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Kim YI, Lee H, Kim MJ, Jung CH, Kim YS, Ahn J. Identification of Peucedanum japonicum Thunb. extract components and their protective effects against dexamethasone-induced muscle atrophy. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2024; 128:155449. [PMID: 38518644 DOI: 10.1016/j.phymed.2024.155449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 11/21/2023] [Accepted: 02/11/2024] [Indexed: 03/24/2024]
Abstract
BACKGROUND Peucedanum japonicum Thunb. (PJ) is a vegetable widely consumed in East Asia and is known to have anticancer and anti-inflammatory effects. However, the effect of PJ on muscle atrophy remains elusive. PURPOSE This study aimed to investigate the effect of PJ and its active compound on dexamethasone (DEX)-induced muscle atrophy. METHODS We performed qualitative and quantitative analysis of PJ using ultra-performance liquid chromatography-mass spectrometry tandem mass spectrometry (UPLC-MS/MS) and high-performance liquid chromatography (HPLC), respectively. The efficacy of PJ and its main compound 4-caffeoylquinic acid (CQA) on muscle atrophy was evaluated in DEX-induced myotube atrophy and DEX-induced muscle atrophy in mouse myoblasts (C2C12) and C57BL/6 mice, in vitro and in vivo, respectively. RESULTS The UPLC-MS/MS and HPLC data showed that the concentration of 4-CQA in PJ was 18.845 mg/g. PJ and 4-CQA treatments significantly inhibited DEX-induced myotube atrophy by decreasing protein synthesis and glucocorticoid translocation to the nucleus in C2C12 myotubes. In addition, PJ enhanced myogenesis by upregulating myogenin and myogenic differentiation 1 in C2C12 cells. PJ supplementation effectively increased muscle function and mass, downregulated atrogenes, and decreased proteasome activity in C57BL/6 mice. Additionally, PJ effectively decreased the nuclear translocation of forkhead transcription factor 3 alpha by inhibiting glucocorticoid receptor. CONCLUSION Overall, PJ and its active compound 4-CQA alleviated skeletal muscle atrophy by inhibiting protein degradation. Hence, our findings present PJ as a potential novel pharmaceutical candidate for the treatment of muscle atrophy.
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Affiliation(s)
- Young In Kim
- Aging and Metabolism Research Group, Korea Food Research Institute, 245, Nongsaengmyeong-ro, Iseo-myeon, Wanju-gun, Jeollabuk-do 55365, South Korea; Department of Food Science and Technology, Jeonbuk National University, Jeonju-si, South Korea
| | - Hyunjung Lee
- Aging and Metabolism Research Group, Korea Food Research Institute, 245, Nongsaengmyeong-ro, Iseo-myeon, Wanju-gun, Jeollabuk-do 55365, South Korea
| | - Min Jung Kim
- Aging and Metabolism Research Group, Korea Food Research Institute, 245, Nongsaengmyeong-ro, Iseo-myeon, Wanju-gun, Jeollabuk-do 55365, South Korea
| | - Chang Hwa Jung
- Aging and Metabolism Research Group, Korea Food Research Institute, 245, Nongsaengmyeong-ro, Iseo-myeon, Wanju-gun, Jeollabuk-do 55365, South Korea; Department of Food Biotechnology, Korea National University of Science and Technology, Daejeon, South Korea
| | - Young-Soo Kim
- Department of Food Science and Technology, Jeonbuk National University, Jeonju-si, South Korea
| | - Jiyun Ahn
- Aging and Metabolism Research Group, Korea Food Research Institute, 245, Nongsaengmyeong-ro, Iseo-myeon, Wanju-gun, Jeollabuk-do 55365, South Korea; Department of Food Biotechnology, Korea National University of Science and Technology, Daejeon, South Korea.
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McLendon JM, Zhang X, Stein CS, Baehr LM, Bodine SC, Boudreau RL. A Specialized Centrosome-Proteasome Axis Mediates Proteostasis and Influences Cardiac Stress through Txlnb. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.12.580020. [PMID: 38405715 PMCID: PMC10888801 DOI: 10.1101/2024.02.12.580020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Background Centrosomes localize to perinuclear foci where they serve multifunctional roles, arranging the microtubule organizing center (MTOC) and anchoring ubiquitin-proteasome system (UPS) machinery. In mature cardiomyocytes, centrosomal proteins redistribute into a specialized perinuclear cage-like structure, and a potential centrosome-UPS interface has not been studied. Taxilin-beta (Txlnb), a cardiomyocyte-enriched protein, belongs to a family of centrosome adapter proteins implicated in protein quality control. We hypothesize that Txlnb plays a key role in centrosomal-proteasomal crosstalk in cardiomyocytes. Methods Integrative bioinformatics assessed centrosomal gene dysregulation in failing hearts. Txlnb gain/loss-of-function studies were conducted in cultured cardiomyocytes and mice. Txlnb's role in cardiac proteotoxicity and hypertrophy was examined using CryAB-R120G mice and transverse aortic constriction (TAC), respectively. Molecular modeling investigated Txlnb structure/function. Results Human failing hearts show consistent dysregulation of many centrosome-associated genes, alongside UPS-related genes. Txlnb emerged as a candidate regulator of cardiomyocyte proteostasis that localizes to the perinuclear centrosomal compartment. Txlnb's interactome strongly supports its involvement in cytoskeletal, microtubule, and UPS processes, particularly centrosome-related functions. Overexpressing Txlnb in cardiomyocytes reduced ubiquitinated protein accumulation and enhanced proteasome activity during hypertrophy. Txlnb-knockout (KO) mouse hearts exhibit proteasomal insufficiency and altered cardiac growth, evidenced by ubiquitinated protein accumulation, decreased 26Sβ5 proteasome activity, and lower mass with age. In Cryab-R120G mice, Txlnb loss worsened heart failure, causing lower ejection fractions. After TAC, Txlnb-KO mice also showed reduced ejection fraction, increased heart mass, and elevated ubiquitinated protein accumulation. Investigations into the molecular mechanisms revealed that Txlnb-KO did not affect proteasomal subunit expression but led to the upregulation of Txlna and several centrosomal proteins (Cep63, Ofd1, and Tubg) suggesting altered centrosomal dynamics. Structural predictions support Txlnb's role as a specialized centrosomal-adapter protein bridging centrosomes with proteasomes, confirmed by microtubule-dependent perinuclear localization. Conclusions Together, these data provide initial evidence connecting Txlnb to cardiac proteostasis, hinting at the potential importance of functional bridging between specialized centrosomes and UPS in cardiomyocytes.
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Zhang HJ, Wang BH, Wang X, Huang CP, Xu SM, Wang JL, Huang TE, Xiao WL, Tian XL, Lan XQ, Wang QQ, Xiang Y. Handelin alleviates cachexia- and aging-induced skeletal muscle atrophy by improving protein homeostasis and inhibiting inflammation. J Cachexia Sarcopenia Muscle 2024; 15:173-188. [PMID: 38009816 PMCID: PMC10834327 DOI: 10.1002/jcsm.13381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 09/07/2023] [Accepted: 09/25/2023] [Indexed: 11/29/2023] Open
Abstract
BACKGROUND Handelin is a bioactive compound from Chrysanthemum indicum L. that improves motor function and muscle integrity during aging in Caenorhabditis elegans. This study aimed to further evaluate the protective effects and molecular mechanisms of handelin in a mouse muscle atrophy model induced by cachexia and aging. METHODS A tumour necrosis factor (TNF)-α-induced atrophy model was used to examine handelin activity in cultured C2C12 myotubes in vitro. Lipopolysaccharide (LPS)-treated 8-week-old model mice and 23-month-old (aged) mice were used to examine the therapeutic effects of handelin on cachexia- and aging-induced muscle atrophy, respectively, in vivo. Protein and mRNA expressions were analysed by Western blotting, ELISA and quantitative PCR, respectively. Skeletal muscle mass was measured by histological analysis. RESULTS Handelin treatment resulted in an upregulation of protein levels of early (MyoD and myogenin) and late (myosin heavy chain, MyHC) differentiation markers in C2C12 myotubes (P < 0.05), and enhanced mitochondrial respiratory (P < 0.05). In TNF-α-induced myotube atrophy model, handelin maintained MyHC protein levels, increased insulin-like growth factor (Igf1) mRNA expression and phosphorylated protein kinase B protein levels (P < 0.05). Handelin also reduced atrogin-1 expression, inhibited nuclear factor-κB activation and reduced mRNA levels of interleukin (Il)6, Il1b and chemokine ligand 1 (Cxcl1) (P < 0.05). In LPS-treated mice, handelin increased body weight (P < 0.05), the weight (P < 0.01) and cross-sectional area (CSA) of the soleus muscle (P < 0.0001) and improved motor function (P < 0.05). In aged mice, handelin slightly increased the weight of the tibialis anterior muscle (P = 0.06) and CSA of the tibialis anterior and gastrocnemius muscles (P < 0.0001). In the tibialis anterior muscle of aged mice, handelin upregulated mRNA levels of Igf1 (P < 0.01), anti-inflammatory cytokine Il10 (P < 0.01), mitochondrial biogenesis genes (P < 0.05) and antioxidant-related enzymes (P < 0.05) and strengthened Sod and Cat enzyme activity (P < 0.05). Handelin also reduced lipid peroxidation and protein carbonylation, downregulated mRNA levels of Fbxo32, Mstn, Cxcl1, Il1b and Tnf (P < 0.05), and decreased IL-1β levels in serum (P < 0.05). Knockdown of Hsp70 or using an Hsp70 inhibitor abolished the ameliorating effects of handelin on myotube atrophy. CONCLUSIONS Handelin ameliorated cachexia- and aging-induced skeletal muscle atrophy in vitro and in vivo, by maintaining homeostasis of protein synthesis and degradation, possibly by inhibiting inflammation. Handelin is a potentially promising drug candidate for the treatment of muscle wasting.
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Affiliation(s)
- Hui-Jie Zhang
- Department of Metabolic Control and Aging, Human Aging Research Institute and School of Life Science, Nanchang University and Jiangxi Key Laboratory of Human Aging, Nanchang, China
| | - Ben-Hui Wang
- Department of Metabolic Control and Aging, Human Aging Research Institute and School of Life Science, Nanchang University and Jiangxi Key Laboratory of Human Aging, Nanchang, China
| | - Xiang Wang
- Department of Metabolic Control and Aging, Human Aging Research Institute and School of Life Science, Nanchang University and Jiangxi Key Laboratory of Human Aging, Nanchang, China
| | - Chun-Ping Huang
- Department of Metabolic Control and Aging, Human Aging Research Institute and School of Life Science, Nanchang University and Jiangxi Key Laboratory of Human Aging, Nanchang, China
| | - Si-Man Xu
- Department of Metabolic Control and Aging, Human Aging Research Institute and School of Life Science, Nanchang University and Jiangxi Key Laboratory of Human Aging, Nanchang, China
| | - Jia-Li Wang
- Department of Metabolic Control and Aging, Human Aging Research Institute and School of Life Science, Nanchang University and Jiangxi Key Laboratory of Human Aging, Nanchang, China
| | - Tian-E Huang
- Department of Metabolic Control and Aging, Human Aging Research Institute and School of Life Science, Nanchang University and Jiangxi Key Laboratory of Human Aging, Nanchang, China
| | - Wan-Li Xiao
- Department of Metabolic Control and Aging, Human Aging Research Institute and School of Life Science, Nanchang University and Jiangxi Key Laboratory of Human Aging, Nanchang, China
| | - Xiao-Li Tian
- Department of Aging and Vascular Diseases, Human Aging Research Institute and School of Life Science, Nanchang University and Jiangxi Key Laboratory of Human Aging, Nanchang, China
| | - Xin-Qiang Lan
- Department of Metabolic Control and Aging, Human Aging Research Institute and School of Life Science, Nanchang University and Jiangxi Key Laboratory of Human Aging, Nanchang, China
| | - Qi-Quan Wang
- Department of Metabolic Control and Aging, Human Aging Research Institute and School of Life Science, Nanchang University and Jiangxi Key Laboratory of Human Aging, Nanchang, China
| | - Yang Xiang
- Department of Metabolic Control and Aging, Human Aging Research Institute and School of Life Science, Nanchang University and Jiangxi Key Laboratory of Human Aging, Nanchang, China
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Hughes DC, Goodman CA, Baehr LM, Gregorevic P, Bodine SC. A critical discussion on the relationship between E3 ubiquitin ligases, protein degradation, and skeletal muscle wasting: it's not that simple. Am J Physiol Cell Physiol 2023; 325:C1567-C1582. [PMID: 37955121 PMCID: PMC10861180 DOI: 10.1152/ajpcell.00457.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 11/07/2023] [Accepted: 11/07/2023] [Indexed: 11/14/2023]
Abstract
Ubiquitination is an important post-translational modification (PTM) for protein substrates, whereby ubiquitin is added to proteins through the coordinated activity of activating (E1), ubiquitin-conjugating (E2), and ubiquitin ligase (E3) enzymes. The E3s provide key functions in the recognition of specific protein substrates to be ubiquitinated and aid in determining their proteolytic or nonproteolytic fates, which has led to their study as indicators of altered cellular processes. MuRF1 and MAFbx/Atrogin-1 were two of the first E3 ubiquitin ligases identified as being upregulated in a range of different skeletal muscle atrophy models. Since their discovery, the expression of these E3 ubiquitin ligases has often been studied as a surrogate measure of changes to bulk protein degradation rates. However, emerging evidence has highlighted the dynamic and complex regulation of the ubiquitin proteasome system (UPS) in skeletal muscle and demonstrated that protein ubiquitination is not necessarily equivalent to protein degradation. These observations highlight the potential challenges of quantifying E3 ubiquitin ligases as markers of protein degradation rates or ubiquitin proteasome system (UPS) activation. This perspective examines the usefulness of monitoring E3 ubiquitin ligases for determining specific or bulk protein degradation rates in the settings of skeletal muscle atrophy. Specific questions that remain unanswered within the skeletal muscle atrophy field are also identified, to encourage the pursuit of new research that will be critical in moving forward our understanding of the molecular mechanisms that govern protein function and degradation in muscle.
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Affiliation(s)
- David C Hughes
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States
| | - Craig A Goodman
- Centre for Muscle Research (CMR), Department of Anatomy and Physiology, The University of Melbourne, Parkville, Victoria, Australia
| | - Leslie M Baehr
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States
| | - Paul Gregorevic
- Centre for Muscle Research (CMR), Department of Anatomy and Physiology, The University of Melbourne, Parkville, Victoria, Australia
- Department of Neurology, The University of Washington School of Medicine, Seattle, Washington, United States
| | - Sue C Bodine
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States
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Cortez NE, Pathak S, Rodriguez Lanzi C, Hong BV, Crone R, Sule R, Wang F, Chen S, Gomes AV, Baar K, Mackenzie GG. A Ketogenic Diet in Combination with Gemcitabine Mitigates Pancreatic Cancer-Associated Cachexia in Male and Female KPC Mice. Int J Mol Sci 2023; 24:10753. [PMID: 37445930 PMCID: PMC10341838 DOI: 10.3390/ijms241310753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 06/20/2023] [Accepted: 06/22/2023] [Indexed: 07/15/2023] Open
Abstract
Cancer-associated cachexia (CAC) is a critical contributor to pancreatic ductal adenocarcinoma (PDAC) mortality. Thus, there is an urgent need for new strategies to mitigate PDAC-associated cachexia; and the exploration of dietary interventions is a critical component. We previously observed that a ketogenic diet (KD) combined with gemcitabine enhances overall survival in the autochthonous LSL-KrasG12D/+; LSL-Trp53 R172H/+; Pdx1-Cre (KPC) mouse model. In this study, we investigated the effect and cellular mechanisms of a KD in combination with gemcitabine on the maintenance of skeletal muscle mass in KPC mice. For this purpose, male and female pancreatic tumor-bearing KPC mice were allocated to a control diet (CD), a KD, a CD + gemcitabine (CG), or a KD + gemcitabine (KG) group. We observed that a KD or a KG-mitigated muscle strength declined over time and presented higher gastrocnemius weights compared CD-fed mice. Mechanistically, we observed sex-dependent effects of KG treatment, including the inhibition of autophagy, and increased phosphorylation levels of eIF2α in KG-treated KPC mice when compared to CG-treated mice. Our data suggest that a KG results in preservation of skeletal muscle mass. Additional research is warranted to explore whether this diet-treatment combination can be clinically effective in combating CAC in PDAC patients.
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Affiliation(s)
- Natalia E. Cortez
- Department of Nutrition, University of California, One Shields Ave., Davis, CA 95616, USA; (N.E.C.); (C.R.L.); (B.V.H.)
| | - Suraj Pathak
- Department of Physiology and Membrane Biology, One Shields Ave., Davis, CA 95616, USA; (S.P.); (R.C.); (R.S.); (A.V.G.); (K.B.)
- Department of Neurobiology, Physiology and Behavior, University of California, One Shields Ave., Davis, CA 95616, USA
| | - Cecilia Rodriguez Lanzi
- Department of Nutrition, University of California, One Shields Ave., Davis, CA 95616, USA; (N.E.C.); (C.R.L.); (B.V.H.)
| | - Brian V. Hong
- Department of Nutrition, University of California, One Shields Ave., Davis, CA 95616, USA; (N.E.C.); (C.R.L.); (B.V.H.)
| | - Ryman Crone
- Department of Physiology and Membrane Biology, One Shields Ave., Davis, CA 95616, USA; (S.P.); (R.C.); (R.S.); (A.V.G.); (K.B.)
- Department of Neurobiology, Physiology and Behavior, University of California, One Shields Ave., Davis, CA 95616, USA
| | - Rasheed Sule
- Department of Physiology and Membrane Biology, One Shields Ave., Davis, CA 95616, USA; (S.P.); (R.C.); (R.S.); (A.V.G.); (K.B.)
- Department of Neurobiology, Physiology and Behavior, University of California, One Shields Ave., Davis, CA 95616, USA
| | - Fangyi Wang
- Department of Animal Science, University of California, One Shields Ave., Davis, CA 95616, USA;
| | - Shuai Chen
- Division of Biostatistics, Department of Public Health Sciences, University of California, One Shields Ave., Davis, CA 95616, USA;
- University of California Davis Comprehensive Cancer Center, Sacramento, CA 95817, USA
| | - Aldrin V. Gomes
- Department of Physiology and Membrane Biology, One Shields Ave., Davis, CA 95616, USA; (S.P.); (R.C.); (R.S.); (A.V.G.); (K.B.)
- Department of Neurobiology, Physiology and Behavior, University of California, One Shields Ave., Davis, CA 95616, USA
| | - Keith Baar
- Department of Physiology and Membrane Biology, One Shields Ave., Davis, CA 95616, USA; (S.P.); (R.C.); (R.S.); (A.V.G.); (K.B.)
- Department of Neurobiology, Physiology and Behavior, University of California, One Shields Ave., Davis, CA 95616, USA
| | - Gerardo G. Mackenzie
- Department of Nutrition, University of California, One Shields Ave., Davis, CA 95616, USA; (N.E.C.); (C.R.L.); (B.V.H.)
- University of California Davis Comprehensive Cancer Center, Sacramento, CA 95817, USA
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Paez HG, Pitzer CR, Alway SE. Age-Related Dysfunction in Proteostasis and Cellular Quality Control in the Development of Sarcopenia. Cells 2023; 12:cells12020249. [PMID: 36672183 PMCID: PMC9856405 DOI: 10.3390/cells12020249] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 01/04/2023] [Accepted: 01/04/2023] [Indexed: 01/11/2023] Open
Abstract
Sarcopenia is a debilitating skeletal muscle disease that accelerates in the last decades of life and is characterized by marked deficits in muscle strength, mass, quality, and metabolic health. The multifactorial causes of sarcopenia have proven difficult to treat and involve a complex interplay between environmental factors and intrinsic age-associated changes. It is generally accepted that sarcopenia results in a progressive loss of skeletal muscle function that exceeds the loss of mass, indicating that while loss of muscle mass is important, loss of muscle quality is the primary defect with advanced age. Furthermore, preclinical models have suggested that aged skeletal muscle exhibits defects in cellular quality control such as the degradation of damaged mitochondria. Recent evidence suggests that a dysregulation of proteostasis, an important regulator of cellular quality control, is a significant contributor to the aging-associated declines in muscle quality, function, and mass. Although skeletal muscle mammalian target of rapamycin complex 1 (mTORC1) plays a critical role in cellular control, including skeletal muscle hypertrophy, paradoxically, sustained activation of mTORC1 recapitulates several characteristics of sarcopenia. Pharmaceutical inhibition of mTORC1 as well as caloric restriction significantly improves muscle quality in aged animals, however, the mechanisms controlling cellular proteostasis are not fully known. This information is important for developing effective therapeutic strategies that mitigate or prevent sarcopenia and associated disability. This review identifies recent and historical understanding of the molecular mechanisms of proteostasis driving age-associated muscle loss and suggests potential therapeutic interventions to slow or prevent sarcopenia.
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Affiliation(s)
- Hector G. Paez
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
- Integrated Biomedical Sciences Graduate Program, College of Graduate Health Sciences, University of Tennessee Health Science Center, Memphis, TN 38163, USA
- Laboratory of Muscle Biology and Sarcopenia, Department of Physical Therapy, College of Health Professions, University of Tennessee Health Science Center, Memphis, TN 38163, USA
- Center for Muscle, Metabolism and Neuropathology, Division of Regenerative and Rehabilitation Sciences, College of Health Professions, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Christopher R. Pitzer
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
- Integrated Biomedical Sciences Graduate Program, College of Graduate Health Sciences, University of Tennessee Health Science Center, Memphis, TN 38163, USA
- Laboratory of Muscle Biology and Sarcopenia, Department of Physical Therapy, College of Health Professions, University of Tennessee Health Science Center, Memphis, TN 38163, USA
- Center for Muscle, Metabolism and Neuropathology, Division of Regenerative and Rehabilitation Sciences, College of Health Professions, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Stephen E. Alway
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
- Integrated Biomedical Sciences Graduate Program, College of Graduate Health Sciences, University of Tennessee Health Science Center, Memphis, TN 38163, USA
- Laboratory of Muscle Biology and Sarcopenia, Department of Physical Therapy, College of Health Professions, University of Tennessee Health Science Center, Memphis, TN 38163, USA
- Center for Muscle, Metabolism and Neuropathology, Division of Regenerative and Rehabilitation Sciences, College of Health Professions, University of Tennessee Health Science Center, Memphis, TN 38163, USA
- The Tennessee Institute of Regenerative Medicine, Memphis, TN 38163, USA
- Correspondence:
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Meyer GA, Thomopoulos S, Abu-Amer Y, Shen KC. Tenotomy-induced muscle atrophy is sex-specific and independent of NFκB. eLife 2022; 11:e82016. [PMID: 36508247 PMCID: PMC9873255 DOI: 10.7554/elife.82016] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 12/09/2022] [Indexed: 12/14/2022] Open
Abstract
The nuclear factor-κB (NFκB) pathway is a major thoroughfare for skeletal muscle atrophy and is driven by diverse stimuli. Targeted inhibition of NFκB through its canonical mediator IKKβ effectively mitigates loss of muscle mass across many conditions, from denervation to unloading to cancer. In this study, we used gain- and loss-of-function mouse models to examine the role of NFκB in muscle atrophy following rotator cuff tenotomy - a model of chronic rotator cuff tear. IKKβ was knocked down or constitutively activated in muscle-specific inducible transgenic mice to elicit a twofold gain or loss of NFκB signaling. Surprisingly, neither knockdown of IKKβ nor overexpression of caIKKβ significantly altered the loss of muscle mass following tenotomy. This finding was consistent across measures of morphological adaptation (fiber cross-sectional area, fiber length, fiber number), tissue pathology (fibrosis and fatty infiltration), and intracellular signaling (ubiquitin-proteasome, autophagy). Intriguingly, late-stage tenotomy-induced atrophy was exacerbated in male mice compared with female mice. This sex specificity was driven by ongoing decreases in fiber cross-sectional area, which paralleled the accumulation of large autophagic vesicles in male, but not female muscle. These findings suggest that tenotomy-induced atrophy is not dependent on NFκB and instead may be regulated by autophagy in a sex-specific manner.
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Affiliation(s)
- Gretchen A Meyer
- Program in Physical Therapy, Washington University School of MedicineSt. LouisUnited States
- Department of Orthopaedic Surgery, Washington University School of MedicineSt LouisUnited States
- Departments of Neurology and Biomedical Engineering, Washington University School of MedicineSt. LouisUnited States
| | - Stavros Thomopoulos
- Departments of Orthopaedic Surgery and Biomedical Engineering, Columbia UniversityNew YorkUnited States
| | - Yousef Abu-Amer
- Department of Orthopaedic Surgery, Washington University School of MedicineSt LouisUnited States
- Department of Cell Biology & Physiology, Washington University School of MedicineSt. LouisUnited States
- Shriners Hospital for ChildrenSt. LouisUnited States
| | - Karen C Shen
- Program in Physical Therapy, Washington University School of MedicineSt. LouisUnited States
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Abstract
Skeletal muscle mass is a very plastic characteristic of skeletal muscle and is regulated by signaling pathways that control the balance between anabolic and catabolic processes. The serine/threonine kinase mechanistic/mammalian target of rapamycin (mTOR) has been shown to be critically important in the regulation of skeletal muscle mass through its regulation of protein synthesis and degradation pathways. In this commentary, recent advances in the understanding of the role of mTORC1 in the regulation of muscle mass under conditions that induce hypertrophy and atrophy will be highlighted.
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Affiliation(s)
- Sue C Bodine
- Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa Carver College of Medicine, 200 Hawkins Drive, Iowa City, IA 52242, USA
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Dominant-negative p53-overexpression in skeletal muscle induces cell death and fiber atrophy in rats. Cell Death Dis 2022; 13:716. [PMID: 35977948 PMCID: PMC9385859 DOI: 10.1038/s41419-022-05160-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Revised: 08/01/2022] [Accepted: 08/03/2022] [Indexed: 01/21/2023]
Abstract
The tumor suppressor p53 is thought to play a key role in the maintenance of cell size and homeostasis, but relatively little is known about its role in skeletal muscle. Based on its ability to suppress cell growth, we hypothesized that inhibiting the function of wild-type p53 through the overexpression of a dominant-negative p53 mutant (DDp53) could result in muscle fiber hypertrophy. To test this hypothesis, we electroporated adult rat tibialis anterior muscles with DDp53 and collected the tissue three weeks later. We confirmed successful overexpression of DDp53 on a histological and biochemical level and found pronounced changes to muscle architecture, metabolism, and molecular signaling. Muscle mass, fiber cross-sectional area, and fiber diameter significantly decreased with DDp53 overexpression. We found histopathological changes in DDp53 transfected muscle which were accompanied by increased levels of proteins that are associated with membrane damage and repair. In addition, DDp53 decreased oxidative phosphorylation complex I and V protein levels, and despite its negative effects on muscle mass and fiber size, caused an increase in muscle protein synthesis as assessed via the SUnSET technique. Interestingly, the increase in muscle protein synthesis was concomitant with a decrease in phospho-S6K1 (Thr389). Furthermore, the muscle wasting in the DDp53 electroporated leg was accompanied by a decrease in global protein ubiquitination and an increase in proteasome activity. In conclusion, overexpression of a dominant-negative p53 mutant in skeletal muscle results in decreased muscle mass, myofiber size, histological muscle damage, a metabolic phenotype, and perturbed homeostasis between muscle protein synthesis and degradation.
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Removal of MuRF1 Increases Muscle Mass in Nemaline Myopathy Models, but Does Not Provide Functional Benefits. Int J Mol Sci 2022; 23:ijms23158113. [PMID: 35897687 PMCID: PMC9331820 DOI: 10.3390/ijms23158113] [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: 05/13/2022] [Revised: 07/18/2022] [Accepted: 07/20/2022] [Indexed: 11/16/2022] Open
Abstract
Nemaline myopathy (NM) is characterized by skeletal muscle weakness and atrophy. No curative treatments exist for this debilitating disease. NM is caused by mutations in proteins involved in thin-filament function, turnover, and maintenance. Mutations in nebulin, encoded by NEB, are the most common cause. Skeletal muscle atrophy is tightly linked to upregulation of MuRF1, an E3 ligase, that targets proteins for proteasome degradation. Here, we report a large increase in MuRF1 protein levels in both patients with nebulin-based NM, also named NEM2, and in mouse models of the disease. We hypothesized that knocking out MuRF1 in animal models of NM with muscle atrophy would ameliorate the muscle deficits. To test this, we crossed MuRF1 KO mice with two NEM2 mouse models, one with the typical form and the other with the severe form. The crosses were viable, and muscles were studied in mice at 3 months of life. Ultrastructural examination of gastrocnemius muscle lacking MuRF1 and with severe NM revealed a small increase in vacuoles, but no significant change in the myofibrillar fractional area. MuRF1 deficiency led to increased weights of various muscle types in the NM models. However, this increase in muscle size was not associated with increased in vivo or in vitro force production. We conclude that knocking out MuRF1 in NEM2 mice increases muscle size, but does not improve muscle function.
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11
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Nassar R, Vernus B, Carnac G, Fouret G, Goustard B, Casas F, Tintignac L, Cassar-Malek I, Picard B, Seiliez I, Brioche T, Koechlin-Ramonatxo C, Bertrand-Gaday C, Hamade A, Najjar F, Chabi B, Bonnieu A. Myostatin gene inactivation increases post-mortem calpain-dependent muscle proteolysis in mice. Meat Sci 2021; 185:108726. [PMID: 34973590 DOI: 10.1016/j.meatsci.2021.108726] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 12/17/2021] [Accepted: 12/19/2021] [Indexed: 12/13/2022]
Abstract
Myostatin deficiency leads to extensive skeletal muscle hypertrophy, but its consequence on post-mortem muscle proteolysis is unknown. Here, we compared muscle myofibrillar protein degradation, and autophagy, ubiquitin-proteasome and Ca2+-dependent proteolysis relative to the energetic and redox status in wild-type (WT) and myostatin knock-out mice (KO) during early post-mortem storage. KO muscles showed higher degradation of myofibrillar proteins in the first 24 h after death, associated with preserved antioxidant status, compared with WT muscles. Analysis of key autophagy and ubiquitin-proteasome system markers indicated that these two pathways were not upregulated in post-mortem muscle (both genotypes), but basal autophagic flux and ATP content were lower in KO muscles. Proteasome and caspase activities were not different between WT and KO mice. Conversely, calpain activity was higher in KO muscles, concomitantly with higher troponin T and desmin degradation. Altogether, these results suggest that calpains but not the autophagy, proteasome and caspase systems, explain the difference in post-mortem muscle protein proteolysis between both genotypes.
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Affiliation(s)
- Rim Nassar
- DMEM, University of Montpellier, INRAE, Montpellier, France; Laboratoire d'Innovation thérapeutique, Lebanese University, Beyrouth, Liban
| | - Barbara Vernus
- DMEM, University of Montpellier, INRAE, Montpellier, France
| | - Gilles Carnac
- PHYMEDEXP, University of Montpellier, CNRS, INSERM, CHRU, Montpellier, France
| | - Gilles Fouret
- DMEM, University of Montpellier, INRAE, Montpellier, France
| | | | - François Casas
- DMEM, University of Montpellier, INRAE, Montpellier, France
| | - Lionel Tintignac
- Département de Biomédecine, Basel University, Basel, Switzerland
| | - Isabelle Cassar-Malek
- University Clermont Auvergne, INRAE, VetAgro Sup, UMR Herbivores, F-63122 Saint-Genès-Champanelle, France
| | - Brigitte Picard
- University Clermont Auvergne, INRAE, VetAgro Sup, UMR Herbivores, F-63122 Saint-Genès-Champanelle, France
| | - Iban Seiliez
- Université de Pau et des Pays de l'Adour, E2S UPPA, INRAE, UMR1419 Nutrition Métabolisme et Aquaculture, F-64310 Saint-Pée-sur-Nivelle, France
| | - Thomas Brioche
- DMEM, University of Montpellier, INRAE, Montpellier, France
| | | | | | - Aline Hamade
- Laboratoire d'Innovation thérapeutique, Lebanese University, Beyrouth, Liban
| | - Fadia Najjar
- Laboratoire d'Innovation thérapeutique, Lebanese University, Beyrouth, Liban
| | - Béatrice Chabi
- DMEM, University of Montpellier, INRAE, Montpellier, France
| | - Anne Bonnieu
- DMEM, University of Montpellier, INRAE, Montpellier, France.
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12
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Kobak KA, Lawrence MM, Pharaoh G, Borowik AK, Peelor FF, Shipman PD, Griffin TM, Van Remmen H, Miller BF. Determining the contributions of protein synthesis and breakdown to muscle atrophy requires non-steady-state equations. J Cachexia Sarcopenia Muscle 2021; 12:1764-1775. [PMID: 34418329 PMCID: PMC8718081 DOI: 10.1002/jcsm.12772] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 06/17/2021] [Accepted: 07/10/2021] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND Ageing and cachexia cause a loss of muscle mass over time, indicating that protein breakdown exceeds protein synthesis. Deuterium oxide (D2 O) is used for studies of protein turnover because of the advantages of long-term labelling, but these methods introduce considerations that have been largely overlooked when studying conditions of protein gain or loss. The purpose of this study was to demonstrate the importance of accounting for a change in protein mass, a non-steady state, during D2 O labelling studies while also exploring the contribution of protein synthesis and breakdown to denervation-induced muscle atrophy. METHODS Adult (6 months) male C57BL/6 mice (n = 14) were labelled with D2 O for a total of 7 days following unilateral sciatic nerve transection to induce denervation of hindlimb muscles. The contralateral sham limb and nonsurgical mice (n = 5) were used as two different controls to account for potential crossover effects of denervation. We calculated gastrocnemius myofibrillar and collagen protein synthesis and breakdown assuming steady-state or using non-steady-state modelling. We measured RNA synthesis rates to further understand ribosomal turnover during atrophy. RESULTS Gastrocnemius mass was less in denervated muscle (137 ± 9 mg) compared with sham (174 ± 15 mg; P < 0.0001) or nonsurgical control (162 ± 5 mg; P < 0.0001). With steady-state calculations, fractional synthesis and breakdown rates (FSR and FBR) were lower in the denervated muscle (1.49 ± 0.06%/day) compared with sham (1.81 ± 0.09%/day; P < 0.0001) or nonsurgical control (2.27 ± 0.04%/day; P < 0.0001). When adjusting for change in protein mass, FSR was 4.21 ± 0.19%/day in denervated limb, whereas FBR was 4.09 ± 0.22%/day. When considering change in protein mass (ksyn ), myofibrillar synthesis was lower in denervated limb (2.44 ± 0.14 mg/day) compared with sham (3.43 ± 0.22 mg/day; P < 0.0001) and non-surgical control (3.74 ± 0.12 mg/day; P < 0.0001), whereas rate of protein breakdown (kdeg, 1/t) was greater in denervated limb (0.050 ± 0.003) compared with sham (0.019 ± 0.001; P < 0.0001) and nonsurgical control (0.023 ± 0.000; P < 0.0001). Muscle collagen breakdown was completely inhibited during denervation. There was a strong correlation (r = 0.83, P < 0.001) between RNA and myofibrillar protein synthesis in sham but not denervated muscle. CONCLUSIONS We show conflicting results between steady- and non-steady-state calculations on myofibrillar protein synthesis and breakdown during periods of muscle loss. We also found that collagen accumulation was largely from a decrease in collagen breakdown. Comparison between sham and non-surgical control demonstrated a crossover effect of denervation on myofibrillar protein synthesis and ribosomal biogenesis, which impacts study design for unilateral atrophy studies. These considerations are important because not accounting for them can mislead therapeutic attempts to maintain muscle mass.
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Affiliation(s)
- Kamil A Kobak
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA.,Laboratory for Applied Research on Cardiovascular System, Department of Heart Diseases, Wroclaw Medical University, Wroclaw, Poland
| | - Marcus M Lawrence
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA.,Department of Kinesiology and Outdoor Recreation, Southern Utah University, Cedar City, UT, USA
| | - Gavin Pharaoh
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Agnieszka K Borowik
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Frederick F Peelor
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Patrick D Shipman
- Department of Mathematics, Colorado State University, Fort Collins, CO, USA
| | - Timothy M Griffin
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA.,Oklahoma City VA Medical Center, Oklahoma City, OK, USA
| | - Holly Van Remmen
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA.,Oklahoma City VA Medical Center, Oklahoma City, OK, USA
| | - Benjamin F Miller
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
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13
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Preliminary Observations on Skeletal Muscle Adaptation and Plasticity in Homer 2 -/- Mice. Metabolites 2021; 11:metabo11090642. [PMID: 34564458 PMCID: PMC8469648 DOI: 10.3390/metabo11090642] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 09/16/2021] [Accepted: 09/18/2021] [Indexed: 01/05/2023] Open
Abstract
Homer represents a diversified family of scaffold and transduction proteins made up of several isoforms. Here, we present preliminary observations on skeletal muscle adaptation and plasticity in a transgenic model of Homer 2-/- mouse using a multifaceted approach entailing morphometry, quantitative RT-PCR (Reverse Transcription PCR), confocal immunofluorescence, and electrophysiology. Morphometry shows that Soleus muscle (SOL), at variance with Extensor digitorum longus muscle (EDL) and Flexor digitorum brevis muscle (FDB), displays sizable reduction of fibre cross-sectional area compared to the WT counterparts. In SOL of Homer 2-/- mice, quantitative RT-PCR indicated the upregulation of Atrogin-1 and Muscle ring finger protein 1 (MuRF1) genes, and confocal immunofluorescence showed the decrease of neuromuscular junction (NMJ) Homer content. Electrophysiological measurements of isolated FDB fibres from Homer 2-/- mice detected the exclusive presence of the adult ε-nAChR isoform excluding denervation. As for NMJ morphology, data were not conclusive, and further work is needed to ascertain whether the null Homer 2 phenotype induces any endplate remodelling. Within the context of adaptation and plasticity, the present data show that Homer 2 is a co-regulator of the normotrophic status in a muscle specific fashion.
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14
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Anderson LB, Ravara B, Hameed S, Latour CD, Latour SM, Graham VM, Hashmi MN, Cobb B, Dethrow N, Urazaev AK, Davie JK, Albertin G, Carraro U, Zampieri S, Pond AL. MERG1A Protein Abundance Increases in the Atrophied Skeletal Muscle of Denervated Mice, But Does Not Affect NFκB Activity. J Neuropathol Exp Neurol 2021; 80:776-788. [PMID: 34363662 DOI: 10.1093/jnen/nlab062] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Skeletal muscle atrophy may occur with disease, injury, decreased muscle use, starvation, and normal aging. No reliably effective treatments for atrophy are available, thus research into the mechanisms contributing to muscle loss is essential. The ERG1A K+ channel contributes to muscle loss by increasing ubiquitin proteasome proteolysis (UPP) in the skeletal muscle of both unweighted and cachectic mice. Because the mechanisms which produce atrophy vary based upon the initiating factor, here we investigate atrophy produced by denervation. Using immunohistochemistry and immunoblots, we demonstrate that ERG1A protein abundance increases significantly in the Gastrocnemius muscle of rodents 7 days after both sciatic nerve transection and hind limb unweighting. Further, we reveal that ectopic expression of a Merg1a encoded plasmid in normal mouse Gastrocnemius muscle has no effect on activity of the NFκB transcription factor family, a group of proteins which contribute to muscle atrophy by modulation of the UPP. Further, although NFκB activity increases significantly after denervation, we show that expression of a plasmid encoding a dominant negative Merg1a mutant in Gastrocnemius muscle prior to denervation, has no effect on NFκB activity. Thus, although the ERG1A K+ channel increases UPP, it does not do so through modulation of NFκB transcription factors.
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Affiliation(s)
- Luke B Anderson
- Anatomy Department, Southern Illinois University, Carbondale, Illinois, USA (LBA, SH, MNH, BC, ND, ALP)
| | - Barbara Ravara
- Department of Surgery, Oncology, and Gastroenterology and Department of Biomedical Sciences, University of Padova, Padova, Italy (BR, GA, SZ).,Department of Neuroscience (DNS), University of Padova, Padova, Italy (BR, GA).,A&C M-C Foundation for Translational Myology, Padova, Italy (BR, UC)
| | - Sohaib Hameed
- Anatomy Department, Southern Illinois University, Carbondale, Illinois, USA (LBA, SH, MNH, BC, ND, ALP)
| | - Chase D Latour
- Gillings School of Public Health, University of North Carolina, Chapel Hill, North Carolina, USA (CDL)
| | - Sawyer M Latour
- Doisey School of Health, Saint Louis University, St. Louis, Missouri, USA (SML, VMG)
| | - Valerie M Graham
- Doisey School of Health, Saint Louis University, St. Louis, Missouri, USA (SML, VMG)
| | - Mariam N Hashmi
- Anatomy Department, Southern Illinois University, Carbondale, Illinois, USA (LBA, SH, MNH, BC, ND, ALP)
| | - Brittan Cobb
- Anatomy Department, Southern Illinois University, Carbondale, Illinois, USA (LBA, SH, MNH, BC, ND, ALP)
| | - Nicole Dethrow
- Anatomy Department, Southern Illinois University, Carbondale, Illinois, USA (LBA, SH, MNH, BC, ND, ALP)
| | - Albert K Urazaev
- School of Arts, Sciences and Education, Ivy Technical Community College, Lafayette, Indiana, USA (AKU)
| | - Judy K Davie
- Biochemistry Department, Southern Illinois University, Carbondale, Illinois, USA(JKD)
| | - Giovanna Albertin
- Department of Surgery, Oncology, and Gastroenterology and Department of Biomedical Sciences, University of Padova, Padova, Italy (BR, GA, SZ).,Department of Neuroscience (DNS), University of Padova, Padova, Italy (BR, GA)
| | - Ugo Carraro
- A&C M-C Foundation for Translational Myology, Padova, Italy (BR, UC)
| | - Sandra Zampieri
- Department of Surgery, Oncology, and Gastroenterology and Department of Biomedical Sciences, University of Padova, Padova, Italy (BR, GA, SZ)
| | - Amber L Pond
- Anatomy Department, Southern Illinois University, Carbondale, Illinois, USA (LBA, SH, MNH, BC, ND, ALP)
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15
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Nishimura Y, Musa I, Holm L, Lai YC. Recent advances in measuring and understanding the regulation of exercise-mediated protein degradation in skeletal muscle. Am J Physiol Cell Physiol 2021; 321:C276-C287. [PMID: 34038244 DOI: 10.1152/ajpcell.00115.2021] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Skeletal muscle protein turnover plays a crucial role in controlling muscle mass and protein quality control, including sarcomeric (structural and contractile) proteins. Protein turnover is a dynamic and continual process of protein synthesis and degradation. The ubiquitin proteasome system (UPS) is a key degradative system for protein degradation and protein quality control in skeletal muscle. UPS-mediated protein quality control is known to be impaired in aging and diseases. Exercise is a well-recognized, nonpharmacological approach to promote muscle protein turnover rates. Over the past decades, we have acquired substantial knowledge of molecular mechanisms of muscle protein synthesis after exercise. However, there have been considerable gaps in the mechanisms of how muscle protein degradation is regulated at the molecular level. The main challenge to understand muscle protein degradation is due in part to the lack of solid stable isotope tracer methodology to measure muscle protein degradation rate. Understanding the mechanisms of UPS with the concomitant measurement of protein degradation rate in skeletal muscle will help identify novel therapeutic strategies to ameliorate impaired protein turnover and protein quality control in aging and diseases. Thus, the goal of this present review was to highlight how recent advances in the field may help improve our understanding of exercise-mediated protein degradation. We discuss 1) the emerging roles of protein phosphorylation and ubiquitylation modifications in regulating proteasome-mediated protein degradation after exercise and 2) methodological advances to measure in vivo myofibrillar protein degradation rate using stable isotope tracer methods.
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Affiliation(s)
- Yusuke Nishimura
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Ibrahim Musa
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Lars Holm
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research, University of Birmingham, Birmingham, United Kingdom
| | - Yu-Chiang Lai
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research, University of Birmingham, Birmingham, United Kingdom
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
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16
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Baehr LM, Hughes DC, Lynch SA, Van Haver D, Maia TM, Marshall AG, Radoshevich L, Impens F, Waddell DS, Bodine SC. Identification of the MuRF1 Skeletal Muscle Ubiquitylome Through Quantitative Proteomics. FUNCTION (OXFORD, ENGLAND) 2021; 2:zqab029. [PMID: 34179788 PMCID: PMC8218097 DOI: 10.1093/function/zqab029] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 05/12/2021] [Accepted: 05/17/2021] [Indexed: 02/07/2023]
Abstract
MuRF1 (TRIM63) is a muscle-specific E3 ubiquitin ligase and component of the ubiquitin proteasome system. MuRF1 is transcriptionally upregulated under conditions that cause muscle loss, in both rodents and humans, and is a recognized marker of muscle atrophy. In this study, we used in vivo electroporation to determine whether MuRF1 overexpression alone can cause muscle atrophy and, in combination with ubiquitin proteomics, identify the endogenous MuRF1 substrates in skeletal muscle. Overexpression of MuRF1 in adult mice increases ubiquitination of myofibrillar and sarcoplasmic proteins, increases expression of genes associated with neuromuscular junction instability, and causes muscle atrophy. A total of 169 ubiquitination sites on 56 proteins were found to be regulated by MuRF1. MuRF1-mediated ubiquitination targeted both thick and thin filament contractile proteins, as well as, glycolytic enzymes, deubiquitinases, p62, and VCP. These data reveal a potential role for MuRF1 in not only the breakdown of the sarcomere but also the regulation of metabolism and other proteolytic pathways in skeletal muscle.
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Affiliation(s)
| | | | - Sarah A Lynch
- Department of Biology, University of North Florida, 1 UNF Drive, Jacksonville, FL 32224, USA
| | - Delphi Van Haver
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium,VIB Center for Medical Biotechnology, Ghent, Belgium,VIB Proteomics Core, Ghent, Belgium
| | - Teresa Mendes Maia
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium,VIB Center for Medical Biotechnology, Ghent, Belgium,VIB Proteomics Core, Ghent, Belgium
| | - Andrea G Marshall
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Lilliana Radoshevich
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Francis Impens
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium,VIB Center for Medical Biotechnology, Ghent, Belgium,VIB Proteomics Core, Ghent, Belgium
| | - David S Waddell
- Department of Biology, University of North Florida, 1 UNF Drive, Jacksonville, FL 32224, USA
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17
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Davidyan A, Pathak S, Baar K, Bodine SC. Maintenance of muscle mass in adult male mice is independent of testosterone. PLoS One 2021; 16:e0240278. [PMID: 33764986 PMCID: PMC7993603 DOI: 10.1371/journal.pone.0240278] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 02/12/2021] [Indexed: 01/21/2023] Open
Abstract
Testosterone is considered a potent anabolic agent in skeletal muscle with a well-established role in adolescent growth and development in males. However, the role of testosterone in the regulation of skeletal muscle mass and function throughout the lifespan has yet to be fully established. While some studies suggest that testosterone is important for the maintenance of skeletal muscle mass, an understanding of the role this hormone plays in young, adult, and old males with normal and low serum testosterone levels is lacking. We investigated the role testosterone plays in the maintenance of muscle mass by examining the effect of orchiectomy-induced testosterone depletion in C57Bl6 male mice at ages ranging from early postnatal through old age (1.5-, 5-, 12-, and 24-month old mice). Following 28 days of testosterone depletion, we assessed mass and fiber cross-sectional-area (CSA) of the tibialis anterior, gastrocnemius, and quadriceps muscles. In addition, we measured global rates of protein synthesis and degradation using the SuNSET method, western blots, and enzyme activity assays. Twenty-eight days of testosterone depletion resulted in reduced muscle mass in the two youngest cohorts, but had no effect in the two oldest cohorts. Mean CSA decreased only in the youngest cohort and only in the tibialis anterior muscle. Testosterone depletion resulted in a general increase in proteasome activity at all ages. No change in protein synthesis was detected at the terminal time point. These data suggest that within physiological serum concentrations, testosterone may not be critical for the maintenance of muscle mass in mature male mice; however, in young mice testosterone is crucial for normal growth.
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Affiliation(s)
- Arik Davidyan
- Department of Neurobiology, Physiology and Behavior, University of California Davis, Davis, CA, United States of America
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, United States of America
| | - Suraj Pathak
- Department of Neurobiology, Physiology and Behavior, University of California Davis, Davis, CA, United States of America
| | - Keith Baar
- Department of Neurobiology, Physiology and Behavior, University of California Davis, Davis, CA, United States of America
- Department of Physiology and Membrane Biology University of California Davis, Davis, CA, United States of America
| | - Sue C. Bodine
- Department of Internal Medicine, University of Iowa, Iowa City, IA, United States of America
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18
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Smuder AJ, Turner SM, Schuster CM, Morton AB, Hinkley JM, Fuller DD. Hyperbaric Oxygen Treatment Following Mid-Cervical Spinal Cord Injury Preserves Diaphragm Muscle Function. Int J Mol Sci 2020; 21:ijms21197219. [PMID: 33007822 PMCID: PMC7582297 DOI: 10.3390/ijms21197219] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 09/24/2020] [Accepted: 09/27/2020] [Indexed: 12/17/2022] Open
Abstract
Oxidative damage to the diaphragm as a result of cervical spinal cord injury (SCI) promotes muscle atrophy and weakness. Respiratory insufficiency is the leading cause of morbidity and mortality in cervical spinal cord injury (SCI) patients, emphasizing the need for strategies to maintain diaphragm function. Hyperbaric oxygen (HBO) increases the amount of oxygen dissolved into the blood, elevating the delivery of oxygen to skeletal muscle and reactive oxygen species (ROS) generation. It is proposed that enhanced ROS production due to HBO treatment stimulates adaptations to diaphragm oxidative capacity, resulting in overall reductions in oxidative stress and inflammation. Therefore, we tested the hypothesis that exposure to HBO therapy acutely following SCI would reduce oxidative damage to the diaphragm muscle, preserving muscle fiber size and contractility. Our results demonstrated that lateral contusion injury at C3/4 results in a significant reduction in diaphragm muscle-specific force production and fiber cross-sectional area, which was associated with augmented mitochondrial hydrogen peroxide emission and a reduced mitochondrial respiratory control ratio. In contrast, rats that underwent SCI followed by HBO exposure consisting of 1 h of 100% oxygen at 3 atmospheres absolute (ATA) delivered for 10 consecutive days demonstrated an improvement in diaphragm-specific force production, and an attenuation of fiber atrophy, mitochondrial dysfunction and ROS production. These beneficial adaptations in the diaphragm were related to HBO-induced increases in antioxidant capacity and a reduction in atrogene expression. These findings suggest that HBO therapy may be an effective adjunctive therapy to promote respiratory health following cervical SCI.
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Affiliation(s)
- Ashley J. Smuder
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL 32611, USA; (A.B.M.); (J.M.H.)
- Breathing Research and Therapeutics, University of Florida, Gainesville, FL 32610, USA;
- Correspondence:
| | - Sara M. Turner
- Department of Physical Therapy, University of Florida, Gainesville, FL 32610, USA; (S.M.T.); (C.M.S.)
| | - Cassandra M. Schuster
- Department of Physical Therapy, University of Florida, Gainesville, FL 32610, USA; (S.M.T.); (C.M.S.)
| | - Aaron B. Morton
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL 32611, USA; (A.B.M.); (J.M.H.)
| | - J. Matthew Hinkley
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL 32611, USA; (A.B.M.); (J.M.H.)
| | - David D. Fuller
- Breathing Research and Therapeutics, University of Florida, Gainesville, FL 32610, USA;
- Department of Physical Therapy, University of Florida, Gainesville, FL 32610, USA; (S.M.T.); (C.M.S.)
- McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
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19
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Mechanical loading of tissue engineered skeletal muscle prevents dexamethasone induced myotube atrophy. J Muscle Res Cell Motil 2020; 42:149-159. [PMID: 32955689 PMCID: PMC8332579 DOI: 10.1007/s10974-020-09589-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 09/04/2020] [Indexed: 12/21/2022]
Abstract
Skeletal muscle atrophy as a consequence of acute and chronic illness, immobilisation, muscular dystrophies and aging, leads to severe muscle weakness, inactivity and increased mortality. Mechanical loading is thought to be the primary driver for skeletal muscle hypertrophy, however the extent to which mechanical loading can offset muscle catabolism has not been thoroughly explored. In vitro 3D-models of skeletal muscle provide a controllable, high throughput environment and mitigating many of the ethical and methodological constraints present during in vivo experimentation. This work aimed to determine if mechanical loading would offset dexamethasone (DEX) induced skeletal muscle atrophy, in muscle engineered using the C2C12 murine cell line. Mechanical loading successfully offset myotube atrophy and functional degeneration associated with DEX regardless of whether the loading occurred before or after 24 h of DEX treatment. Furthermore, mechanical load prevented increases in MuRF-1 and MAFbx mRNA expression, critical regulators of muscle atrophy. Overall, we demonstrate the application of tissue engineered muscle to study skeletal muscle health and disease, offering great potential for future use to better understand treatment modalities for skeletal muscle atrophy.
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20
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Docosahexaenoic Acid, a Potential Treatment for Sarcopenia, Modulates the Ubiquitin-Proteasome and the Autophagy-Lysosome Systems. Nutrients 2020; 12:nu12092597. [PMID: 32859116 PMCID: PMC7551806 DOI: 10.3390/nu12092597] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 08/22/2020] [Accepted: 08/24/2020] [Indexed: 12/14/2022] Open
Abstract
One of the characteristic features of aging is the progressive loss of muscle mass, a nosological syndrome called sarcopenia. It is also a pathologic risk factor for many clinically adverse outcomes in older adults. Therefore, delaying the loss of muscle mass, through either boosting muscle protein synthesis or slowing down muscle protein degradation using nutritional supplements could be a compelling strategy to address the needs of the world’s aging population. Here, we review the recently identified properties of docosahexaenoic acid (DHA). It was shown to delay muscle wasting by stimulating intermediate oxidative stress and inhibiting proteasomal degradation of muscle proteins. Both the ubiquitin–proteasome and the autophagy–lysosome systems are modulated by DHA. Collectively, growing evidence indicates that DHA is a potent pharmacological agent that could improve muscle homeostasis. Better understanding of cellular proteolytic systems associated with sarcopenia will allow us to identify novel therapeutic interventions, such as omega-3 polyunsaturated fatty acids, to treat this disease.
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Hughes DC, Baehr LM, Driscoll JR, Lynch SA, Waddell DS, Bodine SC. Identification and characterization of Fbxl22, a novel skeletal muscle atrophy-promoting E3 ubiquitin ligase. Am J Physiol Cell Physiol 2020; 319:C700-C719. [PMID: 32783651 DOI: 10.1152/ajpcell.00253.2020] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Muscle-specific E3 ubiquitin ligases have been identified in muscle atrophy-inducing conditions. The purpose of the current study was to explore the functional role of F-box and leucine-rich protein 22 (Fbxl22), and a newly identified splice variant (Fbxl22-193), in skeletal muscle homeostasis and neurogenic muscle atrophy. In mouse C2C12 muscle cells, promoter fragments of the Fbxl22 gene were cloned and fused with the secreted alkaline phosphatase reporter gene to assess the transcriptional regulation of Fbxl22. The tibialis anterior muscles of male C57/BL6 mice (12-16 wk old) were electroporated with expression plasmids containing the cDNA of two Fbxl22 splice variants and tissues collected after 7, 14, and 28 days. Gastrocnemius muscles of wild-type and muscle-specific RING finger 1 knockout (MuRF1 KO) mice were electroporated with an Fbxl22 RNAi or empty plasmid and denervated 3 days posttransfection, and tissues were collected 7 days postdenervation. The full-length gene and novel splice variant are transcriptionally induced early (after 3 days) during neurogenic muscle atrophy. In vivo overexpression of Fbxl22 isoforms in mouse skeletal muscle leads to evidence of myopathy/atrophy, suggesting that both are involved in the process of neurogenic muscle atrophy. Knockdown of Fbxl22 in the muscles of MuRF1 KO mice resulted in significant additive muscle sparing 7 days after denervation. Targeting two E3 ubiquitin ligases appears to have a strong additive effect on protecting muscle mass loss with denervation, and these findings have important implications in the development of therapeutic strategies to treat muscle atrophy.
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Affiliation(s)
- David C Hughes
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Leslie M Baehr
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Julia R Driscoll
- Department of Biology, University of North Florida, Jacksonville, Florida
| | - Sarah A Lynch
- Department of Biology, University of North Florida, Jacksonville, Florida
| | - David S Waddell
- Department of Biology, University of North Florida, Jacksonville, Florida
| | - Sue C Bodine
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa
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22
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Bodine SC. Edward F. Adolph Distinguished Lecture. Skeletal muscle atrophy: Multiple pathways leading to a common outcome. J Appl Physiol (1985) 2020; 129:272-282. [PMID: 32644910 DOI: 10.1152/japplphysiol.00381.2020] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Skeletal muscle atrophy continues to be a serious consequence of many diseases and conditions for which there is no treatment. Our understanding of the mechanisms regulating skeletal muscle mass has improved considerably over the past two decades. For many years it was known that skeletal muscle atrophy resulted from an imbalance between protein synthesis and protein breakdown, with the net balance shifting toward protein breakdown. However, the molecular and cellular mechanisms underlying the increased breakdown of myofibrils was unknown. Over the past two decades, numerous reports have identified novel genes and signaling pathways that are upregulated and activated in response to stimuli such as disuse, inflammation, metabolic stress, starvation and others that induce muscle atrophy. This review summarizes the discovery efforts performed in the identification of several pathways involved in the regulation of skeletal muscle mass: the mammalian target of rapamycin (mTORC1) and the ubiquitin proteasome pathway and the E3 ligases, MuRF1 and MAFbx. While muscle atrophy is a common outcome of many diseases, it is doubtful that a single gene or pathway initiates or mediates the breakdown of myofibrils. Interestingly, however, is the observation that upregulation of the E3 ligases, MuRF1 and MAFbx, is a common feature of many divergent atrophy conditions. The challenge for the field of muscle biology is to understand how all of the various molecules, transcription factors, and signaling pathways interact to produce muscle atrophy and to identify the critical factors for intervention.
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Affiliation(s)
- Sue C Bodine
- Department of Internal Medicine/Endocrinology and Metabolism, University of Iowa Carver College of Medicine, Iowa City, Iowa
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23
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Vainshtein A, Sandri M. Signaling Pathways That Control Muscle Mass. Int J Mol Sci 2020; 21:ijms21134759. [PMID: 32635462 PMCID: PMC7369702 DOI: 10.3390/ijms21134759] [Citation(s) in RCA: 94] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 06/23/2020] [Accepted: 07/01/2020] [Indexed: 12/12/2022] Open
Abstract
The loss of skeletal muscle mass under a wide range of acute and chronic maladies is associated with poor prognosis, reduced quality of life, and increased mortality. Decades of research indicate the importance of skeletal muscle for whole body metabolism, glucose homeostasis, as well as overall health and wellbeing. This tissue’s remarkable ability to rapidly and effectively adapt to changing environmental cues is a double-edged sword. Physiological adaptations that are beneficial throughout life become maladaptive during atrophic conditions. The atrophic program can be activated by mechanical, oxidative, and energetic distress, and is influenced by the availability of nutrients, growth factors, and cytokines. Largely governed by a transcription-dependent mechanism, this program impinges on multiple protein networks including various organelles as well as biosynthetic and quality control systems. Although modulating muscle function to prevent and treat disease is an enticing concept that has intrigued research teams for decades, a lack of thorough understanding of the molecular mechanisms and signaling pathways that control muscle mass, in addition to poor transferability of findings from rodents to humans, has obstructed efforts to develop effective treatments. Here, we review the progress made in unraveling the molecular mechanisms responsible for the regulation of muscle mass, as this continues to be an intensive area of research.
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Affiliation(s)
| | - Marco Sandri
- Veneto Institute of Molecular Medicine, via Orus 2, 35129 Padua, Italy
- Department of Biomedical Science, University of Padua, via G. Colombo 3, 35100 Padua, Italy
- Myology Center, University of Padua, via G. Colombo 3, 35100 Padova, Italy
- Department of Medicine, McGill University, Montreal, QC H3A 0G4, Canada
- Correspondence:
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Nguyen T, Bowen TS, Augstein A, Schauer A, Gasch A, Linke A, Labeit S, Adams V. Expression of MuRF1 or MuRF2 is essential for the induction of skeletal muscle atrophy and dysfunction in a murine pulmonary hypertension model. Skelet Muscle 2020; 10:12. [PMID: 32340625 PMCID: PMC7184701 DOI: 10.1186/s13395-020-00229-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 04/13/2020] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Pulmonary hypertension leads to right ventricular heart failure and ultimately to cardiac cachexia. Cardiac cachexia induces skeletal muscles atrophy and contractile dysfunction. MAFbx and MuRF1 are two key proteins that have been implicated in chronic muscle atrophy of several wasting states. METHODS Monocrotaline (MCT) was injected over eight weeks into mice to establish pulmonary hypertension as a murine model for cardiac cachexia. The effects on skeletal muscle atrophy, myofiber force, and selected muscle proteins were evaluated in wild-type (WT), MuRF1, and MuRF2-KO mice by determining muscle weights, in vitro muscle force and enzyme activities in soleus and tibialis anterior (TA) muscle. RESULTS In WT, MCT treatment induced wasting of soleus and TA mass, loss of myofiber force, and depletion of citrate synthase (CS), creatine kinase (CK), and malate dehydrogenase (MDH) (all key metabolic enzymes). This suggests that the murine MCT model is useful to mimic peripheral myopathies as found in human cardiac cachexia. In MuRF1 and MuRF2-KO mice, soleus and TA muscles were protected from atrophy, contractile dysfunction, while metabolic enzymes were not lowered in MuRF1 or MuRF2-KO mice. Furthermore, MuRF2 expression was lower in MuRF1KO mice when compared to C57BL/6 mice. CONCLUSIONS In addition to MuRF1, inactivation of MuRF2 also provides a potent protection from peripheral myopathy in cardiac cachexia. The protection of metabolic enzymes in both MuRF1KO and MuRF2KO mice as well as the dependence of MuRF2 expression on MuRF1 suggests intimate relationships between MuRF1 and MuRF2 during muscle atrophy signaling.
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Affiliation(s)
- Thanh Nguyen
- University Clinic of Cardiology, Heart Center Leipzig, Leipzig, Germany
| | - T Scott Bowen
- School of Biomedical Sciences, University of Leeds, Leeds, UK
| | - Antje Augstein
- Laboratory of Molecular and Experimental Cardiology, TU Dresden, Heart Center Dresden, Dresden, Germany
| | - Antje Schauer
- Laboratory of Molecular and Experimental Cardiology, TU Dresden, Heart Center Dresden, Dresden, Germany
| | - Alexander Gasch
- Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Axel Linke
- Laboratory of Molecular and Experimental Cardiology, TU Dresden, Heart Center Dresden, Dresden, Germany
| | - Siegfried Labeit
- Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany.,Myomedix GmbH, Neckargemünd, Germany
| | - Volker Adams
- Laboratory of Molecular and Experimental Cardiology, TU Dresden, Heart Center Dresden, Dresden, Germany.
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Cooper LM, Hanson A, Kavanagh JA, Waddell DS. Fam83d modulates MAP kinase and AKT signaling and is induced during neurogenic skeletal muscle atrophy. Cell Signal 2020; 70:109576. [PMID: 32092437 DOI: 10.1016/j.cellsig.2020.109576] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 02/20/2020] [Accepted: 02/20/2020] [Indexed: 01/08/2023]
Abstract
Skeletal muscle atrophy is a serious health condition that can arise due to aging, cancer, corticosteroid exposure, and denervation. Previous work comparing gene expression profiles in control and denervated muscle tissue revealed for the first time that Fam83d is expressed in skeletal muscle and is significantly induced in response to denervation. Quantitative PCR and Western blot analysis found that Fam83d is more highly expressed in proliferating myoblasts compared to differentiated myotubes. Characterization of the transcriptional regulation of Fam83d showed that ectopic expression of myogenic regulatory factors inhibits Fam83d reporter gene activity. To assess where Fam83d is localized in the cell, Fam83d was fused with green fluorescent protein, expressed in C2C12 cells, and found to localize in a punctate manner to the cytoplasm of muscle cells. To assess function, Fam83d was ectopically expressed in cultured muscle cells and markers of muscle cell differentiation, the MAP Kinase signaling pathway, and the AKT signaling pathway were analyzed. Fam83d overexpression resulted in significant repression of myosin heavy chain and myogenin expression, while phosphorylated ERK and AKT were also significantly repressed. Interestingly, inhibition of the 26S proteasome and the MAP kinase signaling pathway both resulted in stabilization of Fam83d during muscle cell differentiation. Finally, Fam83d has a putative phospholipase D-like domain that appears to be necessary for destabilizing casein kinase Iα and inhibiting ERK phosphorylation in cultured myoblasts. The discovery that Fam83d is expressed in skeletal muscle combined with the observation that Fam83d, a potential modulator of MAP kinase and AKT signaling, is induced in response to neurogenic atrophy helps further our understanding of the molecular and cellular events of skeletal muscle wasting.
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Affiliation(s)
- Lisa M Cooper
- University of North Florida, Department of Biology, 1 UNF Drive, Jacksonville, FL 32224, United States of America
| | - Abby Hanson
- University of North Florida, Department of Biology, 1 UNF Drive, Jacksonville, FL 32224, United States of America
| | - Jack A Kavanagh
- University of North Florida, Department of Biology, 1 UNF Drive, Jacksonville, FL 32224, United States of America
| | - David S Waddell
- University of North Florida, Department of Biology, 1 UNF Drive, Jacksonville, FL 32224, United States of America.
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Tan KT, Ang STJ, Tsai SY. Sarcopenia: Tilting the Balance of Protein Homeostasis. Proteomics 2019; 20:e1800411. [PMID: 31722440 DOI: 10.1002/pmic.201800411] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 11/04/2019] [Indexed: 12/14/2022]
Abstract
Sarcopenia, defined as age-associated decline of muscle mass and function, is a risk factor for mortality and disability, and comorbid with several chronic diseases such as type II diabetes and cardiovascular diseases. Clinical trials showed that nutritional supplements had positive effects on muscle mass, but not on muscle function and strength, demonstrating our limited understanding of the molecular events involved in the ageing muscle. Protein homeostasis, the equilibrium between protein synthesis and degradation, is proposed as the major mechanism underlying the development of sarcopenia. As the key central regulator of protein homeostasis, the mammalian target of rapamycin (mTOR) is proposed to be essential for muscle hypertrophy. Paradoxically, sustained activation of mTOR complex 1 (mTORC1) is associated with a loss of sensitivity to extracellular signaling in the elderly. It is not understood why sustained mTORC1 activity, which should induce muscle hypertrophy, instead results in muscle atrophy. Here, recent findings on the implications of disrupting protein homeostasis on muscle physiology and sarcopenia development in the context of mTOR/protein kinase B (AKT) signaling are reviewed. Understanding the role of these molecular mechanisms during the ageing process will contribute towards the development of targeted therapies that will improve protein metabolism and reduce sarcopenia.
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Affiliation(s)
- Kuan Ting Tan
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 2 Medical Drive, MD9 Admin Office, Singapore, 117597, Singapore
| | - Seok-Ting Jamie Ang
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 2 Medical Drive, MD9 Admin Office, Singapore, 117597, Singapore
| | - Shih-Yin Tsai
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 2 Medical Drive, MD9 Admin Office, Singapore, 117597, Singapore
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Miller BF, Baehr LM, Musci RV, Reid JJ, Peelor FF, Hamilton KL, Bodine SC. Muscle-specific changes in protein synthesis with aging and reloading after disuse atrophy. J Cachexia Sarcopenia Muscle 2019; 10:1195-1209. [PMID: 31313502 PMCID: PMC6903438 DOI: 10.1002/jcsm.12470] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Revised: 05/09/2019] [Accepted: 06/12/2019] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Successful strategies to halt or reverse sarcopenia require a basic understanding of the factors that cause muscle loss with age. Acute periods of muscle loss in older individuals have an incomplete recovery of muscle mass and strength, thus accelerating sarcopenic progression. The purpose of the current study was to further understand the mechanisms underlying the failure of old animals to completely recover muscle mass and function after a period of hindlimb unloading. METHODS Hindlimb unloading was used to induce muscle atrophy in Fischer 344-Brown Norway (F344BN F1) rats at 24, 28, and 30 months of age. Rats were hindlimb unloaded for 14 days and then reloaded at 24 months (Reloaded 24), 28 months (Reloaded 28), and 24 and 28 months (Reloaded 24/28) of age. Isometric torque was determined at 24 months of age (24 months), at 28 months of age (28 months), immediately after 14 days of reloading, and at 30 months of age (30 months). During control or reloaded conditions, rats were labelled with deuterium oxide (D2 O) to determine rates of muscle protein synthesis and RNA synthesis. RESULTS After 14 days of reloading, in vivo isometric torque returned to baseline in Reloaded 24, but not Reloaded 28 and Reloaded 24/28. Despite the failure of Reloaded 28 and Reloaded 24/28 to regain peak force, all groups were equally depressed in peak force generation at 30 months. Increased age did not decrease muscle protein synthesis rates, and in fact, increased resting rates of protein synthesis were measured in the myofibrillar fraction (Fractional synthesis rate (FSR): %/day) of the plantaris (24 months: 2.53 ± 0.17; 30 months: 3.29 ± 0.17), and in the myofibrillar (24 months: 2.29 ± 0.07; 30 months: 3.34 ± 0.11), collagen (24 months: 1.11 ± 0.07; 30 months: 1.55 ± 0.14), and mitochondrial (24 months: 2.38 ± 0.16; 30 months: 3.20 ± 0.10) fractions of the tibialis anterior (TA). All muscles increased myofibrillar protein synthesis (%/day) in Reloaded 24 (soleus: 3.36 ± 0.11, 5.23 ± 0.19; plantaris: 2.53 ± 0.17, 3.66 ± 0.07; TA: 2.29 ± 0.14, 3.15 ± 0.12); however, in Reloaded 28, only the soleus had myofibrillar protein synthesis rates (%/day) >28 months (28 months: 3.80 ± 0.10; Reloaded 28: 4.86 ± 0.19). Across the muscles, rates of protein synthesis were correlated with RNA synthesis (all muscles combined, R2 = 0.807, P < 0.0001). CONCLUSIONS These data add to the growing body of literature that indicate that changes with age, including following disuse atrophy, differ by muscle. In addition, our findings lead to additional questions of the underlying mechanisms by which some muscles are maintained with age while others are not.
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Affiliation(s)
- Benjamin F Miller
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Leslie M Baehr
- Department of Internal Medicine, Endocrinology and Metabolism, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Robert V Musci
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Justin J Reid
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Frederick F Peelor
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Karyn L Hamilton
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Sue C Bodine
- Department of Internal Medicine, Endocrinology and Metabolism, University of Iowa Carver College of Medicine, Iowa City, IA, USA
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Ghaffari MH, Schuh K, Dusel G, Frieten D, Koch C, Prehn C, Adamski J, Sauerwein H, Sadri H. Mammalian target of rapamycin signaling and ubiquitin-proteasome-related gene expression in skeletal muscle of dairy cows with high or normal body condition score around calving. J Dairy Sci 2019; 102:11544-11560. [PMID: 31587900 DOI: 10.3168/jds.2019-17130] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 08/21/2019] [Indexed: 12/17/2022]
Abstract
The objective of the current study was to investigate the effects of overconditioning around calving on gene expression of key components of the mammalian target of rapamycin (mTOR) pathway and ubiquitin-proteasome system (UPS) in skeletal muscle as well as the AA profiles in both serum and muscle of periparturient cows. Fifteen weeks antepartum, 38 multiparous Holstein cows were allocated to either a high body condition group (HBCS; n = 19) or a normal body condition group (NBCS; n = 19) and were fed different diets until dry-off (d -49 relative to calving) to amplify the difference. The groups were also stratified for comparable milk yields (NBCS: 10,361 ± 302 kg; HBCS: 10,315 ± 437 kg). At dry-off, the NBCS cows (parity: 2.42 ± 1.84; body weight: 665 ± 64 kg) had a body condition score (BCS) <3.5 and backfat thickness (BFT) <1.2 cm, whereas the HBCS cows (parity: 3.37 ± 1.67; body weight: 720 ± 57 kg) had a BCS >3.75 and BFT >1.4 cm. During the dry period and the subsequent lactation, both groups were fed identical diets but maintained the BCS and BFT differences. Blood samples and skeletal muscle biopsies (semitendinosus) were repeatedly (d -49, +3, +21, and +84 relative to calving) collected for assessing the concentrations of free AA and the mRNA abundance of various components of mTOR and UPS. The differences in BCS and BFT were maintained throughout the study. The circulating concentrations of most AA with the exception of Gly, Gln, Met, and Phe increased in early lactation in both groups. The serum concentrations of Ala (d +21 and +84) and Orn (d +84) were lower in HBCS cows than in NBCS cows, but those of Gly, His, Leu, Val, Lys, Met, and Orn on d -49 and Ile on d +21 were greater in HBCS cows than in NBCS cows. The serum concentrations of 3-methylhistidine, creatinine, and 3-methylhistidine:creatinine ratio increased after calving (d +3) but did not differ between the groups. The muscle concentrations of all AA (except for Cys) remained unchanged over time and did not differ between groups. The muscle concentrations of Cys were greater on d -49 but tended to be lower on d +21 in HBCS cows than in NBCS cows. On d +21, mTOR and eukaryotic translation initiation factor 4E binding protein 1 mRNA abundance was greater in HBCS cows than in NBCS cows, whereas ribosomal protein S6 kinase 1 was not different between the groups. The mRNA abundance of ubiquitin-activating enzyme 1 (d +21), ubiquitin-conjugating enzyme 1 (d +21), atrogin-1 (d +21), and ring finger protein-1 (d +3) enzymes was greater in HBCS cows than in NBCS cows, whereas ubiquitin-conjugating enzyme 2 was not different between the groups. The increased mRNA abundance of key components of mTOR signaling and of muscle-specific ligases of HBCS cows may indicate a simultaneous activation of anabolic and catabolic processes and thus increased muscle protein turnover, likely as a part of the adaptive response to prevent excessive loss of skeletal muscle mass during early lactation.
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Affiliation(s)
- M H Ghaffari
- Institute of Animal Science, Physiology and Hygiene Unit, University of Bonn, 53115 Bonn, Germany
| | - K Schuh
- Institute of Animal Science, Physiology and Hygiene Unit, University of Bonn, 53115 Bonn, Germany; Department of Life Sciences and Engineering, Animal Nutrition and Hygiene Unit, University of Applied Sciences Bingen, 55411 Bingen am Rhein, Germany
| | - G Dusel
- Department of Life Sciences and Engineering, Animal Nutrition and Hygiene Unit, University of Applied Sciences Bingen, 55411 Bingen am Rhein, Germany
| | - D Frieten
- Educational and Research Centre for Animal Husbandry, Hofgut Neumuehle, 67728 Muenchweiler an der Alsenz, Germany
| | - C Koch
- Educational and Research Centre for Animal Husbandry, Hofgut Neumuehle, 67728 Muenchweiler an der Alsenz, Germany
| | - C Prehn
- Institute of Experimental Genetics, Genome Analysis Center, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764 Neuherberg, Germany
| | - J Adamski
- Institute of Experimental Genetics, Genome Analysis Center, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764 Neuherberg, Germany; Lehrstuhl für Experimentelle Genetik, Technische Universität München, Freising-Weihenstephan 85350, Germany; German Center for Diabetes Research (DZD), München-Neuherberg 85764, Germany; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597
| | - H Sauerwein
- Institute of Animal Science, Physiology and Hygiene Unit, University of Bonn, 53115 Bonn, Germany
| | - H Sadri
- Department of Clinical Science, Faculty of Veterinary Medicine, University of Tabriz, 516616471 Tabriz, Iran.
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Kaifer KA, Villalón E, O'Brien BS, Sison SL, Smith CE, Simon ME, Marquez J, O'Day S, Hopkins AE, Neff R, Rindt H, Ebert AD, Lorson CL. AAV9-mediated delivery of miR-23a reduces disease severity in Smn2B/-SMA model mice. Hum Mol Genet 2019; 28:3199-3210. [PMID: 31211843 PMCID: PMC6859438 DOI: 10.1093/hmg/ddz142] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 05/24/2019] [Accepted: 06/10/2019] [Indexed: 12/20/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a neuromuscular disease caused by deletions or mutations in survival motor neuron 1 (SMN1). The molecular mechanisms underlying motor neuron degeneration in SMA remain elusive, as global cellular dysfunction obscures the identification and characterization of disease-relevant pathways and potential therapeutic targets. Recent reports have implicated microRNA (miRNA) dysregulation as a potential contributor to the pathological mechanism in SMA. To characterize miRNAs that are differentially regulated in SMA, we profiled miRNA levels in SMA induced pluripotent stem cell (iPSC)-derived motor neurons. From this array, miR-23a downregulation was identified selectively in SMA motor neurons, consistent with previous reports where miR-23a functioned in neuroprotective and muscle atrophy-antagonizing roles. Reintroduction of miR-23a expression in SMA patient iPSC-derived motor neurons protected against degeneration, suggesting a potential miR-23a-specific disease-modifying effect. To assess this activity in vivo, miR-23a was expressed using a self-complementary adeno-associated virus serotype 9 (scAAV9) viral vector in the Smn2B/- SMA mouse model. scAAV9-miR-23a significantly reduced the pathology in SMA mice, including increased motor neuron size, reduced neuromuscular junction pathology, increased muscle fiber area, and extended survival. These experiments demonstrate that miR-23a is a novel protective modifier of SMA, warranting further characterization of miRNA dysfunction in SMA.
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Affiliation(s)
- Kevin A Kaifer
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Eric Villalón
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Benjamin S O'Brien
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Samantha L Sison
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Caley E Smith
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Madeline E Simon
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Jose Marquez
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Siri O'Day
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Abigail E Hopkins
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Rachel Neff
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Hansjörg Rindt
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Allison D Ebert
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Christian L Lorson
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
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Qiu J, Zhu J, Zhang R, Liang W, Ma W, Zhang Q, Huang Z, Ding F, Sun H. miR-125b-5p targeting TRAF6 relieves skeletal muscle atrophy induced by fasting or denervation. ANNALS OF TRANSLATIONAL MEDICINE 2019; 7:456. [PMID: 31700892 DOI: 10.21037/atm.2019.08.39] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Background Skeletal muscle atrophy, characterized by accelerated protein degradation, occurs in such conditions as unloading, immobilization, fasting, and denervation. Effective treatments for skeletal muscle atrophy are not yet available. Considering that microRNAs (miRs) may play an important role in the regulation of muscle atrophy, in the present study, we aimed to examine the effect of miR-125b-5p-based therapeutic strategies on skeletal muscle atrophy, and to explore the underlying mechanisms. Methods Fasting-induced atrophic mouse C2C12 myotubes and denervated rat tibialis anterior (TA) muscles were used as in vitro and in vivo models of skeletal muscle atrophy, respectively. The morphological parameters of skeletal muscle were measured by immunostaining-based quantification. The interaction between miR-125b-5p and TRAF6 3'-UTR was detected by luciferase reporter analysis. The mRNA and protein expressions were determined by real-time qPCR and Western blot analysis respectively. The miR mimics/agomir and miR inhibitor/antagomir were transfected into C2C12 myotubes and TA muscles respectively to alter the expression of miR-125b-5p. Results The expression of miR-125b-5p was down-regulated in both atrophic C2C12 myotubes and denervated TA muscles. The interaction between miR-125b-5p and TRAF6 3'-UTR was identified. Overexpression of miR-125b-5p protected skeletal muscle samples from atrophy in vitro and in vivo by targeting TRAF6 through inactivation of several ubiquitin-proteasome system (UPS)- and autophagy-lysosome system (ALS)-related proteins. Conclusions Overexpression of miR-125b-5p may provide a promising therapeutic approach to treat muscle atrophy.
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Affiliation(s)
- Jiaying Qiu
- School of Biology and Basic Medical Sciences, Medical College of Soochow University, Suzhou 215123, China.,Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Jianwei Zhu
- Department of Orthopedics, Affiliated Hospital of Nantong University, Nantong 226001, China
| | - Ru Zhang
- The Second Affiliated Hospital of Nantong University, Nantong University, Nantong 226001, China
| | - Wenpeng Liang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Wenjing Ma
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Qiuyu Zhang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Ziwei Huang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Fei Ding
- School of Biology and Basic Medical Sciences, Medical College of Soochow University, Suzhou 215123, China.,Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Hualin Sun
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
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Machado J, Silveira WA, Gonçalves DA, Schavinski AZ, Khan MM, Zanon NM, Diaz MB, Rudolf R, Kettelhut IC, Navegantes LC. α-Calcitonin gene-related peptide inhibits autophagy and calpain systems and maintains the stability of neuromuscular junction in denervated muscles. Mol Metab 2019; 28:91-106. [PMID: 31331823 PMCID: PMC6822259 DOI: 10.1016/j.molmet.2019.06.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 06/23/2019] [Accepted: 06/28/2019] [Indexed: 11/25/2022] Open
Abstract
Objective Although it is well established that a-calcitonin gene-related peptide (CGRP) stabilizes muscle-type cholinergic receptors nicotinic subunits (AChR), the underlying mechanism by which this neuropeptide regulates muscle protein metabolism and neuromuscular junction (NMJ) morphology is unclear. Methods To elucidate the mechanisms how CGRP controls NMJ stability in denervated mice skeletal muscles, we carried out physiological, pharmacological, and molecular analyses of atrophic muscles induced by sciatic nerve transection. Results Here, we report that CGRP treatment in vivo abrogated the deleterious effects on NMJ upon denervation (DEN), an effect that was associated with suppression of skeletal muscle proteolysis, but not stimulation of protein synthesis. CGRP also blocked the DEN-induced increase in endocytic AChR vesicles and the elevation of autophagosomes per NMJ area. The treatment of denervated animals with rapamycin blocked the stimulatory effects of CGRP on mTORC1 and its inhibitory actions on autophagic flux and NMJ degeneration. Furthermore, CGRP inhibited the DEN-induced hyperactivation of Ca2+-dependent proteolysis, a degradative system that has been shown to destabilize NMJ. Consistently, calpain was found to be activated by cholinergic stimulation in myotubes leading to the dispersal of AChR clusters, an effect that was abolished by CGRP. Conclusion Taken together, these data suggest that the inhibitory effect of CGRP on autophagy and calpain may represent an important mechanism for the preservation of synapse morphology when degradative machinery is exacerbated upon denervation conditions. CGRP exerts antiproteolytic effects in atrophic denervated muscles and maintains the stability of NMJ. CGRP blocks the endocytosis of AChRs and decreases the colocalization of autophagosome to NMJ in denervated muscles. CGRP inhibits the Ca2+-dependent proteolysis, a degradative system that destabilizes NMJ during muscle atrophy. The inhibition of autophagy and calpain induced by CGRP represents an important mechanism for the preservation of synapse.
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Affiliation(s)
- Juliano Machado
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil; Department of Biochemistry/Immunology, Ribeirão Preto Medical School/University of São Paulo, Ribeirão Preto, São Paulo, Brazil; Institute for Diabetes and Cancer (IDC), Helmholtz Center Munich, 85764, Neuherberg, Germany; Joint Heidelberg-IDC Translational Diabetes Program, Inner Medicine I, Heidelberg University Hospital, 69120, Heidelberg, Germany.
| | - Wilian A Silveira
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
| | - Dawit A Gonçalves
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil; Department of Biochemistry/Immunology, Ribeirão Preto Medical School/University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
| | - Aline Zanatta Schavinski
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
| | - Muzamil M Khan
- Institute of Molecular and Cell Biology, University of Applied Sciences Mannheim, Mannheim, Germany; Institute of Medical Technology, University of Heidelberg and University of Applied Sciences Mannheim, Mannheim, Germany.
| | - Neusa M Zanon
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
| | - Mauricio Berriel Diaz
- Institute for Diabetes and Cancer (IDC), Helmholtz Center Munich, 85764, Neuherberg, Germany; Joint Heidelberg-IDC Translational Diabetes Program, Inner Medicine I, Heidelberg University Hospital, 69120, Heidelberg, Germany.
| | - Rüdiger Rudolf
- Institute of Molecular and Cell Biology, University of Applied Sciences Mannheim, Mannheim, Germany; Institute of Medical Technology, University of Heidelberg and University of Applied Sciences Mannheim, Mannheim, Germany.
| | - Isis C Kettelhut
- Department of Biochemistry/Immunology, Ribeirão Preto Medical School/University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
| | - Luiz C Navegantes
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
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32
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Seaborne RA, Hughes DC, Turner DC, Owens DJ, Baehr LM, Gorski P, Semenova EA, Borisov OV, Larin AK, Popov DV, Generozov EV, Sutherland H, Ahmetov II, Jarvis JC, Bodine SC, Sharples AP. UBR5 is a novel E3 ubiquitin ligase involved in skeletal muscle hypertrophy and recovery from atrophy. J Physiol 2019; 597:3727-3749. [PMID: 31093990 DOI: 10.1113/jp278073] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 05/10/2019] [Indexed: 01/03/2023] Open
Abstract
KEY POINTS We have recently identified that a HECT domain E3 ubiquitin ligase, named UBR5, is altered epigenetically (via DNA methylation) after human skeletal muscle hypertrophy, where its gene expression is positively correlated with increasing lean leg mass after training and retraining. In the present study we extensively investigate this novel and uncharacterised E3 ubiquitin ligase (UBR5) in skeletal muscle atrophy, recovery from atrophy and injury, anabolism and hypertrophy. We demonstrated that UBR5 was epigenetically altered via DNA methylation during recovery from atrophy. We also determined that UBR5 was alternatively regulated versus well characterised E3 ligases, MuRF1/MAFbx, at the gene expression level during atrophy, recovery from atrophy and hypertrophy. UBR5 also increased at the protein level during recovery from atrophy and injury, hypertrophy and during human muscle cell differentiation. Finally, in humans, genetic variations of the UBR5 gene were strongly associated with larger fast-twitch muscle fibres and strength/power performance versus endurance/untrained phenotypes. ABSTRACT We aimed to investigate a novel and uncharacterized E3 ubiquitin ligase in skeletal muscle atrophy, recovery from atrophy/injury, anabolism and hypertrophy. We demonstrated an alternate gene expression profile for UBR5 vs. well characterized E3-ligases, MuRF1/MAFbx, where, after atrophy evoked by continuous-low-frequency electrical-stimulation in rats, MuRF1/MAFbx were both elevated, yet UBR5 was unchanged. Furthermore, after recovery of muscle mass post TTX-induced atrophy in rats, UBR5 was hypomethylated and increased at the gene expression level, whereas a suppression of MuRF1/MAFbx was observed. At the protein level, we also demonstrated a significant increase in UBR5 after recovery of muscle mass from hindlimb unloading in both adult and aged rats, as well as after recovery from atrophy evoked by nerve crush injury in mice. During anabolism and hypertrophy, UBR5 gene expression increased following acute loading in three-dimensional bioengineered mouse muscle in vitro, and after chronic electrical stimulation-induced hypertrophy in rats in vivo, without increases in MuRF1/MAFbx. Additionally, UBR5 protein abundance increased following functional overload-induced hypertrophy of the plantaris muscle in mice and during differentiation of primary human muscle cells. Finally, in humans, genetic association studies (>700,000 single nucleotide polymorphisms) demonstrated that the A alleles of rs10505025 and rs4734621 single nucleotide polymorphisms in the UBR5 gene were strongly associated with larger cross-sectional area of fast-twitch muscle fibres and favoured strength/power vs. endurance/untrained phenotypes. Overall, we suggest that: (i) UBR5 comprises a novel E3 ubiquitin ligase that is inversely regulated to MuRF1/MAFbx; (ii) UBR5 is epigenetically regulated; and (iii) UBR5 is elevated at both the gene expression and protein level during recovery from skeletal muscle atrophy and hypertrophy.
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Affiliation(s)
- Robert A Seaborne
- Stem Cells, Ageing and Molecular Physiology Unit, Exercise Metabolism and Adaptation Research Group, Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK.,Institute for Science and Technology in Medicine (ISTM), School of Medicine, Keele University, Keele, UK.,Centre for Genomics and Child Health, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - David C Hughes
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Daniel C Turner
- Stem Cells, Ageing and Molecular Physiology Unit, Exercise Metabolism and Adaptation Research Group, Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK.,Institute for Science and Technology in Medicine (ISTM), School of Medicine, Keele University, Keele, UK
| | - Daniel J Owens
- Stem Cells, Ageing and Molecular Physiology Unit, Exercise Metabolism and Adaptation Research Group, Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Leslie M Baehr
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Piotr Gorski
- Stem Cells, Ageing and Molecular Physiology Unit, Exercise Metabolism and Adaptation Research Group, Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK.,Institute for Science and Technology in Medicine (ISTM), School of Medicine, Keele University, Keele, UK
| | - Ekaterina A Semenova
- Department of Molecular Biology and Genetics, Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
| | - Oleg V Borisov
- Department of Molecular Biology and Genetics, Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia.,Institute for Genomic Statistics and Bioinformatics, University Hospital Bonn, Bonn, Germany
| | - Andrey K Larin
- Department of Molecular Biology and Genetics, Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
| | - Daniil V Popov
- Laboratory of Exercise Physiology, Institute of Biomedical Problems of the Russian Academy of Sciences, Moscow, Russia
| | - Edward V Generozov
- Department of Molecular Biology and Genetics, Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
| | - Hazel Sutherland
- Exercise Metabolism and Adaptation Research Group, Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Ildus I Ahmetov
- Department of Molecular Biology and Genetics, Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia.,Laboratory of Molecular Genetics, Kazan State Medical University, Kazan, Russia.,Department of Physical Education, Plekhanov Russian University of Economics, Moscow, Russia.,Exercise Metabolism and Adaptation Research Group, Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Jonathan C Jarvis
- Exercise Metabolism and Adaptation Research Group, Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Sue C Bodine
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Adam P Sharples
- Stem Cells, Ageing and Molecular Physiology Unit, Exercise Metabolism and Adaptation Research Group, Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK.,Institute for Science and Technology in Medicine (ISTM), School of Medicine, Keele University, Keele, UK
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Rudolf R, Khan MM, Witzemann V. Motor Endplate-Anatomical, Functional, and Molecular Concepts in the Historical Perspective. Cells 2019; 8:E387. [PMID: 31035624 PMCID: PMC6562597 DOI: 10.3390/cells8050387] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 04/20/2019] [Accepted: 04/25/2019] [Indexed: 11/17/2022] Open
Abstract
By mediating voluntary muscle movement, vertebrate neuromuscular junctions (NMJ) play an extraordinarily important role in physiology. While the significance of the nerve-muscle connectivity was already conceived almost 2000 years back, the precise cell and molecular biology of the NMJ have been revealed in a series of fascinating research activities that started around 180 years ago and that continues. In all this time, NMJ research has led to fundamentally new concepts of cell biology, and has triggered groundbreaking advancements in technologies. This review tries to sketch major lines of thought and concepts on NMJ in their historical perspective, in particular with respect to anatomy, function, and molecular components. Furthermore, along these lines, it emphasizes the mutual benefit between science and technology, where one drives the other. Finally, we speculate on potential major future directions for studies on NMJ in these fields.
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Affiliation(s)
- Rüdiger Rudolf
- Institute of Molecular and Cell Biology, Mannheim University of Applied Sciences, 68163 Mannheim, Germany.
- Interdisciplinary Center for Neuroscience, Heidelberg University, 69120 Heidelberg, Germany.
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Germany.
| | - Muzamil Majid Khan
- Cell Biology and Biophysics, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.
| | - Veit Witzemann
- Max Planck Institute for Medical Research, 69120 Heidelberg, Germany.
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34
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West DWD, Marcotte GR, Chason CM, Juo N, Baehr LM, Bodine SC, Baar K. Normal Ribosomal Biogenesis but Shortened Protein Synthetic Response to Acute Eccentric Resistance Exercise in Old Skeletal Muscle. Front Physiol 2019; 9:1915. [PMID: 30692935 PMCID: PMC6339931 DOI: 10.3389/fphys.2018.01915] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 12/18/2018] [Indexed: 01/06/2023] Open
Abstract
Anabolic resistance to feeding in aged muscle is well-characterized; however, whether old skeletal muscle is intrinsically resistant to acute mechanical loading is less clear. The aim of this study was to determine the impact of aging on muscle protein synthesis (MPS), ribosome biogenesis, and protein breakdown in skeletal muscle following a single bout of resistance exercise. Adult male F344/BN rats aged 10 (Adult) and 30 (Old) months underwent unilateral maximal eccentric contractions of the hindlimb. Precursor rRNA increased early post-exercise (6-18 h), preceding elevations in ribosomal mass at 48 h in Adult and Old; there were no age-related differences in these responses. MPS increased early post-exercise in both Adult and Old; however, at 48 h of recovery, MPS returned to baseline in Old but not Adult. This abbreviated protein synthesis response in Old was associated with decreased levels of IRS1 protein and increased BiP, CHOP and eIF2α levels. Other than these responses, anabolic signaling was similar in Adult and Old muscle in the acute recovery phase. Basal proteasome activity was lower in Old, and resistance exercise did not increase the activity of either the ATP-dependent or independent proteasome, or autophagy (Cathepsin L activity) in either Adult or Old muscle. We conclude that MPS and ribosome biogenesis in response to maximal resistance exercise in old skeletal muscle are initially intact; however, the MPS response is abbreviated in Old, which may be the result of ER stress and/or blunted exercise-induced potentiation of the MPS response to feeding.
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Affiliation(s)
- Daniel W D West
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States
| | - George R Marcotte
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, United States
| | - Courtney M Chason
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, United States
| | - Natalie Juo
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, United States
| | - Leslie M Baehr
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States
| | - Sue C Bodine
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States.,Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, United States.,VA Northern California Health Care System, Mather, CA, United States
| | - Keith Baar
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States.,Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, United States.,VA Northern California Health Care System, Mather, CA, United States
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35
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Liu H, Thompson LV. Skeletal muscle denervation investigations: selecting an experimental control wisely. Am J Physiol Cell Physiol 2019; 316:C456-C461. [PMID: 30624984 PMCID: PMC6457105 DOI: 10.1152/ajpcell.00441.2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Unilateral denervation is widely used for studies investigating mechanisms of muscle atrophy. The “contralateral-innervated muscle” is a commonly used experimental control in denervation studies. It is not clear whether denervation unilaterally alters the proteolytic system in the contralateral-innervated muscles. Therefore, the objectives of this rapid report are 1) to determine whether unilateral denervation has an effect on the proteolytic system in contralateral-innervated control muscles and 2) to identify the changes in proteasome properties in denervated muscles after 7- and 14-day tibial nerve transection with either the contralateral-innervated muscles or intact muscles from nonsurgical mice used as the experimental control. In the contralateral-innervated muscles after 7 and 14 days of nerve transection, the proteasome activities and content are significantly increased compared with muscles from nonsurgical mice. When the nonsurgical mice are used as the experimental control, a robust increase in proteasome properties is found in the denervated muscles. This robust increase in proteasome properties is eliminated when the contralateral-innervated muscles are the experimental control. In conclusion, there is a crossover effect from unilateral denervation on proteolytic parameters. As a result, the crossover effect on contralateral-innervated muscles must be considered when an experimental control is selected in a denervation study.
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Affiliation(s)
- Haiming Liu
- Division of Gerontology and Geriatric Medicine, Department of Medicine, School of Medicine, University of Washington, and Geriatric Research, Education, and Clinical Center, Veterans Affairs Puget Sound Healthcare System, Seattle, Washington
| | - LaDora V Thompson
- Department of Physical Therapy and Athletic Training, Boston University , Boston, Massachusetts
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36
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Bouchè M, Lozanoska-Ochser B, Proietti D, Madaro L. Do neurogenic and cancer-induced muscle atrophy follow common or divergent paths? Eur J Transl Myol 2018; 28:7931. [PMID: 30662704 PMCID: PMC6317130 DOI: 10.4081/ejtm.2018.7931] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 12/05/2018] [Indexed: 11/22/2022] Open
Abstract
Skeletal muscle is a dynamic tissue capable of responding to a large variety of physiological stimuli by adjusting muscle fiber size, metabolism and function. However, in pathological conditions such as cancer and neural disorders, this finely regulated homeostasis is impaired leading to severe muscle wasting, reduced muscle fiber size (atrophy), and impaired function. These disease features develop due to enhanced protein breakdown, which relies on two major degradation systems: the ubiquitin-proteasome and the autophagy-lysosome. These systems are independently regulated by different signalling pathways, which in physiological conditions, determine protein and organelle turnover. However, alterations in one or both systems, as it happens in several disorders, leads to enhanced protein breakdown and muscle atrophy. Although this is a common feature in the different types of muscle atrophy, the relative contribution of each of these systems is still under debate. Here, we will briefly describe the regulation and the activity of the ubiquitin-proteasome and the autophagy-lysosome systems during muscle wasting. We will then discuss what we know regarding how these pathways are involved in cancer induced and in neurogenic muscle atrophy, highlighting common and divergent paths. It is now clear that there is no one unifying common mechanism that can be applied to all models of muscle loss. Detailed understanding of the pathways and proteolysis mechanisms involved in each model will hopefully help the development of drugs to counteract muscle wasting in specific conditions.
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Affiliation(s)
- Marina Bouchè
- DAHFMO, Unit of Histology, Sapienza University of Rome, 00161 Rome, Italy.,Interuniversity Institute of Myology, Italy
| | | | - Daisy Proietti
- DAHFMO, Unit of Histology, Sapienza University of Rome, 00161 Rome, Italy.,IRCCS, Fondazione Santa Lucia, Rome, Italy
| | - Luca Madaro
- IRCCS, Fondazione Santa Lucia, Rome, Italy.,Interuniversity Institute of Myology, Italy
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37
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Exercise prevents impaired autophagy and proteostasis in a model of neurogenic myopathy. Sci Rep 2018; 8:11818. [PMID: 30087400 PMCID: PMC6081439 DOI: 10.1038/s41598-018-30365-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 07/26/2018] [Indexed: 01/07/2023] Open
Abstract
Increased proteolytic activity has been widely associated with skeletal muscle atrophy. However, elevated proteolysis is also critical for the maintenance of cellular homeostasis by disposing cytotoxic proteins and non-functioning organelles. We recently demonstrated that exercise activates autophagy and re-establishes proteostasis in cardiac diseases. Here, we characterized the impact of exercise on skeletal muscle autophagy and proteostasis in a model of neurogenic myopathy induced by sciatic nerve constriction in rats. Neurogenic myopathy, characterized by progressive atrophy and impaired contractility, was paralleled by accumulation of autophagy-related markers and loss of acute responsiveness to both colchicine and chloroquine. These changes were correlated with elevated levels of damaged proteins, chaperones and pro-apoptotic markers compared to control animals. Sustained autophagy inhibition using chloroquine in rats (50 mg.kg-1.day-1) or muscle-specific deletion of Atg7 in mice was sufficient to impair muscle contractility in control but not in neurogenic myopathy, suggesting that dysfunctional autophagy is critical in skeletal muscle pathophysiology. Finally, 4 weeks of aerobic exercise training (moderate treadmill running, 5x/week, 1 h/day) prior to neurogenic myopathy improved skeletal muscle autophagic flux and proteostasis. These changes were followed by spared muscle mass and better contractility properties. Taken together, our findings suggest the potential value of exercise in maintaining skeletal muscle proteostasis and slowing down the progression of neurogenic myopathy.
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38
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Xu T, Yang X, Wu C, Qiu J, Fang Q, Wang L, Yu S, Sun H. Pyrroloquinoline quinone attenuates cachexia-induced muscle atrophy via suppression of reactive oxygen species. J Thorac Dis 2018; 10:2752-2759. [PMID: 29997937 PMCID: PMC6006103 DOI: 10.21037/jtd.2018.04.112] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 04/11/2018] [Indexed: 12/23/2022]
Abstract
BACKGROUND Cachexia, a wasting syndrome, is most commonly observed in individuals with advanced cancer including lung cancer, esophageal cancer, liver cancer, etc. The characteristic sign of cachexia is muscle atrophy. To date, effective countermeasures have been still deficiency to alleviate muscle atrophy. Reactive oxygen species (ROS) are important regulators of muscle atrophy. Therefore, the effects of a naturally antioxidant, pyrroloquinoline quinone (PQQ), were explored on muscle atrophy induced by cachexia in the present study. METHODS Tumor necrosis factor-α (TNF-α) induced C2C12 myotubes atrophy model was constructed. The atrophied C2C12 myotubes were dealt with the presence or absence of N-acetyl-L-cysteine (NAC, an antioxidant for ROS abolition) (5 mM) or PQQ (80 µM) for 24 hours. ROS content was determined by dichlorodihydrofluorescein diacetate (DCFH-DA) staining. The diameter of myotubes was analyzed by myosin heavy chain (MHC) staining. The protein levels of MHC, muscle atrophy F-box (MAFbx) and muscle RING finger-1 (MuRF-1) in each group were observed by Western blotting. RESULTS First, ROS generation was enhanced in C2C12 myotubes treated with TNF-α. NAC treatments significantly avoided the reduction in the diameter of C2C12 myotubes, and concomitantly increased MHC levels, and decreased ROS contents, MuRF1 and MAFbx levels. These data suggested that the increased ROS induced by TNF-α might play a central role in muscle wasting. PQQ (a naturally occurring antioxidant) administration inhibited C2C12 myotubes atrophy induced by TNF-α, as evidenced by the increase of the diameter of C2C12 myotubes, together with increased MHC levels and decreased ROS, MAFbx and MuRF-1 levels. CONCLUSIONS PQQ resists atrophic effect dependent on, at least in part, decreased ROS in skeletal muscle treated with TNF-α.
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Affiliation(s)
- Tongtong Xu
- Laboratory of Neuroregeneration, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
- School of Medicine, Nantong University, Nantong 226001, China
| | - Xiaoming Yang
- Laboratory of Neuroregeneration, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Changyue Wu
- School of Medicine, Nantong University, Nantong 226001, China
| | - Jiaying Qiu
- Laboratory of Neuroregeneration, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Qingqing Fang
- Laboratory of Neuroregeneration, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Lingbin Wang
- Laboratory of Neuroregeneration, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Shu Yu
- Laboratory of Neuroregeneration, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Hualin Sun
- Laboratory of Neuroregeneration, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
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Houston FE, Hain BA, Dodd SL. Inhibition of the proteasome partially attenuates atrophy in botulinum neurotoxin treated skeletal muscle. Toxicon 2018; 144:48-54. [PMID: 29407164 DOI: 10.1016/j.toxicon.2018.01.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 01/30/2018] [Accepted: 01/30/2018] [Indexed: 11/26/2022]
Abstract
Botulinum neurotoxin type A (BoNT/A) is used as a therapeutic tool to induce chemical denervation of spastically contracted muscles, yet the neurotoxin can also cause skeletal muscle atrophy. The underlying proteolytic mechanisms that induce this atrophy remain unclear. Our previous work has highlighted increased ubiquitin proteasome system (UPS) activity in soleus muscle of male Sprague Dawley rats following hind limb injection of BoNT/A, with the chymotrypsin-like activity of the 20s proteasome the most active. Thus, we chose to inhibit 20s proteasome activity in BoNT/A injected hind limb to determine the effect on soleus muscle atrophy. Epoxomicin is commonly used to inhibit the proteasome in vivo, binding specifically and irreversibly to the 20s proteasome catalytic subunits. Daily subcutaneous injections of epoxomicin abolished BoNT/A-induced elevations in 20s chymotrypsin-like activity both 3 days and 10 days post BoNT/A injection. Furthermore, BoNT/A-induced elevations in polyubiquitination remained elevated in BoNT/A + epoxomicin treated muscle, presumably due to epoxomicin's inhibition of the proteasome causing a back-up of polyubiquitinated proteins. Despite inhibition of the proteasome, epoxomicin was insufficient to significantly attenuate soleus muscle fiber atrophy 3 days following BoNT/A injection however, 10 days of daily epoxomicin injection was sufficient to spare ∼20% of muscle wasting. The mechanism of the remaining 80% of BoNT/A-induced atrophy presumably occurs via mechanisms outside of the 20s proteasome.
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Affiliation(s)
- Fraser E Houston
- Department of Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Brian A Hain
- Department of Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Stephen L Dodd
- Department of Physiology and Kinesiology, University of Florida, Gainesville, FL, USA.
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Qiu J, Fang Q, Xu T, Wu C, Xu L, Wang L, Yang X, Yu S, Zhang Q, Ding F, Sun H. Mechanistic Role of Reactive Oxygen Species and Therapeutic Potential of Antioxidants in Denervation- or Fasting-Induced Skeletal Muscle Atrophy. Front Physiol 2018; 9:215. [PMID: 29593571 PMCID: PMC5861206 DOI: 10.3389/fphys.2018.00215] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 02/26/2018] [Indexed: 01/07/2023] Open
Abstract
Skeletal muscle atrophy occurs under various conditions, such as disuse, denervation, fasting, aging, and various diseases. Although the underlying molecular mechanisms are still not fully understood, skeletal muscle atrophy is closely associated with reactive oxygen species (ROS) overproduction. In this study, we aimed to investigate the involvement of ROS in skeletal muscle atrophy from the perspective of gene regulation, and further examine therapeutic effects of antioxidants on skeletal muscle atrophy. Microarray data showed that the gene expression of many positive regulators for ROS production were up-regulated and the gene expression of many negative regulators for ROS production were down-regulated in mouse soleus muscle atrophied by denervation (sciatic nerve injury). The ROS level was significantly increased in denervated mouse soleus muscle or fasted C2C12 myotubes that had suffered from fasting (nutrient deprivation). These two muscle samples were then treated with N-acetyl-L-cysteine (NAC, a clinically used antioxidant) or pyrroloquinoline quinone (PQQ, a naturally occurring antioxidant), respectively. As compared to non-treatment, both NAC and PQQ treatment (1) reversed the increase in the ROS level in two muscle samples; (2) attenuated the reduction in the cross-sectional area (CSA) of denervated mouse muscle or in the diameter of fasted C2C12 myotube; (3) increased the myosin heavy chain (MHC) level and decreased the muscle atrophy F-box (MAFbx) and muscle-specific RING finger-1 (MuRF-1) levels in two muscle samples. Collectively, these results suggested that an increased ROS level was, at least partly, responsible for denervation- or fasting-induced skeletal muscle atrophy, and antioxidants might resist the atrophic effect via ROS-related mechanisms.
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Affiliation(s)
- Jiaying Qiu
- Laboratory of Neuroregeneration, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Qingqing Fang
- Laboratory of Neuroregeneration, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Tongtong Xu
- School of Medicine, Nantong University, Nantong, China
| | - Changyue Wu
- School of Medicine, Nantong University, Nantong, China
| | - Lai Xu
- Laboratory of Neuroregeneration, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Lingbin Wang
- Laboratory of Neuroregeneration, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Xiaoming Yang
- Laboratory of Neuroregeneration, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Shu Yu
- Laboratory of Neuroregeneration, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Qi Zhang
- Laboratory of Neuroregeneration, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Fei Ding
- Laboratory of Neuroregeneration, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Hualin Sun
- Laboratory of Neuroregeneration, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China
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Pigna E, Renzini A, Greco E, Simonazzi E, Fulle S, Mancinelli R, Moresi V, Adamo S. HDAC4 preserves skeletal muscle structure following long-term denervation by mediating distinct cellular responses. Skelet Muscle 2018; 8:6. [PMID: 29477142 PMCID: PMC6389241 DOI: 10.1186/s13395-018-0153-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 02/18/2018] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Denervation triggers numerous molecular responses in skeletal muscle, including the activation of catabolic pathways and oxidative stress, leading to progressive muscle atrophy. Histone deacetylase 4 (HDAC4) mediates skeletal muscle response to denervation, suggesting the use of HDAC inhibitors as a therapeutic approach to neurogenic muscle atrophy. However, the effects of HDAC4 inhibition in skeletal muscle in response to long-term denervation have not been described yet. METHODS To further study HDAC4 functions in response to denervation, we analyzed mutant mice in which HDAC4 is specifically deleted in skeletal muscle. RESULTS After an initial phase of resistance to neurogenic muscle atrophy, skeletal muscle with a deletion of HDAC4 lost structural integrity after 4 weeks of denervation. Deletion of HDAC4 impaired the activation of the ubiquitin-proteasome system, delayed the autophagic response, and dampened the OS response in skeletal muscle. Inhibition of the ubiquitin-proteasome system or the autophagic response, if on the one hand, conferred resistance to neurogenic muscle atrophy; on the other hand, induced loss of muscle integrity and inflammation in mice lacking HDAC4 in skeletal muscle. Moreover, treatment with the antioxidant drug Trolox prevented loss of muscle integrity and inflammation in in mice lacking HDAC4 in skeletal muscle, despite the resistance to neurogenic muscle atrophy. CONCLUSIONS These results reveal new functions of HDAC4 in mediating skeletal muscle response to denervation and lead us to propose the combined use of HDAC inhibitors and antioxidant drugs to treat neurogenic muscle atrophy.
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Affiliation(s)
- Eva Pigna
- DAHFMO Unit of Histology and Medical Embryology, Interuniversity Institute of Myology, Sapienza University of Rome, Rome, Italy
| | - Alessandra Renzini
- DAHFMO Unit of Histology and Medical Embryology, Interuniversity Institute of Myology, Sapienza University of Rome, Rome, Italy
| | - Emanuela Greco
- DAHFMO Unit of Histology and Medical Embryology, Interuniversity Institute of Myology, Sapienza University of Rome, Rome, Italy
| | - Elena Simonazzi
- DAHFMO Unit of Histology and Medical Embryology, Interuniversity Institute of Myology, Sapienza University of Rome, Rome, Italy
| | - Stefania Fulle
- Department of Neuroscience Imaging and Clinical Sciences-Section of Physiology and Physiopathology, University "G. d'Annunzio" Chieti-Pescara, Chieti, Italy
| | - Rosa Mancinelli
- Department of Neuroscience Imaging and Clinical Sciences-Section of Physiology and Physiopathology, University "G. d'Annunzio" Chieti-Pescara, Chieti, Italy
| | - Viviana Moresi
- DAHFMO Unit of Histology and Medical Embryology, Interuniversity Institute of Myology, Sapienza University of Rome, Rome, Italy.
| | - Sergio Adamo
- DAHFMO Unit of Histology and Medical Embryology, Interuniversity Institute of Myology, Sapienza University of Rome, Rome, Italy
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Shimizu H, Langenbacher AD, Huang J, Wang K, Otto G, Geisler R, Wang Y, Chen JN. The Calcineurin-FoxO-MuRF1 signaling pathway regulates myofibril integrity in cardiomyocytes. eLife 2017; 6:27955. [PMID: 28826496 PMCID: PMC5576919 DOI: 10.7554/elife.27955] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 08/18/2017] [Indexed: 12/21/2022] Open
Abstract
Altered Ca2+ handling is often present in diseased hearts undergoing structural remodeling and functional deterioration. However, whether Ca2+ directly regulates sarcomere structure has remained elusive. Using a zebrafish ncx1 mutant, we explored the impacts of impaired Ca2+ homeostasis on myofibril integrity. We found that the E3 ubiquitin ligase murf1 is upregulated in ncx1-deficient hearts. Intriguingly, knocking down murf1 activity or inhibiting proteasome activity preserved myofibril integrity, revealing a MuRF1-mediated proteasome degradation mechanism that is activated in response to abnormal Ca2+ homeostasis. Furthermore, we detected an accumulation of the murf1 regulator FoxO in the nuclei of ncx1-deficient cardiomyocytes. Overexpression of FoxO in wild type cardiomyocytes induced murf1 expression and caused myofibril disarray, whereas inhibiting Calcineurin activity attenuated FoxO-mediated murf1 expression and protected sarcomeres from degradation in ncx1-deficient hearts. Together, our findings reveal a novel mechanism by which Ca2+ overload disrupts myofibril integrity by activating a Calcineurin-FoxO-MuRF1-proteosome signaling pathway.
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Affiliation(s)
- Hirohito Shimizu
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
| | - Adam D Langenbacher
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
| | - Jie Huang
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
| | - Kevin Wang
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
| | - Georg Otto
- Genetics and Genomic Medicine, UCL Institute of Child Health, London, United Kingdom
| | - Robert Geisler
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Yibin Wang
- Department of Anesthesiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States.,Department of Medicine and Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States
| | - Jau-Nian Chen
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
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Takahashi H, Suzuki Y, Mohamed JS, Gotoh T, Pereira SL, Alway SE. Epigallocatechin-3-gallate increases autophagy signaling in resting and unloaded plantaris muscles but selectively suppresses autophagy protein abundance in reloaded muscles of aged rats. Exp Gerontol 2017; 92:56-66. [PMID: 28286171 PMCID: PMC5501279 DOI: 10.1016/j.exger.2017.02.075] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 01/24/2017] [Accepted: 02/27/2017] [Indexed: 01/26/2023]
Abstract
We have previously found that Epigallocatechin-3-gallate (EGCg), an abundant catechin in green tea, reduced apoptotic signaling and improved muscle recovery in response to reloading after hindlimb suspension (HS). In this study, we investigated if EGCg altered autophagy signaling in skeletal muscle of old rats in response to HS or reloading after HS. Fischer 344×Brown Norway inbred rats (age 34months) were given 1ml/day of purified EGCg (50mg/kg body weight), or the same sample volume of the vehicle by gavage. One group of animals received HS for 14days and the second group of rats received 14days of HS, then the HS was removed and they were allowed to recover by ambulating normally around the cage for two weeks. EGCg decreased a small number of autophagy genes in control muscles, but it increased the expression of other autophagy genes (e.g., ATG16L2, SNCA, TM9SF1, Pink1, PIM-2) and HS did not attenuate these increases. HS increased Beclin1, ATG7 and LC3-II/I protein abundance in hindlimb muscles. Relative to vehicle treatment, EGCg treatment had greater ATG12 protein abundance (35.8%, P<0.05), but decreased Beclin1 protein levels (-101.1%, P<0.05) after HS. However, in reloaded muscles, EGCg suppressed Beclin1 and LC3-II/I protein abundance as compared to vehicle treated muscles. EGCg appeared to "prime" autophagy signaling before and enhance autophagy gene expression and protein levels during unloading in muscles of aged rats, perhaps to improve the clearance of damaged organelles. However, EGCg suppressed autophagy signaling after reloading, potentially to increase the recovery of hindlimb muscles mass and function after loading is restored.
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Affiliation(s)
- Hideyuki Takahashi
- Divison of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV 26506, United States; Kuju Agricultural Research Center, Graduate School of Agriculture Science, Kyushu University, Naoiri-gun Kuju-cho 4045-4, 878-0201, Oita, Japan
| | - Yutaka Suzuki
- Divison of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV 26506, United States; Research Faculty of Agriculture, Laboratory of Animal Function and Nutrition, Hokkaido University, Kita-9 Nishi-9, Sapporo, Japan
| | - Junaith S Mohamed
- Divison of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV 26506, United States
| | - Takafumi Gotoh
- Kuju Agricultural Research Center, Graduate School of Agriculture Science, Kyushu University, Naoiri-gun Kuju-cho 4045-4, 878-0201, Oita, Japan
| | - Suzette L Pereira
- Discovery Technology, Abbott Nutrition, Columbus, OH 43219, United States
| | - Stephen E Alway
- Divison of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV 26506, United States.
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Blondelle J, Shapiro P, Domenighetti AA, Lange S. Cullin E3 Ligase Activity Is Required for Myoblast Differentiation. J Mol Biol 2017; 429:1045-1066. [PMID: 28238764 DOI: 10.1016/j.jmb.2017.02.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 02/17/2017] [Accepted: 02/18/2017] [Indexed: 01/06/2023]
Abstract
The role of cullin E3-ubiquitin ligases for muscle homeostasis is best known during muscle atrophy, as the cullin-1 substrate adaptor atrogin-1 is among the most well-characterized muscle atrogins. We investigated whether cullin activity was also crucial during terminal myoblast differentiation and aggregation of acetylcholine receptors for the establishment of neuromuscular junctions in vitro. The activity of cullin E3-ligases is modulated through post-translational modification with the small ubiquitin-like modifier nedd8. Using either the Nae1 inhibitor MLN4924 (Pevonedistat) or siRNA against nedd8 in early or late stages of differentiation on C2C12 myoblasts, and primary satellite cells from mouse and human, we show that cullin E3-ligase activity is necessary for each step of the muscle cell differentiation program in vitro. We further investigate known transcriptional repressors for terminal muscle differentiation, namely ZBTB38, Bhlhe41, and Id1. Due to their identified roles for terminal muscle differentiation, we hypothesize that the accumulation of these potential cullin E3-ligase substrates may be partially responsible for the observed phenotype. MLN4924 is currently undergoing clinical trials in cancer patients, and our experiments highlight concerns on the homeostasis and regenerative capacity of muscles in these patients who often experience cachexia.
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Affiliation(s)
- Jordan Blondelle
- Division of Cardiology, University of California San Diego, La Jolla, CA-92093 USA
| | - Paige Shapiro
- Division of Cardiology, University of California San Diego, La Jolla, CA-92093 USA
| | - Andrea A Domenighetti
- Rehabilitation Institute of Chicago, Chicago, IL-60611 USA; Department of Physical Medicine and Rehabilitation, Northwestern University, Chicago, IL-60611, USA
| | - Stephan Lange
- Division of Cardiology, University of California San Diego, La Jolla, CA-92093 USA.
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Sakuma K, Aoi W, Yamaguchi A. Molecular mechanism of sarcopenia and cachexia: recent research advances. Pflugers Arch 2017; 469:573-591. [PMID: 28101649 DOI: 10.1007/s00424-016-1933-3] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 12/28/2016] [Accepted: 12/29/2016] [Indexed: 12/17/2022]
Abstract
Skeletal muscle provides a fundamental basis for human function, enabling locomotion and respiration. Muscle loss occurs as a consequence of several chronic diseases (cachexia) and normal aging (sarcopenia). Although many negative regulators (atrogin-1, muscle ring finger-1, nuclear factor-kappaB (NF-κB), myostatin, etc.) have been proposed to enhance protein degradation during both sarcopenia and cachexia, the adaptation of these mediators markedly differs within both conditions. Sarcopenia and cachectic muscles have been demonstrated to be abundant in myostatin-linked molecules. The ubiquitin-proteasome system (UPS) is activated during rapid atrophy model (cancer cachexia), but few mediators of the UPS change during sarcopenia. NF-κB signaling is activated in cachectic, but not in sarcopenic, muscle. Recent studies have indicated the age-related defect of autophagy signaling in skeletal muscle, whereas autophagic activation occurs in cachectic muscle. This review provides recent research advances dealing with molecular mediators modulating muscle mass in both sarcopenia and cachexia.
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Affiliation(s)
- Kunihiro Sakuma
- Institute for Liberal Arts, Environment and Society, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8550, Japan.
| | - Wataru Aoi
- Laboratory of Health Science, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, 1-5 Hangi-cho Shimogamo, Sakyo-ku, Kyoto, 606-8522, Japan
| | - Akihiko Yamaguchi
- Department of Physical Therapy, Health Sciences University of Hokkaido, Kanazawa, Ishikari-Tobetsu, Hokkaido, 061-0293, Japan
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46
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Liu HM, Ferrington DA, Baumann CW, Thompson LV. Denervation-Induced Activation of the Standard Proteasome and Immunoproteasome. PLoS One 2016; 11:e0166831. [PMID: 27875560 PMCID: PMC5119786 DOI: 10.1371/journal.pone.0166831] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 11/05/2016] [Indexed: 01/07/2023] Open
Abstract
The standard 26S proteasome is responsible for the majority of myofibrillar protein degradation leading to muscle atrophy. The immunoproteasome is an inducible form of the proteasome. While its function has been linked to conditions of atrophy, its contribution to muscle proteolysis remains unclear. Therefore, the purpose of this study was to determine if the immunoproteasome plays a role in skeletal muscle atrophy induced by denervation. Adult male C57BL/6 wild type (WT) and immunoproteasome knockout lmp7-/-/mecl-1-/- (L7M1) mice underwent tibial nerve transection on the left hindlimb for either 7 or 14 days, while control mice did not undergo surgery. Proteasome activity (caspase-, chymotrypsin-, and trypsin- like), protein content of standard proteasome (β1, β5 and β2) and immunoproteasome (LMP2, LMP7 and MECL-1) catalytic subunits were determined in the gastrocnemius muscle. Denervation induced significant atrophy and was accompanied by increased activities and protein content of the catalytic subunits in both WT and L7M1 mice. Although denervation resulted in a similar degree of muscle atrophy between strains, the mice lacking two immunoproteasome subunits showed a differential response in the extent and duration of proteasome features, including activities and content of the β1, β5 and LMP2 catalytic subunits. The results indicate that immunoproteasome deficiency alters the proteasome’s composition and activities. However, the immunoproteasome does not appear to be essential for muscle atrophy induced by denervation.
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Affiliation(s)
- Haiming M. Liu
- Department of Physical Medicine and Rehabilitation, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Deborah A. Ferrington
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Cory W. Baumann
- Department of Physical Medicine and Rehabilitation, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - LaDora V. Thompson
- Department of Physical Medicine and Rehabilitation, University of Minnesota, Minneapolis, Minnesota, United States of America
- * E-mail:
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Bohnert KR, Gallot YS, Sato S, Xiong G, Hindi SM, Kumar A. Inhibition of ER stress and unfolding protein response pathways causes skeletal muscle wasting during cancer cachexia. FASEB J 2016; 30:3053-68. [PMID: 27206451 PMCID: PMC5001510 DOI: 10.1096/fj.201600250rr] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 05/12/2016] [Indexed: 12/25/2022]
Abstract
Cachexia is a devastating syndrome that causes morbidity and mortality in a large number of patients with cancer. However, the mechanisms of cancer cachexia remain poorly understood. Accumulation of misfolded proteins in the endoplasmic reticulum (ER) causes stress. The ER responds to this stress through activating certain pathways commonly known as the unfolding protein response (UPR). The main function of UPR is to restore homeostasis, but excessive or prolonged activation of UPR can lead to pathologic conditions. In this study, we examined the role of ER stress and UPR in regulation of skeletal muscle mass in naïve conditions and during cancer cachexia. Our results demonstrate that multiple markers of ER stress are highly activated in skeletal muscle of Lewis lung carcinoma (LLC) and Apc(Min/+) mouse models of cancer cachexia. Treatment of mice with 4-phenylbutyrate (4-PBA), a chemical chaperon and a potent inhibitor of ER stress, significantly reduced skeletal muscle strength and mass in both control and LLC-bearing mice. Blocking the UPR also increased the proportion of fast-type fibers in soleus muscle of both control and LLC-bearing mice. Inhibition of UPR reduced the activity of Akt/mTOR pathway and increased the expression of the components of the ubiquitin-proteasome system and autophagy in LLC-bearing mice. Moreover, we found that the inhibition of UPR causes severe atrophy in cultured myotubes. Our study provides initial evidence that ER stress and UPR pathways are essential for maintaining skeletal muscle mass and strength and for protection against cancer cachexia.-Bohnert, K. R., Gallot, Y. S., Sato, S., Xiong, G., Hindi, S. M., Kumar, A. Inhibition of ER stress and unfolding protein response pathways causes skeletal muscle wasting during cancer cachexia.
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Affiliation(s)
- Kyle R Bohnert
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Yann S Gallot
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Shuichi Sato
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Guangyan Xiong
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Sajedah M Hindi
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Ashok Kumar
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky, USA
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Atherton PJ, Greenhaff PL, Phillips SM, Bodine SC, Adams CM, Lang CH. Control of skeletal muscle atrophy in response to disuse: clinical/preclinical contentions and fallacies of evidence. Am J Physiol Endocrinol Metab 2016; 311:E594-604. [PMID: 27382036 PMCID: PMC5142005 DOI: 10.1152/ajpendo.00257.2016] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 07/05/2016] [Indexed: 01/08/2023]
Abstract
Muscle wasting resulting wholly or in part from disuse represents a serious medical complication that, when prolonged, can increase morbidity and mortality. Although much knowledge has been gained over the past half century, the underlying etiology by which disuse alters muscle proteostasis remains enigmatic. Multidisciplinary and novel methodologies are needed to fill gaps and overcome barriers to improved patient care. The present review highlights seminal concepts from a symposium at Experimental Biology 2016. These proceedings focus on 1) the role of insulin resistance in mediating disuse-induced changes in muscle protein synthesis (MPS) and breakdown (MPB), as well as cross-talk between carbohydrate and protein metabolism; 2) the relative importance of MPS/MPB in mediating involuntary muscle loss in humans and animals; 3) interpretative limitations associated with MPS/MPB "markers," e.g., MuRF1/MAFbx mRNA; and finally, 4) how OMIC technologies can be leveraged to identify molecular pathways (e.g., ATF4, p53, p21) mediating disuse atrophy. This perspective deals primarily with "simple atrophy" due to unloading. Nonetheless, it is likely that disuse is a pervasive contributor to muscle wasting associated with catabolic disease-related atrophy (i.e., due to associated sedentary behaviour of disease burden). Key knowledge gaps and challenges are identified to stimulate discussion and identify opportunities for translational research. Data from animal and human studies highlight both similarities and differences. Integrated preclinical and clinical research is encouraged to better understand the metabolic and molecular underpinnings and translational relevance,for disuse atrophy. These approaches are crucial to clinically prevent or reverse muscle atrophy, thereby reestablishing homeostasis and recovery.
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Affiliation(s)
- Philip J Atherton
- Royal Derby Medical School, Royal Derby Hospital, Derby, United Kingdom;
| | - Paul L Greenhaff
- MRC-ARUK Centre for Musculoskeletal Ageing Research, ARUK Centre for Sport, Exercise, and Osteoarthritis, School of Life Sciences, The Medical School, University of Nottingham, Nottingham, United Kingdom
| | - Stuart M Phillips
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Sue C Bodine
- Departments of Neurobiology, Physiology and Behavior, and Physiology and Membrane Biology, University of California Davis, Veterans Affairs Northern California Health Care System, Mather, California
| | - Christopher M Adams
- Departments of Internal Mediciane and Molecular Physiology and Biophysics and Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa; Iowa City Veterans Affairs Medical Center, Iowa City, Iowa; and
| | - Charles H Lang
- Department of Cellular and Molecular Physiology, Pennsylvania State College of Medicine, Hershey, Pennsylvania
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49
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Diclofenac induces proteasome and mitochondrial dysfunction in murine cardiomyocytes and hearts. Int J Cardiol 2016; 223:923-935. [PMID: 27589040 DOI: 10.1016/j.ijcard.2016.08.233] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 07/28/2016] [Accepted: 08/12/2016] [Indexed: 12/31/2022]
Abstract
BACKGROUND One of the most common nonsteroidal anti-inflammatory drugs (NSAIDs) used worldwide, diclofenac (DIC), has been linked to increased risk of cardiovascular disease (CVD). The molecular mechanism(s) by which DIC causes CVD is unknown. METHODS Proteasome activities were studied in hearts, livers, and kidneys from male Swiss Webster mice treated with either 100mg/kg DIC for 18h (acute treatment) or 10mg/kg DIC for 28days (chronic treatment). Cultured H9c2 cells and neonatal cardiomyocytes were also treated with different concentrations of DIC and proteasome function, cell death and ROS generation studied. Isolated mouse heart mitochondria were utilized to determine the effect of DIC on various electron transport chain complex activities. RESULTS DIC significantly inhibited the chymotrypsin-like proteasome activity in rat cardiac H9c2 cells, murine neonatal cardiomyocytes, and mouse hearts, but did not affect proteasome subunit expression levels. Proteasome activity was also affected in liver and kidney tissues from DIC treated animals. The levels of polyubiquitinated proteins increased in hearts from DIC treated mice. Importantly, the levels of oxidized proteins increased while the β5i immunoproteasome activity decreased in hearts from DIC treated mice. DIC increased ROS production and cell death in H9c2 cells and neonatal cardiomyocytes while the cardioprotective NSAID, aspirin, had no effect on ROS levels or cell viability. DIC inhibited mitochondrial Complex III, a major source of ROS, and impaired mitochondrial membrane potential suggesting that mitochondria are the major sites of ROS generation. CONCLUSION These results suggest that DIC induces cardiotoxicity by a ROS dependent mechanism involving mitochondrial and proteasome dysfunction.
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Baumann CW, Liu HM, Thompson LV. Denervation-Induced Activation of the Ubiquitin-Proteasome System Reduces Skeletal Muscle Quantity Not Quality. PLoS One 2016; 11:e0160839. [PMID: 27513942 PMCID: PMC4981385 DOI: 10.1371/journal.pone.0160839] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 07/26/2016] [Indexed: 12/20/2022] Open
Abstract
It is well known that the ubiquitin-proteasome system is activated in response to skeletal muscle wasting and functions to degrade contractile proteins. The loss of these proteins inevitably reduces skeletal muscle size (i.e., quantity). However, it is currently unknown whether activation of this pathway also affects function by impairing the muscle’s intrinsic ability to produce force (i.e., quality). Therefore, the purpose of this study was twofold, (1) document how the ubiquitin-proteasome system responds to denervation and (2) identify the physiological consequences of these changes. To induce soleus muscle atrophy, C57BL6 mice underwent tibial nerve transection of the left hindlimb for 7 or 14 days (n = 6–8 per group). At these time points, content of several proteins within the ubiquitin-proteasome system were determined via Western blot, while ex vivo whole muscle contractility was specifically analyzed at day 14. Denervation temporarily increased several key proteins within the ubiquitin-proteasome system, including the E3 ligase MuRF1 and the proteasome subunits 19S, α7 and β5. These changes were accompanied by reductions in absolute peak force and power, which were offset when expressed relative to physiological cross-sectional area. Contrary to peak force, absolute and relative forces at submaximal stimulation frequencies were significantly greater following 14 days of denervation. Taken together, these data represent two keys findings. First, activation of the ubiquitin-proteasome system is associated with reductions in skeletal muscle quantity rather than quality. Second, shortly after denervation, it appears the muscle remodels to compensate for the loss of neural activity via changes in Ca2+ handling.
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Affiliation(s)
- Cory W. Baumann
- Department of Physical Medicine and Rehabilitation, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
| | - Haiming M. Liu
- Department of Physical Medicine and Rehabilitation, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
| | - LaDora V. Thompson
- Department of Physical Medicine and Rehabilitation, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
- * E-mail:
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