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Xia H, Scholtes C, Dufour CR, Guluzian C, Giguère V. ERRα fosters running endurance by driving myofiber aerobic transformation and fuel efficiency. Mol Metab 2023; 78:101814. [PMID: 37802398 PMCID: PMC10590867 DOI: 10.1016/j.molmet.2023.101814] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 09/20/2023] [Accepted: 09/28/2023] [Indexed: 10/10/2023] Open
Abstract
OBJECTIVE Estrogen related receptor α (ERRα) occupies a central node in the transcriptional control of energy metabolism, including in skeletal muscle, but whether modulation of its activity can directly contribute to extend endurance to exercise remains to be investigated. The goal of this study was to characterize the benefit of mice engineered to express a physiologically relevant activated form of ERRα on skeletal muscle exercise metabolism and performance. METHODS We recently shown that mutational inactivation of three regulated phosphosites in the amino terminal domain of the nuclear receptor ERRα impedes its degradation, leading to an accumulation of ERRα proteins and perturbation of metabolic homeostasis in ERRα3SA mutant mice. Herein, we used a multi-omics approach in combination with physical endurance tests to ascertain the consequences of expressing the constitutively active phospho-deficient ERRα3SA form on muscle exercise performance and energy metabolism. RESULTS Genetic heightening of ERRα activity enhanced exercise capacity, fatigue-resistance, and endurance. This phenotype resulted from extensive reprogramming of ERRα global DNA occupancy and transcriptome in muscle leading to an increase in oxidative fibers, mitochondrial biogenesis, fatty acid oxidation, and lactate homeostasis. CONCLUSION Our findings support the potential to enhance physical performance and exercise-induced health benefits by targeting molecular pathways regulating ERRα transcriptional activity.
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Affiliation(s)
- Hui Xia
- Goodman Cancer Institute, McGill University, Montréal, Québec, Canada H3A 1A3; Department of Biochemistry, Faculty of Medicine and Health Sciences, McGill University, Montréal, Québec, Canada H3G 1Y6
| | - Charlotte Scholtes
- Goodman Cancer Institute, McGill University, Montréal, Québec, Canada H3A 1A3
| | - Catherine R Dufour
- Goodman Cancer Institute, McGill University, Montréal, Québec, Canada H3A 1A3
| | - Christina Guluzian
- Goodman Cancer Institute, McGill University, Montréal, Québec, Canada H3A 1A3; Department of Biochemistry, Faculty of Medicine and Health Sciences, McGill University, Montréal, Québec, Canada H3G 1Y6
| | - Vincent Giguère
- Goodman Cancer Institute, McGill University, Montréal, Québec, Canada H3A 1A3; Department of Biochemistry, Faculty of Medicine and Health Sciences, McGill University, Montréal, Québec, Canada H3G 1Y6.
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Schmitt RE, Dasgupta A, Arneson‐Wissink PC, Datta S, Ducharme AM, Doles JD. Muscle stem cells contribute to long-term tissue repletion following surgical sepsis. J Cachexia Sarcopenia Muscle 2023; 14:1424-1440. [PMID: 36883680 PMCID: PMC10235871 DOI: 10.1002/jcsm.13214] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 01/18/2023] [Accepted: 02/03/2023] [Indexed: 03/09/2023] Open
Abstract
BACKGROUND Over the past decade, advances in sepsis identification and management have resulted in decreased sepsis mortality. This increase in survivorship has highlighted a new clinical obstacle: chronic critical illness (CCI), for which there are no effective treatment options. Up to half of sepsis survivors suffer from CCI, which can include multi-organ dysfunction, chronic inflammation, muscle wasting, physical and mental disabilities, and enhanced frailty. These symptoms prevent survivors from returning to regular day-to-day activities and are directly associated with poor quality of life. METHODS Mice were subjected to cecal ligation and puncture (CLP) with daily chronic stress (DCS) as an in vivo model to study sepsis late-effects/sequelae on skeletal muscle components. Longitudinal monitoring was performed via magnetic resonance imaging, skeletal muscle and/or muscle stem cell (MuSCs) assays (e.g., post-necropsy wet muscle weights, minimum Feret diameter measurements, in vitro MuSC proliferation and differentiation, number of regenerating myofibres and numbers of Pax7-positive nuclei per myofibre), post-sepsis whole muscle metabolomics and MuSC isolation and high-content transcriptional profiling. RESULTS We report several findings supporting the hypothesis that MuSCs/muscle regeneration are critically involved in post-sepsis muscle recovery. First, we show that genetic ablation of muscle stem cells (MuSCs) impairs post-sepsis muscle recovery (maintenance of 5-8% average lean mass loss compared with controls). Second, we observe impaired MuSCs expansion capacity and morphological defects at 26 days post-sepsis compared with control MuSCs (P < 0.001). Third, when subjected to an experimental muscle injury, sepsis-recovered mice exhibited evidence of impaired muscle regeneration compared with non-septic mice receiving the same muscle injury (CLP/DCS injured mean minimum Feret is 92.1% of control injured, P < 0.01). Fourth, we performed a longitudinal RNA sequencing study on MuSCs isolated from post-sepsis mice and found clear transcriptional differences in all post-sepsis samples compared with controls. At Day 28, CLP/DCS mice satellite cells have multiple altered metabolic pathways, such as oxidative phosphorylation, mitochondrial dysfunction, sirtuin signalling and oestrogen receptor signalling, compared with controls (P < 0.001). CONCLUSIONS Our data show that MuSCs and muscle regeneration are required for effective post-sepsis muscle recovery and that sepsis triggers morphological, functional, and transcriptional changes in MuSCs. Moving forward, we strive to leverage a more complete understanding of post-sepsis MuSC/regenerative defects to identify and test novel therapies that promote muscle recovery and improve quality of life in sepsis survivors.
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Affiliation(s)
- Rebecca E. Schmitt
- Department of Biochemistry and Molecular BiologyMayo ClinicRochesterMNUSA
- Department of Anatomy, Cell Biology, and PhysiologyIndiana University School of MedicineIndianapolisINUSA
- Indiana Center for Musculoskeletal HealthIndianapolisINUSA
| | - Aneesha Dasgupta
- Department of Biochemistry and Molecular BiologyMayo ClinicRochesterMNUSA
- Department of Anatomy, Cell Biology, and PhysiologyIndiana University School of MedicineIndianapolisINUSA
- Indiana Center for Musculoskeletal HealthIndianapolisINUSA
| | | | | | | | - Jason D. Doles
- Department of Biochemistry and Molecular BiologyMayo ClinicRochesterMNUSA
- Department of Anatomy, Cell Biology, and PhysiologyIndiana University School of MedicineIndianapolisINUSA
- Indiana Center for Musculoskeletal HealthIndianapolisINUSA
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TGF-β Pathway Inhibition Protects the Diaphragm From Sepsis-Induced Wasting and Weakness in Rat. Shock 2021; 53:772-778. [PMID: 32413000 DOI: 10.1097/shk.0000000000001393] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Sepsis is a frequent complication in patients in intensive care units (ICU). Diaphragm weakness, one of the most common symptoms observed, can lead to weaning problems during mechanical ventilation. Over the last couple of years, members of the transforming growth factor (TGF) β family, such as myostatin, activin A, and TGF-β1, have been reported to strongly trigger the activation of protein breakdown involved in muscle wasting. The aim of this study was to investigate the effect of TGF-β inhibitor LY364947 on the diaphragm during chronic sepsis.Rats were separated into four groups exposed to different experimental conditions: Control group, Septic group, Septic group with inhibitor from day 0 (LY D0), and Septic group with inhibitor from day 1 (LY D1). Sepsis was induced in rats by cecal ligation and puncture, and carried out for 7 days.Chronic sepsis was responsible for a decrease in body weight, food intake and diaphragm's mass. The inhibitor was able to abolish diaphragm wasting only in the LY D1 group. Similarly, LY364947 had a beneficial effect on the diaphragm contraction only for the LY D1 group. SMAD3 was over-expressed and phosphorylated within rats in the Septic group; however, this effect was reversed by LY364947. Calpain-1 and -2 as well as MAFbx were over-expressed within individuals in the Septic group. Yet, calpain-1 and MAFbx expressions were decreased by LY364947.With this work, we demonstrate for the first time that the inhibition of TGF-β pathway during chronic sepsis protects the diaphragm from wasting and weakness as early as one day post infection. This could lead to more efficient treatment and care for septic patients in ICU.
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Kino M, Hayashi T, Hino D, Nakada T, Kitoh H, Akakura K. Patients' poor performance status is an independent risk factor for urosepsis induced by kidney and ureteral stones. Urolithiasis 2021; 49:477-484. [PMID: 33755744 DOI: 10.1007/s00240-021-01256-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Accepted: 02/12/2021] [Indexed: 12/29/2022]
Abstract
This study was aimed to identify the risk factors for urosepsis caused by kidney and ureteral stones. One hundred and nine patients who had kidney or ureteral stones and who were treated with trans-ureteral lithotripsy (TUL) at our institution from 2016 to 2020 were included. We investigated the risk factors for urosepsis caused by kidney or ureteral stones that occurred prior to TUL. Thirty patients (28%) had urosepsis prior to TUL. Patients were divided into a urosepsis group (n = 30, 28%) and a non-urosepsis group (n = 79, 72%). Patients' characteristics (gender, age, performance status [PS] score, presence of diabetes mellitus, and skeletal muscle mass), as well as their stone and urine characteristics (stone size, presence of obstructive ureteral stones, stone composition, and urine and stone cultures), were compared between the two groups. When compared to the non-urosepsis group, patients with urosepsis were more likely to be older (p < 0.001), female (p < 0.001), with lower skeletal muscle mass (p < 0.001) and with poor PSs (p < 0.001). For stone and urine characteristics, infection stones (p = 0.01), positive urine (p < 0.001) and stone culture (p = 0.007) were more often detected in patients with urosepsis. A multivariate analysis showed patients' poor PS to be an independent risk factor for urosepsis due to kidney and ureteral stones (OR = 15.7; 95% CI = 2.2-115, p = 0.007). Our study revealed that the most significant risk factor for urosepsis caused by kidney and ureteral stones was the patients' poor PS.
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Affiliation(s)
- Mika Kino
- Department of Urology, JCHO Tokyo Shinjuku Medical Center, 5-1, Tsukudo - cho, Shinjuku - ku, Tokyo, 162 - 8543, Japan.
| | - Takumi Hayashi
- Department of Urology, JCHO Tokyo Shinjuku Medical Center, 5-1, Tsukudo - cho, Shinjuku - ku, Tokyo, 162 - 8543, Japan
| | - Daichi Hino
- Department of Urology, JCHO Tokyo Shinjuku Medical Center, 5-1, Tsukudo - cho, Shinjuku - ku, Tokyo, 162 - 8543, Japan
| | - Takako Nakada
- Department of Urology, JCHO Tokyo Shinjuku Medical Center, 5-1, Tsukudo - cho, Shinjuku - ku, Tokyo, 162 - 8543, Japan
| | - Hiroki Kitoh
- Department of Urology, JCHO Tokyo Shinjuku Medical Center, 5-1, Tsukudo - cho, Shinjuku - ku, Tokyo, 162 - 8543, Japan
| | - Koichiro Akakura
- Department of Urology, JCHO Tokyo Shinjuku Medical Center, 5-1, Tsukudo - cho, Shinjuku - ku, Tokyo, 162 - 8543, Japan
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Ollewagen T, Myburgh KH, van de Vyver M, Smith C. Rheumatoid cachexia: the underappreciated role of myoblast, macrophage and fibroblast interplay in the skeletal muscle niche. J Biomed Sci 2021; 28:15. [PMID: 33658022 PMCID: PMC7931607 DOI: 10.1186/s12929-021-00714-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Accepted: 02/11/2021] [Indexed: 12/24/2022] Open
Abstract
Although rheumatoid arthritis affects 1% of the global population, the role of rheumatoid cachexia, which occurs in up to a third of patients, is relatively neglected as research focus, despite its significant contribution to decreased quality of life in patients. A better understanding of the cellular and molecular processes involved in rheumatoid cachexia, as well as its potential treatment, is dependent on elucidation of the intricate interactions of the cells involved, such as myoblasts, fibroblasts and macrophages. Persistent RA-associated inflammation results in a relative depletion of the capacity for regeneration and repair in the satellite cell niche. The repair that does proceed is suboptimal due to dysregulated communication from the other cellular role players in this multi-cellular environment. This includes the incomplete switch in macrophage phenotype resulting in a lingering pro-inflammatory state within the tissues, as well as fibroblast-associated dysregulation of the dynamic control of the extracellular matrix. Additional to this endogenous dysregulation, some treatment strategies for RA may exacerbate muscle wasting and no multi-cell investigation has been done in this context. This review summarizes the most recent literature characterising clinical RA cachexia and links these features to the roles of and complex communication between multiple cellular contributors in the muscle niche, highlighting the importance of a targeted approach to therapeutic intervention.
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Affiliation(s)
- T Ollewagen
- Department of Physiological Sciences, Science Faculty, Stellenbosch University, Stellenbosch, South Africa
| | - K H Myburgh
- Department of Physiological Sciences, Science Faculty, Stellenbosch University, Stellenbosch, South Africa
| | - M van de Vyver
- Division of Clinical Pharmacology, Department of Medicine, Faculty of Medicine and Health Sciences, Stellenbosch University, Parow, South Africa
| | - C Smith
- Division of Clinical Pharmacology, Department of Medicine, Faculty of Medicine and Health Sciences, Stellenbosch University, Parow, South Africa.
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Blasco A, Gras S, Mòdol-Caballero G, Tarabal O, Casanovas A, Piedrafita L, Barranco A, Das T, Pereira SL, Navarro X, Rueda R, Esquerda JE, Calderó J. Motoneuron deafferentation and gliosis occur in association with neuromuscular regressive changes during ageing in mice. J Cachexia Sarcopenia Muscle 2020; 11:1628-1660. [PMID: 32691534 PMCID: PMC7749545 DOI: 10.1002/jcsm.12599] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 06/05/2020] [Accepted: 06/15/2020] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND The cellular mechanisms underlying the age-associated loss of muscle mass and function (sarcopenia) are poorly understood, hampering the development of effective treatment strategies. Here, we performed a detailed characterization of age-related pathophysiological changes in the mouse neuromuscular system. METHODS Young, adult, middle-aged, and old (1, 4, 14, and 24-30 months old, respectively) C57BL/6J mice were used. Motor behavioural and electrophysiological tests and histological and immunocytochemical procedures were carried out to simultaneously analyse structural, molecular, and functional age-related changes in distinct cellular components of the neuromuscular system. RESULTS Ageing was not accompanied by a significant loss of spinal motoneurons (MNs), although a proportion (~15%) of them in old mice exhibited an abnormally dark appearance. Dark MNs were also observed in adult (~9%) and young (~4%) animals, suggesting that during ageing, some MNs undergo early deleterious changes, which may not lead to MN death. Old MNs were depleted of cholinergic and glutamatergic inputs (~40% and ~45%, respectively, P < 0.01), suggestive of age-associated alterations in MN excitability. Prominent microgliosis and astrogliosis [~93% (P < 0.001) and ~100% (P < 0.0001) increase vs. adults, respectively] were found in old spinal cords, with increased density of pro-inflammatory M1 microglia and A1 astroglia (25-fold and 4-fold increase, respectively, P < 0.0001). Ageing resulted in significant reductions in the nerve conduction velocity and the compound muscle action potential amplitude (~30%, P < 0.05, vs. adults) in old distal plantar muscles. Compared with adult muscles, old muscles exhibited significantly higher numbers of both denervated and polyinnervated neuromuscular junctions, changes in fibre type composition, higher proportion of fibres showing central nuclei and lipofuscin aggregates, depletion of satellite cells, and augmented expression of different molecules related to development, plasticity, and maintenance of neuromuscular junctions, including calcitonin gene-related peptide, growth associated protein 43, agrin, fibroblast growth factor binding protein 1, and transforming growth factor-β1. Overall, these alterations occurred at varying degrees in all the muscles analysed, with no correlation between the age-related changes observed and myofiber type composition or muscle topography. CONCLUSIONS Our data provide a global view of age-associated neuromuscular changes in a mouse model of ageing and help to advance understanding of contributing pathways leading to development of sarcopenia.
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Affiliation(s)
- Alba Blasco
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Sílvia Gras
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Guillem Mòdol-Caballero
- Grup de Neuroplasticitat i Regeneració, Institut de Neurociències, Departament de Biologia Cel·lular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, CIBERNED, Bellaterra, Spain
| | - Olga Tarabal
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Anna Casanovas
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Lídia Piedrafita
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | | | - Tapas Das
- Abbott Nutrition Research and Development, Columbus, OH, USA
| | | | - Xavier Navarro
- Grup de Neuroplasticitat i Regeneració, Institut de Neurociències, Departament de Biologia Cel·lular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, CIBERNED, Bellaterra, Spain
| | - Ricardo Rueda
- Abbott Nutrition Research and Development, Granada, Spain
| | - Josep E Esquerda
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Jordi Calderó
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
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Wang W, Xu C, Ma X, Zhang X, Xie P. Intensive Care Unit-Acquired Weakness: A Review of Recent Progress With a Look Toward the Future. Front Med (Lausanne) 2020; 7:559789. [PMID: 33330523 PMCID: PMC7719824 DOI: 10.3389/fmed.2020.559789] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 09/11/2020] [Indexed: 12/16/2022] Open
Abstract
Intensive care unit-acquired weakness (ICU-AW), a common neuromuscular complication associated with patients in the ICU, is a type of skeletal muscle dysfunction that commonly occurs following sepsis, mobility restriction, hyperglycemia, and the use of glucocorticoids or neuromuscular blocking agents. ICU-AW can lead to delayed withdrawal of mechanical ventilation and extended hospitalization. Patients often have poor prognosis, limited mobility, and severely affected quality of life. Currently, its pathogenesis is uncertain, with unavailability of specific drugs or targeted therapies. ICU-AW has gained attention in recent years. This manuscript reviews the current research status of the epidemiology, pathogenesis, diagnosis, and treatment methods for ICU-AW and speculates the novel perspectives for future research.
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Affiliation(s)
- Wenkang Wang
- Department of Critical Care Medicine of the Third Affiliated Hospital (The First People's Hospital of Zunyi), Zunyi Medical University, Zunyi, China
| | - Chuanjie Xu
- Department of Critical Care Medicine of the Third Affiliated Hospital (The First People's Hospital of Zunyi), Zunyi Medical University, Zunyi, China
| | - Xinglong Ma
- Department of Critical Care Medicine of the Third Affiliated Hospital (The First People's Hospital of Zunyi), Zunyi Medical University, Zunyi, China
| | - Xiaoming Zhang
- Department of Molecular and Cellular Biology, Baylor College of Medicine Houston, Houston, TX, United States
| | - Peng Xie
- Department of Critical Care Medicine of the Third Affiliated Hospital (The First People's Hospital of Zunyi), Zunyi Medical University, Zunyi, China
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Vohra R, Campbell MD, Park J, Whang S, Gravelle K, Wang YN, Hwang JH, Marcinek DJ, Lee D. Increased tumour burden alters skeletal muscle properties in the KPC mouse model of pancreatic cancer. JCSM RAPID COMMUNICATIONS 2020; 3:44-55. [PMID: 33073264 PMCID: PMC7566781 DOI: 10.1002/rco2.13] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
BACKGROUND Cancer cachexia is a multifactorial wasting syndrome that is characterized by the loss of skeletal muscle mass and weakness, which compromises physical function, reduces quality of life, and ultimately can lead to mortality. Experimental models of cancer cachexia have recapitulated this skeletal muscle atrophy and consequent decline in muscle force generating capacity. We address these issues in a novel transgenic mouse model Kras, Trp53 and Pdx-1-Cre (KPC) of pancreatic ductal adenocarcinoma (PDA) using multi-parametric magnetic resonance (mp-MR) measures. METHODS KPC mice (n = 10) were divided equally into two groups (n = 5/group) depending on the size of the tumor i.e. tumor size <250 mm3 and >250 mm3. Using mp-MR measures, we demonstrated the changes in the gastrocnemius muscle at the microstructural level. In addition, we evaluated skeletal muscle contractile function in KPC mice using an in vivo approach. RESULTS Increase in tumor size resulted in decrease in gastrocnemius maximum cross sectional area, decrease in T2 relaxation time, increase in magnetization transfer ratio, decrease in mean diffusivity, and decrease in radial diffusivity of water across the muscle fibers. Finally, we detected significant decrease in absolute and specific force production of gastrocnemius muscle with increase in tumor size. CONCLUSIONS Our findings indicate that increase in tumor size may cause alterations in structural and functional parameters of skeletal muscles and that MR parameters may be used as sensitive biomarkers to noninvasively detect structural changes in cachectic muscles.
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Affiliation(s)
- Ravneet Vohra
- Department of Radiology, University of Washington, Seattle,
USA
| | | | - Joshua Park
- Department of Radiology, University of Washington, Seattle,
USA
| | - Stella Whang
- Department of Medicine, University of Washington, Seattle,
USA
| | - Kayla Gravelle
- Department of Medicine, University of Washington, Seattle,
USA
| | - Yak-Nam Wang
- Applied Physics Laboratory, University of Washington,
Seattle, USA
| | - Joo-Ha Hwang
- Division of Gastroenterology and Hepatology, Stanford
University, Stanford, USA
| | | | - Donghoon Lee
- Department of Radiology, University of Washington, Seattle,
USA
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Contractility and Myofibrillar Content in Skeletal Muscle are Decreased During Post-Sepsis Recovery, But Not During the Acute Phase of Sepsis. Shock 2020; 55:649-659. [PMID: 32433214 DOI: 10.1097/shk.0000000000001555] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
ABSTRACT Convalescence in humans after severe sepsis occurs over weeks to months and is associated with prolonged functional disabilities and impaired quality-adjusted survival. While much is known regarding the acute early phase of sepsis, there is a knowledge gap pertaining to restoration of muscle mass and function after elimination of the septic nidus. We used a sepsis-recovery model-where cecal-ligation-puncture (CLP) was performed in adult male mice followed 24 h later by removal of the cecum and antibiotic treatment-to assess changes in the abundance of muscle contractile proteins and function during the acute phase of sepsis (24 h post-CLP) and during the recovery phase (day 10 post-CLP). Although body weight and food consumption decreased acutely with sepsis, both had normalized by day 10; however, extensor digitorum longus mass remained decreased 10%. During acute sepsis, there were few contractile defects or significant changes in contractile proteins. In contrast, during sepsis recovery, specific maximum isometric twitch and specific maximum tetanic force were decreased ≈50%, compared with time-matched pair-fed controls, and defects were independent of the concomitant reduction in muscle mass. Force generation in sepsis-recovery mice was decreased 30% with increasing stimulus frequency. Contractile defects during sepsis-recovery were associated with 50% to 90% reductions in thin filament (troponin T, troponin I, tropomyosin, α-sarcomeric actin), thick filament (myosin heavy and myosin light chains), Z-disc (α-actinin 3), and M-band (myomesin-2) proteins, but no change in the intermediate filaments desmin and vimentin. During sepsis recovery, myofibrillar protein synthesis did not differ from control, but synthesis of sarcoplasmic proteins was increased 60%. These data suggest intrinsic defects in muscle contractile function exist during the recovery phase of sepsis and may negatively impact convalescence.
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Yan Z, Spaulding HR. Extracellular superoxide dismutase, a molecular transducer of health benefits of exercise. Redox Biol 2020; 32:101508. [PMID: 32220789 PMCID: PMC7109453 DOI: 10.1016/j.redox.2020.101508] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 03/14/2020] [Accepted: 03/16/2020] [Indexed: 02/06/2023] Open
Abstract
Extracellular superoxide dismutase (EcSOD) is the only extracellular scavenger of superoxide anion (O2.-) with unique binding capacity to cell surface and extracellular matrix through its heparin-binding domain. Enhanced EcSOD activity prevents oxidative stress and damage, which are fundamental in a variety of disease pathologies. In this review we will discuss the findings in humans and animal studies supporting the benefits of EcSOD induced by exercise training in reducing oxidative stress in various tissues. In particularly, we will highlight the importance of skeletal muscle EcSOD, which is induced by endurance exercise and redistributed through the circulation to the peripheral tissues, as a molecular transducer of exercise training to confer protection against oxidative stress and damage in various disease conditions.
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Affiliation(s)
- Zhen Yan
- Center for Skeletal Muscle Research at Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA; Department of Medicine, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA; Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA; Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA.
| | - Hannah R Spaulding
- Center for Skeletal Muscle Research at Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
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Borges RC, Barbeiro HV, Barbeiro DF, Soriano FG. Muscle degradation, vitamin D and systemic inflammation in hospitalized septic patients. J Crit Care 2019; 56:125-131. [PMID: 31896446 DOI: 10.1016/j.jcrc.2019.12.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 12/14/2019] [Accepted: 12/20/2019] [Indexed: 01/05/2023]
Abstract
PURPOSE To date, the relationship between systemic inflammation and muscle changes observed by ultrasonography in septic patients in clinical studies is not known. Furthermore, the role of vitamin D on muscle changes in these patients needs to be investigated. MATERIALS AND METHODS Forty-five patients admitted to the ICU due to severe sepsis or septic shock. Blood samples were collected to evaluate systemic inflammation (interleukin (IL)-10, IL-1β, IL-1α, IL-6, IL-8 and tumor necrosis factor-α(TNF-α)) and vitamin D. Muscle mass was evaluated by ultrasound during hospitalization. Clinical tests of muscle strength (Medical Research Council (MRC) scale and handgrip) were performed after the awakening of patients. RESULTS There was a reduction in day 2 values to hospital discharge on TNF-alpha, IL-8, IL-6 and IL-10 (p < .05). The muscle mass showed a significant decline from day 6 of the ICU. After awakening, the patients had a significant increase in muscle strength (p < .05). There was a positive association between muscle mass variation (day 2 - ICU) with absolute values of IL-8 (r = 0.38 p = .05). For muscle strength, there was a negative association between handgrip strength with IL-8 (r = -0.36 p < .05) on ICU discharge. The vitamin D showed a positive association with the handgrip strength of the day 1 of the awakening (r = 0.51 p < .05). CONCLUSIONS In septic patients, there is an association between inflammation and changes in muscle mass and strength during ICU stay, which is similar to those observed in experimental studies. In addition, there was an association of vitamin D with recovery of muscle strength during hospitalization.
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Affiliation(s)
| | - Hermes Vieira Barbeiro
- Laboratory of Clinical Emergencies - 51, School of Medicine, University of São Paulo, Brazil.
| | | | - Francisco Garcia Soriano
- University Hospital, University of São Paulo, São Paulo, Brazil; Internal Medicine Department, School of Medicine, University of São Paulo, Brazil.
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12
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Talbert EE, Cuitiño MC, Ladner KJ, Rajasekerea PV, Siebert M, Shakya R, Leone GW, Ostrowski MC, Paleo B, Weisleder N, Reiser PJ, Webb A, Timmers CD, Eiferman DS, Evans DC, Dillhoff ME, Schmidt CR, Guttridge DC. Modeling Human Cancer-induced Cachexia. Cell Rep 2019; 28:1612-1622.e4. [PMID: 31390573 PMCID: PMC6733019 DOI: 10.1016/j.celrep.2019.07.016] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 01/24/2019] [Accepted: 07/03/2019] [Indexed: 01/03/2023] Open
Abstract
Cachexia is a wasting syndrome characterized by pronounced skeletal muscle loss. In cancer, cachexia is associated with increased morbidity and mortality and decreased treatment tolerance. Although advances have been made in understanding the mechanisms of cachexia, translating these advances to the clinic has been challenging. One reason for this shortcoming may be the current animal models, which fail to fully recapitulate the etiology of human cancer-induced tissue wasting. Because pancreatic ductal adenocarcinoma (PDA) presents with a high incidence of cachexia, we engineered a mouse model of PDA that we named KPP. KPP mice, similar to PDA patients, progressively lose skeletal and adipose mass as a consequence of their tumors. In addition, KPP muscles exhibit a similar gene ontology as cachectic patients. We envision that the KPP model will be a useful resource for advancing our mechanistic understanding and ability to treat cancer cachexia.
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Affiliation(s)
- Erin E Talbert
- Arthur G. James Comprehensive Cancer Center Cancer Cachexia Program, The Ohio State University, Columbus, OH 43210, USA; Department of Pediatrics, Medical University of South Carolina, Charleston, SC 29425, USA; Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Maria C Cuitiño
- Arthur G. James Comprehensive Cancer Center Cancer Cachexia Program, The Ohio State University, Columbus, OH 43210, USA; Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA; Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Katherine J Ladner
- Arthur G. James Comprehensive Cancer Center Cancer Cachexia Program, The Ohio State University, Columbus, OH 43210, USA
| | - Priyani V Rajasekerea
- Arthur G. James Comprehensive Cancer Center Cancer Cachexia Program, The Ohio State University, Columbus, OH 43210, USA
| | - Melissa Siebert
- Arthur G. James Comprehensive Cancer Center Cancer Cachexia Program, The Ohio State University, Columbus, OH 43210, USA
| | - Reena Shakya
- Arthur G. James Comprehensive Cancer Center Cancer Cachexia Program, The Ohio State University, Columbus, OH 43210, USA
| | - Gustavo W Leone
- Arthur G. James Comprehensive Cancer Center Cancer Cachexia Program, The Ohio State University, Columbus, OH 43210, USA; Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA; Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Michael C Ostrowski
- Arthur G. James Comprehensive Cancer Center Cancer Cachexia Program, The Ohio State University, Columbus, OH 43210, USA; Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA; Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Brian Paleo
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Noah Weisleder
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Peter J Reiser
- Division of Biosciences, The Ohio State University, Columbus, OH 43210, USA
| | - Amy Webb
- Arthur G. James Comprehensive Cancer Center Cancer Cachexia Program, The Ohio State University, Columbus, OH 43210, USA
| | - Cynthia D Timmers
- Arthur G. James Comprehensive Cancer Center Cancer Cachexia Program, The Ohio State University, Columbus, OH 43210, USA; Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA; Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Daniel S Eiferman
- Division of Trauma, Critical Care, and Burn, The Ohio State University, Columbus, OH 43210, USA
| | - David C Evans
- Division of Trauma, Critical Care, and Burn, The Ohio State University, Columbus, OH 43210, USA
| | - Mary E Dillhoff
- Arthur G. James Comprehensive Cancer Center Cancer Cachexia Program, The Ohio State University, Columbus, OH 43210, USA; Division of Surgical Oncology, The Ohio State University, Columbus, OH 43210, USA
| | - Carl R Schmidt
- Arthur G. James Comprehensive Cancer Center Cancer Cachexia Program, The Ohio State University, Columbus, OH 43210, USA; Division of Surgical Oncology, The Ohio State University, Columbus, OH 43210, USA
| | - Denis C Guttridge
- Arthur G. James Comprehensive Cancer Center Cancer Cachexia Program, The Ohio State University, Columbus, OH 43210, USA; Department of Pediatrics, Medical University of South Carolina, Charleston, SC 29425, USA; Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA.
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Redox Status and Muscle Pathology in Rheumatoid Arthritis: Insights from Various Rat Hindlimb Muscles. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:2484678. [PMID: 31049128 PMCID: PMC6458950 DOI: 10.1155/2019/2484678] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 12/21/2018] [Accepted: 01/29/2019] [Indexed: 12/20/2022]
Abstract
Due to atrophy, muscle weakness is a common occurrence in rheumatoid arthritis (RA). The majority of human studies are conducted on the vastus lateralis muscle—a muscle with mixed fiber type—but little comparative data between multiple muscles in either rodent or human models are available. The current study therefore assessed both muscle ultrastructure and selected redox indicators across various muscles in a model of collagen-induced rheumatoid arthritis in female Sprague-Dawley rats. Only three muscles, the gastrocnemius, extensor digitorum longus (EDL), and soleus, had lower muscle mass (38%, 27%, and 25% loss of muscle mass, respectively; all at least P < 0.01), while the vastus lateralis muscle mass was increased by 35% (P < 0.01) in RA animals when compared to non-RA controls. However, all four muscles exhibited signs of deterioration indicative of rheumatoid cachexia. Cross-sectional area was similarly reduced in gastrocnemius, EDL, and soleus (60%, 58%, and 64%, respectively; all P < 0.001), but vastus lateralis (22% smaller, P < 0.05) was less affected, while collagen deposition was significantly increased in muscles. This pathology was associated with significant increases in tissue levels of reactive oxygen species (ROS) in all muscles except the vastus lateralis, while only the gastrocnemius had significantly increased levels of lipid peroxidation (TBARS) and antioxidant activity (FRAP). Current data illustrates the differential responses of different skeletal muscles of the hindlimb to a chronic inflammatory challenge both in terms of redox changes and resistance to cachexia.
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Winje IM, Sheng X, Hansson K, Solbrå A, Tennøe S, Saatcioglu F, Bruusgaard JC, Gundersen K. Cachexia does not induce loss of myonuclei or muscle fibres during xenografted prostate cancer in mice. Acta Physiol (Oxf) 2019; 225:e13204. [PMID: 30325108 DOI: 10.1111/apha.13204] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 10/02/2018] [Accepted: 10/08/2018] [Indexed: 12/25/2022]
Abstract
AIM Cachexia is a severe wasting disorder involving loss of body- and muscle mass reducing survival and quality of life in cancer patients. We aim at determining if cachexia is a mere perturbation of the protein balance or if the condition also involves a degenerative loss of myonuclei within the fibre syncytia or loss of whole muscle fibres. METHODS We induced cachexia by xenografting PC3 prostate cancer cells in nu/nu mice. Six weeks later, we counted myonuclei by in vivo microscopic imaging of single live fibres in the extensor digitorum longus muscle (EDL), and the EDL, soleus and tibialis anterior muscles were also harvested for ex vivo histology. RESULTS The mice lost on average 15% of the whole-body wt. The muscle wet weight of the glycolytic, fast EDL was reduced by 14%, the tibialis anterior by 17%, and the slow, oxidative soleus by 6%. The fibre cross-sectional area in the EDL was reduced by 21% with no loss of myonuclei or any significant reduction in the number of muscle fibres. TUNEL-positive nuclei or fibres with embryonic myosin were rare both in cachectic and control muscles, and haematoxylin-eosin staining revealed no clear signs of muscle pathology. CONCLUSION The data suggest that the cachexia induced by xenografted prostate tumours induces a pronounced atrophy not accompanied by a loss of myonuclei or a loss of muscle fibres. Thus, stem cell related treatment might be redundant, and the quest for treatment options should rather focus on intervening with intracellular pathways regulating muscle fibre size.
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Affiliation(s)
| | - Xia Sheng
- Department of Biosciences University of Oslo Oslo Norway
| | - Kenth‐Arne Hansson
- Department of Biosciences University of Oslo Oslo Norway
- Center for Integrative Neuroplasticity (CINPLA) University of Oslo Oslo Norway
| | - Andreas Solbrå
- Center for Integrative Neuroplasticity (CINPLA) University of Oslo Oslo Norway
- Department of Physics University of Oslo Oslo Norway
| | - Simen Tennøe
- Center for Integrative Neuroplasticity (CINPLA) University of Oslo Oslo Norway
- Department of Informatics University of Oslo Oslo Norway
| | - Fahri Saatcioglu
- Department of Biosciences University of Oslo Oslo Norway
- Institute of Cancer Genetics and Informatics Oslo University Hospital Oslo Norway
| | - Jo Christiansen Bruusgaard
- Department of Biosciences University of Oslo Oslo Norway
- Center for Integrative Neuroplasticity (CINPLA) University of Oslo Oslo Norway
- Department of Health Sciences Kristiania University College Oslo Norway
| | - Kristian Gundersen
- Department of Biosciences University of Oslo Oslo Norway
- Center for Integrative Neuroplasticity (CINPLA) University of Oslo Oslo Norway
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15
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Schwartz LM. Skeletal Muscles Do Not Undergo Apoptosis During Either Atrophy or Programmed Cell Death-Revisiting the Myonuclear Domain Hypothesis. Front Physiol 2019; 9:1887. [PMID: 30740060 PMCID: PMC6356110 DOI: 10.3389/fphys.2018.01887] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 12/12/2018] [Indexed: 12/20/2022] Open
Abstract
Skeletal muscles are the largest cells in the body and are one of the few syncytial ones. There is a longstanding belief that a given nucleus controls a defined volume of cytoplasm, so when a muscle grows (hypertrophy) or shrinks (atrophy), the number of myonuclei change accordingly. This phenomenon is known as the “myonuclear domain hypothesis.” There is a general agreement that hypertrophy is accompanied by the addition of new nuclei from stem cells to help the muscles meet the enhanced synthetic demands of a larger cell. However, there is a considerable controversy regarding the fate of pre-existing nuclei during atrophy. Many researchers have reported that atrophy is accompanied by the dramatic loss of myonuclei via apoptosis. However, since there are many different non-muscle cell populations that reside within the tissue, these experiments cannot easily distinguish true myonuclei from those of neighboring mononuclear cells. Recently, two independent models, one from rodents and the other from insects, have demonstrated that nuclei are not lost from skeletal muscle fibers when they undergo either atrophy or programmed cell death. These and other data argue against the current interpretation of the myonuclear domain hypothesis and suggest that once a nucleus has been acquired by a muscle fiber it persists.
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Affiliation(s)
- Lawrence M Schwartz
- Department of Biology, Morrill Science Center, University of Massachusetts, Amherst, MA, United States
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16
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Boërio D, Corrêa TD, Jakob SM, Ackermann KA, Bostock H, Z'Graggen WJ. Muscle membrane properties in A pig sepsis model: Effect of norepinephrine. Muscle Nerve 2017; 57:808-813. [PMID: 29130505 DOI: 10.1002/mus.26013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2017] [Indexed: 01/15/2023]
Abstract
INTRODUCTION Sepsis-induced myopathy and critical illness myopathy are common causes of muscle weakness in intensive care patients. This study investigated the effect of different mean arterial blood pressure (MAP) levels on muscle membrane properties following experimental sepsis. METHODS Sepsis was induced with fecal peritonitis in 12 of 18 anesthetized and mechanically ventilated pigs. Seven were treated with a high (75-85 mmHg) and 5 were treated with a low (≥60 mmHg) MAP target for resuscitation. In septic animals, resuscitation was started 12 h after peritonitis induction, and muscle velocity recovery cycles were recorded 30 h later. RESULTS Muscles in the sepsis/high MAP group showed an increased relative refractory period and reduced early supernormality compared with the remaining septic animals and the control group, indicating membrane depolarization and/or sodium channel inactivation. The membrane abnormalities correlated positively with norepinephrine dose. DISCUSSION Norepinephrine may contribute to sepsis-induced abnormalities in muscle by impairing microcirculation. Muscle Nerve 57: 808-813, 2018.
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Affiliation(s)
- Delphine Boërio
- Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Thiago D Corrêa
- Intensive Care Unit, Hospital Israelita Albert Einstein, São Paulo, Brazil.,Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Stephan M Jakob
- Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Karin A Ackermann
- Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Hugh Bostock
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom
| | - Werner J Z'Graggen
- Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.,Department of Neurosurgery, Inselspital, Bern University Hospital, University of Bern, 3010, Bern, Switzerland
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17
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Regulation of Akt-mTOR, ubiquitin-proteasome and autophagy-lysosome pathways in locomotor and respiratory muscles during experimental sepsis in mice. Sci Rep 2017; 7:10866. [PMID: 28883493 PMCID: PMC5589872 DOI: 10.1038/s41598-017-11440-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 08/24/2017] [Indexed: 11/17/2022] Open
Abstract
Sepsis induced loss of muscle mass and function contributes to promote physical inactivity and disability in patients. In this experimental study, mice were sacrificed 1, 4, or 7 days after cecal ligation and puncture (CLP) or sham surgery. When compared with diaphragm, locomotor muscles were more prone to sepsis-induced muscle mass loss. This could be attributed to a greater activation of ubiquitin-proteasome system and an increased myostatin expression. Thus, this study strongly suggests that the contractile activity pattern of diaphragm muscle confers resistance to atrophy compared to the locomotor gastrocnemius muscle. These data also suggest that a strategy aimed at preventing the activation of catabolic pathways and preserving spontaneous activity would be of interest for the treatment of patients with sepsis-induced neuromyopathy.
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18
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Leitner LM, Wilson RJ, Yan Z, Gödecke A. Reactive Oxygen Species/Nitric Oxide Mediated Inter-Organ Communication in Skeletal Muscle Wasting Diseases. Antioxid Redox Signal 2017; 26:700-717. [PMID: 27835923 PMCID: PMC5421600 DOI: 10.1089/ars.2016.6942] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
SIGNIFICANCE Cachexia is defined as a complex metabolic syndrome that is associated with underlying illness and a loss of muscle with or without loss of fat mass. This disease is associated with a high incidence with chronic diseases such as heart failure, cancer, chronic obstructive pulmonary disease (COPD), and acquired immunodeficiency syndrome (AIDS), among others. Since there is currently no effective treatment available, cachectic patients have a poor prognosis. Elucidation of the underlying mechanisms is, therefore, an important medical task. Recent Advances: There is accumulating evidence that the diseased organs such as heart, lung, kidney, or cancer tissue secrete soluble factors, including Angiotensin II, myostatin (growth differentiation factor 8 [GDF8]), GDF11, tumor growth factor beta (TGFβ), which act on skeletal muscle. There, they induce a set of genes called atrogenes, which, among others, induce the ubiquitin-proteasome system, leading to protein degradation. Moreover, elevated reactive oxygen species (ROS) levels due to modulation of NADPH oxidases (Nox) and mitochondrial function contribute to disease progression, which is characterized by loss of muscle mass, exercise resistance, and frailty. CRITICAL ISSUES Although substantial progress was achieved to elucidate the pathophysiology of cachexia, effectice therapeutic strategies are urgently needed. FUTURE DIRECTIONS With the identification of key components of the aberrant inter-organ communication leading to cachexia, studies in mice and men to inhibit ROS formation, induction of anti-oxidative superoxide dismutases, and upregulation of muscular nitric oxide (NO) formation either by pharmacological tools or by exercise are promising approaches to reduce the extent of skeletal muscle wasting. Antioxid. Redox Signal. 26, 700-717.
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Affiliation(s)
- Lucia M Leitner
- 1 Institut für Herz- und Kreislaufphysiologie, Heinrich-Heine-Universität Düsseldorf, Universitätsklinikum , Düsseldorf, Germany
| | - Rebecca J Wilson
- 2 Department of Medicine-Cardiovascular Medicine, University of Virginia , Charlottesville, Virginia
| | - Zhen Yan
- 2 Department of Medicine-Cardiovascular Medicine, University of Virginia , Charlottesville, Virginia.,3 Center for Skeletal Muscle Research at Robert Berne Cardiovascular Research Center, University of Virginia , Charlottesville, Virginia
| | - Axel Gödecke
- 1 Institut für Herz- und Kreislaufphysiologie, Heinrich-Heine-Universität Düsseldorf, Universitätsklinikum , Düsseldorf, Germany
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19
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Schwartz LM, Brown C, McLaughlin K, Smith W, Bigelow C. The myonuclear domain is not maintained in skeletal muscle during either atrophy or programmed cell death. Am J Physiol Cell Physiol 2016; 311:C607-C615. [PMID: 27558160 DOI: 10.1152/ajpcell.00176.2016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 08/17/2016] [Indexed: 11/22/2022]
Abstract
Skeletal muscle mass can increase during hypertrophy or decline dramatically in response to normal or pathological signals that trigger atrophy. Many reports have documented that the number of nuclei within these cells is also plastic. It has been proposed that a yet-to-be-defined regulatory mechanism functions to maintain a relatively stable relationship between the cytoplasmic volume and nuclear number within the cell, a phenomenon known as the "myonuclear domain" hypothesis. While it is accepted that hypertrophy is typically associated with the addition of new nuclei to the muscle fiber from stem cells such as satellite cells, the loss of myonuclei during atrophy has been controversial. The intersegmental muscles from the tobacco hawkmoth Manduca sexta are composed of giant syncytial cells that undergo sequential developmental programs of atrophy and programmed cell death at the end of metamorphosis. Since the intersegmental muscles lack satellite cells or regenerative capacity, the tissue is not "contaminated" by these nonmuscle nuclei. Consequently, we monitored muscle mass, cross-sectional area, nuclear number, and cellular DNA content during atrophy and the early phases of cell death. Despite a ∼75-80% decline in muscle mass and cross-sectional area during the period under investigation, there were no reductions in nuclear number or DNA content, and the myonuclear domain was reduced by ∼85%. These data suggest that the myonuclear domain is not an intrinsic property of skeletal muscle and that nuclei persist through atrophy and programmed cell death.
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Affiliation(s)
| | - Christine Brown
- Department of Biology, University of Massachusetts, Amherst, Massachusetts
| | - Kevin McLaughlin
- Department of Biology, University of Massachusetts, Amherst, Massachusetts
| | - Wendy Smith
- Department of Biology, Northeastern University, Boston, Massachusetts; and
| | - Carol Bigelow
- Department of Biostatistics and Epidemiology, University of Massachusetts, Amherst, Massachusetts
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20
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Gómez-SanMiguel AB, Martín AI, Nieto-Bona MP, Fernández-Galaz C, Villanúa MÁ, López-Calderón A. The melanocortin receptor type 3 agonist d-Trp(8)-γMSH decreases inflammation and muscle wasting in arthritic rats. J Cachexia Sarcopenia Muscle 2016; 7:79-89. [PMID: 27066320 PMCID: PMC4799854 DOI: 10.1002/jcsm.12036] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 03/12/2015] [Accepted: 03/30/2015] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Chronic inflammatory diseases induce cachexia that increases mortality and morbidity of the illness. Adjuvant-induced arthritis is an experimental model of rheumatoid arthritis that is associated with body weight loss and muscle wasting. Alpha-melanocyte stimulating hormone has an anti-inflammatory effect in arthritic rats and decreases muscle wasting. The aim of this work was to elucidate whether the anti-cachectic action of alpha-melanocyte stimulating hormone is mediated by the melanocortin receptor type 3 pathway. METHODS Arthritis was induced in male Wistar rats by intradermal injection of Freund's adjuvant, and 6 days afterwards, arthritic rats were injected with the selective melanocortin receptor type 3 agonist d-Trp(8)-gammaMSH ( d-Trp(8)-γMSH) 500 µg/kg subcutaneously. or saline twice a day, for 10 days. RESULTS d-Trp(8)-γMSH decreased the external signs of inflammation and body weight loss, but it was not able to modify the anorexigenic effect of arthritis or the increase in hypothalamic cyclooxygenase-2 (COX-2) expression. In contrast, d-Trp(8)-γMSH prevented arthritis-induced increase in hypothalamic IL-1β and serum corticosterone levels and the decrease in serum IGF-I levels. d-Trp(8)-γMSH treatment also prevented arthritis-induced NF-kB(p65) phosphorylation and tumour necrosis factor-α mRNA increase in the gastrocnemius. d-Trp(8)-γMSH administration to arthritic rats increased gastrocnemius mass, its cross-sectional area, and mean fast fibre area. Those effects of d-Trp(8)-γMSH were associated with a decreased expression of atrogin-1 and muscle ring-finger protein-1 in the gastrocnemius. In rats treated with saline, arthritis increased the expression of autophagy marker genes LC3b, Bnip-3, and Gabarap1 as well as the conversion of LC3b I to LC3b II by lipidation in the gastrocnemius. d-Trp(8)-γMSH decreased gastrocnemius LC3b, Bnip-3, and Gabarap1 mRNA expression and prevented the increase in LC3b II in arthritic rats. CONCLUSION These data suggest that d-Trp(8)-γMSH administration prevents the effect of arthritis on corticosterone and insulin-like growth factor-I serum levels and decreases muscle wasting, by down-regulating atrogenes and autophagy through modifying the NF-kB(p65)/tumour necrosis factor-α signalling transduction pathway.
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Affiliation(s)
| | - Ana Isabel Martín
- Department of Physiology, Faculty of Medicine Complutense University Madrid Spain
| | - María Paz Nieto-Bona
- Department of Basic Sciences in Health, Faculty of Health Sciences Rey Juan Carlos University Madrid Spain
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Cerveró C, Montull N, Tarabal O, Piedrafita L, Esquerda JE, Calderó J. Chronic Treatment with the AMPK Agonist AICAR Prevents Skeletal Muscle Pathology but Fails to Improve Clinical Outcome in a Mouse Model of Severe Spinal Muscular Atrophy. Neurotherapeutics 2016; 13:198-216. [PMID: 26582176 PMCID: PMC4720671 DOI: 10.1007/s13311-015-0399-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a genetic neuromuscular disorder characterized by spinal and brainstem motor neuron (MN) loss and skeletal muscle paralysis. Currently, there is no effective treatment other than supportive care to ameliorate the quality of life of patients with SMA. Some studies have reported that physical exercise, by improving muscle strength and motor function, is potentially beneficial in SMA. The adenosine monophosphate-activated protein kinase agonist 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR) has been reported to be an exercise mimetic agent that is able to regulate muscle metabolism and increase endurance both at rest and during exercise. Chronic AICAR administration has been shown to ameliorate the dystrophic muscle phenotype and motor behavior in the mdx mouse, a model of Duchenne muscular dystrophy. Here, we investigated whether chronic AICAR treatment was able to elicit beneficial effects on motor abilities and neuromuscular histopathology in a mouse model of severe SMA (the SMNΔ7 mouse). We report that AICAR improved skeletal muscle atrophy and structural changes found in neuromuscular junctions of SMNΔ7 animals. However, although AICAR prevented the loss of glutamatergic excitatory synapses on MNs, this compound was not able to mitigate MN loss or the microglial and astroglial reaction occurring in the spinal cord of diseased mice. Moreover, no improvement in survival or motor performance was seen in SMNΔ7 animals treated with AICAR. The beneficial effects of AICAR in SMA found in our study are SMN-independent, as no changes in the expression of this protein were seen in the spinal cord and skeletal muscle of diseased animals treated with this compound.
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Affiliation(s)
- Clàudia Cerveró
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Av. Rovira Roure 80, 25198, Lleida, Catalonia, Spain
| | - Neus Montull
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Av. Rovira Roure 80, 25198, Lleida, Catalonia, Spain
| | - Olga Tarabal
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Av. Rovira Roure 80, 25198, Lleida, Catalonia, Spain
| | - Lídia Piedrafita
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Av. Rovira Roure 80, 25198, Lleida, Catalonia, Spain
| | - Josep E Esquerda
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Av. Rovira Roure 80, 25198, Lleida, Catalonia, Spain
| | - Jordi Calderó
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Av. Rovira Roure 80, 25198, Lleida, Catalonia, Spain.
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22
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Wens I, Dalgas U, Verboven K, Kosten L, Stevens A, Hens N, Eijnde BO. Impact of high intensity exercise on muscle morphology in EAE rats. Physiol Res 2015; 64:907-23. [PMID: 26047382 DOI: 10.33549/physiolres.932824] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The impact of high-intensity exercise on disease progression and muscle contractile properties in experimental autoimmune encephalomyelitis (EAE) remains unclear. Control (CON) and EAE rats were divided into sedentary and exercise groups. Before onset (experiment 1, n=40) and after hindquarter paralysis (experiment 2, n=40), isokinetic foot extensor strength, cross sectional area (CSA) of tibialis anterior (TA), extensor digitorum longus (EDL) and soleus (SOL) and brain-derived neurotrophic factor (BDNF) levels were assessed. EAE reduced muscle fiber CSA of TA, EDL and SOL. In general, exercise was not able to affect CSA, whereas it delayed hindquarter paralysis peak. CON muscle work peaked and declined, while it remained stable in EAE. BDNF-responses were not affected by EAE or exercise. In conclusion, EAE affected CSA-properties of TA, EDL and SOL, which could, partly, explain the absence of peak work during isokinetic muscle performance in EAE-animals. However, exercise was not able to prevent muscle fiber atrophy.
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Affiliation(s)
- I Wens
- REVAL Rehabilitation Research Center, BIOMED Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Diepenbeek, Belgium.
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Aerobic exercise training prevents heart failure-induced skeletal muscle atrophy by anti-catabolic, but not anabolic actions. PLoS One 2014; 9:e110020. [PMID: 25330387 PMCID: PMC4201522 DOI: 10.1371/journal.pone.0110020] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 09/14/2014] [Indexed: 01/05/2023] Open
Abstract
Background Heart failure (HF) is associated with cachexia and consequent exercise intolerance. Given the beneficial effects of aerobic exercise training (ET) in HF, the aim of this study was to determine if the ET performed during the transition from cardiac dysfunction to HF would alter the expression of anabolic and catabolic factors, thus preventing skeletal muscle wasting. Methods and Results We employed ascending aortic stenosis (AS) inducing HF in Wistar male rats. Controls were sham-operated animals. At 18 weeks after surgery, rats with cardiac dysfunction were randomized to 10 weeks of aerobic ET (AS-ET) or to an untrained group (AS-UN). At 28 weeks, the AS-UN group presented HF signs in conjunction with high TNF-α serum levels; soleus and plantaris muscle atrophy; and an increase in the expression of TNF-α, NFκB (p65), MAFbx, MuRF1, FoxO1, and myostatin catabolic factors. However, in the AS-ET group, the deterioration of cardiac function was prevented, as well as muscle wasting, and the atrophy promoters were decreased. Interestingly, changes in anabolic factor expression (IGF-I, AKT, and mTOR) were not observed. Nevertheless, in the plantaris muscle, ET maintained high PGC1α levels. Conclusions Thus, the ET capability to attenuate cardiac function during the transition from cardiac dysfunction to HF was accompanied by a prevention of skeletal muscle atrophy that did not occur via an increase in anabolic factors, but through anti-catabolic activity, presumably caused by PGC1α action. These findings indicate the therapeutic potential of aerobic ET to block HF-induced muscle atrophy by counteracting the increased catabolic state.
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Ackermann KA, Bostock H, Brander L, Schröder R, Djafarzadeh S, Tuchscherer D, Jakob SM, Takala J, Z'Graggen WJ. Early changes of muscle membrane properties in porcine faecal peritonitis. Crit Care 2014; 18:484. [PMID: 25145497 PMCID: PMC4159512 DOI: 10.1186/s13054-014-0484-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 07/29/2014] [Indexed: 12/02/2022] Open
Abstract
Introduction Sepsis-induced myopathy and critical illness myopathy (CIM) are possible causes of muscle weakness in intensive care patients. They have been attributed to muscle membrane dysfunction. The aim of this study was to investigate membrane properties in the early stage of experimental sepsis by evaluating muscle excitability. Methods In total, 20 anaesthetized and mechanically ventilated pigs were randomized to either faecal peritonitis (n = 10) or to non-septic controls (n = 10). Resuscitation with fluids and vasoactive drugs was started 3 hours after peritonitis induction. Muscle membrane properties were investigated by measuring muscle velocity recovery cycles before induction of peritonitis as well as 6, 18 and 27 hours thereafter. Muscle relative refractory period (MRRP) and early supernormality (ESN) were assessed. Results Peritonitis lasting 27 hours was associated with an increase of MRRP by 28% from 2.38 ± 0.18 ms (mean ± SD) to 3.47 ± 1.79 ms (P <0.01) and a decrease of ESN by 31% from 9.64 ± 2.82% to 6.50 ± 2.64% (P <0.01). ESN reduction was already apparent 6 hours after induction of peritonitis. Values in controls did not show any significant alterations. Conclusions Muscle membrane abnormalities consistent with membrane depolarization and/or sodium channel inactivation occurred within 6 hours of peritonitis induction. This indicates that changes that have been described in established sepsis-induced myopathy and/or CIM start early in the course of sepsis. Muscle excitability testing facilitates evaluation of the time course of these changes. Electronic supplementary material The online version of this article (doi:10.1186/s13054-014-0484-2) contains supplementary material, which is available to authorized users.
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Gueret G, Guillouet M, Vermeersch V, Guillard E, Talarmin H, Nguyen BV, Rannou F, Giroux-Metges MA, Pennec JP, Ozier Y. [ICU acquired neuromyopathy]. ACTA ACUST UNITED AC 2013; 32:580-91. [PMID: 23958176 DOI: 10.1016/j.annfar.2013.05.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2012] [Accepted: 05/08/2013] [Indexed: 12/19/2022]
Abstract
ICU acquired neuromyopathy (IANM) is the most frequent neurological pathology observed in ICU. Nerve and muscle defects are merged with neuromuscular junction abnormalities. Its physiopathology is complex. The aim is probably the redistribution of nutriments and metabolism towards defense against sepsis. The main risk factors are sepsis, its severity and its duration of evolution. IANM is usually diagnosed in view of difficulties in weaning from mechanical ventilation, but electrophysiology may allow an earlier diagnosis. There is no curative therapy, but early treatment of sepsis, glycemic control as well as early physiotherapy may decrease its incidence. The outcomes of IANM are an increase in morbi-mortality and possibly long-lasting neuromuscular abnormalities as far as tetraplegia.
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Affiliation(s)
- G Gueret
- Pôle anesthésie réanimations soins intensifs blocs opératoires urgences (ARSIBOU), CHRU de Brest, boulevard Tanguy-Prigent, 29200 Brest, France; Laboratoire de physiologie, faculté de médecine et des sciences de la santé, EA 1274 (mouvement, sport santé), université de Bretagne-Occidentale, 22, avenue Camille-Desmoulins, 29200 Brest, France; Université européenne de Bretagne, 5, boulevard Laennec, 35000 Rennes, France.
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Roberts BM, Frye GS, Ahn B, Ferreira LF, Judge AR. Cancer cachexia decreases specific force and accelerates fatigue in limb muscle. Biochem Biophys Res Commun 2013; 435:488-92. [PMID: 23673294 DOI: 10.1016/j.bbrc.2013.05.018] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 05/03/2013] [Indexed: 11/26/2022]
Abstract
Cancer cachexia is a complex metabolic syndrome that is characterized by the loss of skeletal muscle mass and weakness, which compromises physical function, reduces quality of life, and ultimately can lead to mortality. Experimental models of cancer cachexia have recapitulated this skeletal muscle atrophy and consequent decline in muscle force generating capacity. However, more recently, we provided evidence that during severe cancer cachexia muscle weakness in the diaphragm muscle cannot be entirely accounted for by the muscle atrophy. This indicates that muscle weakness is not just a consequence of muscle atrophy but that there is also significant contractile dysfunction. The current study aimed to determine whether contractile dysfunction is also present in limb muscles during severe Colon-26 (C26) carcinoma cachexia by studying the glycolytic extensor digitorum longus (EDL) muscle and the oxidative soleus muscle, which has an activity pattern that more closely resembles the diaphragm. Severe C-26 cancer cachexia caused significant muscle fiber atrophy and a reduction in maximum absolute force in both the EDL and soleus muscles. However, normalization to muscle cross sectional area further demonstrated a 13% decrease in maximum isometric specific force in the EDL and an even greater decrease (17%) in maximum isometric specific force in the soleus. Time to peak tension and half relaxation time were also significantly slowed in both the EDL and the solei from C-26 mice compared to controls. Since, in addition to postural control, the oxidative soleus is also important for normal locomotion, we further performed a fatigue trial in the soleus and found that the decrease in relative force was greater and more rapid in solei from C-26 mice compared to controls. These data demonstrate that severe cancer cachexia causes profound muscle weakness that is not entirely explained by the muscle atrophy. In addition, cancer cachexia decreases the fatigue resistance of the soleus muscle, a postural muscle typically resistant to fatigue. Thus, specifically targeting contractile dysfunction represents an additional means to counter muscle weakness in cancer cachexia, in addition to targeting the prevention of muscle atrophy.
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Affiliation(s)
- B M Roberts
- 1225 Center Drive, HPNP Building Room 1142, Department of Physical Therapy, University of Florida, Gainesville, FL 32610, USA
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27
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Xu R, Andres-Mateos E, Mejias R, MacDonald EM, Leinwand LA, Merriman DK, Fink RHA, Cohn RD. Hibernating squirrel muscle activates the endurance exercise pathway despite prolonged immobilization. Exp Neurol 2013; 247:392-401. [PMID: 23333568 DOI: 10.1016/j.expneurol.2013.01.005] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 01/02/2013] [Accepted: 01/09/2013] [Indexed: 10/27/2022]
Abstract
Skeletal muscle atrophy is a very common clinical challenge in many disuse conditions. Maintenance of muscle mass is crucial to combat debilitating functional consequences evoked from these clinical conditions. In contrast, hibernation represents a physiological state in which there is natural protection against disuse atrophy despite prolonged periods of immobilization and lack of nutrient intake. Even though peroxisome proliferator-activated receptor γ (PPARγ) coactivator 1-α (PGC-1α) is a central mediator in muscle remodeling pathways, its role in the preservation of skeletal muscle mass during hibernation remains unclear. Since PGC-1α regulates muscle fiber type formation and mitochondrial biogenesis, we analyzed muscles of 13-lined ground squirrels. We find that animals in torpor exhibit a shift to slow-twitch Type I muscle fibers. This switch is accompanied by activation of the PGC-1α-mediated endurance exercise pathway. In addition, we observe increased antioxidant capacity without evidence of oxidative stress, a marked decline in apoptotic susceptibility, and enhanced mitochondrial abundance and metabolism. These results show that activation of the endurance exercise pathway can be achieved in vivo despite prolonged periods of immobilization, and therefore might be an important mechanism for skeletal muscle preservation during hibernation. This PGC-1α regulated pathway may be a potential therapeutic target promoting skeletal muscle homeostasis and oxidative balance to prevent muscle loss in a variety of inherited and acquired neuromuscular disease conditions.
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Affiliation(s)
- Ran Xu
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Kim HC, Cho HY, Hah YS. Role of IL-15 in Sepsis-Induced Skeletal Muscle Atrophy and Proteolysis. Tuberc Respir Dis (Seoul) 2012; 73:312-9. [PMID: 23319993 PMCID: PMC3538184 DOI: 10.4046/trd.2012.73.6.312] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Revised: 10/04/2012] [Accepted: 12/10/2012] [Indexed: 12/23/2022] Open
Abstract
Background Muscle wasting in sepsis is associated with increased proteolysis. Interleukin-15 (IL-15) has been characterized as an anabolic factor for skeletal muscles. Our study aims to investigate the role of IL-15 in sepsis-induced muscle atrophy and proteolysis. Methods Mice were rendered septic either by cecal ligation and puncture or by intraperitoneal injection of lipopolysaccharide (LPS, 10 mg/kg i.p.). Expression of IL-15 mRNA and protein was determined by reverse transcriptase polymerase chain reaction and Western blot analysis in the control and septic limb muscles. C2C12 skeletal muscle cells were stimulated in vitro with either LPS or dexamethasone in the presence and absence of IL-15 and sampled at different time intervals (24, 48, or 72 hours). IL-15 (10µg/kg) was intraperitoneally administered 6 hours before sepsis induction and limb muscles were sampled after 24 hours of sepsis. Cathepsin L activity was determined to measure muscle proteolysis. Atrogin-1 and muscle-specific ring finger protein 1 (MuRF1) expressions in limb muscle protein lysates was analyzed. Results IL-15 mRNA expression was significantly lower in the limb muscles of septic mice compared to that of controls. Cathepsin L activity in C2C12 cells was significantly lower in presence of IL-15, when compared to that observed with individual treatments of LPS or dexamethasone or tumor necrosis factor α. Further, the limb muscles of mice pre-treated with IL-15 prior to sepsis induction showed a lower expression of atrogin-1 and MuRF1 than those not pre-treated. Conclusion IL-15 may play a role in protection against sepsis-induced muscle wasting; thereby, serving as a potential therapeutic target for sepsis-induced skeletal muscle wasting and proteolysis.
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Affiliation(s)
- Ho Cheol Kim
- Department of Internal Medicine, Institute of Health Science, Gyeongsang National University School of Medicine, Jinju, Korea
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Alamdari N, Toraldo G, Aversa Z, Smith I, Castillero E, Renaud G, Qaisar R, Larsson L, Jasuja R, Hasselgren PO. Loss of muscle strength during sepsis is in part regulated by glucocorticoids and is associated with reduced muscle fiber stiffness. Am J Physiol Regul Integr Comp Physiol 2012; 303:R1090-9. [PMID: 23019215 DOI: 10.1152/ajpregu.00636.2011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Sepsis is associated with impaired muscle function but the role of glucocorticoids in sepsis-induced muscle weakness is not known. We tested the role of glucocorticoids in sepsis-induced muscle weakness by treating septic rats with the glucocorticoid receptor antagonist RU38486. In addition, normal rats were treated with dexamethasone to further examine the role of glucocorticoids in the regulation of muscle strength. Sepsis was induced in rats by cecal ligation and puncture, and muscle force generation (peak twitch and tetanic tension) was determined in lower extremity muscles. In other experiments, absolute and specific force as well as stiffness (reflecting the function of actomyosin cross bridges) were determined in isolated skinned muscle fibers from control and septic rats. Sepsis and treatment with dexamethasone resulted in reduced maximal twitch and tetanic force in intact isolated extensor digitorum longus muscles. The absolute and specific maximal force in isolated muscle fibers was reduced during sepsis together with decreased fiber stiffness. These effects of sepsis were blunted (but not abolished) by RU38486. The results suggest that muscle weakness during sepsis is at least in part regulated by glucocorticoids and reflects loss of contractility at the cellular (individual muscle fiber) level. In addition, the results suggest that reduced function of the cross bridges between actin and myosin (documented as reduced muscle fiber stiffness) may be involved in sepsis-induced muscle weakness. An increased understanding of mechanisms involved in loss of muscle strength will be important for the development of new treatment strategies in patients with this debilitating consequence of sepsis.
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Affiliation(s)
- Nima Alamdari
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
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Reed SA, Sandesara PB, Senf SM, Judge AR. Inhibition of FoxO transcriptional activity prevents muscle fiber atrophy during cachexia and induces hypertrophy. FASEB J 2011; 26:987-1000. [PMID: 22102632 DOI: 10.1096/fj.11-189977] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Cachexia is characterized by inexorable muscle wasting that significantly affects patient prognosis and increases mortality. Therefore, understanding the molecular basis of this muscle wasting is of significant importance. Recent work showed that components of the forkhead box O (FoxO) pathway are increased in skeletal muscle during cachexia. In the current study, we tested the physiological significance of FoxO activation in the progression of muscle atrophy associated with cachexia. FoxO-DNA binding dependent transcription was blocked in the muscles of mice through injection of a dominant negative (DN) FoxO expression plasmid prior to inoculation with Lewis lung carcinoma cells or the induction of sepsis. Expression of DN FoxO inhibited the increased mRNA levels of atrogin-1, MuRF1, cathepsin L, and/or Bnip3 and inhibited muscle fiber atrophy during cancer cachexia and sepsis. Interestingly, during control conditions, expression of DN FoxO decreased myostatin expression, increased MyoD expression and satellite cell proliferation, and induced fiber hypertrophy, which required de novo protein synthesis. Collectively, these data show that FoxO-DNA binding-dependent transcription is necessary for normal muscle fiber atrophy during cancer cachexia and sepsis, and further suggest that basal levels of FoxO play an important role during normal conditions to depress satellite cell activation and limit muscle growth.
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Affiliation(s)
- Sarah A Reed
- Department of Physical Therapy, 101 S. Newell Dr., University of Florida, Gainesville, FL 32611, USA
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Wüst RCI, Myers DS, Stones R, Benoist D, Robinson PA, Boyle JP, Peers C, White E, Rossiter HB. Regional skeletal muscle remodeling and mitochondrial dysfunction in right ventricular heart failure. Am J Physiol Heart Circ Physiol 2011; 302:H402-11. [PMID: 22037189 DOI: 10.1152/ajpheart.00653.2011] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Exercise intolerance is a cardinal symptom of right ventricular heart failure (RV HF) and skeletal muscle adaptations play a role in this limitation. We determined regional remodeling of muscle structure and mitochondrial function in a rat model of RV HF induced by monocrotaline injection (MCT; 60 mg·kg(-1); n = 11). Serial sections of the plantaris were stained for fiber type, succinate dehydrogenase (SDH) activity and capillaries. Mitochondrial function was assessed in permeabilized fibers using respirometry, and isolated complex activity by blue native gel electrophoresis (BN PAGE). All measurements were compared with saline-injected control animals (CON; n = 12). Overall fiber cross-sectional area was smaller in MCT than CON: 1,843 ± 114 vs. 2,322 ± 120 μm(2) (P = 0.009). Capillary-to-fiber ratio was lower in MCT in the oxidative plantaris region (1.65 ± 0.09 vs. 1.93 ± 0.07; P = 0.03), but not in the glycolytic region. SDH activity (P = 0.048) and maximal respiratory rate (P = 0.012) were each ∼15% lower in all fibers in MCT. ADP sensitivity was reduced in both skeletal muscle regions in MCT (P = 0.032), but normalized by rotenone. A 20% lower complex I/IV activity in MCT was confirmed by BN PAGE. MCT-treatment was associated with lower mitochondrial volume density (lower SDH activity), quality (lower complex I activity), and fewer capillaries per fiber area in oxidative skeletal muscle. These features are consistent with structural and functional remodeling of the determinants of oxygen supply potential and utilization that may contribute to exercise intolerance and reduced quality of life in patients with RV HF.
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Affiliation(s)
- Rob C I Wüst
- Institute of Membrane and Systems Biology, University of Leeds, Leeds, United Kingdom
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32
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Frost RA, Lang CH. mTor signaling in skeletal muscle during sepsis and inflammation: where does it all go wrong? Physiology (Bethesda) 2011; 26:83-96. [PMID: 21487027 DOI: 10.1152/physiol.00044.2010] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The mammalian target of rapamycin (mTOR) is an evolutionarily conserved protein kinase that exquisitely regulates protein metabolism in skeletal muscle. mTOR integrates input from amino acids, growth factors, and intracellular cues to make or break muscle protein. mTOR accomplishes this task by stimulating the phosphorylation of substrates that control protein translation while simultaneously inhibiting proteasomal and autophagic protein degradation. In a metabolic twist of fate, sepsis induces muscle atrophy in part by the aberrant regulation of mTOR. In this review, we track the steps of normal mTOR signaling in muscle and examine where they go astray in sepsis and inflammation.
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Affiliation(s)
- Robert A Frost
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA
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Geng T, Li P, Yin X, Yan Z. PGC-1α promotes nitric oxide antioxidant defenses and inhibits FOXO signaling against cardiac cachexia in mice. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 178:1738-48. [PMID: 21435455 DOI: 10.1016/j.ajpath.2011.01.005] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Revised: 12/03/2010] [Accepted: 01/04/2011] [Indexed: 12/21/2022]
Abstract
Chronic heart failure often results in catabolic muscle wasting, exercise intolerance, and death. Oxidative muscles, which have greater expression of the metabolic master gene peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) and its target genes, are more resistant to catabolic wasting than are glycolytic muscles; however, the underlying mechanism is unknown. To determine the functional role of PGC-1α in oxidative phenotype-associated protection, skeletal muscle-specific PGC-1α transgenic mice were crossbred with cardiac-specific calsequestrin transgenic mice, a genetic model of chronic heart failure. PGC-1α overexpression in glycolytic muscles significantly attenuated catabolic muscle wasting induced by chronic heart failure. In addition to inactivation of forkhead transcription factor signaling through enhanced Akt/protein kinase B expression, in glycolytic muscles, PGC-1α overexpression led to enhanced expression of inducible nitric oxide synthase and endothelial nitric oxide synthase, production of nitric oxide, and expression of antioxidant enzyme including superoxide dismutases (SOD1, SOD2, and SOD3) and catalase, and reduced oxidative stress. These findings suggest that PGC-1α protects muscle from catabolic wasting in chronic heart failure through enhanced nitric oxide antioxidant defenses and inhibition of the forkhead transcription factor signaling pathways.
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Affiliation(s)
- Tuoyu Geng
- Department of Medicine-Cardiovascular Medicine, University of Virginia, Charlottesville, VA 22908, USA
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LeBrasseur NK, Walsh K, Arany Z. Metabolic benefits of resistance training and fast glycolytic skeletal muscle. Am J Physiol Endocrinol Metab 2011; 300:E3-10. [PMID: 21045171 PMCID: PMC3023213 DOI: 10.1152/ajpendo.00512.2010] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Accepted: 10/30/2010] [Indexed: 12/18/2022]
Abstract
Skeletal muscle exhibits remarkable plasticity with respect to its metabolic properties. Recent work has shown that interventions such as resistance training, genetic alterations and pharmacological strategies that increase muscle mass and glycolytic capacity, and not necessarily oxidative competence, can improve body composition and systemic metabolism. We review here recent advances in our understanding of the signaling and transcriptional regulatory pathways of this strategy and review new evidence obtained from mice and humans that supports the notion that increasing muscle mass and glycolytic capacity may effectively counter insulin resistance and type 2 diabetes mellitus.
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Affiliation(s)
- Nathan K LeBrasseur
- Robert and Arlene Kogod Center on Aging, Department of Physical Medicine and Rehabilitation, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, USA.
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Frost RA, Pereyra E, Lang CH. Ethyl pyruvate preserves IGF-I sensitivity toward mTOR substrates and protein synthesis in C2C12 myotubes. Endocrinology 2011; 152:151-63. [PMID: 21106878 PMCID: PMC3219047 DOI: 10.1210/en.2010-0248] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Bacterial infection decreases skeletal muscle protein synthesis via inhibition of the mammalian target of rapamycin (mTOR), a key regulator of translation initiation. To better define the mechanism by which muscle mTOR activity is decreased, we used an in vitro model of C2C12 myotubes treated with endotoxin [lipopolysaccharide (LPS)]and interferon (IFN)-γ to determine whether stable lipophilic pyruvate derivatives restore mTOR signaling. Myotubes treated with a combination of LPS and IFNγ down-regulated the phosphorylation of the mTOR substrates S6 kinase-1 and 4E binding protein-1. The phosphorylation of ribosomal protein S6 was decreased, whereas phosphorylation of elongation factor-2 was enhanced; all results consistent with defects in both translation initiation and elongation. LPS/IFNγ decreased protein synthesis 60% in myotubes. Treatment with methyl or ethyl pyruvate partially protected against the LPS/IFNγ-induced fall in mTOR signaling. The protective effect of ethyl and methyl pyruvate could not be replicated by an equimolar amount of sodium pyruvate. Although LPS/IFNγ treated myotubes were initially IGF-I responsive, prolonged exposure (≥ 17 h) resulted in IGF-I resistance at the level of mTOR despite normal IGF-I receptor phosphorylation. Ethyl pyruvate treatment restored IGF-I sensitivity as evidenced by the left shift in the IGF-I dose-response curve and maintained IGF-I responsiveness for a prolonged period of time. Ethyl pyruvate also restored IGF-I-stimulated protein synthesis in LPS/IFNγ-treated myotubes. Cotreatment with N-acetyl cysteine or ascorbic acid also preserved IGF-I sensitivity and mTOR activity. The data suggest that the combination of LPS and IFNγ inhibits mTOR activity and that prolonged exposure induces IGF-I resistance in myotubes. Lipophilic pyruvate derivatives and antioxidants show promise at rescuing mTOR activity and muscle protein synthesis by maintaining IGF-I sensitivity in this model.
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Affiliation(s)
- Robert A Frost
- Department of Cellular and Molecular Physiology (H166), Pennsylvania State University College of Medicine, 500 University Drive, Hershey, Pennsylvania 17033, USA.
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van den Berg SAA, Nabben M, Bijland S, Voshol PJ, van Klinken JB, Havekes LM, Romijn JA, Hoeks J, Hesselink MK, Schrauwen P, van Dijk KW. High levels of whole-body energy expenditure are associated with a lower coupling of skeletal muscle mitochondria in C57Bl/6 mice. Metabolism 2010; 59:1612-8. [PMID: 20494374 DOI: 10.1016/j.metabol.2010.03.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Revised: 03/12/2010] [Accepted: 03/15/2010] [Indexed: 12/25/2022]
Abstract
Considerable variation in energy expenditure is observed in C57Bl/6 mice on a high-fat diet. Because muscle tissue is a major determinant of whole-body energy expenditure, we set out to determine the variation in energy expenditure and its possible association with skeletal muscle mitochondrial function upon high-fat diet intervention. Metabolic cages using indirect calorimetry were used to assess whole-body energy metabolism in C57Bl/6 male mice during the first 3 days of high-fat diet intervention. Mice were grouped in a negative or positive residual nocturnal energy expenditure group after correction of total nocturnal energy expenditure for body mass by residual analysis. The positive residual energy expenditure group was characterized by higher uncorrected total nocturnal energy expenditure and food intake. On day 7, mitochondria were isolated from the skeletal muscle of the hind limb. Mitochondrial density was determined by mitochondrial protein content and did not differ between the positive and negative residual energy expenditure groups. Using high-resolution respirometry, mitochondrial oxidative function was assessed using various substrates. Mitochondria from the positive residual energy expenditure group were characterized by a lower adenosine diphosphate-stimulated respiration and lower respiratory control rates using palmitoyl-coenzyme A as substrate. These results indicate that reduced mitochondrial coupling is associated with positive residual energy expenditure and high rates of total energy expenditure in vivo.
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Affiliation(s)
- Sjoerd A A van den Berg
- Department of Human Genetics, Leiden University Medical Center, Leiden 2333 ZC, The Netherlands.
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Menconi MJ, Arany ZP, Alamdari N, Aversa Z, Gonnella P, O'Neal P, Smith IJ, Tizio S, Hasselgren PO. Sepsis and glucocorticoids downregulate the expression of the nuclear cofactor PGC-1beta in skeletal muscle. Am J Physiol Endocrinol Metab 2010; 299:E533-43. [PMID: 20647557 PMCID: PMC2957862 DOI: 10.1152/ajpendo.00596.2009] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Muscle wasting during sepsis is at least in part regulated by glucocorticoids and is associated with increased transcription of genes encoding the ubiquitin ligases atrogin-1 and muscle-specific RING-finger protein-1 (MuRF1). Recent studies suggest that muscle atrophy caused by denervation is associated with reduced expression of the nuclear cofactor peroxisome proliferator-activated receptor-γ coactivator (PGC)-1β and that PGC-1β may be a repressor of the atrogin-1 and MuRF1 genes. The influence of other muscle-wasting conditions on the expression of PGC-1β is not known. We tested the influence of sepsis and glucocorticoids on PGC-1β and examined the potential link between downregulated PGC-1β expression and upregulated atrogin-1 and MuRF1 expression in skeletal muscle. Sepsis in rats and mice and treatment with dexamethasone resulted in downregulated expression of PGC-1β and increased expression of atrogin-1 and MuRF1 in the fast-twitch extensor digitorum longus muscle, with less pronounced changes in the slow-twitch soleus muscle. In additional experiments, adenoviral gene transfer of PGC-1β into cultured C2C12 myotubes resulted in a dose-dependent decrease in atrogin-1 and MuRF1 mRNA levels. Treatment of cultured C2C12 myotubes with dexamethasone or PGC-1β small interfering RNA (siRNA) resulted in downregulated PGC-1β expression and increased protein degradation. Taken together, our results suggest that sepsis- and glucocorticoid-induced muscle wasting may, at least in part, be regulated by decreased expression of the nuclear cofactor PGC-1β.
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Affiliation(s)
- Michael J Menconi
- Departmentof Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 2215, USA
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López-Menduiña M, Martín AI, Castillero E, Villanúa MA, López-Calderón A. Systemic IGF-I administration attenuates the inhibitory effect of chronic arthritis on gastrocnemius mass and decreases atrogin-1 and IGFBP-3. Am J Physiol Regul Integr Comp Physiol 2010; 299:R541-51. [PMID: 20519361 DOI: 10.1152/ajpregu.00211.2010] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Adjuvant arthritis is an animal model of rheumatoid arthritis that decreases liver and circulating IGF-I as well as skeletal muscle mass. The aim of this work was to elucidate whether IGF-I administration was able to prevent the effect of arthritis on body weight and on two skeletal muscles, gastrocnemius and soleus. On day 4 after adjuvant injection, control and arthritic rats were treated with IGF-I (100 microg/kg s.c.) two times a day, until day 15 when all rats were killed. Arthritis decreased body weight gain and gastrocnemius weight. In arthritic rats, IGF-I treatment increased body weight gain and gastrocnemius weight, without modifying food intake or the external signs of arthritis. Arthritis increased atrogin-1 and muscle ring finger 1 (MuRF1) gene expression in the gastrocnemius and to a lesser extent in the soleus muscle. IGF-I attenuated the arthritis-induced increase in atrogin-1 and MuRF1 expression in the gastrocnemius, whereas it did not modify the expression of these genes in the soleus muscle. Arthritis also increased IGF-binding protein (IGBP)-3 and IGFBP-5 gene expression in gastrocnemius and soleus, whereas IGF-I administration decreased IGFBP-3, but not IGFBP-5, gene expression in both muscles. In both groups of arthritic rats and in control rats treated with IGF-I, proliferating cell nuclear antigen and myogenic differentiation proteins were increased in the gastrocnemius. These data suggest that the inhibitory effect of chronic arthritis on skeletal muscle is higher in fast glycolytic than in slow oxidative muscle and that IGF-I administration attenuates this effect and decreases atrogin-1 and IGFBP-3 gene expression.
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Affiliation(s)
- María López-Menduiña
- Faculty of Medicine, Department of Physiology, Complutense University of Madrid, Madrid, Spain
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Lenaers E, De Feyter HM, Hoeks J, Schrauwen P, Schaart G, Nabben M, Nicolay K, Prompers JJ, Hesselink MKC. Adaptations in mitochondrial function parallel, but fail to rescue, the transition to severe hyperglycemia and hyperinsulinemia: a study in Zucker diabetic fatty rats. Obesity (Silver Spring) 2010; 18:1100-7. [PMID: 19875988 DOI: 10.1038/oby.2009.372] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Cross-sectional human studies have associated mitochondrial dysfunction to type 2 diabetes. We chose Zucker diabetic fatty (ZDF) rats as a model of progressive insulin resistance to examine whether intrinsic mitochondrial defects are required for development of type 2 diabetes. Muscle mitochondrial function was examined in 6-, 12-, and 19-week-old ZDF (fa/fa) and fa/+ control rats (n = 8-10 per group) using respirometry with pyruvate, glutamate, and palmitoyl-CoA as substrates. Six-week-old normoglycemic-hyperinsulinemic fa/fa rats had reduced mitochondrial fat oxidative capacity. Adenosine diphosphate (ADP)-driven state 3 and carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP)-stimulated state uncoupled (state u) respiration on palmitoyl-CoA were lower compared to controls (62.3 +/- 9.5 vs. 119.1 +/- 13.8 and 87.8 +/- 13.3 vs. 141.9 +/- 14.3 nmol O(2)/mg/min.). Pyruvate oxidation in 6-week-old fa/fa rats was similar to controls. Remarkably, reduced fat oxidative capacity in 6-week-old fa/fa rats was compensated for by an adaptive increase in intrinsic mitochondrial function at week 12, which could not be maintained toward week 19 (140.9 +/- 11.2 and 57.7 +/- 9.8 nmol O(2)/mg/min, weeks 12 and 19, respectively), whereas hyperglycemia had developed (13.5 +/- 0.6 and 16.1 +/- 0.3 mmol/l, weeks 12 and 19, respectively). This mitochondrial adaptation failed to rescue the progressive development of insulin resistance in fa/fa rats. The transition of prediabetes state toward advanced hyperglycemia and hyperinsulinemia was accompanied by a blunted increase in uncoupling protein-3 (UCP3). Thus, in ZDF rats insulin resistance develops progressively in the absence of mitochondrial dysfunction. In fact, improved mitochondrial capacity in hyperinsulinemic hyperglycemic rats does not rescue the progression toward advanced stages of insulin resistance.
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MESH Headings
- Adaptation, Physiological/physiology
- Adenine Nucleotide Translocator 1/metabolism
- Animals
- Diabetes Mellitus, Experimental/complications
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Experimental/pathology
- Diabetes Mellitus, Experimental/physiopathology
- Hyperglycemia/complications
- Hyperglycemia/metabolism
- Hyperglycemia/physiopathology
- Hyperinsulinism/complications
- Hyperinsulinism/metabolism
- Hyperinsulinism/physiopathology
- Ion Channels/metabolism
- Male
- Mitochondria, Muscle/metabolism
- Mitochondria, Muscle/pathology
- Mitochondria, Muscle/physiology
- Mitochondrial Proteins/metabolism
- Muscle Fibers, Skeletal/metabolism
- Muscle Fibers, Skeletal/pathology
- Obesity/complications
- Obesity/metabolism
- Obesity/pathology
- Obesity/physiopathology
- Oxidation-Reduction
- Oxygen Consumption/physiology
- Protein Carbonylation/physiology
- Rats
- Rats, Zucker
- Severity of Illness Index
- Uncoupling Protein 3
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Affiliation(s)
- Ellen Lenaers
- NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Centre, Maastricht, The Netherlands
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McNicol FJ, Hoyland JA, Cooper RG, Carlson GL. Skeletal muscle contractile properties and proinflammatory cytokine gene expression in human endotoxaemia. Br J Surg 2009; 97:434-42. [DOI: 10.1002/bjs.6868] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
Background
Muscle dysfunction associated with sepsis contributes to morbidity and mortality but the underlying mechanisms are unclear. This study examined whether muscle weakness relates to an intrinsic defect in contraction, or to central mechanisms associated with acute illness, and whether systemic endotoxaemia induces changes in gene expression for proinflammatory cytokines within human muscle in vivo.
Methods
In this experimental study, 12 healthy men received intravenous Escherichia coli lipopolysaccharide (LPS, 4 ng/kg) or saline (control). Voluntary and electrically stimulated quadriceps contraction, and tumour necrosis factor (TNF) α mRNA expression in quadriceps muscle biopsies were studied before and after the infusion.
Results
Endotoxaemia induced transient weakness of voluntary quadriceps contraction, equivalent to a 7·8 (95 per cent confidence interval 2·1 to 13·5) per cent reduction in contractile force at 180 min (P = 0·027) and a 9·0 (5·2 to 12·8) per cent reduction at 300 min (P = 0·008). Electrically stimulated contraction was unaffected. LPS administration resulted in an apparent fibre-specific induction of TNF-α mRNA.
Conclusion
Endotoxaemia results in a reduction in voluntary muscle contractile force without an apparent defect in stimulated muscle contraction. Loss of volition may be a more important factor than intrinsic dysfunction in acute sepsis-associated human muscle weakness.
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Affiliation(s)
- F J McNicol
- Infection, Injury and Inflammation Research Group, Salford Royal NHS Foundation Trust, Hope Hospital, Salford, UK
| | - J A Hoyland
- University of Manchester School of Clinical and Laboratory Sciences, Manchester, UK
| | - R G Cooper
- Infection, Injury and Inflammation Research Group, Salford Royal NHS Foundation Trust, Hope Hospital, Salford, UK
| | - G L Carlson
- Infection, Injury and Inflammation Research Group, Salford Royal NHS Foundation Trust, Hope Hospital, Salford, UK
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Murton AJ, Alamdari N, Gardiner SM, Constantin-Teodosiu D, Layfield R, Bennett T, Greenhaff PL. Effects of endotoxaemia on protein metabolism in rat fast-twitch skeletal muscle and myocardium. PLoS One 2009; 4:e6945. [PMID: 19759896 PMCID: PMC2736646 DOI: 10.1371/journal.pone.0006945] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2009] [Accepted: 07/29/2009] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND It is unclear if the rat myocardium undergoes the same rapid reductions in protein content that are classically observed in fast-twitch skeletal muscle during endotoxaemia. METHODOLOGY/PRINCIPAL FINDINGS To investigate this further, and to determine if there is any divergence in the response of skeletal muscle and myocardium in the mechanisms that are thought to be largely responsible for eliciting changes in protein content, Sprague Dawley rats were implanted with vascular catheters and administered lipopolysaccharide (LPS; 150 microg kg(-1) h(-1)) intravenously for 2 h, 6 h or 24 h (saline administered control animals were also included), after which the extensor digitorum longus (EDL) and myocardium were removed under terminal anaesthesia. The protein-to-DNA ratio, a marker of protein content, was significantly reduced in the EDL following 24 h LPS administration (23%; P<0.05), but was no different from controls in the myocardium. At the same time point, a significant increase in MAFbx/atrogin-1 and MuRF1 mRNA (3.7+/-0.7- and 19.5+/-1.9-fold increase vs. controls, respectively; P<0.05), in addition to protein levels of alpha1-3, 5-7 subunits of the 20S proteasome, were observed in EDL but not myocardium. In contrast, elevations in phosphorylation of p70 S6K residues Thr(421)/Ser(424), and 4E-BP1 residues Thr(37)/Thr(46) (P<0.05), consistent with an elevation in translation initiation, were seen exclusively in the myocardium of LPS-treated animals. CONCLUSIONS/SIGNIFICANCE In summary, these findings suggest that the myocardium does not undergo the same catabolic response as skeletal muscle during early endotoxaemia, partly due to the absence of transcriptional and signalling events in the myocardium typically associated with increased muscle proteolysis and the suppression of protein synthesis.
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Affiliation(s)
- Andrew J Murton
- Centre for Integrated Systems Biology and Medicine, School of Biomedical Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, UK.
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Treatment with TNF-alpha and IFN-gamma alters the activation of SER/THR protein kinases and the metabolic response to IGF-I in mouse c2c12 myogenic cells. Cell Mol Biol Lett 2009; 15:13-31. [PMID: 19685010 PMCID: PMC6275934 DOI: 10.2478/s11658-009-0033-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2009] [Accepted: 08/06/2009] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The aim of this study was to compare the effects of TNF-alpha, IL-1beta and IFN-gamma on the activation of protein kinase B (PKB), p70(S6k), mitogen-activated protein kinase (MAPK) and p90( rsk ), and on IGF-I-stimulated glucose uptake and protein synthesis in mouse C2C12 myotubes. 100 nmol/l IGF-I stimulated glucose uptake in C2C12 myotubes by 198.1% and 10 ng/ml TNF-alpha abolished this effect. Glucose uptake in cells differentiated in the presence of 10 ng/ml IFN-gamma increased by 167.2% but did not undergo significant further modification upon the addition of IGF-I. IGF-I increased the rate of protein synthesis by 249.8%. Neither TNF-alpha nor IFN-gamma influenced basal protein synthesis, but both cytokines prevented the IGF-I effect. 10 ng/ml IL-1beta did not modify either the basal or IGF-I-dependent glucose uptake and protein synthesis. With the exception of TNF-alpha causing an 18% decrease in the level of PKB protein, the cellular levels of PKB, p70(S6k), p42(MAPK), p44(MAPK) and p90( rsk ) were not affected by the cytokines. IGF-I caused the phosphorylation of PKB (an approximate 8-fold increase above the basal value after 40 min of IGF-I treatment), p42(MAPK) (a 2.81-fold increase after 50 min), and the activation of p70(S6k) and p90( rsk ), manifesting as gel mobility retardation. In cells differentiated in the presence of TNF-alpha or IFN-gamma, this IGF-I-mediated PKB and p70(S6k) phosphorylation was significantly diminished, and the increase in p42(MAPK) and p90( rsk ) phosphorylation was prevented. The basal p42(MAPK) phosphorylation in C2C12 cells treated with IFN-gamma was high and comparable with the activation of this kinase by IGF-I. Pretreatment of myogenic cells with IL-1beta did not modify the IGF-I-stimulated phosphorylation of PKB, p70(S6k), p42(MAPK) and p90( rsk ). IN CONCLUSION i) TNF-alpha and IFN-gamma, but not IL-1beta, if present in the extracellular environment during C2C12 myoblast differentiation, prevent the stimulatory action of IGF-I on protein synthesis. ii) TNF-alpha- and IFN-gamma-induced IGF-I resistance of protein synthesis could be associated with the decreased phosphorylation of PKB and p70(S6k). iii) The activation of glucose uptake in C2C12 myogenic cells treated with IFN-gamma is PKB independent. iv) The similar effects of TNF-alpha and IFN-gamma on the signalling and action of IGF-I on protein synthesis in myogenic cells could suggest the involvement of both of these cytokines in protein loss in skeletal muscle.
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Shi H, Scheffler JM, Zeng C, Pleitner JM, Hannon KM, Grant AL, Gerrard DE. Mitogen-activated protein kinase signaling is necessary for the maintenance of skeletal muscle mass. Am J Physiol Cell Physiol 2009; 296:C1040-8. [DOI: 10.1152/ajpcell.00475.2008] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The signal transduction cascades that maintain muscle mass remain to be fully defined. Herein, we report that inhibition of extracellular signal-regulated kinase 1/2 (ERK1/2) signaling in vitro decreases myotube size and protein content after 3-day treatment with a MEK inhibitor. Neither p38 nor JNK inhibitors had any effect on myotube size or morphology. ERK1/2 inhibition also upregulated gene transcription of atrogin-1 and muscle-specific RING finger protein 1 and downregulated the phosphorylation of Akt and its downstream kinases. Forced expression of enhanced green fluorescent protein-tagged MAPK phosphatase 1 (MKP-1) in soleus and gastrocnemius muscles decreased both fiber size and reporter activity. This atrophic effect of MKP-1 was time dependent. Analysis of the reporter activity in vivo revealed that the activities of nuclear factor-κB and 26S proteasome were differentially activated in slow and fast muscles, suggesting muscle type-specific mechanisms may be utilized. Together, these findings suggest that MAPK signaling is necessary for the maintenance of skeletal muscle mass because inhibition of these signaling cascades elicits muscle atrophy in vitro and in vivo.
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44
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Turpin SM, Ryall JG, Southgate R, Darby I, Hevener AL, Febbraio MA, Kemp BE, Lynch GS, Watt MJ. Examination of 'lipotoxicity' in skeletal muscle of high-fat fed and ob/ob mice. J Physiol 2009; 587:1593-605. [PMID: 19204053 DOI: 10.1113/jphysiol.2008.166033] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Excess lipid accumulation resulting from an elevated supply of plasma fatty acids is linked to the pathogenesis of the metabolic syndrome and heart disease. The term 'lipotoxicity' was coined to describe how lipid accumulation leads to cellular dysfunction and death in non-adipose tissues including the heart, pancreas and liver. While lipotoxicity has been shown in cultured skeletal muscle cells, the degree of lipotoxicity in vivo and the functional consequences are unresolved. We studied three models of fatty acid overload in male mice: 5 h Intralipid((R)) and heparin infusion, prolonged high fat feeding (HFF) and genetic obesity induced by leptin deficiency (ob/ob mice). Markers of apoptosis, proteolysis and autophagy were assessed as readouts of lipotoxicity. The Intralipid((R)) infusion increased caspase 3 activity in skeletal muscle, demonstrating that enhancing fatty acid flux activates pro-apoptotic pathways. HFF and genetic obesity increased tissue lipid content but did not influence apoptosis. Gene array analysis revealed that HFF reduced the expression of 31 pro-apoptotic genes. Markers of autophagy (LC3beta and beclin-1 expression) were unaffected by HFF and were associated with enhanced Bcl(2) protein expression. Proteolytic activity was similarly unaffected by HFF or in ob/ob mice. Thus, contrary to our previous findings in muscle culture in vitro and in other non-adipose tissues in vivo, lipid overload did not induce apoptosis, autophagy or proteolysis in skeletal muscle. A broad transcriptional suppression of pro-apoptotic proteins may explain this resistance to lipid-induced cell death in skeletal muscle.
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Affiliation(s)
- S M Turpin
- St Vincent's Institute of Medical Research and the Department of Medicine, University of Melbourne, Fitzroy, Australia
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Narkar VA, Downes M, Yu RT, Embler E, Wang YX, Banayo E, Mihaylova MM, Nelson MC, Zou Y, Juguilon H, Kang H, Shaw RJ, Evans RM. AMPK and PPARdelta agonists are exercise mimetics. Cell 2008; 134:405-15. [PMID: 18674809 PMCID: PMC2706130 DOI: 10.1016/j.cell.2008.06.051] [Citation(s) in RCA: 1183] [Impact Index Per Article: 73.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2007] [Revised: 04/23/2008] [Accepted: 06/20/2008] [Indexed: 10/21/2022]
Abstract
The benefits of endurance exercise on general health make it desirable to identify orally active agents that would mimic or potentiate the effects of exercise to treat metabolic diseases. Although certain natural compounds, such as reseveratrol, have endurance-enhancing activities, their exact metabolic targets remain elusive. We therefore tested the effect of pathway-specific drugs on endurance capacities of mice in a treadmill running test. We found that PPARbeta/delta agonist and exercise training synergistically increase oxidative myofibers and running endurance in adult mice. Because training activates AMPK and PGC1alpha, we then tested whether the orally active AMPK agonist AICAR might be sufficient to overcome the exercise requirement. Unexpectedly, even in sedentary mice, 4 weeks of AICAR treatment alone induced metabolic genes and enhanced running endurance by 44%. These results demonstrate that AMPK-PPARdelta pathway can be targeted by orally active drugs to enhance training adaptation or even to increase endurance without exercise.
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Affiliation(s)
- Vihang A Narkar
- Gene Expression Laboratory, Salk Institute, La Jolla, CA 92037, USA
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Effects of chronic sepsis on contractile properties of fast twitch muscle in an experimental model of critical illness neuromyopathy in the rat. Crit Care Med 2008; 36:1855-63. [PMID: 18520643 DOI: 10.1097/ccm.0b013e318176106b] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Critical illness polyneuromyopathy has been extensively studied in various animal models regarding electrophysiological aspects or molecular mechanisms involved in its physiopathology; however, little data are available on its main clinical feature, that is, muscular weakness. We have studied the effects of chronic sepsis in rats with special consideration to contractile and neuromuscular blockade properties in relation with the level of messenger RNA (mRNA) coding for ryanodine and acetylcholine receptors. DESIGN This was an experimental animal study. SETTING This study was conducted at a university laboratory. SUBJECTS Subjects consisted of Wistar rats. INTERVENTIONS Chronic sepsis was achieved by cecal ligation and needle perforation. Ten days after surgery, fast twitch extensor digitorum longus was excised for extraction and assays of mRNA coding for ryanodine and acetylcholine receptor subunits and contralateral muscle was tested in vivo on a mechanical bench. A fatigability index was measured and neuromuscular blockade properties using atracurium were evaluated. MEASUREMENTS AND MAIN RESULTS A decrease in active force developed by extensor digitorum longus associated with an increase in passive force is induced by chronic sepsis. Maximal force at optimal length during twitch contraction was significantly reduced (0.25 +/- 0.09 N vs. 0.17 +/- 0.06 N); contraction and relaxation speeds were higher as shown by the decrease of respective time constants (3.75 +/- 0.01 msec vs. 2.70 +/- 0.0 msec, 10.76 +/- 0.03 msec vs. 7.62 +/- 0.03 msec) in the control group compared with the septic group. Fatigability index was significantly lower (23 +/- 0.11% vs. 59 +/- 0.19%) in septic rats. These rats also showed quicker blockade and shorter recovery after atracurium administration. Sepsis induced a significant increase of the expression of ryanodine receptor (RyR) RyR1 along with a steady expression of RyR3 mRNA, leading to a 5.6-fold increase of RyR1/RyR3 ratio with a steadiness of mRNA corresponding to acetylcholine-receptors. CONCLUSIONS Chronic inflammation and sepsis induced a decrease in contractile performances of extensor digitorum longus along with accelerated kinetics of atracurium possibly induced by modified expression of RyR1 receptors and not acetylcholine-receptors.
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Systemic inflammatory response syndrome increases immobility-induced neuromuscular weakness. Crit Care Med 2008; 36:910-6. [PMID: 18431280 DOI: 10.1097/ccm.0b013e3181659669] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Inflammation and immobility are comorbid etiological factors inducing muscle weakness in critically ill patients. This study establishes a rat model to examine the effect of inflammation and immobilization alone and in combination on muscle contraction, histology, and acetylcholine receptor regulation. DESIGN Prospective, randomized, experimental study. SETTING Animal laboratory of a university hospital. SUBJECTS Sprague-Dawley rats. INTERVENTIONS To produce systemic inflammation, rats (n = 34) received three consecutive intravenous injections of Corynebacterium parvum on days 0, 4, and 8. Control rats (n = 21) received saline. Both groups were further divided to have one hind limb either immobilized by pinning of knee and ankle joints or sham-immobilized (surgical leg). The contralateral nonsurgical leg of each animal served as control (nonsurgical leg). MEASUREMENTS AND MAIN RESULTS After 12 days, body weight and muscle mass were significantly reduced in all C. parvum animals compared with saline-injected rats. Immobilization led to local muscle atrophy. Normalized to muscle mass, tetanic contraction was reduced in the surgical leg after immobilization (7.64 +/- 1.91 N/g) and after inflammation (8.71 +/- 2.0 N/g; both p < .05 vs. sham immobilization and saline injection, 11.03 +/- 2.26 N/g). Histology showed an increase in inflammatory cells in all C. parvum-injected animals. Immobilization in combination with C. parvum injection had an additive effect on inflammation. Acetylcholine receptors were increased in immobilized muscles and in all muscles of C. parvum-injected animals. CONCLUSIONS The muscle weakness in critically ill patients can be replicated in our novel rat model. Inflammation and immobilization independently lead to muscle weakness.
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Giannesini B, Izquierdo M, Dalmasso C, Le Fur Y, Cozzone PJ, Verleye M, Le Guern ME, Gillardin JM, Bendahan D. Endotoxemia does not limit energy supply in exercising rat skeletal muscle. Muscle Nerve 2008; 37:496-504. [PMID: 18260074 DOI: 10.1002/mus.20966] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Although depletion in high-energy phosphorylated compounds and mitochondrial impairment have been reported in septic skeletal muscle at rest, their impact on energy metabolism has not been documented during exercise. In this study we aimed to investigate strictly gastrocnemius muscle function non-invasively, using magnetic resonance techniques in endotoxemic rats. Endotoxemia was induced by injecting animals intraperitoneally at t(0) and t(0) + 24 h with Klebsiella pneumoniae lipopolysaccharides (at 3 mg kg(-1)). Investigations were performed at t(0) + 48 h during a transcutaneous electrical stimulation protocol consisting of 5.7 min of repeated isometric contractions at a frequency of 3.3 HZ. Endotoxin treatment produced a depletion in basal phosphocreatine content and a pronounced reduction in oxidative adenosine triphosphate (ATP) synthesis capacity, whereas the resting ATP concentration remained unchanged. During the stimulation period, endotoxemia caused a decrease in force-generating capacity that was fully accounted for by the loss of muscle mass. It further induced an acceleration of glycolytic ATP production and an increased accumulation of adenosine diphosphate (ADP, an important mitochondrial regulator) that allowed a near-normal rate of oxidative ATP synthesis. Finally, endotoxemia did not affect the total rate of ATP production or the ATP cost of contraction throughout the whole stimulation period. These data demonstrate that, in an acute septic phase, metabolic alterations in resting muscle do not impact energy supply in exercising muscle, likely as a result of adaptive mechanisms.
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Affiliation(s)
- Benoit Giannesini
- Centre de Résonance Magnétique Biologique et Médicale (CRMBM), UMR CNRS 6612, Faculté de Médecine de Marseille, Marseille, France.
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Yu Z, Li P, Zhang M, Hannink M, Stamler JS, Yan Z. Fiber type-specific nitric oxide protects oxidative myofibers against cachectic stimuli. PLoS One 2008; 3:e2086. [PMID: 18461174 PMCID: PMC2361191 DOI: 10.1371/journal.pone.0002086] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2007] [Accepted: 03/25/2008] [Indexed: 11/18/2022] Open
Abstract
Oxidative skeletal muscles are more resistant than glycolytic muscles to cachexia caused by chronic heart failure and other chronic diseases. The molecular mechanism for the protection associated with oxidative phenotype remains elusive. We hypothesized that differences in reactive oxygen species (ROS) and nitric oxide (NO) determine the fiber type susceptibility. Here, we show that intraperitoneal injection of endotoxin (lipopolysaccharide, LPS) in mice resulted in higher level of ROS and greater expression of muscle-specific E3 ubiqitin ligases, muscle atrophy F-box (MAFbx)/atrogin-1 and muscle RING finger-1 (MuRF1), in glycolytic white vastus lateralis muscle than in oxidative soleus muscle. By contrast, NO production, inducible NO synthase (iNos) and antioxidant gene expression were greatly enhanced in oxidative, but not in glycolytic muscles, suggesting that NO mediates protection against muscle wasting. NO donors enhanced iNos and antioxidant gene expression and blocked cytokine/endotoxin-induced MAFbx/atrogin-1 expression in cultured myoblasts and in skeletal muscle in vivo. Our studies reveal a novel protective mechanism in oxidative myofibers mediated by enhanced iNos and antioxidant gene expression and suggest a significant value of enhanced NO signaling as a new therapeutic strategy for cachexia.
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Affiliation(s)
- Zengli Yu
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Ping Li
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Mei Zhang
- Duke-NUS Graduate Medical School, Singapore, Singapore
| | - Mark Hannink
- Department of Biochemistry, Life Science Center, University of Missouri-Columbia, Columbia, Missouri, United States of America
| | - Jonathan S. Stamler
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Zhen Yan
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America
- Duke-NUS Graduate Medical School, Singapore, Singapore
- * E-mail:
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50
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Abstract
Sir David Cuthbertson was the first to define metabolic alterations in post-aggression syndrome (PAS). From basic measurements of nitrogen loss and total protein synthesis/degradation, the current research has moved to genomics, proteomics and metabolomics. In this respect, first evidence was accumulated for the influence of acute catabolism, immobilisation by bed rest and sarcopenia of old age on the muscle-cell genome and proteome. Moreover, in post-aggression syndrome specific amino acids such as glutamine, arginine, glycine, taurine, tryptophan and cysteine are used for cell and immune modulation. Our laboratory has focused on the regulative capacity of glutamine. Glutamine deficiency as found in post-aggression syndrome reduces lymphocyte proliferation, alters monocyte/macrophage activity, decreases the formation of heat-shock proteins, stimulates cell apoptosis, shifts the cellular redox potential by altering the glutathione synthesis and increases the activity of the AMPK system. Investigating the molecular effect of glutamine on Hsp 70 induction, we tested the glutamine dependence on the formation of transfer-RNA and of heat-shock factor 1 (HSF 1), and on transcription and translation of Hsp 70. We could demonstrate that glutamine stabilises the mRNA of Hsp 70 thereby prolonging its half-life. The lecture also discusses the principal molecular targets of administered arginine, glycine, cysteine, taurine and tryptophan.
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Affiliation(s)
- Erich Roth
- Department of Surgery, Research Laboratories, Medical University of Vienna, Austria.
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