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Hanson AM, Young MH, Harrison BC, Zhou X, Han HQ, Stodieck LS, Ferguson VL. Inhibiting myostatin signaling partially mitigates structural and functional adaptations to hindlimb suspension in mice. NPJ Microgravity 2023; 9:2. [PMID: 36646717 PMCID: PMC9842652 DOI: 10.1038/s41526-022-00233-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 10/12/2022] [Indexed: 01/18/2023] Open
Abstract
Novel treatments for muscle wasting are of significant value to patients with disease states that result in muscle weakness, injury recovery after immobilization and bed rest, and for astronauts participating in long-duration spaceflight. We utilized an anti-myostatin peptibody to evaluate how myostatin signaling contributes to muscle loss in hindlimb suspension. Male C57BL/6 mice were left non-suspended (NS) or were hindlimb suspended (HS) for 14 days and treated with a placebo vehicle (P) or anti-myostatin peptibody (D). Hindlimb suspension (HS-P) resulted in rapid and significantly decreased body mass (-5.6% by day 13) with hindlimb skeletal muscle mass losses between -11.2% and -22.5% and treatment with myostatin inhibitor (HS-D) partially attenuated these losses. Myostatin inhibition increased hindlimb strength with no effect on soleus tetanic strength. Soleus mass and fiber CSA were reduced with suspension and did not increase with myostatin inhibition. In contrast, the gastrocnemius showed histological evidence of wasting with suspension that was partially mitigated with myostatin inhibition. While expression of genes related to protein degradation (Atrogin-1 and Murf-1) in the tibialis anterior increased with suspension, these atrogenes were not significantly reduced by myostatin inhibition despite a modest activation of the Akt/mTOR pathway. Taken together, these findings suggest that myostatin is important in hindlimb suspension but also motivates the study of other factors that contribute to disuse muscle wasting. Myostatin inhibition benefitted skeletal muscle size and function, which suggests therapeutic potential for both spaceflight and terrestrial applications.
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Affiliation(s)
- Andrea M. Hanson
- grid.266190.a0000000096214564Aerospace Engineering Sciences, BioServe Space Technologies, University of Colorado, Boulder, CO USA
| | - Mary H. Young
- grid.266190.a0000000096214564Aerospace Engineering Sciences, BioServe Space Technologies, University of Colorado, Boulder, CO USA
| | - Brooke C. Harrison
- grid.266190.a0000000096214564Department of Molecular Cellular and Developmental Biology, University of Colorado, Boulder, CO USA
| | - Xiaolan Zhou
- grid.417886.40000 0001 0657 5612Amgen Inc., Thousand Oaks, CA USA ,Present Address: AliveGen USA Inc., Thousand Oaks, CA USA
| | - H. Q. Han
- grid.417886.40000 0001 0657 5612Amgen Inc., Thousand Oaks, CA USA ,Present Address: AliveGen USA Inc., Thousand Oaks, CA USA
| | - Louis S. Stodieck
- grid.266190.a0000000096214564Aerospace Engineering Sciences, BioServe Space Technologies, University of Colorado, Boulder, CO USA
| | - Virginia L. Ferguson
- grid.266190.a0000000096214564Aerospace Engineering Sciences, BioServe Space Technologies, University of Colorado, Boulder, CO USA ,grid.266190.a0000000096214564Department of Mechanical Engineering, University of Colorado, Boulder, CO USA ,grid.266190.a0000000096214564BioFrontiers Institute, University of Colorado, Boulder, CO USA
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2
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Fathi M, Saeedyan S, Kaoosi M. Gamma-amino butyric acid (GABA) supplementation alleviates dexamethasone treatment-induced oxidative stress and inflammation response in broiler chickens. Stress 2023; 26:2185861. [PMID: 36861448 DOI: 10.1080/10253890.2023.2185861] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/03/2023] Open
Abstract
This experiment was conducted to investigate the effect of Gamma-amino butyric acid (GABA) on growth performance, serum and liver antioxidant status, inflammation response and hematological changes, in male broiler chickens under experimentally induced stress via in-feed dexamethasone (DEX). A total of 300 male chicks (Ross 308) on day 7 after hatching, were randomly selected into four groups which were positive control group (PC, without any treatment), negative control (NC, with 1 mg/kg DEX), a third group received 1 mg/kg DEX and 100 mg/kg GABA (DG +) and the last one was (DG ++) which received 1 mg/kg DEX and 200 mg/kg GABA. Each group has five replicates (15 birds/replicate). Dietary GABA modulated DEX-induced adverse effects on body weight, feed intake, and feed conversion ratio. The DEX-induced effect of serum levels of IL-6 and IL-10 was reduced by dietary GABA supplementation. The activity of serum and liver superoxide dismutase, catalase, glutathione peroxidase were enhanced and malondialdehyde was reduced by GABA supplementation. The serum levels of total cholesterol & triglyceride were higher while low-density lipoprotein & high-density lipoprotein were lower in GABA groups than NC group. GABA supplementation also significantly decreased the heterophil, heterophil/lymphocyte ratio and elevated the activities of aspartate aminotransferase (AST), alanine transaminase (ALT) and alkaline phosphatase (ALP) than NC group. In conclusion, dietary GABA supplementation can alleviate DEX stress-induced oxidative stress and inflammation response.
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Affiliation(s)
- Mokhtar Fathi
- Department of Animal Science, Payam Noor University, Tehran, Iran
| | | | - Majid Kaoosi
- Department of Biology, Payam Noor University, Tehran, Iran
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3
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A Novel Muscle Atrophy Mechanism: Myocyte Degeneration Due to Intracellular Iron Deprivation. Cells 2022; 11:cells11182853. [PMID: 36139428 PMCID: PMC9497220 DOI: 10.3390/cells11182853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 09/06/2022] [Accepted: 09/06/2022] [Indexed: 11/30/2022] Open
Abstract
Muscle atrophy is defined as the progressive degeneration or shrinkage of myocytes and is triggered by factors such as aging, cancer, injury, inflammation, and immobilization. Considering the total amount of body iron stores and its crucial role in skeletal muscle, myocytes may have their own iron regulation mechanism. Although the detrimental effects of iron overload or iron deficiency on muscle function have been studied, the molecular mechanism of iron-dependent muscle atrophy has not been elucidated. Using human muscle tissues and in the mouse rotator cuff tear model, we confirmed an association between injury-induced iron depletion in myocytes and muscle atrophy. In differentiated C2C12 myotubes, the effects of iron deficiency on myocytes and the molecular mechanism of muscle atrophy by iron deficiency were evaluated. Our study revealed that the lower iron concentration in injured muscle was associated with the upregulation of ferroportin, an iron exporter that transports iron out of cells. Ferroportin expression was increased by hypoxia-inducible factor 1α (HIF1α), which is activated by muscle injury, and its expression is controlled by HIF1 inhibitor treatment. Iron deprivation caused myocyte loss and a marked depletion of mitochondrial membrane potential leading to muscle atrophy, together with increased levels of myostatin, the upstream regulator of atrogin1 and muscle RING-finger protein-1 (MuRF1). Myostatin expression under iron deficiency was mediated by an orphan nuclear receptor, dosage-sensitive sex reversal-adrenal hypoplasia congenita critical region on the X chromosome (DAX1).
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4
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Kim B, Sasaki A, Murphy K, Matthews SG. DNA methylation signatures in human neonatal blood following maternal antenatal corticosteroid treatment. Transl Psychiatry 2022; 12:132. [PMID: 35354798 PMCID: PMC8967826 DOI: 10.1038/s41398-022-01902-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 03/01/2022] [Accepted: 03/15/2022] [Indexed: 11/09/2022] Open
Abstract
Antenatal corticosteroids (ACS) are used to treat women at risk of preterm birth to improve neonatal survival. Though affected children may be at long-term risk of neurobehavioural disorders, the driving mechanisms remain unknown. Animal studies have shown that ACS exposure can lead to overlapping changes in DNA methylation between the blood and the brain, identifying gene pathways for neurodevelopment, which highlights the potential to examine peripheral blood as a surrogate for inaccessible human brain tissue. We hypothesized that differential methylation will be identified in blood of term-born neonates following ACS. Mother-infant dyads that received ACS were retrospectively identified through the Ontario Birth Study at Sinai Health Complex and matched to untreated controls for maternal age, BMI, parity and foetal sex (n = 14/group). Genome-wide methylation differences were examined at single-nucleotide resolution in DNA extracted from dried bloodspot cards using reduced representative bisulfite sequencing approaches. 505 differentially methylated CpG sites (DMCs) were identified, wherein 231 were hypermethylated and 274 were hypomethylated. These sites were annotated to 219 genes, of which USP48, SH3PXD2A, NTM, CAMK2N2, MAP6D1 were five of the top ten genes with known neurological function. Collectively, the set of hypermethylated genes were enriched for pathways of transcription regulation, while pathways of proteasome activity were enriched among the set of hypomethylated genes. This study is the first to identify DNA methylation changes in human neonatal blood following ACS. Understanding the epigenetic changes that occur in response to ACS will support future investigations to delineate the effects of prenatal glucocorticoid exposure on human development.
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Affiliation(s)
- Bona Kim
- Department of Physiology, University of Toronto, Toronto, ON, Canada.
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, ON, Canada.
| | - Aya Sasaki
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, ON, Canada
| | - Kellie Murphy
- Department of Obstetrics & Gynecology, University of Toronto, Toronto, ON, Canada
| | - Stephen G Matthews
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, ON, Canada
- Department of Obstetrics & Gynecology, University of Toronto, Toronto, ON, Canada
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5
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Wang XH, Mitch WE, Price SR. Pathophysiological mechanisms leading to muscle loss in chronic kidney disease. Nat Rev Nephrol 2022; 18:138-152. [PMID: 34750550 DOI: 10.1038/s41581-021-00498-0] [Citation(s) in RCA: 60] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2021] [Indexed: 12/16/2022]
Abstract
Loss of muscle proteins is a deleterious consequence of chronic kidney disease (CKD) that causes a decrease in muscle strength and function, and can lead to a reduction in quality of life and increased risk of morbidity and mortality. The effectiveness of current treatment strategies in preventing or reversing muscle protein losses is limited. The limitations largely stem from the systemic nature of diseases such as CKD, which stimulate skeletal muscle protein degradation pathways while simultaneously activating mechanisms that impair muscle protein synthesis and repair. Stimuli that initiate muscle protein loss include metabolic acidosis, insulin and IGF1 resistance, changes in hormones, cytokines, inflammatory processes and decreased appetite. A growing body of evidence suggests that signalling molecules secreted from muscle can enter the circulation and subsequently interact with recipient organs, including the kidneys, while conversely, pathological events in the kidney can adversely influence protein metabolism in skeletal muscle, demonstrating the existence of crosstalk between kidney and muscle. Together, these signals, whether direct or indirect, induce changes in the levels of regulatory and effector proteins via alterations in mRNAs, microRNAs and chromatin epigenetic responses. Advances in our understanding of the signals and processes that mediate muscle loss in CKD and other muscle wasting conditions will support the future development of therapeutic strategies to reduce muscle loss.
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Affiliation(s)
- Xiaonan H Wang
- Renal Division, Department of Medicine, Emory University, Atlanta, GA, USA
| | - William E Mitch
- Nephrology Division, Department of Medicine, Baylor College of Medicine, Houston, TX, USA
| | - S Russ Price
- Department of Biochemistry and Molecular Biology, Brody School of Medicine, East Carolina University, Greenville, NC, USA. .,Department of Internal Medicine, Brody School of Medicine, East Carolina University, Greenville, NC, USA.
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6
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Queiroz Júnior JRAD, Costa Pereira JPD, Pires LL, Maia CS. The Dichotomous Effect of Thiamine Supplementation on Tumorigenesis: A Systematic Review. Nutr Cancer 2021; 74:1942-1957. [PMID: 34854769 DOI: 10.1080/01635581.2021.2007962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The malignant neoplastic cell is characterized by its diverse metabolic changes. It occurs in order to maintain the high rate of proliferation. The possibility of new pharmacological targets has inserted tumor metabolism as a target for recent research, emphasizing the enzymatic activity of thiamin. This review aims to elucidate the behavior of thiamin against tumor development. This is a systematic review in which studies indexed in Pubmed, Scopus, SciELO and BVS were searched using the descriptors (Thiamin OR Vitamin B1) AND (Cancer OR Malignant neoplasia) AND (Tumor metabolism). Title and abstract were read. Duplicates, literary reviews, books, conference abstracts, editorials, and papers published prior to 2010 were eliminated. 23 records were included in this review. Low doses of thiamin have been shown to be enough to stimulate tumor growth. Another population studies has shown evidence of tumor regression after correction of vitamin B1 deficiency. There is an open path for the development of new research to better assess the influence of thiamin on cancer cells. Once the connections between thiamin and the metabolism of cancer cells are fully established, new opportunities for therapeutic intervention and dietary modification will appear to reduce the progression of the disease in patients with cancer.
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Affiliation(s)
| | | | - Leonardo Lucas Pires
- Department of Medical Sciences, Potiguar University, Natal, Rio Grande do Norte, Brazil
| | - Carina Scanoni Maia
- Department of Histology and Embryology, Federal University of Pernambuco, Recife, Pernambuco, Brazil
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7
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Speacht TL, Lang CH, Donahue HJ. Soluble RANKL exaggerates hindlimb suspension-induced osteopenia but not muscle protein balance. J Orthop Res 2021; 39:1860-1869. [PMID: 33222219 PMCID: PMC8140066 DOI: 10.1002/jor.24917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 11/02/2020] [Accepted: 11/19/2020] [Indexed: 02/04/2023]
Abstract
We examined the hypothesis that exaggerating unloading-induced bone loss using a combination of hindlimb suspension (HLS) and exogenous injections of receptor activator of nuclear factor-κB ligand (RANKL) also exaggerates gastrocnemius and quadriceps muscle loss. Forty, male C57Bl/6J mice (16 weeks) were subjected to HLS or normal ambulation (ground control, GC) for 14 days. Mice received three intraperitoneal injections of either human recombinant soluble RANKL or phosphate-buffered saline as control (n = 10/group) at 24 h intervals starting on Day 1 of HLS. GC + RANKL and HLS mice exhibited similar decreases in trabecular bone volume and density in both proximal tibias and distal femurs. However, RANKL affected trabecular number, separation, and connectivity density, while HLS decreased trabecular thickness. The combination of RANKL and HLS exacerbated these changes. Similarly, GC + RANKL and HLS mice saw comparable decreases in cortical bone volume, thickness, and strength in femur midshafts, and combination treatment exacerbated these changes. Plasma concentrations of P1NP were increased in both groups receiving RANKL, while CTX concentrations were unchanged. HLS decreased gastrocnemius weight and was associated with a reduction in global protein synthesis, and no change in proteasome activity. This change was correlated with a decrease in S6K1 and S6 phosphorylation, but no change in 4E-BP1 phosphorylation. Injection of RANKL did not alter gastrocnemius or quadriceps muscle protein metabolism in GC or HLS mice. Our results suggest that injection of soluble RANKL exacerbates unloading-induced bone loss, but not unloading-induced gastrocnemius or quadriceps muscle loss.
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Affiliation(s)
- Toni L. Speacht
- Department of Orthopaedics and Rehabilitation, The Pennsylvania State University, College of Medicine, Hershey, Pennsylvania, USA
| | - Charles H. Lang
- Department of Cellular and Molecular Physiology, The Pennsylvania State University, College of Medicine, Hershey, Pennsylvania, USA
| | - Henry J. Donahue
- Department of Orthopaedics and Rehabilitation, The Pennsylvania State University, College of Medicine, Hershey, Pennsylvania, USA,Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia, USA
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8
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Random errors in protein synthesis activate an age-dependent program of muscle atrophy in mice. Commun Biol 2021; 4:703. [PMID: 34103648 PMCID: PMC8187632 DOI: 10.1038/s42003-021-02204-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 05/12/2021] [Indexed: 12/13/2022] Open
Abstract
Random errors in protein synthesis are prevalent and ubiquitous, yet their effect on organismal health has remained enigmatic for over five decades. Here, we studied whether mice carrying the ribosomal ambiguity (ram) mutation Rps2-A226Y, recently shown to increase the inborn error rate of mammalian translation, if at all viable, present any specific, possibly aging-related, phenotype. We introduced Rps2-A226Y using a Cre/loxP strategy. Resulting transgenic mice were mosaic and showed a muscle-related phenotype with reduced grip strength. Analysis of gene expression in skeletal muscle using RNA-Seq revealed transcriptomic changes occurring in an age-dependent manner, involving an interplay of PGC1α, FOXO3, mTOR, and glucocorticoids as key signaling pathways, and finally resulting in activation of a muscle atrophy program. Our results highlight the relevance of translation accuracy, and show how disturbances thereof may contribute to age-related pathologies. By introducing a ribosomal ambiguity mutation into mice, Moore et al. establish an in-vivo model to investigate how age-related diseases are related to decreasing accuracy in protein synthesis. Their findings potentially offer new insights into the pathological changes observed in age-related diseases, such as muscle atrophy
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9
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Joseph J, Doles JD. Disease-associated metabolic alterations that impact satellite cells and muscle regeneration: perspectives and therapeutic outlook. Nutr Metab (Lond) 2021; 18:33. [PMID: 33766031 PMCID: PMC7992337 DOI: 10.1186/s12986-021-00565-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 03/15/2021] [Indexed: 11/10/2022] Open
Abstract
Many chronic disease patients experience a concurrent loss of lean muscle mass. Skeletal muscle is a dynamic tissue maintained by continuous protein turnover and progenitor cell activity. Muscle stem cells, or satellite cells, differentiate (by a process called myogenesis) and fuse to repair and regenerate muscle. During myogenesis, satellite cells undergo extensive metabolic alterations; therefore, pathologies characterized by metabolic derangements have the potential to impair myogenesis, and consequently exacerbate skeletal muscle wasting. How disease-associated metabolic disruptions in satellite cells might be contributing to wasting is an important question that is largely neglected. With this review we highlight the impact of various metabolic disruptions in disease on myogenesis and skeletal muscle regeneration. We also discuss metabolic therapies with the potential to improve myogenesis, skeletal muscle regeneration, and ultimately muscle mass.
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Affiliation(s)
- Josiane Joseph
- Mayo Clinic Medical Scientist Training Program, Mayo Clinic, Rochester, MN, USA
| | - Jason D Doles
- Department of Biochemistry and Molecular Biology, Mayo Clinic, 200 First St SW, Rochester, MN, 55905, USA.
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10
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Xia Q, Huang X, Huang J, Zheng Y, March ME, Li J, Wei Y. The Role of Autophagy in Skeletal Muscle Diseases. Front Physiol 2021; 12:638983. [PMID: 33841177 PMCID: PMC8027491 DOI: 10.3389/fphys.2021.638983] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 02/22/2021] [Indexed: 12/13/2022] Open
Abstract
Skeletal muscle is the most abundant type of tissue in human body, being involved in diverse activities and maintaining a finely tuned metabolic balance. Autophagy, characterized by the autophagosome–lysosome system with the involvement of evolutionarily conserved autophagy-related genes, is an important catabolic process and plays an essential role in energy generation and consumption, as well as substance turnover processes in skeletal muscles. Autophagy in skeletal muscles is finely tuned under the tight regulation of diverse signaling pathways, and the autophagy pathway has cross-talk with other pathways to form feedback loops under physiological conditions and metabolic stress. Altered autophagy activity characterized by either increased formation of autophagosomes or inhibition of lysosome-autophagosome fusion can lead to pathological cascades, and mutations in autophagy genes and deregulation of autophagy pathways have been identified as one of the major causes for a variety of skeleton muscle disorders. The advancement of multi-omics techniques enables further understanding of the molecular and biochemical mechanisms underlying the role of autophagy in skeletal muscle disorders, which may yield novel therapeutic targets for these disorders.
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Affiliation(s)
- Qianghua Xia
- Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou, China
| | - Xubo Huang
- Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou, China
| | - Jieru Huang
- Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou, China
| | - Yongfeng Zheng
- Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou, China
| | - Michael E March
- Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Jin Li
- Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou, China
| | - Yongjie Wei
- Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou, China
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11
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Chung SW, Kim JY, Yoon JP, Suh DW, Yeo WJ, Lee YS. Atrogin1-induced loss of aquaporin 4 in myocytes leads to skeletal muscle atrophy. Sci Rep 2020; 10:14189. [PMID: 32843684 PMCID: PMC7447774 DOI: 10.1038/s41598-020-71167-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 08/10/2020] [Indexed: 12/25/2022] Open
Abstract
The water channel aquaporin 4 (AQP4) regulates the flux of water across the cell membrane, maintaining cellular homeostasis. Since AQP4 is enriched in the sarcolemma of skeletal muscle, a functional defect in AQP4 may cause skeletal muscle dysfunction. To investigate a novel mechanism underlying skeletal muscle atrophy, we examined AQP4 expression and its regulation in muscle using the rotator cuff tear (RCT) model. Human and mouse AQP4 expression was significantly decreased in atrophied muscle resulting from RCT. The size and the number of myotubes were reduced following AQP4 knockdown. Atrogin 1-mediated ubiquitination of AQP4 was verified with an ubiquitination assay after immunoprecipitation of AQP4 with an anti-AQP4 antibody. In this study, we identified high mobility group box 1 (HMGB1) as a potent upstream regulator of atrogin 1 expression. Atrogin 1 expression was increased by recombinant mouse HMGB1 protein, and the HMGB1-induced atrogin 1 expression was mediated via NF-κB signaling. Our study suggests that loss of AQP4 appears to be involved in myocyte shrinkage after RCT, and its degradation is mediated by atrogin 1-dependent ubiquitination. HMGB1, in its function as a signaling molecule upstream of the ubiquitin ligase atrogin 1, was found to be a novel regulator of muscle atrophy.
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Affiliation(s)
- Seok Won Chung
- Department of Orthopedic Surgery, Research Institute of Medical Science, Konkuk University School of Medicine, Seoul, Republic of Korea
| | - Ja-Yeon Kim
- Department of Orthopedic Surgery, Research Institute of Medical Science, Konkuk University School of Medicine, Seoul, Republic of Korea
| | - Jong Pil Yoon
- Department of Orthopedic Surgery, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Dong Won Suh
- Joint Center, Barunsesang Hospital, #75-5, Yatap-ro, Seongnam-si, Gyeonggi-do, 13497, Republic of Korea
| | - Woo Jin Yeo
- Joint Center, Barunsesang Hospital, #75-5, Yatap-ro, Seongnam-si, Gyeonggi-do, 13497, Republic of Korea
| | - Yong-Soo Lee
- Department of Orthopedic Surgery, Research Institute of Medical Science, Konkuk University School of Medicine, Seoul, Republic of Korea. .,Joint Center, Barunsesang Hospital, #75-5, Yatap-ro, Seongnam-si, Gyeonggi-do, 13497, Republic of Korea.
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12
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Potential Cardiovascular and Metabolic Beneficial Effects of ω-3 PUFA in Male Obesity Secondary Hypogonadism Syndrome. Nutrients 2020; 12:nu12092519. [PMID: 32825328 PMCID: PMC7551945 DOI: 10.3390/nu12092519] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/10/2020] [Accepted: 08/17/2020] [Indexed: 02/06/2023] Open
Abstract
Long-chain ω-3 polyunsaturated fatty acids (PUFAs) are fundamental biocomponents of lipids and cell membranes. They are involved in the maintenance of cellular homeostasis and they are able to exert anti-inflammatory and cardioprotective actions. Thanks to their potential beneficial effects on the cardiovascular system, metabolic axis and body composition, we have examined their action in subjects affected by male obesity secondary hypogonadism (MOSH) syndrome. MOSH syndrome is characterized by the presence of obesity associated with the alteration of sexual and metabolic functions. Therefore, this review article aims to analyze scientific literature regarding the possible benefits of ω-3 PUFA administration in subjects affected by MOSH syndrome. We conclude that there are strong evidences supporting ω-3 PUFA administration and/or supplementation for the treatment and management of MOSH patients.
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13
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Tuntevski K, Hajira A, Nichols A, Alway SE, Mohamed JS. Muscle-specific sirtuin1 gain-of-function ameliorates skeletal muscle atrophy in a pre-clinical mouse model of cerebral ischemic stroke. FASEB Bioadv 2020; 2:387-397. [PMID: 32676579 PMCID: PMC7354693 DOI: 10.1096/fba.2020-00017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 04/03/2020] [Accepted: 05/14/2020] [Indexed: 02/07/2023] Open
Abstract
Stroke causes severe long-term disability in patients due to the induction of skeletal muscle atrophy and weakness, but the molecular mechanisms remain elusive. Using a preclinical mouse model of cerebral ischemic stroke, we show that stroke robustly induced atrophy and significantly decreased SirT1 gene expression in the PTA (paralytic tibialis anterior) muscle. Muscle-specific SirT1 gain-of-function mice are resistant to stroke-induced muscle atrophy and this protective effect requires its deacetylase activity. Although SirT1 counteracts the stroke-induced up-regulation of atrogin1, MuRF1 and ZNF216 genes, we found a mechanism that regulates the ZNF216 gene transcription in post-stroke muscle. Stroke increased the expression of the ZNF216 gene in PTA muscle by activating PARP-1, which binds on the ZNF216 promoter. The SirT1 gain-of-function or SirT1 activator, resveratrol, reversed the PARP-1-mediated up-regulation of ZNF216 expression at the promoter level, suggesting a contradicted role for SirT1 and PARP-1 in the regulation of ZNF216 gene. Overall, our study for the first-time demonstrated that (a) stroke causes muscle atrophy, in part, through the SirT1/PARP-1/ZNF216 signaling mechanism; (b) SirT1 can block muscle atrophy in response to different types of atrophic signals via different signaling mechanisms; and (c) SirT1 is a critical regulator of post-stroke muscle mass.
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Affiliation(s)
- Kiril Tuntevski
- Department of Human PerformanceWest Virginia University School of MedicineMorgantownWVUSA
| | - Ameena Hajira
- Department of Human PerformanceWest Virginia University School of MedicineMorgantownWVUSA
| | - Austin Nichols
- Department of Human PerformanceWest Virginia University School of MedicineMorgantownWVUSA
| | - Stephen E. Alway
- Department of Human PerformanceWest Virginia University School of MedicineMorgantownWVUSA
- Laboratory of Muscle Biology and SarcopeniaDepartment of Physical TherapyCollege of Health ProfessionsUniversity of Tennessee Health Science CenterMemphisTNUSA
- Center for Muscle, Metabolism and NeuropathologyDivision of Rehabilitation SciencesCollege of Health ProfessionsUniversity of Tennessee Health Science CenterMemphisTNUSA
| | - Junaith S. Mohamed
- Department of Human PerformanceWest Virginia University School of MedicineMorgantownWVUSA
- Laboratory of Muscle and NerveDepartment of Diagnostic and Health SciencesCollege of Health ProfessionsUniversity of Tennessee Health Science CenterMemphisTNUSA
- Center for Muscle, Metabolism and NeuropathologyDivision of Rehabilitation SciencesCollege of Health ProfessionsUniversity of Tennessee Health Science CenterMemphisTNUSA
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14
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Preventive Effects of Schisandrin A, A Bioactive Component of Schisandra chinensis, on Dexamethasone-Induced Muscle Atrophy. Nutrients 2020; 12:nu12051255. [PMID: 32354126 PMCID: PMC7282012 DOI: 10.3390/nu12051255] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 04/24/2020] [Accepted: 04/25/2020] [Indexed: 12/11/2022] Open
Abstract
Muscle wasting is caused by various factors, such as aging, cancer, diabetes, and chronic kidney disease, and significantly decreases the quality of life. However, therapeutic interventions for muscle atrophy have not yet been well-developed. In this study, we investigated the effects of schisandrin A (SNA), a component extracted from the fruits of Schisandra chinensis, on dexamethasone (DEX)-induced muscle atrophy in mice and studied the underlying mechanisms. DEX+SNA-treated mice had significantly increased grip strength, muscle weight, and muscle fiber size compared with DEX+vehicle-treated mice. In addition, SNA treatment significantly reduced the expression of muscle degradation factors such as myostatin, MAFbx (atrogin1), and muscle RING-finger protein-1 (MuRF1) and enhanced the expression of myosin heavy chain (MyHC) compared to the vehicle. In vitro studies using differentiated C2C12 myotubes also showed that SNA treatment decreased the expression of muscle degradation factors induced by dexamethasone and increased protein synthesis and expression of MyHCs by regulation of Akt/FoxO and Akt/70S6K pathways, respectively. These results suggest that SNA reduces protein degradation and increases protein synthesis in the muscle, contributing to the amelioration of dexamethasone-induced muscle atrophy and may be a potential candidate for the prevention and treatment of muscle atrophy.
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15
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Nakao R, Abe T, Yamamoto S, Oishi K. Ketogenic diet induces skeletal muscle atrophy via reducing muscle protein synthesis and possibly activating proteolysis in mice. Sci Rep 2019; 9:19652. [PMID: 31873138 PMCID: PMC6928149 DOI: 10.1038/s41598-019-56166-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 12/05/2019] [Indexed: 12/27/2022] Open
Abstract
Ketogenic diets (KD) that are very high in fat and low in carbohydrates are thought to simulate the metabolic effects of starvation. We fed mice with a KD for seven days to assess the underlying mechanisms of muscle wasting induced by chronic starvation. This diet decreased the weight of the gastrocnemius (Ga), tibialis anterior (TA) and soleus (Sol) muscles by 23%, 11% and 16%, respectively. The size of Ga, TA, Sol muscle fibers and the grip strength of four limbs also significantly declined by 20%, 28%, 16% and 22%, respectively. The muscle atrophy-related genes Mafbx, Murf1, Foxo3, Lc3b and Klf15 were upregulated in the skeletal muscles of mice fed with the KD. In accordance with the reduced expression of anabolic genes such as Igf1, surface sensing of translation (SUnSET) analyses of fast-twitch Ga, TA and Sol muscles revealed that the KD suppressed muscle protein synthesis. The mRNA expression of oxidative stress-responsive genes such as Sod1 was significantly increased in all muscles examined. In addition to hypercorticosteronemia, hypoinsulinemia and reduced IGF-1, oxidative stress might also be involved in KD-induced muscle atrophy. Feeding mice with a KD is a novel experimental animal model of muscle-wasting induced by chronic starvation.
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Affiliation(s)
- Reiko Nakao
- Biological Clock Research Group, Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8566, Japan
| | - Tomoki Abe
- Biological Clock Research Group, Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8566, Japan
| | - Saori Yamamoto
- Biological Clock Research Group, Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8566, Japan
| | - Katsutaka Oishi
- Biological Clock Research Group, Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8566, Japan. .,Department of Applied Biological Science, Graduate School of Science and Technology, Tokyo University of Science, Noda, Chiba, 278-8510, Japan. .,Department of Computational and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, 277-0882, Japan. .,School of Integrative and Global Majors (SIGMA), University of Tsukuba, Tsukuba, Ibaraki, 305-8577, Japan.
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16
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Powers SK, Morton AB, Hyatt H, Hinkley MJ. The Renin-Angiotensin System and Skeletal Muscle. Exerc Sport Sci Rev 2018; 46:205-214. [PMID: 30001274 DOI: 10.1249/jes.0000000000000158] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The renin-angiotensin system (RAS) plays a key role in the control of blood pressure and fluid homeostasis. Emerging evidence also reveals that hyperactivity of the RAS contributes to skeletal muscle wasting. This review discusses the key role that the RAS plays in skeletal muscle wasting due to congestive heart failure, chronic kidney disease, and ventilator-induced diaphragmatic wasting.
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Affiliation(s)
- Scott K Powers
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL
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17
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Abstract
The cancer anorexia cachexia syndrome is a systemic metabolic disorder characterized by the catabolism of stored nutrients in skeletal muscle and adipose tissue that is particularly prevalent in nonsmall cell lung cancer (NSCLC). Loss of skeletal muscle results in functional impairments and increased mortality. The aim of the present study was to characterize the changes in systemic metabolism in a genetically engineered mouse model of NSCLC. We show that a portion of these animals develop loss of skeletal muscle, loss of adipose tissue, and increased inflammatory markers mirroring the human cachexia syndrome. Using noncachexic and fasted animals as controls, we report a unique cachexia metabolite phenotype that includes the loss of peroxisome proliferator-activated receptor-α (PPARα) -dependent ketone production by the liver. In this setting, glucocorticoid levels rise and correlate with skeletal muscle degradation and hepatic markers of gluconeogenesis. Restoring ketone production using the PPARα agonist, fenofibrate, prevents the loss of skeletal muscle mass and body weight. These results demonstrate how targeting hepatic metabolism can prevent muscle wasting in lung cancer, and provide evidence for a therapeutic strategy.
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18
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Whiteman JP, Harlow HJ, Durner GM, Regehr EV, Rourke BC, Robles M, Amstrup SC, Ben-David M. Polar bears experience skeletal muscle atrophy in response to food deprivation and reduced activity in winter and summer. CONSERVATION PHYSIOLOGY 2017; 5:cox049. [PMID: 28835844 PMCID: PMC5550809 DOI: 10.1093/conphys/cox049] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 07/05/2017] [Accepted: 07/26/2017] [Indexed: 05/31/2023]
Abstract
When reducing activity and using stored energy during seasonal food shortages, animals risk degradation of skeletal muscles, although some species avoid or minimize the resulting atrophy while experiencing these conditions during hibernation. Polar bears may be food deprived and relatively inactive during winter (when pregnant females hibernate and hunting success declines for other demographic groups) as well as summer (when sea ice retreats from key foraging habitats). We investigated muscle atrophy in samples of biceps femoris collected from free-ranging polar bears in the Southern Beaufort Sea (SBS) throughout their annual cycle. Atrophy was most pronounced in April-May as a result of food deprivation during the previous winter, with muscles exhibiting reduced protein concentration, increased water content, and lower creatine kinase mRNA. These animals increased feeding and activity in spring (when seal prey becomes more available), initiating a period of muscle recovery. During the following ice melt of late summer, ~30% of SBS bears abandon retreating sea ice for land; in August, these 'shore' bears exhibited no muscle atrophy, indicating that they had fully recovered from winter food deprivation. These individuals subsequently scavenged whale carcasses deposited by humans and by October, had retained good muscle condition. In contrast, ~70% of SBS bears follow the ice north in late summer, into deep water with less prey. These 'ice' bears fast; by October, they exhibited muscle protein loss and rapid changes in myosin heavy-chain isoforms in response to reduced activity. These findings indicate that, unlike other bears during winter hibernation, polar bears without food in summer cannot mitigate atrophy. Consequently, prolonged summer fasting resulting from climate change-induced ice loss creates a risk of greater muscle atrophy and reduced abilities to travel and hunt.
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Affiliation(s)
- John P. Whiteman
- Program in Ecology, University of Wyoming, 1000 E. University Avenue, Laramie, WY 82071, USA
- Department of Zoology and Physiology, University of Wyoming, 1000 E. University Avenue, Laramie, WY 82071, USA
| | - Henry J. Harlow
- Department of Zoology and Physiology, University of Wyoming, 1000 E. University Avenue, Laramie, WY 82071, USA
| | - George M. Durner
- U.S. Geological Survey, Alaska Science Center, 4210 University Drive, Anchorage, AK 99508, USA
| | - Eric V. Regehr
- Marine Mammals Management, U.S. Fish and Wildlife Service, 1011 East Tudor Road, Anchorage, AK 99503, USA
- Current: Polar Science Center, Applied Physics Laboratory, University of Washington, 1013 NE 40th Street, Seattle, WA 98105, USA
| | - Bryan C. Rourke
- Department of Biological Sciences, California State University, 1250 Bellflower Blvd, Long Beach, CA 90840, USA
| | - Manuel Robles
- Department of Biological Sciences, California State University, 1250 Bellflower Blvd, Long Beach, CA 90840, USA
| | | | - Merav Ben-David
- Program in Ecology, University of Wyoming, 1000 E. University Avenue, Laramie, WY 82071, USA
- Department of Zoology and Physiology, University of Wyoming, 1000 E. University Avenue, Laramie, WY 82071, USA
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19
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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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20
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Tsuchida W, Iwata M, Akimoto T, Matsuo S, Asai Y, Suzuki S. Heat Stress Modulates Both Anabolic and Catabolic Signaling Pathways Preventing Dexamethasone-Induced Muscle Atrophy In Vitro. J Cell Physiol 2017; 232:650-664. [PMID: 27649272 PMCID: PMC5132157 DOI: 10.1002/jcp.25609] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Accepted: 09/19/2016] [Indexed: 12/29/2022]
Abstract
It is generally recognized that synthetic glucocorticoids induce skeletal muscle weakness, and endogenous glucocorticoid levels increase in patients with muscle atrophy. It is reported that heat stress attenuates glucocorticoid-induced muscle atrophy; however, the mechanisms involved are unknown. Therefore, we examined the mechanisms underlying the effects of heat stress against glucocorticoid-induced muscle atrophy using C2C12 myotubes in vitro, focusing on expression of key molecules and signaling pathways involved in regulating protein synthesis and degradation. The synthetic glucocorticoid dexamethasone decreased myotube diameter and protein content, and heat stress prevented the morphological and biochemical glucocorticoid effects. Heat stress also attenuated increases in mRNAs of regulated in development and DNA damage responses 1 (REDD1) and Kruppel-like factor 15 (KLF15). Heat stress recovered the dexamethasone-induced inhibition of PI3K/Akt signaling. These data suggest that changes in anabolic and catabolic signals are involved in heat stress-induced protection against glucocorticoid-induced muscle atrophy. These results have a potentially broad clinical impact because elevated glucocorticoid levels are implicated in a wide range of diseases associated with muscle wasting. J. Cell. Physiol. 232: 650-664, 2017. © 2016 The Authors. Journal of Cellular Physiology published by Wiley Periodicals, Inc.
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Affiliation(s)
- Wakako Tsuchida
- Department of RehabilitationFaculty of Health SciencesNihon Fukushi UniversityHandaAichiJapan
- Program in Physical and Occupational TherapyGraduate School of MedicineNagoya UniversityNagoyaAichiJapan
| | - Masahiro Iwata
- Department of RehabilitationFaculty of Health SciencesNihon Fukushi UniversityHandaAichiJapan
- Program in Physical and Occupational TherapyGraduate School of MedicineNagoya UniversityNagoyaAichiJapan
| | - Takayuki Akimoto
- Faculty of Sport SciencesWaseda UniversityTokorozawaSaitamaJapan
| | - Shingo Matsuo
- Department of RehabilitationFaculty of Health SciencesNihon Fukushi UniversityHandaAichiJapan
- Program in Physical and Occupational TherapyGraduate School of MedicineNagoya UniversityNagoyaAichiJapan
| | - Yuji Asai
- Department of RehabilitationFaculty of Health SciencesNihon Fukushi UniversityHandaAichiJapan
| | - Shigeyuki Suzuki
- Program in Physical and Occupational TherapyGraduate School of MedicineNagoya UniversityNagoyaAichiJapan
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21
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Abstract
Cachexia represents progressive wasting of muscle and adipose tissue and is associated with increased morbidity and mortality. Although anorexia usually accompanies cachexia, cachexia rarely responds to increased food intake alone. Our knowledge of the underlying mechanisms responsible for cachexia remains incomplete. However, most states of cachexia are associated with underlying inflammatory processes and/or cancer. These processes activate protein degradation and lipolytic pathways, resulting in tissue loss. In this article, we briefly review the pathophysiology of cachexia and discuss the role of specific nutrient supplements for the treatment of cachexia. The branched chain amino acid leucine, the leucine metabolite beta-hydroxy-beta-methylbutyrate, arginine, glutamine, omega-3 long chain fatty acids, conjugated linoleic acid, and polyphenols have demonstrated some efficacy in animal and/or human studies. Optimal treatment for cachexia is likely aimed at maximizing muscle and adipose synthesis while minimizing degradation.
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Affiliation(s)
- Rafat Siddiqui
- Methodist Research Institute, 1812 N Capitol Ave, Wile Hall, Room 120, Indianapolis, IN 46202, USA
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22
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Przygodda F, Manfredi LH, Machado J, Gonçalves DAP, Zanon NM, Bonagamba LGH, Machado BH, Kettelhut ÍC, Navegantes LCC. Acute intermittent hypoxia in rats activates muscle proteolytic pathways through a gluccorticoid-dependent mechanism. J Appl Physiol (1985) 2016; 122:1114-1124. [PMID: 27932681 DOI: 10.1152/japplphysiol.00977.2015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 11/18/2016] [Accepted: 12/03/2016] [Indexed: 02/08/2023] Open
Abstract
Although it is well known that chronic hypoxia induces muscle wasting, the effects of intermittent hypoxia on skeletal muscle protein metabolism remain unclear. We hypothesized that acute intermittent hypoxia (AIH), a challenge that activates the hypothalamic-pituitary-adrenal axis, would alter muscle protein homeostasis through a glucocorticoid-dependent mechanism. Three-week-old rats were submitted to adrenalectomy (ADX) and exposed to 8 h of AIH (6% O2 for 40 s at 9-min intervals). Animals were euthanized, and the soleus and extensor digitorum longus (EDL) muscles were harvested and incubated in vitro for measurements of protein turnover. AIH increased plasma levels of corticosterone and induced insulin resistance as estimated by the insulin tolerance test and lower rates of muscle glucose oxidation and the HOMA index. In both soleus and EDL muscles, rates of overall proteolysis increased after AIH. This rise was accompanied by an increased proteolytic activities of the ubiquitin(Ub)-proteasome system (UPS) and lysosomal and Ca2+-dependent pathways. Furthermore, AIH increased Ub-protein conjugates and gene expression of atrogin-1 and MuRF-1, two key Ub-protein ligases involved in muscle atrophy. In parallel, AIH increased the mRNA expression of the autophagy-related genes LC3b and GABARAPl1. In vitro rates of protein synthesis in skeletal muscles did not differ between AIH and control rats. ADX completely blocked the insulin resistance in hypoxic rats and the AIH-induced activation of proteolytic pathways and atrogene expression in both soleus and EDL muscles. These results demonstrate that AIH induces insulin resistance in association with activation of the UPS, the autophagic-lysosomal process, and Ca2+-dependent proteolysis through a glucocorticoid-dependent mechanism.NEW & NOTEWORTHY Since hypoxia is a condition in which the body is deprived of adequate oxygen supply and muscle wasting is induced, the present work provides evidence linking hypoxia to proteolysis through a glucocorticoid-dependent mechanism. We show that the activation of proteolytic pathways, atrophy-related genes, and insulin resistance in rats exposed to acute intermittent hypoxia was abolished by surgical removal of adrenal gland. This finding will be helpful for understanding of the muscle wasting in hypoxemic conditions.
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Affiliation(s)
- Franciele Przygodda
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Leandro Henrique Manfredi
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.,Federal University of Fronteira Sul, Chapecó, Santa Catarina, Brazil
| | - Juliano Machado
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Dawit A P Gonçalves
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.,Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil; and
| | - Neusa M Zanon
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Leni G H Bonagamba
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Benedito H Machado
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Ísis C Kettelhut
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.,Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil; and
| | - Luiz C C Navegantes
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil;
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23
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Abstract
Metabolic dysfunction contributes to the clinical deterioration observed in advanced cancer patients and is characterized by weight loss, skeletal muscle wasting, and atrophy of the adipose tissue. This systemic syndrome, termed cancer-associated cachexia (CAC), is a major cause of morbidity and mortality. While once attributed solely to decreased food intake, the present description of cancer cachexia is a disorder of multiorgan energy imbalance. Here we review the molecules and pathways responsible for metabolic dysfunction in CAC and the ideas that led to the current understanding.
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Affiliation(s)
- Michele Petruzzelli
- Department of Oncology, The Medical Research Council Cancer Unit, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, United Kingdon
| | - Erwin F Wagner
- Genes, Development, and Disease Group, Cancer Cell Biology Programme, Centro Nacional de Investigaciones Oncológicas, Madrid 28029, Spain
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24
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Morgan SA, Hassan-Smith ZK, Doig CL, Sherlock M, Stewart PM, Lavery GG. Glucocorticoids and 11β-HSD1 are major regulators of intramyocellular protein metabolism. J Endocrinol 2016; 229:277-86. [PMID: 27048233 PMCID: PMC5064767 DOI: 10.1530/joe-16-0011] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 04/05/2016] [Indexed: 11/08/2022]
Abstract
The adverse metabolic effects of prescribed and endogenous glucocorticoid excess, 'Cushing's syndrome', create a significant health burden. While skeletal muscle atrophy and resultant myopathy is a clinical feature, the molecular mechanisms underpinning these changes are not fully defined. We have characterized the impact of glucocorticoids upon key metabolic pathways and processes regulating muscle size and mass including: protein synthesis, protein degradation, and myoblast proliferation in both murine C2C12 and human primary myotube cultures. Furthermore, we have investigated the role of pre-receptor modulation of glucocorticoid availability by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) in these processes. Corticosterone (CORT) decreased myotube area, decreased protein synthesis, and increased protein degradation in murine myotubes. This was supported by decreased mRNA expression of insulin-like growth factor (IGF1), decreased activating phosphorylation of mammalian target of rapamycin (mTOR), decreased phosphorylation of 4E binding protein 1 (4E-BP1), and increased mRNA expression of key atrophy markers including: atrogin-1, forkhead box O3a (FOXO3a), myostatin (MSTN), and muscle-ring finger protein-1 (MuRF1). These findings were endorsed in human primary myotubes, where cortisol also decreased protein synthesis and increased protein degradation. The effects of 11-dehydrocorticosterone (11DHC) (in murine myotubes) and cortisone (in human myotubes) on protein metabolism were indistinguishable from that of CORT/cortisol treatments. Selective 11β-HSD1 inhibition blocked the decrease in protein synthesis, increase in protein degradation, and reduction in myotube area induced by 11DHC/cortisone. Furthermore, CORT/cortisol, but not 11DHC/cortisone, decreased murine and human myoblast proliferative capacity. Glucocorticoids are potent regulators of skeletal muscle protein homeostasis and myoblast proliferation. Our data underscores the potential use of selective 11β-HSD1 inhibitors to ameliorate muscle-wasting effects associated with glucocorticoid excess.
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Affiliation(s)
- Stuart A Morgan
- Institute of Metabolism and Systems ResearchInstitute of Biomedical Research, University of Birmingham, Birmingham, UK Centre for Endocrinology Diabetes and MetabolismBirmingham Health Partners, University of Birmingham, Birmingham, UK
| | - Zaki K Hassan-Smith
- Institute of Metabolism and Systems ResearchInstitute of Biomedical Research, University of Birmingham, Birmingham, UK Centre for Endocrinology Diabetes and MetabolismBirmingham Health Partners, University of Birmingham, Birmingham, UK
| | - Craig L Doig
- Institute of Metabolism and Systems ResearchInstitute of Biomedical Research, University of Birmingham, Birmingham, UK Centre for Endocrinology Diabetes and MetabolismBirmingham Health Partners, University of Birmingham, Birmingham, UK
| | - Mark Sherlock
- Institute of Metabolism and Systems ResearchInstitute of Biomedical Research, University of Birmingham, Birmingham, UK Centre for Endocrinology Diabetes and MetabolismBirmingham Health Partners, University of Birmingham, Birmingham, UK
| | - Paul M Stewart
- Institute of Metabolism and Systems ResearchInstitute of Biomedical Research, University of Birmingham, Birmingham, UK Centre for Endocrinology Diabetes and MetabolismBirmingham Health Partners, University of Birmingham, Birmingham, UK School of MedicineWorsley Building, University of Leeds, Leeds, UK
| | - Gareth G Lavery
- Institute of Metabolism and Systems ResearchInstitute of Biomedical Research, University of Birmingham, Birmingham, UK Centre for Endocrinology Diabetes and MetabolismBirmingham Health Partners, University of Birmingham, Birmingham, UK
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25
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Hochberg I, Harvey I, Tran QT, Stephenson EJ, Barkan AL, Saltiel AR, Chandler WF, Bridges D. Gene expression changes in subcutaneous adipose tissue due to Cushing's disease. J Mol Endocrinol 2015; 55:81-94. [PMID: 26150553 PMCID: PMC4543687 DOI: 10.1530/jme-15-0119] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/06/2015] [Indexed: 01/15/2023]
Abstract
Glucocorticoids have major effects on adipose tissue metabolism. To study tissue mRNA expression changes induced by chronic elevated endogenous glucocorticoids, we performed RNA sequencing on the subcutaneous adipose tissue from patients with Cushing's disease (n=5) compared to patients with nonfunctioning pituitary adenomas (n=11). We found a higher expression of transcripts involved in several metabolic pathways, including lipogenesis, proteolysis and glucose oxidation as well as a decreased expression of transcripts involved in inflammation and protein synthesis. To further study this in a model system, we subjected mice to dexamethasone treatment for 12 weeks and analyzed their inguinal (subcutaneous) fat pads, which led to similar findings. Additionally, mice treated with dexamethasone showed drastic decreases in lean body mass as well as increased fat mass, further supporting the human transcriptomic data. These data provide insight to transcriptional changes that may be responsible for the comorbidities associated with chronic elevations of glucocorticoids.
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Affiliation(s)
- Irit Hochberg
- Institute of EndocrinologyDiabetes and Metabolism, Rambam Health Care Campus, Haifa, IsraelLife Science InstituteUniversity of Michigan, Ann Arbor, MI, USAPhysiologyUTHSC, Memphis, TN, USAPreventive MedicineUTHSC, Memphis, TN, USAInternal MedicineUniversity of Michigan, Ann Arbor, MI USANeurosurgeryUniversity of Michigan, Ann Arbor, MI USAPediatricsUTHSC, Memphis, TN, USA Institute of EndocrinologyDiabetes and Metabolism, Rambam Health Care Campus, Haifa, IsraelLife Science InstituteUniversity of Michigan, Ann Arbor, MI, USAPhysiologyUTHSC, Memphis, TN, USAPreventive MedicineUTHSC, Memphis, TN, USAInternal MedicineUniversity of Michigan, Ann Arbor, MI USANeurosurgeryUniversity of Michigan, Ann Arbor, MI USAPediatricsUTHSC, Memphis, TN, USA
| | - Innocence Harvey
- Institute of EndocrinologyDiabetes and Metabolism, Rambam Health Care Campus, Haifa, IsraelLife Science InstituteUniversity of Michigan, Ann Arbor, MI, USAPhysiologyUTHSC, Memphis, TN, USAPreventive MedicineUTHSC, Memphis, TN, USAInternal MedicineUniversity of Michigan, Ann Arbor, MI USANeurosurgeryUniversity of Michigan, Ann Arbor, MI USAPediatricsUTHSC, Memphis, TN, USA
| | - Quynh T Tran
- Institute of EndocrinologyDiabetes and Metabolism, Rambam Health Care Campus, Haifa, IsraelLife Science InstituteUniversity of Michigan, Ann Arbor, MI, USAPhysiologyUTHSC, Memphis, TN, USAPreventive MedicineUTHSC, Memphis, TN, USAInternal MedicineUniversity of Michigan, Ann Arbor, MI USANeurosurgeryUniversity of Michigan, Ann Arbor, MI USAPediatricsUTHSC, Memphis, TN, USA
| | - Erin J Stephenson
- Institute of EndocrinologyDiabetes and Metabolism, Rambam Health Care Campus, Haifa, IsraelLife Science InstituteUniversity of Michigan, Ann Arbor, MI, USAPhysiologyUTHSC, Memphis, TN, USAPreventive MedicineUTHSC, Memphis, TN, USAInternal MedicineUniversity of Michigan, Ann Arbor, MI USANeurosurgeryUniversity of Michigan, Ann Arbor, MI USAPediatricsUTHSC, Memphis, TN, USA
| | - Ariel L Barkan
- Institute of EndocrinologyDiabetes and Metabolism, Rambam Health Care Campus, Haifa, IsraelLife Science InstituteUniversity of Michigan, Ann Arbor, MI, USAPhysiologyUTHSC, Memphis, TN, USAPreventive MedicineUTHSC, Memphis, TN, USAInternal MedicineUniversity of Michigan, Ann Arbor, MI USANeurosurgeryUniversity of Michigan, Ann Arbor, MI USAPediatricsUTHSC, Memphis, TN, USA
| | - Alan R Saltiel
- Institute of EndocrinologyDiabetes and Metabolism, Rambam Health Care Campus, Haifa, IsraelLife Science InstituteUniversity of Michigan, Ann Arbor, MI, USAPhysiologyUTHSC, Memphis, TN, USAPreventive MedicineUTHSC, Memphis, TN, USAInternal MedicineUniversity of Michigan, Ann Arbor, MI USANeurosurgeryUniversity of Michigan, Ann Arbor, MI USAPediatricsUTHSC, Memphis, TN, USA
| | - William F Chandler
- Institute of EndocrinologyDiabetes and Metabolism, Rambam Health Care Campus, Haifa, IsraelLife Science InstituteUniversity of Michigan, Ann Arbor, MI, USAPhysiologyUTHSC, Memphis, TN, USAPreventive MedicineUTHSC, Memphis, TN, USAInternal MedicineUniversity of Michigan, Ann Arbor, MI USANeurosurgeryUniversity of Michigan, Ann Arbor, MI USAPediatricsUTHSC, Memphis, TN, USA
| | - Dave Bridges
- Institute of EndocrinologyDiabetes and Metabolism, Rambam Health Care Campus, Haifa, IsraelLife Science InstituteUniversity of Michigan, Ann Arbor, MI, USAPhysiologyUTHSC, Memphis, TN, USAPreventive MedicineUTHSC, Memphis, TN, USAInternal MedicineUniversity of Michigan, Ann Arbor, MI USANeurosurgeryUniversity of Michigan, Ann Arbor, MI USAPediatricsUTHSC, Memphis, TN, USA Institute of EndocrinologyDiabetes and Metabolism, Rambam Health Care Campus, Haifa, IsraelLife Science InstituteUniversity of Michigan, Ann Arbor, MI, USAPhysiologyUTHSC, Memphis, TN, USAPreventive MedicineUTHSC, Memphis, TN, USAInternal MedicineUniversity of Michigan, Ann Arbor, MI USANeurosurgeryUniversity of Michigan, Ann Arbor, MI USAPediatricsUTHSC, Memphis, TN, USA Institute of EndocrinologyDiabetes and Metabolism, Rambam Health Care Campus, Haifa, IsraelLife Science InstituteUniversity of Michigan, Ann Arbor, MI, USAPhysiologyUTHSC, Memphis, TN, USAPreventive MedicineUTHSC, Memphis, TN, USAInternal MedicineUniversity of Michigan, Ann Arbor, MI USANeurosurgeryUniversity of Michigan, Ann Arbor, MI USAPediatricsUTHSC, Memphis, TN, USA
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Boncompagni S, Arthurton L, Akujuru E, Pearson T, Steverding D, Protasi F, Mutungi G. Membrane glucocorticoid receptors are localised in the extracellular matrix and signal through the MAPK pathway in mammalian skeletal muscle fibres. J Physiol 2015; 593:2679-92. [PMID: 25846902 DOI: 10.1113/jp270502] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 03/30/2015] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Many studies have previously suggested the existence of stress hormone receptors on the cell membrane of many cell types, including skeletal muscle fibres; however, the exact localisation of these receptors and how they signal to the rest of the cell is poorly understood. In this study, we investigated the localisation and the mechanism(s) underlying the physiological functions of these receptors in mouse skeletal muscle cells. We found that the receptors were present throughout muscle development and that, in adult muscle fibres, they were localised in the extracellular matrix, satellite cells (muscle stem cells) and close to mitochondria. We also found that they signalled to the rest of the cell by activating enzymes called mitogen-activated protein kinases. From these results we suggest that, at physiological concentrations, stress hormones may be important in skeletal muscle differentiation, repair and regeneration. ABSTRACT A number of studies have previously proposed the existence of glucocorticoid receptors on the plasma membrane of many cell types, including skeletal muscle fibres. However, their exact localisation and the cellular signalling pathway(s) they utilise to communicate with the rest of the cell are still poorly understood. In this study, we investigated the localisation and the mechanism(s) underlying the non-genomic physiological functions of these receptors in mouse skeletal muscle cells. The results show that the receptors were localised in the cytoplasm in myoblasts, in the nucleus in myotubes, in the extracellular matrix, in satellite cells and in the proximity of mitochondria in adult muscle fibres. Also, they bound laminin in a glucocorticoid-dependent manner. Treating small skeletal muscle fibre bundles with the synthetic glucocorticoid beclomethasone dipropionate increased the phosphorylation (= activation) of extracellular signal-regulated kinases 1 and 2, c-Jun N-terminal kinase and p38 mitogen-activated protein kinase. This occurred within 5 min and depended on the fibre type and the duration of the treatment. It was also abolished by the glucocorticoid receptor inhibitor, mifepristone, and a monoclonal antibody against the receptor. From these results we conclude that the non-genomic/non-canonical physiological functions of glucocorticoids, in adult skeletal muscle fibres, are mediated by a glucocorticoid receptor localised in the extracellular matrix, in satellite cells and close to mitochondria, and involve activation of the mitogen-activated protein kinase pathway.
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Affiliation(s)
- Simona Boncompagni
- Centre for Research on Aging, University G. d'Annunzio, I-66013, Chieti, Italy
| | - Lewis Arthurton
- School of Life Sciences, University of Liverpool, Liverpool, L69 7ZB, UK
| | - Eugene Akujuru
- Department of Medicine, Norwich Medical School, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Timothy Pearson
- Department of Medicine, Norwich Medical School, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Dietmar Steverding
- Department of Medicine, Norwich Medical School, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Feliciano Protasi
- Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio, I-66013, Chieti, Italy
| | - Gabriel Mutungi
- Department of Medicine, Norwich Medical School, University of East Anglia, Norwich, NR4 7TJ, UK
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Lee SR, Ko TH, Kim HK, Marquez J, Ko KS, Rhee BD, Han J. Influence of starvation on heart contractility and corticosterone level in rats. Pflugers Arch 2015; 467:2351-60. [PMID: 25784619 DOI: 10.1007/s00424-015-1701-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2015] [Revised: 03/04/2015] [Accepted: 03/05/2015] [Indexed: 12/13/2022]
Abstract
The physiological changes, including cardiac modification, that occur during starvation are not yet completely understood. The purpose of this study is to examine the effects of a 2-week starvation period on heart contractility, muscle mass, and irisin and corticosterone levels in rats. Rats in the starved group showed a significant reduction in the body, heart, kidney, and muscle weight (n = 23, p < 0.05). Blood glucose, total protein, and albumin showed a 44, 17.5, and 10.3 % reduction, respectively (p < 0.05). Lipid reserves, such as total lipid, triglyceride, and free fatty acid, were also comparably reduced (p < 0.05). However, the bilirubin, creatinine, blood urea nitrogen, and creatine kinase levels were higher than in the control group (p < 0.05). The blood irisin level was unchanged, but the stress-related corticosterone level was significantly higher in the starved group. The differences observed in M-mode echocardiography were further compared with the body-weight-matched control group. Starvation reduced the left ventricle mass; however, this difference was not significant compared with the body-weight-matched group (p > 0.05). In the starvation group, the impairment of cardiac output was dependent on the reduction in stroke volume and heart rate. Starvation induced a severe reduction in ejection fraction and fractional shortening when compared with the body-weight-matched control group (p < 0.05). In summary, prolonged starvation, which leads to a deficiency of available nutrition, increases the stress-related corticosterone level, impairs the cardiac output, and is associated with changes in cardiac morphogeometry.
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Affiliation(s)
- Sung Ryul Lee
- National Research Laboratory for Mitochondrial Signaling, Department of Physiology, College of Medicine, Cardiovascular and Metabolic Disease Center, Inje University, Bokji-Ro 57, Busanjin-gu, Busan, 614-735, Republic of Korea
| | - Tae Hee Ko
- National Research Laboratory for Mitochondrial Signaling, Department of Physiology, College of Medicine, Cardiovascular and Metabolic Disease Center, Inje University, Bokji-Ro 57, Busanjin-gu, Busan, 614-735, Republic of Korea
| | - Hyoung Kyu Kim
- National Research Laboratory for Mitochondrial Signaling, Department of Physiology, College of Medicine, Cardiovascular and Metabolic Disease Center, Inje University, Bokji-Ro 57, Busanjin-gu, Busan, 614-735, Republic of Korea
| | - Jubert Marquez
- National Research Laboratory for Mitochondrial Signaling, Department of Physiology, College of Medicine, Cardiovascular and Metabolic Disease Center, Inje University, Bokji-Ro 57, Busanjin-gu, Busan, 614-735, Republic of Korea
| | - Kyung Soo Ko
- National Research Laboratory for Mitochondrial Signaling, Department of Physiology, College of Medicine, Cardiovascular and Metabolic Disease Center, Inje University, Bokji-Ro 57, Busanjin-gu, Busan, 614-735, Republic of Korea
| | - Byoung Doo Rhee
- National Research Laboratory for Mitochondrial Signaling, Department of Physiology, College of Medicine, Cardiovascular and Metabolic Disease Center, Inje University, Bokji-Ro 57, Busanjin-gu, Busan, 614-735, Republic of Korea
| | - Jin Han
- National Research Laboratory for Mitochondrial Signaling, Department of Physiology, College of Medicine, Cardiovascular and Metabolic Disease Center, Inje University, Bokji-Ro 57, Busanjin-gu, Busan, 614-735, Republic of Korea.
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Braun TP, Marks DL. The regulation of muscle mass by endogenous glucocorticoids. Front Physiol 2015; 6:12. [PMID: 25691871 PMCID: PMC4315033 DOI: 10.3389/fphys.2015.00012] [Citation(s) in RCA: 155] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 01/08/2015] [Indexed: 01/16/2023] Open
Abstract
Glucocorticoids are highly conserved fundamental regulators of energy homeostasis. In response to stress in the form of perceived danger or acute inflammation, glucocorticoids are released from the adrenal gland, rapidly mobilizing energy from carbohydrate, fat and protein stores. In the case of inflammation, mobilized protein is critical for the rapid synthesis of acute phase reactants and an efficient immune response to infection. While adaptive in response to infection, chronic mobilization can lead to a profound depletion of energy stores. Skeletal muscle represents the major body store of protein, and can become substantially atrophied under conditions of chronic inflammation. Glucocorticoids elicit the atrophy of muscle by increasing the rate of protein degradation by the ubiquitin-proteasome system and autophagy lysosome system. Protein synthesis is also suppressed at the level of translational initiation, preventing the production of new myofibrillar protein. Glucocorticoids also antagonize the action of anabolic regulators such as insulin further exacerbating the loss of protein and muscle mass. The loss of muscle mass in the context of chronic disease is a key feature of cachexia and contributes substantially to morbidity and mortality. A growing body of evidence demonstrates that glucocorticoid signaling is a common mediator of wasting, irrespective of the underlying initiator or disease state. This review will highlight fundamental mechanisms of glucocorticoid signaling and detail the mechanisms of glucocorticoid-induced muscle atrophy. Additionally, the evidence for glucocorticoids as a driver of muscle wasting in numerous disease states will be discussed. Given the burden of wasting diseases and the nodal nature of glucocorticoid signaling, effective anti-glucocorticoid therapy would be a valuable clinical tool. Therefore, the progress and potential pitfalls in the development of glucocorticoid antagonists for muscle wasting will be discussed.
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Affiliation(s)
- Theodore P Braun
- Department of Internal Medicine, University of Washington Medical Center Seattle, WA, USA ; Papé Family Pediatric Research Institute, Oregon Health and Science University Portland, OR, USA
| | - Daniel L Marks
- Department of Internal Medicine, University of Washington Medical Center Seattle, WA, USA
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29
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Abstract
Muscle RING finger 1 (MuRF1) and muscle atrophy F-box (MAFbx)/atrogin-1 were identified more than 10 years ago as two muscle-specific E3 ubiquitin ligases that are increased transcriptionally in skeletal muscle under atrophy-inducing conditions, making them excellent markers of muscle atrophy. In the past 10 years much has been published about MuRF1 and MAFbx with respect to their mRNA expression patterns under atrophy-inducing conditions, their transcriptional regulation, and their putative substrates. However, much remains to be learned about the physiological role of both genes in the regulation of mass and other cellular functions in striated muscle. Although both MuRF1 and MAFbx are enriched in skeletal, cardiac, and smooth muscle, this review will focus on the current understanding of MuRF1 and MAFbx in skeletal muscle, highlighting the critical questions that remain to be answered.
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Affiliation(s)
- Sue C Bodine
- Departments of Neurobiology, Physiology, and Behavior and Physiology and Membrane Biology, University of California Davis, Davis, California; and Northern California Veterans Affairs Health Systems, Mather, California
| | - Leslie M Baehr
- Membrane Biology, University of California Davis, Davis, California; and
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30
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Role of neuregulin-1β in dexamethasone-enhanced surfactant synthesis in fetal type II cells. FEBS Lett 2014; 588:975-80. [PMID: 24530532 DOI: 10.1016/j.febslet.2014.01.057] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 01/16/2014] [Accepted: 01/22/2014] [Indexed: 11/24/2022]
Abstract
It is well established that glucocorticoids elevate the production of fibroblast-pneumocyte factor (FPF), which induces type II cells to synthesize surfactant phospholipids. FPF, however, has not been identified and it is not clear whether it is a single factor or a complex mixture of factors. In this study it has been shown that, when lung fibroblasts are exposed to dexamethasone, the concentration of neuregulin-1β (NRG1β) in conditioned medium is elevated 2-fold (P<0.05), even though NRG1β gene expression is unaffected. This, together with the finding that exposure of type II cells to NRG1β directly stimulates by 3-fold the rate of phospholipid synthesis (P<0.05), suggests that NRG1β is a component of FPF that promotes lung development.
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Graça FA, Gonçalves DAP, Silveira WA, Lira EC, Chaves VE, Zanon NM, Garófalo MAR, Kettelhut IC, Navegantes LCC. Epinephrine depletion exacerbates the fasting-induced protein breakdown in fast-twitch skeletal muscles. Am J Physiol Endocrinol Metab 2013; 305:E1483-94. [PMID: 24169047 DOI: 10.1152/ajpendo.00267.2013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The physiological role of epinephrine in the regulation of skeletal muscle protein metabolism under fasting is unknown. We examined the effects of plasma epinephrine depletion, induced by adrenodemedullation (ADMX), on muscle protein metabolism in fed and 2-day-fasted rats. In fed rats, ADMX for 10 days reduced muscle mass, the cross-sectional area of extensor digitorum longus (EDL) muscle fibers, and the phosphorylation levels of Akt. In addition, ADMX led to a compensatory increase in muscle sympathetic activity, as estimated by the rate of norepinephrine turnover; this increase was accompanied by high rates of muscle protein synthesis. In fasted rats, ADMX exacerbated fasting-induced proteolysis in EDL but did not affect the low rates of protein synthesis. Accordingly, ADMX activated lysosomal proteolysis and further increased the activity of the ubiquitin (Ub)-proteasome system (UPS). Moreover, expression of the atrophy-related Ub ligases atrogin-1 and MuRF1 and the autophagy-related genes LC3b and GABARAPl1 were upregulated in EDL muscles from ADMX-fasted rats compared with sham-fasted rats, and ADMX reduced cAMP levels and increased fasting-induced Akt dephosphorylation. Unlike that observed for EDL muscles, soleus muscle proteolysis and Akt phosphorylation levels were not affected by ADMX. In isolated EDL, epinephrine reduced the basal UPS activity and suppressed overall proteolysis and atrogin-1 and MuRF1 induction following fasting. These data suggest that epinephrine released from the adrenal medulla inhibits fasting-induced protein breakdown in fast-twitch skeletal muscles, and these antiproteolytic effects on the UPS and lysosomal system are apparently mediated through a cAMP-Akt-dependent pathway, which suppresses ubiquitination and autophagy.
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Affiliation(s)
- Flávia A Graça
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
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32
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Verhees KJP, Pansters NAM, Baarsma HA, Remels AHV, Haegens A, de Theije CC, Schols AMWJ, Gosens R, Langen RCJ. Pharmacological inhibition of GSK-3 in a guinea pig model of LPS-induced pulmonary inflammation: II. Effects on skeletal muscle atrophy. Respir Res 2013; 14:117. [PMID: 24180420 PMCID: PMC4176095 DOI: 10.1186/1465-9921-14-117] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 10/14/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Chronic obstructive pulmonary disease (COPD) is accompanied by pulmonary inflammation and associated with extra-pulmonary manifestations, including skeletal muscle atrophy. Glycogen synthase kinase-3 (GSK-3) has been implicated in the regulation of muscle protein- and myonuclear turnover; two crucial processes that determine muscle mass. In the present study we investigated the effect of the selective GSK-3 inhibitor SB216763 on muscle mass in a guinea pig model of lipopolysaccharide (LPS)-induced pulmonary inflammation-associated muscle atrophy. METHODS Guinea pigs were pretreated with either intranasally instilled SB216763 or corresponding vehicle prior to each LPS/saline challenge twice weekly. Pulmonary inflammation was confirmed and indices of muscle mass were determined after 12 weeks. Additionally, cultured skeletal muscle cells were incubated with tumor necrosis factor α (TNF-α) or glucocorticoids (GCs) to model the systemic effects of pulmonary inflammation on myogenesis, in the presence or absence of GSK-3 inhibitors. RESULTS Repeated LPS instillation induced muscle atrophy based on muscle weight and muscle fiber cross sectional area. Intriguingly, GSK-3 inhibition using SB216763 prevented the LPS-induced muscle mass decreases and myofiber atrophy. Indices of protein turnover signaling were unaltered in guinea pig muscle. Interestingly, inhibition of myogenesis of cultured muscle cells by TNF-α or synthetic GCs was prevented by GSK-3 inhibitors. CONCLUSIONS In a guinea pig model of LPS-induced pulmonary inflammation, GSK-3 inhibition prevents skeletal muscle atrophy without affecting pulmonary inflammation. Resistance to inflammation- or GC-induced impairment of myogenic differentiation, imposed by GSK-3 inhibition, suggests that sustained myogenesis may contribute to muscle mass maintenance despite persistent pulmonary inflammation. Collectively, these results warrant further exploration of GSK-3 as a potential novel drug target to prevent or reverse muscle wasting in COPD.
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Affiliation(s)
- Koen J P Verhees
- Department of Respiratory Medicine, School for Nutrition, Toxicology and Metabolism (NUTRIM), Maastricht University Medical Centre + (MUMC+), PO box 5800, 6202, AZ Maastricht, The Netherlands.
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33
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Yoshida T, Tabony AM, Galvez S, Mitch WE, Higashi Y, Sukhanov S, Delafontaine P. Molecular mechanisms and signaling pathways of angiotensin II-induced muscle wasting: potential therapeutic targets for cardiac cachexia. Int J Biochem Cell Biol 2013; 45:2322-32. [PMID: 23769949 DOI: 10.1016/j.biocel.2013.05.035] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 05/28/2013] [Accepted: 05/29/2013] [Indexed: 02/07/2023]
Abstract
Cachexia is a serious complication of many chronic diseases, such as congestive heart failure (CHF) and chronic kidney disease (CKD). Many factors are involved in the development of cachexia, and there is increasing evidence that angiotensin II (Ang II), the main effector molecule of the renin-angiotensin system (RAS), plays an important role in this process. Patients with advanced CHF or CKD often have increased Ang II levels and cachexia, and angiotensin-converting enzyme (ACE) inhibitor treatment improves weight loss. In rodent models, an increase in systemic Ang II leads to weight loss through increased protein breakdown, reduced protein synthesis in skeletal muscle and decreased appetite. Ang II activates the ubiquitin-proteasome system via generation of reactive oxygen species and via inhibition of the insulin-like growth factor-1 signaling pathway. Furthermore, Ang II inhibits 5' AMP-activated protein kinase (AMPK) activity and disrupts normal energy balance. Ang II also increases cytokines and circulating hormones such as tumor necrosis factor-α, interleukin-6, serum amyloid-A, glucocorticoids and myostatin, which regulate muscle protein synthesis and degradation. Ang II acts on hypothalamic neurons to regulate orexigenic/anorexigenic neuropeptides, such as neuropeptide-Y, orexin and corticotropin-releasing hormone, leading to reduced appetite. Also, Ang II may regulate skeletal muscle regenerative processes. Several clinical studies have indicated that blockade of Ang II signaling via ACE inhibitors or Ang II type 1 receptor blockers prevents weight loss and improves muscle strength. Thus the RAS is a promising target for the treatment of muscle atrophy in patients with CHF and CKD. This article is part of a Directed Issue entitled: Molecular basis of muscle wasting.
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Affiliation(s)
- Tadashi Yoshida
- Heart and Vascular Institute, Tulane University School of Medicine, New Orleans, LA, United States
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Braun TP, Grossberg AJ, Krasnow SM, Levasseur PR, Szumowski M, Zhu XX, Maxson JE, Knoll JG, Barnes AP, Marks DL. Cancer- and endotoxin-induced cachexia require intact glucocorticoid signaling in skeletal muscle. FASEB J 2013; 27:3572-82. [PMID: 23733748 DOI: 10.1096/fj.13-230375] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Cachexia is a wasting condition defined by skeletal muscle atrophy in the setting of systemic inflammation. To explore the site at which inflammatory mediators act to produce atrophy in vivo, we utilized mice with a conditional deletion of the inflammatory adaptor protein myeloid differentiation factor 88 (MyD88). Although whole-body MyD88-knockout (wbMyD88KO) mice resist skeletal muscle atrophy in response to LPS, muscle-specific deletion of MyD88 is not protective. Furthermore, selective reexpression of MyD88 in the muscle of wbMyD88KO mice via electroporation fails to restore atrophy gene induction by LPS. To evaluate the role of glucocorticoids as the inflammation-induced mediator of atrophy in vivo, we generated mice with targeted deletion of the glucocorticoid receptor in muscle (mGRKO mice). Muscle-specific deletion of the glucocorticoid receptor affords a 71% protection against LPS-induced atrophy compared to control animals. Furthermore, mGRKO mice exhibit 77% less skeletal muscle atrophy than control animals in response to tumor growth. These data demonstrate that glucocorticoids are a major determinant of inflammation-induced atrophy in vivo and play a critical role in the pathogenesis of endotoxemic and cancer cachexia.
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Affiliation(s)
- Theodore P Braun
- Papé Family Pediatric Research Institute, Oregon Health and Science University, 3181 SW Sam Jackson Park Rd., Mail Code L-481, Portland, OR 97239, USA
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Wing SS. Deubiquitinases in skeletal muscle atrophy. Int J Biochem Cell Biol 2013; 45:2130-5. [PMID: 23680672 DOI: 10.1016/j.biocel.2013.05.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 05/03/2013] [Indexed: 11/29/2022]
Abstract
The ubiquitin proteasome system plays a critical role in skeletal muscle atrophy. A large body of research has revealed that many ubiquitin ligases are induced and play an important role in mediating the wasting. However, relatively little is known about the roles of deubiquitinases in this process. Although it might be expected that deubiquitinases would be downregulated in atrophying muscles to promote ubiquitination and degradation of muscle proteins, this has not to date been demonstrated. Instead several deubiquitinases are induced in atrophying muscle, in particular USP19 and USP14. USP19, USP2 and A20 are also implicated in myogenesis. USP19 has been most studied to date. Its expression is increased in both systemic and disuse forms of atrophy and can be regulated through a p38 MAP kinase signaling pathway. In cultured muscle cells, it decreases the expression of myofibrillar proteins by apparently suppressing their transcription indicating that the ubiquitin proteasome system may be activated in skeletal muscle to not only increase protein degradation, but also to suppress protein synthesis. Deubiquitinases may be upregulated in atrophy in order to maintain the pool of free ubiquitin required for the increased overall conjugation and degradation of muscle proteins as well as to regulate the stability and function of proteins that are essential in mediating the wasting. Although deubiquitinases are not well studied, these early insights indicate that some of these enzymes play important roles and may be therapeutic targets for the prevention and treatment of muscle atrophy. This article is part of a Directed Issue entitled: Molecular basis of muscle wasting.
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Affiliation(s)
- Simon S Wing
- Polypeptide Laboratory, Department of Medicine, McGill University and McGill University Health Centre, Canada.
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Shavlakadze T, Anwari T, Soffe Z, Cozens G, Mark PJ, Gondro C, Grounds MD. Impact of fasting on the rhythmic expression of myogenic and metabolic factors in skeletal muscle of adult mice. Am J Physiol Cell Physiol 2013; 305:C26-35. [PMID: 23596176 DOI: 10.1152/ajpcell.00027.2013] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Circadian rhythms and metabolism are tightly integrated, and rhythmic expression of metabolic factors is common in homeostatic processes. We measured the temporal changes in the expression of myogenic regulatory factors and expression and activity level of molecules involved in protein metabolism in skeletal muscles and livers in mice and examined the impact of fasting. Tissues were collected over 24 h (at zeitgeber times ZT1, ZT5, ZT9, ZT13, ZT17, ZT21, and ZT1 the following day) from adult male C57Bl/6J mice that had been either freely fed or fasted for 24 h. In skeletal muscle, there was a robust rise in the mRNA expression of the myogenic regulatory factors MyoD and myogenin during dark hours which was strongly suppressed by fasting. Circadian pattern was observed for mRNA of MuRF1, Akt1, and ribosomal protein S6 in muscles in fed and fasted mice and for Fbxo32 in fed mice. Activity (phosphorylation) levels of Akt(Ser473) displayed temporal regulation in fasted (but not fed) mice and were high at ZT9. Fasting caused significant reductions in phosphorylation for both Akt and S6 in muscles, indicative of inactivation. Hepatic phosphorylated Akt(Ser473) and S6(Ser235/236) proteins did not exhibit daily rhythms. Fasting significantly reduced hepatic Akt(473) phosphorylation compared with fed levels, although (unlike in muscle) it did not affect S6(Ser235/236) phosphorylation. This in vivo circadian study addresses for the first time the signaling activities of key molecules related to protein turnover and their possible cross-regulation of expression of genes related to protein degradation.
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Affiliation(s)
- T Shavlakadze
- School of Anatomy, Physiology and Human Biology, the University of Western Australia, Crawley, Western Australia, Australia.
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Moreira JBN, Bechara LRG, Bozi LHM, Jannig PR, Monteiro AWA, Dourado PM, Wisløff U, Brum PC. High- versus moderate-intensity aerobic exercise training effects on skeletal muscle of infarcted rats. J Appl Physiol (1985) 2013; 114:1029-41. [DOI: 10.1152/japplphysiol.00760.2012] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Poor skeletal muscle performance was shown to strongly predict mortality and long-term prognosis in a variety of diseases, including heart failure (HF). Despite the known benefits of aerobic exercise training (AET) in improving the skeletal muscle phenotype in HF, the optimal exercise intensity to elicit maximal outcomes is still under debate. Therefore, the aim of the present study was to compare the effects of high-intensity AET with those of a moderate-intensity protocol on skeletal muscle of infarcted rats. Wistar rats underwent myocardial infarction (MI) or sham surgery. MI groups were submitted either to an untrained (MI-UNT); moderate-intensity (MI-CMT, 60% V̇o2 max); or matched volume, high-intensity AET (MI-HIT, intervals at 85% V̇o2 max) protocol. High-intensity AET (HIT) was superior to moderate-intensity AET (CMT) in improving aerobic capacity, assessed by treadmill running tests. Cardiac contractile function, measured by echocardiography, was equally improved by both AET protocols. CMT and HIT prevented the MI-induced decay of skeletal muscle citrate synthase and hexokinase maximal activities, and increased glycogen content, without significant differences between protocols. Similar improvements in skeletal muscle redox balance and deactivation of the ubiquitin-proteasome system were also observed after CMT and HIT. Such intracellular findings were accompanied by prevented skeletal muscle atrophy in both MI-CMT and MI-HIT groups, whereas no major differences were observed between protocols. Taken together, our data suggest that despite superior effects of HIT in improving functional capacity, skeletal muscle adaptations were remarkably similar among protocols, leading to the conclusion that skeletal myopathy in infarcted rats was equally prevented by either moderate-intensity or high-intensity AET.
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Affiliation(s)
- José B. N. Moreira
- School of Physical Education and Sport, University of São Paulo, São Paulo, SP, Brazil
| | - Luiz R. G. Bechara
- School of Physical Education and Sport, University of São Paulo, São Paulo, SP, Brazil
| | - Luiz H. M. Bozi
- School of Physical Education and Sport, University of São Paulo, São Paulo, SP, Brazil
| | - Paulo R. Jannig
- School of Physical Education and Sport, University of São Paulo, São Paulo, SP, Brazil
| | - Alex W. A. Monteiro
- School of Physical Education and Sport, University of São Paulo, São Paulo, SP, Brazil
| | - Paulo M. Dourado
- Heart Institute, Faculty of Medicine, University of São Paulo, São Paulo, SP, Brazil; and
| | - Ulrik Wisløff
- K.G. Jebsen Center of Exercise in Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Patricia C. Brum
- School of Physical Education and Sport, University of São Paulo, São Paulo, SP, Brazil
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Roohk DJ, Mascharak S, Khambatta C, Leung H, Hellerstein M, Harris C. Dexamethasone-mediated changes in adipose triacylglycerol metabolism are exaggerated, not diminished, in the absence of a functional GR dimerization domain. Endocrinology 2013; 154:1528-39. [PMID: 23493372 PMCID: PMC3602623 DOI: 10.1210/en.2011-1047] [Citation(s) in RCA: 9] [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: 01/06/2023]
Abstract
The glucocorticoid (GC) receptor (GR) has multiple effector mechanisms, including dimerization-mediated transactivation of target genes via DNA binding and transcriptional repression mediated by protein-protein interactions. Much attention has been focused on developing selective GR modulators that would dissociate adverse effects from therapeutic anti-inflammatory effects. The GR(dim/dim) mouse has a mutation in the dimerization domain of GR and has been shown to have attenuated transactivation with intact repression. To understand the role of GR dimerization-dependent targets in multiple tissues, we measured metabolic fluxes through several disease-relevant GC target pathways using heavy water labeling and mass spectrometry in wild-type and GR(dim/dim) mice administered the potent GC dexamethasone (DEX). Absolute triglyceride synthesis was increased in both wild-type and GR(dim/dim) mice by DEX in the inguinal and epididymal fat depots. GR(dim/dim) mice showed an exaggerated response to DEX in both depots. De novo lipogenesis was also greatly increased in both depots in response to DEX in GR(dim/dim), but not wild-type mice. In contrast, the inhibitory effect of DEX on bone and skin collagen synthesis rates was greater in wild-type compared with GR(dim/dim) mice. Wild-type mice were more sensitive to DEX-dependent decreases in insulin sensitivity than GR(dim/dim) mice. Wild-type and GR(dim/dim) mice were equally sensitive to DEX-dependent decreases in muscle protein synthesis. Chronic elevation of GCs in GR(dim/dim) mice results in severe runting and lethality. In conclusion, some metabolic effects of GC treatment are exaggerated in adipose tissue of GR(dim/dim) mice, suggesting that selective GR modulators based on dissociating GR transactivation from repression should be evaluated carefully.
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Affiliation(s)
- Donald J Roohk
- Department of Nutritional Science and Toxicology, University of California Berkeley, Berkeley, California 94720, USA
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C1-Ten is a protein tyrosine phosphatase of insulin receptor substrate 1 (IRS-1), regulating IRS-1 stability and muscle atrophy. Mol Cell Biol 2013; 33:1608-20. [PMID: 23401856 DOI: 10.1128/mcb.01447-12] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Muscle atrophy occurs under various catabolic conditions, including insulin deficiency, insulin resistance, or increased levels of glucocorticoids. This results from reduced levels of insulin receptor substrate 1 (IRS-1), leading to decreased phosphatidylinositol 3-kinase activity and thereby activation of FoxO transcription factors. However, the precise mechanism of reduced IRS-1 under a catabolic condition is unknown. Here, we report that C1-Ten is a novel protein tyrosine phosphatase (PTPase) of IRS-1 that acts as a mediator to reduce IRS-1 under a catabolic condition, resulting in muscle atrophy. C1-Ten preferentially dephosphorylated Y612 of IRS-1, which accelerated IRS-1 degradation. These findings suggest a novel type of IRS-1 degradation mechanism which is dependent on C1-Ten and extends our understanding of the molecular mechanism of muscle atrophy under catabolic conditions. C1-Ten expression is increased by catabolic glucocorticoid and decreased by anabolic insulin. Reflecting these hormonal regulations, the muscle C1-Ten is upregulated in atrophy but downregulated in hypertrophy. This reveals a previously unidentified role of C1-Ten as a relevant PTPase contributing to skeletal muscle atrophy.
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Kukreti H, Amuthavalli K, Harikumar A, Sathiyamoorthy S, Feng PZ, Anantharaj R, Tan SLK, Lokireddy S, Bonala S, Sriram S, McFarlane C, Kambadur R, Sharma M. Muscle-specific microRNA1 (miR1) targets heat shock protein 70 (HSP70) during dexamethasone-mediated atrophy. J Biol Chem 2013; 288:6663-78. [PMID: 23297411 DOI: 10.1074/jbc.m112.390369] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
High doses of dexamethasone (Dex) or myostatin (Mstn) induce severe atrophy of skeletal muscle. Here we show a novel microRNA1 (miR1)-mediated mechanism through which Dex promotes skeletal muscle atrophy. Using both C2C12 myotubes and mouse models of Dex-induced atrophy we show that Dex induces miR1 expression through glucocorticoid receptor (GR). We further show that Mstn treatment facilitates GR nuclear translocation and thereby induces miR1 expression. Inhibition of miR1 in C2C12 myotubes attenuated the Dex-induced increase in atrophy-related proteins confirming a role for miR1 in atrophy. Analysis of miR1 targets revealed that HSP70 is regulated by miR1 during atrophy. Our results demonstrate that increased miR1 during atrophy reduced HSP70 levels, which resulted in decreased phosphorylation of AKT, as HSP70 binds to and protects phosphorylation of AKT. We further show that loss of pAKT leads to decreased phosphorylation, and thus, enhanced activation of FOXO3, up-regulation of MuRF1 and Atrogin-1, and progression of skeletal muscle atrophy. Based on these results, we propose a model whereby Dex- and Mstn-mediated atrophic signals are integrated through miR1, which then either directly or indirectly, inhibits the proteins involved in providing protection against atrophy.
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Affiliation(s)
- Himani Kukreti
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 8 Medical Drive MD7, Singapore 117597
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41
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Fanzani A, Conraads VM, Penna F, Martinet W. Molecular and cellular mechanisms of skeletal muscle atrophy: an update. J Cachexia Sarcopenia Muscle 2012; 3:163-79. [PMID: 22673968 PMCID: PMC3424188 DOI: 10.1007/s13539-012-0074-6] [Citation(s) in RCA: 234] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Accepted: 05/13/2012] [Indexed: 02/06/2023] Open
Abstract
Skeletal muscle atrophy is defined as a decrease in muscle mass and it occurs when protein degradation exceeds protein synthesis. Potential triggers of muscle wasting are long-term immobilization, malnutrition, severe burns, aging as well as various serious and often chronic diseases, such as chronic heart failure, obstructive lung disease, renal failure, AIDS, sepsis, immune disorders, cancer, and dystrophies. Interestingly, a cooperation between several pathophysiological factors, including inappropriately adapted anabolic (e.g., growth hormone, insulin-like growth factor 1) and catabolic proteins (e.g., tumor necrosis factor alpha, myostatin), may tip the balance towards muscle-specific protein degradation through activation of the proteasomal and autophagic systems or the apoptotic pathway. Based on the current literature, we present an overview of the molecular and cellular mechanisms that contribute to muscle wasting. We also focus on the multifacetted therapeutic approach that is currently employed to prevent the development of muscle wasting and to counteract its progression. This approach includes adequate nutritional support, implementation of exercise training, and possible pharmacological compounds.
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Affiliation(s)
- Alessandro Fanzani
- Department of Biomedical Sciences and Biotechnologies and Interuniversitary Institute of Myology (IIM), University of Brescia, viale Europa 11, 25123, Brescia, Italy,
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Braun TP, Zhu X, Szumowski M, Scott GD, Grossberg AJ, Levasseur PR, Graham K, Khan S, Damaraju S, Colmers WF, Baracos VE, Marks DL. Central nervous system inflammation induces muscle atrophy via activation of the hypothalamic-pituitary-adrenal axis. ACTA ACUST UNITED AC 2011; 208:2449-63. [PMID: 22084407 PMCID: PMC3256966 DOI: 10.1084/jem.20111020] [Citation(s) in RCA: 147] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Systemic and CNS-delimited inflammation triggers skeletal muscle catabolism in a manner dependent on glucocorticoid signaling. Skeletal muscle catabolism is a co-morbidity of many chronic diseases and is the result of systemic inflammation. Although direct inflammatory cytokine action on muscle promotes atrophy, nonmuscle sites of action for inflammatory mediators are less well described. We demonstrate that central nervous system (CNS)–delimited interleukin 1β (IL-1β) signaling alone can evoke a catabolic program in muscle, rapidly inducing atrophy. This effect is dependent on hypothalamic–pituitary–adrenal (HPA) axis activation, as CNS IL-1β–induced atrophy is abrogated by adrenalectomy. Furthermore, we identified a glucocorticoid-responsive gene expression pattern conserved in models of acute and chronic inflammatory muscle atrophy. In contrast with studies suggesting that the direct action of inflammatory cytokines on muscle is sufficient to induce catabolism, adrenalectomy also blocks the atrophy program in response to systemic inflammation, demonstrating that glucocorticoids are requisite for this process. Additionally, circulating levels of glucocorticoids equivalent to those produced under inflammatory conditions are sufficient to cause profound muscle wasting. Together, these data suggest that a significant component of inflammation-induced muscle catabolism occurs indirectly via a relay in the CNS.
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Affiliation(s)
- Theodore P Braun
- Papé Family Pediatric Research Institute, Oregon Health & Science University, Portland, OR 97239, USA
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Verhees KJP, Schols AMWJ, Kelders MCJM, Op den Kamp CMH, van der Velden JLJ, Langen RCJ. Glycogen synthase kinase-3β is required for the induction of skeletal muscle atrophy. Am J Physiol Cell Physiol 2011; 301:C995-C1007. [DOI: 10.1152/ajpcell.00520.2010] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Skeletal muscle atrophy commonly occurs in acute and chronic disease. The expression of the muscle-specific E3 ligases atrogin-1 (MAFbx) and muscle RING finger 1 (MuRF1) is induced by atrophy stimuli such as glucocorticoids or absence of IGF-I/insulin and subsequent Akt signaling. We investigated whether glycogen synthase kinase-3β (GSK-3β), a downstream molecule in IGF-I/Akt signaling, is required for basal and atrophy stimulus-induced expression of atrogin-1 and MuRF1, and myofibrillar protein loss in C2C12 skeletal myotubes. Abrogation of basal IGF-I signaling, using LY294002, resulted in a prominent induction of atrogin-1 and MuRF1 mRNA and was accompanied by a loss of myosin heavy chain fast (MyHC-f) and myosin light chains 1 (MyLC-1) and -3 (MyLC-3). The synthetic glucocorticoid dexamethasone (Dex) also induced the expression of both atrogenes and likewise resulted in the loss of myosin protein abundance. Genetic ablation of GSK-3β using small interfering RNA resulted in specific sparing of MyHC-f, MyLC-1, and MyLC-3 protein levels after Dex treatment or impaired IGF-I/Akt signaling. Interestingly, loss of endogenous GSK-3β suppressed both basal and atrophy stimulus-induced atrogin-1 and MuRF1 expression, whereas pharmacological GSK-3β inhibition, using CHIR99021 or LiCl, only reduced atrogin-1 mRNA levels in response to LY294002 or Dex. In conclusion, our data reveal that myotube atrophy and myofibrillar protein loss are GSK-3β dependent, and demonstrate for the first time that basal and atrophy stimulus-induced atrogin-1 mRNA expression requires GSK-3β enzymatic activity, whereas MuRF1 expression depends solely on the physical presence of GSK-3β.
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Affiliation(s)
- Koen J. P. Verhees
- Department of Respiratory Medicine, School for Nutrition, Toxicology and Metabolism (NUTRIM), Maastricht University Medical Centre (MUMC+), Maastricht, the Netherlands
| | - Annemie M. W. J. Schols
- Department of Respiratory Medicine, School for Nutrition, Toxicology and Metabolism (NUTRIM), Maastricht University Medical Centre (MUMC+), Maastricht, the Netherlands
| | - Marco C. J. M. Kelders
- Department of Respiratory Medicine, School for Nutrition, Toxicology and Metabolism (NUTRIM), Maastricht University Medical Centre (MUMC+), Maastricht, the Netherlands
| | - Céline M. H. Op den Kamp
- Department of Respiratory Medicine, School for Nutrition, Toxicology and Metabolism (NUTRIM), Maastricht University Medical Centre (MUMC+), Maastricht, the Netherlands
| | - Jos L. J. van der Velden
- Department of Respiratory Medicine, School for Nutrition, Toxicology and Metabolism (NUTRIM), Maastricht University Medical Centre (MUMC+), Maastricht, the Netherlands
| | - Ramon C. J. Langen
- Department of Respiratory Medicine, School for Nutrition, Toxicology and Metabolism (NUTRIM), Maastricht University Medical Centre (MUMC+), Maastricht, the Netherlands
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Abstract
Muscle atrophy (cachexia) is a muscle wasting syndrome associated with several pathological conditions in humans such as congestive heart failure, diabetes, AIDS, cancer and renal failure, and the presence of cachexia worsens outcome. Many of the conditions associated with cachexia are accompanied by stimulation of the renin-angiotensin system and elevation in angiotensin II (ang II) levels. Ang II infusion induces skeletal muscle atrophy in rodents and mechanisms include increased expression of the E3 ligases atrogin-1/MuRF-1, an elevated rate of ubiquitin-proteasome mediated proteolysis and increased reactive oxygen species (ROS) levels, closely mimicking conditions of human cachexia. Ang II-induced oxidative stress contributes to muscle atrophy in a mouse model. Nicotinamide adenine dinucleotide phosphate oxidase- and mitochondria-derived ROS contribute to ang II-induced oxidative stress. Specific targeting of ROS and nicotinamide adenine dinucleotide phosphate oxidase/mitochondria cross-talk could be a beneficial, novel therapy to treat cachexia.
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Baehr LM, Furlow JD, Bodine SC. Muscle sparing in muscle RING finger 1 null mice: response to synthetic glucocorticoids. J Physiol 2011; 589:4759-76. [PMID: 21807613 DOI: 10.1113/jphysiol.2011.212845] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Skeletal muscle atrophy occurs under a variety of conditions and can result from alterations in both protein synthesis and protein degradation. The muscle-specific E3 ubiquitin ligases, MuRF1 and MAFbx, are excellent markers of muscle atrophy and increase under divergent atrophy-inducing conditions such as denervation and glucocorticoid treatment. While deletion of MuRF1 or MAFbx has been reported to spare muscle mass following 14 days of denervation, their role in other atrophy-inducing conditions is unclear. The goal of this study was to determine whether deletion of MuRF1 or MAFbx attenuates muscle atrophy after 2 weeks of treatment with the synthetic glucocorticoid dexamethasone (DEX). The response of the triceps surae (TS) and tibialis anterior (TA) muscles to 14 days of DEX treatment (3 mg kg(-1) day(-1)) was examined in 4 month-old male and female wild type (WT) and MuRF1 or MAFbx knock out (KO) mice. Following 14 days of DEX treatment, muscle wet weight was significantly decreased in the TS and TA of WT mice. Comparison of WT and KO mice following DEX treatment revealed significant sparing of mass in both sexes of the MuRF1 KO mice, but no muscle sparing in MAFbx KO mice. Further analysis of the MuRF1 KO mice showed significant sparing of fibre cross-sectional area and tension output in the gastrocnemius (GA) after DEX treatment. Muscle sparing in the MuRF1 KO mice was related to maintenance of protein synthesis, with no observed increases in protein degradation in either WT or MuRF1 KO mice. These results demonstrate that MuRF1 and MAFbx do not function similarly under all atrophy models, and that the primary role of MuRF1 may extend beyond controlling protein degradation via the ubiquitin proteasome system.
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Affiliation(s)
- Leslie M Baehr
- Department of Neurobiology, Physiology, and Behavior, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA
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46
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She P, Zhang Z, Marchionini D, Diaz WC, Jetton TJ, Kimball SR, Vary TC, Lang CH, Lynch CJ. Molecular characterization of skeletal muscle atrophy in the R6/2 mouse model of Huntington's disease. Am J Physiol Endocrinol Metab 2011; 301:E49-61. [PMID: 21505144 PMCID: PMC3129844 DOI: 10.1152/ajpendo.00630.2010] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Huntington's disease (HD), a neurodegenerative disorder caused by mutant huntingtin, is characterized by a catabolic phenotype. To determine the mechanisms underlying muscle wasting, we examined key signal transduction pathways governing muscle protein metabolism, apoptosis, and autophagy in R6/2 mice, a well-characterized transgenic model of HD. R6/2 mice exhibited increased adiposity, elevated energy expenditure, and decreased body weight and lean mass without altered food intake. Severe skeletal muscle wasting accounted for a majority of the weight loss. Protein synthesis was unexpectedly increased 19% in gastrocnemius muscle, which was associated with overactivation of basal and refeeding-stimulated mammalian target of rapamycin (mTOR) signaling, elevated Akt expression and Ser(473) phosphorylation, and decreased AMPK Thr(172) phosphorylation. Moreover, mRNA abundance of atrogenes muscle ring finger-1 and atrophy F-box, was markedly attenuated during fasting and refeeding, and the urinary excretion of 3-methylhistidine was decreased, arguing against a role for the ubiquitin proteasome-mediated proteolysis in the atrophy. In contrast, mRNA expression of several caspase genes and genes involved in the extrinsic or intrinsic apoptotic pathway, caspase-3/7, -8, and -9 activity, protein abundance of caspase-3 and -9, Fas, and Fadd, and cytochrome c release were elevated. Protein expressions of LC3B-I and -II, beclin-I, and atg5 and -7 in muscle were upregulated. Thus, mutant huntingtin in skeletal muscle results in increased protein synthesis and mTOR signaling, which is countered by activation of the apoptotic and autophagic pathways, contributing to an overall catabolic phenotype and the severe muscle wasting.
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Affiliation(s)
- Pengxiang She
- Department of Cellular and Molecular Physiology, the Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA.
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Wing SS, Lecker SH, Jagoe RT. Proteolysis in illness-associated skeletal muscle atrophy: from pathways to networks. Crit Rev Clin Lab Sci 2011; 48:49-70. [PMID: 21699435 DOI: 10.3109/10408363.2011.586171] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Improvements in health in the past decades have resulted in increased numbers of the elderly in both developed and developing regions of the world. Advances in therapy have also increased the prevalence of patients with chronic and degenerative diseases. Muscle wasting, a feature of most chronic diseases, is prominent in the elderly and contributes to both morbidity and mortality. A major research goal has been to identify the proteolytic system(s) that is responsible for the degradation of proteins that occurs in muscle atrophy. Findings over the past 20 years have clearly confirmed an important role of the ubiquitin proteasome system in mediating muscle proteolysis, particularly that of myofibrillar proteins. However, recent observations have provided evidence that autophagy, calpains and caspases also contribute to the turnover of muscle proteins in catabolic states, and furthermore, that these diverse proteolytic systems interact with each other at various levels. Importantly, a number of intracellular signaling pathways such as the IGF1/AKT, myostatin/Smad, PGC1, cytokine/NFκB, and AMPK pathways are now known to interact and can regulate some of these proteolytic systems in a coordinated manner. A number of loss of function studies have identified promising therapeutic approaches to the prevention and treatment of wasting. However, additional biomarkers and other approaches to improve early identification of patients who would benefit from such treatment need to be developed. The current data suggests a network of interacting proteolytic and signaling pathways in muscle. Future studies are needed to improve understanding of the nature and control of these interactions and how they work to preserve muscle function under various states of growth and atrophy.
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Affiliation(s)
- Simon S Wing
- Departments of Medicine, McGill University and McGill University Health Centre Research Institute, Montreal, Quebec, Canada.
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48
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Gene Expression of Muscle-Specific Ubiquitin Ligase, Atrogin-1/MAFbx, Positively Correlates with Skeletal Muscle Proteolysis in Food-Deprived Broiler Chickens. J Poult Sci 2011. [DOI: 10.2141/jpsa.010093] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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49
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Buckley JD, Howe PRC. Long-chain omega-3 polyunsaturated fatty acids may be beneficial for reducing obesity-a review. Nutrients 2010; 2:1212-1230. [PMID: 22254005 PMCID: PMC3257626 DOI: 10.3390/nu2121212] [Citation(s) in RCA: 158] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Revised: 12/01/2010] [Accepted: 12/08/2010] [Indexed: 01/02/2023] Open
Abstract
Current recommendations for counteracting obesity advocate the consumption of a healthy diet and participation in regular physical activity, but many individuals have difficulty complying with these recommendations. Studies in rodents and humans have indicated that long-chain omega-3 polyunsaturated fatty acids (LC n-3 PUFA) potentially elicit a number of effects which might be useful for reducing obesity, including suppression of appetite, improvements in circulation which might facilitate nutrient delivery to skeletal muscle and changes in gene expression which shift metabolism toward increased accretion of lean tissue, enhanced fat oxidation and energy expenditure and reduced fat deposition. While LC n-3 PUFA supplementation has been shown to reduce obesity in rodents, evidence in humans is limited. Epidemiological associations between LC n-3 PUFA intakes and obesity are inconclusive but small cross-sectional studies have demonstrated inverse relationships between markers of LC n-3 PUFA status and markers of obesity. Human intervention trials indicate potential benefits of LC n-3 PUFA supplementation, especially when combined with energy-restricted diets or exercise, but more well-controlled and long-term trials are needed to confirm these effects and identify mechanisms of action.
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Affiliation(s)
- Jonathan D. Buckley
- Nutritional Physiology Research Centre, University of South Australia Adelaide, South Australia, 5000, Australia;
- Sansom Institute for Health Research, University of South Australia Adelaide, South Australia, 5000, Australia
- Author to whom correspondence should be addressed; ; Tel.: +61-8-8302-1853; Fax: +61-8-8302-2178
| | - Peter R. C. Howe
- Nutritional Physiology Research Centre, University of South Australia Adelaide, South Australia, 5000, Australia;
- Sansom Institute for Health Research, University of South Australia Adelaide, South Australia, 5000, Australia
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50
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Sixt SU, Jennissen HP, Winterhalter M, Laub M. Detection of ubiquityl-calmodulin conjugates with a novel high-molecular weight ubiquitylprotein-isopeptidase in rabbit tissues. Eur J Med Res 2010; 15:428-47. [PMID: 21156402 PMCID: PMC3352187 DOI: 10.1186/2047-783x-15-10-428] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The selective degradation of many proteins in eukaryotic cells is carried out by the ubiquitin system. In this pathway, proteins are targeted for degradation by covalent ligation to ubiquitin, a highly conserved protein [1]. Ubiquitylated proteins were degraded by the 26S proteasome in an ATP-depended manner. The degradation of ubiquitylated proteins were controlled by isopeptidase cleavage. A well characterised system of ubiquitylation and deubiquitylation is the calmodulin system in vitro [2]. Detection of ubiquityl-calmodulin conjugtates in vivo have not been shown so far. In this article we discuss the detection of ubiquitin calmodulin conjugates in vivo by incubation with a novel high-molecular weight ubiquitylprotein-isopeptidase in rabbit tissues. Proteins with a molecular weight of ubiquityl-calmodulin conjugates could be detected in all organs tested. Incubation with ubiquitylprotein-isopeptidase showed clearly a decrease of ubiquitin calmodulin conjugates in vivo with an origination of unbounded ubiquitin. These results suggest that only few ubiquitin calmodulin conjugates exist in rabbit tissues.
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Affiliation(s)
- S U Sixt
- Klinik für Anästhesiologie, Universitätsklinikum Düsseldorf, Germany.
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