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Haug M, Michael M, Ritter P, Kovbasyuk L, Vazakidou ME, Friedrich O. Levosimendan's Effects on Length-Dependent Activation in Murine Fast-Twitch Skeletal Muscle. Int J Mol Sci 2024; 25:6191. [PMID: 38892380 PMCID: PMC11172453 DOI: 10.3390/ijms25116191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 05/29/2024] [Accepted: 05/29/2024] [Indexed: 06/21/2024] Open
Abstract
Levosimendan's calcium sensitizing effects in heart muscle cells are well established; yet, its potential impact on skeletal muscle cells has not been evidently determined. Despite controversial results, levosimendan is still expected to interact with skeletal muscle through off-target sites (further than troponin C). Adding to this debate, we investigated levosimendan's acute impact on fast-twitch skeletal muscle biomechanics in a length-dependent activation study by submersing single muscle fibres in a levosimendan-supplemented solution. We employed our MyoRobot technology to investigate the calcium sensitivity of skinned single muscle fibres alongside their stress-strain response in the presence or absence of levosimendan (100 µM). While control data are in agreement with the theory of length-dependent activation, levosimendan appears to shift the onset of the 'descending limb' of active force generation to longer sarcomere lengths without notably improving myofibrillar calcium sensitivity. Passive stretches in the presence of levosimendan yielded over twice the amount of enlarged restoration stress and Young's modulus in comparison to control single fibres. Both effects have not been described before and may point towards potential off-target sites of levosimendan.
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Affiliation(s)
- Michael Haug
- Institute of Medical Biotechnology, Department of Chemical and Biological Engineering, Friedrich-Alexander-University Erlangen-Nürnberg, Paul-Gordan Str. 3, 91052 Erlangen, Germany; (M.M.); (P.R.); (L.K.); (M.E.V.); (O.F.)
- Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-University Erlangen-Nürnberg, Paul-Gordan-Str. 6, 91052 Erlangen, Germany
| | - Mena Michael
- Institute of Medical Biotechnology, Department of Chemical and Biological Engineering, Friedrich-Alexander-University Erlangen-Nürnberg, Paul-Gordan Str. 3, 91052 Erlangen, Germany; (M.M.); (P.R.); (L.K.); (M.E.V.); (O.F.)
- Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-University Erlangen-Nürnberg, Paul-Gordan-Str. 6, 91052 Erlangen, Germany
| | - Paul Ritter
- Institute of Medical Biotechnology, Department of Chemical and Biological Engineering, Friedrich-Alexander-University Erlangen-Nürnberg, Paul-Gordan Str. 3, 91052 Erlangen, Germany; (M.M.); (P.R.); (L.K.); (M.E.V.); (O.F.)
- Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-University Erlangen-Nürnberg, Paul-Gordan-Str. 6, 91052 Erlangen, Germany
| | - Larisa Kovbasyuk
- Institute of Medical Biotechnology, Department of Chemical and Biological Engineering, Friedrich-Alexander-University Erlangen-Nürnberg, Paul-Gordan Str. 3, 91052 Erlangen, Germany; (M.M.); (P.R.); (L.K.); (M.E.V.); (O.F.)
| | - Maria Eleni Vazakidou
- Institute of Medical Biotechnology, Department of Chemical and Biological Engineering, Friedrich-Alexander-University Erlangen-Nürnberg, Paul-Gordan Str. 3, 91052 Erlangen, Germany; (M.M.); (P.R.); (L.K.); (M.E.V.); (O.F.)
| | - Oliver Friedrich
- Institute of Medical Biotechnology, Department of Chemical and Biological Engineering, Friedrich-Alexander-University Erlangen-Nürnberg, Paul-Gordan Str. 3, 91052 Erlangen, Germany; (M.M.); (P.R.); (L.K.); (M.E.V.); (O.F.)
- Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-University Erlangen-Nürnberg, Paul-Gordan-Str. 6, 91052 Erlangen, Germany
- School of Biomedical Sciences, University of New South Wales, Wallace Wurth Building, 18 High St., Sydney, NSW 2052, Australia
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Fitzgerald LS, Bremner SN, Ward SR, Cho Y, Schenk S. Intrinsic skeletal muscle function and contraction-stimulated glucose uptake do not vary by time-of-day in mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.15.594323. [PMID: 38798320 PMCID: PMC11118484 DOI: 10.1101/2024.05.15.594323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
A growing body of data suggests that skeletal muscle contractile function and glucose metabolism vary by time-of-day, with chronobiological effects on intrinsic skeletal muscle properties being proposed as the underlying mediator. However, no studies have directly investigated intrinsic contractile function or glucose metabolism in skeletal muscle over a 24 h circadian cycle. To address this, we assessed intrinsic contractile function and endurance, as well as contraction-stimulated glucose uptake, in isolated extensor digitorum longus and soleus from female mice at four times-of-day (Zeitgeber Times 1, 7, 13, 19). Significantly, while both muscles demonstrated circadian-related changes in gene expression, intrinsic contractile function, endurance, and contraction-stimulated glucose uptake were not different between the four time points. Overall, these results demonstrate that time-of-day variation in exercise performance and the glycemia-reducing benefits of exercise are not due to chronobiological effects on intrinsic muscle function or contraction-stimulated glucose uptake. Impact statement Ex vivo testing demonstrates that there is no time-of-day variation in the intrinsic contractile properties of skeletal muscle (including no effect on force production or endurance) or contraction-stimulated glucose uptake.
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Shelley SP, James RS, Tallis J. The effects of muscle starting length on work loop power output of isolated mouse soleus and extensor digitorum longus muscle. J Exp Biol 2024; 227:jeb247158. [PMID: 38584504 DOI: 10.1242/jeb.247158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 03/27/2024] [Indexed: 04/09/2024]
Abstract
Force-length relationships derived from isometric activations may not directly apply to muscle force production during dynamic contractions. As such, different muscle starting lengths between isometric and dynamic conditions could be required to achieve maximal force and power. Therefore, this study examined the effects of starting length [±5-10% of length corresponding to maximal twitch force (L0)] on work loop (WL) power output (PO), across a range of cycle frequencies, of the soleus (SOL) and extensor digitorum longus muscle (EDL; N=8-10) isolated from ∼8 week old C57 mice. Furthermore, passive work was examined at a fixed cycle frequency to determine the association of passive work and active net work. Starting length affected maximal WL PO of the SOL and EDL across evaluated cycle frequencies (P<0.030, ηp2>0.494). For the SOL, PO produced at -5% L0 was greater than that at most starting lengths (P<0.015, Cohen's d>0.6), except -10% L0 (P=0.135, d<0.4). However, PO produced at -10% L0 versus L0 did not differ (P=0.138, d=0.35-0.49), indicating -5% L0 is optimal for maximal SOL WL PO. For the EDL, WL PO produced at -10% L0 was lower than that at most starting lengths (P<0.032, d>1.08), except versus -5% L0 (P=0.124, d<0.97). PO produced at other starting lengths did not differ (P>0.163, d<1.04). For the SOL, higher passive work was associated with reduced PO (Spearman's r=0.709, P<0.001), but no relationship was observed between passive work and PO of the EDL (Pearson's r=0.191, r2=0.04, P=0.184). This study suggests that starting length should be optimised for both static and dynamic contractions and confirms that the force-length curve during dynamic contractions is muscle specific.
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Affiliation(s)
- Sharn P Shelley
- Research Centre for Physical Activity, Sport and Exercise Science, Coventry University, Coventry, CV1 5FB, UK
| | - Rob S James
- Faculty of Life Sciences, University of Bradford, Bradford, BD7 1DP, UK
| | - Jason Tallis
- Research Centre for Physical Activity, Sport and Exercise Science, Coventry University, Coventry, CV1 5FB, UK
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Kim Y, Parry HA, Willingham TB, Alspaugh G, Lindberg E, Combs CA, Knutson JR, Bleck CKE, Glancy B. Reorganization of mitochondria-organelle interactions during postnatal development in skeletal muscle. J Physiol 2024; 602:891-912. [PMID: 38429930 PMCID: PMC10939894 DOI: 10.1113/jp285014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 01/16/2024] [Indexed: 03/03/2024] Open
Abstract
Skeletal muscle cellular development requires the integrated assembly of mitochondria and other organelles adjacent to the sarcomere in support of muscle contractile performance. However, it remains unclear how interactions among organelles and with the sarcomere relates to the development of muscle cell function. Here, we combine 3D volume electron microscopy, proteomic analyses, and live cell functional imaging to investigate the postnatal reorganization of mitochondria-organelle interactions in skeletal muscle. We show that while mitochondrial networks are disorganized and loosely associated with the contractile apparatus at birth, contact sites among mitochondria, lipid droplets and the sarcoplasmic reticulum are highly abundant in neonatal muscles. The maturation process is characterized by a transition to highly organized mitochondrial networks wrapped tightly around the muscle sarcomere but also to less frequent interactions with both lipid droplets and the sarcoplasmic reticulum. Concomitantly, expression of proteins involved in mitochondria-organelle membrane contact sites decreases during postnatal development in tandem with a decrease in abundance of proteins associated with sarcomere assembly despite an overall increase in contractile protein abundance. Functionally, parallel measures of mitochondrial membrane potential, NADH redox status, and NADH flux within intact cells revealed that mitochondria in adult skeletal muscle fibres maintain a more activated electron transport chain compared with neonatal muscle mitochondria. These data demonstrate a developmental redesign reflecting a shift from muscle cell assembly and frequent inter-organelle communication toward a muscle fibre with mitochondrial structure, interactions, composition and function specialized to support contractile function. KEY POINTS: Mitochondrial network organization is remodelled during skeletal muscle postnatal development. The mitochondrial outer membrane is in frequent contact with other organelles at birth and transitions to more close associations with the contractile apparatus in mature muscles. Mitochondrial energy metabolism becomes more activated during postnatal development. Understanding the developmental redesign process within skeletal muscle cells may help pinpoint specific areas of deficit in muscles with developmental disorders.
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Affiliation(s)
- Yuho Kim
- National Heart, Lung, and Blood Institute National Institutes of Health, Bethesda, MD 20892, USA
- Department of Physical Therapy and Kinesiology, University of Massachusetts Lowell, MA 01854, USA
| | - Hailey A. Parry
- National Heart, Lung, and Blood Institute National Institutes of Health, Bethesda, MD 20892, USA
| | - T. Bradley Willingham
- National Heart, Lung, and Blood Institute National Institutes of Health, Bethesda, MD 20892, USA
| | - Greg Alspaugh
- National Heart, Lung, and Blood Institute National Institutes of Health, Bethesda, MD 20892, USA
| | - Eric Lindberg
- National Heart, Lung, and Blood Institute National Institutes of Health, Bethesda, MD 20892, USA
| | - Christian A. Combs
- National Heart, Lung, and Blood Institute National Institutes of Health, Bethesda, MD 20892, USA
| | - Jay R. Knutson
- National Heart, Lung, and Blood Institute National Institutes of Health, Bethesda, MD 20892, USA
| | - Christopher K. E. Bleck
- National Heart, Lung, and Blood Institute National Institutes of Health, Bethesda, MD 20892, USA
| | - Brian Glancy
- National Heart, Lung, and Blood Institute National Institutes of Health, Bethesda, MD 20892, USA
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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Sprinchorn AE, Eizenberg N, Barker PJ. Differences and similarities in muscle architecture of fibularis longus and brevis-An observational descriptive cross-sectional and feasibility study. J Orthop Surg Res 2024; 19:105. [PMID: 38303020 PMCID: PMC10832119 DOI: 10.1186/s13018-024-04594-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 01/28/2024] [Indexed: 02/03/2024] Open
Abstract
BACKGROUND The fibularis longus (FL) muscle is larger in volume than fibularis brevis (FB) and is therefore claimed to be the stronger evertor of the two. Clinical observation of FL and FB tendon rupture show that injury to the FB has a serious negative effect on hindfoot eversion. This implies that the FB is the stronger and more important evertor. The strength of a muscle is not purely based on its volume, and the observed discrepancy between the FB and FL may be due to differences in muscle architecture. This study compares the muscle architecture of FL with FB. METHODS Sixteen legs from eight formaldehyde-fixed human specimens, mean age 83 (range 72-89) years, were dissected. The volume, fibre lengths and fibre pennation angles for both muscles were measured and the physiological cross-sectional area (PCSA) was calculated. RESULTS The FL was always larger than the FB, with an individual difference in volume that varied from 1.4 to 4.6 times larger with a mean difference of 17 ml (95% CI 14-20; p < 0.001). Mean fibre lengths were 9 mm (95% CI 2-16; p = 0.015) longer in FL than in FB. The mean pennation angle was 9.6 degrees in FL and 8.8 degrees in FB, this difference was not significant (p = 0.32). The mean PCSA for FL was 3 cm2 (95% CI 2-4) larger than for FB (p < 0.001). CONCLUSIONS With our sample set, the hypothesis that the muscle architecture can explain the clinical discrepancy between the FL and FB, was not supported. The difference in hindfoot eversion might instead depend on the different moment arms of FL and FB and the effect forefoot abduction has on hindfoot eversion.
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O’Brien JG, Willis AB, Long AM, Kwon J, Lee G, Li FW, Page PG, Vo AH, Hadhazy M, Spencer MJ, Crosbie RH, Demonbreun AR, McNally EM. The super-healing MRL strain promotes muscle growth in muscular dystrophy through a regenerative extracellular matrix. JCI Insight 2024; 9:e173246. [PMID: 38175727 PMCID: PMC11143963 DOI: 10.1172/jci.insight.173246] [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: 06/21/2023] [Accepted: 12/21/2023] [Indexed: 01/05/2024] Open
Abstract
The Murphy Roths Large (MRL) mouse strain has "super-healing" properties that enhance recovery from injury. In mice, the DBA/2J strain intensifies many aspects of muscular dystrophy, so we evaluated the ability of the MRL strain to suppress muscular dystrophy in the Sgcg-null mouse model of limb girdle muscular dystrophy. A comparative analysis of Sgcg-null mice in the DBA/2J versus MRL strains showed greater myofiber regeneration, with reduced structural degradation of muscle in the MRL strain. Transcriptomic profiling of dystrophic muscle indicated strain-dependent expression of extracellular matrix (ECM) and TGF-β signaling genes. To investigate the MRL ECM, cellular components were removed from dystrophic muscle sections to generate decellularized myoscaffolds. Decellularized myoscaffolds from dystrophic mice in the protective MRL strain had significantly less deposition of collagen and matrix-bound TGF-β1 and TGF-β3 throughout the matrix. Dystrophic myoscaffolds from the MRL background, but not the DBA/2J background, were enriched in myokines like IGF-1 and IL-6. C2C12 myoblasts seeded onto decellularized matrices from Sgcg-/- MRL and Sgcg-/- DBA/2J muscles showed the MRL background induced greater myoblast differentiation compared with dystrophic DBA/2J myoscaffolds. Thus, the MRL background imparts its effect through a highly regenerative ECM, which is active even in muscular dystrophy.
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Affiliation(s)
- Joseph G. O’Brien
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Alexander B. Willis
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Ashlee M. Long
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Jason Kwon
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - GaHyun Lee
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Frank W. Li
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Patrick G.T. Page
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Andy H. Vo
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Michele Hadhazy
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Melissa J. Spencer
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, California, USA
| | - Rachelle H. Crosbie
- Department of Integrative Biology and Physiology, Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, California, USA
| | - Alexis R. Demonbreun
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Elizabeth M. McNally
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
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Kucewicz STC, Borkowski M, Church JE, van der Poel C. Measurement of Murine Neuromuscular Function Using the In Situ Preparation. Methods Mol Biol 2024; 2746:147-154. [PMID: 38070087 DOI: 10.1007/978-1-0716-3585-8_12] [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] [Indexed: 12/18/2023]
Abstract
The presence and progression of a neuromuscular pathology can impact on the contractile force production of a muscle. Hence, measurements of force production can be an important tool for the evaluation of disease progression. In this chapter, we describe how to perform in situ function testing on the tibialis anterior muscle using a murine model. Performing neuromuscular in situ function testing allows force measurements to be recorded in a physiologically relevant environment.
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Affiliation(s)
- S T C Kucewicz
- Department of Microbiology, Anatomy, Physiology & Pharmacology, School of Agriculture, Biomedicine & Environment, La Trobe University, Melbourne, VIC, Australia
| | | | | | - C van der Poel
- Department of Microbiology, Anatomy, Physiology & Pharmacology, School of Agriculture, Biomedicine & Environment, La Trobe University, Melbourne, VIC, Australia.
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Gushchina LV, Bradley AJ, Vetter TA, Lay JW, Rohan NL, Frair EC, Wein N, Flanigan KM. Persistence of exon 2 skipping and dystrophin expression at 18 months after U7snRNA-mediated therapy in the Dup2 mouse model. Mol Ther Methods Clin Dev 2023; 31:101144. [PMID: 38027058 PMCID: PMC10679948 DOI: 10.1016/j.omtm.2023.101144] [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: 08/22/2023] [Accepted: 10/24/2023] [Indexed: 12/01/2023]
Abstract
Duchenne muscular dystrophy (DMD) is a progressive X-linked disease caused by mutations in the DMD gene that prevent the expression of a functional dystrophin protein. Exon duplications represent 6%-11% of mutations, and duplications of exon 2 (Dup2) are the most common (∼11%) of duplication mutations. An exon-skipping strategy for Dup2 mutations presents a large therapeutic window. Skipping one exon copy results in full-length dystrophin expression, whereas skipping of both copies (Del2) activates an internal ribosomal entry site (IRES) in exon 5, inducing the expression of a highly functional truncated dystrophin isoform. We have previously confirmed the therapeutic efficacy of AAV9.U7snRNA-mediated skipping in the Dup2 mouse model and showed the absence of off-target splicing effects and lack of toxicity in mice and nonhuman primates. Here, we report long-term dystrophin expression data following the treatment of 3-month-old Dup2 mice with the scAAV9.U7.ACCA vector. Significant exon 2 skipping and robust dystrophin expression in the muscles and hearts of treated mice persist at 18 months after treatment, along with the partial rescue of muscle function. These data extend our previous findings and show that scAAV9.U7.ACCA provides long-term protection by restoring the disrupted dystrophin reading frame in the context of exon 2 duplications.
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Affiliation(s)
- Liubov V. Gushchina
- The Center for Gene Therapy, Nationwide Children’s Hospital and The Ohio State University, Columbus, OH, USA
- Department of Pediatrics, The Ohio State University, Columbus, OH, USA
| | - Adrienne J. Bradley
- The Center for Gene Therapy, Nationwide Children’s Hospital and The Ohio State University, Columbus, OH, USA
| | - Tatyana A. Vetter
- The Center for Gene Therapy, Nationwide Children’s Hospital and The Ohio State University, Columbus, OH, USA
- Department of Pediatrics, The Ohio State University, Columbus, OH, USA
| | - Jacob W. Lay
- The Center for Gene Therapy, Nationwide Children’s Hospital and The Ohio State University, Columbus, OH, USA
| | - Natalie L. Rohan
- The Center for Gene Therapy, Nationwide Children’s Hospital and The Ohio State University, Columbus, OH, USA
| | - Emma C. Frair
- The Center for Gene Therapy, Nationwide Children’s Hospital and The Ohio State University, Columbus, OH, USA
| | - Nicolas Wein
- The Center for Gene Therapy, Nationwide Children’s Hospital and The Ohio State University, Columbus, OH, USA
- Department of Pediatrics, The Ohio State University, Columbus, OH, USA
| | - Kevin M. Flanigan
- The Center for Gene Therapy, Nationwide Children’s Hospital and The Ohio State University, Columbus, OH, USA
- Department of Pediatrics, The Ohio State University, Columbus, OH, USA
- Department of Neurology, The Ohio State University, Columbus, OH, USA
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Sayed RKA, Hibbert JE, Jorgenson KW, Hornberger TA. The Structural Adaptations That Mediate Disuse-Induced Atrophy of Skeletal Muscle. Cells 2023; 12:2811. [PMID: 38132132 PMCID: PMC10741885 DOI: 10.3390/cells12242811] [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: 11/11/2023] [Revised: 12/07/2023] [Accepted: 12/09/2023] [Indexed: 12/23/2023] Open
Abstract
The maintenance of skeletal muscle mass plays a fundamental role in health and issues associated with quality of life. Mechanical signals are one of the most potent regulators of muscle mass, with a decrease in mechanical loading leading to a decrease in muscle mass. This concept has been supported by a plethora of human- and animal-based studies over the past 100 years and has resulted in the commonly used term of 'disuse atrophy'. These same studies have also provided a great deal of insight into the structural adaptations that mediate disuse-induced atrophy. For instance, disuse results in radial atrophy of fascicles, and this is driven, at least in part, by radial atrophy of the muscle fibers. However, the ultrastructural adaptations that mediate these changes remain far from defined. Indeed, even the most basic questions, such as whether the radial atrophy of muscle fibers is driven by the radial atrophy of myofibrils and/or myofibril hypoplasia, have yet to be answered. In this review, we thoroughly summarize what is known about the macroscopic, microscopic, and ultrastructural adaptations that mediated disuse-induced atrophy and highlight some of the major gaps in knowledge that need to be filled.
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Affiliation(s)
- Ramy K. A. Sayed
- Department of Comparative Biosciences, University of Wisconsin—Madison, Madison, WI 53706, USA; (R.K.A.S.); (J.E.H.); (K.W.J.)
- School of Veterinary Medicine, University of Wisconsin—Madison, Madison, WI 53706, USA
- Department of Anatomy and Embryology, Faculty of Veterinary Medicine, Sohag University, Sohag 82524, Egypt
| | - Jamie E. Hibbert
- Department of Comparative Biosciences, University of Wisconsin—Madison, Madison, WI 53706, USA; (R.K.A.S.); (J.E.H.); (K.W.J.)
- School of Veterinary Medicine, University of Wisconsin—Madison, Madison, WI 53706, USA
| | - Kent W. Jorgenson
- Department of Comparative Biosciences, University of Wisconsin—Madison, Madison, WI 53706, USA; (R.K.A.S.); (J.E.H.); (K.W.J.)
- School of Veterinary Medicine, University of Wisconsin—Madison, Madison, WI 53706, USA
| | - Troy A. Hornberger
- Department of Comparative Biosciences, University of Wisconsin—Madison, Madison, WI 53706, USA; (R.K.A.S.); (J.E.H.); (K.W.J.)
- School of Veterinary Medicine, University of Wisconsin—Madison, Madison, WI 53706, USA
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Wellette-Hunsucker AG, Leszczynski EC, Visker JR, Pritchard A, Mcpeek AC, Quinn MA, Wen Y, Albathi F, Slade JM, Ferguson DP. The Effect of Downhill Running on Quadriceps Muscle in Growth-Restricted Mice. Med Sci Sports Exerc 2023; 55:2160-2169. [PMID: 37486763 PMCID: PMC10805954 DOI: 10.1249/mss.0000000000003259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/25/2023]
Abstract
INTRODUCTION Growth restriction (GR) reduces ribosome abundance and skeletal muscle mass in mice. A reduction in skeletal muscle mass increases the risk of frailty and is associated with high morbidity and mortality rates. As eccentric type exercise increases muscle mass, this investigation aimed to determine if eccentric loading of skeletal muscle via downhill running (DHR) increased muscle mass in GR mice. METHODS Mice were growth-restricted either gestational undernutrition (GUN, n = 8 litters), postnatal undernutrition (PUN, n = 8 litters), or were not restricted (CON, n = 8 litters) via a validated cross-fostering nutritive model. On postnatal day (PN) 21, all mice were weaned to a healthy diet, isolating the period of GR to early life as seen in humans. At PN45, mice were assigned to either a DHR (CON, n = 4 litters; GUN, n = 4 litters; PUN, n = 4 litters) or sedentary (SED: CON, n = 4 litters; GUN, n = 4 litters; PUN, n = 4 litters) group. Downhill running (16% decline: 18 m·min -1 ) was performed in 30-min bouts, three times per week, for 12 wk on a rodent treadmill. At PN129, the quadriceps femoris was dissected and evaluated for mass, myofiber size and type, and molecular markers of growth. RESULTS Following training, CON-DHR mice having larger cells than CON-SED, GUN-SED, PUN-SED, and PUN-DHR mice ( P < 0.05). The PUN group (as compared with CON) had reduced body mass ( P < 0.001), upstream binding factor abundance ( P = 0.012), phosphor-mTOR ( P < 0.001), and quadriceps mass ( P = 0.02). The GUN and PUN groups had increased MuRF1 abundance ( P < 0.001) compared with CON ( P < 0.001). CONCLUSIONS The blunted response to training suggests GR mice may have anabolic resistance when exposed to eccentric type exercise.
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Affiliation(s)
- Austin G. Wellette-Hunsucker
- Department of Kinesiology, Michigan State University, East Lansing, MI
- Deparment of Physiology, College of Medicine, University of Kentucky, Lexington, KY
- Center for Muscle Biology, University of Kentucky, Lexington, KY
| | | | - Joseph R. Visker
- Department of Kinesiology, Michigan State University, East Lansing, MI
- The Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT
| | - Abby Pritchard
- Department of Animal Science, Michigan State University, East Lansing, MI
- Regulatory and Nutritional Compliance, Mars Petcare, Franklin, TN
| | - Ashley C. Mcpeek
- Department of Kinesiology, Michigan State University, East Lansing, MI
| | - Melissa A. Quinn
- Department of Kinesiology, Michigan State University, East Lansing, MI
| | - Yuan Wen
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, KY
- Center for Muscle Biology, University of Kentucky, Lexington, KY
| | - Fatmah Albathi
- Department of Pharmacology and Nutritional Sciences, College of Medicine, University of Kentucky, Lexington, KY
| | - Jill M. Slade
- Department of Radiology, Michigan State University, East Lansing, MI
| | - David P. Ferguson
- Department of Kinesiology, Michigan State University, East Lansing, MI
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11
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Lea TA, Panizza PM, Arthur PG, Bakker AJ, Pinniger GJ. Hypochlorous acid exposure impairs skeletal muscle function and Ca 2+ signalling: implications for Duchenne muscular dystrophy pathology. J Physiol 2023; 601:5257-5275. [PMID: 37864413 DOI: 10.1113/jp285263] [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: 07/11/2023] [Accepted: 10/09/2023] [Indexed: 10/22/2023] Open
Abstract
Duchenne muscular dystrophy (DMD) is a fatal X-linked disease characterised by severe muscle wasting. The mechanisms underlying the DMD pathology likely involve the interaction between inflammation, oxidative stress and impaired Ca2+ signalling. Hypochlorous acid (HOCl) is a highly reactive oxidant produced endogenously via myeloperoxidase; an enzyme secreted by neutrophils that is significantly elevated in dystrophic muscle. Oxidation of Ca2+ -handling proteins by HOCl may impair Ca2+ signalling. This study aimed to determine the effects of HOCl on skeletal muscle function and its potential contribution to the dystrophic pathology. Extensor digitorum longus (EDL), soleus and interosseous muscles were surgically isolated from anaesthetised C57 (wild-type) and mdx (dystrophic) mice for measurement of ex vivo force production and intracellular Ca2+ concentration. In whole EDL muscle, HOCl (200 μM) significantly decreased maximal force and increased resting muscle tension which was only partially reversible by dithiothreitol. The effects of HOCl (200 μM) on maximal force in slow-twitch soleus were lower than found in the fast-twitch EDL muscle. In single interosseous myofibres, HOCl (10 μM) significantly increased resting intracellular Ca2+ concentration and decreased Ca2+ transient amplitude. These effects of HOCl were reduced by the application of tetracaine, Gd3+ or streptomycin, implicating involvement of ryanodine receptors and transient receptor potential channels. These results demonstrate the potent effects of HOCl on skeletal muscle function potentially mediated by HOCl-induced oxidation to Ca2+ signalling proteins. Hence, HOCl may provide a link between chronic inflammation, oxidative stress and impaired Ca2+ handling that is characteristic of DMD and presents a potential therapeutic target for DMD. KEY POINTS: Duchenne muscular dystrophy is a fatal genetic disease with pathological mechanisms which involve the complex interaction of chronic inflammation, increased reactive oxygen species production and increased cytosolic Ca2+ concentrations. Hypochlorous acid can be endogenously produced by neutrophils via the enzyme myeloperoxidase. Both neutrophil and myeloperoxidase activity are increased in dystrophic mice. This study found that hypochlorous acid decreased muscle force production and increased cytosolic Ca2+ concentrations in isolated muscles from wild-type and dystrophic mice at relatively low concentrations of hypochlorous acid. These results indicate that hypochlorous acid may be key in the Duchenne muscular dystrophy disease pathology and may provide a unifying link between the chronic inflammation, increased reactive oxygen species production and increased cytosolic Ca2+ concentrations observed in Duchenne muscular dystrophy. Hypochlorous acid production may be a potential target for therapeutic treatments of Duchenne muscular dystrophy.
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Affiliation(s)
- Thomas A Lea
- School of Human Sciences, University of Western Australia, Perth, Western Australia, Australia
| | - Peter M Panizza
- School of Human Sciences, University of Western Australia, Perth, Western Australia, Australia
| | - Peter G Arthur
- School of Molecular Sciences, University of Western Australia, Perth, Western Australia, Australia
| | - Anthony J Bakker
- School of Human Sciences, University of Western Australia, Perth, Western Australia, Australia
| | - Gavin J Pinniger
- School of Human Sciences, University of Western Australia, Perth, Western Australia, Australia
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12
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Nishiumi D, Yamaguchi S, Kurokawa T, Wakamiya K, Hirose N. Force-Velocity Profiling During the Braking Phase of Countermovement Jump: Relationship to Eccentric Strength and Validity of the 2-Point Method. J Strength Cond Res 2023; 37:2141-2148. [PMID: 37883394 DOI: 10.1519/jsc.0000000000004544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2023]
Abstract
ABSTRACT Nishiumi, D, Yamaguchi, S, Kurokawa, T, Wakamiya, K, and Hirose, N. Force-velocity profiling during the braking phase of countermovement jump: Relationship to eccentric strength and validity of the 2-point method. J Strength Cond Res 37(11): 2141-2148, 2023-The aims of this study were threefold: to investigate the force-velocity profile during the braking phase (bFVP) of the countermovement jump (CMJ) and its relationship with other performance indicators, and whether it could be measured using the two-point method. Sixteen trained men performed 6 different loaded CMJs (0%, 32 kg, 60, 80, 100, and 120% body mass), and eccentric strength measurements were determined. Scatter plots were created using the mean force and velocity during the braking phase of each loaded CMJ. The corrected Akaike's information criterion (AICc) was calculated by fitting linear, quadratic, and cubic regression equations to the bFVP and compared using the 1-way analysis of variance and Bonferroni's post hoc tests. A correlation analysis was performed between the bFVP and other performance indicators. A bias assessment was performed to validate the 2-point method of the bFVP. The significance level was set at p < 0.05. The AICc in the linear regression equation was significantly lower (p < 0.05) than those in the other regression equations. Significant correlations were found between the slope and theoretical maximum force of the bFVP obtained from the linear regression equation and eccentric 1 repetition maximum. The acceptable condition for bias was met by 0-120%. The bFVP is likely to have a linear relationship and can be associated with eccentric strength. Furthermore, the 2-point method in bFVP has validity.
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Affiliation(s)
- Daichi Nishiumi
- Graduate School of Sport Sciences, Waseda University, Saitama, Japan
| | - Shota Yamaguchi
- Institute of Physical Education, Keio University, Kanagawa, Japan; and
| | - Takanori Kurokawa
- Graduate School of Sport Sciences, Waseda University, Saitama, Japan
| | - Kazuki Wakamiya
- Graduate School of Sport Sciences, Waseda University, Saitama, Japan
| | - Norikazu Hirose
- Faculty of Sport Sciences, Waseda University, Saitama, Japan
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13
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Prabakaran AD, McFarland K, Miz K, Durumutla HB, Piczer K, El Abdellaoui Soussi F, Latimer H, Werbrich C, Blair NS, Millay DP, Prideaux B, Finck BN, Quattrocelli M. Glucocorticoid intermittence coordinates rescue of energy and mass in aging-related sarcopenia through the myocyte-autonomous PGC1alpha-Lipin1 transactivation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.16.562573. [PMID: 37905062 PMCID: PMC10614926 DOI: 10.1101/2023.10.16.562573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Sarcopenia burdens the elderly population through loss of muscle energy and mass, yet treatments to functionally rescue both parameters are missing. The glucocorticoid prednisone remodels muscle metabolism based on frequency of intake, but its mechanisms in sarcopenia are unknown. We found that once-weekly intermittent prednisone rescued muscle quality in aged 24-month-old mice to levels comparable to young 4-month-old mice. We discovered an age- and sex-independent glucocorticoid receptor transactivation program in muscle encompassing PGC1alpha and its co-factor Lipin1. Treatment coordinately improved mitochondrial abundance through isoform 1 and muscle mass through isoform 4 of the myocyte-specific PGC1alpha, which was required for the treatment-driven increase in carbon shuttling from glucose oxidation to amino acid biogenesis. We also probed the myocyte-specific Lipin1 as non-redundant factor coaxing PGC1alpha upregulation to the stimulation of both oxidative and anabolic capacities. Our study unveils an aging-resistant druggable program in myocytes to coordinately rescue energy and mass in sarcopenia.
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Affiliation(s)
- Ashok Daniel Prabakaran
- Molecular Cardiovascular Biology, Heart Institute, Cincinnati Children’s Hospital Medical Center and Dept. Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Kevin McFarland
- Molecular Cardiovascular Biology, Heart Institute, Cincinnati Children’s Hospital Medical Center and Dept. Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Karen Miz
- Molecular Cardiovascular Biology, Heart Institute, Cincinnati Children’s Hospital Medical Center and Dept. Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Hima Bindu Durumutla
- Molecular Cardiovascular Biology, Heart Institute, Cincinnati Children’s Hospital Medical Center and Dept. Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Kevin Piczer
- Molecular Cardiovascular Biology, Heart Institute, Cincinnati Children’s Hospital Medical Center and Dept. Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Fadoua El Abdellaoui Soussi
- Molecular Cardiovascular Biology, Heart Institute, Cincinnati Children’s Hospital Medical Center and Dept. Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Hannah Latimer
- Molecular Cardiovascular Biology, Heart Institute, Cincinnati Children’s Hospital Medical Center and Dept. Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Cole Werbrich
- Molecular Cardiovascular Biology, Heart Institute, Cincinnati Children’s Hospital Medical Center and Dept. Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - N. Scott Blair
- Molecular Cardiovascular Biology, Heart Institute, Cincinnati Children’s Hospital Medical Center and Dept. Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Douglas P Millay
- Molecular Cardiovascular Biology, Heart Institute, Cincinnati Children’s Hospital Medical Center and Dept. Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Brendan Prideaux
- Department of Neuroscience, Cell Biology, and Anatomy, University of Texas Medical Branch (UTMB), Galveston, TX, USA
| | - Brian N Finck
- Department of Medicine, Center for Human Nutrition, Washington University in St Louis, MO, USA
| | - Mattia Quattrocelli
- Molecular Cardiovascular Biology, Heart Institute, Cincinnati Children’s Hospital Medical Center and Dept. Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
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14
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Lindqvist J, Granzier H. Pharmacological Inhibition of Myostatin in a Mouse Model of Typical Nemaline Myopathy Increases Muscle Size and Force. Int J Mol Sci 2023; 24:15124. [PMID: 37894805 PMCID: PMC10606666 DOI: 10.3390/ijms242015124] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 09/27/2023] [Accepted: 10/03/2023] [Indexed: 10/29/2023] Open
Abstract
Nemaline myopathy is one of the most common non-dystrophic congenital myopathies. Individuals affected by this condition experience muscle weakness and muscle smallness, often requiring supportive measures like wheelchairs or respiratory support. A significant proportion of patients, approximately one-third, exhibit compound heterozygous nebulin mutations, which usually give rise to the typical form of the disease. Currently, there are no approved treatments available for nemaline myopathy. Our research explored the modulation of myostatin, a negative regulator of muscle mass, in combating the muscle smallness associated with the disease. To investigate the effect of myostatin inhibition, we employed a mouse model with compound heterozygous nebulin mutations that mimic the typical form of the disease. The mice were treated with mRK35, a myostatin antibody, through weekly intraperitoneal injections of 10 mg/kg mRK35, commencing at two weeks of age and continuing until the mice reached four months of age. The treatment resulted in an increase in body weight and an approximate 20% muscle weight gain across most skeletal muscles, without affecting the heart. The minimum Feret diameter of type IIA and IIB fibers exhibited an increase in compound heterozygous mice, while only type IIB fibers demonstrated an increase in wild-type mice. In vitro mechanical experiments conducted on intact extensor digitorum longus muscle revealed that mRK35 augmented the physiological cross-sectional area of muscle fibers and enhanced absolute tetanic force in both wild-type and compound heterozygous mice. Furthermore, mRK35 administration improved grip strength in treated mice. Collectively, these findings indicate that inhibiting myostatin can mitigate the muscle deficits in nebulin-based typical nemaline myopathy, potentially serving as a much-needed therapeutic option.
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Affiliation(s)
| | - Henk Granzier
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85724, USA;
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15
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Guzman SD, Abu-Mahfouz A, Davis CS, Ruiz LP, Macpherson PC, Brooks SV. Decoding muscle-resident Schwann cell dynamics during neuromuscular junction remodeling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.06.561193. [PMID: 38370853 PMCID: PMC10871306 DOI: 10.1101/2023.10.06.561193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Understanding neuromuscular junction (NMJ) repair mechanisms is essential for addressing degenerative neuromuscular conditions. Here, we focus on the role of muscle-resident Schwann cells in NMJ reinnervation. In young Sod1-/- mice, a model of progressive NMJ degeneration, we identified a clear NMJ 'regenerative window' that allowed us to define regulators of reinnervation and crossing Sod1-/- mice with S100GFP-tg mice permitted visualization and analysis of Schwann cells. High-resolution imaging and single-cell RNA sequencing provide a detailed analysis of Schwann cell number, morphology, and transcriptome revealing multiple subtypes, including a previously unrecognized terminal Schwann cell (tSC) population expressing a synapse promoting signature. We also discovered a novel SPP1-driven cellular interaction between myelin Schwann cells and tSCs and show that it promotes tSC proliferation and reinnervation following nerve injury in wild type mice. Our findings offer important insights into molecular regulators critical in NMJ reinnervation that are mediated through tSCs to maintain NMJ function.
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Affiliation(s)
- Steve D Guzman
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Ahmad Abu-Mahfouz
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Carol S Davis
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Lloyd P Ruiz
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Peter C Macpherson
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Susan V Brooks
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
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16
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Pizza FX, Buckley KH. Regenerating Myofibers after an Acute Muscle Injury: What Do We Really Know about Them? Int J Mol Sci 2023; 24:12545. [PMID: 37628725 PMCID: PMC10454182 DOI: 10.3390/ijms241612545] [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: 07/12/2023] [Revised: 08/02/2023] [Accepted: 08/04/2023] [Indexed: 08/27/2023] Open
Abstract
Injury to skeletal muscle through trauma, physical activity, or disease initiates a process called muscle regeneration. When injured myofibers undergo necrosis, muscle regeneration gives rise to myofibers that have myonuclei in a central position, which contrasts the normal, peripheral position of myonuclei. Myofibers with central myonuclei are called regenerating myofibers and are the hallmark feature of muscle regeneration. An important and underappreciated aspect of muscle regeneration is the maturation of regenerating myofibers into a normal sized myofiber with peripheral myonuclei. Strikingly, very little is known about processes that govern regenerating myofiber maturation after muscle injury. As knowledge of myofiber formation and maturation during embryonic, fetal, and postnatal development has served as a foundation for understanding muscle regeneration, this narrative review discusses similarities and differences in myofiber maturation during muscle development and regeneration. Specifically, we compare and contrast myonuclear positioning, myonuclear accretion, myofiber hypertrophy, and myofiber morphology during muscle development and regeneration. We also discuss regenerating myofibers in the context of different types of myofiber necrosis (complete and segmental) after muscle trauma and injurious contractions. The overall goal of the review is to provide a framework for identifying cellular and molecular processes of myofiber maturation that are unique to muscle regeneration.
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Affiliation(s)
- Francis X. Pizza
- Department of Exercise and Rehabilitation Sciences, University of Toledo, Toledo, OH 43606, USA
| | - Kole H. Buckley
- Division of Gastroenterology and Hepatology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA;
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17
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Nishiumi D, Nishioka T, Saito H, Kurokawa T, Hirose N. Associations of eccentric force variables during jumping and eccentric lower-limb strength with vertical jump performance: A systematic review. PLoS One 2023; 18:e0289631. [PMID: 37535669 PMCID: PMC10399862 DOI: 10.1371/journal.pone.0289631] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 07/24/2023] [Indexed: 08/05/2023] Open
Abstract
The purpose of this systematic review was to summarize the associations of eccentric force variables during jumping and eccentric lower-limb strength with vertical jump performance. A literature search was conducted in September 2022 using PubMed, Web of Science, and Scopus. Thirteen cross-sectional studies investigating the relationship between eccentric force and strength variables, such as force, rate of force development (RFD), power, time, and velocity, and vertical jump performance, including the jump height, reactive strength index (RSI), and reactive strength index-modified (RSImod), were included in this systematic review. As eccentric strength, variables during the unloading-to-braking phase of countermovement jump (CMJ) (force, RFD, etc.) and the eccentric force of the squat movement and knee joint were included. The CMJ height, RSImod, and drop jump RSI were included to analyze the vertical jump performance. The modified form of the Downs and Black checklist was used to evaluate quality. Associations between the force and RFD during the descending phase of the CMJ and jump height were observed in some studies but not in others, with differences between the studies. Some studies reported associations between the force and/or RFD during the descending phase of the CMJ and RSImod of the CMJ, with no differences among their results. In addition, there are associations of the eccentric forces during squatting and knee extension with the CMJ and the drop jump heights and RSI of the drop jump. The eccentric force variables in the CMJ and RSImod are related; however, their relationship with jump height remains unclear. Furthermore, improved eccentric muscle strength may contribute to vertical jump height because of the associations of the eccentric strength during knee extension and squatting with jump height.
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Affiliation(s)
- Daichi Nishiumi
- Graduate School of Sport Sciences, Waseda University, Saitama, Japan
| | - Takuya Nishioka
- Institute of Physical Education, Keio University, Hiyoshi, Yokohama, Japan
| | - Hiromi Saito
- Graduate School of Sport Sciences, Waseda University, Saitama, Japan
| | - Takanori Kurokawa
- Graduate School of Sport Sciences, Waseda University, Saitama, Japan
| | - Norikazu Hirose
- Faculty of Sport Sciences, Waseda University, Saitama, Japan
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18
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Human and African ape myosin heavy chain content and the evolution of hominin skeletal muscle. Comp Biochem Physiol A Mol Integr Physiol 2023; 281:111415. [PMID: 36931425 DOI: 10.1016/j.cbpa.2023.111415] [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: 01/09/2023] [Revised: 03/13/2023] [Accepted: 03/13/2023] [Indexed: 03/17/2023]
Abstract
Humans are unique among terrestrial mammals in our manner of walking and running, reflecting 7 to 8 Ma of musculoskeletal evolution since diverging with the genus Pan. One component of this is a shift in our skeletal muscle biology towards a predominance of myosin heavy chain (MyHC) I isoforms (i.e. slow fibers) across our pelvis and lower limbs, which distinguishes us from chimpanzees. Here, new MyHC data from 35 pelvis and hind limb muscles of a Western gorilla (Gorilla gorilla) are presented. These data are combined with a similar chimpanzee dataset to assess the MyHC I content of humans in comparison to African apes (chimpanzees and gorillas) and other terrestrial mammals. The responsiveness of human skeletal muscle to behavioral interventions is also compared to the human-African ape differential. Humans are distinct from African apes and among a small group of terrestrial mammals whose pelvis and hind/lower limb muscle is slow fiber dominant, on average. Behavioral interventions, including immobilization, bed rest, spaceflight and exercise, can induce modest decreases and increases in human MyHC I content (i.e. -9.3% to 2.3%, n = 2033 subjects), but these shifts are much smaller than the mean human-African ape differential (i.e. 31%). Taken together, these results indicate muscle fiber content is likely an evolvable trait under selection in the hominin lineage. As such, we highlight potential targets of selection in the genome (e.g. regions that regulate MyHC content) that may play an important role in hominin skeletal muscle evolution.
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19
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Earp JE, Angelino D, Hatfield DL, Colantuono V, Jackson ER, Morgan KD, Adami A, Melanson KJ, Blazevich AJ. Differing hypertrophy patterns from open and closed kinetic chain training affect quadriceps femoris center of mass and moment of inertia. Front Physiol 2023; 14:1074705. [PMID: 36998986 PMCID: PMC10043166 DOI: 10.3389/fphys.2023.1074705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 02/27/2023] [Indexed: 03/18/2023] Open
Abstract
Purpose: To determine whether kinetic chain pattern during knee extensor strength training influences quadriceps femoris center of mass and moment of inertia about the hip in a predictable manner as such changes can affect running economy.Methods: Twelve participants completed 8 weeks of both unilateral open (OKC) and closed (CKC) kinetic chain resistance training on opposing legs. Changes in quadriceps femoris muscle volume (VOLQF), center of mass location (CoMQF), and moment of inertia (IQF) about the hip were determined from magnetic resonance images scans. Regional hemodynamics of the vastus lateralis taken at 30% and 70% of muscle length during OKC and CKC bouts early in the training program were measured using near-infrared spectroscopy (NIRS) and used post hoc to predict changes in CoMQF.Results: While increases in VOLQF were similar between OKC (Δ79.5 ± 87.9 cm3) and CKC (Δ60.2 ± 110.5 cm3, p = 0.29), the patterns of hypertrophy differed; a distal shift in CoMQF (Δ2.4 ± 0.4 cm, p < 0.001) and increase in IQF (Δ0.017 ± 0.014 kg m2, p < 0.001) occurred in OKC but not in CKC (CoMQF: Δ-2.2 ± 2.0 cm, IQF: Δ-0.022 ± 0.020 kg m2, p > 0.05). Regional hemodynamics assessed by NIRS during a single training session displayed similar exercise and regional differences and predicted 39.6% of observed changes in CoMQF.Conclusions: Exercise selection influences muscle shape sufficiently to affect CoMQF and IQF, and these changes may be predicted in part from NIRS measurements during a single workout. Given IQF is inversely related to running economy and since CKC exercise provides a more proximal pattern of hypertrophy than OKC, it may be more preferential for running. The results from the present study also highlight the potential of NIRS as a tool for predicting patterns of hypertrophy between different exercises and exercise conditions.
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Affiliation(s)
- Jacob E. Earp
- Department of Kinesiology, University of Connecticut, Storrs, CT, United States
- Department of Kinesiology, University of Rhode Island, Kingston, RI, United States
- *Correspondence: Jacob E. Earp,
| | - Domenic Angelino
- Department of Kinesiology, University of Rhode Island, Kingston, RI, United States
| | - Disa L. Hatfield
- Department of Kinesiology, University of Rhode Island, Kingston, RI, United States
| | - Vincent Colantuono
- Department of Kinesiology, University of Rhode Island, Kingston, RI, United States
| | - Euan R. Jackson
- Department of Kinesiology, University of Rhode Island, Kingston, RI, United States
| | - Kristin D. Morgan
- Department of Biomedical Engineering, University of Connecticut, Storrs, CT, United States
| | - Alessandra Adami
- Department of Kinesiology, University of Rhode Island, Kingston, RI, United States
| | - Kathleen J. Melanson
- Department of Nutrition, University of Rhode Island, Kingston, RI, United States
| | - Anthony J. Blazevich
- Centre for Exercise and Sports Science Research (CESSR), School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia
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20
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Li L, Wu K, Deng L, Liu C, Fu W. The Effects of Habitual Foot Strike Patterns on the Morphology and Mechanical Function of the Medial Gastrocnemius-Achilles Tendon Unit. Bioengineering (Basel) 2023; 10:bioengineering10020264. [PMID: 36829758 PMCID: PMC9952108 DOI: 10.3390/bioengineering10020264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 02/01/2023] [Accepted: 02/09/2023] [Indexed: 02/19/2023] Open
Abstract
As a crucial and vulnerable component of the lower extremities, the medial gastrocnemius-Achilles tendon unit (gMTU) plays a significant role in sport performance and injury prevention during long-distance running. However, how habitual foot strike patterns influence the morphology of the gMTU remains unclear. Therefore, this study aimed to explore the effects of two main foot strike patterns on the morphological and mechanical characteristics of the gMTU. Long-distance male runners with habitual forefoot (FFS group, n = 10) and rearfoot strike patterns (RFS group, n = 10) and male non-runners (NR group, n = 10) were recruited. A Terason uSmart 3300 ultrasonography system was used to image the medial gastrocnemius (MG) and Achilles tendon, Image J software to analyze the morphology, and a dynamometer to determine plantar flexion torque during maximal voluntary isometric contractions. The participants first performed a 5-minute warm up; then, the morphological measurements of MG and AT were recorded in a static condition; finally, the MVICs test was conducted to investigate the mechanical function of the gMTU. One-way ANOVA and nonparametric tests were used for data analysis. The significance level was set at a p value of <0.05. The muscle fascicle length (FL) (FFS: 67.3 ± 12.7, RFS: 62.5 ± 7.6, NRs: 55.9 ± 2.0, η2 = 0.187), normalized FL (FFS: 0.36 ± 0.48, RFS: 0.18 ± 0.03, NRs: 0.16 ± 0.01, η2 = 0.237), and pennation angle (PA) (FFS: 16.2 ± 1.9, RFS: 18.9 ± 2.8, NRs: 19.3 ± 2.4, η2 = 0.280) significantly differed between the groups. Specifically, the FL and normalized FL were longer in the FFS group than in the NR group (p < 0.05), while the PA was smaller in the FFS group than in the NR group (p < 0.05). Conclusion: Long-term running with a forefoot strike pattern could significantly affect the FL and PA of the MG. A forefoot strike pattern could lead to a longer FL and a smaller PA, indicating an FFS pattern could protect the MG from strain under repetitive high loads.
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21
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Flynn CGK, Ginkel PRV, Hubert KA, Guo Q, Hrycaj SM, McDermott AE, Madruga A, Miller AP, Wellik DM. Hox11-expressing interstitial cells contribute to adult skeletal muscle at homeostasis. Development 2023; 150:dev201026. [PMID: 36815629 PMCID: PMC10110422 DOI: 10.1242/dev.201026] [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: 06/14/2022] [Accepted: 01/13/2023] [Indexed: 02/24/2023]
Abstract
Interstitial stromal cells play critical roles in muscle development, regeneration and repair and we have previously reported that Hoxa11 and Hoxd11 are expressed in the interstitial cells of muscles attached to the zeugopod, and are crucial for the proper embryonic patterning of these muscles. Hoxa11eGFP expression continues in a subset of muscle interstitial cells through adult stages. The induction of Hoxa11-CreERT2-mediated lineage reporting (Hoxa11iTom) at adult stages in mouse results in lineage induction only in the interstitial cells. However, Hoxa11iTom+ cells progressively contribute to muscle fibers at subsequent stages. The contribution to myofibers exceeds parallel Pax7-CreERT2-mediated lineage labeling. Nuclear-specific lineage labeling demonstrates that Hoxa11-expressing interstitial cells contribute nuclear contents to myofibers. Crucially, at no point after Hoxa11iTom induction are satellite cells lineage labeled. When examined in vitro, isolated Hoxa11iTom+ interstitial cells are not capable of forming myotubes, but Hoxa11iTom+ cells can contribute to differentiating myotubes, supporting Hox-expressing interstitial cells as a new population of muscle progenitors, but not stem cells. This work adds to a small but growing body of evidence that supports a satellite cell-independent source of muscle tissue in vivo.
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Affiliation(s)
- Corey G. K. Flynn
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
| | - Paul R. Van Ginkel
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
| | - Katharine A. Hubert
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
- Genetics Training Program, University of Wisconsin-Madison, Madison, WI 53703, USA
| | - Qingyuan Guo
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
- Cell and Molecular Biology Training Program, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Steven M. Hrycaj
- Department of Pathology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Aubrey E. McDermott
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
| | - Angelo Madruga
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
| | - Anna P. Miller
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
| | - Deneen M. Wellik
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
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22
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Hou YC, Wu JM, Chen KY, Wu MH, Yang PJ, Lee PC, Chen PD, Yeh SL, Lin MT. Glutamine and leucine administration attenuates muscle atrophy in sepsis. Life Sci 2023; 314:121327. [PMID: 36584912 DOI: 10.1016/j.lfs.2022.121327] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/02/2022] [Accepted: 12/22/2022] [Indexed: 12/28/2022]
Abstract
AIMS This study investigated whether l-glutamine (Gln) and/or l-leucine (Leu) administration could attenuate muscle atrophy in a mouse model of cecal ligation and puncture (CLP)-induced sepsis. MATERIALS AND METHODS Septic mice were given a daily intraperitoneal injection of Gln, Leu, or Gln plus Leu, and mice were sacrificed on either day 1 or 4 after CLP. Blood and muscles were collected for analysis of amino acid contents and markers related to protein degradation, muscle regeneration, and protein synthesis. KEY FINDINGS Leu treatment alone increased both muscle mass and total muscle protein content on day 4 after CLP. Gln administration reduced muscular Gln contents on day 1 and enhanced plasma Gln levels on day 4. Higher plasma branched-chain amino acid (BCAA) abundances and lower muscular BCAA levels were observed in Leu-treated mice on day 4. Gln and Leu individually suppressed muscle expressions of the E3 ubiquitin ligase genes, Trim63 and Fbxo32, on day 4 after CLP. As to muscle expressions of myogenic genes, both Gln and Leu upregulated Myog expression on day 1, but Leu alone enhanced Myf5 gene expression, whereas Gln plus Leu increased MyoD and Myog expression levels on day 4. Akt/mammalian target of rapamycin (mTOR) signaling was only activated by Gln and Leu when individually administered. SIGNIFICANCE Gln and/or Leu administration reduces sepsis-induced muscle degradation and promotes myogenic gene expressions. Leu treatment alone had more-pronounced effects on maintaining muscle mass during sepsis. A combination of Gln and Leu failed to show synergistic effects on alleviating sepsis-induced muscle atrophy.
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Affiliation(s)
- Yu-Chen Hou
- Master Program in Food Safety, College of Nutrition, Taipei Medical University, Taipei, Taiwan; School of Food Safety, College of Nutrition, Taipei Medical University, Taipei, Taiwan; Nutrition Research Center, Taipei Medical University Hospital, Taipei, Taiwan
| | - Jin-Ming Wu
- Department of Surgery, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Kuen-Yuan Chen
- Department of Surgery, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ming-Hsun Wu
- Department of Surgery, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Po-Jen Yang
- Department of Surgery, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Po-Chu Lee
- Department of Surgery, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Po-Da Chen
- Department of Surgery, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Sung-Ling Yeh
- Department of Surgery, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ming-Tsan Lin
- Department of Surgery, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan.
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23
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Bartman CR, Weilandt DR, Shen Y, Lee WD, Han Y, TeSlaa T, Jankowski CSR, Samarah L, Park NR, da Silva-Diz V, Aleksandrova M, Gultekin Y, Marishta A, Wang L, Yang L, Roichman A, Bhatt V, Lan T, Hu Z, Xing X, Lu W, Davidson S, Wühr M, Vander Heiden MG, Herranz D, Guo JY, Kang Y, Rabinowitz JD. Slow TCA flux and ATP production in primary solid tumours but not metastases. Nature 2023; 614:349-357. [PMID: 36725930 PMCID: PMC10288502 DOI: 10.1038/s41586-022-05661-6] [Citation(s) in RCA: 87] [Impact Index Per Article: 87.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 12/14/2022] [Indexed: 02/03/2023]
Abstract
Tissues derive ATP from two pathways-glycolysis and the tricarboxylic acid (TCA) cycle coupled to the electron transport chain. Most energy in mammals is produced via TCA metabolism1. In tumours, however, the absolute rates of these pathways remain unclear. Here we optimize tracer infusion approaches to measure the rates of glycolysis and the TCA cycle in healthy mouse tissues, Kras-mutant solid tumours, metastases and leukaemia. Then, given the rates of these two pathways, we calculate total ATP synthesis rates. We find that TCA cycle flux is suppressed in all five primary solid tumour models examined and is increased in lung metastases of breast cancer relative to primary orthotopic tumours. As expected, glycolysis flux is increased in tumours compared with healthy tissues (the Warburg effect2,3), but this increase is insufficient to compensate for low TCA flux in terms of ATP production. Thus, instead of being hypermetabolic, as commonly assumed, solid tumours generally produce ATP at a slower than normal rate. In mouse pancreatic cancer, this is accommodated by the downregulation of protein synthesis, one of this tissue's major energy costs. We propose that, as solid tumours develop, cancer cells shed energetically expensive tissue-specific functions, enabling uncontrolled growth despite a limited ability to produce ATP.
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Affiliation(s)
- Caroline R Bartman
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ, USA
- Ludwig Institute for Cancer Research, Princeton University, Princeton, NJ, USA
| | - Daniel R Weilandt
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ, USA
- Ludwig Institute for Cancer Research, Princeton University, Princeton, NJ, USA
| | - Yihui Shen
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Won Dong Lee
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Yujiao Han
- Ludwig Institute for Cancer Research, Princeton University, Princeton, NJ, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Tara TeSlaa
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ, USA
- Ludwig Institute for Cancer Research, Princeton University, Princeton, NJ, USA
- Department of Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, USA
| | - Connor S R Jankowski
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ, USA
- Ludwig Institute for Cancer Research, Princeton University, Princeton, NJ, USA
| | - Laith Samarah
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ, USA
- Ludwig Institute for Cancer Research, Princeton University, Princeton, NJ, USA
| | - Noel R Park
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | | | - Maya Aleksandrova
- Cancer Institute of New Jersey, Rutgers University, New Brunswick, NJ, USA
| | - Yetis Gultekin
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Boston, MA, USA
- Department of Biology, Massachusetts Institute of Technology, Boston, MA, USA
| | - Argit Marishta
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Lin Wang
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ, USA
- Ludwig Institute for Cancer Research, Princeton University, Princeton, NJ, USA
- Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Lifeng Yang
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ, USA
- Ludwig Institute for Cancer Research, Princeton University, Princeton, NJ, USA
- Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Shanghai, China
| | - Asael Roichman
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ, USA
- Ludwig Institute for Cancer Research, Princeton University, Princeton, NJ, USA
| | - Vrushank Bhatt
- Cancer Institute of New Jersey, Rutgers University, New Brunswick, NJ, USA
| | - Taijin Lan
- Cancer Institute of New Jersey, Rutgers University, New Brunswick, NJ, USA
| | - Zhixian Hu
- Cancer Institute of New Jersey, Rutgers University, New Brunswick, NJ, USA
| | - Xi Xing
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ, USA
- Ludwig Institute for Cancer Research, Princeton University, Princeton, NJ, USA
| | - Wenyun Lu
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ, USA
- Ludwig Institute for Cancer Research, Princeton University, Princeton, NJ, USA
| | - Shawn Davidson
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Martin Wühr
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Matthew G Vander Heiden
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Boston, MA, USA
- Department of Biology, Massachusetts Institute of Technology, Boston, MA, USA
| | - Daniel Herranz
- Cancer Institute of New Jersey, Rutgers University, New Brunswick, NJ, USA
| | | | - Yibin Kang
- Ludwig Institute for Cancer Research, Princeton University, Princeton, NJ, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Joshua D Rabinowitz
- Department of Chemistry, Princeton University, Princeton, NJ, USA.
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ, USA.
- Ludwig Institute for Cancer Research, Princeton University, Princeton, NJ, USA.
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24
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Kiriaev L, Baumann CW, Lindsay A. Eccentric contraction-induced strength loss in dystrophin-deficient muscle: Preparations, protocols, and mechanisms. J Gen Physiol 2023; 155:213810. [PMID: 36651896 PMCID: PMC9856740 DOI: 10.1085/jgp.202213208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 12/01/2022] [Accepted: 12/28/2022] [Indexed: 01/19/2023] Open
Abstract
The absence of dystrophin hypersensitizes skeletal muscle of lower and higher vertebrates to eccentric contraction (ECC)-induced strength loss. Loss of strength can be accompanied by transient and reversible alterations to sarcolemmal excitability and disruption, triad dysfunction, and aberrations in calcium kinetics and reactive oxygen species production. The degree of ECC-induced strength loss, however, appears dependent on several extrinsic and intrinsic factors such as vertebrate model, skeletal muscle preparation (in vivo, in situ, or ex vivo), skeletal muscle hierarchy (single fiber versus whole muscle and permeabilized versus intact), strength production, fiber branching, age, and genetic background, among others. Consistent findings across research groups show that dystrophin-deficient fast(er)-twitch muscle is hypersensitive to ECCs relative to wildtype muscle, but because preparations are highly variable and sensitivity to ECCs are used repeatedly to determine efficacy of many preclinical treatments, it is critical to evaluate the impact of skeletal muscle preparations on sensitivity to ECC-induced strength loss in dystrophin-deficient skeletal muscle. Here, we review and discuss variations in skeletal muscle preparations to evaluate the factors responsible for variations and discrepancies between research groups. We further highlight that dystrophin-deficiency, or loss of the dystrophin-glycoprotein complex in skeletal muscle, is not a prerequisite for accelerated strength loss-induced by ECCs.
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Affiliation(s)
- Leonit Kiriaev
- Muscle Research Group, Murdoch Children’s Research Institute, Parkville, Victoria, Australia,School of Medicine, Western Sydney University, Campbelltown, New South Wales, Australia
| | - Cory W. Baumann
- Ohio Musculoskeletal and Neurological Institute (OMNI), Ohio University, Athens, OH, USA,Department of Biomedical Sciences, Ohio University, Athens, OH, USA
| | - Angus Lindsay
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia,Correspondence to Angus Lindsay:
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25
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De Biase D, Pagano TB, Malanga D, Russo V, Piegari G, d'Aquino I, Iovane V, Scarfò M, Papparella S, Wojcik S, Paciello O. Identification of vacuolar autophagic aggregates in the skeletal muscles of inbred C57BL/6NCrl mice. Lab Anim 2023:236772221138942. [PMID: 36601775 DOI: 10.1177/00236772221138942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
A comprehensive pathological analysis of inbred strains is essential to define strain-specific spontaneous lesions and to understand whether a specific phenotype results from experimental intervention or reflects a naturally occurring disease. This study aimed to report and describe a novel condition affecting the skeletal muscles of an inbred C57BL/6NCrl mouse colony characterised by large sarcoplasmic vacuoles in the muscle fibres of male mice in the subsarcolemmal spaces and the intermyofibrillary network. There was no muscle weakness, loss of ambulation or cardiac/respiratory involvement. Post-mortem evaluation and histological analysis excluded the presence of pathological accumulations or lesions in other tissues and organs. Changes were seen in fibre size, with many hypotrophic and some slightly hypertrophic fibres. Histological, immunohistochemical and molecular analyses of the vacuolar content revealed dysregulation of the autophagy machinery while ruling out a morphologically similar condition marked by the accumulation of tubular aggregates.
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Affiliation(s)
| | - Teresa Bruna Pagano
- Department of Veterinary Medicine and Animal Production University of Naples 'Federico II', Italy
| | - Donatella Malanga
- Department of Experimental and Clinical Medicine, University 'Magna Graecia' of Catanzaro Medical School, Italy
| | - Valeria Russo
- Department of Veterinary Medicine and Animal Production University of Naples 'Federico II', Italy
| | - Giuseppe Piegari
- Department of Veterinary Medicine and Animal Production University of Naples 'Federico II', Italy
| | - Ilaria d'Aquino
- Department of Veterinary Medicine and Animal Production University of Naples 'Federico II', Italy
| | - Valentina Iovane
- Department of Agricultural Sciences, University of Naples 'Federico II', Italy
| | | | - Serenella Papparella
- Department of Veterinary Medicine and Animal Production University of Naples 'Federico II', Italy
| | - Slawomir Wojcik
- Department of Anatomy and Neurobiology, Medical University of Gdansk, Poland
| | - Orlando Paciello
- Department of Veterinary Medicine and Animal Production University of Naples 'Federico II', Italy
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26
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Wintzinger M, Miz K, York A, Demonbreun AR, Molkentin JD, McNally EM, Quattrocelli M. Effects of Glucocorticoids in Murine Models of Duchenne and Limb-Girdle Muscular Dystrophy. Methods Mol Biol 2023; 2587:467-478. [PMID: 36401044 PMCID: PMC9816991 DOI: 10.1007/978-1-0716-2772-3_24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In vivo testing of glucocorticoid steroids in dystrophic mice offers important insights in benefits and risks of those drugs in the pathological context of muscular dystrophy. Frequency of dosing changes the spectrum of glucocorticoid effects on muscle and metabolic homeostasis. Here, we describe a combination of non-invasive and invasive methods to quantitatively discriminate the specific effects of intermittent (once-weekly) versus mainstay (once-daily) regimens on muscle fibrosis, muscle function, and metabolic homeostasis in murine models of Duchenne and limb-girdle muscular dystrophies.
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Affiliation(s)
- Michelle Wintzinger
- Division of Molecular Cardiovascular Biology, Heart Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
| | - Karen Miz
- Division of Molecular Cardiovascular Biology, Heart Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
| | - Allen York
- Division of Molecular Cardiovascular Biology, Heart Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
| | - Alexis R. Demonbreun
- Center for Genetic Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Jeffery D. Molkentin
- Division of Molecular Cardiovascular Biology, Heart Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Elizabeth M. McNally
- Center for Genetic Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Mattia Quattrocelli
- Division of Molecular Cardiovascular Biology, Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA. .,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
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27
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Werkhausen A, Gløersen Ø, Nordez A, Paulsen G, Bojsen-Møller J, Seynnes OR. Rate of force development relationships to muscle architecture and contractile behavior in the human vastus lateralis. Sci Rep 2022; 12:21816. [PMID: 36528647 PMCID: PMC9759581 DOI: 10.1038/s41598-022-26379-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022] Open
Abstract
In this study, we tested the hypotheses that (i) rate of force development (RFD) is correlated to muscle architecture and dynamics and that (ii) force-length-velocity properties limit knee extensor RFD. Twenty-one healthy participants were tested using ultrasonography and dynamometry. Vastus lateralis optimal fascicle length, fascicle velocity, change in pennation angle, change in muscle length, architectural gear ratio, and force were measured during rapid fixed-end contractions at 60° knee angle to determine RFD. Isokinetic and isometric tests were used to estimate individual force-length-velocity properties, to evaluate force production relative to maximal potential. Correlation analyses were performed between force and muscle parameters for the first three 50 ms intervals. RFD was not related to optimal fascicle length for any measured time interval, but RFD was positively correlated to fascicle shortening velocity during all intervals (r = 0.49-0.69). Except for the first interval, RFD was also related to trigonometry-based changes in muscle length and pennation angle (r = 0.45-0.63) but not to architectural gear ratio. Participants reached their individual vastus lateralis force-length-velocity potential (i.e. their theoretical maximal force at a given length and shortening velocity) after 62 ± 24 ms. Our results confirm the theoretical importance of fascicle shortening velocity and force-length-velocity properties for rapid force production and suggest a role of fascicle rotation.
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Affiliation(s)
- Amelie Werkhausen
- grid.412285.80000 0000 8567 2092Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| | - Øyvind Gløersen
- grid.4319.f0000 0004 0448 3150SINTEF Digital, Smart Sensors and Microsystems, Oslo, Norway
| | - Antoine Nordez
- grid.4817.a0000 0001 2189 0784Movement-Interactions-Performance, MIP, UR 4334, Nantes Université, 44000 Nantes, France ,grid.440891.00000 0001 1931 4817Institut Universitaire de France (IUF), Paris, France
| | - Gøran Paulsen
- grid.412285.80000 0000 8567 2092Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| | - Jens Bojsen-Møller
- grid.10825.3e0000 0001 0728 0170Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Olivier R. Seynnes
- grid.412285.80000 0000 8567 2092Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
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28
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Katti P, Ajayi PT, Aponte A, Bleck CKE, Glancy B. Identification of evolutionarily conserved regulators of muscle mitochondrial network organization. Nat Commun 2022; 13:6622. [PMID: 36333356 PMCID: PMC9636386 DOI: 10.1038/s41467-022-34445-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 10/25/2022] [Indexed: 11/06/2022] Open
Abstract
Mitochondrial networks provide coordinated energy distribution throughout muscle cells. However, pathways specifying mitochondrial networks are incompletely understood and it is unclear how they might affect contractile fiber-type. Here, we show that natural energetic demands placed on Drosophila melanogaster muscles yield native cell-types among which contractile and mitochondrial network-types are regulated differentially. Proteomic analyses of indirect flight, jump, and leg muscles, together with muscles misexpressing known fiber-type specification factor salm, identified transcription factors H15 and cut as potential mitochondrial network regulators. We demonstrate H15 operates downstream of salm regulating flight muscle contractile and mitochondrial network-type. Conversely, H15 regulates mitochondrial network configuration but not contractile type in jump and leg muscles. Further, we find that cut regulates salm expression in flight muscles and mitochondrial network configuration in leg muscles. These data indicate cell type-specific regulation of muscle mitochondrial network organization through evolutionarily conserved transcription factors cut, salm, and H15.
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Affiliation(s)
- Prasanna Katti
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Peter T Ajayi
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Angel Aponte
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Christopher K E Bleck
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Brian Glancy
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.
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29
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Lloyd EM, Hepburn MS, Li J, Mowla A, Hwang Y, Choi YS, Grounds MD, Kennedy BF. Three-dimensional mechanical characterization of murine skeletal muscle using quantitative micro-elastography. BIOMEDICAL OPTICS EXPRESS 2022; 13:5879-5899. [PMID: 36733728 PMCID: PMC9872891 DOI: 10.1364/boe.471062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 08/29/2022] [Accepted: 09/02/2022] [Indexed: 06/18/2023]
Abstract
Skeletal muscle function is governed by both the mechanical and structural properties of its constituent tissues, which are both modified by disease. Characterizing the mechanical properties of skeletal muscle tissue at an intermediate scale, i.e., between that of cells and organs, can provide insight into diseases such as muscular dystrophies. In this study, we use quantitative micro-elastography (QME) to characterize the micro-scale elasticity of ex vivo murine skeletal muscle in three-dimensions in whole muscles. To address the challenge of achieving high QME image quality with samples featuring uneven surfaces and geometry, we encapsulate the muscles in transparent hydrogels with flat surfaces. Using this method, we study aging and disease in quadriceps tissue by comparing normal wild-type (C57BL/6J) mice with dysferlin-deficient BLAJ mice, a model for the muscular dystrophy dysferlinopathy, at 3, 10, and 24 months of age (sample size of three per group). We observe a 77% decrease in elasticity at 24 months in dysferlin-deficient quadriceps compared to wild-type quadriceps.
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Affiliation(s)
- Erin M. Lloyd
- Department of Anatomy, Physiology and Human Biology, School of Human Sciences, The University of Western Australia, 35 Stirling Highway, Perth, Western Australia, 6009, Australia
- These authors contributed equally to this work
| | - Matt S. Hepburn
- BRITElab, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, 6009, Australia and Centre for Medical Research, The University of Western Australia, Perth, Western Australia, 6009, Australia
- Department of Electrical, Electronic & Computer Engineering, School of Engineering, The University of Western Australia, 35, Stirling Highway, Perth, Western Australia, 6009, Australia
- These authors contributed equally to this work
| | - Jiayue Li
- BRITElab, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, 6009, Australia and Centre for Medical Research, The University of Western Australia, Perth, Western Australia, 6009, Australia
- Department of Electrical, Electronic & Computer Engineering, School of Engineering, The University of Western Australia, 35, Stirling Highway, Perth, Western Australia, 6009, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Australia
| | - Alireza Mowla
- BRITElab, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, 6009, Australia and Centre for Medical Research, The University of Western Australia, Perth, Western Australia, 6009, Australia
- Department of Electrical, Electronic & Computer Engineering, School of Engineering, The University of Western Australia, 35, Stirling Highway, Perth, Western Australia, 6009, Australia
| | - Yongsung Hwang
- Soonchunhyang Institute of Medi-Bio Science, Soonchunhyang University, Cheonan-si, Chungcheongnam-do, 31151, Republic of Korea
| | - Yu Suk Choi
- Department of Anatomy, Physiology and Human Biology, School of Human Sciences, The University of Western Australia, 35 Stirling Highway, Perth, Western Australia, 6009, Australia
| | - Miranda D. Grounds
- Department of Anatomy, Physiology and Human Biology, School of Human Sciences, The University of Western Australia, 35 Stirling Highway, Perth, Western Australia, 6009, Australia
| | - Brendan F. Kennedy
- BRITElab, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, 6009, Australia and Centre for Medical Research, The University of Western Australia, Perth, Western Australia, 6009, Australia
- Department of Electrical, Electronic & Computer Engineering, School of Engineering, The University of Western Australia, 35, Stirling Highway, Perth, Western Australia, 6009, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Australia
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30
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Collins KH, Gui C, Ely EV, Lenz KL, Harris CA, Guilak F, Meyer GA. Leptin mediates the regulation of muscle mass and strength by adipose tissue. J Physiol 2022; 600:3795-3817. [PMID: 35844058 PMCID: PMC9378542 DOI: 10.1113/jp283034] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 07/04/2022] [Indexed: 02/01/2023] Open
Abstract
Adipose tissue secretes numerous cytokines (termed 'adipokines') that have known or hypothesized actions on skeletal muscle. The majority of adipokines have been implicated in the pathological link between excess adipose and muscle insulin resistance, but approximately half also have documented in vitro effects on myogenesis and/or hypertrophy. This complexity suggests a potential dual role for adipokines in the regulation of muscle mass in homeostasis and the development of pathology. In this study, we used lipodystrophic 'fat-free' mice to demonstrate that adipose tissue is indeed necessary for the development of normal muscle mass and strength. Fat-free mice had significantly reduced mass (∼15%) and peak contractile tension (∼20%) of fast-twitch muscles, a slowing of contractile dynamics and decreased cross-sectional area of fast twitch fibres compared to wild-type littermates. These deficits in mass and contractile tension were fully rescued by reconstitution of ∼10% of normal adipose mass, indicating that this phenotype is the direct consequence of absent adipose. We then showed that the rescue is solely mediated by the adipokine leptin, as similar reconstitution of adipose from leptin-knockout mice fails to rescue mass or strength. Together, these data indicate that the development of muscle mass and strength in wild-type mice is dependent on adipose-secreted leptin. This finding extends our current understanding of the multiple roles of adipokines in physiology as well as disease pathophysiology to include a critical role for the adipokine leptin in muscle homeostasis. KEY POINTS: Adipose-derived cytokines (adipokines) have long been implicated in the pathogenesis of insulin resistance in obesity but likely have other under-appreciated roles in muscle physiology. Here we use a fat-free mouse to show that adipose tissue is necessary for the normal development of muscle mass and strength. Through add-back of genetically modified adipose tissue we show that leptin is the key adipokine mediating this regulation. This expands our understanding of leptin's role in adipose-muscle signalling to include development and homeostasis and adds the surprising finding that leptin is the sole mediator of the maintenance of muscle mass and strength by adipose tissue.
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Affiliation(s)
- Kelsey H. Collins
- Department of Orthopaedic SurgeryWashington University in St. LouisMOUSA,Shriners Hospitals for ChildrenSt LouisMOUSA,Center of Regenerative MedicineWashington University in St. LouisMOUSA
| | - Chang Gui
- Department of Biomedical EngineeringWashington University in St. LouisMOUSA,Program in Physical TherapyWashington UniversitySt LouisMOUSA
| | - Erica V. Ely
- Department of Orthopaedic SurgeryWashington University in St. LouisMOUSA,Shriners Hospitals for ChildrenSt LouisMOUSA,Center of Regenerative MedicineWashington University in St. LouisMOUSA,Department of Biomedical EngineeringWashington University in St. LouisMOUSA
| | - Kristin L. Lenz
- Department of Orthopaedic SurgeryWashington University in St. LouisMOUSA,Shriners Hospitals for ChildrenSt LouisMOUSA,Center of Regenerative MedicineWashington University in St. LouisMOUSA
| | - Charles A. Harris
- Division of EndocrinologyMetabolism & Lipid ResearchWashington UniversitySt LouisMissouriUSA
| | - Farshid Guilak
- Department of Orthopaedic SurgeryWashington University in St. LouisMOUSA,Shriners Hospitals for ChildrenSt LouisMOUSA,Center of Regenerative MedicineWashington University in St. LouisMOUSA,Department of Biomedical EngineeringWashington University in St. LouisMOUSA
| | - Gretchen A. Meyer
- Department of Orthopaedic SurgeryWashington University in St. LouisMOUSA,Center of Regenerative MedicineWashington University in St. LouisMOUSA,Department of Biomedical EngineeringWashington University in St. LouisMOUSA,Program in Physical TherapyWashington UniversitySt LouisMOUSA,Department of NeurologyWashington University in St. LouisSt LouisMOUSA
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Charles J, Kissane R, Hoehfurtner T, Bates KT. From fibre to function: are we accurately representing muscle architecture and performance? Biol Rev Camb Philos Soc 2022; 97:1640-1676. [PMID: 35388613 PMCID: PMC9540431 DOI: 10.1111/brv.12856] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 03/22/2022] [Accepted: 03/25/2022] [Indexed: 12/11/2022]
Abstract
The size and arrangement of fibres play a determinate role in the kinetic and energetic performance of muscles. Extrapolations between fibre architecture and performance underpin our understanding of how muscles function and how they are adapted to power specific motions within and across species. Here we provide a synopsis of how this 'fibre to function' paradigm has been applied to understand muscle design, performance and adaptation in animals. Our review highlights the widespread application of the fibre to function paradigm across a diverse breadth of biological disciplines but also reveals a potential and highly prevalent limitation running through past studies. Specifically, we find that quantification of muscle architectural properties is almost universally based on an extremely small number of fibre measurements. Despite the volume of research into muscle properties, across a diverse breadth of research disciplines, the fundamental assumption that a small proportion of fibre measurements can accurately represent the architectural properties of a muscle has never been quantitatively tested. Subsequently, we use a combination of medical imaging, statistical analysis, and physics-based computer simulation to address this issue for the first time. By combining diffusion tensor imaging (DTI) and deterministic fibre tractography we generated a large number of fibre measurements (>3000) rapidly for individual human lower limb muscles. Through statistical subsampling simulations of these measurements, we demonstrate that analysing a small number of fibres (n < 25) typically used in previous studies may lead to extremely large errors in the characterisation of overall muscle architectural properties such as mean fibre length and physiological cross-sectional area. Through dynamic musculoskeletal simulations of human walking and jumping, we demonstrate that recovered errors in fibre architecture characterisation have significant implications for quantitative predictions of in-vivo dynamics and muscle fibre function within a species. Furthermore, by applying data-subsampling simulations to comparisons of muscle function in humans and chimpanzees, we demonstrate that error magnitudes significantly impact both qualitative and quantitative assessment of muscle specialisation, potentially generating highly erroneous conclusions about the absolute and relative adaption of muscles across species and evolutionary transitions. Our findings have profound implications for how a broad diversity of research fields quantify muscle architecture and interpret muscle function.
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Affiliation(s)
- James Charles
- Structure and Motion Lab, Comparative Biomedical Sciences, Royal Veterinary College, Hawkshead Lane, Hatfield, Hertfordshire, AL9 7TA, U.K.,Department of Musculoskeletal & Ageing Science, Institute of Life Course & Medical Sciences, University of Liverpool, The William Henry Duncan Building, 6 West Derby Street, Liverpool, L7 8TX, U.K
| | - Roger Kissane
- Department of Musculoskeletal & Ageing Science, Institute of Life Course & Medical Sciences, University of Liverpool, The William Henry Duncan Building, 6 West Derby Street, Liverpool, L7 8TX, U.K
| | - Tatjana Hoehfurtner
- School of Life Sciences, University of Lincoln, Joseph Banks Laboratories, Green Lane, Lincoln, LN6 7DL, U.K
| | - Karl T Bates
- Department of Musculoskeletal & Ageing Science, Institute of Life Course & Medical Sciences, University of Liverpool, The William Henry Duncan Building, 6 West Derby Street, Liverpool, L7 8TX, U.K
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32
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Hurley KL, Bassett JR, Monroy JA. Active muscle stiffness is reduced during rapid unloading in muscles from TtnD112-158 mice with a large deletion to PEVK titin. J Exp Biol 2022; 225:276067. [DOI: 10.1242/jeb.243584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 07/13/2022] [Indexed: 11/20/2022]
Abstract
Evidence suggests that the giant muscle protein, titin functions as a tunable spring in active muscle. However, the mechanisms for increasing titin stiffness with activation are not well understood. Previous studies have suggested that during muscle activation, titin binds to actin which engages the PEVK region of titin thereby increasing titin stiffness. In this study, we investigated the role of PEVK titin in active muscle stiffness during rapid unloading. We measured elastic recoil of active and passive soleus muscles from TtnD112-158 mice characterized by a 75% deletion of PEVK titin and increased passive stiffness. We hypothesized that activated TtnD112-158 muscles are more stiff than wild type muscles due to the increased stiffness of PEVK titin. Using a servomotor force lever, we compared the stress–strain relationships of elastic elements in active and passive muscles during rapid unloading and quantified the change in stiffness upon activation. Results show that the elastic modulus of TtnD112-158 muscles increased with activation. However, elastic elements developed force at 7% longer lengths and exhibited 50% lower active stiffness in TtnD112-158 soleus muscles than wild type muscles. Thus, despite having a shorter, stiffer PEVK segment, during rapid unloading, TtnD112-158 soleus muscles exhibited reduced active stiffness compared to wild type soleus muscles. These results are consistent with the idea that PEVK titin contributes to active muscle stiffness, however, the reduction in active stiffness of TtnD112-158 muscles suggests that other mechanisms compensate for the increased PEVK stiffness.
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Affiliation(s)
| | | | - Jenna A. Monroy
- 3 W.M. Keck Science Department, Claremont Colleges, Claremont, CA, USA
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Removal of MuRF1 Increases Muscle Mass in Nemaline Myopathy Models, but Does Not Provide Functional Benefits. Int J Mol Sci 2022; 23:ijms23158113. [PMID: 35897687 PMCID: PMC9331820 DOI: 10.3390/ijms23158113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 07/18/2022] [Accepted: 07/20/2022] [Indexed: 11/16/2022] Open
Abstract
Nemaline myopathy (NM) is characterized by skeletal muscle weakness and atrophy. No curative treatments exist for this debilitating disease. NM is caused by mutations in proteins involved in thin-filament function, turnover, and maintenance. Mutations in nebulin, encoded by NEB, are the most common cause. Skeletal muscle atrophy is tightly linked to upregulation of MuRF1, an E3 ligase, that targets proteins for proteasome degradation. Here, we report a large increase in MuRF1 protein levels in both patients with nebulin-based NM, also named NEM2, and in mouse models of the disease. We hypothesized that knocking out MuRF1 in animal models of NM with muscle atrophy would ameliorate the muscle deficits. To test this, we crossed MuRF1 KO mice with two NEM2 mouse models, one with the typical form and the other with the severe form. The crosses were viable, and muscles were studied in mice at 3 months of life. Ultrastructural examination of gastrocnemius muscle lacking MuRF1 and with severe NM revealed a small increase in vacuoles, but no significant change in the myofibrillar fractional area. MuRF1 deficiency led to increased weights of various muscle types in the NM models. However, this increase in muscle size was not associated with increased in vivo or in vitro force production. We conclude that knocking out MuRF1 in NEM2 mice increases muscle size, but does not improve muscle function.
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Olesen AT, Malchow-Møller L, Bendixen RD, Kjær M, Mackey AL, Magnusson SP, Svensson RB. Intramuscular connective tissue content and mechanical properties: Influence of aging and physical activity in mice. Exp Gerontol 2022; 166:111893. [PMID: 35870752 DOI: 10.1016/j.exger.2022.111893] [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: 04/12/2022] [Revised: 07/05/2022] [Accepted: 07/09/2022] [Indexed: 11/25/2022]
Abstract
Aging is accompanied by morphological and mechanical changes to the intramuscular connective tissue (IMCT) of skeletal muscles, but whether physical exercise can influence these changes is debated. We investigated the effects of aging and exercise with high or low resistance on composition and mechanical properties of the IMCT, including direct measurements on isolated IMCT which has rarely been reported. Middle-aged (11 months, n = 24) and old (22 months, n = 18) C57BL/6 mice completed either high (HR) or low (LR) resistance voluntary wheel running or were sedentary (SED) for 10 weeks. Passive mechanical properties of the intact soleus and plantaris muscles and the isolated IMCT of the plantaris muscle were measured in vitro. IMCT thickness was measured on picrosirius red stained cross sections of the gastrocnemius and soleus muscle and for the gastrocnemius hydroxyproline content was quantified biochemically and advanced glycation end-products (AGEs) estimated by fluorometry. Mechanical stiffness, IMCT content and total AGEs were all elevated with aging in agreement with previous findings but were largely unaffected by training. Conclusion: IMCT accumulated with aging with a proportional increase in mechanical stiffness, but even the relatively high exercise volume achieved with voluntary wheel-running with or without resistance did not significantly influence these changes.
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Affiliation(s)
- Annesofie T Olesen
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery, Copenhagen University Hospital - Bispebjerg and Frederiksberg, Denmark; Center for Healthy Aging, Department of Clinical Medicine, University of Copenhagen, Denmark
| | - Lasse Malchow-Møller
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery, Copenhagen University Hospital - Bispebjerg and Frederiksberg, Denmark; Center for Healthy Aging, Department of Clinical Medicine, University of Copenhagen, Denmark
| | - Rune D Bendixen
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery, Copenhagen University Hospital - Bispebjerg and Frederiksberg, Denmark; Center for Healthy Aging, Department of Clinical Medicine, University of Copenhagen, Denmark
| | - Michael Kjær
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery, Copenhagen University Hospital - Bispebjerg and Frederiksberg, Denmark; Center for Healthy Aging, Department of Clinical Medicine, University of Copenhagen, Denmark
| | - Abigail L Mackey
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery, Copenhagen University Hospital - Bispebjerg and Frederiksberg, Denmark; Center for Healthy Aging, Department of Clinical Medicine, University of Copenhagen, Denmark; XLab, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - S Peter Magnusson
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery, Copenhagen University Hospital - Bispebjerg and Frederiksberg, Denmark; Center for Healthy Aging, Department of Clinical Medicine, University of Copenhagen, Denmark; Department of Physical and Occupational Therapy, Copenhagen University Hospital - Bispebjerg and Frederiksberg, Denmark
| | - Rene B Svensson
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery, Copenhagen University Hospital - Bispebjerg and Frederiksberg, Denmark; Center for Healthy Aging, Department of Clinical Medicine, University of Copenhagen, Denmark.
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35
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Sakamoto M. Estimating bite force in extinct dinosaurs using phylogenetically predicted physiological cross-sectional areas of jaw adductor muscles. PeerJ 2022; 10:e13731. [PMID: 35846881 PMCID: PMC9285543 DOI: 10.7717/peerj.13731] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 06/23/2022] [Indexed: 01/17/2023] Open
Abstract
I present a Bayesian phylogenetic predictive modelling (PPM) framework that allows the prediction of muscle parameters (physiological cross-sectional area, A Phys) in extinct archosaurs from skull width (W Sk) and phylogeny. This approach is robust to phylogenetic uncertainty and highly versatile given its ability to base predictions on simple, readily available predictor variables. The PPM presented here has high prediction accuracy (up to 95%), with downstream biomechanical modelling yielding bite force estimates that are in line with previous estimates based on muscle parameters from reconstructed muscles. This approach does not replace muscle reconstructions but one that provides a powerful means to predict A Phys from skull geometry and phylogeny to the same level of accuracy as that measured from reconstructed muscles in species for which soft tissue data are unavailable or difficult to obtain.
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Deyhle MR, Callaway CS, Neyroud D, D’Lugos AC, Judge SM, Judge AR. Depleting Ly6G Positive Myeloid Cells Reduces Pancreatic Cancer-Induced Skeletal Muscle Atrophy. Cells 2022; 11:1893. [PMID: 35741022 PMCID: PMC9221479 DOI: 10.3390/cells11121893] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 06/02/2022] [Accepted: 06/08/2022] [Indexed: 12/22/2022] Open
Abstract
Immune cells can mount desirable anti-cancer immunity. However, some immune cells can support cancer disease progression. The presence of cancer can lead to production of immature myeloid cells from the bone marrow known as myeloid-derived suppressor cells (MDSCs). The immunosuppressive and pro-tumorigenic effects of MDSCs are well understood. Whether MDSCs are involved in promoting cancer cachexia is not well understood. We orthotopically injected the pancreas of mice with KPC cells or PBS. One group of tumor-bearing mice was treated with an anti-Ly6G antibody that depletes granulocytic MDSCs and neutrophils; the other received a control antibody. Anti-Ly6G treatment delayed body mass loss, reduced tibialis anterior (TA) muscle wasting, abolished TA muscle fiber atrophy, reduced diaphragm muscle fiber atrophy of type IIb and IIx fibers, and reduced atrophic gene expression in the TA muscles. Anti-ly6G treatment resulted in greater than 50% Ly6G+ cell depletion efficiency in the tumors and TA muscles. These data show that, in the orthotopic KPC model, anti-Ly6G treatment reduces the number of Ly6G+ cells in the tumor and skeletal muscle and reduces skeletal muscle atrophy. These data implicate Ly6G+ cells, including granulocytic MDSCs and neutrophils, as possible contributors to the development of pancreatic cancer-induced skeletal muscle wasting.
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Affiliation(s)
- Michael R. Deyhle
- Department of Physical Therapy, University of Florida, Gainesville, FL 32610, USA; (M.R.D.); (C.S.C.); (D.N.); (A.C.D.); (S.M.J.)
- Department of Health, Exercise & Sports Sciences, University of New Mexico, Albuquerque, NM 87131, USA
| | - Chandler S. Callaway
- Department of Physical Therapy, University of Florida, Gainesville, FL 32610, USA; (M.R.D.); (C.S.C.); (D.N.); (A.C.D.); (S.M.J.)
| | - Daria Neyroud
- Department of Physical Therapy, University of Florida, Gainesville, FL 32610, USA; (M.R.D.); (C.S.C.); (D.N.); (A.C.D.); (S.M.J.)
- Faculty of Biology and Medicine, Institute of Sport Sciences, University of Lausanne, Quartier UNIL-Centre, Building Synathlon, 1015 Lausanne, Switzerland
| | - Andrew C. D’Lugos
- Department of Physical Therapy, University of Florida, Gainesville, FL 32610, USA; (M.R.D.); (C.S.C.); (D.N.); (A.C.D.); (S.M.J.)
| | - Sarah M. Judge
- Department of Physical Therapy, University of Florida, Gainesville, FL 32610, USA; (M.R.D.); (C.S.C.); (D.N.); (A.C.D.); (S.M.J.)
| | - Andrew R. Judge
- Department of Physical Therapy, University of Florida, Gainesville, FL 32610, USA; (M.R.D.); (C.S.C.); (D.N.); (A.C.D.); (S.M.J.)
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Krahl A, Lipphaus A, Sander PM, Witzel U. Determination of muscle strength and function in plesiosaur limbs: finite element structural analyses of Cryptoclidus eurymerus humerus and femur. PeerJ 2022; 10:e13342. [PMID: 35677394 PMCID: PMC9169670 DOI: 10.7717/peerj.13342] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 04/05/2022] [Indexed: 01/13/2023] Open
Abstract
Background The Plesiosauria (Sauropterygia) are secondary marine diapsids. They are the only tetrapods to have evolved hydrofoil fore- and hindflippers. Once this specialization of locomotion had evolved, it remained essentially unchanged for 135 Ma. It is still controversial whether plesiosaurs flew underwater, rowed, or used a mixture of the two modes of locomotion. The long bones of Tetrapoda are functionally loaded by torsion, bending, compression, and tension during locomotion. Superposition of load cases shows that the bones are loaded mainly by compressive stresses. Therefore, it is possible to use finite element structure analysis (FESA) as a test environment for loading hypotheses. These include muscle reconstructions and muscle lines of action (LOA) when the goal is to obtain a homogeneous compressive stress distribution and to minimize bending in the model. Myological reconstruction revealed a muscle-powered flipper twisting mechanism. The flippers of plesiosaurs were twisted along the flipper length axis by extensors and flexors that originated from the humerus and femur as well as further distal locations. Methods To investigate locomotion in plesiosaurs, the humerus and femur of a mounted skeleton of Cryptoclidus eurymerus (Middle Jurassic Oxford Clay Formation from Britain) were analyzed using FE methods based on the concept of optimization of loading by compression. After limb muscle reconstructions including the flipper twisting muscles, LOA were derived for all humerus and femur muscles of Cryptoclidus by stretching cords along casts of the fore- and hindflippers of the mounted skeleton. LOA and muscle attachments were added to meshed volumetric models of the humerus and femur derived from micro-CT scans. Muscle forces were approximated by stochastic iteration and the compressive stress distribution for the two load cases, "downstroke" and "upstroke", for each bone were calculated by aiming at a homogeneous compressive stress distribution. Results Humeral and femoral depressors and retractors, which drive underwater flight rather than rowing, were found to exert higher muscle forces than the elevators and protractors. Furthermore, extensors and flexors exert high muscle forces compared to Cheloniidae. This confirms a convergently evolved myological mechanism of flipper twisting in plesiosaurs and complements hydrodynamic studies that showed flipper twisting is critical for efficient plesiosaur underwater flight.
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Affiliation(s)
- Anna Krahl
- Institute of Geoscience, Section Paleontology, Rheinische Friedrich-Wilhelms Universität Bonn, Bonn, Germany,Biomechanics Research Group, Chair of Product Development, Faculty of Mechanical Engineering, Ruhr-Universität Bochum, Bochum, Germany,Paleontological Collection Fachbereich Geowissenschaften, Eberhard-Karls-Universität Tübingen, Tübingen, Germany
| | - Andreas Lipphaus
- Biomechanics Research Group, Chair of Product Development, Faculty of Mechanical Engineering, Ruhr-Universität Bochum, Bochum, Germany
| | - P. Martin Sander
- Institute of Geoscience, Section Paleontology, Rheinische Friedrich-Wilhelms Universität Bonn, Bonn, Germany
| | - Ulrich Witzel
- Biomechanics Research Group, Chair of Product Development, Faculty of Mechanical Engineering, Ruhr-Universität Bochum, Bochum, Germany
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Pan X, Yue Y, Boftsi M, Wasala LP, Tran NT, Zhang K, Pintel DJ, Tai PWL, Duan D. Rational engineering of a functional CpG-free ITR for AAV gene therapy. Gene Ther 2022; 29:333-345. [PMID: 34611321 PMCID: PMC8983793 DOI: 10.1038/s41434-021-00296-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 09/10/2021] [Accepted: 09/15/2021] [Indexed: 12/12/2022]
Abstract
Inverted terminal repeats (ITRs) are the only wild-type components retained in the genome of adeno-associated virus (AAV) vectors. To determine whether ITR modification is a viable approach for AAV vector engineering, we rationally deleted all CpG motifs in the ITR and examined whether CpG elimination compromises AAV-vector production and transduction. Modified ITRs were stable in the plasmid and maintained the CpG-free nature in purified vectors. Replacing the wild-type ITR with the CpG-free ITR did not affect vector genome encapsidation. However, the vector yield was decreased by approximately 3-fold due to reduced vector genome replication. To study the biological potency, we made micro-dystrophin (μDys) AAV vectors carrying either the wild-type ITR or the CpG-free ITR. We delivered the CpG-free μDys vector to one side of the tibialis anterior muscle of dystrophin-null mdx mice and the wild-type μDys vector to the contralateral side. Evaluation at four months after injection showed no difference in the vector genome copy number, microdystrophin expression, and muscle histology and force. Our results suggest that the complete elimination of the CpG motif in the ITR does not affect the biological activity of the AAV vector. CpG-free ITRs could be useful in engineering therapeutic AAV vectors.
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Affiliation(s)
- Xiufang Pan
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO, 65212, USA
| | - Yongping Yue
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO, 65212, USA
| | - Maria Boftsi
- Pathobiology Area Graduate Program, University of Missouri, Columbia, MO, 65212, USA
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, 65212, USA
| | - Lakmini P Wasala
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO, 65212, USA
- Pathobiology Area Graduate Program, University of Missouri, Columbia, MO, 65212, USA
| | - Ngoc Tam Tran
- Horae Gene Therapy Center, UMass Chan Medical School, Worcester, MA, 01605, USA
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, MA, 01605, USA
| | - Keqing Zhang
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO, 65212, USA
| | - David J Pintel
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO, 65212, USA
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, 65212, USA
| | - Phillip W L Tai
- Horae Gene Therapy Center, UMass Chan Medical School, Worcester, MA, 01605, USA
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, MA, 01605, USA
| | - Dongsheng Duan
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO, 65212, USA.
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, MO, 65212, USA.
- Department of Neurology, School of Medicine, University of Missouri, Columbia, MO, 65212, USA.
- Department of Biomedical, Biological & Chemical Engineering, College of Engineering, University of Missouri, Columbia, MO, 65212, USA.
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Alternative splicing diversifies the skeletal muscle transcriptome during prolonged spaceflight. Skelet Muscle 2022; 12:11. [PMID: 35642060 PMCID: PMC9153194 DOI: 10.1186/s13395-022-00294-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 04/05/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND As the interest in manned spaceflight increases, so does the requirement to understand the transcriptomic mechanisms that underlay the detrimental physiological adaptations of skeletal muscle to microgravity. While microgravity-induced differential gene expression (DGE) has been extensively investigated, the contribution of differential alternative splicing (DAS) to the plasticity and functional status of the skeletal muscle transcriptome has not been studied in an animal model. Therefore, by evaluating both DGE and DAS across spaceflight, we set out to provide the first comprehensive characterization of the transcriptomic landscape of skeletal muscle during exposure to microgravity. METHODS RNA-sequencing, immunohistochemistry, and morphological analyses were conducted utilizing total RNA and tissue sections isolated from the gastrocnemius and quadriceps muscles of 30-week-old female BALB/c mice exposed to microgravity or ground control conditions for 9 weeks. RESULTS In response to microgravity, the skeletal muscle transcriptome was remodeled via both DGE and DAS. Importantly, while DGE showed variable gene network enrichment, DAS was enriched in structural and functional gene networks of skeletal muscle, resulting in the expression of alternatively spliced transcript isoforms that have been associated with the physiological changes to skeletal muscle in microgravity, including muscle atrophy and altered fiber type function. Finally, RNA-binding proteins, which are required for regulation of pre-mRNA splicing, were themselves differentially spliced but not differentially expressed, an upstream event that is speculated to account for the downstream splicing changes identified in target skeletal muscle genes. CONCLUSIONS Our work serves as the first investigation of coordinate changes in DGE and DAS in large limb muscles across spaceflight. It opens up a new opportunity to understand (i) the molecular mechanisms by which splice variants of skeletal muscle genes regulate the physiological adaptations of skeletal muscle to microgravity and (ii) how small molecule splicing regulator therapies might thwart muscle atrophy and alterations to fiber type function during prolonged spaceflight.
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40
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Wasala NB, Million ED, Watkins TB, Wasala LP, Han J, Yue Y, Lu B, Chen SJ, Hakim CH, Duan D. The gRNA Vector Level Determines the Outcome of Systemic AAV CRISPR Therapy for Duchenne Muscular Dystrophy. Hum Gene Ther 2022; 33:518-528. [PMID: 35350865 PMCID: PMC9142771 DOI: 10.1089/hum.2021.130] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 02/13/2022] [Indexed: 01/19/2023] Open
Abstract
Adeno-associated virus (AAV)-mediated clustered regularly interspaced short palindromic repeats (CRISPR) editing holds promise to restore missing dystrophin in Duchenne muscular dystrophy (DMD). Intramuscular coinjection of CRISPR-associated protein 9 (Cas9) and guide RNA (gRNA) vectors resulted in robust dystrophin restoration in short-term studies in the mdx mouse model of DMD. Intriguingly, this strategy failed to yield efficient dystrophin rescue in muscle in a long-term (18-month) systemic injection study. In-depth analyses revealed a selective loss of the gRNA vector after long-term systemic, but not short-term local injection. To determine whether preferential gRNA vector depletion is due to the mode of delivery (local vs. systemic) or the duration of the study (short term vs. long term), we conducted a short-term systemic injection study. The gRNA (4e12 vg/mouse in the 1:1 group or 1.2e13 vg/mouse in the 3:1 group) and Cas9 (4e12 vg/mouse) vectors were coinjected intravenously into 4-week-old mdx mice. The ratio of the gRNA to Cas9 vector genome copy dropped from 1:1 and 3:1 at injection to 0.4:1 and 1:1 at harvest 3 months later, suggesting that the route of administration, rather than the experimental duration, determines preferential gRNA vector loss. Consistent with our long-term systemic injection study, the vector ratio did not influence Cas9 expression. However, the 3:1 group showed significantly higher dystrophin expression and genome editing, better myofiber size distribution, and a more pronounced improvement in muscle function and electrocardiography. Our data suggest that the gRNA vector dose determines the outcome of systemic AAV CRISPR therapy for DMD.
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Affiliation(s)
- Nalinda B. Wasala
- Department of Molecular Microbiology and Immunology, The University of Missouri, Columbia, Missouri, USA
| | - Emily D. Million
- Department of Molecular Microbiology and Immunology, The University of Missouri, Columbia, Missouri, USA
| | - Thais B. Watkins
- Department of Molecular Microbiology and Immunology, The University of Missouri, Columbia, Missouri, USA
| | - Lakmini P. Wasala
- Department of Molecular Microbiology and Immunology, The University of Missouri, Columbia, Missouri, USA
| | - Jin Han
- Department of Molecular Microbiology and Immunology, The University of Missouri, Columbia, Missouri, USA
| | - Yongping Yue
- Department of Molecular Microbiology and Immunology, The University of Missouri, Columbia, Missouri, USA
| | - Baisong Lu
- Wake Forest Institute for Regenerative Medicine, Wake Forest University Health Sciences, Winston-Salem, North Carolina, USA
| | - Shi-jie Chen
- Department of Physics
- Department of Biochemistry, and
- Institute for Data Science and Informatics, The University of Missouri, Columbia, Missouri, USA
| | - Chady H. Hakim
- Department of Molecular Microbiology and Immunology, The University of Missouri, Columbia, Missouri, USA
| | - Dongsheng Duan
- Department of Molecular Microbiology and Immunology, The University of Missouri, Columbia, Missouri, USA
- Departments of Neurology, School of Medicine, The University of Missouri, Columbia, Missouri, USA
- Department of Biomedical, Biological and Chemical Engineering, College of Engineering, The University of Missouri, Columbia, Missouri, USA
- Department of Biomedical Sciences, College of Veterinary Medicine, The University of Missouri, Columbia, Missouri, USA
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41
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Neutrophil and natural killer cell imbalances prevent muscle stem cell-mediated regeneration following murine volumetric muscle loss. Proc Natl Acad Sci U S A 2022; 119:e2111445119. [PMID: 35377804 PMCID: PMC9169656 DOI: 10.1073/pnas.2111445119] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Skeletal muscle is one of the largest tissues in the body and can regenerate when damaged through a population of resident muscle stem cells. A type of muscle trauma called volumetric muscle loss overwhelms the regenerative capacity of muscle stem cells and engenders fibrotic supplantation. A comparison of muscle injuries resulting in regeneration or fibrosis revealed that intercellular communication between neutrophils and natural killer cells impacts muscle stem cell-mediated repair. Perturbation of neutrophil–natural killer cell interactions resulted in a variation of healing outcomes and suggested that immunomodulatory interventions can be effective to prevent aberrant healing outcomes. Volumetric muscle loss (VML) overwhelms the innate regenerative capacity of mammalian skeletal muscle (SkM), leading to numerous disabilities and reduced quality of life. Immune cells are critical responders to muscle injury and guide tissue resident stem cell– and progenitor-mediated myogenic repair. However, how immune cell infiltration and intercellular communication networks with muscle stem cells are altered following VML and drive pathological outcomes remains underexplored. Herein, we contrast the cellular and molecular mechanisms of VML injuries that result in the fibrotic degeneration or regeneration of SkM. Following degenerative VML injuries, we observed the heightened infiltration of natural killer (NK) cells as well as the persistence of neutrophils beyond 2 wk postinjury. Functional validation of NK cells revealed an antagonistic role in neutrophil accumulation in part via inducing apoptosis and CCR1-mediated chemotaxis. The persistent infiltration of neutrophils in degenerative VML injuries was found to contribute to impairments in muscle stem cell regenerative function, which was also attenuated by transforming growth factor beta 1 (TGFβ1). Blocking TGFβ signaling reduced neutrophil accumulation and fibrosis and improved muscle-specific force. Collectively, these results enhance our understanding of immune cell–stem cell cross talk that drives regenerative dysfunction and provide further insight into possible avenues for fibrotic therapy exploration.
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42
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Cieri RL, Dick TJM, Morris JS, Clemente CJ. Scaling of fibre area and fibre glycogen concentration in the hindlimb musculature of monitor lizards: implications for locomotor performance with increasing body size. J Exp Biol 2022; 225:274383. [PMID: 35258618 DOI: 10.1242/jeb.243380] [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: 08/24/2021] [Accepted: 08/26/2021] [Indexed: 12/22/2022]
Abstract
A considerable biomechanical challenge faces larger terrestrial animals as the demands of body support scale with body mass (Mb), while muscle force capacity is proportional to muscle cross-sectional area, which scales with Mb2/3. How muscles adjust to this challenge might be best understood by examining varanids, which vary by five orders of magnitude in size without substantial changes in posture or body proportions. Muscle mass, fascicle length and physiological cross-sectional area all scale with positive allometry, but it remains unclear, however, how muscles become larger in this clade. Do larger varanids have more muscle fibres, or does individual fibre cross-sectional area (fCSA) increase? It is also unknown if larger animals compensate by increasing the proportion of fast-twitch (higher glycogen concentration) fibres, which can produce higher force per unit area than slow-twitch fibres. We investigated muscle fibre area and glycogen concentration in hindlimb muscles from varanids ranging from 105 g to 40,000 g. We found that fCSA increased with modest positive scaling against body mass (Mb0.197) among all our samples, and ∝Mb0.278 among a subset of our data consisting of never-frozen samples only. The proportion of low-glycogen fibres decreased significantly in some muscles but not others. We compared our results with the scaling of fCSA in different groups. Considering species means, fCSA scaled more steeply in invertebrates (∝Mb0.575), fish (∝Mb0.347) and other reptiles (∝Mb0.308) compared with varanids (∝Mb0.267), which had a slightly higher scaling exponent than birds (∝Mb0.134) and mammals (∝Mb0.122). This suggests that, while fCSA generally increases with body size, the extent of this scaling is taxon specific, and may relate to broad differences in locomotor function, metabolism and habitat between different clades.
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Affiliation(s)
- Robert L Cieri
- School of Science and Engineering, University of the Sunshine Coast, Sippy Downs, QLD 4556, Australia
| | - Taylor J M Dick
- School of Science and Engineering, University of the Sunshine Coast, Sippy Downs, QLD 4556, Australia.,School of Biomedical Sciences, University of Queensland, St. Lucia, QLD 4072, Australia
| | - Jeremy S Morris
- Department of Biology, Wofford College, Spartanburg, SC 29303, USA
| | - Christofer J Clemente
- School of Science and Engineering, University of the Sunshine Coast, Sippy Downs, QLD 4556, Australia.,School of Biomedical Sciences, University of Queensland, St. Lucia, QLD 4072, Australia
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43
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Aeles J, Bolsterlee B, Kelp NY, Dick TJM, Hug F. Regional variation in lateral and medial gastrocnemius muscle fibre lengths obtained from diffusion tensor imaging. J Anat 2022; 240:131-144. [PMID: 34411299 PMCID: PMC8655206 DOI: 10.1111/joa.13539] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 08/02/2021] [Accepted: 08/12/2021] [Indexed: 01/16/2023] Open
Abstract
Assessment of regional muscle architecture is primarily done through the study of animals, human cadavers, or using b-mode ultrasound imaging. However, there remain several limitations to how well such measurements represent in vivo human whole muscle architecture. In this study, we developed an approach using diffusion tensor imaging and magnetic resonance imaging to quantify muscle fibre lengths in different muscle regions along a muscle's length and width. We first tested the between-day reliability of regional measurements of fibre lengths in the medial (MG) and lateral gastrocnemius (LG) and found good reliability for these measurements (intraclass correlation coefficient [ICC] = 0.79 and ICC = 0.84, respectively). We then applied this approach to a group of 32 participants including males (n = 18), females (n = 14), young (24 ± 4 years) and older (70 ± 2 years) adults. We assessed the differences in regional muscle fibre lengths between different muscle regions and between individuals. Additionally, we compared regional muscle fibre lengths between sexes, age groups, and muscles. We found substantial variability in fibre lengths between different regions within the same muscle and between the MG and the LG across individuals. At the group level, we found no difference in mean muscle fibre length between males and females, nor between young and older adults, or between the MG and the LG. The high variability in muscle fibre lengths between different regions within the same muscle, possibly expands the functional versatility of the muscle for different task requirements. The high variability between individuals supports the use of subject-specific measurements of muscle fibre lengths when evaluating muscle function.
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Affiliation(s)
- Jeroen Aeles
- Laboratory “Movement, Interactions, Performance” (EA 4334)Nantes UniversityNantesFrance
| | - Bart Bolsterlee
- Neuroscience Research AustraliaSydneyNew South WalesAustralia
- Graduate School of Biomedical EngineeringUniversity of New South WalesSydneyNew South WalesAustralia
| | - Nicole Y. Kelp
- School of Biomedical SciencesThe University of QueenslandBrisbaneQueenslandAustralia
| | - Taylor J. M. Dick
- School of Biomedical SciencesThe University of QueenslandBrisbaneQueenslandAustralia
| | - François Hug
- Laboratory “Movement, Interactions, Performance” (EA 4334)Nantes UniversityNantesFrance
- School of Biomedical SciencesThe University of QueenslandBrisbaneQueenslandAustralia
- Institut Universitaire de France (IUF)ParisFrance
- LAMHESSUniversité Côte d'AzurNiceFrance
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44
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Crislip GR, Johnston JG, Douma LG, Costello HM, Juffre A, Boyd K, Li W, Maugans CC, Gutierrez-Monreal M, Esser KA, Bryant AJ, Liu AC, Gumz ML. Circadian Rhythm Effects on the Molecular Regulation of Physiological Systems. Compr Physiol 2021; 12:2769-2798. [PMID: 34964116 DOI: 10.1002/cphy.c210011] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Nearly every system within the body contains an intrinsic cellular circadian clock. The circadian clock contributes to the regulation of a variety of homeostatic processes in mammals through the regulation of gene expression. Circadian disruption of physiological systems is associated with pathophysiological disorders. Here, we review the current understanding of the molecular mechanisms contributing to the known circadian rhythms in physiological function. This article focuses on what is known in humans, along with discoveries made with cell and rodent models. In particular, the impact of circadian clock components in metabolic, cardiovascular, endocrine, musculoskeletal, immune, and central nervous systems are discussed. © 2021 American Physiological Society. Compr Physiol 11:1-30, 2021.
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Affiliation(s)
- G Ryan Crislip
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida, USA
| | - Jermaine G Johnston
- Department of Medicine, Division of Nephrology, Hypertension, and Renal Transplantation, University of Florida, Gainesville, Florida, USA
| | - Lauren G Douma
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida, USA
| | - Hannah M Costello
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida, USA
| | - Alexandria Juffre
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida, USA
| | - Kyla Boyd
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida, USA
| | - Wendy Li
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida, USA
| | - Cheoting C Maugans
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida, USA
| | - Miguel Gutierrez-Monreal
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida, USA
| | - Karyn A Esser
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida, USA.,Myology Institute, University of Florida, Gainesville, Florida, USA
| | - Andrew J Bryant
- Department of Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine, University of Florida, Gainesville, Florida, USA
| | - Andrew C Liu
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida, USA.,Myology Institute, University of Florida, Gainesville, Florida, USA
| | - Michelle L Gumz
- Department of Medicine, Division of Nephrology, Hypertension, and Renal Transplantation, University of Florida, Gainesville, Florida, USA.,Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida, USA.,Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida, USA.,Center for Integrative Cardiovascular and Metabolic Disease, University of Florida, Gainesville, Florida, USA
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45
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Differential activation of the plantar flexor muscles in balance control across different feet orientations on the ground. J Electromyogr Kinesiol 2021; 62:102625. [PMID: 34911004 DOI: 10.1016/j.jelekin.2021.102625] [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: 08/10/2021] [Revised: 11/17/2021] [Accepted: 12/04/2021] [Indexed: 11/20/2022] Open
Abstract
The ankle plantar flexor muscles act synergistically to control quiet and dynamic body balance. Previous research has shown that the medial (MG) and lateral (LG) gastrocnemii, and soleus (SOL) are differentially activated as a function of motor task requirements. In the present investigation, we evaluated modulation of the plantar flexors' activation from feet orientation on the ground in an upright stance and the ensuing reactive response to a perturbation. A single group of young participants (n = 24) was evaluated in a task requiring initial stabilization of body balance against a backward pulling load (5% or 10% of body weight) attached to their trunk, and then the balance was suddenly perturbed, releasing the load. Four feet orientations were compared: parallel (0°), outward orientation at 15° and 30°, and the preferred orientation (M = 10.5°). Results revealed a higher activation magnitude of SOL compared to MG-LG when sustaining quiet balance against the 10% load. In the generation of reactive responses, MG was characterized by earlier, steeper, and proportionally higher activation than LG-SOL. Feet orientation at 30° led to higher muscular activation than the other orientations, while the activation relationship across muscles was unaffected by feet orientation. Our results support the conclusion of task-specific differential modulation of the plantar flexor muscles for balance control.
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46
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Ormerod KG, Scibelli AE, Littleton JT. Regulation of excitation-contraction coupling at the Drosophila neuromuscular junction. J Physiol 2021; 600:349-372. [PMID: 34788476 DOI: 10.1113/jp282092] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 10/28/2021] [Indexed: 01/05/2023] Open
Abstract
The Drosophila neuromuscular system is widely used to characterize synaptic development and function. However, little is known about how specific synaptic alterations effect neuromuscular transduction and muscle contractility, which ultimately dictate behavioural output. Here we develop and use a force transducer system to characterize excitation-contraction coupling at Drosophila larval neuromuscular junctions (NMJs), examining how specific neuronal and muscle manipulations disrupt muscle contractility. Muscle contraction force increased with motoneuron stimulation frequency and duration, showing considerable plasticity between 5 and 40 Hz and saturating above 50 Hz. Endogenous recordings of fictive contractions revealed average motoneuron burst frequencies of 20-30 Hz, consistent with the system operating within this plastic range of contractility. Temperature was also a key factor in muscle contractility, as force was enhanced at lower temperatures and dramatically reduced with increasing temperatures. Pharmacological and genetic manipulations of critical components of Ca2+ regulation in both pre- and postsynaptic compartments affected the strength and time course of muscle contractions. A screen for modulators of muscle contractility led to identification and characterization of the molecular and cellular pathway by which the FMRFa peptide, TPAEDFMRFa, increases muscle performance. These findings indicate Drosophila NMJs provide a robust system to correlate synaptic dysfunction, regulation and modulation to alterations in excitation-contraction coupling. KEY POINTS: Larval muscle contraction force increases with stimulation frequency and duration, revealing substantial plasticity between 5 and 40 Hz. Fictive contraction recordings demonstrate endogenous motoneuron burst frequencies consistent with the neuromuscular system operating within the range of greatest plasticity. Genetic and pharmacological manipulations of critical components of pre- and postsynaptic Ca2+ regulation significantly affect the strength and time course of muscle contractions. A screen for modulators of the excitation-contraction machinery identified a FMRFa peptide, TPAEDFMRFa and its associated signalling pathway, that dramatically increases muscle performance. Drosophila serves as an excellent model for dissecting components of the excitation-contraction coupling machinery.
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Affiliation(s)
- Kiel G Ormerod
- The Picower Institute for Learning and Memory, Department of Biology, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | | | - J Troy Littleton
- The Picower Institute for Learning and Memory, Department of Biology, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
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47
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Cooper AN, McDermott WJ, Martin JC, Dulaney SO, Carrier DR. Great power comes at a high (locomotor) cost: the role of muscle fascicle length in the power versus economy performance trade-off. J Exp Biol 2021; 224:272355. [PMID: 34605905 DOI: 10.1242/jeb.236679] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 09/27/2021] [Indexed: 11/20/2022]
Abstract
Muscle design constraints preclude simultaneous specialization of the vertebrate locomotor system for explosive and economical force generation. The resulting performance trade-off between power and economy has been attributed primarily to individual differences in muscle fiber type composition. While certainly crucial for performance specialization, fiber type likely interacts with muscle architectural parameters, such as fascicle length, to produce this trade-off. Longer fascicles composed of more serial sarcomeres can achieve faster shortening velocities, allowing for greater power production. Long fascicles likely reduce economy, however, because more energy-consuming contractile units are activated for a given force production. We hypothesized that longer fascicles are associated with both increased power production and locomotor cost. In 11 power-trained and 13 endurance-trained recreational athletes, we measured (1) muscle fascicle length via ultrasound in the gastrocnemius lateralis, gastrocnemius medialis and vastus lateralis, (2) maximal power during cycling and countermovement jumps, and (3) running cost of transport. We estimated muscle fiber type non-invasively based on the pedaling rate at which maximal cycling power occurred. As predicted, longer gastrocnemius muscle fascicles were correlated with greater lower-body power production and cost of transport. Multiple regression analyses revealed that variability in maximal power was explained by fiber type (46% for cycling, 24% for jumping) and average fascicle length (20% for cycling, 13% for jumping), while average fascicle length accounted for 15% of the variation in cost of transport. These results suggest that, at least for certain muscles, fascicle length plays an important role in the power versus economy performance trade-off.
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Affiliation(s)
- Amanda N Cooper
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112, USA
| | - William J McDermott
- Sport Science and Research, The Orthopedic Specialty Hospital, Murray, UT 84107, USA
| | - James C Martin
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT 84112, USA
| | - Shea O Dulaney
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112, USA
| | - David R Carrier
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112, USA
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48
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Abstract
The design of the energy metabolism system in striated muscle remains a major area of investigation. Here, we review our current understanding and emerging hypotheses regarding the metabolic support of muscle contraction. Maintenance of ATP free energy, so called energy homeostasis, via mitochondrial oxidative phosphorylation is critical to sustained contractile activity, and this major design criterion is the focus of this review. Cell volume invested in mitochondria reduces the space available for generating contractile force, and this spatial balance between mitochondria acontractile elements to meet the varying sustained power demands across muscle types is another important design criterion. This is accomplished with remarkably similar mass-specific mitochondrial protein composition across muscle types, implying that it is the organization of mitochondria within the muscle cell that is critical to supporting sustained muscle function. Beyond the production of ATP, ubiquitous distribution of ATPases throughout the muscle requires rapid distribution of potential energy across these large cells. Distribution of potential energy has long been thought to occur primarily through facilitated metabolite diffusion, but recent analysis has questioned the importance of this process under normal physiological conditions. Recent structural and functional studies have supported the hypothesis that the mitochondrial reticulum provides a rapid energy distribution system via the conduction of the mitochondrial membrane potential to maintain metabolic homeostasis during contractile activity. We extensively review this aspect of the energy metabolism design contrasting it with metabolite diffusion models and how mitochondrial structure can play a role in the delivery of energy in the striated muscle.
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Affiliation(s)
- Brian Glancy
- Muscle Energetics Laboratory, National Heart, Lung, and Blood Insititute and National Institute of Arthritis and Musculoskeletal and Skin Disease, Bethesda, Maryland
- Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Insititute, Bethesda, Maryland
| | - Robert S Balaban
- Muscle Energetics Laboratory, National Heart, Lung, and Blood Insititute and National Institute of Arthritis and Musculoskeletal and Skin Disease, Bethesda, Maryland
- Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Insititute, Bethesda, Maryland
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49
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Exercise, but Not Metformin Prevents Loss of Muscle Function Due to Doxorubicin in Mice Using an In Situ Method. Int J Mol Sci 2021; 22:ijms22179163. [PMID: 34502073 PMCID: PMC8430759 DOI: 10.3390/ijms22179163] [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: 07/28/2021] [Revised: 08/22/2021] [Accepted: 08/24/2021] [Indexed: 11/17/2022] Open
Abstract
Though effective in treating various types of cancer, the chemotherapeutic doxorubicin (DOX) is associated with skeletal muscle wasting and fatigue. The purpose of this study was to assess muscle function in situ following DOX administration in mice. Furthermore, pre-treatments with exercise (EX) or metformin (MET) were used in an attempt to preserve muscle function following DOX. Mice were assigned to the following groups: control, DOX, DOX + EX, or DOX + MET, and were given a single injection of DOX (15 mg/kg) or saline 3 days prior to sacrifice. Preceding the DOX injection, DOX + EX mice performed 60 min/day of running for 5 days, while DOX + MET mice received 5 daily oral doses of 500 mg/kg MET. Gastrocnemius–plantaris–soleus complex function was assessed in situ via direct stimulation of the sciatic nerve. DOX treatment increased time to half-relaxation following contractions, indicating impaired recovery (p < 0.05). Interestingly, EX prevented any increase in half-relaxation time, while MET did not. An impaired relaxation rate was associated with a reduction in SERCA1 protein content (p = 0.07) and AMPK phosphorylation (p < 0.05). There were no differences between groups in force production or mitochondrial respiration. These results suggest that EX, but not MET may be an effective strategy for the prevention of muscle fatigue following DOX administration in mice.
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50
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Sahd L, Doubell N, Bennett NC, Kotzé SH. Hind foot drumming: Myosin heavy chain muscle fiber distribution in the hind limb muscles of three African mole-rat species (Bathyergidae). Anat Rec (Hoboken) 2021; 305:170-183. [PMID: 34240567 DOI: 10.1002/ar.24712] [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: 12/22/2020] [Revised: 05/31/2021] [Accepted: 06/07/2021] [Indexed: 11/09/2022]
Abstract
Hind foot drumming as a form of seismic signaling plays a pivotal role in the communication of various mammalian species including Bathyergidae (African mole-rats). The aim of the present study was to histologically determine if the action of hind foot drumming would influence the number of type II fibers present in the hind limb muscles of two drumming (Georychus capensis and Bathyergus suillus) and one non-drumming (Cryptomys hottentotus natalensis) bathyergid species. Twenty-one frozen muscles of each species were selected for the purpose of mid-belly cryostat sections. These sections were immunohistochemically labeled for myosin heavy chain slow muscle fibers (MHCs). In addition, oxidative capacity was determined by means of histochemical staining. A high percentage of fast type II muscle fibers was found in all the functional muscle groups, although there were no statistical differences between the drumming and non-drumming species. Bathyergus suillus had significantly fewer type II fibers in mm. semitendinosus, gluteofemoralis, tibialis cranialis, plantaris, and the medial head of m. gastrocnemius compared to the other two species. In all three species, the majority of the muscle fibers in all functional muscle groups demonstrated low oxidative capacity which correlated with the expression of type II muscle fibers. It therefore seems likely that the number of type II muscle fibers in the hind limb muscles of the Bathyergidae species studied here is more influenced by either body size or digging strategy rather than being an adaptation for hind foot drumming.
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Affiliation(s)
- Lauren Sahd
- Faculty of Medicine and Health Sciences, Division of Clinical Anatomy, Department of Biomedical Sciences, Stellenbosch University, Cape Town, South Africa
| | - Narusa Doubell
- Faculty of Medicine and Health Sciences, Division of Clinical Anatomy, Department of Biomedical Sciences, Stellenbosch University, Cape Town, South Africa
| | - Nigel C Bennett
- Department of Zoology and Entomology, Mammal Research Institute, University of Pretoria, Pretoria, South Africa
| | - Sanet H Kotzé
- Faculty of Medicine and Health Sciences, Division of Clinical Anatomy, Department of Biomedical Sciences, Stellenbosch University, Cape Town, South Africa
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