1-1 Hibarigaoka, Tenpaku-cho, Toyohashi, 441-8580, Japan,
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Vazeille E, Slimani L, Claustre A, Magne H, Labas R, Béchet D, Taillandier D, Dardevet D, Astruc T, Attaix D, Combaret L. Curcumin treatment prevents increased proteasome and apoptosome activities in rat skeletal muscle during reloading and improves subsequent recovery. J Nutr Biochem 2012; 23:245-51. [DOI: 10.1016/j.jnutbio.2010.11.021] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Revised: 10/20/2010] [Accepted: 11/29/2010] [Indexed: 11/22/2022]
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Chaudhary P, Suryakumar G, Prasad R, Singh SN, Ali S, Ilavazhagan G. Chronic hypobaric hypoxia mediated skeletal muscle atrophy: role of ubiquitin–proteasome pathway and calpains. Mol Cell Biochem 2012; 364:101-13. [DOI: 10.1007/s11010-011-1210-x] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Accepted: 12/21/2011] [Indexed: 12/28/2022]
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Saini V, Staren DM, Ziarek JJ, Nashaat ZN, Campbell EM, Volkman BF, Marchese A, Majetschak M. The CXC chemokine receptor 4 ligands ubiquitin and stromal cell-derived factor-1α function through distinct receptor interactions. J Biol Chem 2011; 286:33466-77. [PMID: 21757744 PMCID: PMC3190899 DOI: 10.1074/jbc.m111.233742] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Revised: 07/11/2011] [Indexed: 01/21/2023] Open
Abstract
Recently, we identified extracellular ubiquitin as an endogenous CXC chemokine receptor (CXCR) 4 agonist. However, the receptor selectivity and molecular basis of the CXCR4 agonist activity of ubiquitin are unknown, and functional consequences of CXCR4 activation with ubiquitin are poorly defined. Here, we provide evidence that ubiquitin and the cognate CXCR4 ligand stromal cell-derived factor (SDF)-1α do not share CXCR7 as a receptor. We further demonstrate that ubiquitin does not utilize the typical two-site binding mechanism of chemokine-receptor interactions, in which the receptor N terminus is important for ligand binding. CXCR4 activation with ubiquitin and SDF-1α lead to similar Gα(i)-responses and to a comparable magnitude of phosphorylation of ERK-1/2, p90 ribosomal S6 kinase-l and Akt, although phosphorylations occur more transiently after activation with ubiquitin. Despite the similarity of signal transduction events after activation of CXCR4 with both ligands, ubiquitin possesses weaker chemotactic activity than SDF-lα in cell migration assays and does not interfere with productive entry of HIV-1 into P4.R5 multinuclear activation of galactosidase indicator cells. Unlike SDF-1α, ubiquitin lacks interactions with an N-terminal CXCR4 peptide in NMR spectroscopy experiments. Binding and signaling studies in the presence of antibodies against the N terminus and extracellular loops 2/3 of CXCR4 confirm that the ubiquitin CXCR4 interaction is independent of the N-terminal receptor domain, whereas blockade of extracellular loops 2/3 prevents receptor binding and activation. Our findings define ubiquitin as a CXCR4 agonist, which does not interfere with productive cellular entry of HIV-1, and provide new mechanistic insights into interactions between CXCR4 and its natural ligands.
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Affiliation(s)
- Vikas Saini
- From the Department of Surgery, Burn and Shock Trauma Institute, and
| | - Daniel M. Staren
- From the Department of Surgery, Burn and Shock Trauma Institute, and
| | - Joshua J. Ziarek
- the Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | | | | | - Brian F. Volkman
- the Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Adriano Marchese
- Molecular Pharmacology & Therapeutics, Loyola University Chicago Stritch School of Medicine, Maywood, Illinois 60153 and
| | - Matthias Majetschak
- From the Department of Surgery, Burn and Shock Trauma Institute, and
- Molecular Pharmacology & Therapeutics, Loyola University Chicago Stritch School of Medicine, Maywood, Illinois 60153 and
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Altun M, Besche HC, Overkleeft HS, Piccirillo R, Edelmann MJ, Kessler BM, Goldberg AL, Ulfhake B. Muscle wasting in aged, sarcopenic rats is associated with enhanced activity of the ubiquitin proteasome pathway. J Biol Chem 2010; 285:39597-608. [PMID: 20940294 DOI: 10.1074/jbc.m110.129718] [Citation(s) in RCA: 162] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Among the hallmarks of aged organisms are an accumulation of misfolded proteins and a reduction in skeletal muscle mass ("sarcopenia"). We have examined the effects of aging and dietary restriction (which retards many age-related changes) on components of the ubiquitin proteasome system (UPS) in muscle. The hindlimb muscles of aged (30 months old) rats showed a marked loss of muscle mass and contained 2-3-fold higher levels of 26S proteasomes than those of adult (4 months old) controls. 26S proteasomes purified from muscles of aged and adult rats showed a similar capacity to degrade peptides, proteins, and an ubiquitylated substrate, but differed in levels of proteasome-associated proteins (e.g. the ubiquitin ligase E6AP and deubiquitylating enzyme USP14). Also, the activities of many other deubiquitylating enzymes were greatly enhanced in the aged muscles. Nevertheless, their content of polyubiquitylated proteins was higher than in adult animals. The aged muscles contained higher levels of the ubiquitin ligase CHIP, involved in eliminating misfolded proteins, and MuRF1, which ubiquitylates myofibrillar proteins. These muscles differed from ones rapidly atrophying due to disease, fasting, or disuse in that Atrogin-1/MAFbx expression was low and not inducible by glucocorticoids. Thus, the muscles of aged rats showed many adaptations indicating enhanced proteolysis by the UPS, which may enhance their capacity to eliminate misfolded proteins and seems to contribute to the sarcopenia. Accordingly, dietary restriction decreased or prevented the aging-associated increases in proteasomes and other UPS components and reduced muscle wasting.
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Affiliation(s)
- Mikael Altun
- Department of Neuroscience, Karolinska Institutet, 17177 Stockholm, Sweden.
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Majetschak M. Extracellular ubiquitin: immune modulator and endogenous opponent of damage-associated molecular pattern molecules. J Leukoc Biol 2010; 89:205-19. [PMID: 20689098 DOI: 10.1189/jlb.0510316] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Ubiquitin is a post-translational protein modifier and plays essential roles in all aspects of biology. Although the discovery of ubiquitin introduced this highly conserved protein as a molecule with extracellular actions, the identification of ubiquitin as the ATP-dependent proteolysis factor 1 has focused subsequent research on its important intracellular functions. Little attention has since been paid to its role outside of the cell. During recent years, multiple observations suggest that extracellular ubiquitin can modulate immune responses and that exogenous ubiquitin has therapeutic potential to attenuate exuberant inflammation and organ injury. These observations have not been integrated into a comprehensive assessment of its possible role as an endogenous immune modulator. This review recapitulates the current knowledge about extracellular ubiquitin and discusses an emerging facet of its role in biology during infectious and noninfectious inflammation. The synopsis of these data along with the recent identification of ubiquitin as a CXCR4 agonist suggest that extracellular ubiquitin may have pleiotropic roles in the immune system and functions as an endogenous opponent of DAMPs. Functions of extracellular ubiquitin could constitute an evolutionary conserved control mechanism aimed to balance the immune response and prevent exuberant inflammation. Further characterization of its mechanism of action and cellular signaling pathways is expected to provide novel insights into the regulation of the innate immune response and opportunities for therapeutic interventions.
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Affiliation(s)
- Matthias Majetschak
- Loyola University Chicago, Stritch School of Medicine, Maywood, IL 60153, USA.
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Ferreira R, Vitorino R, Neuparth MJ, Appell H, Duarte JA, Amado F. Proteolysis activation and proteome alterations in murine skeletal muscle submitted to 1 week of hindlimb suspension. Eur J Appl Physiol 2009; 107:553-63. [DOI: 10.1007/s00421-009-1151-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/28/2009] [Indexed: 12/16/2022]
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Abstract
PURPOSE OF REVIEW To understand age-related changes in proteolysis and apoptosis in skeletal muscle in relation to oxidative stress and mitochondrial alterations. RECENT FINDINGS During aging, a progressive loss of muscle mass (sarcopenia) has been described in both human and rodents. Sarcopenia is attributable to an imbalance between protein synthesis and degradation or between apoptosis and regeneration processes or both. Major age-dependent alterations in muscle proteolysis are a lack of responsiveness of the ubiquitin-proteasome-dependent proteolytic pathway to anabolic and catabolic stimuli and alterations in the regulation of autophagy. In addition, increased oxidative stress leads to the accumulation of damaged proteins, which are not properly eliminated, aggregate, and in turn impair proteolytic activities. Finally, the mitochondria-associated apoptotic pathway may be activated. These age-induced changes may contribute to sarcopenia and decreased ability of old individuals to recover from stress. SUMMARY Alterations in proteasome-dependent or lysosomal proteolysis, increased oxidative stress, mitochondrial dysfunction, and apoptosis presumably contribute to the development of sarcopenia.
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Affiliation(s)
- Lydie Combaret
- INRA, Centre Clermont-Ferrand-Theix, UMR1019, Unité Nutrition Humaine, St. Genès Champanelle, France.
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Hepple RT, Qin M, Nakamoto H, Goto S. Caloric restriction optimizes the proteasome pathway with aging in rat plantaris muscle: implications for sarcopenia. Am J Physiol Regul Integr Comp Physiol 2008; 295:R1231-7. [DOI: 10.1152/ajpregu.90478.2008] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To gain insight into the significance of alterations in the proteasome pathway for sarcopenia and its attenuation by calorie restriction, we examined protein oxidation and components of the proteasome pathway in plantaris muscle in 8-, 30-, and 35-mo-old ad libitum-fed (AL) rats; and in 8-, 35-, and 40-mo-old calorie-restricted (CR) rats. We hypothesized that CR rats would exhibit a lesser accumulation of protein carbonyls with aging and that this would be associated with a better maintenance of skeletal muscle proteasome activity and function with aging. Consistent with this view, whereas AL rats had a significant increase in protein carbonylation with aging, there was no such increase in CR rats. Protein levels of the ubiquitin ligases MuRF1 and MAFbx increased similarly with aging in both AL and CR rats. On the other hand, chymotrypsin-like activity of the proteasome increased with aging more gradually in CR rats, and this increase was paralleled by increases in the expression of the C2 subunit in both groups, suggesting that differences in activity were not related to differences in proteasome function with aging. Interestingly, the plot of muscle mass vs. proteasome activity showed that the oldest animals in both diets had a lower muscle mass than would be predicted by their proteasome activity, suggesting that other factors explain the acceleration of sarcopenia at advanced age. Since calorie restriction better protects skeletal muscle function than muscle mass with aging (Hepple RT, Baker DJ, Kaczor JJ, Krause DJ, FASEB J 19: 1320–1322, 2005), and our current results show that this protection of function is associated with a prevention of oxidative protein damage accumulation, we suggest that calorie restriction optimizes the proteasome pathway to preserve skeletal muscle function at the expense of modest muscle atrophy.
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Bossola M, Pacelli F, Costelli P, Tortorelli A, Rosa F, Doglietto GB. Proteasome activities in the rectus abdominis muscle of young and older individuals. Biogerontology 2008; 9:261-8. [PMID: 18330717 DOI: 10.1007/s10522-008-9135-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2008] [Accepted: 02/25/2008] [Indexed: 10/22/2022]
Abstract
Sarcopenia is one of the most striking effects of age, the causes and the pathogenic mechanisms being largely unknown. Unfortunately, there is limited information on the effect of aging on muscle protein breakdown in basal conditions. The present study aimed at investigating if skeletal muscle ubiquitn mRNA levels and proteasome activities vary with age in healthy individuals. Ub mRNA levels were measured by northern blot analysis whereas proteasome activities were determined by evaluating the cleavage of specific fluorogenic substrates in the rectus abdominis muscle of 14 healthy male individuals. Patients were divided in three groups according to the age: (1) 20-30 years (N = 3); (2) 31-64 years (N = 5); (3) > or = 65 years (N = 6). Quantitation of the ubiquitin mRNA levels (expressed in arbitrary units) (mean (SD) showed no differences among the three groups of age (20-30 years: 1352 +/- 441; 31-64 years: 1324 +/- 439; > or = 65 years: 884 +/- 400; P = 0.33). The correlation between age and muscle ubiquitin mRNA levels was not statistically significant (r = -0.4, P = 0.26). The three proteasome activities, chymotrypsin-like (CTL), trypsin-like (TL) and peptidyl-gutamyl-peptidase (PGP), expressed as nkatal x 10(-3)/mg protein, were similar in the three groups of patients stratified according to the age. There was no correlation between age with either CTL (r = 0.22, P = 0.4), PGP (r = 0.002, P = 0.9), and TL (r = 0.28, P = 0.33) activities. In conclusion, the present study shows that the skeletal muscle proteasome activities do not differ with age in healthy male individuals.
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Affiliation(s)
- Maurizio Bossola
- Istituto di Clinica Chirurgica, Università Cattolica del Sacro Cuore, Largo A. Gemelli, 8, 00168, Rome, Italy.
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Abstract
In all cells, protein degradation is a constant, ongoing process that is critical for cell survival and repair. The ubiquitin/proteasome pathway (UPP) is the major proteolytic pathway that degrades intracellular proteins in a regulated manner. It plays critical roles in many cellular processes and diseases. Disruption of the UPP is particularly relevant to pathophysiological conditions that provoke the accumulation of aberrant proteins, such as in aging as well as in a variety of neurodegenerative disorders including Alzheimer's and Parkinson's diseases. For unknown reasons, most of these neurodegenerative disorders that include familial and sporadic cases exhibit a late onset. It is possible that these neurodegenerative conditions exhibit a late onset because proteasome activity decreases with aging. Aging-dependent impairment in proteolysis mediated by the proteasome may have profound ramifications for cell viability. It can lead to the accumulation of modified, potentially toxic proteins in cells and can cause cell injury or premature cell death by apoptosis or necrosis. While it is accepted that aging affects UPP function, the question is why does aging cause a decline in regulated protein degradation by the UPP? Herein, we review some of the properties of the UPP and mechanisms mediating its age-dependent impairment. We also discuss the relevance of these findings leading to a model that proposes that UPP dysfunction may be one of the milestones of aging.
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Affiliation(s)
- Vita A Vernace
- Department of Biological Sciences, Hunter College of the City University of New York, New York, NY 10021, USA
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Dargelos E, Brulé C, Combaret L, Hadj-Sassi A, Dulong S, Poussard S, Cottin P. Involvement of the calcium-dependent proteolytic system in skeletal muscle aging. Exp Gerontol 2007; 42:1088-98. [PMID: 17937979 DOI: 10.1016/j.exger.2007.08.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2007] [Revised: 08/28/2007] [Accepted: 08/30/2007] [Indexed: 12/25/2022]
Abstract
Aging is associated with a progressive and involuntary loss of muscle mass also known as sarcopenia. This condition represents a major public health concern with high socio-economics implications. Although sarcopenia is well documented, the aetiology of this condition still remains poorly understood. Calpains are ubiquitous proteases regulated in part by a specific inhibitor, calpastatin. They are well known to have major implications in muscle growth and differentiation. The aim of the present study was to determine if this proteolytic system could be involved in the phenotype associated with sarcopenia. Calpains and calpastatin levels, subcellular distributions and activities were compared between muscles from 3 and 24 months old rats. Altogether, the results we obtained showed an overall increase in calpain activities associated with muscle aging. These findings suggest that the calcium-dependent proteolytic system is indeed involved in sarcopenia.
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Affiliation(s)
- Elise Dargelos
- Université Bordeaux I, INRA USC 2009, Unité Protéolyse Croissance et Développement Musculaire, ISTAB, avenue des facultés, 33405 Talence Cedex, France.
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Mori S, Tokuyama K. Variation in ACE activity affects myogenic differentiation in C2C12 cells. Biochem Biophys Res Commun 2006; 353:369-75. [PMID: 17188239 DOI: 10.1016/j.bbrc.2006.12.056] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2006] [Accepted: 12/05/2006] [Indexed: 10/23/2022]
Abstract
Variation in ACE activity is related to affect the skeletal muscle function. To elucidate the mechanism by which ACE affects skeletal muscle function, we examined the effects of loss and gain of ACE activity on myogenic differentiation in C2C12 myoblasts. The treatment of captopril, an ACE inhibitor, in differentiating cells significantly induced the up-regulation of myosin heavy chain, and the hypertrophic myotubes. In addition, an AT2 antagonist PD123319, not AT1 antagonist losartan, induced the up-regulation of myosin heavy chain. On the other hand, overexpression of ACE induced the down-regulation of myosin heavy chain. These results suggest that ACE negatively regulate the myogenesis through the mechanism at least in part via production of angiotensin II followed by its binding to AT2 receptor.
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Affiliation(s)
- Shuuichi Mori
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8574, Japan
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Grillari J, Katinger H, Voglauer R. Aging and the ubiquitinome: traditional and non-traditional functions of ubiquitin in aging cells and tissues. Exp Gerontol 2006; 41:1067-79. [PMID: 17052881 DOI: 10.1016/j.exger.2006.07.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2006] [Revised: 07/13/2006] [Accepted: 07/18/2006] [Indexed: 01/01/2023]
Abstract
Ubiquitination of endogenous proteins is one of the key regulatory steps of protein degradation followed by regulation of proteasome activity. During the last years evidence has increased that proteasome activity is decreased during the aging process in various model systems and that these changes might be causally related to aging and aging associated diseases. Since in most instances ubiquitination is the primary event in target selection, the system of ubiquitination and deubiquitination might be of similar importance. Furthermore, ubiquitination and proteasomal degradation are not completely congruent, since ubiquitination also confers functions different from giving "the kiss of death" to proteins. Depending on mono- and polyubiquitination and on how ubiquitin chains are linked together, ubiquitination is involved in transcriptional regulation, receptor internalization, DNA repair, and stabilization of protein complexes. This review is therefore the first to summarize the current knowledge regarding the ubiquitinome and the underlying ubiquitin ligases and deubiquitinating enzymes in replicative senescence, tissue aging as well as in segmental progeroid syndromes and to discuss potential causes and consequences for aging.
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Affiliation(s)
- Johannes Grillari
- Department of Biotechnology, Institute of Applied Microbiology, University of Natural Resources and Applied Life Sciences, Vienna Muthgasse 18, A-1190 Vienna, Austria.
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Clavel S, Coldefy AS, Kurkdjian E, Salles J, Margaritis I, Derijard B. Atrophy-related ubiquitin ligases, atrogin-1 and MuRF1 are up-regulated in aged rat Tibialis Anterior muscle. Mech Ageing Dev 2006; 127:794-801. [PMID: 16949134 DOI: 10.1016/j.mad.2006.07.005] [Citation(s) in RCA: 152] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2006] [Revised: 06/07/2006] [Accepted: 07/17/2006] [Indexed: 01/17/2023]
Abstract
A phenotypic feature of aging is skeletal muscle wasting. It is characterized by a loss of muscle mass and strength. Age-related loss of muscle mass occurs through a reduction in the rate of protein synthesis, an increase in protein degradation or a combination of both. However, the underlying mechanism is still poorly understood. To test the hypothesis that the ubiquitin-proteasome pathway contributes to this phenomenon, we studied MuRF1 and atrogin-1 expression in Tibialis Anterior muscle of aged rats. These two E3 ligases are considered as sensitive markers of muscle protein degradation by the ubiquitin-proteasome system. Our results revealed that, in skeletal muscle of aged rats, the decline in muscle mass is accompanied by an increase in the level of oxidized proteins and ubiquitin conjugates (90%) whereas the functionality of the proteasome remains constant compared to young rats. Furthermore, the level of both MuRF1 and atrogin-1 mRNA is markedly up-regulated in aged muscle (respectively x2 and x2.5). Taken together these data argue for the involvement of the ubiquitin-proteasome pathway in sarcopenia of fast-twitch muscle, in particular through increased expression of MuRF1 and atrogin-1. Moreover, we observed a decrease in the IGF-1/Akt signalling pathways and elevated level of TNFalpha mRNA in aged rat muscle. Therefore, IGF-1/Akt and TNFalpha represent potential mediators implicated in the regulation of MuRF1 and atrogin-1 genes during aging.
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Affiliation(s)
- Stephan Clavel
- Laboratoire de Physiologie Cellulaire et Moléculaire, CNRS UMR 6548, Faculté des Sciences, Université de Nice Sophia Antipolis, 28 Avenue Valrose, 06108 Nice Cedex 2, France
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Deruisseau KC, Kavazis AN, Powers SK. Selective downregulation of ubiquitin conjugation cascade mRNA occurs in the senescent rat soleus muscle. Exp Gerontol 2006; 40:526-31. [PMID: 15963672 DOI: 10.1016/j.exger.2005.04.005] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2005] [Revised: 04/11/2005] [Accepted: 04/14/2005] [Indexed: 11/18/2022]
Abstract
Aging-related alterations of the ubiquitin proteasome pathway (UPP) have been reported in locomotor skeletal muscle. Specifically, declines in proteasome activity have been observed in the soleus of senescent animals compared to the soleus of young controls. However, the influence of aging on the mRNA levels of key components within the ubiquitin conjugation cascade (UCC) remains unknown. We hypothesized that aged soleus muscle would exhibit downregulated expression of select UCC mRNA and decreased levels of ubiquitin-protein conjugates. To test this postulate, we harvested soleus muscles from 6 and 24-26 month old Fisher 344 rats. Aging resulted in a decline in mRNA expression of two key UCC components in soleus muscle; ubiquitin conjugating enzyme E2(14k) (E2(14k)) and muscle ring finger-1 (MuRF1). Surprisingly, no age-related differences existed in the total content of endogenous ubiquitin-protein conjugates in the soleus muscle. Nonetheless, a selective decrease in the level of ubiquitin-protein conjugates ( approximately 30kDa) was detected in the soleus of senescent animals. These results indicate that the soleus muscle displays a differential mRNA response of select UCC components to aging. Furthermore, the decline in E2(14k) and MuRF1 mRNA levels may contribute to altered substrate degradation by the UCC in the soleus muscle of senescent rats.
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Affiliation(s)
- Keith C Deruisseau
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL 32611, USA
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Singh S, Khar A. Activation of NFkappaB and Ub-proteasome pathway during apoptosis induced by a serum factor is mediated through the upregulation of the 26S proteasome subunits. Apoptosis 2006; 11:845-59. [PMID: 16532374 DOI: 10.1007/s10495-006-5878-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
We have been investigating differential gene expression associated with apoptosis in AK-5 cells (a spontaneously regressing rat histiocytoma) and have observed catalytic subunits beta 7 and alpha 5 of the 26S proteasome and ubiquitin to be upregulated during apoptosis induced by a variety of agents. The observed elevation in gene expression was parallel to a comparable increase in the cytosolic protein expression of the proteasome and ubiquitin and a markedly amplified increase in the proteasome activity. Inhibition of the increase in gene expression resulted in the inhibition of the rise in the proteasome activity subsequently leading to an inhibition of apoptosis. Similarly, pretreatment with proteasome inhibitors, MG132 and lactacystin, resulted in a significant inhibition of apoptosis pointing to the requirement of a highly active protein degradation machinery during apoptosis. The apoptosis inhibitory effect of the proteasome inhibitors involved an inhibition of the activation of various initiator and effector caspases but was independent of any changes in the mitochondrial membrane depolarization and cytochrome c release associated with apoptosis. Inhibition of proteasome activity or its upstream PI3 kinase activity inhibited NFkappaB translocation thereby suppressing apoptosis, which highlights the requirement of NFkappaB activation for completion of apoptosis in AK-5 cells. Hence, the apoptosis associated induction of the Ub-proteasome pathway components and the proteasome activity suggests that the proteasome, in its capacity as an efficient protein degradation complex, plays an important role in the successful execution of apoptosis.
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Affiliation(s)
- S Singh
- Centre for Cellular & Molecular Biology, Uppal Road, Hyderabad 500 007, India
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Kaczor JJ, Ziolkowski W, Antosiewicz J, Hac S, Tarnopolsky MA, Popinigis J. The effect of aging on anaerobic and aerobic enzyme activities in human skeletal muscle. J Gerontol A Biol Sci Med Sci 2006; 61:339-44. [PMID: 16611699 DOI: 10.1093/gerona/61.4.339] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The effect of aging on metabolic enzyme activity remains controversial, possibly due to physical activity differences. We examined the effect of aging on the enzyme activity for anaerobic and aerobic pathways in nonweight-bearing human skeletal muscle from relatively sedentary males. The muscle obliquus internus abdominis was analyzed for anaerobic (creatine kinase, adenylate kinase, and lactate dehydrogenase) and aerobic (2-oxoglutarate dehydrogenase and carnitine palmitoyltransferase) enzyme activities in two groups: middle-aged (29-54 years) and older (61-74 years) adults. All enzyme activities were lower in older versus middle-aged adults when results were expressed as muscle wet weight (p <.05). When activity was expressed relative to the protein content, only lactate dehydrogenase remained significantly lower in older versus middle-aged adults (p <.001). In conclusion, some of the reduction in muscle performance in older adults may be due to lower activity of the anaerobic and aerobic enzymes as well as protein content, not solely due to a decrease in physical activity.
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Affiliation(s)
- Jan J Kaczor
- Department of Biochemistry, J. Sniadecki Academy of Physical Education and Sport, Gdansk, Poland.
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Rice KM, Blough ER. Sarcopenia-related apoptosis is regulated differently in fast- and slow-twitch muscles of the aging F344/N x BN rat model. Mech Ageing Dev 2006; 127:670-9. [PMID: 16678239 DOI: 10.1016/j.mad.2006.03.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2005] [Revised: 03/07/2006] [Accepted: 03/22/2006] [Indexed: 01/22/2023]
Abstract
Age-related decreases in muscle mass have been associated with the loss of myonuclei, possibly through a mechanism involving mitochondria. It is unclear if age-related apoptotic mechanisms vary by fiber type. Here we investigate indices of apoptosis along with the regulation of apoptotic mediators in the extensor digitorum longus (EDL) and soleus of adult (6 month), old (30 month), and very old (36 month) Fischer 344/NNiaHSD x Brown Norway/BiNia (F344/N x BN) rats. Compared to 6-month muscles, aged muscles exhibited decreases in muscle mass along with increases in the number of nuclei staining positively for DNA fragmentation. The expression of Bax, Bcl-2, caspase-3 and caspase-9 was regulated differently with aging between muscle types and in a manner not consistent with mitochondria-mediated apoptosis. To investigate the potential of calpain involvement in age-related myonuclear loss, the calpain-dependent cleavage of alpha-fodrin was examined. The proteolytic cleavage of alpha-fodrin by calpains was increased in both muscles with only the 36-month soleus exhibiting increased caspase-dependent alpha-fodrin cleavage. Taken together, these data suggest that apoptotic regulatory events differ between fiber types in the aging F344/N x BN and that mitochondrial-dependent apoptosis pathways may not play a primary role in the loss of muscle nuclei with aging.
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Affiliation(s)
- K M Rice
- Department of Biological Sciences, Marshall University, Huntington, WV 25755-1090, United States
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Abstract
Continuous turnover of intracellular proteins is essential for the maintenance of cellular homeostasis and for the regulation of multiple cellular functions. The first reports showing a decrease in total rates of protein degradation with age are dated more than 50 years ago, when the major players in protein degradation where still to be discovered. The current advances in the molecular characterization of the two main intracellular proteolytic systems, the lysosomal and the ubiquitin proteasome system, offer now the possibility of a systematic search for the defect(s) that lead to the declined activity of these systems in old organisms. We discuss here, in light of the current findings, how malfunctioning of these two proteolytic systems can contribute to different aspects of the phenotype of aging and to the pathogenesis of some age-related diseases.
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Affiliation(s)
- Marta Martinez-Vicente
- Department of Anatomy and Structural Biology, Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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Attaix D, Mosoni L, Dardevet D, Combaret L, Mirand PP, Grizard J. Altered responses in skeletal muscle protein turnover during aging in anabolic and catabolic periods. Int J Biochem Cell Biol 2005; 37:1962-73. [PMID: 15905114 DOI: 10.1016/j.biocel.2005.04.009] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2004] [Revised: 03/15/2005] [Accepted: 04/12/2005] [Indexed: 12/25/2022]
Abstract
One of the most important effects of aging is sarcopenia, which is associated with impaired locomotion and general weakness. In addition, there is increased susceptibility to illness in aging, which often results in muscle wasting episodes. In such instances, the mobilization of muscle proteins provides free amino acids that are used for energetic purpose, the synthesis of acute phase proteins, and the immune response. However, since muscle protein mass is already depleted, the ability of the aged organism to recover from stress is impaired. Therefore, elucidating the mechanisms that result in sarcopenia is of obvious importance. Age-related changes in protein synthesis and proteolysis are rather small and our current methodology does not enable one to establish unequivocally whether sarcopenia results from depressed protein synthesis, increased proteolysis or both. By contrast, in anabolic and catabolic periods, a number of dysregulations in muscle protein turnover became clearly apparent. The aim of this review is to provide an overview of such altered responses to nutrients and catabolic treatments, which may ultimately contribute to explain sarcopenia. This includes impaired recovery in catabolic states, impaired anabolic effects of nutrients, in particular leucine, and a lack of regulation of the ubiquitin-proteasome proteolytic system. These alterations are discussed with respect to modifications in the insulin/IGF-1 axis and glucocorticoid related effects.
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Affiliation(s)
- Didier Attaix
- Human Nutrition Research Center of Clermont-Ferrand, Institut National de la Recherche Agronomique, Nutrition and Protein Metabolism Unit, 63122 Ceyrat, France.
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