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Lukasiewicz CJ, Tranah GJ, Evans DS, Coen PM, Barnes HN, Huo Z, Esser KA, Zhang X, Wolff C, Wu K, Lane NE, Kritchevsky SB, Newman AB, Cummings SR, Cawthon PM, Hepple RT. Higher expression of denervation-responsive genes is negatively associated with muscle volume and performance traits in the study of muscle, mobility, and aging (SOMMA). Aging Cell 2024; 23:e14115. [PMID: 38831622 PMCID: PMC11166368 DOI: 10.1111/acel.14115] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 01/23/2024] [Accepted: 02/02/2024] [Indexed: 06/05/2024] Open
Abstract
With aging skeletal muscle fibers undergo repeating cycles of denervation and reinnervation. In approximately the 8th decade of life reinnervation no longer keeps pace, resulting in the accumulation of persistently denervated muscle fibers that in turn cause an acceleration of muscle dysfunction. The significance of denervation in important clinical outcomes with aging is poorly studied. The Study of Muscle, Mobility, and Aging (SOMMA) is a large cohort study with the primary objective to assess how aging muscle biology impacts clinically important traits. Using transcriptomics data from vastus lateralis muscle biopsies in 575 participants we have selected 49 denervation-responsive genes to provide insights to the burden of denervation in SOMMA, to test the hypothesis that greater expression of denervation-responsive genes negatively associates with SOMMA participant traits that included time to walk 400 meters, fitness (VO2peak), maximal mitochondrial respiration, muscle mass and volume, and leg muscle strength and power. Consistent with our hypothesis, increased transcript levels of: a calciumdependent intercellular adhesion glycoprotein (CDH15), acetylcholine receptor subunits (CHRNA1, CHRND, CHRNE), a glycoprotein promoting reinnervation (NCAM1), a transcription factor regulating aspects of muscle organization (RUNX1), and a sodium channel (SCN5A) were each negatively associated with at least 3 of these traits. VO2peak and maximal respiration had the strongest negative associations with 15 and 19 denervation-responsive genes, respectively. In conclusion, the abundance of denervationresponsive gene transcripts is a significant determinant of muscle and mobility outcomes in aging humans, supporting the imperative to identify new treatment strategies to restore innervation in advanced age.
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Affiliation(s)
| | - Gregory J. Tranah
- California Pacific Medical Center Research InstituteSan FranciscoCaliforniaUSA
- Department of Epidemiology and BiostatisticsUniversity of CaliforniaSan FranciscoCaliforniaUSA
| | - Daniel S. Evans
- California Pacific Medical Center Research InstituteSan FranciscoCaliforniaUSA
- Department of Epidemiology and BiostatisticsUniversity of CaliforniaSan FranciscoCaliforniaUSA
| | - Paul M. Coen
- Translational Research Institute, Advent HealthOrlandoFloridaUSA
| | - Haley N. Barnes
- California Pacific Medical Center Research InstituteSan FranciscoCaliforniaUSA
| | - Zhiguang Huo
- Department of Physiology and AgingUniversity of Florida College of MedicineGainesvilleFloridaUSA
| | - Karyn A. Esser
- Department of Physiology and AgingUniversity of Florida College of MedicineGainesvilleFloridaUSA
| | - Xiping Zhang
- Department of Physiology and AgingUniversity of Florida College of MedicineGainesvilleFloridaUSA
| | - Christopher Wolff
- Department of Physiology and AgingUniversity of Florida College of MedicineGainesvilleFloridaUSA
| | - Kevin Wu
- Department of Physiology and AgingUniversity of Florida College of MedicineGainesvilleFloridaUSA
| | - Nancy E. Lane
- Department of Medicine, Division of RheumatologyUniversity of California Davis HealthSacramentoCaliforniaUSA
| | - Steven B. Kritchevsky
- Department of Internal MedicineWake Forest University School of MedicineWinston‐SalemNorth CarolinaUSA
| | - Anne B. Newman
- School of Public HealthUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Steven R. Cummings
- California Pacific Medical Center Research InstituteSan FranciscoCaliforniaUSA
- Department of Epidemiology and BiostatisticsUniversity of CaliforniaSan FranciscoCaliforniaUSA
| | - Peggy M. Cawthon
- California Pacific Medical Center Research InstituteSan FranciscoCaliforniaUSA
- Department of Epidemiology and BiostatisticsUniversity of CaliforniaSan FranciscoCaliforniaUSA
| | - Russell T. Hepple
- Department of Physical TherapyUniversity of FloridaGainesvilleFloridaUSA
- Department of Physiology and AgingUniversity of Florida College of MedicineGainesvilleFloridaUSA
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2
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Li A, Yi J, Li X, Dong L, Ostrow LW, Ma J, Zhou J. Distinct transcriptomic profile of satellite cells contributes to preservation of neuromuscular junctions in extraocular muscles of ALS mice. eLife 2024; 12:RP92644. [PMID: 38661532 PMCID: PMC11045223 DOI: 10.7554/elife.92644] [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: 04/26/2024] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neuromuscular disorder characterized by progressive weakness of almost all skeletal muscles, whereas extraocular muscles (EOMs) are comparatively spared. While hindlimb and diaphragm muscles of end-stage SOD1G93A (G93A) mice (a familial ALS mouse model) exhibit severe denervation and depletion of Pax7+satellite cells (SCs), we found that the pool of SCs and the integrity of neuromuscular junctions (NMJs) are maintained in EOMs. In cell sorting profiles, SCs derived from hindlimb and diaphragm muscles of G93A mice exhibit denervation-related activation, whereas SCs from EOMs of G93A mice display spontaneous (non-denervation-related) activation, similar to SCs from wild-type mice. Specifically, cultured EOM SCs contain more abundant transcripts of axon guidance molecules, including Cxcl12, along with more sustainable renewability than the diaphragm and hindlimb counterparts under differentiation pressure. In neuromuscular co-culture assays, AAV-delivery of Cxcl12 to G93A-hindlimb SC-derived myotubes enhances motor neuron axon extension and innervation, recapitulating the innervation capacity of EOM SC-derived myotubes. G93A mice fed with sodium butyrate (NaBu) supplementation exhibited less NMJ loss in hindlimb and diaphragm muscles. Additionally, SCs derived from G93A hindlimb and diaphragm muscles displayed elevated expression of Cxcl12 and improved renewability following NaBu treatment in vitro. Thus, the NaBu-induced transcriptomic changes resembling the patterns of EOM SCs may contribute to the beneficial effects observed in G93A mice. More broadly, the distinct transcriptomic profile of EOM SCs may offer novel therapeutic targets to slow progressive neuromuscular functional decay in ALS and provide possible 'response biomarkers' in pre-clinical and clinical studies.
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Affiliation(s)
- Ang Li
- Department of Kinesiology, College of Nursing and Health Innovation, The University of Texas at ArlingtonArlingtonUnited States
| | - Jianxun Yi
- Department of Kinesiology, College of Nursing and Health Innovation, The University of Texas at ArlingtonArlingtonUnited States
| | - Xuejun Li
- Department of Kinesiology, College of Nursing and Health Innovation, The University of Texas at ArlingtonArlingtonUnited States
| | - Li Dong
- Department of Kinesiology, College of Nursing and Health Innovation, The University of Texas at ArlingtonArlingtonUnited States
| | - Lyle W Ostrow
- Department of Neurology, Lewis Katz School of Medicine at Temple UniversityPhiladelphiaUnited States
| | - Jianjie Ma
- Department of Surgery, Division of Surgical Sciences, University of VirginiaCharlottesvilleUnited States
| | - Jingsong Zhou
- Department of Kinesiology, College of Nursing and Health Innovation, The University of Texas at ArlingtonArlingtonUnited States
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3
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Li A, Yi J, Li X, Dong L, Ostrow LW, Ma J, Zhou J. Distinct transcriptomic profile of satellite cells contributes to preservation of neuromuscular junctions in extraocular muscles of ALS mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.02.12.528218. [PMID: 36824725 PMCID: PMC9949002 DOI: 10.1101/2023.02.12.528218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neuromuscular disorder characterized by progressive weakness of almost all skeletal muscles, whereas extraocular muscles (EOMs) are comparatively spared. While hindlimb and diaphragm muscles of end-stage SOD1G93A (G93A) mice (a familial ALS mouse model) exhibit severe denervation and depletion of Pax7 + satellite cells (SCs), we found that the pool of SCs and the integrity of neuromuscular junctions (NMJs) are maintained in EOMs. In cell sorting profiles, SCs derived from hindlimb and diaphragm muscles of G93A mice exhibit denervation-related activation, whereas SCs from EOMs of G93A mice display spontaneous (non-denervation-related) activation, similar to SCs from wild-type mice. Specifically, cultured EOM SCs contain more abundant transcripts of axon guidance molecules, including Cxcl12 , along with more sustainable renewability than the diaphragm and hindlimb counterparts under differentiation pressure. In neuromuscular co-culture assays, AAV-delivery of Cxcl12 to G93A-hindlimb SC-derived myotubes enhances motor neuron axon extension and innervation, recapitulating the innervation capacity of EOM SC-derived myotubes. G93A mice fed with sodium butyrate (NaBu) supplementation exhibited less NMJ loss in hindlimb and diaphragm muscles. Additionally, SCs derived from G93A hindlimb and diaphragm muscles displayed elevated expression of Cxcl12 and improved renewability following NaBu treatment in vitro . Thus, the NaBu-induced transcriptomic changes resembling the patterns of EOM SCs may contribute to the beneficial effects observed in G93A mice. More broadly, the distinct transcriptomic profile of EOM SCs may offer novel therapeutic targets to slow progressive neuromuscular functional decay in ALS and provide possible "response biomarkers" in pre-clinical and clinical studies.
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Fard D, Barbiera A, Dobrowolny G, Tamagnone L, Scicchitano BM. Semaphorins: Missing Signals in Age-dependent Alteration of Neuromuscular Junctions and Skeletal Muscle Regeneration. Aging Dis 2024; 15:517-534. [PMID: 37728580 PMCID: PMC10917540 DOI: 10.14336/ad.2023.0801] [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: 05/03/2023] [Accepted: 08/01/2023] [Indexed: 09/21/2023] Open
Abstract
Skeletal muscle is characterized by a remarkable capacity to rearrange after physiological changes and efficiently regenerate. However, during aging, extensive injury, or pathological conditions, the complete regenerative program is severely affected, with a progressive loss of muscle mass and function, a condition known as sarcopenia. The compromised tissue repair program is attributable to the gradual depletion of stem cells and to altered regulatory signals. Defective muscle regeneration can severely affect re-innervation by motor axons, and neuromuscular junctions (NMJs) development, ultimately leading to skeletal muscle atrophy. Defects in NMJ formation and maintenance occur physiologically during aging and are responsible for the pathogenesis of several neuromuscular disorders. However, it is still largely unknown how neuromuscular connections are restored on regenerating fibers. It has been suggested that attractive and repelling signals used for axon guidance could be implicated in this process; in particular, guidance molecules called semaphorins play a key role. Semaphorins are a wide family of extracellular regulatory signals with a multifaceted role in cell-cell communication. Originally discovered as axon guidance factors, they have been implicated in cancer progression, embryonal organogenesis, skeletal muscle innervation, and other physiological and developmental functions in different tissues. In particular, in skeletal muscle, specific semaphorin molecules are involved in the restoration and remodeling of the nerve-muscle connections, thus emphasizing their plausible role to ensure the success of muscle regeneration. This review article aims to discuss the impact of aging on skeletal muscle regeneration and NMJs remodeling and will highlight the most recent insights about the role of semaphorins in this context.
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Affiliation(s)
- Damon Fard
- Sezione di Istologia ed Embriologia, Dipartimento di Scienze della Vita e Sanità Pubblica,Università Cattolica del Sacro Cuore, 00168 Roma, Italy.
| | - Alessandra Barbiera
- Sezione di Istologia ed Embriologia, Dipartimento di Scienze della Vita e Sanità Pubblica,Università Cattolica del Sacro Cuore, 00168 Roma, Italy.
| | - Gabriella Dobrowolny
- DAHFMO-Unità di Istologia ed Embriologia Medica, Sapienza Università di Roma, 00161 Roma, Italy.
| | - Luca Tamagnone
- Sezione di Istologia ed Embriologia, Dipartimento di Scienze della Vita e Sanità Pubblica,Università Cattolica del Sacro Cuore, 00168 Roma, Italy.
- Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Roma, Italy.
| | - Bianca Maria Scicchitano
- Sezione di Istologia ed Embriologia, Dipartimento di Scienze della Vita e Sanità Pubblica,Università Cattolica del Sacro Cuore, 00168 Roma, Italy.
- Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Roma, Italy.
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Marzetti E, Lozanoska-Ochser B, Calvani R, Landi F, Coelho-Júnior HJ, Picca A. Restoring Mitochondrial Function and Muscle Satellite Cell Signaling: Remedies against Age-Related Sarcopenia. Biomolecules 2024; 14:415. [PMID: 38672432 PMCID: PMC11048011 DOI: 10.3390/biom14040415] [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: 02/19/2024] [Revised: 03/24/2024] [Accepted: 03/27/2024] [Indexed: 04/28/2024] Open
Abstract
Sarcopenia has a complex pathophysiology that encompasses metabolic dysregulation and muscle ultrastructural changes. Among the drivers of intracellular and ultrastructural changes of muscle fibers in sarcopenia, mitochondria and their quality control pathways play relevant roles. Mononucleated muscle stem cells/satellite cells (MSCs) have been attributed a critical role in muscle repair after an injury. The involvement of mitochondria in supporting MSC-directed muscle repair is unclear. There is evidence that a reduction in mitochondrial biogenesis blunts muscle repair, thus indicating that the delivery of functional mitochondria to injured muscles can be harnessed to limit muscle fibrosis and enhance restoration of muscle function. Injection of autologous respiration-competent mitochondria from uninjured sites to damaged tissue has been shown to reduce infarct size and enhance cell survival in preclinical models of ischemia-reperfusion. Furthermore, the incorporation of donor mitochondria into MSCs enhances lung and cardiac tissue repair. This strategy has also been tested for regeneration purposes in traumatic muscle injuries. Indeed, the systemic delivery of mitochondria promotes muscle regeneration and restores muscle mass and function while reducing fibrosis during recovery after an injury. In this review, we discuss the contribution of altered MSC function to sarcopenia and illustrate the prospect of harnessing mitochondrial delivery and restoration of MSCs as a therapeutic strategy against age-related sarcopenia.
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Affiliation(s)
- Emanuele Marzetti
- Fondazione Policlinico Universitario “Agostino Gemelli” IRCCS, L.go A. Gemelli 8, 00168 Rome, Italy; (R.C.); (F.L.)
- Department of Geriatrics, Orthopedics and Rheumatology, Università Cattolica del Sacro Cuore, L.go F. Vito 1, 00168 Rome, Italy;
| | - Biliana Lozanoska-Ochser
- Department of Medicine and Surgery, LUM University, 70010 Casamassima, Italy;
- DAHFMO Unit of Histology and Medical Embryology, Sapienza Università di Roma, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Riccardo Calvani
- Fondazione Policlinico Universitario “Agostino Gemelli” IRCCS, L.go A. Gemelli 8, 00168 Rome, Italy; (R.C.); (F.L.)
- Department of Geriatrics, Orthopedics and Rheumatology, Università Cattolica del Sacro Cuore, L.go F. Vito 1, 00168 Rome, Italy;
| | - Francesco Landi
- Fondazione Policlinico Universitario “Agostino Gemelli” IRCCS, L.go A. Gemelli 8, 00168 Rome, Italy; (R.C.); (F.L.)
- Department of Geriatrics, Orthopedics and Rheumatology, Università Cattolica del Sacro Cuore, L.go F. Vito 1, 00168 Rome, Italy;
| | - Hélio José Coelho-Júnior
- Department of Geriatrics, Orthopedics and Rheumatology, Università Cattolica del Sacro Cuore, L.go F. Vito 1, 00168 Rome, Italy;
| | - Anna Picca
- Fondazione Policlinico Universitario “Agostino Gemelli” IRCCS, L.go A. Gemelli 8, 00168 Rome, Italy; (R.C.); (F.L.)
- Department of Medicine and Surgery, LUM University, 70010 Casamassima, Italy;
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Korb A, Tajbakhsh S, Comai GE. Functional specialisation and coordination of myonuclei. Biol Rev Camb Philos Soc 2024. [PMID: 38477382 DOI: 10.1111/brv.13063] [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: 04/10/2023] [Revised: 01/30/2024] [Accepted: 02/02/2024] [Indexed: 03/14/2024]
Abstract
Myofibres serve as the functional unit for locomotion, with the sarcomere as fundamental subunit. Running the entire length of this structure are hundreds of myonuclei, located at the periphery of the myofibre, juxtaposed to the plasma membrane. Myonuclear specialisation and clustering at the centre and ends of the fibre are known to be essential for muscle contraction, yet the molecular basis of this regionalisation has remained unclear. While the 'myonuclear domain hypothesis' helped explain how myonuclei can independently govern large cytoplasmic territories, novel technologies have provided granularity on the diverse transcriptional programs running simultaneously within the syncytia and added a new perspective on how myonuclei communicate. Building upon this, we explore the critical cellular and molecular sources of transcriptional and functional heterogeneity within myofibres, discussing the impact of intrinsic and extrinsic factors on myonuclear programs. This knowledge provides new insights for understanding muscle development, repair, and disease, but also opens avenues for the development of novel and precise therapeutic approaches.
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Affiliation(s)
- Amaury Korb
- Institut Pasteur, Université Paris Cité, CNRS UMR 3738, Stem Cells & Development Unit, 25 rue du Dr. Roux, Institut Pasteur, Paris, F-75015, France
| | - Shahragim Tajbakhsh
- Institut Pasteur, Université Paris Cité, CNRS UMR 3738, Stem Cells & Development Unit, 25 rue du Dr. Roux, Institut Pasteur, Paris, F-75015, France
| | - Glenda E Comai
- Institut Pasteur, Université Paris Cité, CNRS UMR 3738, Stem Cells & Development Unit, 25 rue du Dr. Roux, Institut Pasteur, Paris, F-75015, France
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7
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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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8
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Sieck GC, Hernandez-Vizcarrondo GA, Brown AD, Fogarty MJ. Sarcopenia of the longitudinal tongue muscles in rats. Respir Physiol Neurobiol 2024; 319:104180. [PMID: 37863156 PMCID: PMC10851598 DOI: 10.1016/j.resp.2023.104180] [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: 08/08/2023] [Revised: 09/29/2023] [Accepted: 10/14/2023] [Indexed: 10/22/2023]
Abstract
The tongue is a muscular hydrostat, with lingual movements occurring during breathing, chewing, swallowing, vocalization, vomiting, coughing and grooming/sexual activities. In the elderly, reduced lingual dysfunction and weakness contribute to increased risks of obstructive sleep apnea and aspiration pneumonia. In Fischer 344 (F344) rats, a validated model of aging, hypoglossal motor neuron death is apparent, although there is no information regarding tongue strength. The intrinsic tongue muscles, the superior and inferior longitudinal, transversalis and verticalis exist in an interdigitated state. Recently, we established a method to measure the specific force of individual intrinsic tongue muscle, accounting for the tissue bulk that is not in the direction of uniaxial force. In the longitudinal muscles of 6- (n = 10), 18- (n = 9) and 24-month-old (n = 12) female and male F344 rats, we assessed specific force, fatigability, fiber type dependent cross-sectional area (CSA) and overall CSA. Muscle force and fatigue was assessed ex vivo using platinum plate simulation electrodes. Tongue muscles were frozen in melting isopentane, and transverse sections cut at 10 µm. Muscle fiber type was classified based on immunoreactivity to myosin heavy chain (MyHC) isoform antibodies. In H&E stained muscle, CSA and uniaxial muscle contributions to total tongue bulk was assessed. We observed a robust ∼30% loss of longitudinal specific force, with reductions in overall longitudinal muscle fiber CSA and specific atrophy of type IIx/IIb fibers. It will be important to investigate the mechanistic underpinnings of hypoglossal motor neuron death and tongue muscle weakness to eventually provide therapies for age-associated lingual dysfunctions.
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Affiliation(s)
- Gary C Sieck
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA
| | | | - Alyssa D Brown
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA
| | - Matthew J Fogarty
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA.
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Nuccio A, Nogueira-Ferreira R, Moreira-Pais A, Attanzio A, Duarte JA, Luparello C, Ferreira R. The contribution of mitochondria to age-related skeletal muscle wasting: A sex-specific perspective. Life Sci 2024; 336:122324. [PMID: 38042281 DOI: 10.1016/j.lfs.2023.122324] [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: 09/09/2023] [Revised: 11/27/2023] [Accepted: 11/29/2023] [Indexed: 12/04/2023]
Abstract
As people age, their skeletal muscle (SkM) experiences a decline in mitochondrial functionality and density, which leads to decreased energy production and increased generation of reactive oxygen species. This cascade of events, in turn, might determine the loss of SkM mass, strength and quality. Even though the mitochondrial processes dysregulated by aging, such as oxidative phosphorylation, mitophagy, antioxidant defenses and mtDNA transcription, are the same in both sexes, mitochondria age differently in the SkM of men and women. Indeed, the onset and magnitude of the impairment of these processes seem to be influenced by sex-specific factors. Sexual hormones play a pivotal role in the regulation of SkM mass through both genomic and non-genomic mechanisms. However, the precise mechanisms by which these hormones regulate mitochondrial plasticity in SkM are not fully understood. Although the presence of estrogen receptors in mitochondria is recognized, it remains unclear whether androgen receptors affect mitochondrial function. This comprehensive review critically dissects the current knowledge on the interplay of sex in the aging of SkM, focusing on the role of sex hormones and the corresponding signaling pathways in shaping mitochondrial plasticity. Improved knowledge on the sex dimorphism of mitochondrial aging may lead to sex-tailored interventions that target mitochondrial health, which could be effective in slowing or preventing age-related muscle loss.
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Affiliation(s)
- Alessandro Nuccio
- LAQV/REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal; Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, 90128 Palermo, Italy.
| | - Rita Nogueira-Ferreira
- Cardiovascular R&D Center - UnIC@RISE, Department of Surgery and Physiology, Faculty of Medicine of the University of Porto, 4200-319 Porto, Portugal.
| | - Alexandra Moreira-Pais
- LAQV/REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal; Research Center in Physical Activity, Health and Leisure (CIAFEL), Faculty of Sports, University of Porto (FADEUP), Laboratory for Integrative and Translational Research in Population Health (ITR), 4200-450 Porto, Portugal; Centre for Research and Technology of Agro Environmental and Biological Sciences (CITAB), Inov4Agro, University of Trás-os-Montes and Alto Douro (UTAD), Quinta de Prados, 5000-801 Vila Real, Portugal.
| | - Alessandro Attanzio
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, 90128 Palermo, Italy.
| | - José Alberto Duarte
- Research Center in Physical Activity, Health and Leisure (CIAFEL), Faculty of Sports, University of Porto (FADEUP), Laboratory for Integrative and Translational Research in Population Health (ITR), 4200-450 Porto, Portugal; TOXRUN - Toxicology Research Unit, University Institute of Health Sciences, CESPU, CRL, 4585-116 Gandra, Portugal.
| | - Claudio Luparello
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, 90128 Palermo, Italy.
| | - Rita Ferreira
- LAQV/REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
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Tøien T, Nielsen JL, Berg OK, Brobakken MF, Nyberg SK, Espedal L, Malmo T, Frandsen U, Aagaard P, Wang E. The impact of life-long strength versus endurance training on muscle fiber morphology and phenotype composition in older men. J Appl Physiol (1985) 2023; 135:1360-1371. [PMID: 37881849 PMCID: PMC10979801 DOI: 10.1152/japplphysiol.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: 03/31/2023] [Revised: 10/11/2023] [Accepted: 10/25/2023] [Indexed: 10/27/2023] Open
Abstract
Aging is typically associated with decreased muscle strength and rate of force development (RFD), partly explained by motor unit remodeling due to denervation, and subsequent loss of fast-twitch type II myofibers. Exercise is commonly advocated to counteract this detrimental loss. However, it is unclear how life-long strength versus endurance training may differentially affect markers of denervation and reinnervation of skeletal myofibers and, in turn, affect the proportion and morphology of fast-twitch type II musculature. Thus, we compared fiber type distribution, fiber type grouping, and the prevalence of atrophic myofibers (≤1,494 µm2) in strength-trained (OS) versus endurance-trained (OE) master athletes and compared the results to recreationally active older adults (all >70 yr, OC) and young habitually active references (<30 yr, YC). Immunofluorescent stainings were performed on biopsy samples from vastus lateralis, along with leg press maximal strength and RFD measurements. OS demonstrated similar type II fiber distribution (OS: 52.0 ± 16.4%; YC: 51.1 ± 14.4%), fiber type grouping, maximal strength (OS: 170.0 ± 18.9 kg, YC: 151.0 ± 24.4 kg), and RFD (OS: 3,993 ± 894 N·s-1, YC: 3,470 ± 1,394 N·s-1) as young, and absence of atrophic myofibers (OS: 0.2 ± 0.7%; YC: 0.1 ± 0.4%). In contrast, OE and OC exhibited more atrophic fibers (OE: 1.2 ± 1.0%; OC: 1.1 ± 1.4%), more grouped fibers, and smaller proportion of type II fibers (OE: 39.3 ± 11.9%; OC: 35.0 ± 12.4%) than OS and YC (all P < 0.05). In conclusion, strength-trained master athletes were characterized by similar muscle morphology as young, which was not the case for recreationally active or endurance-trained old. These results indicate that strength training may preserve type II fibers with advancing age in older men, likely as a result of chronic use of high contractile force generation.NEW & NOTEWORTHY Aging is associated with loss of fast-twitch type II myofibers, motor unit remodeling, and grouping of myofibers. This study reveals, for the first time, that strength training preserves neural innervation of type II fibers, resulting in similar myofiber type distribution and grouping in life-long strength-trained master athletes as young moderately active adults. In contrast, life-long endurance-trained master athletes and recreationally active old adults demonstrated higher proportion of type I fibers accompanied by more marked grouping of type I myofibers, and more atrophic fibers compared with strength-trained master athletes and young individuals. Thus, strength training should be utilized as a training modality for preservation of fast-twitch musculature, maximal muscle strength, and rapid force capacity (RFD) with advancing age.
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Affiliation(s)
- Tiril Tøien
- Department of Health and Social Sciences, Molde University College, Molde, Norway
| | - Jakob Lindberg Nielsen
- Department of Sports Science and Clinical Biomechanics, Research Unit for Muscle Physiology and Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Ole Kristian Berg
- Department of Health and Social Sciences, Molde University College, Molde, Norway
| | - Mathias Forsberg Brobakken
- Department of Health and Social Sciences, Molde University College, Molde, Norway
- Department of Psychosis and Rehabilitation, Psychiatry Clinic, St. Olavs University Hospital, Trondheim, Norway
| | - Stian Kwak Nyberg
- Department of Anesthesiology and Intensive Care, Drammen Hospital, Vestre Viken Hospital Trust, Drammen, Norway
| | - Lars Espedal
- Department of Health and Social Sciences, Molde University College, Molde, Norway
| | - Thomas Malmo
- Norwegian Defence University College, Norwegian Armed Forces, Oslo, Norway
| | - Ulrik Frandsen
- Department of Sports Science and Clinical Biomechanics, Research Unit for Muscle Physiology and Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Per Aagaard
- Department of Sports Science and Clinical Biomechanics, Research Unit for Muscle Physiology and Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Eivind Wang
- Department of Health and Social Sciences, Molde University College, Molde, Norway
- Department of Psychosis and Rehabilitation, Psychiatry Clinic, St. Olavs University Hospital, Trondheim, Norway
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11
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Lukasiewicz CJ, Tranah GJ, Evans DS, Coen PM, Barnes HN, Huo Z, Esser KA, Lane NE, Kritchevsky SB, Newman AB, Cummings SR, Cawthon PM, Hepple RT. Higher Expression of Denervation-responsive Genes is Negatively Associated with Muscle Volume and Performance Traits in the Study of Muscle, Mobility and Aging (SOMMA). MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.11.04.23298090. [PMID: 37961531 PMCID: PMC10635277 DOI: 10.1101/2023.11.04.23298090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
With aging skeletal muscle fibers undergo repeating cycles of denervation and reinnervation. In approximately the 8 th decade of life reinnervation no longer keeps pace, resulting in the accumulation of persistently denervated muscle fibers that in turn cause an acceleration of muscle dysfunction. The significance of denervation in important clinical outcomes with aging is poorly studied. The Study of Muscle, Mobility and Aging (SOMMA) is a large cohort study with the primary objective to assess how aging muscle biology impacts clinically important traits. Using transcriptomics data from vastus lateralis muscle biopsies in 575 participants we have selected 49 denervation-responsive genes to provide insights to the burden of denervation in SOMMA, to test the hypothesis that greater expression of denervation-responsive genes negatively associates with SOMMA participant traits that included time to walk 400 meters, fitness (VO 2peak ), maximal mitochondrial respiration, muscle mass and volume, and leg muscle strength and power. Consistent with our hypothesis, increased transcript levels of: a calcium-dependent intercellular adhesion glycoprotein (CDH15), acetylcholine receptor subunits (Chrna1, Chrnd, Chrne), a glycoprotein promoting reinnervation (NCAM1), a transcription factor regulating aspects of muscle organization (RUNX1), and a sodium channel (SCN5A) were each negatively associated with at least 3 of these traits. VO 2peak and maximal respiration had the strongest negative associations with 15 and 19 denervation-responsive genes, respectively. In conclusion, the abundance of denervation-responsive gene transcripts is a significant determinant of muscle and mobility outcomes in aging humans, supporting the imperative to identify new treatment strategies to restore innervation in advanced age.
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12
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Bakooshli MA, Wang YX, Monti E, Su S, Kraft P, Nalbandian M, Alexandrova L, Wheeler JR, Vogel H, Blau HM. Regeneration of neuromuscular synapses after acute and chronic denervation by inhibiting the gerozyme 15-prostaglandin dehydrogenase. Sci Transl Med 2023; 15:eadg1485. [PMID: 37820010 PMCID: PMC10763629 DOI: 10.1126/scitranslmed.adg1485] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 09/22/2023] [Indexed: 10/13/2023]
Abstract
To date, there are no approved treatments for the diminished strength and paralysis that result from the loss of peripheral nerve function due to trauma, heritable neuromuscular diseases, or aging. Here, we showed that denervation resulting from transection of the sciatic nerve triggered a marked increase in the prostaglandin-degrading enzyme 15-hydroxyprostaglandin dehydrogenase (15-PGDH) in skeletal muscle in mice, providing evidence that injury drives early expression of this aging-associated enzyme or gerozyme. Treating mice with a small-molecule inhibitor of 15-PGDH promoted regeneration of motor axons and formation of neuromuscular synapses leading to an acceleration in recovery of force after an acute nerve crush injury. In aged mice with chronic denervation of muscles, treatment with the 15-PGDH inhibitor increased motor neuron viability and restored neuromuscular junctions and function. These presynaptic changes synergized with previously reported muscle tissue remodeling to result in a marked increase in the strength of aged muscles. We further found that 15-PGDH aggregates defined the target fibers that are histopathologic hallmarks of human neurogenic myopathies, suggesting that the gerozyme may be involved in their etiology. Our data suggest that inhibition of 15-PGDH may constitute a therapeutic strategy to physiologically boost prostaglandin E2, restore neuromuscular connectivity, and promote recovery of strength after acute or chronic denervation due to injury, disease, or aging.
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Affiliation(s)
- Mohsen A. Bakooshli
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Yu Xin Wang
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Center for Genetic Disorders and Aging, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Elena Monti
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Shiqi Su
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Peggy Kraft
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Minas Nalbandian
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Ludmila Alexandrova
- Vincent Coates Foundation Mass Spectrometry Laboratory, Stanford University, Stanford, CA 94305, USA
| | - Joshua R. Wheeler
- Department of Pathology, Stanford University, Stanford, CA 94305, USA
- Department of Neuropathology, Stanford University, Stanford, CA 94305, USA
| | - Hannes Vogel
- Department of Pathology, Stanford University, Stanford, CA 94305, USA
- Department of Neuropathology, Stanford University, Stanford, CA 94305, USA
| | - Helen M. Blau
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
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13
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Sherman DA, Rush J, Stock MS, D. Ingersoll C, E. Norte G. Neural drive and motor unit characteristics after anterior cruciate ligament reconstruction: implications for quadriceps weakness. PeerJ 2023; 11:e16261. [PMID: 37818333 PMCID: PMC10561646 DOI: 10.7717/peerj.16261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 09/18/2023] [Indexed: 10/12/2023] Open
Abstract
Purpose The purpose of this investigation was to compare the quality of neural drive and recruited quadriceps motor units' (MU) action potential amplitude (MUAPAMP) and discharge rate (mean firing rate (MFR)) relative to recruitment threshold (RT) between individuals with anterior cruciate ligament reconstruction (ACLR) and controls. Methods Fourteen individuals with ACLR and 13 matched controls performed trapezoidal knee extensor contractions at 30%, 50%, 70%, and 100% of their maximal voluntary isometric contraction (MVIC). Decomposition electromyography (dEMG) and torque were recorded concurrently. The Hoffmann reflex (H-reflex) and central activation ratio (CAR) were acquired bilaterally to detail the proportion of MU pool available and volitionally activated. We examined MUAPAMP-RT and MFR-RT relationships with linear regression and extracted the regression line slope, y-intercept, and RT range for each contraction. Linear mixed effect modelling used to analyze the effect of group and limb on regression line slope and RT range. Results Individuals with ACLR demonstrated lower MVIC torque in the involved limb compared to uninvolved limb. There were no differences in H-reflex or CAR between groups or limbs. The ACLR involved limb demonstrated smaller mass-normalized RT range and slower MU firing rates at high contraction intensities (70% and 100% MVIC) compared to uninvolved and control limbs. The ACLR involved limb also demonstrated larger MU action potentials in the VM compared to the contralateral limb. These differences were largely attenuated with relative RT normalization. Conclusions These results suggest that persistent strength deficits following ACLR may be attributable to a diminished quadriceps motor neuron pool and inability to upregulate the firing rate of recruited MUs.
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Affiliation(s)
- David A. Sherman
- Live4 Physical Therapy and Wellness, Acton, Massachusetts, United States of America
- Chobanian & Avedisian School of Medicine, Boston University, Boston, Massachusetts, United States of America
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, United States of America
| | - Justin Rush
- Division of Physical Therapy, School of Rehabilitation and Communication Sciences, College of Health Sciences and Professions, Ohio University, Athens, Ohio, United States of America
| | - Matt S. Stock
- Cognition, Neuroplasticity, & Sarcopenia (CNS) Lab, Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, United States of America
| | - Christopher D. Ingersoll
- College of Health Professions and Sciences, School of Kinesiology and Rehabilitation Sciences, University of Central Florida, Orlando, Florida, United States of America
| | - Grant E. Norte
- Cognition, Neuroplasticity, & Sarcopenia (CNS) Lab, Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, United States of America
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14
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Barsky ST, Monks DA. Androgen action on myogenesis throughout the lifespan; comparison with neurogenesis. Front Neuroendocrinol 2023; 71:101101. [PMID: 37669703 DOI: 10.1016/j.yfrne.2023.101101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 08/31/2023] [Accepted: 09/02/2023] [Indexed: 09/07/2023]
Abstract
Androgens' pleiotropic actions in promoting sex differences present not only a challenge to providing a comprehensive account of their function, but also an opportunity to gain insights by comparing androgenic actions across organ systems. Although often overlooked by neuroscientists, skeletal muscle is another androgen-responsive organ system which shares with the nervous system properties of electrochemical excitability, behavioral relevance, and remarkable capacity for adaptive plasticity. Here we review androgenic regulation of mitogenic plasticity in skeletal muscle with the goal of identifying areas of interest to those researching androgenic mechanisms mediating sexual differentiation of neurogenesis. We use an organizational-activational framework to relate broad areas of similarity and difference between androgen effects on mitogenesis in muscle and brain throughout the lifespan, from early organogenesis, through pubertal organization, adult activation, and aging. The focus of the review is androgenic regulation of muscle-specific stem cells (satellite cells), which share with neural stem cells essential functions in development, plasticity, and repair, albeit with distinct, muscle-specific features. Also considered are areas of paracrine and endocrine interaction between androgen action on muscle and nervous system, including mediation of neural plasticity of innervating and distal neural populations by muscle-produced trophic factors.
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Affiliation(s)
- Sabrina Tzivia Barsky
- Department of Cell & Systems Biology, Faculty of Arts & Science, University of Toronto, Toronto, Ontario, Canada.
| | - Douglas Ashley Monks
- Department of Cell & Systems Biology, Faculty of Arts & Science, University of Toronto, Toronto, Ontario, Canada; Department of Psychology, Faculty of Arts & Science, University of Toronto Mississauga, Mississauga, Ontario, Canada.
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15
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Liao X, Wang Y, Lai X, Wang S. The role of Rapsyn in neuromuscular junction and congenital myasthenic syndrome. BIOMOLECULES & BIOMEDICINE 2023; 23:772-784. [PMID: 36815443 PMCID: PMC10494853 DOI: 10.17305/bb.2022.8641] [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: 12/21/2022] [Revised: 02/02/2023] [Accepted: 02/17/2023] [Indexed: 02/23/2023]
Abstract
Rapsyn, an intracellular scaffolding protein associated with the postsynaptic membranes in the neuromuscular junction (NMJ), is critical for nicotinic acetylcholine receptor clustering and maintenance. Therefore, Rapsyn is essential to the NMJ formation and maintenance, and Rapsyn mutant is one of the reasons causing the pathogenies of congenital myasthenic syndrome (CMS). In addition, there is little research on Rapsyn in the central nervous system (CNS). In this review, the role of Rapsyn in the NMJ formation and the mutation of Rapsyn leading to CMS will be reviewed separately and sequentially. Finally, the potential function of Rapsyn is prospected.
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Affiliation(s)
- Xufeng Liao
- Institute of Life Science and School of Life Sciences, Nanchang University, Nanchang, China
| | - Yingxing Wang
- Institute of Life Science and School of Life Sciences, Nanchang University, Nanchang, China
| | - Xinsheng Lai
- Institute of Life Science and School of Life Sciences, Nanchang University, Nanchang, China
- School of Basic Medical Sciences, Nanchang University, Nanchang, China
| | - Shunqi Wang
- Institute of Life Science and School of Life Sciences, Nanchang University, Nanchang, China
- School of Basic Medical Sciences, Nanchang University, Nanchang, China
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16
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Olmos AA, Sterczala AJ, Parra ME, Dimmick HL, Miller JD, Deckert JA, Sontag SA, Gallagher PM, Fry AC, Herda TJ, Trevino MA. Sex-related differences in motor unit behavior are influenced by myosin heavy chain during high- but not moderate-intensity contractions. Acta Physiol (Oxf) 2023; 239:e14024. [PMID: 37551144 DOI: 10.1111/apha.14024] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 07/18/2023] [Accepted: 07/19/2023] [Indexed: 08/09/2023]
Abstract
AIMS Motor unit recruitment and firing rate patterns of the vastus lateralis (VL) have not been compared between sexes during moderate- and high-intensity contraction intensities. Additionally, the influence of fiber composition on potential sex-related differences remains unquantified. METHODS Eleven males and 11 females performed 40% and 70% maximal voluntary contractions (MVCs). Surface electromyographic (EMG) signals recorded from the VL were decomposed. Recruitment thresholds (RTs), MU action potential amplitudes (MUAPAMP ), initial firing rates (IFRs), mean firing rates (MFRs), and normalized EMG amplitude (N-EMGRMS ) at steady torque were analyzed. Y-intercepts and slopes were calculated for MUAPAMP , IFR, and MFR versus RT relationships. Type I myosin heavy chain isoform (MHC) was determined with muscle biopsies. RESULTS There were no sex-related differences in MU characteristics at 40% MVC. At 70% MVC, males exhibited greater slopes (p = 0.002) for the MUAPAMP , whereas females displayed greater slopes (p = 0.001-0.007) for the IFR and MFR versus RT relationships. N-EMGRMS at 70% MVC was greater for females (p < 0.001). Type I %MHC was greater for females (p = 0.006), and was correlated (p = 0.018-0.031) with the slopes for the MUAPAMP , IFR, and MFR versus RT relationships at 70% MVC (r = -0.599-0.585). CONCLUSION Both sexes exhibited an inverse relationship between MU firing rates and recruitment thresholds. However, the sex-related differences in MU recruitment and firing rate patterns and N-EMGRMS at 70% MVC were likely due to greater type I% MHC and smaller twitch forces of the higher threshold MUs for the females. Evidence is provided that muscle fiber composition may explain divergent MU behavior between sexes.
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Affiliation(s)
- Alex A Olmos
- Applied Neuromuscular Physiology Lab, Department of Kinesiology, Applied Health, and Recreation, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Adam J Sterczala
- Neuromuscular Research Laboratory, Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Mandy E Parra
- School of Exercise and Sport Science, University of Mary Hardin-Baylor, Belton, Texas, USA
| | - Hannah L Dimmick
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Jonathan D Miller
- Department of Chemical and Petroleum Engineering, University of Kansas, Lawrence, Kansas, USA
| | - Jake A Deckert
- Department of Human Physiology, Gonzaga University, Spokane, Washington, USA
| | - Stephanie A Sontag
- Applied Neuromuscular Physiology Lab, Department of Kinesiology, Applied Health, and Recreation, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Philip M Gallagher
- Applied Physiology Laboratory, Department of Health, Sport, and Exercise Sciences, University of Kansas, Lawrence, Kansas, USA
| | - Andrew C Fry
- Jayhawk Athletic Performance Laboratory - Wu Tsai Human Performance Alliance, University of Kansas, Lawrence, Kansas, USA
| | - Trent J Herda
- Neuromechanics Laboratory, Department of Health, Sport, and Exercise Sciences, University of Kansas, Lawrence, Kansas, USA
| | - Michael A Trevino
- Applied Neuromuscular Physiology Lab, Department of Kinesiology, Applied Health, and Recreation, Oklahoma State University, Stillwater, Oklahoma, USA
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17
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GrönholdtKlein M, Gorzi A, Wang L, Edström E, Rullman E, Altun M, Ulfhake B. Emergence and Progression of Behavioral Motor Deficits and Skeletal Muscle Atrophy across the Adult Lifespan of the Rat. BIOLOGY 2023; 12:1177. [PMID: 37759577 PMCID: PMC10526071 DOI: 10.3390/biology12091177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 08/14/2023] [Accepted: 08/21/2023] [Indexed: 09/29/2023]
Abstract
The facultative loss of muscle mass and function during aging (sarcopenia) poses a serious threat to our independence and health. When activities of daily living are impaired (clinical phase), it appears that the processes leading to sarcopenia have been ongoing in humans for decades (preclinical phase). Here, we examined the natural history of sarcopenia in male outbred rats to compare the occurrence of motor behavioral deficits with the degree of muscle wasting and to explore the muscle-associated processes of the preclinical and clinical phases, respectively. Selected metrics were validated in female rats. We used the soleus muscle because of its long duty cycles and its importance in postural control. Results show that gait and coordination remain intact through middle age (40-60% of median lifespan) when muscle mass is largely preserved relative to body weight. However, the muscle shows numerous signs of remodeling with a shift in myofiber-type composition toward type I. As fiber-type prevalence shifted, fiber-type clustering also increased. The number of hybrid fibers, myofibers with central nuclei, and fibers expressing embryonic myosin increased from being barely detectable to a significant number (5-10%) at late middle age. In parallel, TGFβ1, Smad3, FBXO32, and MuRF1 mRNAs increased. In early (25-month-old) and advanced (30-month-old) aging, gait and coordination deteriorate with the progressive loss of muscle mass. In late middle age and early aging due to type II atrophy (>50%) followed by type I atrophy (>50%), the number of myofibers did not correlate with this process. In advanced age, atrophy is accompanied by a decrease in SCs and βCatenin mRNA, whereas several previously upregulated transcripts were downregulated. The re-expression of embryonic myosin in myofibers and the upregulation of mRNAs encoding the γ-subunit of the nicotinic acetylcholine receptor, the neuronal cell adhesion molecule, and myogenin that begins in late middle age suggest that one mechanism driving sarcopenia is the disruption of neuromuscular connectivity. We conclude that sarcopenia in rats, as in humans, has a long preclinical phase in which muscle undergoes extensive remodeling to maintain muscle mass and function. At later time points, these adaptive mechanisms fail, and sarcopenia becomes clinically manifest.
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Affiliation(s)
- Max GrönholdtKlein
- Department of Neuroscience, Karolinska Institutet, 171 77 Stockholm, Sweden;
| | - Ali Gorzi
- Department of Sport Sciences, University of Zanjan, Zanjan 45371-38791, Iran;
| | - Lingzhan Wang
- Department of Human Anatomy, Histology and Embryology, Inner Mongolia Minzu University, Tongliao 028000, China;
| | - Erik Edström
- Department of Clinical Neuroscience, Karolinska Institutet, 171 77 Stockholm, Sweden;
| | - Eric Rullman
- Department of Laboratory Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden; (E.R.); (M.A.)
| | - Mikael Altun
- Department of Laboratory Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden; (E.R.); (M.A.)
| | - Brun Ulfhake
- Department of Laboratory Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden; (E.R.); (M.A.)
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18
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Xu Y, Zhao L, Dong J, Jiang J, Jin L. Pathogenic SCN5A Mutation and Thyrotoxicosis-Related Neurological Syndrome: Casual or Causal Relationship? Brain Sci 2023; 13:1049. [PMID: 37508981 PMCID: PMC10377684 DOI: 10.3390/brainsci13071049] [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: 05/08/2023] [Revised: 07/05/2023] [Accepted: 07/07/2023] [Indexed: 07/30/2023] Open
Abstract
BACKGROUND Various neurologic complications of hyperthyroidism are reported, and most of these complications are reversible with the amelioration of thyrotoxicosis. We report a previously undescribed concurrence of hyperthyroid-associated exercise-induced myalgia and stiffness, pyramidal tract dysfunction, and myoclonic movements that make an initial clinical diagnosis difficult. CASE PRESENTATION A 17-year-old male was hospitalized in the department of neurology, presenting with a 4-year history of severe exercise-induced myalgia and stiffness, weakness of lower limbs, and myoclonic movements. Laboratory investigations unexpectedly revealed hyperthyroidism. MRI of the brain and spine, electrophysiology, and whole exome sequencing were also performed. Antithyroid therapy led to marked improvement of neurologic symptoms, accompanied by a significant improvement of the time-dependent decline in compound muscle action potentials (CMAP) amplitudes after exercise and normalization of the prolonged QTc interval. Genetic analysis identified a rare variant in SCN5A. CONCLUSION This case report provides important insights into the relationship between hyperthyroidism and neurologic/cardiac complications, particularly in those with a genetic predisposition. SCN5A mutation possibly plays a role in the complex neurological syndrome associated with hyperthyroidism. Further studies are warranted to better understand the underlying mechanisms and potential therapeutic options for these complex conditions.
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Affiliation(s)
- Yangqi Xu
- Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai 200030, China
| | - Lin Zhao
- Department of Endocrinology, Zhongshan Hospital, Fudan University, Shanghai 200030, China
| | - Jihong Dong
- Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai 200030, China
| | - Jingjing Jiang
- Department of Endocrinology, Zhongshan Hospital, Fudan University, Shanghai 200030, China
| | - Lirong Jin
- Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai 200030, China
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19
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Chung T, Bopp T, Ward C, Notarangelo FM, Schwarcz R, Westbrook R, Xue Q, Walston J, Hoke A. Deletion of quinolinate phosphoribosyltransferase gene accelerates frailty phenotypes and neuromuscular decline with aging in a sex-specific pattern. Aging Cell 2023; 22:e13849. [PMID: 37078472 PMCID: PMC10352574 DOI: 10.1111/acel.13849] [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: 11/04/2022] [Revised: 03/28/2023] [Accepted: 03/30/2023] [Indexed: 04/21/2023] Open
Abstract
Decline in neuromuscular function with aging is known to be a major determinant of disability and all-cause mortality in late life. Despite the importance of the problem, the neurobiology of age-associated muscle weakness is poorly understood. In a previous report, we performed untargeted metabolomics on frail older adults and discovered prominent alteration in the kynurenine pathway, the major route of dietary tryptophan degradation that produces neurotoxic intermediate metabolites. We also showed that neurotoxic kynurenine pathway metabolites are correlated with increased frailty score. For the present study, we sought to further examine the neurobiology of these neurotoxic intermediates by utilizing a mouse model that has a deletion of the quinolinate phosphoribosyltransferase (QPRT) gene, a rate-limiting step of the kynurenine pathway. QPRT-/- mice have elevated neurotoxic quinolinic acid level in the nervous system throughout their lifespan. We found that QPRT-/- mice have accelerated declines in neuromuscular function in an age- and sex-specific manner compared to control strains. In addition, the QPRT-/- mice show premature signs of frailty and body composition changes that are typical for metabolic syndrome. Our findings suggest that the kynurenine pathway may play an important role in frailty and age-associated muscle weakness.
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Affiliation(s)
- Tae Chung
- Department of Physical Medicine and RehabilitationJohns Hopkins University School of MedicineBaltimoreMarylandUSA
- Department of NeurologyNeuromuscular DivisionJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Taylor Bopp
- Department of Physical Medicine and RehabilitationJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Chris Ward
- Department of OrthopedicsUniversity of Maryland School of MedicineBaltimoreMarylandUSA
| | - Francesca M. Notarangelo
- Maryland Psychiatric Research CenterDepartment of PsychiatryUniversity of Maryland School of MedicineBaltimoreMarylandUSA
| | - Robert Schwarcz
- Maryland Psychiatric Research CenterDepartment of PsychiatryUniversity of Maryland School of MedicineBaltimoreMarylandUSA
| | - Reyhan Westbrook
- Department of Geriatric Medicine and GerontologyJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Qian‐Li Xue
- Department of Geriatric Medicine and GerontologyJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Jeremy Walston
- Department of Geriatric Medicine and GerontologyJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Ahmet Hoke
- Department of NeurologyNeuromuscular DivisionJohns Hopkins University School of MedicineBaltimoreMarylandUSA
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20
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Fogarty MJ. Loss of larger hypoglossal motor neurons in aged Fischer 344 rats. Respir Physiol Neurobiol 2023:104092. [PMID: 37331418 DOI: 10.1016/j.resp.2023.104092] [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: 05/05/2023] [Revised: 06/06/2023] [Accepted: 06/15/2023] [Indexed: 06/20/2023]
Abstract
The intrinsic (longitudinal, transversalis and verticalis) and extrinsic (genioglossus, styloglossus, hyoglossus and geniohyoid) tongue muscles are innervated by hypoglossal motor neurons (MNs). Tongue muscle activations occur during many behaviors: maintaining upper airway patency, chewing, swallowing, vocalization, vomiting, coughing, sneezing and grooming/sexual activities. In the tongues of the elderly, reduced oral motor function and strength contribute to increased risk of obstructive sleep apnoea. Tongue muscle atrophy and weakness is also described in rats, yet hypoglossal MN numbers are unknown. In young (6-months, n=10) and old (24-months, n=8) female and male Fischer 344 (F344) rats, stereological assessment of hypoglossal MN numbers and surface areas were performed on 16µm Nissl-stained brainstem cryosections. We observed a robust loss of ~15% of hypoglossal MNs and a modest ~8% reduction in their surface areas with age. In the larger size tertile of hypoglossal MNs, age-associated loss of hypoglossal MNs approached ~30% These findings uncover a potential neurogenic locus of pathology for age-associated tongue dysfunctions.
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Affiliation(s)
- Matthew J Fogarty
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN 55905.
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21
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Gatti M, Dittlau KS, Beretti F, Yedigaryan L, Zavatti M, Cortelli P, Palumbo C, Bertucci E, Van Den Bosch L, Sampaolesi M, Maraldi T. Human Neuromuscular Junction on a Chip: Impact of Amniotic Fluid Stem Cell Extracellular Vesicles on Muscle Atrophy and NMJ Integrity. Int J Mol Sci 2023; 24:ijms24054944. [PMID: 36902375 PMCID: PMC10003237 DOI: 10.3390/ijms24054944] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 03/01/2023] [Accepted: 03/02/2023] [Indexed: 03/08/2023] Open
Abstract
Neuromuscular junctions (NMJs) are specialized synapses, crucial for the communication between spinal motor neurons (MNs) and skeletal muscle. NMJs become vulnerable in degenerative diseases, such as muscle atrophy, where the crosstalk between the different cell populations fails, and the regenerative ability of the entire tissue is hampered. How skeletal muscle sends retrograde signals to MNs through NMJs represents an intriguing field of research, and the role of oxidative stress and its sources remain poorly understood. Recent works demonstrate the myofiber regeneration potential of stem cells, including amniotic fluid stem cells (AFSC), and secreted extracellular vesicles (EVs) as cell-free therapy. To study NMJ perturbations during muscle atrophy, we generated an MN/myotube co-culture system through XonaTM microfluidic devices, and muscle atrophy was induced in vitro by Dexamethasone (Dexa). After atrophy induction, we treated muscle and MN compartments with AFSC-derived EVs (AFSC-EVs) to investigate their regenerative and anti-oxidative potential in counteracting NMJ alterations. We found that the presence of EVs reduced morphological and functional in vitro defects induced by Dexa. Interestingly, oxidative stress, occurring in atrophic myotubes and thus involving neurites as well, was prevented by EV treatment. Here, we provided and validated a fluidically isolated system represented by microfluidic devices for studying human MN and myotube interactions in healthy and Dexa-induced atrophic conditions-allowing the isolation of subcellular compartments for region-specific analyses-and demonstrated the efficacy of AFSC-EVs in counteracting NMJ perturbations.
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Affiliation(s)
- Martina Gatti
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy
| | - Katarina Stoklund Dittlau
- Department of Neurosciences, Experimental Neurology and Leuven Brain Institute, KU Leuven—University of Leuven, 3000 Leuven, Belgium
- VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, 3000 Leuven, Belgium
| | - Francesca Beretti
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy
- Correspondence:
| | - Laura Yedigaryan
- Department of Development and Regeneration, Stem Cell and Developmental Biology, KU Leuven—University of Leuven, 3000 Leuven, Belgium
| | - Manuela Zavatti
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy
| | - Pietro Cortelli
- Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, 40127 Bologna, Italy
| | - Carla Palumbo
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy
| | - Emma Bertucci
- Department of Medical and Surgical Sciences for Mothers, Children and Adults, Azienda Ospedaliero Universitaria Policlinico, University of Modena and Reggio Emilia, 41124 Modena, Italy
| | - Ludo Van Den Bosch
- Department of Neurosciences, Experimental Neurology and Leuven Brain Institute, KU Leuven—University of Leuven, 3000 Leuven, Belgium
- VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, 3000 Leuven, Belgium
| | - Maurilio Sampaolesi
- Department of Development and Regeneration, Stem Cell and Developmental Biology, KU Leuven—University of Leuven, 3000 Leuven, Belgium
- Histology and Medical Embryology Unit, Department of Anatomy, Histology, Forensic Medicine and Orthopedics, Sapienza University of Rome, 00185 Rome, Italy
| | - Tullia Maraldi
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy
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22
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Arpke RW, Moritz TC, Hahn KL, Stark DA, Villalón E, Lorson CL, Cornelison DDW. Normal muscle fiber type distribution is recapitulated in aged ephrin-A3 -/- mice that previously lacked most slow myofibers. Am J Physiol Cell Physiol 2023; 324:C718-C727. [PMID: 36717102 PMCID: PMC10027087 DOI: 10.1152/ajpcell.00519.2022] [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: 11/15/2022] [Revised: 01/18/2023] [Accepted: 01/19/2023] [Indexed: 02/01/2023]
Abstract
Individual limb muscles have characteristic representation and spatial distribution of muscle fiber types (one slow and up to three fast isoforms) appropriate to their unique anatomical location and function. This distribution can be altered by physiological stimuli such as training (i.e., for increased endurance or force) or pathological conditions such as aging. Our group previously showed that ephrin-A3 is expressed only on slow myofibers, and that adult mice lacking ephrin-A3 have dramatically reduced numbers of slow myofibers due to postnatal innervation of previously slow myofibers by fast motor neurons. In this study, fiber type composition of hindlimb muscles of aged and denervated/reinnervated C57BL/6 and ephrin-A3-/- mice was analyzed to determine whether the loss of slow myofibers persists across the lifespan. Surprisingly, fiber-type composition of ephrin-A3-/- mouse muscles at two years of age was nearly indistinguishable from age-matched C57BL/6 mice. After challenge with nerve crush, the percentage of IIa and I/IIa hybrid myofibers increased significantly in aged ephrin-A3-/- mice. While EphA8, the receptor for ephrin-A3, is present at all neuromuscular junctions (NMJs) on fast fibers in 3-6 mo old C57BL/6 and ephrin-A3-/- mice, this exclusive localization is lost with aging, with EphA8 expression now found on a subset of NMJs on some slow muscle fibers. This return to appropriate fiber-type distribution given time and under use reinforces the role of activity in determining fiber-type representation and suggests that, rather than being a passive baseline, the developmentally and evolutionarily selected fiber type pattern may instead be actively reinforced by daily living.
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Affiliation(s)
- Robert W. Arpke
- Division of Biological Sciences, University of Missouri, Columbia, Missouri, United States
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, United States
| | - Timothy C. Moritz
- Division of Biological Sciences, University of Missouri, Columbia, Missouri, United States
| | - Kevin L. Hahn
- Division of Biological Sciences, University of Missouri, Columbia, Missouri, United States
| | - Danny A. Stark
- Division of Biological Sciences, University of Missouri, Columbia, Missouri, United States
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, United States
| | - Eric Villalón
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, United States
| | - Christian L. Lorson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, United States
| | - DDW Cornelison
- Division of Biological Sciences, University of Missouri, Columbia, Missouri, United States
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, United States
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Pollock N, Macpherson PC, Staunton CA, Hemmings K, Davis CS, Owen ED, Vasilaki A, Van Remmen H, Richardson A, McArdle A, Brooks SV, Jackson MJ. Deletion of Sod1 in Motor Neurons Exacerbates Age-Related Changes in Axons and Neuromuscular Junctions in Mice. eNeuro 2023; 10:ENEURO.0086-22.2023. [PMID: 36810149 PMCID: PMC10026931 DOI: 10.1523/eneuro.0086-22.2023] [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: 02/24/2022] [Revised: 02/03/2023] [Accepted: 02/05/2023] [Indexed: 02/23/2023] Open
Abstract
Whole-body knock-out of Cu,Zn superoxide dismutase (Sod1KO) results in accelerated, age-related loss of muscle mass and function associated with neuromuscular junction (NMJ) breakdown similar to sarcopenia. In order to determine whether altered redox in motor neurons underlies this phenotype, an inducible neuron-specific deletion of Sod1 (i-mnSod1KO) was compared with wild-type (WT) mice of different ages (adult, mid-age, and old) and whole-body Sod1KO mice. Nerve oxidative damage, motor neuron numbers and structural changes to neurons and NMJ were examined. Tamoxifen-induced deletion of neuronal Sod1 from two months of age. No specific effect of a lack of neuronal Sod1 was seen on markers of nerve oxidation (electron paramagnetic resonance of an in vivo spin probe, protein carbonyl, or protein 3-nitrotyrosine contents). i-mnSod1KO mice showed increased denervated NMJ, reduced numbers of large axons and increased number of small axons compared with old WT mice. A large proportion of the innervated NMJs in old i-mnSod1KO mice displayed a simpler structure than that seen in adult or old WT mice. Thus, previous work showed that neuronal deletion of Sod1 induced exaggerated loss of muscle in old mice, and we report that this deletion leads to a specific nerve phenotype including reduced axonal area, increased proportion of denervated NMJ, and reduced acetyl choline receptor complexity. Other changes in nerve and NMJ structure seen in the old i-mnSod1KO mice reflect aging of the mice.
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Affiliation(s)
- N Pollock
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, and MRC-Versus Arthritis Centre for Integrated Research into Musculoskeletal Ageing (CIMA), Liverpool, L7 8TX, UK
| | - P C Macpherson
- Molecular and Integrative Physiology, University of Michigan, Ann Arbor, 48109 MI
| | - C A Staunton
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, and MRC-Versus Arthritis Centre for Integrated Research into Musculoskeletal Ageing (CIMA), Liverpool, L7 8TX, UK
| | - K Hemmings
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, and MRC-Versus Arthritis Centre for Integrated Research into Musculoskeletal Ageing (CIMA), Liverpool, L7 8TX, UK
| | - C S Davis
- Molecular and Integrative Physiology, University of Michigan, Ann Arbor, 48109 MI
| | - E D Owen
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, and MRC-Versus Arthritis Centre for Integrated Research into Musculoskeletal Ageing (CIMA), Liverpool, L7 8TX, UK
| | - A Vasilaki
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, and MRC-Versus Arthritis Centre for Integrated Research into Musculoskeletal Ageing (CIMA), Liverpool, L7 8TX, UK
| | - H Van Remmen
- Oklahoma Medical Research Foundation (OMRF), Oklahoma City, 73104, OK
| | - A Richardson
- University of Oklahoma Health Science Center (OUHSC), Oklahoma City, 73104, OK
| | - A McArdle
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, and MRC-Versus Arthritis Centre for Integrated Research into Musculoskeletal Ageing (CIMA), Liverpool, L7 8TX, UK
| | - S V Brooks
- Molecular and Integrative Physiology, University of Michigan, Ann Arbor, 48109 MI
| | - M J Jackson
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, and MRC-Versus Arthritis Centre for Integrated Research into Musculoskeletal Ageing (CIMA), Liverpool, L7 8TX, UK
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24
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Use of a novel technique to assess impact of age-related denervation on mouse soleus muscle function. Biogerontology 2023; 24:377-390. [PMID: 36790689 PMCID: PMC10147802 DOI: 10.1007/s10522-023-10021-6] [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: 11/17/2022] [Accepted: 01/26/2023] [Indexed: 02/16/2023]
Abstract
Denervation contributes to loss of force-generating capacity in aged skeletal muscles, but problems with quantification of denervated fibers mean the precise impact of denervation on muscle function remains unclear. This study therefore looked to develop a reliable assay for identifying denervated muscle fibers, and used this to explore the impact of denervation on age-related force-generation in mouse skeletal muscle. Thirteen young (6-month-old) and 10 old (24-months-old) C57Bl/6 J female mice were utilized. Anaesthetized mice were infused with the fluorescent deoxyglucose analog 2[N-(7-nitrobenz-2-oxa-1,2-diaxol-4-yl)amino]-2-deoxyglucose (2-NBDG) and the tibial nerve was repeatedly stimulated to label active skeletal muscle fibers by activity-dependent uptake of 2-NBDG. Data on muscle force generation were acquired as part of the stimulation routine. Labeled muscles were removed, snap frozen, sectioned, and slide mounted. Sections were imaged to show accumulation of 2-NBDG in activated fibers and lack of 2-NBDG accumulation in quiescent (denervated) fibers, then processed using immunohistochemistry to allow collection of data on fiber number and morphology. Soleus muscles from older mice had nine times as many denervated fibers as those from young mice (average n = 36 vs 4, old vs young). Older muscles developed significantly more passive force and less specific force, but denervation only partly accounted for age-related deficits in specific force. Further investigations are required to definitively identify contributors to the decrease in force generation that remain unaccounted for.
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25
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James E, Goodall S, Nichols S, Walker K, Carroll S, O'Doherty AF, Ingle L. Serum transthyretin and aminotransferases are associated with lean mass in people with coronary heart disease: Further insights from the CARE-CR study. Front Med (Lausanne) 2023; 10:1094733. [PMID: 36891188 PMCID: PMC9986330 DOI: 10.3389/fmed.2023.1094733] [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: 11/10/2022] [Accepted: 02/01/2023] [Indexed: 02/22/2023] Open
Abstract
Background Low muscle mass disproportionately affects people with coronary heart disease compared to healthy controls but is under-researched and insufficiently treated. Inflammation, poor nutrition, and neural decline might contribute to low muscle mass. This study aimed to assess circulatory biomarkers related to these mechanisms [albumin, transthyretin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and C-terminal agrin fragment] and their relationship with muscle mass in people with coronary heart disease. Our findings could be beneficial to indicate mechanisms of sarcopenia, detect sarcopenia, and evaluate treatment. Methods Serum blood samples from people with coronary heart disease were analysed for biomarker concentrations using enzyme-linked immunosorbent assays. Skeletal muscle mass was estimated using dual X-ray absorptiometry derived appendicular lean mass and reported as skeletal muscle index (SMI; kg m-2), and as a proportion of total body mass [appendicular skeletal mass (ASM%)]. Low muscle mass was defined as a SMI <7.0 and <6.0 kg m-2, or ASM% <25.72 and <19.43% for men and women, respectively. Associations between biomarkers and lean mass were adjusted for age and inflammation. Results Sixty-four people were assessed; 14 (21.9%) had low muscle mass. People with low muscle mass had lower transthyretin (effect size 0.34, p = 0.007), ALT (effect size 0.34, p = 0.008), and AST (effect size 0.26, p = 0.037) concentrations, compared to those with normal muscle mass. SMI was associated with inflammation-corrected ALT (r = 0.261, p = 0.039) and with inflammation- and age-adjusted AST/ALT ratio (r = -0.257, p = 0.044). Albumin and C-terminal agrin fragment were not associated with muscle mass indices. Conclusion Circulatory transthyretin, ALT and AST were associated with low muscle mass in people with coronary heart disease. Low concentrations of these biomarkers might indicate that low muscle mass is partially explained by poor nutrition and high inflammation in this cohort. Targeted treatments to address these factors could be considered for people with coronary heart disease.
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Affiliation(s)
- Emily James
- Department of Sport, Exercise and Rehabilitation, Northumbria University, Newcastle upon Tyne, United Kingdom.,Diabetes Research Centre, University of Leicester, Leicester, United Kingdom.,NIHR Leicester Biomedical Research Centre, Leicester, United Kingdom
| | - Stuart Goodall
- Department of Sport, Exercise and Rehabilitation, Northumbria University, Newcastle upon Tyne, United Kingdom
| | - Simon Nichols
- Sport and Physical Activity Research Group, Sheffield Hallam University, Sheffield, United Kingdom.,Advanced Wellbeing Research Centre, Sheffield Hallam University, Sheffield, United Kingdom
| | - Karen Walker
- Department of Applied Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
| | - Sean Carroll
- School of Sport, Exercise and Rehabilitation Sciences, University of Hull, Hull, United Kingdom
| | - Alasdair F O'Doherty
- Department of Sport, Exercise and Rehabilitation, Northumbria University, Newcastle upon Tyne, United Kingdom
| | - Lee Ingle
- School of Sport, Exercise and Rehabilitation Sciences, University of Hull, Hull, United Kingdom
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26
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Fogarty MJ, Sieck GC. Aging affects the number and morphological heterogeneity of rat phrenic motor neurons and phrenic motor axons. Physiol Rep 2023; 11:e15587. [PMID: 36695744 PMCID: PMC9875821 DOI: 10.14814/phy2.15587] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 01/06/2023] [Accepted: 01/08/2023] [Indexed: 01/26/2023] Open
Abstract
Diaphragm muscle (DIAm) motor units comprise a phrenic motor neuron (PhMN), the phrenic nerve and the muscle fibers innervated, with the size of PhMNs and axons characteristic of motor unit type. Smaller PhMNs and their axons comprise slow (type S) and fatigue-resistant (type FR) DIAm motor units, while larger PhMNs and their axons comprise more fatigable (type FF) motor units. With aging, we have shown a loss of larger PhMNs, consistent with selective atrophy of type IIx/IIb DIAm fibers and reduced maximum DIAm force. In the present study, we hypothesized that with aging there is a loss of larger myelinated phrenic α motor axons. Female and male young (6 months) and old (24 months) Fischer 344 rats were studied. PhMNs were retrogradely labeled by intrapleural injection of 488-conjugated CTB. The phrenic nerves were excised ~1 cm from the DIAm insertion and mounted in resin, and phrenic α motor axons were delineated based on size (i.e., >4 μm diameters). In older rats, the number of larger PhMNs and larger phrenic α motor axons were reduced. There were no differences in non-α axons. In addition, there was evidence of demyelination of larger phrenic α motor axons in older rats. Together, these findings are consistent with the selective age-related vulnerability of larger PhMNs and denervation of type FF motor units, which may underlie DIAm sarcopenia.
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Affiliation(s)
- Matthew J. Fogarty
- Department of Physiology & Biomedical EngineeringMayo ClinicRochesterMinnesotaUSA
| | - Gary C. Sieck
- Department of Physiology & Biomedical EngineeringMayo ClinicRochesterMinnesotaUSA
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27
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Roberts BM, Deemer SE, Smith DL, Mobley JA, Musi N, Plaisance EP. Effects of an exogenous ketone ester using multi-omics in skeletal muscle of aging C57BL/6J male mice. Front Nutr 2022; 9:1041026. [PMID: 36458175 PMCID: PMC9707703 DOI: 10.3389/fnut.2022.1041026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Accepted: 10/25/2022] [Indexed: 11/17/2022] Open
Abstract
Exogenous ketone ester supplementation provides a means to increase circulating ketone concentrations without the dietary challenges imposed by ketogenic diets. Our group has shown that oral R,S-1,3, butanediol diacetoacetate (BD-AcAc2) consumption results in body weight loss or maintenance with moderate increases in circulating ketones. We have previously shown a diet consisting of 25% BD-AcAc2 can maintain lean body mass (LBM) and induce fat mass (FM) loss in young, healthy male mice, but the underlying mechanisms are still unknown. Therefore, the purpose of this study was to determine if a diet consisting of 25% BD-AcAc2 (ketone ester, KE) would alter body composition, transcriptional regulation, the proteome, and the lipidome of skeletal muscle in aged mice. We hypothesized that the KE group would remain weight stable with improvements in body composition compared to controls, resulting in a healthy aging phenotype. Male C57BL/6J mice (n = 16) were purchased from Jackson Laboratories at 72 weeks of age. After 1 week of acclimation, mice were weighed and randomly assigned to one of two groups (n = 8 per group): control (CON) or KE. A significant group by time interaction was observed for body weight (P < 0.001), with KE fed mice weighing significantly less than CON. FM increased over time in the control group but was unchanged in the KE group. Furthermore, LBM was not different between CON and KE mice despite KE mice weighing less than CON mice. Transcriptional analysis of skeletal muscle identified 6 genes that were significantly higher and 21 genes that were significantly lower in the KE group compared to CON. Lipidomic analysis of skeletal muscle identified no differences between groups for any lipid species, except for fatty acyl chains in triacylglycerol which was 46% lower in the KE group. Proteomics analysis identified 44 proteins that were different between groups, of which 11 were lower and 33 were higher in the KE group compared to CON. In conclusion, 72-week-old male mice consuming the exogenous KE, BD-AcAc2, had lower age-related gains in body weight and FM compared to CON mice. Furthermore, transcriptional and proteomics data suggest a signature in skeletal muscle of KE-treated mice consistent with markers of improved skeletal muscle regeneration, improved electron transport chain utilization, and increased insulin sensitivity.
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Affiliation(s)
- Brandon M. Roberts
- Department of Human Studies, Division of Molecular and Translational Biomedicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Sarah E. Deemer
- Department of Kinesiology, Health Promotion, and Recreation, University of North Texas, Denton, TX, United States
| | - Daniel L. Smith
- Department of Nutrition Sciences, Division of Molecular and Translational Biomedicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - James A. Mobley
- Department of Anesthesiology and Perioperative Medicine, Division of Molecular and Translational Biomedicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Nicolas Musi
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center San Antonio, San Antonio, TX, United States
- San Antonio Geriatric Research, Education, and Clinical Center, San Antonio, TX, United States
| | - Eric P. Plaisance
- Department of Human Studies, Division of Molecular and Translational Biomedicine, University of Alabama at Birmingham, Birmingham, AL, United States
- *Correspondence: Eric P. Plaisance,
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28
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Brown JL, Peelor FF, Georgescu C, Wren JD, Kinter M, Tyrrell VJ, O'Donnell VB, Miller BF, Van Remmen H. Lipid hydroperoxides and oxylipins are mediators of denervation induced muscle atrophy. Redox Biol 2022; 57:102518. [PMID: 36283174 PMCID: PMC9593840 DOI: 10.1016/j.redox.2022.102518] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 10/18/2022] [Accepted: 10/19/2022] [Indexed: 01/14/2023] Open
Abstract
Loss of innervation is a key driver of age associated muscle atrophy and weakness (sarcopenia). Our laboratory has previously shown that denervation induced atrophy is associated with the generation of mitochondrial hydroperoxides and lipid mediators produced downstream of cPLA2 and 12/15 lipoxygenase (12/15-LOX). To define the pathological impact of lipid hydroperoxides generated in denervation-induced atrophy in vivo, we treated mice with liproxstatin-1, a lipid hydroperoxide scavenger. We treated adult male mice with 5 mg/kg liproxstain-1 or vehicle one day prior to sciatic nerve transection and daily for 7 days post-denervation before tissue analysis. Liproxstatin-1 treatment protected gastrocnemius mass and fiber cross sectional area (∼40% less atrophy post-denervation in treated versus untreated mice). Mitochondrial hydroperoxide generation was reduced 80% in vitro and by over 65% in vivo by liproxstatin-1 treatment in denervated permeabilized muscle fibers and decreased the content of 4-HNE by ∼25% post-denervation. Lipidomic analysis revealed detectable levels of 25 oxylipins in denervated gastrocnemius muscle and significantly increased levels for eight oxylipins that are generated by metabolism of fatty acids through 12/15-LOX. Liproxstatin-1 treatment reduced the level of three of the eight denervation-induced oxylipins, specifically 15-HEPE, 13-HOTrE and 17-HDOHE. Denervation elevated protein degradation rates in muscle and treatment with liproxstatin-1 reduced rates of protein breakdown in denervated muscle. In contrast, protein synthesis rates were unchanged by denervation. Targeted proteomics revealed a number of proteins with altered expression after denervation but no effect of liproxstain-1. Transcriptomic analysis revealed 203 differentially expressed genes in denervated muscle from vehicle or liproxstatin-1 treated mice, including ER stress, nitric oxide signaling, Gαi signaling, glucocorticoid receptor signaling, and other pathways. Overall, these data suggest lipid hydroperoxides and oxylipins are key drivers of increased protein breakdown and muscle loss associated with denervation induced atrophy and a potential target for sarcopenia intervention.
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Affiliation(s)
- Jacob L Brown
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, United States; Oklahoma City VA Medical Center, Oklahoma City, OK, 73104, United States
| | - Fredrick F Peelor
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, United States
| | - Constantin Georgescu
- Division of Genomics and Data Sciences, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, United States
| | - Jonathan D Wren
- Division of Genomics and Data Sciences, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, United States
| | - Michael Kinter
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, United States
| | - Victoria J Tyrrell
- Systems Immunity Research Institute, School of Medicine, Cardiff University, Cardiff, CF14 4XN, United Kingdom
| | - Valerie B O'Donnell
- Systems Immunity Research Institute, School of Medicine, Cardiff University, Cardiff, CF14 4XN, United Kingdom
| | - Benjamin F Miller
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, United States; Oklahoma City VA Medical Center, Oklahoma City, OK, 73104, United States
| | - Holly Van Remmen
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, United States; Oklahoma City VA Medical Center, Oklahoma City, OK, 73104, United States.
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Palzkill VR, Thome T, Murillo AL, Khattri RB, Ryan TE. Increasing plasma L-kynurenine impairs mitochondrial oxidative phosphorylation prior to the development of atrophy in murine skeletal muscle: A pilot study. Front Physiol 2022; 13:992413. [PMID: 36246103 PMCID: PMC9562971 DOI: 10.3389/fphys.2022.992413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 08/22/2022] [Indexed: 11/14/2022] Open
Abstract
Introduction: L-Kynurenine (L-Kyn), a product of tryptophan (Trp) catabolism, has been linked with impairments in walking speed, muscle strength/size, and physical function. The purpose of this pilot study was to develop a dietary model that elevates plasma L-Kyn levels in mice and characterize its impact on muscle health and function. Methods: Four-month-old C57BL6J male mice were randomized to either a L-Kyn supplemented (150 mg/kg) or chow diet for 10 weeks. Plasma L-Kyn and Trp levels were measured via mass spectrometry. Primary outcomes included assessments of muscle weights, myofiber cross-sectional area (CSA), nerve-stimulated contractile performance, and mitochondrial oxidative phosphorylation (OXPHOS) and hydrogen peroxide (H2O2) production. Additional experiments in cultured myotubes explored the impact of enhancing L-Kyn metabolism. Results: Mice randomized to the L-Kyn diet displayed significant increases in plasma L-Kyn levels (p = 0.0028) and the L-Kyn/Trp ratio (p = 0.011) when compared to chow fed mice. Food intake and body weights were not different between groups. There were no detectable differences in muscle weights, myofiber CSA, or contractile performance. L-Kyn fed mice displayed reductions in mitochondrial OXPHOS (p = 0.05) and maximal ADP-stimulated respiration (p = 0.0498). In cultured myotubes, overexpression of peroxisome proliferator-activated receptor-gamma coactivator 1 alpha prevented atrophy and proteolysis, as well as deficits in mitochondrial respiration with L-Kyn treatment. Conclusion: Dietary feeding of L-Kyn increases plasma L-Kyn levels and the L-Kyn/Trp ratio in healthy male mice. Mitochondrial impairments in muscle were observed in mice with elevated L-Kyn without changes in muscle size or function. Enhancing L-Kyn metabolism can protect against these effects in culture myotubes.
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Affiliation(s)
- Victoria R. Palzkill
- Department of Applied Physiology and Kinesiology, Gainesville, FL, United States
| | - Trace Thome
- Department of Applied Physiology and Kinesiology, Gainesville, FL, United States
| | - Ania L. Murillo
- Department of Applied Physiology and Kinesiology, Gainesville, FL, United States
| | - Ram B. Khattri
- Department of Applied Physiology and Kinesiology, Gainesville, FL, United States
| | - Terence E. Ryan
- Department of Applied Physiology and Kinesiology, Gainesville, FL, United States
- Center for Exercise Science, Gainesville, FL, United States
- Myology Institute, University of Florida, Gainesville, FL, United States
- *Correspondence: Terence E. Ryan,
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Hulen J, Kenny D, Black R, Hallgren J, Hammond KG, Bredahl EC, Wickramasekara RN, Abel PW, Stessman HAF. KMT5B is required for early motor development. Front Genet 2022; 13:901228. [PMID: 36035149 PMCID: PMC9411648 DOI: 10.3389/fgene.2022.901228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 07/11/2022] [Indexed: 11/13/2022] Open
Abstract
Disruptive variants in lysine methyl transferase 5B (KMT5B/SUV4-20H1) have been identified as likely-pathogenic among humans with neurodevelopmental phenotypes including motor deficits (i.e., hypotonia and motor delay). However, the role that this enzyme plays in early motor development is largely unknown. Using a Kmt5b gene trap mouse model, we assessed neuromuscular strength, skeletal muscle weight (i.e., muscle mass), neuromuscular junction (NMJ) structure, and myofiber type, size, and distribution. Tests were performed over developmental time (postnatal days 17 and 44) to represent postnatal versus adult structures in slow- and fast-twitch muscle types. Prior to the onset of puberty, slow-twitch muscle weight was significantly reduced in heterozygous compared to wild-type males but not females. At the young adult stage, we identified decreased neuromuscular strength, decreased skeletal muscle weights (both slow- and fast-twitch), increased NMJ fragmentation (in slow-twitch muscle), and smaller myofibers in both sexes. We conclude that Kmt5b haploinsufficiency results in a skeletal muscle developmental deficit causing reduced muscle mass and body weight.
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Affiliation(s)
- Jason Hulen
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE, United States
| | - Dorothy Kenny
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE, United States
| | - Rebecca Black
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE, United States
| | - Jodi Hallgren
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE, United States
| | - Kelley G. Hammond
- Department of Exercise Science, College of Arts and Sciences, Creighton University, Omaha, NE, United States
| | - Eric C. Bredahl
- Department of Exercise Science, College of Arts and Sciences, Creighton University, Omaha, NE, United States
| | - Rochelle N. Wickramasekara
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE, United States
- Molecular Diagnostic Laboratory, Boys Town National Research Hospital, Omaha, NE, United States
| | - Peter W. Abel
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE, United States
| | - Holly A. F. Stessman
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE, United States
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Cardiac troponin T and autoimmunity in skeletal muscle aging. GeroScience 2022; 44:2025-2045. [PMID: 35034279 PMCID: PMC9616986 DOI: 10.1007/s11357-022-00513-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 01/05/2022] [Indexed: 01/03/2023] Open
Abstract
Age-related muscle mass and strength decline (sarcopenia) impairs the performance of daily living activities and can lead to mobility disability/limitation in older adults. Biological pathways in muscle that lead to mobility problems have not been fully elucidated. Immunoglobulin G (IgG) infiltration in muscle is a known marker of increased fiber membrane permeability and damage vulnerability, but whether this translates to impaired function is unknown. Here, we report that IgG1 and IgG4 are abundantly present in the skeletal muscle (vastus lateralis) of ~ 50% (11 out of 23) of older adults (> 65 years) examined. Skeletal muscle IgG1 was inversely correlated with physical performance (400 m walk time: r = 0.74, p = 0.005; SPPB score: r = - 0.73, p = 0.006) and muscle strength (r = - 0.6, p = 0.05). In a murine model, IgG was found to be higher in both muscle and blood of older, versus younger, C57BL/6 mice. Older mice with a higher level of muscle IgG had lower motor activity. IgG in mouse muscle co-localized with cardiac troponin T (cTnT) and markers of complement activation and apoptosis/necroptosis. Skeletal muscle-inducible cTnT knockin mice also showed elevated IgG in muscle and an accelerated muscle degeneration and motor activity decline with age. Most importantly, anti-cTnT autoantibodies were detected in the blood of cTnT knockin mice, old mice, and older humans. Our findings suggest a novel cTnT-mediated autoimmune response may be an indicator of sarcopenia.
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Redox Control of Signalling Responses to Contractile Activity and Ageing in Skeletal Muscle. Cells 2022; 11:cells11101698. [PMID: 35626735 PMCID: PMC9139227 DOI: 10.3390/cells11101698] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 05/13/2022] [Accepted: 05/16/2022] [Indexed: 02/06/2023] Open
Abstract
Research over almost 40 years has established that reactive oxygen species are generated at different sites in skeletal muscle and that the generation of these species is increased by various forms of exercise. Initially, this was thought to be potentially deleterious to skeletal muscle and other tissues, but more recent data have identified key roles of these species in muscle adaptations to exercise. The aim of this review is to summarise our current understanding of these redox signalling roles of reactive oxygen species in mediating responses of muscle to contractile activity, with a particular focus on the effects of ageing on these processes. In addition, we provide evidence that disruption of the redox status of muscle mitochondria resulting from age-associated denervation of muscle fibres may be an important factor leading to an attenuation of some muscle responses to contractile activity, and we speculate on potential mechanisms involved.
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33
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Tran KN, Choi JI. Mimic microgravity effect on muscle transcriptome under ionizing radiation. LIFE SCIENCES IN SPACE RESEARCH 2022; 32:96-104. [PMID: 35065767 DOI: 10.1016/j.lssr.2021.12.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 11/30/2021] [Accepted: 12/08/2021] [Indexed: 06/14/2023]
Abstract
Spaceflight imposes the risk of skeletal muscle atrophy for astronauts. Two main factors of a spaceflight that results in deleterious effects are microgravity and cosmic rays in outer space. To study spaceflight-induced muscle atrophy with ground-based models, we performed two models of microgravity, tail suspension and denervation, in a low dose radiation environment and studied transcriptional changes in rat soleus muscle using microarrays. Soleus muscle from rats in the denervation group had greater expression changes compared to that found in rats from the tail suspension group. However, there was a very similar pattern of expression of differentially expressed genes (DEGs) in both models. In total, we identified 144 differentially expressed genes common in both models. Our study yielded two main findings. First, a large number of genes involved in energy metabolism were transcriptionally suppressed including those involved in fatty acid transport and beta-oxidation, and oxidative phosphorylation. Second, slow-twitch contractile protein encoding genes were down-regulated while there was an up-regulation in the fast-twitch type transcription. These results were consistent with other spaceflight studies on the effects on muscle cells, hence showed the potential of our ground-based models in studying spaceflight effects. The genes that might be involved in spaceflight effects will serve as candidate genes for future studies in understanding the mechanism of spaceflight-induced muscle atrophy and result in the development of effective countermeasures.
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Affiliation(s)
- Kim Ngan Tran
- Department of Biotechnology and Bioengineering, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Jong-Il Choi
- Department of Biotechnology and Bioengineering, Chonnam National University, Gwangju 61186, Republic of Korea.
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34
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Trevino MA, Dimmick HL, Parra ME, Sterczala AJ, Miller JD, Deckert JA, Gallagher PM, Fry AC, Weir JP, Herda TJ. Effects of continuous cycling training on motor unit firing rates, input excitation, and myosin heavy chain of the vastus lateralis in sedentary females. Exp Brain Res 2022; 240:825-839. [DOI: 10.1007/s00221-021-06278-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 11/13/2021] [Indexed: 11/25/2022]
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35
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Yang Q, Chan P. Skeletal Muscle Metabolic Alternation Develops Sarcopenia. Aging Dis 2022; 13:801-814. [PMID: 35656108 PMCID: PMC9116905 DOI: 10.14336/ad.2021.1107] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 11/28/2021] [Indexed: 11/23/2022] Open
Abstract
Sarcopenia is a new type of senile syndrome with progressive skeletal muscle mass loss with age, accompanied by decreased muscle strength and/or muscle function. Sarcopenia poses a serious threat to the health of the elderly and increases the burden of family and society. The underlying pathophysiological mechanisms of sarcopenia are still unclear. Recent studies have shown that changes of skeletal muscle metabolism are the risk factors for sarcopenia. Furthermore, the importance of the skeletal muscle metabolic microenvironment in regulating satellite cells (SCs) is gaining significant attention. Skeletal muscle metabolism has intrinsic relationship with the regulation of skeletal muscle mass and regeneration. This review is to discuss recent findings regarding skeletal muscle metabolic alternation and the development of sarcopenia, hoping to contribute better understanding and treatment of sarcopenia.
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Affiliation(s)
- Qiumei Yang
- Department of Neurology, Geriatrics and Neurobiology, National Clinical Research Center of Geriatric Disorders, Xuanwu Hospital of Capital Medical University, Beijing, China.
- Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China.
| | - Piu Chan
- Department of Neurology, Geriatrics and Neurobiology, National Clinical Research Center of Geriatric Disorders, Xuanwu Hospital of Capital Medical University, Beijing, China.
- Clinical Center for Parkinson’s Disease, Capital Medical University, Beijing Institute of Geriatrics, Beijing, China.
- Key Laboratory for Neurodegenerative Disease of the Ministry of Education, Beijing Key Laboratory for Parkinson’s Disease, Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China.
- Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China.
- Correspondence should be addressed to: Dr. Piu Chan, Department of Neurobiology, Xuanwu Hospital of Capital Medical University, 45 Changchun Road, Beijing 100053, China. .
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36
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Mytidou C, Koutsoulidou A, Zachariou M, Prokopi M, Kapnisis K, Spyrou GM, Anayiotos A, Phylactou LA. Age-Related Exosomal and Endogenous Expression Patterns of miR-1, miR-133a, miR-133b, and miR-206 in Skeletal Muscles. Front Physiol 2021; 12:708278. [PMID: 34867435 PMCID: PMC8637414 DOI: 10.3389/fphys.2021.708278] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 10/26/2021] [Indexed: 12/12/2022] Open
Abstract
Skeletal muscle growth and maintenance depend on two tightly regulated processes, myogenesis and muscle regeneration. Both processes involve a series of crucial regulatory molecules including muscle-specific microRNAs, known as myomiRs. We recently showed that four myomiRs, miR-1, miR-133a, miR-133b, and miR-206, are encapsulated within muscle-derived exosomes and participate in local skeletal muscle communication. Although these four myomiRs have been extensively studied for their function in muscles, no information exists regarding their endogenous and exosomal levels across age. Here we aimed to identify any age-related changes in the endogenous and muscle-derived exosomal myomiR levels during acute skeletal muscle growth. The four endogenous and muscle-derived myomiRs were investigated in five skeletal muscles (extensor digitorum longus, soleus, tibialis anterior, gastrocnemius, and quadriceps) of 2-week–1-year-old wild-type male mice. The expression of miR-1, miR-133a, and miR-133b was found to increase rapidly until adolescence in all skeletal muscles, whereas during adulthood it remained relatively stable. By contrast, endogenous miR-206 levels were observed to decrease with age in all muscles, except for soleus. Differential expression of the four myomiRs is also inversely reflected on the production of two protein targets; serum response factor and connexin 43. Muscle-derived exosomal miR-1, miR-133a, and miR-133b levels were found to increase until the early adolescence, before reaching a plateau phase. Soleus was found to be the only skeletal muscle to release exosomes enriched in miR-206. In this study, we showed for the first time an in-depth longitudinal analysis of the endogenous and exosomal levels of the four myomiRs during skeletal muscle development. We showed that the endogenous expression and extracellular secretion of the four myomiRs are associated to the function and size of skeletal muscles as the mice age. Overall, our findings provide new insights for the myomiRs’ significant role in the first year of life in mice.
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Affiliation(s)
- Chrystalla Mytidou
- Department of Molecular Genetics, Function and Therapy, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus.,Cyprus School of Molecular Medicine, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Andrie Koutsoulidou
- Department of Molecular Genetics, Function and Therapy, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus.,Cyprus School of Molecular Medicine, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Margarita Zachariou
- Cyprus School of Molecular Medicine, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus.,Bioinformatics Department, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Marianna Prokopi
- Theramir Ltd., Limassol, Cyprus.,Department of Mechanical Engineering and Materials Science and Engineering, Cyprus University of Technology, Limassol, Cyprus
| | - Konstantinos Kapnisis
- Department of Mechanical Engineering and Materials Science and Engineering, Cyprus University of Technology, Limassol, Cyprus
| | - George M Spyrou
- Cyprus School of Molecular Medicine, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus.,Bioinformatics Department, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Andreas Anayiotos
- Department of Mechanical Engineering and Materials Science and Engineering, Cyprus University of Technology, Limassol, Cyprus
| | - Leonidas A Phylactou
- Department of Molecular Genetics, Function and Therapy, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus.,Cyprus School of Molecular Medicine, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
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Burke SK, Fenton AI, Konokhova Y, Hepple RT. Variation in muscle and neuromuscular junction morphology between atrophy-resistant and atrophy-prone muscles supports failed re-innervation in aging muscle atrophy. Exp Gerontol 2021; 156:111613. [PMID: 34740815 DOI: 10.1016/j.exger.2021.111613] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 09/24/2021] [Accepted: 10/21/2021] [Indexed: 10/19/2022]
Abstract
In advanced age, there is an accelerated decline in skeletal muscle mass that appears to be secondary to repeated cycles of denervation-reinnervation and eventually, failed reinnervation. However, whether variation in reinnervation capacity explains why some muscles are less vulnerable to age-related atrophy has not been addressed. In this study we examined changes in neuromuscular junction (NMJ) morphology, fiber cross-sectional area (CSA) and fiber type, accumulation of severely atrophied myofibers, and expression of a marker of denervation in four muscles that exhibit differences in the degree of age-related atrophy and which span the extremes of fiber type composition in 8 mo old (8 M) and 34 mo old (34 M) male Fischer 344 Brown Norway F1 hybrid rats. Aging muscle atrophy was most pronounced in the fast twitch gastrocnemius (Gas; 25%) and similar between extensor digitorum longus (EDL) and slow-twitch soleus (Sol) muscle (14-15%), whereas the slow-twitch adductor longus (AL) increased in mass by 21% between 8 M and 34 M (P < 0.05 for all). Only the Sol exhibited significant alterations in fiber type with aging, and there was a decrease in fiber CSA in the Gas, EDL, and Sol (P < 0.05) with aging that was not seen in the AL. Muscles that atrophied had an increased fraction of severely atrophic myofibers (P < 0.05), but this was not observed in the AL. The Gas and EDL both demonstrated a similar degree of age-related remodeling of pre- and post-synaptic NMJ components. On the other hand, pre- and post-synaptic morphology underwent greater changes with aging in the AL, and many of these same morphological variables were already greater in the Sol vs AL at 8 M, suggesting the Sol had already undergone substantial remodeling and may be nearing its adaptive limits. Consistent with this idea, analysis of NMJ morphology in Sol from 3 M rats exhibited similar values as 8 M AL, and the Sol demonstrated greater expression of the denervation marker neural cell adhesion molecule (NCAM) compared to the AL at 34 M. Collectively, our results are consistent with NMJ remodeling capacity being finite with aging and that maintained remodeling potential confers atrophy protection in aging skeletal muscle by reducing the degree of persistent denervation.
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Affiliation(s)
- Sarah K Burke
- Department of Physical Therapy, College of Public Health and Health Professions, University of Florida, Gainesville, FL, USA
| | - Andrew I Fenton
- Department of Physical Therapy, College of Public Health and Health Professions, University of Florida, Gainesville, FL, USA
| | - Yana Konokhova
- Division of Pulmonary, Critical Care & Sleep Medicine, Department of Medicine, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Russell T Hepple
- Department of Physical Therapy, College of Public Health and Health Professions, University of Florida, Gainesville, FL, USA.
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38
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Wilburn D, Ismaeel A, Machek S, Fletcher E, Koutakis P. Shared and distinct mechanisms of skeletal muscle atrophy: A narrative review. Ageing Res Rev 2021; 71:101463. [PMID: 34534682 DOI: 10.1016/j.arr.2021.101463] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 08/30/2021] [Accepted: 09/11/2021] [Indexed: 12/15/2022]
Abstract
Maintenance of skeletal muscle mass and function is an incredibly nuanced balance of anabolism and catabolism that can become distorted within different pathological conditions. In this paper we intend to discuss the distinct intracellular signaling events that regulate muscle protein atrophy for a given clinical occurrence. Aside from the common outcome of muscle deterioration, several conditions have at least one or more distinct mechanisms that creates unique intracellular environments that facilitate muscle loss. The subtle individuality to each of these given pathologies can provide both researchers and clinicians with specific targets of interest to further identify and increase the efficacy of medical treatments and interventions.
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Affiliation(s)
- Dylan Wilburn
- Department of Health, Human Performance, and Recreation, Baylor University, Waco, TX 76706, USA
| | - Ahmed Ismaeel
- Department of Biology, Baylor University, Waco, TX 76706, USA
| | - Steven Machek
- Department of Health, Human Performance, and Recreation, Baylor University, Waco, TX 76706, USA
| | - Emma Fletcher
- Department of Health, Human Performance, and Recreation, Baylor University, Waco, TX 76706, USA; Department of Biology, Baylor University, Waco, TX 76706, USA
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Su Y, Claflin DR, Huang M, Davis CS, Macpherson PCD, Richardson A, Van Remmen H, Brooks SV. Deletion of Neuronal CuZnSOD Accelerates Age-Associated Muscle Mitochondria and Calcium Handling Dysfunction That Is Independent of Denervation and Precedes Sarcopenia. Int J Mol Sci 2021; 22:ijms221910735. [PMID: 34639076 PMCID: PMC8509582 DOI: 10.3390/ijms221910735] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 09/23/2021] [Accepted: 09/29/2021] [Indexed: 12/17/2022] Open
Abstract
Skeletal muscle suffers atrophy and weakness with aging. Denervation, oxidative stress, and mitochondrial dysfunction are all proposed as contributors to age-associated muscle loss, but connections between these factors have not been established. We examined contractility, mitochondrial function, and intracellular calcium transients (ICTs) in muscles of mice throughout the life span to define their sequential relationships. We performed these same measures and analyzed neuromuscular junction (NMJ) morphology in mice with postnatal deletion of neuronal Sod1 (i-mn-Sod1-/- mice), previously shown to display accelerated age-associated muscle loss and exacerbation of denervation in old age, to test relationships between neuronal redox homeostasis, NMJ degeneration and mitochondrial function. In control mice, the amount and rate of the decrease in mitochondrial NADH during contraction was greater in middle than young age although force was not reduced, suggesting decreased efficiency of NADH utilization prior to the onset of weakness. Declines in both the peak of the ICT and force were observed in old age. Muscles of i-mn-Sod1-/- mice showed degeneration of mitochondrial and calcium handling functions in middle-age and a decline in force generation to a level not different from the old control mice, with maintenance of NMJ morphology. Together, the findings support the conclusion that muscle mitochondrial function decreases during aging and in response to altered neuronal redox status prior to NMJ deterioration or loss of mass and force suggesting mitochondrial defects contribute to sarcopenia independent of denervation.
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Affiliation(s)
- Yu Su
- Department of Neurosurgery, First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Dennis R Claflin
- Department of Surgery, Section of Plastic Surgery, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Meixiang Huang
- Department of Neurology, Second Xiangya Hospital, Central South University, Changsha 410011, China
| | - Carol S Davis
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Peter C D Macpherson
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Arlan Richardson
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- VA Medical Center, Oklahoma City, OK 73104, USA
| | - Holly Van Remmen
- VA Medical Center, Oklahoma City, OK 73104, USA
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
- Department of Physiology, Health Science Center, Oklahoma University, Oklahoma City, OK 73104, USA
| | - Susan V Brooks
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
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Lagerwaard B, Nieuwenhuizen AG, Bunschoten A, de Boer VC, Keijer J. Matrisome, innervation and oxidative metabolism affected in older compared with younger males with similar physical activity. J Cachexia Sarcopenia Muscle 2021; 12:1214-1231. [PMID: 34219410 PMCID: PMC8517362 DOI: 10.1002/jcsm.12753] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 04/29/2021] [Accepted: 06/08/2021] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Due to the interaction between skeletal muscle ageing and lifestyle factors, it is often challenging to attribute the decline in muscle mass and quality to either changes in lifestyle or to advancing age itself. Because many of the physiological factors affecting muscle mass and quality are modulated by physical activity and physical activity declines with age, the aim of this study is to better understand the effects of early ageing on muscle function by comparing a population of healthy older and young males with similar physical activity patterns. METHODS Eighteen older (69 ± 2.0 years) and 20 young (22 ± 2.0 years) males were recruited based on similar self-reported physical activity, which was verified using accelerometry measurements. Gene expression profiles of vastus lateralis biopsies obtained by RNA sequencing were compared, and key results were validated using quantitative polymerase chain reaction and western blot. RESULTS Total physical activity energy expenditure was similar between the young and old group (404 ± 215 vs. 411 ± 189 kcal/day, P = 0.11). Three thousand seven hundred ninety-seven differentially expressed coding genes (DEGs) were identified (adjusted P-value cut-off of <0.05), of which 1891 were higher and 1906 were lower expressed in the older muscle. The matrisome, innervation and inflammation were the main upregulated processes, and oxidative metabolism was the main downregulated process in old compared with young muscle. Lower protein levels of mitochondrial transcription factor A (TFAM, P = 0.030) and mitochondrial respiratory Complexes IV and II (P = 0.011 and P = 0.0009, respectively) were observed, whereas a trend was observed for Complex I (P = 0.062), in older compared with young muscle. Protein expression of Complexes I and IV was significantly correlated to mitochondrial capacity in the vastus lateralis as measured in vivo (P = 0.017, R2 = 0.42 and P = 0.030, R2 = 0.36). A trend for higher muscle-specific receptor kinase (MUSK) protein levels in the older group was observed (P = 0.08). CONCLUSIONS There are clear differences in the transcriptome signatures of the vastus lateralis muscle of healthy older and young males with similar physical activity levels, including significant differences at the protein level. By disentangling physical activity and ageing, we appoint early skeletal muscle ageing processes that occur despite similar physical activity. Improved understanding of these processes will be key to design targeted anti-ageing therapies.
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Affiliation(s)
- Bart Lagerwaard
- Human and Animal PhysiologyWageningen University and ResearchWageningenThe Netherlands
- TI Food and NutritionWageningenThe Netherlands
| | - Arie G. Nieuwenhuizen
- Human and Animal PhysiologyWageningen University and ResearchWageningenThe Netherlands
| | - Annelies Bunschoten
- Human and Animal PhysiologyWageningen University and ResearchWageningenThe Netherlands
| | - Vincent C.J. de Boer
- Human and Animal PhysiologyWageningen University and ResearchWageningenThe Netherlands
| | - Jaap Keijer
- Human and Animal PhysiologyWageningen University and ResearchWageningenThe Netherlands
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Schilling BK, Baker JS, Komatsu C, Marra KG. Intramuscular injection of skeletal muscle derived extracellular matrix mitigates denervation atrophy after sciatic nerve transection. J Tissue Eng 2021; 12:20417314211032491. [PMID: 34567507 PMCID: PMC8458676 DOI: 10.1177/20417314211032491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 06/23/2021] [Indexed: 11/17/2022] Open
Abstract
Peripheral nerve injury and the associated muscle atrophy has an estimated annual healthcare burden of $150 billion dollars in the United States. When considering the total annual health-related spending of $3.5 trillion, these pathologies alone occupy about 4.3%. The prevalence of these ailments is rooted, at least in part, in the lack of specific preventative therapies that can be administered to muscle while it remains in the denervated state. To address this, skeletal muscle-derived ECM (skECM) was injected directly in denervated muscle with postoperative analysis performed at 20 weeks, including gait analysis, force production, cytokine quantification, and histological analysis. skECM was shown to be superior against non-injected muscle controls showing no difference in contraction force to uninjured muscle at 20 weeks. Cytokines IL-1β, IL-18, and IFNγ appeared to mediate regeneration with statistical regression implicating these cytokines as strong predictors of muscle contraction, showing significant linear correlation.
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Affiliation(s)
- Benjamin K Schilling
- Department of Bioengineering, School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jocelyn S Baker
- Department of Bioengineering, School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Chiaki Komatsu
- Department of Plastic Surgery, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Kacey G Marra
- Department of Bioengineering, School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA.,Department of Plastic Surgery, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.,McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
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42
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Gilda JE, Ko JH, Elfassy AY, Tropp N, Parnis A, Ayalon B, Jhe W, Cohen S. A semiautomated measurement of muscle fiber size using the Imaris software. Am J Physiol Cell Physiol 2021; 321:C615-C631. [PMID: 34319828 DOI: 10.1152/ajpcell.00206.2021] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 07/25/2021] [Indexed: 11/22/2022]
Abstract
The size and shape of skeletal muscle fibers are affected by various physiological and pathological conditions, such as muscle atrophy, hypertrophy, regeneration, and dystrophies. Hence, muscle fiber cross-sectional area (CSA) is an important determinant of muscle health and plasticity. We adapted the Imaris software to automatically segment muscle fibers based on fluorescent labeling of the plasma membrane and measure muscle fiber CSA. Analysis of muscle cross sections by the Imaris semiautomated and manual approaches demonstrated a similar decrease in CSA of atrophying muscles from fasted mice compared with fed controls. In addition, we previously demonstrated that downregulation of the Ca2+-specific protease calpain-1 attenuates muscle atrophy. Accordingly, both the Imaris semiautomated and manual approaches showed a similar increase in CSA of fibers expressing calpain-1 shRNA compared with adjacent nontransfected fibers in the same muscle cross section. Although both approaches seem valid for measurements of muscle fiber size, the manual marking method is less preferable because it is highly time-consuming, subjective, and limits the number of cells that can be analyzed. The Imaris semiautomated approach is user-friendly, requires little training or optimization, and can be used to efficiently and accurately mark thousands of fibers in a short period. As a novel addition to the commonly used statistics, we also describe statistical tests that quantify the strength of an effect on fiber size, enabling detection of significant differences between skewed distributions that would otherwise not be detected using typical methods.
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Affiliation(s)
- Jennifer E Gilda
- Faculty of Biology, Technion Institute of Technology, Haifa, Israel
- Department of Physics & Astronomy, Center for 0D Nanofluidics, Seoul National University, Seoul, South Korea
| | - Joon-Hyuk Ko
- Faculty of Biology, Technion Institute of Technology, Haifa, Israel
- Department of Physics & Astronomy, Center for 0D Nanofluidics, Seoul National University, Seoul, South Korea
| | - Aviv-Yvonne Elfassy
- Faculty of Biology, Technion Institute of Technology, Haifa, Israel
- Department of Physics & Astronomy, Center for 0D Nanofluidics, Seoul National University, Seoul, South Korea
| | - Nadav Tropp
- Faculty of Biology, Technion Institute of Technology, Haifa, Israel
- Department of Physics & Astronomy, Center for 0D Nanofluidics, Seoul National University, Seoul, South Korea
| | - Anna Parnis
- Faculty of Biology, Technion Institute of Technology, Haifa, Israel
- Department of Physics & Astronomy, Center for 0D Nanofluidics, Seoul National University, Seoul, South Korea
| | - Bar Ayalon
- Faculty of Biology, Technion Institute of Technology, Haifa, Israel
- Department of Physics & Astronomy, Center for 0D Nanofluidics, Seoul National University, Seoul, South Korea
| | - Wonho Jhe
- Faculty of Biology, Technion Institute of Technology, Haifa, Israel
- Department of Physics & Astronomy, Center for 0D Nanofluidics, Seoul National University, Seoul, South Korea
| | - Shenhav Cohen
- Faculty of Biology, Technion Institute of Technology, Haifa, Israel
- Department of Physics & Astronomy, Center for 0D Nanofluidics, Seoul National University, Seoul, South Korea
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43
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Moreira-Pais A, Ferreira R, Oliveira PA, Duarte JA. Sarcopenia versus cancer cachexia: the muscle wasting continuum in healthy and diseased aging. Biogerontology 2021; 22:459-477. [PMID: 34324116 DOI: 10.1007/s10522-021-09932-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 07/21/2021] [Indexed: 12/15/2022]
Abstract
Muscle wasting is one of the major health problems in older adults and is traditionally associated to sarcopenia. Nonetheless, muscle loss may also occur in older adults in the presence of cancer, and in this case, it is associated to cancer cachexia. The clinical management of these conditions is a challenge due to, at least in part, the difficulties in their differential diagnosis. Thus, efforts have been made to better comprehend the pathogenesis of sarcopenia and cancer cachexia, envisioning the improvement of their clinical discrimination and treatment. To add insights on this topic, this review discusses the current knowledge on key molecular players underlying sarcopenia and cancer cachexia in a comparative perspective. Data retrieved from this analysis highlight that while sarcopenia is characterized by the atrophy of fast-twitch muscle fibers, in cancer cachexia an increase in the proportion of fast-twitch fibers appears to happen. The molecular drivers for these specificmuscle remodeling patterns are still unknown; however, among the predominant contributors to sarcopenia is the age-induced neuromuscular denervation, and in cancer cachexia, the muscle disuse experienced by cancer patients seems to play an important role. Moreover, inflammation appears to be more severe in cancer cachexia. Impairment of nutrition-related mediators may also contribute to sarcopenia and cancer cachexia, being distinctly modulated in each condition.
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Affiliation(s)
- Alexandra Moreira-Pais
- CIAFEL, Faculty of Sport, University of Porto, Dr. Plácido da Costa 91, 4200-450, Porto, Portugal. .,LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193, Aveiro, Portugal. .,Centre for Research and Technology of Agro Environmental and Biological Sciences (CITAB), Inov4Agro, University of Trás-os-Montes and Alto Douro (UTAD), Quinta de Prados, 5000-801, Vila Real, Portugal. .,Departamento de Química, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.
| | - Rita Ferreira
- LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193, Aveiro, Portugal
| | - Paula A Oliveira
- Centre for Research and Technology of Agro Environmental and Biological Sciences (CITAB), Inov4Agro, University of Trás-os-Montes and Alto Douro (UTAD), Quinta de Prados, 5000-801, Vila Real, Portugal
| | - José A Duarte
- CIAFEL, Faculty of Sport, University of Porto, Dr. Plácido da Costa 91, 4200-450, Porto, Portugal. .,Faculdade de Desporto, Universidade do Porto, Rua Dr. Plácido da Costa 91, 4200-450, Porto, Portugal. .,TOXRUN - Toxicology Research Unit, University Institute of Health Sciences, CESPU, CRL, Gandra, Portugal.
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44
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Fibro-Adipogenic Progenitors: Versatile keepers of skeletal muscle homeostasis, beyond the response to myotrauma. Semin Cell Dev Biol 2021; 119:23-31. [PMID: 34332886 DOI: 10.1016/j.semcdb.2021.07.013] [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: 05/10/2021] [Revised: 07/12/2021] [Accepted: 07/17/2021] [Indexed: 10/20/2022]
Abstract
While Fibro-Adipogenic Progenitors (FAPs) have been originally identified as muscle-interstitial mesenchymal cells activated in response to muscle injury and endowed with inducible fibrogenic and adipogenic potential, subsequent studies have expanded their phenotypic and functional repertoire and revealed their contribution to skeletal muscle response to a vast range of perturbations. Here we review the emerging contribution of FAPs to skeletal muscle responses to motor neuron injuries and to systemic physiological (e.g., exercise) or pathological metabolic (e.g., diabetes) perturbations. We also provide an initial blueprint of discrete sub-clusters of FAPs that are activated by specific perturbations and discuss their role in muscle adaptation to these conditions.
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45
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Dial AG, Monaco CMF, Grafham GK, Patel TP, Tarnopolsky MA, Hawke TJ. Impaired Function and Altered Morphology in the Skeletal Muscles of Adult Men and Women With Type 1 Diabetes. J Clin Endocrinol Metab 2021; 106:2405-2422. [PMID: 33890059 DOI: 10.1210/clinem/dgab261] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Indexed: 12/14/2022]
Abstract
CONTEXT Previous investigations on skeletal muscle health in type 1 diabetes (T1D) have generally focused on later stages of disease progression where comorbidities are present and are posited as a primary mechanism of muscle dysfunction. OBJECTIVE To investigate skeletal muscle function and morphology across the adult lifespan in those with and without T1D. DESIGN Participants underwent maximal contraction (MVC) testing, resting muscle biopsy, and venous blood sampling. SETTING Procedures in this study were undertaken at the McMaster University Medical Centre. PARTICIPANTS Sixty-five healthy adult (18-78 years old) men/males and women/females (T1D = 34; control = 31) matched for age/biological sex/body mass index; self-reported physical activity levels were included. MAIN OUTCOME MEASURES Our primary measure in this study was MVC, with supporting histological/immunofluorescent measures. RESULTS After 35 years of age ("older adults"), MVC declined quicker in T1D subjects compared to controls. Loss of strength in T1D was accompanied by morphological changes associated with accelerated aging. Type 1 myofiber grouping was higher in T1D, and the groups were larger and more numerous than in controls. Older T1D females exhibited more myofibers expressing multiple myosin heavy chain isoforms (hybrid fibers) than controls, another feature of accelerated aging. Conversely, T1D males exhibited a shift toward type 2 fibers, with less evidence of myofiber grouping or hybrid fibers. CONCLUSIONS These data suggest impairments to skeletal muscle function and morphology exist in T1D. The decline in strength with T1D is accelerated after 35 years of age and may be responsible for the earlier onset of frailty, which characterizes those with diabetes.
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Affiliation(s)
- Athan G Dial
- Dept of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
| | - Cynthia M F Monaco
- Dept of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
| | - Grace K Grafham
- Dept of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
| | - Tirth P Patel
- Dept of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
| | | | - Thomas J Hawke
- Dept of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
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46
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Gustafsson T, Ulfhake B. Sarcopenia: What Is the Origin of This Aging-Induced Disorder? Front Genet 2021; 12:688526. [PMID: 34276788 PMCID: PMC8285098 DOI: 10.3389/fgene.2021.688526] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 05/10/2021] [Indexed: 01/03/2023] Open
Abstract
We here review the loss of muscle function and mass (sarcopenia) in the framework of human healthspan and lifespan, and mechanisms involved in aging. The rapidly changing composition of the human population will impact the incidence and the prevalence of aging-induced disorders such as sarcopenia and, henceforth, efforts to narrow the gap between healthspan and lifespan should have top priority. There are substantial knowledge gaps in our understanding of aging. Heritability is estimated to account for only 25% of lifespan length. However, as we push the expected lifespan at birth toward those that we consider long-lived, the genetics of aging may become increasingly important. Linkage studies of genetic polymorphisms to both the susceptibility and aggressiveness of sarcopenia are still missing. Such information is needed to shed light on the large variability in clinical outcomes between individuals and why some respond to interventions while others do not. We here make a case for the concept that sarcopenia has a neurogenic origin and that in manifest sarcopenia, nerve and myofibers enter into a vicious cycle that will escalate the disease progression. We point to gaps in knowledge, for example the crosstalk between the motor axon, terminal Schwann cell, and myofiber in the denervation processes that leads to a loss of motor units and muscle weakness. Further, we argue that the operational definition of sarcopenia should be complemented with dynamic metrics that, along with validated biomarkers, may facilitate early preclinical diagnosis of individuals vulnerable to develop advanced sarcopenia. We argue that preventive measures are likely to be more effective to counter act aging-induced disorders than efforts to treat manifest clinical conditions. To achieve compliance with a prescription of preventive measures that may be life-long, we need to identify reliable predictors to design rational and convincing interventions.
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Affiliation(s)
- Thomas Gustafsson
- Division of Clinical Physiology, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Brun Ulfhake
- Division of Clinical Physiology, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
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47
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Allen MD, Dalton BH, Gilmore KJ, McNeil CJ, Doherty TJ, Rice CL, Power GA. Neuroprotective effects of exercise on the aging human neuromuscular system. Exp Gerontol 2021; 152:111465. [PMID: 34224847 DOI: 10.1016/j.exger.2021.111465] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Revised: 05/31/2021] [Accepted: 06/30/2021] [Indexed: 12/23/2022]
Abstract
Human biological aging from maturity to senescence is associated with a gradual loss of muscle mass and neuromuscular function. It is not until very old age (>80 years) however, that these changes often manifest into functional impairments. A driving factor underlying the age-related loss of muscle mass and function is the reduction in the number and quality of motor units (MUs). A MU consists of a single motoneuron, located either in the spinal cord or the brain stem, and all of the muscle fibres it innervates via its peripheral axon. Throughout the adult lifespan, MUs are slowly, but progressively lost. The compensatory process of collateral reinnervation attempts to recapture orphaned muscle fibres following the death of a motoneuron. Whereas this process helps mitigate loss of muscle mass during the latter decades of adult aging, the neuromuscular system has fewer and larger MUs, which have lower quality connections between the axon terminal and innervated muscle fibres. Whether this process of MU death and degradation can be attenuated with habitual physical activity has been a challenging question of great interest. This review focuses on age-related alterations of the human neuromuscular system, with an emphasis on the MU, and presents findings on the potential protective effects of lifelong physical activity. Although there is some discrepancy across studies of masters athletes, if one considers all experimental limitations as well as the available literature in animals, there is compelling evidence of a protective effect of chronic physical training on human MUs. Our tenet is that high-levels of physical activity can mitigate the natural trajectory of loss of quantity and quality of MUs in old age.
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Affiliation(s)
- Matti D Allen
- Department of Physical Medicine and Rehabilitation, School of Medicine, Faculty of Health Sciences, Queen's University, Kingston, ON K7L 4X3, Canada; School of Kinesiology and Health Studies, Faculty of Arts and Sciences, Queen's University, Kingston, ON K7L 4X3, Canada
| | - Brian H Dalton
- School of Health and Exercise Science, University of British Columbia, Kelowna, BC V1V 1V7, Canada
| | - Kevin J Gilmore
- Department of Surgery, Faculty of Medicine, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Chris J McNeil
- School of Health and Exercise Science, University of British Columbia, Kelowna, BC V1V 1V7, Canada
| | - Timothy J Doherty
- Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON, Canada; Department of Physical Medicine and Rehabilitation, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON, Canada
| | - Charles L Rice
- School of Kinesiology, The University of Western Ontario, London, ON, Canada; Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON, Canada.
| | - Geoffrey A Power
- Department of Human Health and Nutritional Sciences, College of Biological Sciences, University of Guelph, Guelph, ON N1G 2W1, Canada
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48
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Soendenbroe C, Andersen JL, Mackey AL. Muscle-nerve communication and the molecular assessment of human skeletal muscle denervation with aging. Am J Physiol Cell Physiol 2021; 321:C317-C329. [PMID: 34161153 DOI: 10.1152/ajpcell.00174.2021] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Muscle fiber denervation is a major contributor to the decline in physical function observed with aging. Denervation can occur through breakdown of the neuromuscular junctions (NMJ) itself, affecting only that particular fiber, or through the death of a motor neuron, which can lead to a loss of all the muscle fibers in that motor unit. In this review, we discuss the muscle-nerve relationship, where signaling from both the motor neuron and the muscle fiber is required for maximal preservation of neuromuscular function in old age. Physical activity is likely to be the most important single factor that can contribute to this preservation. Furthermore, we propose that inactivity is not an innocent bystander, but plays an active role in denervation through the production of signals hostile to neuron survival. Investigating denervation in human muscle tissue samples is challenging due to the shared protein profile of regenerating and denervated muscle fibers. In this review, we provide a detailed overview of the key traits observed in immunohistochemical preparations of muscle biopsies from healthy, young, and elderly individuals. Overall, a combination of assessing tissue samples, circulating biomarkers, and electrophysiological assessments in humans will prove fruitful in the quest to gain more understanding of denervation of skeletal muscle. In addition, cell culture models represent a valuable tool in the search for key signaling factors exchanged between muscle and nerve, and which exercise has the capacity to alter.
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Affiliation(s)
- Casper Soendenbroe
- Department of Orthopedic Surgery, Institute of Sports Medicine Copenhagen, Copenhagen University Hospital - Bispebjerg and Frederiksberg, Copenhagen, Denmark.,Xlab, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Medicine, Center for Healthy Aging, University of Copenhagen, Copenhagen, Denmark
| | - Jesper L Andersen
- Department of Orthopedic Surgery, Institute of Sports Medicine Copenhagen, Copenhagen University Hospital - Bispebjerg and Frederiksberg, Copenhagen, Denmark.,Department of Clinical Medicine, Center for Healthy Aging, University of Copenhagen, Copenhagen, Denmark
| | - Abigail L Mackey
- Department of Orthopedic Surgery, Institute of Sports Medicine Copenhagen, Copenhagen University Hospital - Bispebjerg and Frederiksberg, Copenhagen, Denmark.,Xlab, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Medicine, Center for Healthy Aging, University of Copenhagen, Copenhagen, Denmark
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49
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McDermott MM, Dayanidhi S, Kosmac K, Saini S, Slysz J, Leeuwenburgh C, Hartnell L, Sufit R, Ferrucci L. Walking Exercise Therapy Effects on Lower Extremity Skeletal Muscle in Peripheral Artery Disease. Circ Res 2021; 128:1851-1867. [PMID: 34110902 DOI: 10.1161/circresaha.121.318242] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Walking exercise is the most effective noninvasive therapy that improves walking ability in peripheral artery disease (PAD). Biologic mechanisms by which exercise improves walking in PAD are unclear. This review summarizes evidence regarding effects of walking exercise on lower extremity skeletal muscle in PAD. In older people without PAD, aerobic exercise improves mitochondrial activity, muscle mass, capillary density, and insulin sensitivity in skeletal muscle. However, walking exercise increases lower extremity ischemia in people with PAD, and therefore, mechanisms by which this exercise improves walking may differ between people with and without PAD. Compared with people without PAD, gastrocnemius muscle in people with PAD has greater mitochondrial impairment, increased reactive oxygen species, and increased fibrosis. In multiple small trials, walking exercise therapy did not consistently improve mitochondrial activity in people with PAD. In one 12-week randomized trial of people with PAD randomized to supervised exercise or control, supervised treadmill exercise increased treadmill walking time from 9.3 to 15.1 minutes, but simultaneously increased the proportion of angular muscle fibers, consistent with muscle denervation (from 7.6% to 15.6%), while angular myofibers did not change in the control group (from 9.1% to 9.1%). These findings suggest an adaptive response to exercise in PAD that includes denervation and reinnervation, an adaptive process observed in skeletal muscle of people without PAD during aging. Small studies have not shown significant effects of exercise on increased capillary density in lower extremity skeletal muscle of participants with PAD, and there are no data showing that exercise improves microcirculatory delivery of oxygen and nutrients in patients with PAD. However, the effects of supervised exercise on increased plasma nitrite abundance after a treadmill walking test in people with PAD may be associated with improved lower extremity skeletal muscle perfusion and may contribute to improved walking performance in response to exercise in people with PAD. Randomized trials with serial, comprehensive measures of muscle biology, and physiology are needed to clarify mechanisms by which walking exercise interventions improve mobility in PAD.
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Affiliation(s)
- Mary M McDermott
- Department of Medicine and Preventive Medicine (M.M.M., J.S.), Northwestern University Feinberg School of Medicine
| | - Sudarshan Dayanidhi
- Shirley Ryan Ability Laboratory (S.D.), Northwestern University Feinberg School of Medicine
| | - Kate Kosmac
- Center for Muscle Biology, University of Kentucky (K.K.)
| | - Sunil Saini
- Jawaharlal Nehru University, School of Biotechnology, New Delhi, India (S.S.)
| | - Joshua Slysz
- Department of Medicine and Preventive Medicine (M.M.M., J.S.), Northwestern University Feinberg School of Medicine
| | | | - Lisa Hartnell
- Division of Intramural Research, National Institute on Aging (L.H., L.F.)
| | - Robert Sufit
- Department of Neurology (R.S.), Northwestern University Feinberg School of Medicine
| | - Luigi Ferrucci
- Division of Intramural Research, National Institute on Aging (L.H., L.F.)
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50
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Dobrowolny G, Barbiera A, Sica G, Scicchitano BM. Age-Related Alterations at Neuromuscular Junction: Role of Oxidative Stress and Epigenetic Modifications. Cells 2021; 10:1307. [PMID: 34074012 PMCID: PMC8225025 DOI: 10.3390/cells10061307] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 05/19/2021] [Accepted: 05/22/2021] [Indexed: 12/11/2022] Open
Abstract
With advancing aging, a decline in physical abilities occurs, leading to reduced mobility and loss of independence. Although many factors contribute to the physio-pathological effects of aging, an important event seems to be related to the compromised integrity of the neuromuscular system, which connects the brain and skeletal muscles via motoneurons and the neuromuscular junctions (NMJs). NMJs undergo severe functional, morphological, and molecular alterations during aging and ultimately degenerate. The effect of this decline is an inexorable decrease in skeletal muscle mass and strength, a condition generally known as sarcopenia. Moreover, several studies have highlighted how the age-related alteration of reactive oxygen species (ROS) homeostasis can contribute to changes in the neuromuscular junction morphology and stability, leading to the reduction in fiber number and innervation. Increasing evidence supports the involvement of epigenetic modifications in age-dependent alterations of the NMJ. In particular, DNA methylation, histone modifications, and miRNA-dependent gene expression represent the major epigenetic mechanisms that play a crucial role in NMJ remodeling. It is established that environmental and lifestyle factors, such as physical exercise and nutrition that are susceptible to change during aging, can modulate epigenetic phenomena and attenuate the age-related NMJs changes. This review aims to highlight the recent epigenetic findings related to the NMJ dysregulation during aging and the role of physical activity and nutrition as possible interventions to attenuate or delay the age-related decline in the neuromuscular system.
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Affiliation(s)
- Gabriella Dobrowolny
- Department of Anatomy, Histology, Forensic Medicine and Orthopaedics (DAHFMO)-Unit of Histology and Medical Embryology, Sapienza University of Rome, Laboratory Affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, 00161 Rome, Italy;
| | - Alessandra Barbiera
- Department of Life Sciences and Public Health, Histology and Embryology Unit, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (A.B.); (G.S.)
| | - Gigliola Sica
- Department of Life Sciences and Public Health, Histology and Embryology Unit, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (A.B.); (G.S.)
| | - Bianca Maria Scicchitano
- Department of Life Sciences and Public Health, Histology and Embryology Unit, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (A.B.); (G.S.)
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