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Valentino TR, Burke BI, Kang G, Goh J, Dungan CM, Ismaeel A, Mobley CB, Flythe MD, Wen Y, McCarthy JJ. Microbial-Derived Exerkines Prevent Skeletal Muscle Atrophy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.29.596432. [PMID: 38854012 PMCID: PMC11160717 DOI: 10.1101/2024.05.29.596432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Regular exercise yields a multitude of systemic benefits, many of which may be mediated through the gut microbiome. Here, we report that cecal microbial transplants (CMTs) from exercise-trained vs. sedentary mice have modest benefits in reducing skeletal muscle atrophy using a mouse model of unilaterally hindlimb-immobilization. Direct administration of top microbial-derived exerkines from an exercise-trained gut microbiome preserved muscle function and prevented skeletal muscle atrophy.
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Affiliation(s)
- Taylor R Valentino
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY
- Center for Muscle Biology, College of Health Sciences, University of Kentucky, Lexington, KY
- Current Address: Buck Institute for Research on Aging, Novato, CA
| | - Benjamin I Burke
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY
- Center for Muscle Biology, College of Health Sciences, University of Kentucky, Lexington, KY
| | - Gyumin Kang
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY
- Center for Muscle Biology, College of Health Sciences, University of Kentucky, Lexington, KY
- Division of Biomedical Informatics, Department of Internal Medicine, College of Medicine, University of Kentucky, Lexington, KY
| | - Jensen Goh
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY
- Center for Muscle Biology, College of Health Sciences, University of Kentucky, Lexington, KY
| | - Cory M Dungan
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY
- Center for Muscle Biology, College of Health Sciences, University of Kentucky, Lexington, KY
- Current Address: Department of Health, Human Performance, and Recreation, Robbins College of Health & Human Sciences, Baylor University, Waco, TX
| | - Ahmed Ismaeel
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY
- Center for Muscle Biology, College of Health Sciences, University of Kentucky, Lexington, KY
| | - C Brooks Mobley
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY
- Center for Muscle Biology, College of Health Sciences, University of Kentucky, Lexington, KY
- Current Address: School of Kinesiology, Auburn University, Auburn, AL
| | - Michael D Flythe
- USDA Agriculture Research Service, Forage-Animal Production Research Unit, University of Kentucky, Lexington, KY
- Department of Animal and Food Sciences, College of Agriculture, Food and Environment, University of Kentucky, Lexington, KY
| | - Yuan Wen
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY
- Center for Muscle Biology, College of Health Sciences, University of Kentucky, Lexington, KY
- Division of Biomedical Informatics, Department of Internal Medicine, College of Medicine, University of Kentucky, Lexington, KY
| | - John J McCarthy
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY
- Center for Muscle Biology, College of Health Sciences, University of Kentucky, Lexington, KY
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Kirby TJ, Zahr HC, Fong EHH, Lammerding J. Eliminating elevated p53 signaling fails to rescue skeletal muscle defects or extend survival in lamin A/C-deficient mice. Cell Death Discov 2024; 10:245. [PMID: 38778055 PMCID: PMC11111808 DOI: 10.1038/s41420-024-01998-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2024] [Revised: 04/25/2024] [Accepted: 04/29/2024] [Indexed: 05/25/2024] Open
Abstract
Lamins A and C, encoded by the LMNA gene, are nuclear intermediate filaments that provide structural support to the nucleus and contribute to chromatin organization and transcriptional regulation. LMNA mutations cause muscular dystrophies, dilated cardiomyopathy, and other diseases. The mechanisms by which many LMNA mutations result in muscle-specific diseases have remained elusive, presenting a major hurdle in the development of effective treatments. Previous studies using striated muscle laminopathy mouse models found that cytoskeletal forces acting on mechanically fragile Lmna-mutant nuclei led to transient nuclear envelope rupture, extensive DNA damage, and activation of DNA damage response (DDR) pathways in skeletal muscle cells in vitro and in vivo. Furthermore, hearts of Lmna mutant mice have elevated activation of the tumor suppressor protein p53, a central regulator of DDR signaling. We hypothesized that elevated p53 activation could present a pathogenic mechanism in striated muscle laminopathies, and that eliminating p53 activation could improve muscle function and survival in laminopathy mouse models. Supporting a pathogenic function of p53 activation in muscle, stabilization of p53 was sufficient to reduce contractility and viability in wild-type muscle cells in vitro. Using three laminopathy models, we found that increased p53 activity in Lmna-mutant muscle cells primarily resulted from mechanically induced damage to the myonuclei, and not from altered transcriptional regulation due to loss of lamin A/C expression. However, global deletion of p53 in a severe muscle laminopathy model did not reduce the disease phenotype or increase survival, indicating that additional drivers of disease must contribute to the disease pathogenesis.
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Affiliation(s)
- Tyler J Kirby
- Department of Physiology, Amsterdam Cardiovascular Sciences, Amsterdam Movement Sciences, Amsterdam UMC location Vrije Universiteit Amsterdam, Amsterdam, Netherlands.
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA.
| | - Hind C Zahr
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA
| | - Ern Hwei Hannah Fong
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA
| | - Jan Lammerding
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA.
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA.
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Deppen JN, Ginn SC, Tang EO, Wang L, Brockman ML, Levit RD. Alginate-Encapsulated Mesenchymal Stromal Cells Improve Hind Limb Ischemia in a Translational Swine Model. J Am Heart Assoc 2024; 13:e029880. [PMID: 38639336 PMCID: PMC11179867 DOI: 10.1161/jaha.123.029880] [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: 02/17/2023] [Accepted: 03/01/2024] [Indexed: 04/20/2024]
Abstract
BACKGROUND Cellular therapies have been investigated to improve blood flow and prevent amputation in peripheral artery disease with limited efficacy in clinical trials. Alginate-encapsulated mesenchymal stromal cells (eMSCs) demonstrated improved retention and survival and promoted vascular generation in murine hind limb ischemia through their secretome, but large animal evaluation is necessary for human applicability. We sought to determine the efficacy of eMSCs for peripheral artery disease-induced limb ischemia through assessment in our durable swine hind limb ischemia model. METHODS AND RESULTS Autologous bone marrow eMSCs or empty alginate capsules were intramuscularly injected 2 weeks post-hind limb ischemia establishment (N=4/group). Improvements were quantified for 4 weeks through walkway gait analysis, contrast angiography, blood pressures, fluorescent microsphere perfusion, and muscle morphology and histology. Capsules remained intact with mesenchymal stromal cells retained for 4 weeks. Adenosine-induced perfusion deficits and muscle atrophy in ischemic limbs were significantly improved by eMSCs versus empty capsules (mean±SD, 1.07±0.19 versus 0.41±0.16, P=0.002 for perfusion ratios and 2.79±0.12 versus 1.90±0.62 g/kg, P=0.029 for ischemic muscle mass). Force- and temporal-associated walkway parameters normalized (ratio, 0.63±0.35 at week 3 versus 1.02±0.19 preligation; P=0.17), and compensatory footfall patterning was diminished in eMSC-administered swine (12.58±8.46% versus 34.85±15.26%; P=0.043). Delivery of eMSCs was associated with trending benefits in collateralization, local neovascularization, and muscle fibrosis. Hypoxia-cultured porcine mesenchymal stromal cells secreted vascular endothelial growth factor and tissue inhibitor of metalloproteinase 2. CONCLUSIONS This study demonstrates the promise of the mesenchymal stromal cell secretome at improving peripheral artery disease outcomes and the potential for this novel swine model to serve as a component of the preclinical pipeline for advanced therapies.
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Affiliation(s)
- Juline N. Deppen
- Wallace H. Coulter Department of Biomedical EngineeringGeorgia Institute of Technology and Emory UniversityAtlantaGA
- Division of CardiologyEmory University School of MedicineAtlantaGA
| | - Sydney C. Ginn
- Wallace H. Coulter Department of Biomedical EngineeringGeorgia Institute of Technology and Emory UniversityAtlantaGA
- Division of CardiologyEmory University School of MedicineAtlantaGA
| | - Erica O. Tang
- Division of CardiologyEmory University School of MedicineAtlantaGA
| | - Lanfang Wang
- Division of CardiologyEmory University School of MedicineAtlantaGA
| | | | - Rebecca D. Levit
- Division of CardiologyEmory University School of MedicineAtlantaGA
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Ruple BA, Mattingly ML, Godwin JS, McIntosh MC, Kontos NJ, Agyin-Birikorang A, Michel JM, Plotkin DL, Chen SY, Ziegenfuss TN, Fruge AD, Gladden LB, Robinson AT, Mobley CB, Mackey AL, Roberts MD. The effects of resistance training on denervated myofibers, senescent cells, and associated protein markers in middle-aged adults. FASEB J 2024; 38:e23621. [PMID: 38651653 PMCID: PMC11047210 DOI: 10.1096/fj.202302103rrr] [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: 10/16/2023] [Revised: 04/04/2024] [Accepted: 04/08/2024] [Indexed: 04/25/2024]
Abstract
Denervated myofibers and senescent cells are hallmarks of skeletal muscle aging. However, sparse research has examined how resistance training affects these outcomes. We investigated the effects of unilateral leg extensor resistance training (2 days/week for 8 weeks) on denervated myofibers, senescent cells, and associated protein markers in apparently healthy middle-aged participants (MA, 55 ± 8 years old, 17 females, 9 males). We obtained dual-leg vastus lateralis (VL) muscle cross-sectional area (mCSA), VL biopsies, and strength assessments before and after training. Fiber cross-sectional area (fCSA), satellite cells (Pax7+), denervated myofibers (NCAM+), senescent cells (p16+ or p21+), proteins associated with denervation and senescence, and senescence-associated secretory phenotype (SASP) proteins were analyzed from biopsy specimens. Leg extensor peak torque increased after training (p < .001), while VL mCSA trended upward (interaction p = .082). No significant changes were observed for Type I/II fCSAs, NCAM+ myofibers, or senescent (p16+ or p21+) cells, albeit satellite cells increased after training (p = .037). While >90% satellite cells were not p16+ or p21+, most p16+ and p21+ cells were Pax7+ (>90% on average). Training altered 13 out of 46 proteins related to muscle-nerve communication (all upregulated, p < .05) and 10 out of 19 proteins related to cellular senescence (9 upregulated, p < .05). Only 1 out of 17 SASP protein increased with training (IGFBP-3, p = .031). In conclusion, resistance training upregulates proteins associated with muscle-nerve communication in MA participants but does not alter NCAM+ myofibers. Moreover, while training increased senescence-related proteins, this coincided with an increase in satellite cells but not alterations in senescent cell content or SASP proteins. These latter findings suggest shorter term resistance training is an unlikely inducer of cellular senescence in apparently healthy middle-aged participants. However, similar study designs are needed in older and diseased populations before definitive conclusions can be drawn.
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Affiliation(s)
| | | | | | | | | | | | - J. Max Michel
- School of Kinesiology, Auburn University, Auburn, AL, USA
| | | | | | | | | | | | | | | | - Abigail L. Mackey
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, DK
- Institute of Sports Medicine Copenhagen, Department of Orthopaedic Surgery, Copenhagen University Hospital – Bispebjerg and Frederiksberg, Copenhagen, Denmark
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Calulo Rivera Z, González-Seguel F, Horikawa-Strakovsky A, Granger C, Sarwal A, Dhar S, Ntoumenopoulos G, Chen J, Bumgardner VKC, Parry SM, Mayer KP, Wen Y. MyoVision-US: an Artificial Intelligence-Powered Software for Automated Analysis of Skeletal Muscle Ultrasonography. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.04.26.24306153. [PMID: 38746458 PMCID: PMC11092729 DOI: 10.1101/2024.04.26.24306153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Introduction/Aims Muscle ultrasound has high utility in clinical practice and research; however, the main challenges are the training and time required for manual analysis to achieve objective quantification of morphometry. This study aimed to develop and validate a software tool powered by artificial intelligence (AI) by measuring its consistency and predictability of expert manual analysis quantifying lower limb muscle ultrasound images across healthy, acute, and chronic illness subjects. Methods Quadriceps complex (QC [rectus femoris and vastus intermedius]) and tibialis anterior (TA) muscle ultrasound images of healthy, intensive care unit, and/or lung cancer subjects were captured with portable devices. Automated analyses of muscle morphometry were performed using a custom-built deep-learning model (MyoVision-US), while manual analyses were performed by experts. Consistency between manual and automated analyses was determined using intraclass correlation coefficients (ICC), while predictability of MyoVision -US was calculated using adjusted linear regression (adj.R 2 ). Results Manual analysis took approximately 24 hours to analyze all 180 images, while MyoVision - US took 247 seconds, saving roughly 99.8%. Consistency between the manual and automated analyses by ICC was good to excellent for all QC (ICC:0.85-0.99) and TA (ICC:0.93-0.99) measurements, even for critically ill (ICC:0.91-0.98) and lung cancer (ICC:0.85-0.99) images. The predictability of MyoVision-US was moderate to strong for QC (adj.R 2 :0.56-0.94) and TA parameters (adj.R 2 :0.81-0.97). Discussion The application of AI automating lower limb muscle ultrasound analyses showed excellent consistency and strong predictability compared with human analysis. Future work needs to explore AI-powered models for the evaluation of other skeletal muscle groups.
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Scarpelli MC, Bergamasco JGA, Godwin JS, Mesquita PHC, Chaves TS, Silva DG, Bittencourt D, Dias NF, Medalha Junior RA, Carello Filho PC, Angleri V, Costa LAR, Kavazis AN, Ugrinowitsch C, Roberts MD, Libardi CA. Resistance training-induced changes in muscle proteolysis and extracellular matrix remodeling biomarkers in the untrained and trained states. Eur J Appl Physiol 2024:10.1007/s00421-024-05484-5. [PMID: 38653795 DOI: 10.1007/s00421-024-05484-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 03/21/2024] [Indexed: 04/25/2024]
Abstract
PURPOSE Resistance training (RT) induces muscle growth at varying rates across RT phases, and evidence suggests that the muscle-molecular responses to training bouts become refined or attenuated in the trained state. This study examined how proteolysis-related biomarkers and extracellular matrix (ECM) remodeling factors respond to a bout of RT in the untrained (UT) and trained (T) state. METHODS Participants (19 women and 19 men) underwent 10 weeks of RT. Biopsies of vastus lateralis were collected before and after (24 h) the first (UT) and last (T) sessions. Vastus lateralis cross-sectional area (CSA) was assessed before and after the experimental period. RESULTS There were increases in muscle and type II fiber CSAs. In both the UT and T states, calpain activity was upregulated and calpain-1/-2 protein expression was downregulated from Pre to 24 h. Calpain-2 was higher in the T state. Proteasome activity and 20S proteasome protein expression were upregulated from Pre to 24 h in both the UT and T. However, proteasome activity levels were lower in the T state. The expression of poly-ubiquitinated proteins was unchanged. MMP activity was downregulated, and MMP-9 protein expression was elevated from Pre to 24 h in UT and T. Although MMP-14 protein expression was acutely unchanged, this marker was lower in T state. TIMP-1 protein levels were reduced Pre to 24 h in UT and T, while TIMP-2 protein levels were unchanged. CONCLUSION Our results are the first to show that RT does not attenuate the acute-induced response of proteolysis and ECM remodeling-related biomarkers.
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Affiliation(s)
- Maíra C Scarpelli
- MUSCULAB - Laboratory of Neuromuscular Adaptations to Resistance Training, Department of Physical Education, Federal University of São Carlos - UFSCar, Rod. Washington Luiz, km 235 - SP 310, São Carlos, SP, 13565-905, Brazil
- School of Kinesiology, Nutrabolt Applied and Molecular Sciences Laboratory, Auburn University, 301 Wire Road, Office 286, Auburn, AL, 36849, USA
| | - João G A Bergamasco
- MUSCULAB - Laboratory of Neuromuscular Adaptations to Resistance Training, Department of Physical Education, Federal University of São Carlos - UFSCar, Rod. Washington Luiz, km 235 - SP 310, São Carlos, SP, 13565-905, Brazil
- School of Kinesiology, Nutrabolt Applied and Molecular Sciences Laboratory, Auburn University, 301 Wire Road, Office 286, Auburn, AL, 36849, USA
| | - Joshua S Godwin
- School of Kinesiology, Nutrabolt Applied and Molecular Sciences Laboratory, Auburn University, 301 Wire Road, Office 286, Auburn, AL, 36849, USA
| | - Paulo H C Mesquita
- School of Kinesiology, Nutrabolt Applied and Molecular Sciences Laboratory, Auburn University, 301 Wire Road, Office 286, Auburn, AL, 36849, USA
| | - Talisson S Chaves
- MUSCULAB - Laboratory of Neuromuscular Adaptations to Resistance Training, Department of Physical Education, Federal University of São Carlos - UFSCar, Rod. Washington Luiz, km 235 - SP 310, São Carlos, SP, 13565-905, Brazil
| | - Deivid G Silva
- MUSCULAB - Laboratory of Neuromuscular Adaptations to Resistance Training, Department of Physical Education, Federal University of São Carlos - UFSCar, Rod. Washington Luiz, km 235 - SP 310, São Carlos, SP, 13565-905, Brazil
| | - Diego Bittencourt
- MUSCULAB - Laboratory of Neuromuscular Adaptations to Resistance Training, Department of Physical Education, Federal University of São Carlos - UFSCar, Rod. Washington Luiz, km 235 - SP 310, São Carlos, SP, 13565-905, Brazil
| | - Nathalia F Dias
- MUSCULAB - Laboratory of Neuromuscular Adaptations to Resistance Training, Department of Physical Education, Federal University of São Carlos - UFSCar, Rod. Washington Luiz, km 235 - SP 310, São Carlos, SP, 13565-905, Brazil
| | - Ricardo A Medalha Junior
- MUSCULAB - Laboratory of Neuromuscular Adaptations to Resistance Training, Department of Physical Education, Federal University of São Carlos - UFSCar, Rod. Washington Luiz, km 235 - SP 310, São Carlos, SP, 13565-905, Brazil
| | - Paulo C Carello Filho
- MUSCULAB - Laboratory of Neuromuscular Adaptations to Resistance Training, Department of Physical Education, Federal University of São Carlos - UFSCar, Rod. Washington Luiz, km 235 - SP 310, São Carlos, SP, 13565-905, Brazil
| | - Vitor Angleri
- MUSCULAB - Laboratory of Neuromuscular Adaptations to Resistance Training, Department of Physical Education, Federal University of São Carlos - UFSCar, Rod. Washington Luiz, km 235 - SP 310, São Carlos, SP, 13565-905, Brazil
| | - Luiz A R Costa
- School of Physical Education and Sport, University of São Paulo - USP, São Paulo, SP, Brazil
| | - Andreas N Kavazis
- School of Kinesiology, Nutrabolt Applied and Molecular Sciences Laboratory, Auburn University, 301 Wire Road, Office 286, Auburn, AL, 36849, USA
| | - Carlos Ugrinowitsch
- School of Physical Education and Sport, University of São Paulo - USP, São Paulo, SP, Brazil
- Department of Health Sciences and Human Performance, University of Tampa, Tampa, FL, USA
| | - Michael D Roberts
- School of Kinesiology, Nutrabolt Applied and Molecular Sciences Laboratory, Auburn University, 301 Wire Road, Office 286, Auburn, AL, 36849, USA.
| | - Cleiton A Libardi
- MUSCULAB - Laboratory of Neuromuscular Adaptations to Resistance Training, Department of Physical Education, Federal University of São Carlos - UFSCar, Rod. Washington Luiz, km 235 - SP 310, São Carlos, SP, 13565-905, Brazil.
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Yao Z, Wo J, Zheng E, Yang J, Li H, Li X, Li J, Luo Y, Wang T, Fan Z, Zhan Y, Yang Y, Wu Z, Yin L, Meng F. A deep learning-based approach for fully automated segmentation and quantitative analysis of muscle fibers in pig skeletal muscle. Meat Sci 2024; 213:109506. [PMID: 38603965 DOI: 10.1016/j.meatsci.2024.109506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 02/06/2024] [Accepted: 04/01/2024] [Indexed: 04/13/2024]
Abstract
Muscle fiber properties exert a significant influence on pork quality, with cross-sectional area (CSA) being a crucial parameter closely associated with various meat quality indicators, such as shear force. Effectively identifying and segmenting muscle fibers in a robust manner constitutes a vital initial step in determining CSA. This step is highly intricate and time-consuming, necessitating an accurate and automated analytical approach. One limitation of existing methods is their tendency to perform well on high signal-to-noise ratio images of intact, healthy muscle fibers but their lack of validation on more complex image datasets featuring significant morphological changes, such as the presence of ice crystals. In this study, we undertake the fully automatic segmentation of muscle fiber microscopic images stained with myosin adenosine triphosphate (mATPase) activity using a deep learning architecture known as SOLOv2. Our objective is to efficiently derive accurate measurements of muscle fiber size and distribution. Tests conducted on actual images demonstrate that our method adeptly handles the intricate task of muscle fiber segmentation, yielding quantitative results amenable to statistical analysis and displaying reliability comparable to manual analysis.
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Affiliation(s)
- Zekai Yao
- State Key Laboratory of Swine and Poultry Breeding Industry/ Guangdong Key Laboratory of Animal Breeding and Nutrition, Institute of Animal Science, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, PR China; College of Animal Science and National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou 510642, PR China
| | - Jingjie Wo
- College of Mathematics and Informatics, South China Agricultural University, Guangzhou 510642, PR China
| | - Enqin Zheng
- College of Animal Science and National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou 510642, PR China; Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, South China Agricultural University, Guangzhou 510642, PR China
| | - Jie Yang
- College of Animal Science and National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou 510642, PR China; Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, South China Agricultural University, Guangzhou 510642, PR China
| | - Hao Li
- State Key Laboratory of Swine and Poultry Breeding Industry/ Guangdong Key Laboratory of Animal Breeding and Nutrition, Institute of Animal Science, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, PR China; College of Animal Science and National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou 510642, PR China
| | - Xinxin Li
- State Key Laboratory of Swine and Poultry Breeding Industry/ Guangdong Key Laboratory of Animal Breeding and Nutrition, Institute of Animal Science, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, PR China; College of Animal Science and National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou 510642, PR China
| | - Jianhao Li
- State Key Laboratory of Swine and Poultry Breeding Industry/ Guangdong Key Laboratory of Animal Breeding and Nutrition, Institute of Animal Science, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, PR China
| | - Yizhi Luo
- State Key Laboratory of Swine and Poultry Breeding Industry/ Guangdong Key Laboratory of Animal Breeding and Nutrition, Institute of Animal Science, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, PR China; Institute of Facility Agriculture, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, PR China
| | - Ting Wang
- College of Animal Science and National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou 510642, PR China
| | - Zhenfei Fan
- College of Animal Science and National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou 510642, PR China
| | - Yuexin Zhan
- College of Animal Science and National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou 510642, PR China
| | - Yingshan Yang
- College of Animal Science and National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou 510642, PR China
| | - Zhenfang Wu
- College of Animal Science and National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou 510642, PR China; Yunfu Subcenter of Guangdong Laboratory for Lingnan Modern Agriculture, Yunfu 527400, PR China; Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, South China Agricultural University, Guangzhou 510642, PR China.
| | - Ling Yin
- College of Mathematics and Informatics, South China Agricultural University, Guangzhou 510642, PR China.
| | - Fanming Meng
- State Key Laboratory of Swine and Poultry Breeding Industry/ Guangdong Key Laboratory of Animal Breeding and Nutrition, Institute of Animal Science, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, PR China.
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8
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Nolt GL, Keeble AR, Wen Y, Strong AC, Thomas NT, Valentino TR, Brightwell CR, Murach KA, Patrizia S, Weinstabl H, Gollner A, McCarthy JJ, Fry CS, Franti M, Filareto A, Peterson CA, Dungan CM. Inhibition of p53-MDM2 binding reduces senescent cell abundance and improves the adaptive responses of skeletal muscle from aged mice. GeroScience 2024; 46:2153-2176. [PMID: 37872294 PMCID: PMC10828311 DOI: 10.1007/s11357-023-00976-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 10/09/2023] [Indexed: 10/25/2023] Open
Abstract
Skeletal muscle adaptation to external stimuli, such as regeneration following injury and hypertrophy in response to resistance exercise, are blunted with advanced age. The accumulation of senescent cells, along with defects in myogenic progenitor cell (MPC) proliferation, have been strongly linked as contributing factors to age-associated impairment in muscle adaptation. p53 plays an integral role in all these processes, as upregulation of p53 causes apoptosis in senescent cells and prevents mitotic catastrophe in MPCs from old mice. The goal of this study was to determine if a novel pharmaceutical agent (BI01), which functions by upregulating p53 through inhibition of binding to MDM2, the primary p53 regulatory protein, improves muscle regeneration and hypertrophy in old mice. BI01 effectively reduced the number of senescent cells in vitro but had no effect on MPC survival or proliferation at a comparable dose. Following repeated oral gavage with 2 mg/kg of BI01 (OS) or vehicle (OV), old mice (24 months) underwent unilateral BaCl2 injury in the tibialis anterior (TA) muscle, with PBS injections serving as controls. After 7 days, satellite cell number was higher in the TA of OS compared to OV mice, as was the expression of genes involved in ATP production. By 35 days, old mice treated with BI01 displayed reduced senescent cell burden, enhanced regeneration (higher muscle mass and fiber cross-sectional area) and restoration of muscle function relative to OV mice. To examine the impact of 2 mg/kg BI01 on muscle hypertrophy, the plantaris muscle was subjected to 28 days of mechanical overload (MOV) in OS and OV mice. In response to MOV, OS mice had larger plantaris muscles and muscle fibers than OV mice, particularly type 2b + x fibers, associated with reduced senescent cells. Together our data show that BI01 is an effective senolytic agent that may also augment muscle metabolism to enhance muscle regeneration and hypertrophy in old mice.
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Affiliation(s)
- Georgia L Nolt
- Department of Physiology, University of Kentucky, Lexington, KY, USA
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - Alexander R Keeble
- Department of Physiology, University of Kentucky, Lexington, KY, USA
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - Yuan Wen
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Physical Therapy, University of Kentucky, Lexington, KY, USA
| | - Aubrey C Strong
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - Nicholas T Thomas
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Athletic Training and Clinical Nutrition, University of Kentucky, Lexington, KY, USA
| | - Taylor R Valentino
- Department of Physiology, University of Kentucky, Lexington, KY, USA
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - Camille R Brightwell
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Athletic Training and Clinical Nutrition, University of Kentucky, Lexington, KY, USA
| | - Kevin A Murach
- Department of Health, Human Performance, and Recreation, University of Arkansas, Fayetteville, AR, USA
| | - Sini Patrizia
- Regenerative Medicine, Boehringer Ingelheim Pharmaceuticals Inc., 900 Ridgebury Road, Ridgefield, CT, 06877, USA
| | - Harald Weinstabl
- Boehringer Ingelheim RCV, Boehringer Ingelheim Pharmaceuticals Inc., Vienna, Austria
| | - Andreas Gollner
- Boehringer Ingelheim RCV, Boehringer Ingelheim Pharmaceuticals Inc., Vienna, Austria
| | - John J McCarthy
- Department of Physiology, University of Kentucky, Lexington, KY, USA
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - Christopher S Fry
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Athletic Training and Clinical Nutrition, University of Kentucky, Lexington, KY, USA
| | - Michael Franti
- Regenerative Medicine, Boehringer Ingelheim Pharmaceuticals Inc., 900 Ridgebury Road, Ridgefield, CT, 06877, USA
| | - Antonio Filareto
- Regenerative Medicine, Boehringer Ingelheim Pharmaceuticals Inc., 900 Ridgebury Road, Ridgefield, CT, 06877, USA.
| | - Charlotte A Peterson
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Physical Therapy, University of Kentucky, Lexington, KY, USA
| | - Cory M Dungan
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA.
- Department of Physical Therapy, University of Kentucky, Lexington, KY, USA.
- Department of Health, Human Performance, and Recreation, Baylor University, One Bear Place #97313, Waco, TX, 76706, USA.
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9
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Tamura Y, Jee E, Kouzaki K, Kotani T, Nakazato K. Monocarboxylate transporter 4 deficiency enhances high-intensity interval training-induced metabolic adaptations in skeletal muscle. J Physiol 2024; 602:1313-1340. [PMID: 38513062 DOI: 10.1113/jp285719] [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: 10/06/2023] [Accepted: 02/29/2024] [Indexed: 03/23/2024] Open
Abstract
High-intensity exercise stimulates glycolysis, subsequently leading to elevated lactate production within skeletal muscle. While lactate produced within the muscle is predominantly released into the circulation via the monocarboxylate transporter 4 (MCT4), recent research underscores lactate's function as an intercellular and intertissue signalling molecule. However, its specific intracellular roles within muscle cells remains less defined. In this study, our objective was to elucidate the effects of increased intramuscular lactate accumulation on skeletal muscle adaptation to training. To achieve this, we developed MCT4 knockout mice and confirmed that a lack of MCT4 indeed results in pronounced lactate accumulation in skeletal muscle during high-intensity exercise. A key finding was the significant enhancement in endurance exercise capacity at high intensities when MCT4 deficiency was paired with high-intensity interval training (HIIT). Furthermore, metabolic adaptations supportive of this enhanced exercise capacity were evident with the combination of MCT4 deficiency and HIIT. Specifically, we observed a substantial uptick in the activity of glycolytic enzymes, notably hexokinase, glycogen phosphorylase and pyruvate kinase. The mitochondria also exhibited heightened pyruvate oxidation capabilities, as evidenced by an increase in oxygen consumption when pyruvate served as the substrate. This mitochondrial adaptation was further substantiated by elevated pyruvate dehydrogenase activity, increased activity of isocitrate dehydrogenase - the rate-limiting enzyme in the TCA cycle - and enhanced function of cytochrome c oxidase, pivotal to the electron transport chain. Our findings provide new insights into the physiological consequences of lactate accumulation in skeletal muscle during high-intensity exercises, deepening our grasp of the molecular intricacies underpinning exercise adaptation. KEY POINTS: We pioneered a unique line of monocarboxylate transporter 4 (MCT4) knockout mice specifically tailored to the ICR strain, an optimal background for high-intensity exercise studies. A deficiency in MCT4 exacerbates the accumulation of lactate in skeletal muscle during high-intensity exercise. Pairing MCT4 deficiency with high-intensity interval training (HIIT) results in a synergistic boost in high-intensity exercise capacity, observable both at the organismal level (via a treadmill running test) and at the muscle tissue level (through an ex vivo muscle contractile function test). Coordinating MCT4 deficiency with HIIT enhances both the glycolytic enzyme activities and mitochondrial capacity to oxidize pyruvate.
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Affiliation(s)
- Yuki Tamura
- Faculty of Sport Science, Nippon Sport Science University, Tokyo, Japan
- Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan
- Research Institute for Sport Science, Nippon Sport Science University, Tokyo, Japan
- Sport Training Center, Nippon Sport Science University, Tokyo, Japan
- High Performance Center, Nippon Sport Science University, Tokyo, Japan
- Center for Coaching Excellence, Nippon Sport Science University, Tokyo, Japan
| | - Eunbin Jee
- Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan
| | - Karina Kouzaki
- Research Institute for Sport Science, Nippon Sport Science University, Tokyo, Japan
- Faculty of Medical Science, Nippon Sport Science University, Tokyo, Japan
- Graduate School of Medical and Health Science, Nippon Sport Science University, Tokyo, Japan
| | - Takaya Kotani
- Research Institute for Sport Science, Nippon Sport Science University, Tokyo, Japan
| | - Koichi Nakazato
- Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan
- Research Institute for Sport Science, Nippon Sport Science University, Tokyo, Japan
- Faculty of Medical Science, Nippon Sport Science University, Tokyo, Japan
- Graduate School of Medical and Health Science, Nippon Sport Science University, Tokyo, Japan
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10
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Owen MK, Casadonte KR, Thomas NT, Latham CM, Brightwell CR, Thompson KL, Hawk GS, Jacobs CA, Johnson DL, Fry CS, Noehren B. Sex Differences in Quadriceps Atrophy After Anterior Cruciate Ligament Tear. Sports Health 2024:19417381241230612. [PMID: 38436049 DOI: 10.1177/19417381241230612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2024] Open
Abstract
BACKGROUND Female athletes lag behind their male counterparts in recovery from anterior cruciate ligament (ACL) injury. Quadriceps muscle size and strength are crucial factors for regaining function after ACL injury, but little is known about how these metrics vary due to biological sex. HYPOTHESIS Female patients have reduced vastus lateralis fiber cross-sectional area (CSA) and lower quadriceps strength after ACL injury than male patients. STUDY DESIGN Cross-sectional study. LEVEL OF EVIDENCE Level 4. METHODS A total of 60 participants with recent ACL tear were evaluated for vastus lateralis muscle fiber CSA, isometric quadriceps peak torque, and quadriceps rate of torque development. Linear mixed models were fit to determine differences across sex and limb for each variable of interest. RESULTS The female group averaged almost 20% atrophy between limbs (P < 0.01), while the male group averaged just under 4% (P = 0.05). Strength deficits between limbs were comparable between female and male groups. CONCLUSION Immediately after ACL injury, female patients have greater between-limb differences in muscle fiber CSA but between-limb strength deficits comparable with those of male patients. CLINICAL RELEVANCE These results indicate that the underpinnings of strength loss differ based on biological sex, and thus individual patients could benefit from a sex-specific treatment approach to ACL injury.
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Affiliation(s)
- Meredith K Owen
- Department of Physical Therapy, University of Kentucky, Lexington, Kentucky
| | - Kelsey R Casadonte
- Department of Physical Therapy, University of Kentucky, Lexington, Kentucky
| | - Nicholas T Thomas
- Department of Athletic Training and Clinical Nutrition, University of Kentucky, Lexington, Kentucky
| | - Christine M Latham
- Department of Athletic Training and Clinical Nutrition, University of Kentucky, Lexington, Kentucky
| | - Camille R Brightwell
- Department of Athletic Training and Clinical Nutrition, University of Kentucky, Lexington, Kentucky
| | - Katherine L Thompson
- Dr. Bing Zhang Department of Statistics, University of Kentucky, Lexington, Kentucky
| | - Gregory S Hawk
- Dr. Bing Zhang Department of Statistics, University of Kentucky, Lexington, Kentucky
| | - Cale A Jacobs
- Department of Orthopaedic Surgery and Sports Medicine, University of Kentucky, Lexington, Kentucky
| | - Darren L Johnson
- Department of Orthopaedic Surgery and Sports Medicine, University of Kentucky, Lexington, Kentucky
| | - Christopher S Fry
- Department of Athletic Training and Clinical Nutrition, University of Kentucky, Lexington, Kentucky
| | - Brian Noehren
- Department of Physical Therapy, University of Kentucky, Lexington, Kentucky, and Department of Orthopaedic Surgery and Sports Medicine, University of Kentucky, Lexington, Kentucky
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11
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Sterczala AJ, Rodriguez‐Ortiz N, Feigel ED, Krajewski K, Martin BJ, Sekel NM, Lovalekar M, Kargl CK, Koltun KJ, Van Eck C, Flanagan S, Connaboy C, Wardle SL, O'Leary TJ, Greeves JP, Nindl BC. Skeletal muscle adaptations to high-intensity, low-volume concurrent resistance and interval training in recreationally active men and women. Physiol Rep 2024; 12:e15953. [PMID: 38490811 PMCID: PMC10942853 DOI: 10.14814/phy2.15953] [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: 11/01/2023] [Revised: 12/16/2023] [Accepted: 12/16/2023] [Indexed: 03/17/2024] Open
Abstract
This study compared the structural and cellular skeletal muscle factors underpinning adaptations in maximal strength, power, aerobic capacity, and lean body mass to a 12-week concurrent resistance and interval training program in men and women. Recreationally active women and men completed three training sessions per week consisting of high-intensity, low-volume resistance training followed by interval training performed using a variety upper and lower body exercises representative of military occupational tasks. Pre- and post-training vastus lateralis muscle biopsies were analyzed for changes in muscle fiber type, cross-sectional area, capillarization, and mitochondrial biogenesis marker content. Changes in maximal strength, aerobic capacity, and lean body mass (LBM) were also assessed. Training elicited hypertrophy of type I (12.9%; p = 0.016) and type IIa (12.7%; p = 0.007) muscle fibers in men only. In both sexes, training decreased type IIx fiber expression (1.9%; p = 0.046) and increased total PGC-1α (29.7%, p < 0.001) and citrate synthase (11.0%; p < 0.014) content, but had no effect on COX IV content or muscle capillarization. In both sexes, training increased maximal strength and LBM but not aerobic capacity. The concurrent training program was effective at increasing strength and LBM but not at improving aerobic capacity or skeletal muscle adaptations underpinning aerobic performance.
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Affiliation(s)
- Adam J. Sterczala
- Neuromuscular Research Laboratory and Warrior Human Performance Research CenterUniversity of PittsburghPittsburghPennsylvaniaUSA
- Present address:
Human Engineering Research LaboratoriesVA Pittsburgh Healthcare SystemPittsburghPennsylvaniaUSA
| | - Nathaniel Rodriguez‐Ortiz
- Neuromuscular Research Laboratory and Warrior Human Performance Research CenterUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Evan D. Feigel
- Neuromuscular Research Laboratory and Warrior Human Performance Research CenterUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Kellen T. Krajewski
- Neuromuscular Research Laboratory and Warrior Human Performance Research CenterUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Brian J. Martin
- Neuromuscular Research Laboratory and Warrior Human Performance Research CenterUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Nicole M. Sekel
- Neuromuscular Research Laboratory and Warrior Human Performance Research CenterUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Mita Lovalekar
- Neuromuscular Research Laboratory and Warrior Human Performance Research CenterUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Christopher K. Kargl
- Neuromuscular Research Laboratory and Warrior Human Performance Research CenterUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Kristen J. Koltun
- Neuromuscular Research Laboratory and Warrior Human Performance Research CenterUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Carola Van Eck
- Department of Orthopaedic SurgeryUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Shawn D. Flanagan
- Neuromuscular Research Laboratory and Warrior Human Performance Research CenterUniversity of PittsburghPittsburghPennsylvaniaUSA
- Present address:
Center for Lower Extremity Ambulatory ResearchRosalind Franklin University of Medicine & ScienceNorth ChicagoILUSA
| | - Christopher Connaboy
- Neuromuscular Research Laboratory and Warrior Human Performance Research CenterUniversity of PittsburghPittsburghPennsylvaniaUSA
- Present address:
Center for Lower Extremity Ambulatory ResearchRosalind Franklin University of Medicine & ScienceNorth ChicagoILUSA
| | - Sophie L. Wardle
- Army Health and Performance ResearchArmy HeadquartersAndoverUK
- Present address:
Norwich Medical School, Faculty of Medicine and Health SciencesUniversity of East AngliaNorwichUK
| | - Thomas J. O'Leary
- Army Health and Performance ResearchArmy HeadquartersAndoverUK
- Present address:
Norwich Medical School, Faculty of Medicine and Health SciencesUniversity of East AngliaNorwichUK
| | - Julie P. Greeves
- Army Health and Performance ResearchArmy HeadquartersAndoverUK
- Present address:
Norwich Medical School, Faculty of Medicine and Health SciencesUniversity of East AngliaNorwichUK
- Present address:
Division of Surgery and Interventional ScienceUniversity College LondonLondonUK
| | - Bradley C. Nindl
- Neuromuscular Research Laboratory and Warrior Human Performance Research CenterUniversity of PittsburghPittsburghPennsylvaniaUSA
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12
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Beaudry AG, Law ML, Gilley-Connor KR, Buley H, Dungan CM, Nascimento CMC, Vichaya EG, Wiggs MP. Diet-induced obesity does not exacerbate cachexia in male mice bearing Lewis-lung carcinoma tumors. Am J Physiol Regul Integr Comp Physiol 2024; 326:R254-R265. [PMID: 38252513 DOI: 10.1152/ajpregu.00208.2023] [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: 08/27/2023] [Revised: 01/11/2024] [Accepted: 01/11/2024] [Indexed: 01/24/2024]
Abstract
Cachexia is a muscle-wasting syndrome commonly observed in patients with cancer, which can significantly worsen clinical outcomes. Because of a global rise in obesity, the coexistence of cachexia in obese individuals poses unique challenges, with the impact of excessive adiposity on cachexia severity and underlying pathophysiology not well defined. Understanding the interplay between cachexia and obesity is crucial for improving diagnosis and treatment strategies for these patients; therefore, the present study examined differences in cachexia between lean and obese mice bearing Lewis lung carcinoma (LLC) tumors. Nine-week-old, male C57Bl6J mice were placed on either a chow or a high-fat diet (HFD) for 9 wk. After the diet intervention, mice were inoculated with LLC or vehicle. Markers of cachexia, such as body and muscle loss, were noted in both chow and HFD groups with tumors. Tumor weight of HFD animals was greater than that of chow. LLC tumors reduced gastrocnemius, plantaris, and soleus mass, regardless of diet. The tibialis anterior and plantaris mass and cross-sectional area of type IIb/x fibers in the gastrocnemius were not different between HFD-chow, HFD-tumor, and chow-tumor. Using RNA sequencing (RNA-seq) of the plantaris muscle from chow-tumor and HFD-tumor groups, we identified ∼400 differentially expressed genes. Bioinformatic analysis identified changes in lipid metabolism, mitochondria, bioenergetics, and proteasome degradation. Atrophy was not greater despite larger tumor burden in animals fed an HFD, and RNA-seq data suggests that partial protection is mediated through differences in mitochondrial function and protein degradation, which may serve as future mechanistic targets.NEW & NOTEWORTHY This study provides timely information on the interaction between obesity and cancer cachexia. Lean and obese animals show signs of cachexia with reduced body weight, adipose tissue, and gastrocnemius muscle mass. There was not significant wasting in the tibialis anterior, plantaris, or fast twitch fibers in the gastrocnemius muscle of obese animals with tumors. RNA-seq analysis reveals that obese tumor bearing animals had differential expression of mitochondria- and degradation-related genes, which may direct future studies in mechanistic research.
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Affiliation(s)
- Anna G Beaudry
- Department of Health, Human Performance, and Recreation, Baylor University, Waco, Texas, United States
| | - Michelle L Law
- Department of Human Sciences and Design, Baylor University, Waco, Texas, United States
| | - Kayla R Gilley-Connor
- Department of Psychology and Neuroscience, Baylor University, Waco, Texas, United States
| | - Hailey Buley
- Department of Psychology and Neuroscience, Baylor University, Waco, Texas, United States
| | - Cory M Dungan
- Department of Health, Human Performance, and Recreation, Baylor University, Waco, Texas, United States
| | | | - Elisabeth G Vichaya
- Department of Psychology and Neuroscience, Baylor University, Waco, Texas, United States
| | - Michael P Wiggs
- Department of Health, Human Performance, and Recreation, Baylor University, Waco, Texas, United States
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13
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Koopmans PJ, Williams‐Frey TD, Zwetsloot KA. Stuart has got the PoWeR! Skeletal muscle adaptations to a novel heavy progressive weighted wheel running exercise model in C57BL/6 mice. Exp Physiol 2024; 109:271-282. [PMID: 37974360 PMCID: PMC10988744 DOI: 10.1113/ep091494] [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: 08/25/2023] [Accepted: 10/18/2023] [Indexed: 11/19/2023]
Abstract
Murine exercise models are developed to study the molecular and cellular mechanisms regulating muscle mass. A progressive weighted wheel running model, named 'PoWeR', was previously developed to serve as a more translatable alternative to involuntary resistance-type exercise models in rodents, such as synergist ablation. However, mice still run great distances despite the added resistance as evidenced by a large glycolytic-to-oxidative shift in muscle fibre type. Thus, PoWeR reflects a blended resistance/endurance model. In an attempt to bias PoWeR further towards resistance-type exercise, we developed a novel heavy PoWeR model (hPoWeR) utilizing higher wheel loads (max of 12.5 g vs 6 g). Adult male C57BL/6 mice voluntarily performed an 8-week progressive loading protocol (PoWeR or hPoWeR). Running distance peaked at ∼5-6 km day-1 in both treatments and was maintained by PoWeR mice, but declined in the hPoWeR mice as load increased beyond 7.5 g. Peak isometric force of the gastrocnemius-soleus-plantaris complex tended to increase in wheel running treatments. Soleus mass increased by 19% and 24% in PoWeR and hPoWeR treatments, respectively, and plantaris fibre cross-sectional area was greater in hPoWeR, compared to PoWeR. There were fewer glycolytic and more oxidative fibres in the soleus and plantaris muscles in the PoWeR treatment, but not hPoWeR. Collectively, these data suggest hPoWeR may modestly alter skeletal muscle supporting the aim of better reflecting typical resistance training adaptations, in line with decreased running volume and exposure to higher resistance. Regardless, PoWeR remains an effective hypertrophic concurrent training model in mice.
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Affiliation(s)
- Pieter J. Koopmans
- Integrative Muscle Physiology LaboratoryAppalachian State UniversityBooneNorth CarolinaUSA
- Department of Public Health and Exercise ScienceAppalachian State UniversityBooneNorth CarolinaUSA
- Cell and Molecular Biology ProgramUniversity of ArkansasFayettevilleArkansasUSA
| | - Therin D. Williams‐Frey
- Integrative Muscle Physiology LaboratoryAppalachian State UniversityBooneNorth CarolinaUSA
- Department of BiologyAppalachian State UniversityBooneNorth CarolinaUSA
| | - Kevin A. Zwetsloot
- Integrative Muscle Physiology LaboratoryAppalachian State UniversityBooneNorth CarolinaUSA
- Department of Public Health and Exercise ScienceAppalachian State UniversityBooneNorth CarolinaUSA
- Department of BiologyAppalachian State UniversityBooneNorth CarolinaUSA
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14
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Ismaeel A, McDermott MM, Joshi JK, Sturgis JC, Zhang D, Ho KJ, Sufit R, Ferrucci L, Peterson CA, Kosmac K. Cocoa flavanols, Nrf2 activation, and oxidative stress in peripheral artery disease: mechanistic findings in muscle based on outcomes from a randomized trial. Am J Physiol Cell Physiol 2024; 326:C589-C605. [PMID: 38189132 DOI: 10.1152/ajpcell.00573.2023] [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: 10/30/2023] [Revised: 12/23/2023] [Accepted: 12/23/2023] [Indexed: 01/09/2024]
Abstract
The pathophysiology of muscle damage in peripheral artery disease (PAD) includes increased oxidant production and impaired antioxidant defenses. Epicatechin (EPI), a naturally occurring flavanol, has antioxidant properties that may mediate the beneficial effects of natural products such as cocoa. In a phase II randomized trial, a cocoa-flavanol-rich beverage significantly improved walking performance compared with a placebo in people with PAD. In the present work, the molecular mechanisms underlying the therapeutic effect of cocoa flavanols were investigated by analyzing baseline and follow-up muscle biopsies from participants. Increases in nuclear factor erythroid 2-related factor 2 (Nrf2) target antioxidants heme oxygenase-1 (HO-1) and NAD(P)H dehydrogenase [quinone] 1 (NQO1) in the cocoa group were significantly associated with reduced accumulation of central nuclei, a myopathy indicator, in type II muscle fibers (P = 0.017 and P = 0.023, respectively). Protein levels of the mitochondrial respiratory complex III subunit, cytochrome b-c1 complex subunit 2 (UQCRC2), were significantly higher in the cocoa group than in the placebo group (P = 0.032), and increases in UQCRC2 were significantly associated with increased levels of Nrf2 target antioxidants HO-1 and NQO1 (P = 0.001 and P = 0.035, respectively). Exposure of non-PAD human myotubes to ex vivo serum from patients with PAD reduced Nrf2 phosphorylation, an indicator of activation, increased hydrogen peroxide production and oxidative stress, and reduced mitochondrial respiration. Treatment of myotubes with EPI in the presence of serum from patients with PAD increased Nrf2 phosphorylation and protected against PAD serum-induced oxidative stress and mitochondrial dysfunction. Overall, these findings suggest that cocoa flavanols may enhance antioxidant capacity in PAD via Nrf2 activation.NEW & NOTEWORTHY The current study supports the hypothesis that in people with PAD, cocoa flavanols activate Nrf2, thereby increasing antioxidant protein levels, protecting against skeletal muscle damage, and increasing mitochondrial protein abundance. These results suggest that Nrf2 activation may be an important therapeutic target for improving walking performance in people with PAD.
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Affiliation(s)
- Ahmed Ismaeel
- Deparment of Physiology, University of Kentucky, Lexington, Kentucky, United States
- Center for Muscle Biology, University of Kentucky, Lexington, Kentucky, United States
| | - Mary M McDermott
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States
| | - Jai K Joshi
- Department of Physical Therapy, University of Kentucky, Lexington, Kentucky, United States
| | - Jada C Sturgis
- Center for Muscle Biology, University of Kentucky, Lexington, Kentucky, United States
- Department of Physical Therapy, University of Kentucky, Lexington, Kentucky, United States
| | - Dongxue Zhang
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States
| | - Karen J Ho
- Department of Surgery, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States
| | - Robert Sufit
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States
| | - Luigi Ferrucci
- National Institute on Aging, Intramural Research Program, Baltimore, Maryland, United States
| | - Charlotte A Peterson
- Center for Muscle Biology, University of Kentucky, Lexington, Kentucky, United States
- Department of Physical Therapy, University of Kentucky, Lexington, Kentucky, United States
| | - Kate Kosmac
- Department of Physical Therapy, Augusta University, Augusta, Georgia, United States
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15
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Yamaguchi T, Kouzaki K, Sasaki K, Nakazato K. Alterations in neuromuscular junction morphology with ageing and endurance training modulate neuromuscular transmission and myofibre composition. J Physiol 2024. [PMID: 38173183 DOI: 10.1113/jp285143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Accepted: 12/12/2023] [Indexed: 01/05/2024] Open
Abstract
Both ageing and exercise training affect the neuromuscular junction (NMJ) structure. Morphological alterations in the NMJ have been considered to influence neuromuscular transmission and myofibre properties, but the direct link between the morphology and function has yet to be established. We measured the neuromuscular transmission, myofibre composition and NMJ structure of 5-month-old (young) and 24-month-old untrained (aged control) and trained (aged trained) mice. Aged trained mice were subjected to 2 months of endurance training before the measurement. Neuromuscular transmission was evaluated in vivo as the ratio of ankle plantar flexion torque evoked by the sciatic nerve stimulation to that by direct muscle stimulation. The torque ratio was significantly lower in aged mice than in young and aged trained mice at high-frequency stimulations, showing a significant positive correlation with voluntary grip strength. The degree of pre- to post-synaptic overlap of the NMJ was also significantly lower in aged mice and positively correlated with the torque ratio. We also found that the proportion of fast-twitch fibres in the soleus muscle decreased with age, and that age-related denervation occurred preferentially in fast-twitch fibres. Age-related denervation and a shift in myofibre composition were partially prevented by endurance training. These results suggest that age-related deterioration of the NMJ structure impairs neuromuscular transmission and alters myofibre composition, but these alterations can be prevented by structural amelioration of NMJ with endurance training. Our findings highlight the importance of the NMJ as a major determinant of age-related deterioration of skeletal muscles and the clinical significance of endurance training as a countermeasure. KEY POINTS: The neuromuscular junction (NMJ) plays an essential role in neuromuscular transmission and the maintenance of myofibre properties. We show that neuromuscular transmission is impaired with ageing but recovered by endurance training, which contributes to alterations in voluntary strength. Neuromuscular transmission is associated with the degree of pre- to post-synaptic overlap of the NMJ. Age-related denervation of fast-twitch fibres and a shift in myofibre composition toward a slower phenotype are partially prevented by endurance training. Our study provides substantial evidence that age-related and exercise-induced alterations in neuromuscular transmission and myofibre properties are associated with morphological changes in the NMJ.
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Affiliation(s)
- Tatsuhiro Yamaguchi
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
- Japan Society for the Promotion of Science, Tokyo, Japan
| | - Karina Kouzaki
- Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan
| | - Kazushige Sasaki
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
| | - Koichi Nakazato
- Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan
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16
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Blemker SS, Brooks SV, Esser KA, Saul KR. Fiber-type traps: revisiting common misconceptions about skeletal muscle fiber types with application to motor control, biomechanics, physiology, and biology. J Appl Physiol (1985) 2024; 136:109-121. [PMID: 37994416 DOI: 10.1152/japplphysiol.00337.2023] [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: 05/30/2023] [Revised: 10/24/2023] [Accepted: 11/13/2023] [Indexed: 11/24/2023] Open
Abstract
Skeletal muscle is a highly complex tissue that is studied by scientists from a wide spectrum of disciplines, including motor control, biomechanics, exercise science, physiology, cell biology, genetics, regenerative medicine, orthopedics, and engineering. Although this diversity in perspectives has led to many important discoveries, historically, there has been limited overlap in discussions across fields. This has led to misconceptions and oversimplifications about muscle biology that can create confusion and potentially slow scientific progress across fields. The purpose of this synthesis paper is to bring together research perspectives across multiple muscle fields to identify common assumptions related to muscle fiber type that are points of concern to clarify. These assumptions include 1) classification by myosin isoform and fiber oxidative capacity is equivalent, 2) fiber cross-sectional area (CSA) is a surrogate marker for myosin isoform or oxidative capacity, and 3) muscle force-generating capacity can be inferred from myosin isoform. We address these three fiber-type traps and provide some context for how these misunderstandings can and do impact experimental design, computational modeling, and interpretations of findings, from the perspective of a range of fields. We stress the dangers of generalizing findings about "muscle fiber types" among muscles or across species or sex, and we note the importance for precise use of common terminology across the muscle fields.
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Affiliation(s)
- Silvia S Blemker
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, United States
| | - Susan V Brooks
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, United States
| | - Karyn A Esser
- Department of Physiology and Aging, University of Florida, Gainesville, Florida, United States
| | - Katherine R Saul
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, North Carolina, United States
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17
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Wen Y, Latham CM, Moore AN, Thomas NT, Lancaster BD, Reeves KA, Keeble AR, Fry CS, Johnson DL, Thompson KL, Noehren B, Fry JL. Vitamin D status associates with skeletal muscle loss after anterior cruciate ligament reconstruction. JCI Insight 2023; 8:e170518. [PMID: 37856482 PMCID: PMC10795826 DOI: 10.1172/jci.insight.170518] [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: 03/21/2023] [Accepted: 10/17/2023] [Indexed: 10/21/2023] Open
Abstract
BACKGROUNDAlthough 25-hydroxyvitamin D [25(OH)D] concentrations of 30 ng/mL or higher are known to reduce injury risk and boost strength, the influence on anterior cruciate ligament reconstruction (ACLR) outcomes remains unexamined. This study aimed to define the vitamin D signaling response to ACLR, assess the relationship between vitamin D status and muscle fiber cross-sectional area (CSA) and bone density outcomes, and discover vitamin D receptor (VDR) targets after ACLR.METHODSTwenty-one young, healthy, physically active participants with recent ACL tears were enrolled (17.8 ± 3.2 years, BMI 26.0 ± 3.5 kg/m2). Data were collected through blood samples, vastus lateralis biopsies, dual energy x-ray bone density measurements, and isokinetic dynamometer measures at baseline, 1 week, 4 months, and 6 months after ACLR. The biopsies facilitated CSA, Western blotting, RNA-seq, and VDR ChIP-seq analyses.RESULTSACLR surgery led to decreased circulating bioactive vitamin D and increased VDR and activating enzyme expression in skeletal muscle 1 week after ACLR. Participants with less than 30 ng/mL 25(OH)D levels (n = 13) displayed more significant quadriceps fiber CSA loss 1 week and 4 months after ACLR than those with 30 ng/mL or higher (n = 8; P < 0.01 for post hoc comparisons; P = 0.041 for time × vitamin D status interaction). RNA-seq and ChIP-seq data integration revealed genes associated with energy metabolism and skeletal muscle recovery, potentially mediating the impact of vitamin D status on ACLR recovery. No difference in bone mineral density losses between groups was observed.CONCLUSIONCorrecting vitamin D status prior to ACLR may aid in preserving skeletal muscle during recovery.FUNDINGNIH grants R01AR072061, R01AR071398-04S1, and K99AR081367.
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Affiliation(s)
- Yuan Wen
- Center for Muscle Biology, College of Health Sciences
- Department of Physiology, College of Medicine
- Division of Biomedical Informatics, Department of Internal Medicine, College of Medicine
| | | | | | | | | | | | - Alexander R. Keeble
- Center for Muscle Biology, College of Health Sciences
- Department of Physiology, College of Medicine
| | | | | | - Katherine L. Thompson
- Dr. Bing Zhang Department of Statistics, University of Kentucky, Lexington, Kentucky, USA
| | - Brian Noehren
- Center for Muscle Biology, College of Health Sciences
- Department of Orthopaedic Surgery & Sports Medicine, and
| | - Jean L. Fry
- Center for Muscle Biology, College of Health Sciences
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18
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Brightwell CR, Latham CM, Keeble AR, Thomas NT, Owen AM, Reeves KA, Long DE, Patrick M, Gonzalez-Velez S, Abed V, Annamalai RT, Jacobs C, Conley CE, Hawk GS, Stone AV, Fry JL, Thompson KL, Johnson DL, Noehren B, Fry CS. GDF8 inhibition enhances musculoskeletal recovery and mitigates posttraumatic osteoarthritis following joint injury. SCIENCE ADVANCES 2023; 9:eadi9134. [PMID: 38019905 PMCID: PMC10686569 DOI: 10.1126/sciadv.adi9134] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 10/27/2023] [Indexed: 12/01/2023]
Abstract
Musculoskeletal disorders contribute substantially to worldwide disability. Anterior cruciate ligament (ACL) tears result in unresolved muscle weakness and posttraumatic osteoarthritis (PTOA). Growth differentiation factor 8 (GDF8) has been implicated in the pathogenesis of musculoskeletal degeneration following ACL injury. We investigated GDF8 levels in ACL-injured human skeletal muscle and serum and tested a humanized monoclonal GDF8 antibody against a placebo in a mouse model of PTOA (surgically induced ACL tear). In patients, muscle GDF8 was predictive of atrophy, weakness, and periarticular bone loss 6 months following surgical ACL reconstruction. In mice, GDF8 antibody administration substantially mitigated muscle atrophy, weakness, and fibrosis. GDF8 antibody treatment rescued the skeletal muscle and articular cartilage transcriptomic response to ACL injury and attenuated PTOA severity and deficits in periarticular bone microarchitecture. Furthermore, GDF8 genetic deletion neutralized musculoskeletal deficits in response to ACL injury. Our findings support an opportunity for rapid targeting of GDF8 to enhance functional musculoskeletal recovery and mitigate the severity of PTOA after injury.
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Affiliation(s)
- Camille R. Brightwell
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Athletic Training and Clinical Nutrition, College of Health Sciences, University of Kentucky, Lexington, KY, USA
| | - Christine M. Latham
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Athletic Training and Clinical Nutrition, College of Health Sciences, University of Kentucky, Lexington, KY, USA
| | - Alexander R. Keeble
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Athletic Training and Clinical Nutrition, College of Health Sciences, University of Kentucky, Lexington, KY, USA
| | - Nicholas T. Thomas
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Athletic Training and Clinical Nutrition, College of Health Sciences, University of Kentucky, Lexington, KY, USA
| | - Allison M. Owen
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Athletic Training and Clinical Nutrition, College of Health Sciences, University of Kentucky, Lexington, KY, USA
| | - Kelsey A. Reeves
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, KY, USA
| | - Douglas E. Long
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - Matthew Patrick
- Department of Biomedical Engineering, College of Engineering, University of Kentucky, Lexington, KY, USA
| | | | - Varag Abed
- Department of Orthopaedic Surgery and Sports Medicine, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Ramkumar T. Annamalai
- Department of Biomedical Engineering, College of Engineering, University of Kentucky, Lexington, KY, USA
| | - Cale Jacobs
- Department of Orthopaedic Surgery and Sports Medicine, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Caitlin E. Conley
- Department of Orthopaedic Surgery and Sports Medicine, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Gregory S. Hawk
- Department of Statistics, College of Arts and Sciences, University of Kentucky, Lexington, KY, USA
| | - Austin V. Stone
- Department of Orthopaedic Surgery and Sports Medicine, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Jean L. Fry
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Athletic Training and Clinical Nutrition, College of Health Sciences, University of Kentucky, Lexington, KY, USA
| | - Katherine L. Thompson
- Department of Statistics, College of Arts and Sciences, University of Kentucky, Lexington, KY, USA
| | - Darren L. Johnson
- Department of Orthopaedic Surgery and Sports Medicine, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Brian Noehren
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, KY, USA
- Department of Orthopaedic Surgery and Sports Medicine, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Christopher S. Fry
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Athletic Training and Clinical Nutrition, College of Health Sciences, University of Kentucky, Lexington, KY, USA
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19
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Wellette-Hunsucker AG, Leszczynski EC, Visker JR, Pritchard A, Mcpeek AC, Quinn MA, Wen Y, Albathi F, Slade JM, Ferguson DP. The Effect of Downhill Running on Quadriceps Muscle in Growth-Restricted Mice. Med Sci Sports Exerc 2023; 55:2160-2169. [PMID: 37486763 PMCID: PMC10805954 DOI: 10.1249/mss.0000000000003259] [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] [Indexed: 07/25/2023]
Abstract
INTRODUCTION Growth restriction (GR) reduces ribosome abundance and skeletal muscle mass in mice. A reduction in skeletal muscle mass increases the risk of frailty and is associated with high morbidity and mortality rates. As eccentric type exercise increases muscle mass, this investigation aimed to determine if eccentric loading of skeletal muscle via downhill running (DHR) increased muscle mass in GR mice. METHODS Mice were growth-restricted either gestational undernutrition (GUN, n = 8 litters), postnatal undernutrition (PUN, n = 8 litters), or were not restricted (CON, n = 8 litters) via a validated cross-fostering nutritive model. On postnatal day (PN) 21, all mice were weaned to a healthy diet, isolating the period of GR to early life as seen in humans. At PN45, mice were assigned to either a DHR (CON, n = 4 litters; GUN, n = 4 litters; PUN, n = 4 litters) or sedentary (SED: CON, n = 4 litters; GUN, n = 4 litters; PUN, n = 4 litters) group. Downhill running (16% decline: 18 m·min -1 ) was performed in 30-min bouts, three times per week, for 12 wk on a rodent treadmill. At PN129, the quadriceps femoris was dissected and evaluated for mass, myofiber size and type, and molecular markers of growth. RESULTS Following training, CON-DHR mice having larger cells than CON-SED, GUN-SED, PUN-SED, and PUN-DHR mice ( P < 0.05). The PUN group (as compared with CON) had reduced body mass ( P < 0.001), upstream binding factor abundance ( P = 0.012), phosphor-mTOR ( P < 0.001), and quadriceps mass ( P = 0.02). The GUN and PUN groups had increased MuRF1 abundance ( P < 0.001) compared with CON ( P < 0.001). CONCLUSIONS The blunted response to training suggests GR mice may have anabolic resistance when exposed to eccentric type exercise.
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Affiliation(s)
- Austin G. Wellette-Hunsucker
- Department of Kinesiology, Michigan State University, East Lansing, MI
- Deparment of Physiology, College of Medicine, University of Kentucky, Lexington, KY
- Center for Muscle Biology, University of Kentucky, Lexington, KY
| | | | - Joseph R. Visker
- Department of Kinesiology, Michigan State University, East Lansing, MI
- The Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT
| | - Abby Pritchard
- Department of Animal Science, Michigan State University, East Lansing, MI
- Regulatory and Nutritional Compliance, Mars Petcare, Franklin, TN
| | - Ashley C. Mcpeek
- Department of Kinesiology, Michigan State University, East Lansing, MI
| | - Melissa A. Quinn
- Department of Kinesiology, Michigan State University, East Lansing, MI
| | - Yuan Wen
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, KY
- Center for Muscle Biology, University of Kentucky, Lexington, KY
| | - Fatmah Albathi
- Department of Pharmacology and Nutritional Sciences, College of Medicine, University of Kentucky, Lexington, KY
| | - Jill M. Slade
- Department of Radiology, Michigan State University, East Lansing, MI
| | - David P. Ferguson
- Department of Kinesiology, Michigan State University, East Lansing, MI
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20
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Long DE, Mantuano AJ, Confides AL, Miller BF, Kern PA, Butterfield TA, Dupont-Versteegden EE. Short-term repeated human biopsy sampling contributes to changes in muscle morphology and higher outcome variability. J Appl Physiol (1985) 2023; 135:1403-1414. [PMID: 37705447 PMCID: PMC10979834 DOI: 10.1152/japplphysiol.00441.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 09/12/2023] [Accepted: 09/12/2023] [Indexed: 09/15/2023] Open
Abstract
Changes in skeletal muscle are an important aspect of overall health. The collection of human muscle to study cellular and molecular processes for research requires a needle biopsy procedure which, in itself, can induce changes in the tissue. To investigate the effect of repeat tissue sampling, we collected skeletal muscle biopsy samples from vastus lateralis separated by 7 days. Cellular infiltrate, central nucleation, enlarged extracellular matrix, and rounding of muscle fibers were used as indices to define muscle damage, and we found that 16/26 samples (61.5%) revealed at least two of these symptoms in the secondary biopsy. The presence of damage influenced outcome measures usually obtained in human biopsies. Damaged muscle showed an increase in the number of small fibers even though average fiber and fiber type-specific cross-sectional area (CSA) were not different. This included higher numbers of embryonic myosin heavy chain-positive fibers (P = 0.001) as well as elevated satellite cell number (P = 0.02) in the damaged areas and higher variability in satellite cell count in the total area (P = 0.04). Collagen content was higher in damaged (P = 0.0003) as well as nondamaged areas (P = 0.05) of the muscle sections of the damaged compared with the nondamaged group. Myofibrillar protein and ribonucleic acid (RNA) fractional synthesis rates were not significantly different between the damaged compared with the nondamaged group. Results indicate that common outcomes as well as outcome variability in human muscle tissue are affected by previous biopsies. Therefore, the extent of potential damage should be assessed when performing repeated biopsies.NEW & NOTEWORTHY Indices of damage can be found in repeated biopsy samples of nonintervened control legs. Variables, directly and not directly related to muscle damage or regeneration, were compromised in second biopsy. There is a need to determine potential damage within muscle tissue when repeated muscle sampling is part of the study design. Muscle biopsy sampling may be a source of increased heterogeneity in human muscle data.
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Affiliation(s)
- Douglas E Long
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, Kentucky, United States
- Center for Muscle Biology, University of Kentucky, Lexington, Kentucky, United States
| | - Alessandra J Mantuano
- Center for Muscle Biology, University of Kentucky, Lexington, Kentucky, United States
| | - Amy L Confides
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, Kentucky, United States
- Center for Muscle Biology, University of Kentucky, Lexington, Kentucky, United States
| | - Benjamin F Miller
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States
- Oklahoma City VA Medical Center, Oklahoma City, Oklahoma, United States
| | - Philip A Kern
- Division of Endocrinology, Department of Internal Medicine, Barnstable Brown Diabetes and Obesity Center, University of Kentucky, Lexington, Kentucky, United States
| | - Timothy A Butterfield
- Center for Muscle Biology, University of Kentucky, Lexington, Kentucky, United States
- Department of Athletic Training and Clinical Nutrition, College of Health Sciences, University of Kentucky, Lexington, Kentucky, United States
| | - Esther E Dupont-Versteegden
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, Kentucky, United States
- Center for Muscle Biology, University of Kentucky, Lexington, Kentucky, United States
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21
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Burke BI, Goh J, Albathi FA, Valentino TR, Nolt GL, Joshi JK, Dungan CM, Johnson LA, Wen Y, Ismaeel A, McCarthy JJ. ApoE isoform does not influence skeletal muscle regeneration in adult mice. Front Physiol 2023; 14:1302695. [PMID: 38074327 PMCID: PMC10702509 DOI: 10.3389/fphys.2023.1302695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 11/10/2023] [Indexed: 02/12/2024] Open
Abstract
Introduction: Apolipoprotein E (ApoE) has been shown to be necessary for proper skeletal muscle regeneration. Consistent with this finding, single-cell RNA-sequencing analyses of skeletal muscle stem cells (MuSCs) revealed that Apoe is a top marker of quiescent MuSCs that is downregulated upon activation. The purpose of this study was to determine if muscle regeneration is altered in mice which harbor one of the three common human ApoE isoforms, referred to as ApoE2, E3 and E4. Methods: Histomorphometric analyses were employed to assess muscle regeneration in ApoE2, E3, and E4 mice after 14 days of recovery from barium chloride-induced muscle damage in vivo, and primary MuSCs were isolated to assess proliferation and differentiation of ApoE2, E3, and E4 MuSCs in vitro. Results: There was no difference in the basal skeletal muscle phenotype of ApoE isoforms as evaluated by section area, myofiber cross-sectional area (CSA), and myonuclear and MuSC abundance per fiber. Although there were no differences in fiber-type frequency in the soleus, Type IIa relative frequency was significantly lower in plantaris muscles of ApoE4 mice compared to ApoE3. Moreover, ApoE isoform did not influence muscle regeneration as assessed by fiber frequency, fiber CSA, and myonuclear and MuSC abundance. Finally, there were no differences in the proliferative capacity or myogenic differentiation potential of MuSCs between any ApoE isoform. Discussion: Collectively, these data indicate nominal effects of ApoE isoform on the ability of skeletal muscle to regenerate following injury or the in vitro MuSC phenotype.
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Affiliation(s)
- Benjamin I. Burke
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, United States
- Center for Muscle Biology, University of Kentucky, Lexington, KY, United States
| | - Jensen Goh
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, United States
- Center for Muscle Biology, University of Kentucky, Lexington, KY, United States
| | - Fatmah A. Albathi
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, United States
- Center for Muscle Biology, University of Kentucky, Lexington, KY, United States
| | | | - Georgia L. Nolt
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, United States
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, United States
| | - Jai K. Joshi
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, United States
- Center for Muscle Biology, University of Kentucky, Lexington, KY, United States
| | - Cory M. Dungan
- Department of Health, Human Performance, and Recreation, Robbins College of Health and Human Sciences, Baylor University, Waco, TX, United States
| | - Lance A. Johnson
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, United States
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, United States
| | - Yuan Wen
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, United States
- Center for Muscle Biology, University of Kentucky, Lexington, KY, United States
- Division of Biomedical Informatics, Department of Internal Medicine, College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Ahmed Ismaeel
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, United States
- Center for Muscle Biology, University of Kentucky, Lexington, KY, United States
| | - John J. McCarthy
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, United States
- Center for Muscle Biology, University of Kentucky, Lexington, KY, United States
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22
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Bunn RC, Adatorwovor R, Smith RR, Ray PD, Fields SE, Keeble AR, Fry CS, Uppuganti S, Nyman JS, Fowlkes JL, Kalaitzoglou E. Pharmacologic Inhibition of Myostatin With a Myostatin Antibody Improves the Skeletal Muscle and Bone Phenotype of Male Insulin-Deficient Diabetic Mice. JBMR Plus 2023; 7:e10833. [PMID: 38025035 PMCID: PMC10652179 DOI: 10.1002/jbm4.10833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 09/18/2023] [Accepted: 10/01/2023] [Indexed: 12/01/2023] Open
Abstract
Type 1 diabetes (T1D) is associated with low bone and muscle mass, increased fracture risk, and impaired skeletal muscle function. Myostatin, a myokine that is systemically elevated in humans with T1D, negatively regulates muscle mass and bone formation. We investigated whether pharmacologic myostatin inhibition in a mouse model of insulin-deficient, streptozotocin (STZ)-induced diabetes is protective for bone and skeletal muscle. DBA/2J male mice were injected with low-dose STZ (diabetic) or vehicle (non-diabetic). Subsequently, insulin or palmitate Linbits were implanted and myostatin (REGN647-MyoAb) or control (REGN1945-ConAb) antibody was administered for 8 weeks. Body composition and contractile muscle function were assessed in vivo. Systemic myostatin, P1NP, CTX-I, and glycated hemoglobin (HbA1c) were quantified, and gastrocnemii were weighed and analyzed for muscle fiber composition and gene expression of selected genes. Cortical and trabecular parameters were analyzed (micro-computed tomography evaluations of femur) and cortical bone strength was assessed (three-point bending test of femur diaphysis). In diabetic mice, the combination of insulin/MyoAb treatment resulted in significantly higher lean mass and gastrocnemius weight compared with MyoAb or insulin treatment alone. Similarly, higher raw torque was observed in skeletal muscle of insulin/MyoAb-treated diabetic mice compared with MyoAb or insulin treatment. Additionally, muscle fiber cross-sectional area (CSA) was lower with diabetes and the combination treatment with insulin/MyoAb significantly improved CSA in type II fibers. Insulin, MyoAb, or insulin/MyoAb treatment improved several parameters of trabecular architecture (eg, bone volume fraction [BV/TV], trabecular connectivity density [Conn.D]) and cortical structure (eg, cortical bone area [Ct. Ar.], minimum moment of inertia [Imin]) in diabetic mice. Lastly, cortical bone biomechanical properties (stiffness and yield force) were also improved with insulin or MyoAb treatment. In conclusion, pharmacologic myostatin inhibition is beneficial for muscle mass, muscle function, and bone properties in this mouse model of T1D and its effects are both independent and additive to the positive effects of insulin. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- R Clay Bunn
- Department of Pediatrics and Barnstable Brown Diabetes CenterUniversity of KentuckyLexingtonKYUSA
| | - Reuben Adatorwovor
- Department of Biostatistics, College of Public HealthUniversity of KentuckyLexingtonKYUSA
| | - Rebecca R Smith
- Sanders‐Brown Center on AgingUniversity of KentuckyLexingtonKYUSA
| | - Philip D Ray
- Department of PediatricsUniversity of KentuckyLexingtonKYUSA
| | - Sarah E Fields
- College of Agriculture, Food and EnvironmentUniversity of KentuckyLexingtonKYUSA
| | | | | | - Sasidhar Uppuganti
- Department of Orthopaedic SurgeryVanderbilt University Medical CenterNashvilleTNUSA
| | - Jeffry S Nyman
- Department of Orthopaedic SurgeryVanderbilt University Medical CenterNashvilleTNUSA
- Department of Veterans AffairsTennessee Valley Healthcare SystemNashvilleTNUSA
| | - John L Fowlkes
- Department of Pediatrics and Barnstable Brown Diabetes CenterUniversity of KentuckyLexingtonKYUSA
| | - Evangelia Kalaitzoglou
- Department of Pediatrics and Barnstable Brown Diabetes CenterUniversity of KentuckyLexingtonKYUSA
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23
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Kugler BA, Lourie J, Berger N, Lin N, Nguyen P, DosSantos E, Ali A, Sesay A, Rosen HG, Kalemba B, Hendricks GM, Houmard JA, Sesaki H, Gona P, You T, Yan Z, Zou K. Partial skeletal muscle-specific Drp1 knockout enhances insulin sensitivity in diet-induced obese mice, but not in lean mice. Mol Metab 2023; 77:101802. [PMID: 37690520 PMCID: PMC10511484 DOI: 10.1016/j.molmet.2023.101802] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 08/22/2023] [Accepted: 09/05/2023] [Indexed: 09/12/2023] Open
Abstract
OBJECTIVE Dynamin-related protein 1 (Drp1) is the key regulator of mitochondrial fission. We and others have reported a strong correlation between enhanced Drp1 activity and impaired skeletal muscle insulin sensitivity. This study aimed to determine whether Drp1 directly regulates skeletal muscle insulin sensitivity and whole-body glucose homeostasis. METHODS We employed tamoxifen-inducible skeletal muscle-specific heterozygous Drp1 knockout mice (mDrp1+/-). Male mDrp1+/- and wildtype (WT) mice were fed with either a high-fat diet (HFD) or low-fat diet (LFD) for four weeks, followed by tamoxifen injections for five consecutive days, and remained on their respective diet for another four weeks. In addition, we used primary human skeletal muscle cells (HSkMC) from lean, insulin-sensitive, and severely obese, insulin-resistant humans and transfected the cells with either a Drp1 shRNA (shDrp1) or scramble shRNA construct. Skeletal muscle and whole-body insulin sensitivity, skeletal muscle insulin signaling, mitochondrial network morphology, respiration, and H2O2 production were measured. RESULTS Partial deletion of the Drp1 gene in skeletal muscle led to improved whole-body glucose tolerance and insulin sensitivity (P < 0.05) in diet-induced obese, insulin-resistant mice but not in lean mice. Analyses of mitochondrial structure and function revealed that the partial deletion of the Drp1 gene restored mitochondrial dynamics, improved mitochondrial morphology, and reduced mitochondrial Complex I- and II-derived H2O2 (P < 0.05) under the condition of diet-induced obesity. In addition, partial deletion of Drp1 in skeletal muscle resulted in elevated circulating FGF21 (P < 0.05) and in a trend towards increase of FGF21 expression in skeletal muscle tissue (P = 0.095). In primary myotubes derived from severely obese, insulin-resistant humans, ShRNA-induced-knockdown of Drp1 resulted in enhanced insulin signaling, insulin-stimulated glucose uptake and reduced cellular reactive oxygen species (ROS) content compared to the shScramble-treated myotubes from the same donors (P < 0.05). CONCLUSION These data demonstrate that partial loss of skeletal muscle-specific Drp1 expression is sufficient to improve whole-body glucose homeostasis and insulin sensitivity under obese, insulin-resistant conditions, which may be, at least in part, due to reduced mitochondrial H2O2 production. In addition, our findings revealed divergent effects of Drp1 on whole-body metabolism under lean healthy or obese insulin-resistant conditions in mice.
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Affiliation(s)
- Benjamin A Kugler
- Department of Exercise and Health Sciences, Robert and Donna Manning College of Nursing and Health Sciences, University of Massachusetts Boston, Boston, MA, USA
| | - Jared Lourie
- Department of Exercise and Health Sciences, Robert and Donna Manning College of Nursing and Health Sciences, University of Massachusetts Boston, Boston, MA, USA
| | - Nicolas Berger
- Department of Exercise and Health Sciences, Robert and Donna Manning College of Nursing and Health Sciences, University of Massachusetts Boston, Boston, MA, USA
| | - Nana Lin
- Department of Exercise and Health Sciences, Robert and Donna Manning College of Nursing and Health Sciences, University of Massachusetts Boston, Boston, MA, USA
| | - Paul Nguyen
- Department of Exercise and Health Sciences, Robert and Donna Manning College of Nursing and Health Sciences, University of Massachusetts Boston, Boston, MA, USA
| | - Edzana DosSantos
- Department of Exercise and Health Sciences, Robert and Donna Manning College of Nursing and Health Sciences, University of Massachusetts Boston, Boston, MA, USA
| | - Abir Ali
- Department of Biology, University of Massachusetts Boston, Boston, MA, USA
| | - Amira Sesay
- Department of Biology, University of Massachusetts Boston, Boston, MA, USA
| | - H Grace Rosen
- Department of Biology, University of Massachusetts Boston, Boston, MA, USA
| | - Baby Kalemba
- Department of Exercise and Health Sciences, Robert and Donna Manning College of Nursing and Health Sciences, University of Massachusetts Boston, Boston, MA, USA
| | - Gregory M Hendricks
- Department of Radiology, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Joseph A Houmard
- Department of Kinesiology, East Carolina University, Greenville, NC, USA; Human Performance Laboratory, East Carolina University, Greenville, NC, USA
| | - Hiromi Sesaki
- Department of Cell Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Philimon Gona
- Department of Exercise and Health Sciences, Robert and Donna Manning College of Nursing and Health Sciences, University of Massachusetts Boston, Boston, MA, USA
| | - Tongjian You
- Department of Exercise and Health Sciences, Robert and Donna Manning College of Nursing and Health Sciences, University of Massachusetts Boston, Boston, MA, USA
| | - Zhen Yan
- Fralin Biomedical Research Institute Center for Exercise Medicine Research, Virginia Tech Carilion, Roanoke, VA, USA; Department of Human Nutrition, Foods, and Exercise, College of Agriculture and Life Sciences, Virginia Tech, Blacksburg, VA, USA
| | - Kai Zou
- Department of Exercise and Health Sciences, Robert and Donna Manning College of Nursing and Health Sciences, University of Massachusetts Boston, Boston, MA, USA.
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24
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Wang K, Frey N, Garcia A, Man K, Yang Y, Gualerzi A, Clemens ZJ, Bedoni M, LeDuc PR, Ambrosio F. Nanotopographical Cues Tune the Therapeutic Potential of Extracellular Vesicles for the Treatment of Aged Skeletal Muscle Injuries. ACS NANO 2023; 17:19640-19651. [PMID: 37797946 PMCID: PMC10603813 DOI: 10.1021/acsnano.3c02269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 09/22/2023] [Indexed: 10/07/2023]
Abstract
Skeletal muscle regeneration relies on the tightly temporally regulated lineage progression of muscle stem/progenitor cells (MPCs) from activation to proliferation and, finally, differentiation. However, with aging, MPC lineage progression is disrupted and delayed, ultimately causing impaired muscle regeneration. Extracellular vesicles (EVs) have attracted broad attention as next-generation therapeutics for promoting tissue regeneration. As a next step toward clinical translation, strategies to manipulate EV effects on downstream cellular targets are needed. Here, we developed an engineering strategy to tune the therapeutic potential of EVs using nanotopographical cues. We found that EVs released by young MPCs cultured on flat substrates (fEVs) promoted the proliferation of aged MPCs while EVs released by MPCs cultured on nanogratings (nEVs) promoted myogenic differentiation. We then employed a bioengineered 3D muscle aging model to optimize the administration protocol and test the therapeutic potential of fEVs and nEVs in a high-throughput manner. We found that the sequential administration first of fEVs during the phase of MPC proliferative expansion (i.e., 1 day after injury) followed by nEV administration at the stage of MPC differentiation (i.e., 3 days after injury) enhanced aged muscle regeneration to a significantly greater extent than fEVs and nEVs delivered either in isolation or mixed. The beneficial effects of the sequential EV treatment strategy were further validated in vivo, as evidenced by increased myofiber size and improved functional recovery. Collectively, our study demonstrates the ability of topographical cues to tune EV therapeutic potential and highlights the importance of optimizing the EV administration strategy to accelerate aged skeletal muscle regeneration.
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Affiliation(s)
- Kai Wang
- Discovery
Center for Musculoskeletal Recovery, Schoen
Adams Research Institute at Spaulding, Charlestown, Massachusetts 02129, United States
- Department
of Physical Medicine & Rehabilitation, Harvard Medical School, Boston, Massachusetts 02115, United States
- Department
of Physical Medicine & Rehabilitation, Spaulding Rehabilitation Hospital, Charlestown, Massachusetts 02129, United States
- Department
of Physical Medicine & Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, United States
| | - Nolan Frey
- Department
of Biological Sciences, Carnegie Mellon
University, Pittsburgh, Pennsylvania 15213, United States
| | - Andres Garcia
- Department
of Mechanical Engineering, Carnegie Mellon
University, Pittsburgh, Pennsylvania 15213, United States
| | - Kun Man
- Department
of Biomedical Engineering, University of
North Texas, Denton, Texas 76207, United States
| | - Yong Yang
- Department
of Biomedical Engineering, University of
North Texas, Denton, Texas 76207, United States
| | - Alice Gualerzi
- IRCCS
Fondazione Don Carlo Gnocchi ONLUS, Milan 20148, Italy
| | - Zachary J. Clemens
- Department
of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, United States
| | - Marzia Bedoni
- IRCCS
Fondazione Don Carlo Gnocchi ONLUS, Milan 20148, Italy
| | - Philip R. LeDuc
- Department
of Biological Sciences, Carnegie Mellon
University, Pittsburgh, Pennsylvania 15213, United States
- Department
of Mechanical Engineering, Carnegie Mellon
University, Pittsburgh, Pennsylvania 15213, United States
- Department
of Computational Biology, Carnegie Mellon
University, Pittsburgh, Pennsylvania 15213, United States
- Department
of Biomedical Engineering, Carnegie Mellon
University, Pittsburgh, Pennsylvania 15213, United States
- Department
of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Fabrisia Ambrosio
- Discovery
Center for Musculoskeletal Recovery, Schoen
Adams Research Institute at Spaulding, Charlestown, Massachusetts 02129, United States
- Department
of Physical Medicine & Rehabilitation, Harvard Medical School, Boston, Massachusetts 02115, United States
- Department
of Physical Medicine & Rehabilitation, Spaulding Rehabilitation Hospital, Charlestown, Massachusetts 02129, United States
- Department
of Physical Medicine & Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, United States
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25
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Mayer KP, Kosmac K, Wen Y, Parry SM, Dhar S, Foster S, Starck J, Montgomery-Yates AA, Dupont-Versteegden EE, Kalema AG. Construct and criterion validity of muscle ultrasonography for assessment of skeletal muscle in patients recovering from COVID-19. Front Physiol 2023; 14:1231538. [PMID: 37936579 PMCID: PMC10625915 DOI: 10.3389/fphys.2023.1231538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 10/10/2023] [Indexed: 11/09/2023] Open
Abstract
Background: The purpose was to investigate the content, construct, and criterion validity of muscle ultrasound in a mixed cohort of participants recovering from mild and critical COVID-19. Methods: A secondary analysis of a prospective cross-sectional study was conducted on data obtained from a battery of muscle and physical function assessments including a muscle biopsy and muscle ultrasonography (US). Rectus femoris (RF) muscle thickness (mT), quadricep complex (QC) mT, RF muscle cross-sectional area (CSA) using 2D freeform trace and estimated from Feret's diameter, and RF echo intensity (EI) were assessed with US. Muscle fiber CSA, fiber type, protein content in muscle fibers, extracellular matrix content (ECM; wheat-germ agglutin), and percent area of collagen in ECM (picrosirius red) were examined from vastus lateralis muscle biopsies. Spearman rho correlations (r) were performed to assess validity of ultrasound parameters. Results: Thirty-three individuals participated including 11 patients surviving critical COVID-19, 15 individuals recovering from mild-COVID, and 7 controls. There were several significant correlations between RF mT, QC mT, RF CSA, and RF EI with age, comorbid burden, body-mass index, and measures of muscle strength, muscle power, and physical function (range r = 0.35-0.83). RF Feret's CSA correlated to CSA of type II muscle fibers (r = 0.41, p = 0.022) and the average size of all muscle fibers (r = 0.39, p = 0.031). RF EI was correlated with collagen in muscle ECM (r = 0.53, p = 0.003) and protein content in muscle tissue (r = -0.52, p = 0.012). Conclusion: Muscle size and quality measured using US has moderate content and construct validity, and to lesser extent, fair to moderate criterion validity in a mixed cohort of individuals recovering from COVID. Muscle ultrasound quality (EI) appears to be sensitive at detecting muscle dysfunction as it is associated with strength, power, physical function, and collagen distribution in a mixed group of individuals recovering from COVID-19.
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Affiliation(s)
- Kirby P. Mayer
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, KY, United States
- Center for Muscle Biology, University of Kentucky, Lexington, KY, United States
| | - Kate Kosmac
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, KY, United States
- Center for Muscle Biology, University of Kentucky, Lexington, KY, United States
| | - Yuan Wen
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, KY, United States
| | - Selina M. Parry
- Department of Physiotherapy, School of Health Sciences, The University of Melbourne, Melbourne, VIC, Australia
| | - Sanjay Dhar
- Division of Pulmonary, Critical Care, and Sleep Medicine, College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Sarah Foster
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, KY, United States
| | - Jonathan Starck
- Department of Biology, College of Arts and Sciences, University of Kentucky, Lexington, KY, United States
| | - Ashley A. Montgomery-Yates
- Division of Pulmonary, Critical Care, and Sleep Medicine, College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Esther E. Dupont-Versteegden
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, KY, United States
- Center for Muscle Biology, University of Kentucky, Lexington, KY, United States
| | - Anna G. Kalema
- Division of Pulmonary, Critical Care, and Sleep Medicine, College of Medicine, University of Kentucky, Lexington, KY, United States
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26
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Fuqua JD, Lawrence MM, Hettinger ZR, Borowik AK, Brecheen PL, Szczygiel MM, Abbott CB, Peelor FF, Confides AL, Kinter M, Bodine SC, Dupont‐Versteegden EE, Miller BF. Impaired proteostatic mechanisms other than decreased protein synthesis limit old skeletal muscle recovery after disuse atrophy. J Cachexia Sarcopenia Muscle 2023; 14:2076-2089. [PMID: 37448295 PMCID: PMC10570113 DOI: 10.1002/jcsm.13285] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 04/10/2023] [Accepted: 05/22/2023] [Indexed: 07/15/2023] Open
Abstract
BACKGROUND Skeletal muscle mass and strength diminish during periods of disuse but recover upon return to weight bearing in healthy adults but are incomplete in old muscle. Efforts to improve muscle recovery in older individuals commonly aim at increasing myofibrillar protein synthesis via mammalian target of rapamycin (mTOR) stimulation despite evidence demonstrating that old muscle has chronically elevated levels of mammalian target of rapamycin complex 1 (mTORC1) activity. We hypothesized that protein synthesis is higher in old muscle than adult muscle, which contributes to a proteostatic stress that impairs recovery. METHODS We unloaded hindlimbs of adult (10-month) and old (28-month) F344BN rats for 14 days to induce atrophy, followed by reloading up to 60 days with deuterium oxide (D2 O) labelling to study muscle regrowth and proteostasis. RESULTS We found that old muscle has limited recovery of muscle mass during reloading despite having higher translational capacity and myofibrillar protein synthesis (0.029 k/day ± 0.002 vs. 0.039 k/day ± 0.002, P < 0.0001) than adult muscle. We showed that collagen protein synthesis was not different (0.005 k (1/day) ± 0.0005 vs. 0.004 k (1/day) ± 0.0005, P = 0.15) in old compared to adult, but old muscle had higher collagen concentration (4.5 μg/mg ± 1.2 vs. 9.8 μg/mg ± 0.96, P < 0.01), implying that collagen breakdown was slower in old muscle than adult muscle. This finding was supported by old muscle having more insoluble collagen (4.0 ± 1.1 vs. 9.2 ± 0.9, P < 0.01) and an accumulation of advanced glycation end products (1.0 ± 0.06 vs. 1.5 ± 0.08, P < 0.001) than adult muscle during reloading. Limited recovery of muscle mass during reloading is in part due to higher protein degradation (0.017 1/t ± 0.002 vs. 0.028 1/t ± 0.004, P < 0.05) and/or compromised proteostasis as evidenced by accumulation of ubiquitinated insoluble proteins (1.02 ± 0.06 vs. 1.22 ± 0.06, P < 0.05). Last, we showed that synthesis of individual proteins related to protein folding/refolding, protein degradation and neural-related biological processes was higher in old muscle during reloading than adult muscle. CONCLUSIONS Our data suggest that the failure of old muscle to recover after disuse is not due to limitations in the ability to synthesize myofibrillar proteins but because of other impaired proteostatic mechanisms (e.g., protein folding and degradation). These data provide novel information on individual proteins that accumulate in protein aggregates after disuse and certain biological processes such as protein folding and degradation that likely play a role in impaired recovery. Therefore, interventions to enhance regrowth of old muscle after disuse should be directed towards the identified impaired proteostatic mechanisms and not aimed at increasing protein synthesis.
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Affiliation(s)
- Jordan D. Fuqua
- Aging & Metabolism Research ProgramOklahoma Medical Research FoundationOklahoma CityOKUSA
| | - Marcus M. Lawrence
- Aging & Metabolism Research ProgramOklahoma Medical Research FoundationOklahoma CityOKUSA
- Department of Kinesiology and Outdoor RecreationSouthern Utah UniversityCedar CityUTUSA
| | - Zachary R. Hettinger
- Department of Physical Therapy, College of Health SciencesUniversity of KentuckyLexingtonKYUSA
- Center for Muscle BiologyUniversity of KentuckyLexingtonKYUSA
| | - Agnieszka K. Borowik
- Aging & Metabolism Research ProgramOklahoma Medical Research FoundationOklahoma CityOKUSA
| | - Parker L. Brecheen
- Aging & Metabolism Research ProgramOklahoma Medical Research FoundationOklahoma CityOKUSA
| | - Marcelina M. Szczygiel
- Aging & Metabolism Research ProgramOklahoma Medical Research FoundationOklahoma CityOKUSA
| | - Claire B. Abbott
- Aging & Metabolism Research ProgramOklahoma Medical Research FoundationOklahoma CityOKUSA
| | - Frederick F. Peelor
- Aging & Metabolism Research ProgramOklahoma Medical Research FoundationOklahoma CityOKUSA
| | - Amy L. Confides
- Department of Physical Therapy, College of Health SciencesUniversity of KentuckyLexingtonKYUSA
- Center for Muscle BiologyUniversity of KentuckyLexingtonKYUSA
| | - Michael Kinter
- Aging & Metabolism Research ProgramOklahoma Medical Research FoundationOklahoma CityOKUSA
| | - Sue C. Bodine
- Aging & Metabolism Research ProgramOklahoma Medical Research FoundationOklahoma CityOKUSA
- Department of Internal MedicineUniversity of IowaIowa CityIAUSA
- Fraternal Order of Eagles Diabetes Research CenterUniversity of IowaIowa CityIAUSA
- Iowa City Veterans Affairs Medical CenterIowa CityIAUSA
| | - Esther E. Dupont‐Versteegden
- Department of Physical Therapy, College of Health SciencesUniversity of KentuckyLexingtonKYUSA
- Center for Muscle BiologyUniversity of KentuckyLexingtonKYUSA
| | - Benjamin F. Miller
- Aging & Metabolism Research ProgramOklahoma Medical Research FoundationOklahoma CityOKUSA
- Oklahoma City Veterans Affairs Medical CenterOklahoma CityOKUSA
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27
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Vanmunster M, Rojo-Garcia AV, Pacolet A, Jonkers I, Koppo K, Lories R, Suhr F. Prolonged mechanical muscle loading increases mechanosensor gene and protein levels and causes a moderate fast-to-slow fiber type switch in mice. J Appl Physiol (1985) 2023; 135:918-931. [PMID: 37675473 DOI: 10.1152/japplphysiol.00204.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 08/30/2023] [Accepted: 08/30/2023] [Indexed: 09/08/2023] Open
Abstract
Mechanosensing and subsequent mechanotransduction are indispensable for muscle plasticity. Nevertheless, a scarcity of literature exists regarding an all-encompassing understanding of the muscle mechanosensing machinery's response to prolonged loading, especially in conditions that resemble a natural physiological state of skeletal muscle. This study aimed to comprehensively explore the effects of prolonged mechanical loading on mechanosensitive components, skeletal muscle characteristics, and metabolism-related gene clusters. Twenty male C57BL/6J mice were randomly divided into two groups: control and prolonged mechanical loading. To induce prolonged mechanical loading on the triceps brachii (TRI) and biceps brachii (BIC) muscles, a 14-day period of tail suspension was implemented. In TRI only, prolonged mechanical loading caused a mild fast-to-slow fiber type shift together with increased mechanosensor gene and protein levels. It also increased transcription factors associated with slow muscle fibers while decreasing those related to fast-type muscle gene expression. Succinate dehydrogenase activity, a marker of muscle oxidative capacity, and genes involved in oxidative and mitochondrial turnover increased, whereas glycolytic-related genes decreased. Moreover, prolonged mechanical loading stimulated markers of muscle protein synthesis. Taken together, our data show a collective muscle-specific increase in mechanosensor gene and protein levels upon a period of prolonged mechanical loading in conditions that reflect a more natural physiological state of skeletal muscle in mice. We provide additional proof-of-concept that prolonged tail suspension-induced loading of the forelimbs triggers a muscle-specific fast-to-slow fiber type switch, and this coincides with increased protein synthesis-related signaling.NEW & NOTEWORTHY This study provides a comprehensive overview of the effects of prolonged loading on mechanosensitive components in conditions that better reflect the natural physiological state of skeletal muscle. Although the muscle mechanosensing machinery has been widely acknowledged for its responsiveness to altered loading, an inclusive understanding of its response to prolonged loading remains scarce. Our results show a fast-to-slow fiber type shift and an upregulation of mechanosensor gene and protein levels following prolonged loading.
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Affiliation(s)
- Mathias Vanmunster
- Department of Movement Sciences, Exercise Physiology Research Group, KU Leuven, Leuven, Belgium
| | | | - Alexander Pacolet
- Department of Movement Sciences, Exercise Physiology Research Group, KU Leuven, Leuven, Belgium
| | - Ilse Jonkers
- Department of Movement Sciences, Human Movement Biomechanics Research Group, KU Leuven, Leuven, Belgium
| | - Katrien Koppo
- Department of Movement Sciences, Exercise Physiology Research Group, KU Leuven, Leuven, Belgium
| | - Rik Lories
- Department of Development and Regeneration, Skeletal Biology and Engineering Research Center, KU Leuven, Leuven, Belgium
| | - Frank Suhr
- Department of Movement Sciences, Exercise Physiology Research Group, KU Leuven, Leuven, Belgium
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28
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Baltrusch S. Automated in-depth fiber and nuclei typing in cross-sectional muscle images can pave the way to a better understanding of skeletal muscle diseases. Acta Physiol (Oxf) 2023; 239:e14031. [PMID: 37551418 DOI: 10.1111/apha.14031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 07/27/2023] [Accepted: 07/30/2023] [Indexed: 08/09/2023]
Affiliation(s)
- Simone Baltrusch
- Institute of Medical Biochemistry and Molecular Biology, University Medicine Rostock and Department Life, Light & Matter, University of Rostock, Rostock, Germany
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29
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Lundquist A, Lázár E, Han NS, Emanuelsson EB, Reitzner SM, Chapman MA, Shirokova V, Alkass K, Druid H, Petri S, Sundberg CJ, Bergmann O. FiNuTyper: Design and validation of an automated deep learning-based platform for simultaneous fiber and nucleus type analysis in human skeletal muscle. Acta Physiol (Oxf) 2023; 239:e13982. [PMID: 37097015 DOI: 10.1111/apha.13982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 03/30/2023] [Accepted: 04/21/2023] [Indexed: 04/26/2023]
Abstract
AIM While manual quantification is still considered the gold standard for skeletal muscle histological analysis, it is time-consuming and prone to investigator bias. To address this challenge, we assembled an automated image analysis pipeline, FiNuTyper (Fiber and Nucleus Typer). METHODS We integrated recently developed deep learning-based image segmentation methods, optimized for unbiased evaluation of fresh and postmortem human skeletal muscle, and utilized SERCA1 and SERCA2 as type-specific myonucleus and myofiber markers after validating them against the traditional use of MyHC isoforms. RESULTS Parameters including cross-sectional area, myonuclei per fiber, myonuclear domain, central myonuclei per fiber, and grouped myofiber ratio were determined in a fiber-type-specific manner, revealing that a large degree of sex- and muscle-related heterogeneity could be detected using the pipeline. Our platform was also tested on pathological muscle tissue (ALS and IBM) and adapted for the detection of other resident cell types (leucocytes, satellite cells, capillary endothelium). CONCLUSION In summary, we present an automated image analysis tool for the simultaneous quantification of myofiber and myonuclear types, to characterize the composition and structure of healthy and diseased human skeletal muscle.
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Affiliation(s)
- August Lundquist
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Enikő Lázár
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Nan S Han
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Eric B Emanuelsson
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Stefan M Reitzner
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
- Department for Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden
| | - Mark A Chapman
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
- Department of Integrated Engineering, University of San Diego, San Diego, USA
| | - Vera Shirokova
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Kanar Alkass
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
- Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden
| | - Henrik Druid
- Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden
| | - Susanne Petri
- Department of Neurology, Hanover Medical School, Hanover, Germany
| | - Carl J Sundberg
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
- Department of Learning, Informatics, Management, and Ethics, Karolinska Institutet, Stockholm, Sweden
| | - Olaf Bergmann
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
- Center for Regenerative Therapies Dresden, Technische Universität Dresden, Dresden, Germany
- Pharmacology and Toxicology, University Medical Center Göttingen (UMG), Göttingen, Germany
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30
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Lima G, Kolliari-Turner A, Wang G, Ho P, Meehan L, Roeszler K, Seto J, Malinsky FR, Karanikolou A, Eichhorn G, Tanisawa K, Ospina-Betancurt J, Hamilton B, Kumi PYO, Shurlock J, Skiadas V, Twycross-Lewis R, Kilduff L, Guppy FM, North K, Pitsiladis Y, Fossati C, Pigozzi F, Borrione P. The MMAAS Project: An Observational Human Study Investigating the Effect of Anabolic Androgenic Steroid Use on Gene Expression and the Molecular Mechanism of Muscle Memory. Clin J Sport Med 2023; 33:e115-e122. [PMID: 35533133 DOI: 10.1097/jsm.0000000000001037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Accepted: 03/20/2022] [Indexed: 02/02/2023]
Abstract
OBJECTIVE It remains unknown whether myonuclei remain elevated post anabolic-androgenic steroid (AAS) usage in humans. Limited data exist on AAS-induced changes in gene expression. DESIGN Cross-sectional/longitudinal. SETTING University. PARTICIPANTS Fifty-six men aged 20 to 42 years. INDEPENDENT VARIABLES Non-resistance-trained (C) or resistance-trained (RT), RT currently using AAS (RT-AS), of which if AAS usage ceased for ≥18 weeks resampled as Returning Participants (RP) or RT previously using AAS (PREV). MAIN OUTCOME MEASURES Myonuclei per fiber and cross-sectional area (CSA) of trapezius muscle fibers. RESULTS There were no significant differences between C (n = 5), RT (n = 15), RT-AS (n = 17), and PREV (n = 6) for myonuclei per fiber. Three of 5 returning participants (RP1-3) were biopsied twice. Before visit 1, RP1 ceased AAS usage 34 weeks before, RP2 and RP3 ceased AAS usage ≤2 weeks before, and all had 28 weeks between visits. Fiber CSA decreased for RP1 and RP2 between visits (7566 vs 6629 μm 2 ; 7854 vs 5677 μm 2 ) while myonuclei per fiber remained similar (3.5 vs 3.4; 2.5 vs 2.6). Respectively, these values increased for RP3 between visits (7167 vs 7889 μm 2 ; 2.6 vs 3.3). CONCLUSIONS This cohort of past AAS users did not have elevated myonuclei per fiber values, unlike previous research, but reported AAS usage was much lower. Training and AAS usage history also varied widely among participants. Comparable myonuclei per fiber numbers despite decrements in fiber CSA postexposure adheres with the muscle memory mechanism, but there is variation in usage relative to sampling date and low numbers of returning participants.
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Affiliation(s)
- Giscard Lima
- School of Sport and Health Sciences, University of Brighton, Eastbourne, United Kingdom
- Department of Movement, Human and Health Sciences, University of Rome "Foro Italico," Rome, Italy
| | | | - Guan Wang
- School of Sport and Health Sciences, University of Brighton, Eastbourne, United Kingdom
| | - Patrick Ho
- Murdoch Children's Research Institute, Department of Paediatrics, University of Melbourne, Australia
| | - Lyra Meehan
- Murdoch Children's Research Institute, Department of Paediatrics, University of Melbourne, Australia
| | - Kelly Roeszler
- Murdoch Children's Research Institute, Department of Paediatrics, University of Melbourne, Australia
| | - Jane Seto
- Murdoch Children's Research Institute, Department of Paediatrics, University of Melbourne, Australia
| | | | - Antonia Karanikolou
- School of Sport and Health Sciences, University of Brighton, Eastbourne, United Kingdom
| | - Gregor Eichhorn
- School of Sport and Health Sciences, University of Brighton, Eastbourne, United Kingdom
- Environmental Extremes Laboratory, University of Brighton, Eastbourne, United Kingdom
| | - Kumpei Tanisawa
- Faculty of Sport Sciences, Waseda University, Tokorozawa, Japan
| | | | - Blair Hamilton
- School of Sport and Health Sciences, University of Brighton, Eastbourne, United Kingdom
- School of Applied Sciences, University of Brighton, Brighton, United Kingdom
- Centre for Stress and Age-related Disease, University of Brighton, Brighton, United Kingdom
- The Gender Identity Clinic Tavistock and Portman NHS Foundation Trust, London, United Kingdom
| | - Paulette Y O Kumi
- Centre for Sports and Exercise Medicine, William Harvey Research Institute, Queen Mary University of London, United Kingdom
| | | | - Vasileios Skiadas
- University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom
| | - Richard Twycross-Lewis
- School of Engineering and Materials Science, Queen Mary University of London, London, United Kingdom
- University College of Football Business (UCFB Wembley Campus), Wembley, London, United Kingdom ; and
| | - Liam Kilduff
- Applied Sports, Technology, Exercise, and Medicine Research Centre (A-STEM), College of Engineering, Swansea University, Swansea, Wales
| | - Fergus M Guppy
- School of Sport and Health Sciences, University of Brighton, Eastbourne, United Kingdom
- School of Applied Sciences, University of Brighton, Brighton, United Kingdom
- Centre for Stress and Age-related Disease, University of Brighton, Brighton, United Kingdom
| | - Kathryn North
- Murdoch Children's Research Institute, Department of Paediatrics, University of Melbourne, Australia
| | - Yannis Pitsiladis
- School of Sport and Health Sciences, University of Brighton, Eastbourne, United Kingdom
- Department of Movement, Human and Health Sciences, University of Rome "Foro Italico," Rome, Italy
| | - Chiara Fossati
- Department of Movement, Human and Health Sciences, University of Rome "Foro Italico," Rome, Italy
| | - Fabio Pigozzi
- Department of Movement, Human and Health Sciences, University of Rome "Foro Italico," Rome, Italy
| | - Paolo Borrione
- Department of Movement, Human and Health Sciences, University of Rome "Foro Italico," Rome, Italy
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31
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Mesquita PHC, Godwin JS, Ruple BA, Sexton CL, McIntosh MC, Mueller BJ, Osburn SC, Mobley CB, Libardi CA, Young KC, Gladden LB, Roberts MD, Kavazis AN. Resistance training diminishes mitochondrial adaptations to subsequent endurance training in healthy untrained men. J Physiol 2023; 601:3825-3846. [PMID: 37470322 PMCID: PMC11062412 DOI: 10.1113/jp284822] [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: 04/06/2023] [Accepted: 07/03/2023] [Indexed: 07/21/2023] Open
Abstract
We investigated the effects of performing a period of resistance training (RT) on the performance and molecular adaptations to a subsequent period of endurance training (ET). Twenty-five young adults were divided into an RT+ET group (n = 13), which underwent 7 weeks of RT followed by 7 weeks of ET, and an ET-only group (n = 12), which performed 7 weeks of ET. Body composition, endurance performance and muscle biopsies were collected before RT (T1, baseline for RT+ET), before ET (T2, after RT for RT+ET and baseline for ET) and after ET (T3). Immunohistochemistry was performed to determine fibre cross-sectional area (fCSA), myonuclear content, myonuclear domain size, satellite cell number and mitochondrial content. Western blots were used to quantify markers of mitochondrial remodelling. Citrate synthase activity and markers of ribosome content were also investigated. RT improved body composition and strength, increased vastus lateralis thickness, mixed and type II fCSA, myonuclear number, markers of ribosome content, and satellite cell content (P < 0.050). In response to ET, both groups similarly decreased body fat percentage (P < 0.0001) and improved endurance performance (e.g.V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_2}\max }}$ , and speed at which the onset of blood lactate accumulation occurred, P < 0.0001). Levels of mitochondrial complexes I-IV in the ET-only group increased 32-66%, while those in the RT+ET group increased 1-11% (time, P < 0.050). Additionally, mixed fibre relative mitochondrial content increased 15% in the ET-only group but decreased 13% in the RT+ET group (interaction, P = 0.043). In conclusion, RT performed prior to ET had no additional benefits to ET adaptations. Moreover, prior RT seemed to impair mitochondrial adaptations to ET. KEY POINTS: Resistance training is largely underappreciated as a method to improve endurance performance, despite reports showing it may improve mitochondrial function. Although several concurrent training studies are available, in this study we investigated the effects of performing a period of resistance training on the performance and molecular adaptations to subsequent endurance training. Prior resistance training did not improve endurance performance and impaired most mitochondrial adaptations to subsequent endurance training, but this effect may have been a result of detraining from resistance training.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Cleiton A. Libardi
- Department of Physical Education, Federal University of São Carlos, São Carlos, Brazil
| | - Kaelin C. Young
- Biomedical Sciences, Pacific Northwest University of Health Sciences, Yakima, WA, USA
| | | | - Michael D. Roberts
- School of Kinesiology, Auburn University, Auburn, AL, USA
- Edward Via College of Osteopathic Medicine, Auburn, AL, USA
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Dasgupta A, Gibbard DF, Schmitt RE, Arneson-Wissink PC, Ducharme AM, Bruinsma ES, Hawse JR, Jatoi A, Doles JD. A TGF-β/KLF10 signaling axis regulates atrophy-associated genes to induce muscle wasting in pancreatic cancer. Proc Natl Acad Sci U S A 2023; 120:e2215095120. [PMID: 37585460 PMCID: PMC10462925 DOI: 10.1073/pnas.2215095120] [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: 09/02/2022] [Accepted: 06/14/2023] [Indexed: 08/18/2023] Open
Abstract
Cancer cachexia, and its associated complications, represent a large and currently untreatable roadblock to effective cancer management. Many potential therapies have been proposed and tested-including appetite stimulants, targeted cytokine blockers, and nutritional supplementation-yet highly effective therapies are lacking. Innovative approaches to treating cancer cachexia are needed. Members of the Kruppel-like factor (KLF) family play wide-ranging and important roles in the development, maintenance, and metabolism of skeletal muscle. Within the KLF family, we identified KLF10 upregulation in a multitude of wasting contexts-including in pancreatic, lung, and colon cancer mouse models as well as in human patients. We subsequently interrogated loss-of-function of KLF10 as a potential strategy to mitigate cancer associated muscle wasting. In vivo studies leveraging orthotopic implantation of pancreas cancer cells into wild-type and KLF10 KO mice revealed significant preservation of lean mass and robust suppression of pro-atrophy muscle-specific ubiquitin ligases Trim63 and Fbxo32, as well as other factors implicated in atrophy, calcium signaling, and autophagy. Bioinformatics analyses identified Transforming growth factor beta (TGF-β), a known inducer of KLF10 and cachexia promoting factor, as a key upstream regulator of KLF10. We provide direct in vivo evidence that KLF10 KO mice are resistant to the atrophic effects of TGF-β. ChIP-based binding studies demonstrated direct binding to Trim63, a known wasting-associated atrogene. Taken together, we report a critical role for the TGF-β/KLF10 axis in the etiology of pancreatic cancer-associated muscle wasting and highlight the utility of targeting KLF10 as a strategy to prevent muscle wasting and limit cancer-associated cachexia.
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Affiliation(s)
- Aneesha Dasgupta
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN55905
- Department of Anatomy, Cell Biology, and Physiology, Indiana University School of Medicine, Indianapolis, IN46202
- Indiana Center for Musculoskeletal Health, Indianapolis, IN46202
- Tumor Microenvironment & Metastasis Program, Indiana University Simon Comprehensive Cancer Center, Indianapolis, IN46202
| | - Daniel F. Gibbard
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN55905
| | - Rebecca E. Schmitt
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN55905
- Department of Anatomy, Cell Biology, and Physiology, Indiana University School of Medicine, Indianapolis, IN46202
- Indiana Center for Musculoskeletal Health, Indianapolis, IN46202
- Tumor Microenvironment & Metastasis Program, Indiana University Simon Comprehensive Cancer Center, Indianapolis, IN46202
| | - Paige C. Arneson-Wissink
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN55905
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN55905
| | | | | | - John R. Hawse
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN55905
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN55905
| | - Aminah Jatoi
- Department of Oncology, Mayo Clinic, Rochester, MN55905
| | - Jason D. Doles
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN55905
- Department of Anatomy, Cell Biology, and Physiology, Indiana University School of Medicine, Indianapolis, IN46202
- Indiana Center for Musculoskeletal Health, Indianapolis, IN46202
- Tumor Microenvironment & Metastasis Program, Indiana University Simon Comprehensive Cancer Center, Indianapolis, IN46202
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN55905
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Miller MJ, Marcotte GR, Basisty N, Wehrfritz C, Ryan ZC, Strub MD, McKeen AT, Stern JI, Nath KA, Rasmussen BB, Judge AR, Schilling B, Ebert SM, Adams CM. The transcription regulator ATF4 is a mediator of skeletal muscle aging. GeroScience 2023; 45:2525-2543. [PMID: 37014538 PMCID: PMC10071239 DOI: 10.1007/s11357-023-00772-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 03/10/2023] [Indexed: 04/05/2023] Open
Abstract
Aging slowly erodes skeletal muscle strength and mass, eventually leading to profound functional deficits and muscle atrophy. The molecular mechanisms of skeletal muscle aging are not well understood. To better understand mechanisms of muscle aging, we investigated the potential role of ATF4, a transcription regulatory protein that can rapidly promote skeletal muscle atrophy in young animals deprived of adequate nutrition or activity. To test the hypothesis that ATF4 may be involved in skeletal muscle aging, we studied fed and active muscle-specific ATF4 knockout mice (ATF4 mKO mice) at 6 months of age, when wild-type mice have achieved peak muscle mass and function, and at 22 months of age, when wild-type mice have begun to manifest age-related muscle atrophy and weakness. We found that 6-month-old ATF4 mKO mice develop normally and are phenotypically indistinguishable from 6-month-old littermate control mice. However, as ATF4 mKO mice become older, they exhibit significant protection from age-related declines in strength, muscle quality, exercise capacity, and muscle mass. Furthermore, ATF4 mKO muscles are protected from some of the transcriptional changes characteristic of normal muscle aging (repression of certain anabolic mRNAs and induction of certain senescence-associated mRNAs), and ATF4 mKO muscles exhibit altered turnover of several proteins with important roles in skeletal muscle structure and metabolism. Collectively, these data suggest ATF4 as an essential mediator of skeletal muscle aging and provide new insight into a degenerative process that impairs the health and quality of life of many older adults.
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Affiliation(s)
- Matthew J Miller
- Division of Endocrinology, Diabetes, Metabolism and Nutrition, Departments of Medicine and Biochemistry and Molecular Biology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
- University of Iowa, Iowa City, IA, USA
| | - George R Marcotte
- Division of Endocrinology, Diabetes, Metabolism and Nutrition, Departments of Medicine and Biochemistry and Molecular Biology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
- University of Iowa, Iowa City, IA, USA
| | - Nathan Basisty
- Buck Institute for Research on Aging, Novato, CA, USA
- National Institute on Aging, NIH, Baltimore, MD, USA
| | | | - Zachary C Ryan
- Division of Endocrinology, Diabetes, Metabolism and Nutrition, Departments of Medicine and Biochemistry and Molecular Biology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Matthew D Strub
- Division of Endocrinology, Diabetes, Metabolism and Nutrition, Departments of Medicine and Biochemistry and Molecular Biology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | | | - Jennifer I Stern
- Division of Endocrinology, Diabetes, Metabolism and Nutrition, Departments of Medicine and Biochemistry and Molecular Biology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Karl A Nath
- Division of Endocrinology, Diabetes, Metabolism and Nutrition, Departments of Medicine and Biochemistry and Molecular Biology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Blake B Rasmussen
- University of Texas Medical Branch, Galveston, TX, USA
- Emmyon, Inc., Rochester, MN, USA
| | - Andrew R Judge
- University of Florida, Gainesville, FL, USA
- Emmyon, Inc., Rochester, MN, USA
| | | | - Scott M Ebert
- Division of Endocrinology, Diabetes, Metabolism and Nutrition, Departments of Medicine and Biochemistry and Molecular Biology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA.
- Emmyon, Inc., Rochester, MN, USA.
| | - Christopher M Adams
- Division of Endocrinology, Diabetes, Metabolism and Nutrition, Departments of Medicine and Biochemistry and Molecular Biology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA.
- Emmyon, Inc., Rochester, MN, USA.
- Iowa City Veterans Affairs Medical Center, Iowa City, IA, USA.
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Schmitt RE, Dasgupta A, Arneson‐Wissink PC, Datta S, Ducharme AM, Doles JD. Muscle stem cells contribute to long-term tissue repletion following surgical sepsis. J Cachexia Sarcopenia Muscle 2023; 14:1424-1440. [PMID: 36883680 PMCID: PMC10235871 DOI: 10.1002/jcsm.13214] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 01/18/2023] [Accepted: 02/03/2023] [Indexed: 03/09/2023] Open
Abstract
BACKGROUND Over the past decade, advances in sepsis identification and management have resulted in decreased sepsis mortality. This increase in survivorship has highlighted a new clinical obstacle: chronic critical illness (CCI), for which there are no effective treatment options. Up to half of sepsis survivors suffer from CCI, which can include multi-organ dysfunction, chronic inflammation, muscle wasting, physical and mental disabilities, and enhanced frailty. These symptoms prevent survivors from returning to regular day-to-day activities and are directly associated with poor quality of life. METHODS Mice were subjected to cecal ligation and puncture (CLP) with daily chronic stress (DCS) as an in vivo model to study sepsis late-effects/sequelae on skeletal muscle components. Longitudinal monitoring was performed via magnetic resonance imaging, skeletal muscle and/or muscle stem cell (MuSCs) assays (e.g., post-necropsy wet muscle weights, minimum Feret diameter measurements, in vitro MuSC proliferation and differentiation, number of regenerating myofibres and numbers of Pax7-positive nuclei per myofibre), post-sepsis whole muscle metabolomics and MuSC isolation and high-content transcriptional profiling. RESULTS We report several findings supporting the hypothesis that MuSCs/muscle regeneration are critically involved in post-sepsis muscle recovery. First, we show that genetic ablation of muscle stem cells (MuSCs) impairs post-sepsis muscle recovery (maintenance of 5-8% average lean mass loss compared with controls). Second, we observe impaired MuSCs expansion capacity and morphological defects at 26 days post-sepsis compared with control MuSCs (P < 0.001). Third, when subjected to an experimental muscle injury, sepsis-recovered mice exhibited evidence of impaired muscle regeneration compared with non-septic mice receiving the same muscle injury (CLP/DCS injured mean minimum Feret is 92.1% of control injured, P < 0.01). Fourth, we performed a longitudinal RNA sequencing study on MuSCs isolated from post-sepsis mice and found clear transcriptional differences in all post-sepsis samples compared with controls. At Day 28, CLP/DCS mice satellite cells have multiple altered metabolic pathways, such as oxidative phosphorylation, mitochondrial dysfunction, sirtuin signalling and oestrogen receptor signalling, compared with controls (P < 0.001). CONCLUSIONS Our data show that MuSCs and muscle regeneration are required for effective post-sepsis muscle recovery and that sepsis triggers morphological, functional, and transcriptional changes in MuSCs. Moving forward, we strive to leverage a more complete understanding of post-sepsis MuSC/regenerative defects to identify and test novel therapies that promote muscle recovery and improve quality of life in sepsis survivors.
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Affiliation(s)
- Rebecca E. Schmitt
- Department of Biochemistry and Molecular BiologyMayo ClinicRochesterMNUSA
- Department of Anatomy, Cell Biology, and PhysiologyIndiana University School of MedicineIndianapolisINUSA
- Indiana Center for Musculoskeletal HealthIndianapolisINUSA
| | - Aneesha Dasgupta
- Department of Biochemistry and Molecular BiologyMayo ClinicRochesterMNUSA
- Department of Anatomy, Cell Biology, and PhysiologyIndiana University School of MedicineIndianapolisINUSA
- Indiana Center for Musculoskeletal HealthIndianapolisINUSA
| | | | | | | | - Jason D. Doles
- Department of Biochemistry and Molecular BiologyMayo ClinicRochesterMNUSA
- Department of Anatomy, Cell Biology, and PhysiologyIndiana University School of MedicineIndianapolisINUSA
- Indiana Center for Musculoskeletal HealthIndianapolisINUSA
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Martin RA, Keeler SP, Wu K, Shearon WJ, Patel D, Li J, Hoang M, Hoffmann CM, Hughes ME, Holtzman MJ. An alternative mechanism for skeletal muscle dysfunction in long-term post-viral lung disease. Am J Physiol Lung Cell Mol Physiol 2023; 324:L870-L878. [PMID: 37130808 PMCID: PMC10259859 DOI: 10.1152/ajplung.00338.2022] [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: 10/07/2022] [Revised: 04/10/2023] [Accepted: 05/02/2023] [Indexed: 05/04/2023] Open
Abstract
Chronic lung disease is often accompanied by disabling extrapulmonary symptoms, notably skeletal muscle dysfunction and atrophy. Moreover, the severity of respiratory symptoms correlates with decreased muscle mass and in turn lowered physical activity and survival rates. Previous models of muscle atrophy in chronic lung disease often modeled chronic obstructive pulmonary disease (COPD) and relied on cigarette smoke exposure and LPS stimulation, but these conditions independently affect skeletal muscle even without accompanying lung disease. Moreover, there is an emerging and pressing need to understand the extrapulmonary manifestations of long-term post-viral lung disease (PVLD) as found in COVID-19. Here, we examine the development of skeletal muscle dysfunction in the setting of chronic pulmonary disease caused by infection due to the natural pathogen Sendai virus using a mouse model of PVLD. We identify a significant decrease in myofiber size when PVLD is maximal at 49 days after infection. We find no change in the relative types of myofibers, but the greatest decrease in fiber size is localized to fast-twitch-type IIB myofibers based on myosin heavy chain immunostaining. Remarkably, all biomarkers of myocyte protein synthesis and degradation (total RNA, ribosomal abundance, and ubiquitin-proteasome expression) were stable throughout the acute infectious illness and chronic post-viral disease process. Together, the results demonstrate a distinct pattern of skeletal muscle dysfunction in a mouse model of long-term PVLD. The findings thereby provide new insights into prolonged limitations in exercise capacity in patients with chronic lung disease after viral infections and perhaps other types of lung injury.NEW & NOTEWORTHY Our study used a mouse model of post-viral lung disease to study the impact of chronic lung disease on skeletal muscle. The model reveals a decrease in myofiber size that is selective for specific types of myofibers and an alternative mechanism for muscle atrophy that might be independent of the usual markers of protein synthesis and degradation. The findings provide a basis for new therapeutic strategies to correct skeletal muscle dysfunction in chronic respiratory disease.
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Affiliation(s)
- Ryan A Martin
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States
| | - Shamus P Keeler
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States
| | - Kangyun Wu
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States
| | - William J Shearon
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States
| | - Devin Patel
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States
| | - Jiajia Li
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States
| | - My Hoang
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States
| | - Christy M Hoffmann
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States
| | - Michael E Hughes
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States
| | - Michael J Holtzman
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri, United States
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Orozco-Aguilar J, Tacchi F, Aguirre F, Valero-Breton M, Castro-Sepulveda M, Simon F, Cabello-Verrugio C. Ursodeoxycholic acid induces sarcopenia associated with decreased protein synthesis and autophagic flux. Biol Res 2023; 56:28. [PMID: 37237400 DOI: 10.1186/s40659-023-00431-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 04/13/2023] [Indexed: 05/28/2023] Open
Abstract
BACKGROUND Skeletal muscle generates force and movements and maintains posture. Under pathological conditions, muscle fibers suffer an imbalance in protein synthesis/degradation. This event causes muscle mass loss and decreased strength and muscle function, a syndrome known as sarcopenia. Recently, our laboratory described secondary sarcopenia in a chronic cholestatic liver disease (CCLD) mouse model. Interestingly, the administration of ursodeoxycholic acid (UDCA), a hydrophilic bile acid, is an effective therapy for cholestatic hepatic alterations. However, the effect of UDCA on skeletal muscle mass and functionality has never been evaluated, nor the possible involved mechanisms. METHODS We assessed the ability of UDCA to generate sarcopenia in C57BL6 mice and develop a sarcopenic-like phenotype in C2C12 myotubes and isolated muscle fibers. In mice, we measured muscle strength by a grip strength test, muscle mass by bioimpedance and mass for specific muscles, and physical function by a treadmill test. We also detected the fiber's diameter and content of sarcomeric proteins. In C2C12 myotubes and/or isolated muscle fibers, we determined the diameter and troponin I level to validate the cellular effect. Moreover, to evaluate possible mechanisms, we detected puromycin incorporation, p70S6K, and 4EBP1 to evaluate protein synthesis and ULK1, LC3 I, and II protein levels to determine autophagic flux. The mitophagosome-like structures were detected by transmission electron microscopy. RESULTS UDCA induced sarcopenia in healthy mice, evidenced by decreased strength, muscle mass, and physical function, with a decline in the fiber's diameter and the troponin I protein levels. In the C2C12 myotubes, we observed that UDCA caused a reduction in the diameter and content of MHC, troponin I, puromycin incorporation, and phosphorylated forms of p70S6K and 4EBP1. Further, we detected increased levels of phosphorylated ULK1, the LC3II/LC3I ratio, and the number of mitophagosome-like structures. These data suggest that UDCA induces a sarcopenic-like phenotype with decreased protein synthesis and autophagic flux. CONCLUSIONS Our results indicate that UDCA induces sarcopenia in mice and sarcopenic-like features in C2C12 myotubes and/or isolated muscle fibers concomitantly with decreased protein synthesis and alterations in autophagic flux.
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Affiliation(s)
- Josué Orozco-Aguilar
- Laboratory of Muscle Pathology, Fragility and Aging, Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile
- Millennium Institute On Immunology and Immunotherapy, Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile
- Facultad de Farmacia, Universidad de Costa Rica, San José, Costa Rica
| | - Franco Tacchi
- Laboratory of Muscle Pathology, Fragility and Aging, Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile
- Millennium Institute On Immunology and Immunotherapy, Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile
| | - Francisco Aguirre
- Laboratory of Muscle Pathology, Fragility and Aging, Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile
- Millennium Institute On Immunology and Immunotherapy, Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile
| | - Mayalen Valero-Breton
- Laboratory of Muscle Pathology, Fragility and Aging, Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile
- Millennium Institute On Immunology and Immunotherapy, Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile
| | - Mauricio Castro-Sepulveda
- Exercise Physiology and Metabolism Laboratory, School of Kinesiology, Faculty of Medicine, Finis Terrae University, Santiago, Chile
| | - Felipe Simon
- Millennium Institute On Immunology and Immunotherapy, Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile.
- Laboratory of Integrative Physiopathology, Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile.
- Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Universidad de Chile, Santiago, Chile.
| | - Claudio Cabello-Verrugio
- Laboratory of Muscle Pathology, Fragility and Aging, Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile.
- Millennium Institute On Immunology and Immunotherapy, Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile.
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Dayan J, Goldman N, Waiger D, Melkman-Zehavi T, Halevy O, Uni Z. A deep learning-based automated image analysis for histological evaluation of broiler pectoral muscle. Poult Sci 2023; 102:102792. [PMID: 37276700 PMCID: PMC10258492 DOI: 10.1016/j.psj.2023.102792] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 05/14/2023] [Accepted: 05/15/2023] [Indexed: 06/07/2023] Open
Abstract
Global market demand for chicken breast muscle with high yield and quality, together with the high incidence rate of breast muscle abnormalities in recent years highlights the need for tools that can provide a rapid and precise evaluation of breast muscle development and morphology. In this study, we used a novel deep learning-based automated image analysis workflow combining Fiji (ImageJ) with Cellpose and MorphoLibJ plugins to generate an automated diameter and cross-sectional area quantification for broiler breast muscle. We compared data of myofiber diameter from 14-day-old broiler chicks, generated either by manual analysis or by automated analysis. Comparison between manual and automated analysis methods exhibited a striking accuracy rate of up to 99.91%. Moreover, the automated analysis method was much faster. When the automated analysis method was implemented on 84 breast muscle cross-section images it characterized 59,128 myofibers within 4.2 h, while manual analysis of 27 breast muscle cross-section images enabled analysis of 17,333 myofibers in 54 h. The automated image analysis method was also more productive, producing data sets of both diameter and cross-sectional area at an 80-fold higher rate than the manual analysis (26,279 vs. 321 data sets per hour, respectively). In order to demonstrate the ability of this automated image analysis tool to detect differences in breast muscle histomorphology, we applied it on cross sections from chicks of control and in ovo feeding group, injected with a methionine source [2-hydroxy-4-(methylthio) butanoic calcium salt (HMTBa)], known to effect skeletal muscle histomorphology. Analysis was performed on 19,807 myofibers from the control group and 21,755 myofibers from the HMTBa group and was completed in less than 1 h. The clear advantages of this automated image analysis workflow characterized by high precision, high speed, and high productiveness demonstrate its potential to be implemented as a reproducible and readily adaptable research or diagnostic tool for chicken breast muscle development and morphology.
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Affiliation(s)
- Jonathan Dayan
- Department of Animal Science, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 7610001, Israel
| | - Noam Goldman
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 7610001, Israel
| | - Daniel Waiger
- Center for Scientific Imaging, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 7610001, Israel
| | - Tal Melkman-Zehavi
- Department of Animal Science, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 7610001, Israel
| | - Orna Halevy
- Department of Animal Science, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 7610001, Israel
| | - Zehava Uni
- Department of Animal Science, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 7610001, Israel.
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Madigan LA, Jaime D, Fallon JR. MuSK-BMP signaling in adult muscle stem cells maintains quiescence and regulates myofiber size. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.17.541238. [PMID: 37292636 PMCID: PMC10245747 DOI: 10.1101/2023.05.17.541238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A central question in the biology of adult stem cells is elucidating the signaling pathways regulating their dynamics and function in diverse physiological and age-related contexts. Adult muscle stem cells (Satellite Cells; SCs) are generally quiescent but can activate and contribute to muscle homeostasis and repair. Here we tested the role of the MuSK-BMP pathway in regulating adult SC quiescence and myofiber size. We attenuated MuSK-BMP signaling by deletion of the BMP-binding MuSK Ig3 domain ('ΔIg3-MuSK') and studied the fast TA and EDL muscles. In germ line mutants at 3 months of age SC and myonuclei numbers as well as myofiber size were comparable in ΔIg3-MuSK and WT animals. However, in 5-month-old ΔIg3-MuSK animals SC density was decreased while myofiber size, myonuclear number and grip strength were increased - indicating that SCs had activated and productively fused into the myofibers over this interval. Notably, myonuclear domain size was conserved. Following injury, the mutant muscle fully regenerated with restoration of myofiber size and SC pool to WT levels, indicating that ΔIg3-MuSK SCs maintain full stem cell function. Conditional expression of ΔIg3-MuSK in adult SCs showed that the MuSK-BMP pathway regulates quiescence and myofiber size in a cell autonomous fashion. Transcriptomic analysis revealed that SCs from uninjured ΔIg3-MuSK mice exhibit signatures of activation, including elevated Notch and epigenetic signaling. We conclude that the MuSK-BMP pathway regulates SC quiescence and myofiber size in a cell autonomous, age-dependent manner. Targeting MuSK-BMP signaling in muscle stem cells thus emerges a therapeutic strategy for promoting muscle growth and function in the settings of injury, disease, and aging.
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Neyroud D, Laitano O, Dasgupta A, Lopez C, Schmitt RE, Schneider JZ, Hammers DW, Sweeney HL, Walter GA, Doles J, Judge SM, Judge AR. Blocking muscle wasting via deletion of the muscle-specific E3 ligase MuRF1 impedes pancreatic tumor growth. Commun Biol 2023; 6:519. [PMID: 37179425 PMCID: PMC10183033 DOI: 10.1038/s42003-023-04902-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 05/02/2023] [Indexed: 05/15/2023] Open
Abstract
Cancer-induced muscle wasting reduces quality of life, complicates or precludes cancer treatments, and predicts early mortality. Herein, we investigate the requirement of the muscle-specific E3 ubiquitin ligase, MuRF1, for muscle wasting induced by pancreatic cancer. Murine pancreatic cancer (KPC) cells, or saline, were injected into the pancreas of WT and MuRF1-/- mice, and tissues analyzed throughout tumor progression. KPC tumors induces progressive wasting of skeletal muscle and systemic metabolic reprogramming in WT mice, but not MuRF1-/- mice. KPC tumors from MuRF1-/- mice also grow slower, and show an accumulation of metabolites normally depleted by rapidly growing tumors. Mechanistically, MuRF1 is necessary for the KPC-induced increases in cytoskeletal and muscle contractile protein ubiquitination, and the depression of proteins that support protein synthesis. Together, these data demonstrate that MuRF1 is required for KPC-induced skeletal muscle wasting, whose deletion reprograms the systemic and tumor metabolome and delays tumor growth.
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Affiliation(s)
- Daria Neyroud
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA
- Myology Institute, University of Florida, Gainesville, FL, USA
- Institute of Sports Sciences, University of Lausanne, Lausanne, Switzerland
| | - Orlando Laitano
- Myology Institute, University of Florida, Gainesville, FL, USA
- Department of Applied Physiology & Kinesiology, University of Florida, Gainesville, FL, USA
| | - Aneesha Dasgupta
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - Christopher Lopez
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA
- Myology Institute, University of Florida, Gainesville, FL, USA
| | - Rebecca E Schmitt
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - Jessica Z Schneider
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - David W Hammers
- Myology Institute, University of Florida, Gainesville, FL, USA
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL, USA
| | - H Lee Sweeney
- Myology Institute, University of Florida, Gainesville, FL, USA
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL, USA
| | - Glenn A Walter
- Myology Institute, University of Florida, Gainesville, FL, USA
- Department of Physiology and Aging, University of Florida, Gainesville, FL, USA
| | - Jason Doles
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - Sarah M Judge
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA
- Myology Institute, University of Florida, Gainesville, FL, USA
| | - Andrew R Judge
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA.
- Myology Institute, University of Florida, Gainesville, FL, USA.
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Dominov JA, Madigan LA, Whitt JP, Rademacher KL, Webster KM, Zhang H, Banno H, Tang S, Zhang Y, Wightman N, Shychuck EM, Page J, Weiss A, Kelly K, Kucukural A, Brodsky MH, Jaworski A, Fallon JR, Lipscombe D, Brown RH. Up-regulation of cholesterol synthesis pathways and limited neurodegeneration in a knock-in Sod1 mutant mouse model of ALS. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.05.539444. [PMID: 37205335 PMCID: PMC10187330 DOI: 10.1101/2023.05.05.539444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a severe neurodegenerative disorder affecting brain and spinal cord motor neurons. Mutations in the copper/zinc superoxide dismutase gene ( SOD1 ) are associated with ∼20% of inherited and 1-2% of sporadic ALS cases. Much has been learned from mice expressing transgenic copies of mutant SOD1, which typically involve high-level transgene expression, thereby differing from ALS patients expressing one mutant gene copy. To generate a model that more closely represents patient gene expression, we created a knock-in point mutation (G85R, a human ALS-causing mutation) in the endogenous mouse Sod1 gene, leading to mutant SOD1 G85R protein expression. Heterozygous Sod1 G85R mutant mice resemble wild type, whereas homozygous mutants have reduced body weight and lifespan, a mild neurodegenerative phenotype, and express very low mutant SOD1 protein levels with no detectable SOD1 activity. Homozygous mutants exhibit partial neuromuscular junction denervation at 3-4 months of age. Spinal cord motor neuron transcriptome analyses of homozygous Sod1 G85R mice revealed up-regulation of cholesterol synthesis pathway genes compared to wild type. Transcriptome and phenotypic features of these mice are similar to Sod1 knock-out mice, suggesting the Sod1 G85R phenotype is largely driven by loss of SOD1 function. By contrast, cholesterol synthesis genes are down-regulated in severely affected human TgSOD1 G93A transgenic mice at 4 months. Our analyses implicate dysregulation of cholesterol or related lipid pathway genes in ALS pathogenesis. The Sod1 G85R knock-in mouse is a useful ALS model to examine the importance of SOD1 activity in control of cholesterol homeostasis and motor neuron survival. SIGNIFICANCE STATEMENT Amyotrophic lateral sclerosis is a devastating disease involving the progressive loss of motor neurons and motor function for which there is currently no cure. Understanding biological mechanisms leading to motor neuron death is critical for developing new treatments. Using a new knock-in mutant mouse model carrying a Sod1 mutation that causes ALS in patients, and in the mouse, causes a limited neurodegenerative phenotype similar to Sod1 loss-of-function, we show that cholesterol synthesis pathway genes are up-regulated in mutant motor neurons, whereas the same genes are down-regulated in transgenic SOD1 mice with a severe phenotype. Our data implicate dysregulation of cholesterol or other related lipid genes in ALS pathogenesis and provide new insights that could contribute to strategies for disease intervention.
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Reece TM, Godwin JS, Strube MJ, Ciccone AB, Stout KW, Pearson JR, Vopat BG, Gallagher PM, Roberts MD, Herda TJ. Myofiber hypertrophy adaptations following 6 weeks of low-load resistance training with blood flow restriction in untrained males and females. J Appl Physiol (1985) 2023; 134:1240-1255. [PMID: 37022967 PMCID: PMC10190928 DOI: 10.1152/japplphysiol.00704.2022] [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: 11/20/2022] [Revised: 03/30/2023] [Accepted: 03/31/2023] [Indexed: 04/07/2023] Open
Abstract
The effects of low-load resistance training with blood flow restriction (BFR) on hypertrophy of type I/II myofibers remains unclear, especially in females. The purpose of the present study is to examine changes in type I/II myofiber cross-sectional area (fCSA) and muscle CSA (mCSA) of the vastus lateralis (VL) from before (Pre) to after (Post) 6 wk of high-load resistance training (HL; n = 15, 8 females) and low-load resistance training with BFR (n = 16, 8 females). Mixed-effects models were used to analyze fCSA with group (HL, BFR), sex (M, F), fiber type (I, II), and time (Pre, Post) included as factors. mCSA increased from pre- to posttraining (P < 0.001, d = 0.91) and was greater in males compared with females (P < 0.001, d = 2.26). Type II fCSA increased pre- to post-HL (P < 0.05, d = 0.46) and was greater in males compared with females (P < 0.05, d = 0.78). There were no significant increases in fCSA pre- to post-BFR for either fiber type or sex. Cohen's d, however, revealed moderate effect sizes in type I and II fCSA for males (d = 0.59 and 0.67), although this did not hold true for females (d = 0.29 and 0.34). Conversely, the increase in type II fCSA was greater for females than for males after HL. In conclusion, low-load resistance training with BFR may not promote myofiber hypertrophy to the level of HL resistance training, and similar responses were generally observed for males and females. In contrast, comparable effect sizes for mCSA and 1-repetition maximum (1RM) between groups suggest that BFR could play a role in a resistance training program.NEW & NOTEWORTHY This is the first study, to our knowledge, to examine myofiber hypertrophy from low-load resistance training with blood flow restriction (BFR) in females. Although this type of training did not result in myofiber hypertrophy, there were comparable increases in muscle cross-sectional area compared with high-load resistance training. These findings possibly highlight that males and females respond in a similar manner to high-load resistance training and low-load resistance training with BFR.
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Affiliation(s)
- Tanner M Reece
- Program in Physical Therapy, Washington University School of Medicine, St. Louis, Missouri, United States
| | - Joshua S Godwin
- School of Kinesiology, Auburn University, Auburn, Alabama, United States
| | - Michael J Strube
- Department of Psychological and Brain Sciences, Washington University, St. Louis, Missouri, United States
| | - Anthony B Ciccone
- Department of Exercise Science and Outdoor Recreation, Utah Valley University, Orem, Utah, United States
| | - Kevan W Stout
- Department of Health, Sport, and Exercise Sciences, University of Kansas, Lawrence, Kansas, United States
| | - Jeremy R Pearson
- Department of Health, Sport, and Exercise Sciences, University of Kansas, Lawrence, Kansas, United States
| | - Bryan G Vopat
- University of Kansas School of Medicine-Wichita, Wichita, Kansas, United States
| | - Philip M Gallagher
- Department of Health, Sport, and Exercise Sciences, University of Kansas, Lawrence, Kansas, United States
| | - Michael D Roberts
- School of Kinesiology, Auburn University, Auburn, Alabama, United States
| | - Trent J Herda
- Department of Health, Sport, and Exercise Sciences, University of Kansas, Lawrence, Kansas, United States
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Mesquita PHC, Godwin JS, Ruple BA, Sexton CL, McIntosh MC, Mueller BJ, Osburn SC, Mobley CB, Libardi CA, Young KC, Gladden LB, Roberts MD, Kavazis AN. Resistance Training Diminishes Mitochondrial Adaptations to Subsequent Endurance Training. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.06.535919. [PMID: 37066356 PMCID: PMC10104141 DOI: 10.1101/2023.04.06.535919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/18/2023]
Abstract
We investigated the effects of performing a period of resistance training (RT) on the performance and molecular adaptations to a subsequent period of endurance training (ET). Twenty-five young adults were divided into RT+ET (n=13), which underwent seven weeks of RT followed by seven weeks of ET, and ET-only (n=12), which performed seven weeks of ET. Body composition, endurance performance, and muscle biopsies were collected before RT (T1, baseline for RT+ET), before ET (T2, post RT for RT+ET and baseline for ET), and after ET (T3). Immunohistochemistry was performed to determine fiber cross-sectional area (fCSA), myonuclear content, myonuclear domain size, satellite cell number, and mitochondrial content. Western blots were used to quantify markers of mitochondrial remodeling. Citrate synthase activity and markers of ribosome content were also investigated. Resistance training improved body composition and strength, increased vastus lateralis thickness, mixed and type II fCSA, myonuclear number, markers of ribosome content, and satellite cell content (p<0.050). In response to ET, both groups similarly decreased body fat percentage and improved endurance performance (e.g., VO 2 max, and speed at which the onset of blood lactate accumulation occurred during the VO 2 max test). Levels of mitochondrial complexes I-IV in the ET-only group increased 32-66%, while the RT+ET group increased 1-11%. Additionally, mixed fiber relative mitochondrial content increased 15% in the ET-only group but decreased 13% in the RT+ET group. In conclusion, RT performed prior to ET had no additional benefits to ET adaptations. Moreover, prior RT seemed to impair mitochondrial adaptations to ET. KEY POINTS SUMMARY Resistance training is largely underappreciated as a method to improve endurance performance, despite reports showing it may improve mitochondrial function.Although several concurrent training studies are available, in this study we investigated the effects of performing a period resistance training on the performance and molecular adaptations to subsequent endurance training.Prior resistance training did not improve endurance performance and impaired most mitochondrial adaptations to subsequent endurance training, but that seemed to be a result of detraining from resistance training.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Cleiton A. Libardi
- Department of Physical Education, Federal University of São Carlos, São Carlos, Brazil
| | - Kaelin C. Young
- Biomedical Sciences, Pacific Northwest University of Health Sciences, Yakima, WA, USA
| | | | - Michael D. Roberts
- School of Kinesiology, Auburn University, Auburn, AL, USA
- Edward Via College of Osteopathic Medicine, Auburn, AL, USA
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Wang K, Smith SH, Iijima H, Hettinger ZR, Mallepally A, Shroff SG, Ambrosio F. Bioengineered 3D Skeletal Muscle Model Reveals Complement 4b as a Cell-Autonomous Mechanism of Impaired Regeneration with Aging. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2207443. [PMID: 36650030 DOI: 10.1002/adma.202207443] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 12/11/2022] [Indexed: 05/17/2023]
Abstract
A mechanistic understanding of cell-autonomous skeletal muscle changes after injury can lead to novel interventions to improve functional recovery in an aged population. However, major knowledge gaps persist owing to limitations of traditional biological aging models. 2D cell culture represents an artificial environment, while aging mammalian models are contaminated by influences from non-muscle cells and other organs. Here, a 3D muscle aging system is created to overcome the limitations of these traditional platforms. It is shown that old muscle constructs (OMC) manifest a sarcopenic phenotype, as evidenced by hypotrophic myotubes, reduced contractile function, and decreased regenerative capacity compared to young muscle constructs. OMC also phenocopy the regenerative responses of aged muscle to two interventions, pharmacological and biological. Interrogation of muscle cell-specific mechanisms that contribute to impaired regeneration over time further reveals that an aging-induced increase of complement component 4b (C4b) delays muscle progenitor cell amplification and impairs functional recovery. However, administration of complement factor I, a C4b inactivator, improves muscle regeneration in vitro and in vivo, indicating that C4b inhibition may be a novel approach to enhance aged muscle repair. Collectively, the model herein exhibits capabilities to study cell-autonomous changes in skeletal muscle during aging, regeneration, and intervention.
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Affiliation(s)
- Kai Wang
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, 15213, USA
- Discovery Center for Musculoskeletal Recovery, Schoen Adams Research Institute at Spaulding, Charlestown, MA, 02129, USA
- Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, MA, 02115, USA
| | - Stephen H Smith
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Hirotaka Iijima
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Zachary R Hettinger
- Discovery Center for Musculoskeletal Recovery, Schoen Adams Research Institute at Spaulding, Charlestown, MA, 02129, USA
- Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, MA, 02115, USA
- Department of Medicine, Division of Geriatric Medicine, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Adarsh Mallepally
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Sanjeev G Shroff
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, 15213, USA
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Fabrisia Ambrosio
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, 15213, USA
- Discovery Center for Musculoskeletal Recovery, Schoen Adams Research Institute at Spaulding, Charlestown, MA, 02129, USA
- Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, MA, 02115, USA
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, 15213, USA
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, 15213, USA
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Ismaeel A, Van Pelt DW, Hettinger ZR, Fu X, Richards CI, Butterfield TA, Petrocelli JJ, Vechetti IJ, Confides AL, Drummond MJ, Dupont-Versteegden EE. Extracellular vesicle distribution and localization in skeletal muscle at rest and following disuse atrophy. Skelet Muscle 2023; 13:6. [PMID: 36895061 PMCID: PMC9999658 DOI: 10.1186/s13395-023-00315-1] [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: 12/04/2022] [Accepted: 02/24/2023] [Indexed: 03/11/2023] Open
Abstract
BACKGROUND Skeletal muscle (SkM) is a large, secretory organ that produces and releases myokines that can have autocrine, paracrine, and endocrine effects. Whether extracellular vesicles (EVs) also play a role in the SkM adaptive response and ability to communicate with other tissues is not well understood. The purpose of this study was to investigate EV biogenesis factors, marker expression, and localization across cell types in the skeletal muscle. We also aimed to investigate whether EV concentrations are altered by disuse atrophy. METHODS To identify the potential markers of SkM-derived EVs, EVs were isolated from rat serum using density gradient ultracentrifugation, followed by fluorescence correlation spectroscopy measurements or qPCR. Single-cell RNA sequencing (scRNA-seq) data from rat SkM were analyzed to assess the EV biogenesis factor expression, and cellular localization of tetraspanins was investigated by immunohistochemistry. Finally, to assess the effects of mechanical unloading on EV expression in vivo, EV concentrations were measured in the serum by nanoparticle tracking analysis in both a rat and human model of disuse. RESULTS In this study, we show that the widely used markers of SkM-derived EVs, α-sarcoglycan and miR-1, are undetectable in serum EVs. We also found that EV biogenesis factors, including the tetraspanins CD63, CD9, and CD81, are expressed by a variety of cell types in SkM. SkM sections showed very low detection of CD63, CD9, and CD81 in myofibers and instead accumulation within the interstitial space. Furthermore, although there were no differences in serum EV concentrations following hindlimb suspension in rats, serum EV concentrations were elevated in human subjects after bed rest. CONCLUSIONS Our findings provide insight into the distribution and localization of EVs in SkM and demonstrate the importance of methodological guidelines in SkM EV research.
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Affiliation(s)
- Ahmed Ismaeel
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - Douglas W Van Pelt
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Physical Therapy, University of Kentucky, Lexington, USA
| | - Zachary R Hettinger
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Physical Therapy, University of Kentucky, Lexington, USA
| | - Xu Fu
- Department of Chemistry, University of Kentucky, Lexington, KY, USA
| | | | - Timothy A Butterfield
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Athletic Training and Clinical Nutrition, University of Kentucky, Lexington, KY, USA
| | - Jonathan J Petrocelli
- Department of Physical Therapy & Athletic Training, University of Utah, Salt Lake City, UT, USA
| | - Ivan J Vechetti
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - Amy L Confides
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Physical Therapy, University of Kentucky, Lexington, USA
| | - Micah J Drummond
- Department of Physical Therapy & Athletic Training, University of Utah, Salt Lake City, UT, USA
| | - Esther E Dupont-Versteegden
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA.
- Department of Physiology, University of Kentucky, Lexington, KY, USA.
- Department of Physical Therapy, University of Kentucky, Lexington, USA.
- College of Health Sciences, University of Kentucky, 900 S. Limestone, CTW 210E, Lexington, KY, 40536-0200, USA.
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Jurberg AD, Gomes G, Seixas MR, Mermelstein C, Costa ML. Improving quantification of myotube width and nuclear/cytoplasmic ratio in myogenesis research. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2023; 230:107354. [PMID: 36682109 DOI: 10.1016/j.cmpb.2023.107354] [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: 09/07/2022] [Revised: 01/05/2023] [Accepted: 01/12/2023] [Indexed: 06/17/2023]
Abstract
BACKGROUND AND OBJECTIVE The culture of skeletal muscle cells is particularly relevant to basic biomedical research and translational medicine. The incubation of dissociated cells under controlled conditions has helped to dissect several molecular mechanisms associated with muscle cell differentiation, in addition to contributing for the evaluation of drug effects and prospective cell therapies for patients with degenerative muscle pathologies. The formation of mature multinucleated myotubes is a stepwise process involving well defined events of cell proliferation, commitment, migration, and fusion easily identified through optical microscopy methods including immunofluorescence and live cell imaging. The characterization of each step is usually based on muscle cell morphology and nuclei number, as well as the presence and intracellular location of specific cell markers. However, manual quantification of these parameters in large datasets of images is work-intensive and prone to researcher's subjectivity, mostly because of the extremely elongated cell shape of large myotubes and because myotubes are multinucleated. METHODS Here we provide two semi-automated ImageJ macros aimed to measure the width of myotubes and the nuclear/cytoplasmic localization of molecules in fluorescence images. The width measuring macro automatically determines the best angle, perpendicular to most cells, to draw a profile plot and identify and measure individual myotubes. The nuclear/cytoplasmic ratio macro compares the intensity values along lines, drawn by the user, over cytoplasm and nucleus. RESULTS We show that the macro measurements are more consistent than manual measurements by comparing with our own results and with the literature. CONCLUSIONS By relying on semi-automated muscle specific ImageJ macros, we seek to improve measurement accuracy and to alleviate the laborious routine of counting and measuring muscle cell features.
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Affiliation(s)
- Arnon Dias Jurberg
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro (UFRJ), RJ, Brazil; Instituto de Educação Médica (IDOMED), Campus Vista Carioca, Universidade Estácio de Sá (UNESA), RJ, Brazil
| | - Geyse Gomes
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro (UFRJ), RJ, Brazil
| | - Marianna Reis Seixas
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro (UFRJ), RJ, Brazil
| | - Claudia Mermelstein
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro (UFRJ), RJ, Brazil
| | - Manoel Luis Costa
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro (UFRJ), RJ, Brazil.
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Smith MA, Sexton CL, Smith KA, Osburn SC, Godwin JS, Beausejour JP, Ruple BA, Goodlett MD, Edison JL, Fruge AD, Robinson AT, Gladden LB, Young KC, Roberts MD. Molecular predictors of resistance training outcomes in young untrained female adults. J Appl Physiol (1985) 2023; 134:491-507. [PMID: 36633866 PMCID: PMC10190845 DOI: 10.1152/japplphysiol.00605.2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 01/10/2023] [Accepted: 01/10/2023] [Indexed: 01/13/2023] Open
Abstract
We sought to determine if the myofibrillar protein synthetic (MyoPS) response to a naïve resistance exercise (RE) bout, or chronic changes in satellite cell number and muscle ribosome content, were associated with hypertrophic outcomes in females or differed in those who classified as higher (HR) or lower (LR) responders to resistance training (RT). Thirty-four untrained college-aged females (23.4 ± 3.4 kg/m2) completed a 10-wk RT protocol (twice weekly). Body composition and leg imaging assessments, a right leg vastus lateralis biopsy, and strength testing occurred before and following the intervention. A composite score, which included changes in whole body lean/soft tissue mass (LSTM), vastus lateralis (VL) muscle cross-sectional area (mCSA), midthigh mCSA, and deadlift strength, was used to delineate upper and lower HR (n = 8) and LR (n = 8) quartiles. In all participants, training significantly (P < 0.05) increased LSTM, VL mCSA, midthigh mCSA, deadlift strength, mean muscle fiber cross-sectional area, satellite cell abundance, and myonuclear number. Increases in LSTM (P < 0.001), VL mCSA (P < 0.001), midthigh mCSA (P < 0.001), and deadlift strength (P = 0.001) were greater in HR vs. LR. The first-bout 24-hour MyoPS response was similar between HR and LR (P = 0.367). While no significant responder × time interaction existed for muscle total RNA concentrations (i.e., ribosome content) (P = 0.888), satellite cell abundance increased in HR (P = 0.026) but not LR (P = 0.628). Pretraining LSTM (P = 0.010), VL mCSA (P = 0.028), and midthigh mCSA (P < 0.001) were also greater in HR vs. LR. Female participants with an enhanced satellite cell response to RT, and more muscle mass before RT, exhibited favorable resistance training adaptations.NEW & NOTEWORTHY This study continues to delineate muscle biology differences between lower and higher responders to resistance training and is unique in that a female population was interrogated. As has been reported in prior studies, increases in satellite cell numbers are related to positive responses to resistance training. Satellite cell responsivity, rather than changes in muscle ribosome content per milligrams of tissue, may be a more important factor in delineating resistance-training responses in women.
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Affiliation(s)
- Morgan A Smith
- School of Kinesiology, Auburn University, Auburn, Alabama
| | - Casey L Sexton
- School of Kinesiology, Auburn University, Auburn, Alabama
| | - Kristen A Smith
- Department of Nutrition, Dietetics and Hospitality Management, Auburn University, Auburn, Alabama
| | | | | | | | | | - Michael D Goodlett
- Athletics Department, Auburn University, Auburn, Alabama
- Edward Via College of Osteopathic Medicine, Auburn, Alabama
| | - Joseph L Edison
- Athletics Department, Auburn University, Auburn, Alabama
- Edward Via College of Osteopathic Medicine, Auburn, Alabama
| | - Andrew D Fruge
- Department of Nutrition, Dietetics and Hospitality Management, Auburn University, Auburn, Alabama
- College of Nursing, Auburn University, Auburn, Alabama
| | | | | | - Kaelin C Young
- School of Kinesiology, Auburn University, Auburn, Alabama
- Edward Via College of Osteopathic Medicine, Auburn, Alabama
| | - Michael D Roberts
- School of Kinesiology, Auburn University, Auburn, Alabama
- Edward Via College of Osteopathic Medicine, Auburn, Alabama
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Kahn RE, Krater T, Larson JE, Encarnacion M, Karakostas T, Patel NM, Swaroop VT, Dayanidhi S. Resident muscle stem cell myogenic characteristics in postnatal muscle growth impairments in children with cerebral palsy. Am J Physiol Cell Physiol 2023; 324:C614-C631. [PMID: 36622072 PMCID: PMC9942895 DOI: 10.1152/ajpcell.00499.2022] [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: 11/09/2022] [Revised: 12/13/2022] [Accepted: 12/28/2022] [Indexed: 01/10/2023]
Abstract
Children with cerebral palsy (CP), a perinatal brain alteration, have impaired postnatal muscle growth, with some muscles developing contractures. Functionally, children are either able to walk or primarily use wheelchairs. Satellite cells are muscle stem cells (MuSCs) required for postnatal development and source of myonuclei. Only MuSC abundance has been previously reported in contractured muscles, with myogenic characteristics assessed only in vitro. We investigated whether MuSC myogenic, myonuclear, and myofiber characteristics in situ differ between contractured and noncontractured muscles, across functional levels, and compared with typically developing (TD) children with musculoskeletal injury. Open muscle biopsies were obtained from 36 children (30 CP, 6 TD) during surgery; contracture correction for adductors or gastrocnemius, or from vastus lateralis [bony surgery in CP, anterior cruciate ligament (ACL) repair in TD]. Muscle cross sections were immunohistochemically labeled for MuSC abundance, activation, proliferation, nuclei, myofiber borders, type-1 fibers, and collagen content in serial sections. Although MuSC abundance was greater in contractured muscles, primarily in type-1 fibers, their myogenic characteristics (activation, proliferation) were lower compared with noncontractured muscles. Overall, MuSC abundance, activation, and proliferation appear to be associated with collagen content. Myonuclear number was similar between all muscles, but only in contractured muscles were there associations between myonuclear number, MuSC abundance, and fiber cross-sectional area. Puzzlingly, MuSC characteristics were similar between ambulatory and nonambulatory children. Noncontractured muscles in children with CP had a lower MuSC abundance compared with TD-ACL injured children, but similar myogenic characteristics. Contractured muscles may have an intrinsic deficiency in developmental progression for postnatal MuSC pool establishment, needed for lifelong efficient growth and repair.
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Affiliation(s)
| | | | - Jill E Larson
- Shirley Ryan AbilityLab, Chicago, Illinois
- Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois
| | | | - Tasos Karakostas
- Shirley Ryan AbilityLab, Chicago, Illinois
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Neeraj M Patel
- Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois
| | - Vineeta T Swaroop
- Shirley Ryan AbilityLab, Chicago, Illinois
- Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois
| | - Sudarshan Dayanidhi
- Shirley Ryan AbilityLab, Chicago, Illinois
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois
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48
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Neyroud D, Laitano O, Daguspta A, Lopez C, Schmitt RE, Schneider JZ, Hammers DW, Sweeney HL, Walter GA, Doles J, Judge SM, Judge AR. Blocking muscle wasting via deletion of the muscle-specific E3 ubiquitin ligase MuRF1 impedes pancreatic tumor growth. RESEARCH SQUARE 2023:rs.3.rs-2524562. [PMID: 36798266 PMCID: PMC9934780 DOI: 10.21203/rs.3.rs-2524562/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Cancer-induced muscle wasting reduces quality of life, complicates or precludes cancer treatments, and predicts early mortality. Herein, we investigated the requirement of the muscle-specific E3 ubiquitin ligase, MuRF1, for muscle wasting induced by pancreatic cancer. Murine pancreatic cancer (KPC) cells, or saline, were injected into the pancreas of WT and MuRF1-/- mice, and tissues analyzed throughout tumor progression. KPC tumors induced progressive wasting of skeletal muscle and systemic metabolic reprogramming in WT mice, but not MuRF1-/- mice. KPC tumors from MuRF1-/- mice also grew slower, and showed an accumulation of metabolites normally depleted by rapidly growing tumors. Mechanistically, MuRF1 was necessary for the KPC-induced increases in cytoskeletal and muscle contractile protein ubiquitination, and the depression of proteins that support protein synthesis. Together, these data demonstrate that MuRF1 is required for KPC-induced skeletal muscle wasting, whose deletion reprograms the systemic and tumor metabolome and delays tumor growth.
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Affiliation(s)
- Daria Neyroud
- Department of Physical Therapy, University of Florida, Gainesville, USA
- Myology Institute, University of Florida, Gainesville, USA
- Institute of Sports Sciences, University of Lausanne, Lausanne, Switzerland
| | - Orlando Laitano
- Myology Institute, University of Florida, Gainesville, USA
- Department of Applied Physiology & Kinesiology, University of Florida, Gainesville, USA
| | - Aneesha Daguspta
- Department of Anatomy, Cell Biology and Physiology, Indiana university school of medicine, Indianapolis, Indiana
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota
| | - Christopher Lopez
- Department of Physical Therapy, University of Florida, Gainesville, USA
- Myology Institute, University of Florida, Gainesville, USA
| | - Rebecca E. Schmitt
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota
| | - Jessica Z. Schneider
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota
| | - David W. Hammers
- Myology Institute, University of Florida, Gainesville, USA
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, USA
| | - H. Lee Sweeney
- Myology Institute, University of Florida, Gainesville, USA
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, USA
| | - Glenn A Walter
- Myology Institute, University of Florida, Gainesville, USA
- Department of Physiology and Aging, University of Florida, Gainesville, USA
| | - Jason Doles
- Department of Anatomy, Cell Biology and Physiology, Indiana university school of medicine, Indianapolis, Indiana
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota
| | - Sarah M. Judge
- Department of Physical Therapy, University of Florida, Gainesville, USA
- Myology Institute, University of Florida, Gainesville, USA
| | - Andrew R Judge
- Department of Physical Therapy, University of Florida, Gainesville, USA
- Myology Institute, University of Florida, Gainesville, USA
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49
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Sexton CL, Godwin JS, McIntosh MC, Ruple BA, Osburn SC, Hollingsworth BR, Kontos NJ, Agostinelli PJ, Kavazis AN, Ziegenfuss TN, Lopez HL, Smith R, Young KC, Dwaraka VB, Frugé AD, Mobley CB, Sharples AP, Roberts MD. Skeletal Muscle DNA Methylation and mRNA Responses to a Bout of Higher versus Lower Load Resistance Exercise in Previously Trained Men. Cells 2023; 12:263. [PMID: 36672198 PMCID: PMC9856538 DOI: 10.3390/cells12020263] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 12/24/2022] [Accepted: 01/04/2023] [Indexed: 01/11/2023] Open
Abstract
We sought to determine the skeletal muscle genome-wide DNA methylation and mRNA responses to one bout of lower load (LL) versus higher load (HL) resistance exercise. Trained college-aged males (n = 11, 23 ± 4 years old, 4 ± 3 years self-reported training) performed LL or HL bouts to failure separated by one week. The HL bout (i.e., 80 Fail) consisted of four sets of back squats and four sets of leg extensions to failure using 80% of participants estimated one-repetition maximum (i.e., est. 1-RM). The LL bout (i.e., 30 Fail) implemented the same paradigm with 30% of est. 1-RM. Vastus lateralis muscle biopsies were collected before, 3 h, and 6 h after each bout. Muscle DNA and RNA were batch-isolated and analyzed using the 850k Illumina MethylationEPIC array and Clariom S mRNA microarray, respectively. Performed repetitions were significantly greater during the 30 Fail versus 80 Fail (p < 0.001), although total training volume (sets × reps × load) was not significantly different between bouts (p = 0.571). Regardless of bout, more CpG site methylation changes were observed at 3 h versus 6 h post exercise (239,951 versus 12,419, respectively; p < 0.01), and nuclear global ten-eleven translocation (TET) activity, but not global DNA methyltransferase activity, increased 3 h and 6 h following exercise regardless of bout. The percentage of genes significantly altered at the mRNA level that demonstrated opposite DNA methylation patterns was greater 3 h versus 6 h following exercise (~75% versus ~15%, respectively). Moreover, high percentages of genes that were up- or downregulated 6 h following exercise also demonstrated significantly inversed DNA methylation patterns across one or more CpG sites 3 h following exercise (65% and 82%, respectively). While 30 Fail decreased DNA methylation across various promoter regions versus 80 Fail, transcriptome-wide mRNA and bioinformatics indicated that gene expression signatures were largely similar between bouts. Bioinformatics overlay of DNA methylation and mRNA expression data indicated that genes related to "Focal adhesion," "MAPK signaling," and "PI3K-Akt signaling" were significantly affected at the 3 h and 6 h time points, and again this was regardless of bout. In conclusion, extensive molecular profiling suggests that post-exercise alterations in the skeletal muscle DNA methylome and mRNA transcriptome elicited by LL and HL training bouts to failure are largely similar, and this could be related to equal volumes performed between bouts.
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Affiliation(s)
- Casey L. Sexton
- School of Kinesiology, Auburn University, Auburn, AL 36849, USA
| | | | | | | | | | | | | | | | | | | | - Hector L. Lopez
- The Center for Applied Health Sciences, Canfield, OH 44406, USA
| | | | - Kaelin C. Young
- School of Kinesiology, Auburn University, Auburn, AL 36849, USA
- Edward Via College of Osteopathic Medicine, Auburn, AL 24060, USA
| | | | - Andrew D. Frugé
- College of Nursing, Auburn University, Auburn, AL 36849, USA
| | | | - Adam P. Sharples
- Institute for Physical Performance, Norwegian School of Sport Sciences, 0863 Oslo, Norway
| | - Michael D. Roberts
- School of Kinesiology, Auburn University, Auburn, AL 36849, USA
- Edward Via College of Osteopathic Medicine, Auburn, AL 24060, USA
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50
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Viggars MR, Owens DJ, Stewart C, Coirault C, Mackey AL, Jarvis JC. PCM1 labeling reveals myonuclear and nuclear dynamics in skeletal muscle across species. Am J Physiol Cell Physiol 2023; 324:C85-C97. [PMID: 36409178 DOI: 10.1152/ajpcell.00285.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Myonuclei transcriptionally regulate muscle fibers during homeostasis and adaptation to exercise. Their subcellular location and quantity are important when characterizing phenotypes of myopathies, the effect of treatments, and understanding the roles of satellite cells in muscle adaptation and muscle "memory." Difficulties arise in identifying myonuclei due to their proximity to the sarcolemma and closely residing interstitial cell neighbors. We aimed to determine to what extent (pericentriolar material-1) PCM1 is a specific marker of myonuclei in vitro and in vivo. Single isolated myofibers and cross sections from mice and humans were studied from several models including wild-type and Lamin A/C mutant mice after functional overload and damage and recovery in humans following forced eccentric contractions. Fibers were immunolabeled for PCM1, Pax7, and DNA. C2C12 myoblasts were also studied to investigate changes in PCM1 localization during myogenesis. PCM1 was detected at not only the nuclear envelope of myonuclei in mature myofibers and in newly formed myotubes but also centrosomes in proliferating myogenic precursors, which may or may not fuse to join the myofiber syncytium. PCM1 was also detected in nonmyogenic nuclei near the sarcolemma, especially in regenerating areas of the Lmna+/ΔK32 mouse and damaged human muscle. Although PCM1 is not completely specific to myonuclei, the impact that PCM1+ macrophages and interstitial cells have on myonuclei counts would be small in healthy muscle. PCM1 may prove useful as a marker of satellite cell dynamics due to the distinct change in localization during differentiation, revealing satellite cells in their quiescent (PCM1-), proliferating (PCM1+ centrosome), and prefusion states (PCM1+ nuclear envelope).
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Affiliation(s)
- Mark R Viggars
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom.,Department of Physiology and Aging, University of Florida, Gainesville, Florida.,Myology Institute, University of Florida, Gainesville, Florida
| | - Daniel J Owens
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom.,Sorbonne Université, INSERM, Myology Research Center, Paris, France
| | - Claire Stewart
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | | | - Abigail L Mackey
- Department of Orthopaedic Surgery, Institute of Sports Medicine Copenhagen, Copenhagen University Hospital - Bispebjerg and Frederiksberg, Copenhagen, Denmark.,Department of Biomedical Sciences, Faculty of Health and Medical Sciences, Center for Healthy Aging, Xlab, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Jonathan C Jarvis
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
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