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Iyer SR, Folker ES, Lovering RM. The Nucleoskeleton: Crossroad of Mechanotransduction in Skeletal Muscle. Front Physiol 2021; 12:724010. [PMID: 34721058 PMCID: PMC8554227 DOI: 10.3389/fphys.2021.724010] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 09/24/2021] [Indexed: 11/13/2022] Open
Abstract
Intermediate filaments (IFs) are a primary structural component of the cytoskeleton extending throughout the muscle cell (myofiber). Mechanotransduction, the process by which mechanical force is translated into a biochemical signal to activate downstream cellular responses, is crucial to myofiber function. Mechanical forces also act on the nuclear cytoskeleton, which is integrated with the myofiber cytoskeleton by the linker of the nucleoskeleton and cytoskeleton (LINC) complexes. Thus, the nucleus serves as the endpoint for the transmission of force through the cell. The nuclear lamina, a dense meshwork of lamin IFs between the nuclear envelope and underlying chromatin, plays a crucial role in responding to mechanical input; myofibers constantly respond to mechanical perturbation via signaling pathways by activation of specific genes. The nucleus is the largest organelle in cells and a master regulator of cell homeostasis, thus an understanding of how it responds to its mechanical environment is of great interest. The importance of the cell nucleus is magnified in skeletal muscle cells due to their syncytial nature and the extreme mechanical environment that muscle contraction creates. In this review, we summarize the bidirectional link between the organization of the nucleoskeleton and the contractile features of skeletal muscle as they relate to muscle function.
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Affiliation(s)
- Shama R Iyer
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Eric S Folker
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Richard M Lovering
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, United States.,Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, United States
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2
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Garcia-Pelagio KP, Bloch RJ. Biomechanical Properties of the Sarcolemma and Costameres of Skeletal Muscle Lacking Desmin. Front Physiol 2021; 12:706806. [PMID: 34489727 PMCID: PMC8416993 DOI: 10.3389/fphys.2021.706806] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Accepted: 07/13/2021] [Indexed: 01/23/2023] Open
Abstract
Intermediate filaments (IFs), composed primarily by desmin and keratins, link the myofibrils to each other, to intracellular organelles, and to the sarcolemma. There they may play an important role in transfer of contractile force from the Z-disks and M-lines of neighboring myofibrils to costameres at the membrane, across the membrane to the extracellular matrix, and ultimately to the tendon (“lateral force transmission”). We measured the elasticity of the sarcolemma and the connections it makes at costameres with the underlying contractile apparatus of individual fast twitch muscle fibers of desmin-null mice. By positioning a suction pipet to the surface of the sarcolemma and applying increasing pressure, we determined the pressure at which the sarcolemma separated from nearby sarcomeres, Pseparation, and the pressure at which the isolated sarcolemma burst, Pbursting. We also examined the time required for the intact sarcolemma-costamere-sarcomere complex to reach equilibrium at lower pressures. All measurements showed the desmin-null fibers to have slower equilibrium times and lower Pseparation and Pbursting than controls, suggesting that the sarcolemma and its costameric links to nearby contractile structures were weaker in the absence of desmin. Comparisons to earlier values determined for muscles lacking dystrophin or synemin suggest that the desmin-null phenotype is more stable than the former and less stable than the latter. Our results are consistent with the moderate myopathy seen in desmin-null muscles and support the idea that desmin contributes significantly to sarcolemmal stability and lateral force transmission.
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Affiliation(s)
- Karla P Garcia-Pelagio
- Departamento de Fisica, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Robert J Bloch
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, United States
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3
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Gould NR, Torre OM, Leser JM, Stains JP. The cytoskeleton and connected elements in bone cell mechano-transduction. Bone 2021; 149:115971. [PMID: 33892173 PMCID: PMC8217329 DOI: 10.1016/j.bone.2021.115971] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/30/2021] [Accepted: 04/17/2021] [Indexed: 02/07/2023]
Abstract
Bone is a mechano-responsive tissue that adapts to changes in its mechanical environment. Increases in strain lead to increased bone mass acquisition, whereas decreases in strain lead to a loss of bone mass. Given that mechanical stress is a regulator of bone mass and quality, it is important to understand how bone cells sense and transduce these mechanical cues into biological changes to identify druggable targets that can be exploited to restore bone cell mechano-sensitivity or to mimic mechanical load. Many studies have identified individual cytoskeletal components - microtubules, actin, and intermediate filaments - as mechano-sensors in bone. However, given the high interconnectedness and interaction between individual cytoskeletal components, and that they can assemble into multiple discreet cellular structures, it is likely that the cytoskeleton as a whole, rather than one specific component, is necessary for proper bone cell mechano-transduction. This review will examine the role of each cytoskeletal element in bone cell mechano-transduction and will present a unified view of how these elements interact and work together to create a mechano-sensor that is necessary to control bone formation following mechanical stress.
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Affiliation(s)
- Nicole R Gould
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Olivia M Torre
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Jenna M Leser
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Joseph P Stains
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA..
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4
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Yuan R, Zhang J, Wang Y, Zhu X, Hu S, Zeng J, Liang F, Tang Q, Chen Y, Chen L, Zhu W, Li M, Mo D. Reorganization of chromatin architecture during prenatal development of porcine skeletal muscle. DNA Res 2021; 28:6261936. [PMID: 34009337 PMCID: PMC8154859 DOI: 10.1093/dnares/dsab003] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 04/26/2021] [Indexed: 11/18/2022] Open
Abstract
Myofibres (primary and secondary myofibre) are the basic structure of muscle and the determinant of muscle mass. To explore the skeletal muscle developmental processes from primary myofibres to secondary myofibres in pigs, we conducted an integrative three-dimensional structure of genome and transcriptomic characterization of longissimus dorsi muscle of pig from primary myofibre formation stage [embryonic Day 35 (E35)] to secondary myofibre formation stage (E80). In the hierarchical genomic structure, we found that 11.43% of genome switched compartment A/B status, 14.53% of topologically associating domains are changed intradomain interactions (D-scores) and 2,730 genes with differential promoter–enhancer interactions and (or) enhancer activity from E35 to E80. The alterations of genome architecture were found to correlate with expression of genes that play significant roles in neuromuscular junction, embryonic morphogenesis, skeletal muscle development or metabolism, typically, NEFL, MuSK, SLN, Mef2D and GCK. Significantly, Sox6 and MATN2 play important roles in the process of primary to secondary myofibres formation and increase the regulatory potential score and genes expression in it. In brief, we reveal the genomic reorganization from E35 to E80 and construct genome-wide high-resolution interaction maps that provide a resource for studying long-range control of gene expression from E35 to E80.
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Affiliation(s)
- Renqiang Yuan
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China.,Institute of Animal Genetics and Breeding, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China
| | - Jiaman Zhang
- Institute of Animal Genetics and Breeding, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China
| | - Yujie Wang
- Institute of Animal Genetics and Breeding, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China
| | - Xingxing Zhu
- Institute of Animal Genetics and Breeding, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China
| | - Silu Hu
- Institute of Animal Genetics and Breeding, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China
| | - Jianhua Zeng
- Guangdong YIHAO Food Co., Ltd, Guangzhou 510620, China
| | - Feng Liang
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Qianzi Tang
- Institute of Animal Genetics and Breeding, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China
| | - Yaosheng Chen
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Luxi Chen
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China.,Guangdong Key Laboratory of Pharmaceutical Bioactive Substances, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Wei Zhu
- Institute of Animal Genetics and Breeding, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China
| | - Mingzhou Li
- Institute of Animal Genetics and Breeding, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China
| | - Delin Mo
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China
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5
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Integrated proteomic and transcriptomic profiling identifies aberrant gene and protein expression in the sarcomere, mitochondrial complex I, and the extracellular matrix in Warmblood horses with myofibrillar myopathy. BMC Genomics 2021; 22:438. [PMID: 34112090 PMCID: PMC8194174 DOI: 10.1186/s12864-021-07758-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 05/26/2021] [Indexed: 02/06/2023] Open
Abstract
Background Myofibrillar myopathy in humans causes protein aggregation, degeneration, and weakness of skeletal muscle. In horses, myofibrillar myopathy is a late-onset disease of unknown origin characterized by poor performance, atrophy, myofibrillar disarray, and desmin aggregation in skeletal muscle. This study evaluated molecular and ultrastructural signatures of myofibrillar myopathy in Warmblood horses through gluteal muscle tandem-mass-tag quantitative proteomics (5 affected, 4 control), mRNA-sequencing (8 affected, 8 control), amalgamated gene ontology analyses, and immunofluorescent and electron microscopy. Results We identified 93/1533 proteins and 47/27,690 genes that were significantly differentially expressed. The top significantly differentially expressed protein CSRP3 and three other differentially expressed proteins, including, PDLIM3, SYNPO2, and SYNPOL2, are integrally involved in Z-disc signaling, gene transcription and subsequently sarcomere integrity. Through immunofluorescent staining, both desmin aggregates and CSRP3 were localized to type 2A fibers. The highest differentially expressed gene CHAC1, whose protein product degrades glutathione, is associated with oxidative stress and apoptosis. Amalgamated transcriptomic and proteomic gene ontology analyses identified 3 enriched cellular locations; the sarcomere (Z-disc & I-band), mitochondrial complex I and the extracellular matrix which corresponded to ultrastructural Z-disc disruption and mitochondrial cristae alterations found with electron microscopy. Conclusions A combined proteomic and transcriptomic analysis highlighted three enriched cellular locations that correspond with MFM ultrastructural pathology in Warmblood horses. Aberrant Z-disc mechano-signaling, impaired Z-disc stability, decreased mitochondrial complex I expression, and a pro-oxidative cellular environment are hypothesized to contribute to the development of myofibrillar myopathy in Warmblood horses. These molecular signatures may provide further insight into diagnostic biomarkers, treatments, and the underlying pathophysiology of MFM. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-07758-0.
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Muniz MMM, Fonseca LFS, Dos Santos Silva DB, de Oliveira HR, Baldi F, Chardulo AL, Ferro JA, Cánovas A, de Albuquerque LG. Identification of novel mRNA isoforms associated with meat tenderness using RNA sequencing data in beef cattle. Meat Sci 2020; 173:108378. [PMID: 33248741 DOI: 10.1016/j.meatsci.2020.108378] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 11/17/2020] [Accepted: 11/18/2020] [Indexed: 12/24/2022]
Abstract
The Warner-Bratzler shear force (WBSF) and myofibrillar fragmentation index (MFI) are complementary methodologies used to measure beef tenderness. Longissimus thoracis samples from the 20 most extreme bulls (out of 80 bulls set) for WBSF (tender (n = 10) and tough (n = 10)) and MFI (high (n = 10) and low (n = 10)) traits were collected to perform transcriptomic analysis using RNA-Sequencing. All analysis were performed through CLC Genomics Workbench. A total of 39 and 27 transcripts for WBSF and MFI phenotypes were DE, respectively. The possible DE novel mRNA isoforms, for WBSF and MFI traits, are myosin encoders (e.g. MYL1 and MYL6). In addition, we identified potential mRNA isoforms related to genes affecting the speed fibers degradation during the meat aging process. The DE novel transcripts are transcripted by genes with biological functions related to oxidative process, energy production and striated muscle contraction. The results suggest that the identified mRNA isoforms could be used as potential candidate to select animals in order to improve meat tenderness.
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Affiliation(s)
- Maria Malane Magalhães Muniz
- School of Agricultural and Veterinarian Sciences, São Paulo State University (Unesp), Jaboticabal, SP, Brazil; Centre for Genetic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, ON, Canada.
| | | | | | - Hinayah Rojas de Oliveira
- Centre for Genetic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, ON, Canada
| | - Fernando Baldi
- School of Agricultural and Veterinarian Sciences, São Paulo State University (Unesp), Jaboticabal, SP, Brazil; National Council for Scientific and Technological Development (CNPq), Brazil
| | - Artur Loyola Chardulo
- National Council for Scientific and Technological Development (CNPq), Brazil; São Paulo State University (Unesp), College of Veterinary and Animal Science, Botucatu, SP, Brazil
| | - Jesus Aparecido Ferro
- School of Agricultural and Veterinarian Sciences, São Paulo State University (Unesp), Jaboticabal, SP, Brazil; National Council for Scientific and Technological Development (CNPq), Brazil
| | - Angela Cánovas
- Centre for Genetic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, ON, Canada
| | - Lucia Galvão de Albuquerque
- School of Agricultural and Veterinarian Sciences, São Paulo State University (Unesp), Jaboticabal, SP, Brazil; National Council for Scientific and Technological Development (CNPq), Brazil.
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7
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Garcia-Pelagio KP, Pratt SJP, Lovering RM. Effects of myofiber isolation technique on sarcolemma biomechanics. Biotechniques 2020; 69:388-391. [PMID: 33000629 PMCID: PMC7686532 DOI: 10.2144/btn-2020-0087] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Isolated myofibers are commonly used to understand the function of skeletal muscle in vivo. This can involve single isolated myofibers obtained from dissection or from enzymatic dissociation. Isolation via dissection allows control of sarcomere length and preserves tendon attachment but is labor-intensive, time-consuming and yields few viable myofibers. In contrast, enzymatic dissociation is fast and facile, produces hundreds of myofibers, and more importantly reduces the number of muscles/animals needed for studies. Biomechanical properties of the sarcolemma have been studied using myofibers from the extensor digitorum longus, but this has been limited to dissected myofibers, making data collection slow and difficult. We have modified this tool to perform biomechanical measurements of the sarcolemma in dissociated myofibers from the flexor digitorum brevis.
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Affiliation(s)
- Karla P Garcia-Pelagio
- Departmento de Física, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Stephen JP Pratt
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Richard M Lovering
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.,Department of Orthopedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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8
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Russell MA. Synemin Redefined: Multiple Binding Partners Results in Multifunctionality. Front Cell Dev Biol 2020; 8:159. [PMID: 32258037 PMCID: PMC7090255 DOI: 10.3389/fcell.2020.00159] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 02/27/2020] [Indexed: 12/15/2022] Open
Abstract
Historically synemin has been studied as an intermediate filament protein. However, synemin also binds the type II regulatory (R) subunit α of protein kinase A (PKA) and protein phosphatase type 2A, thus participating in the PKA and phosphoinositide 3-kinase (PI3K)-Akt and signaling pathways. In addition, recent studies using transgenic mice indicate that a significant function of synemin is its role in signaling pathways in various tissues, including the heart. Recent clinical reports have shown that synemin mutations led to multiple cases of dilated cardiomyopathy. Additionally, a single case of the rare condition ulnar-mammary-like syndrome with left ventricular tachycardia due to a mutation in the synemin gene (SYNM) has been reported. Therefore, this review uses these recent studies to provide a new framework for detailed discussions on synemin tissue distribution, binding partners and synemin in disease. Differences between α- and β-synemin are highlighted. The studies presented here indicate that while synemin does function as an intermediate filament protein, it is unique among this large family of proteins as it is also a regulator of signaling pathways and a crosslinker. Also evident is that the dominant function(s) are isoform-, developmental-, and tissue-specific.
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Affiliation(s)
- Mary A Russell
- Department of Biological Sciences, Kent State University at Trumbull, Warren, OH, United States
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Paulin D, Hovhannisyan Y, Kasakyan S, Agbulut O, Li Z, Xue Z. Synemin-related skeletal and cardiac myopathies: an overview of pathogenic variants. Am J Physiol Cell Physiol 2020; 318:C709-C718. [PMID: 32023076 DOI: 10.1152/ajpcell.00485.2019] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
This review analyzes data concerning patients with cardiomyopathies or skeletal myopathies associated with a variation in the intermediate filament (IF) synemin gene (SYNM), also referred to as desmuslin (DMN). Molecular studies demonstrate that synemin copolymerizes with desmin and vimentin IF and interacts with vinculin, α-actinin, α-dystrobrevin, dystrophin, talin, and zyxin. It has been found that synemin is an A-kinase-anchoring protein (AKAP) that anchors protein kinase A (PKA) and modulates the PKA-dependent phosphorylation of several cytoskeletal substrates such as desmin. Because several IF proteins, including desmin, have been implicated in human genetic disorders such as dominant or recessive congenital and adult-onset myopathy, synemin becomes a significant candidate for cardiac and skeletal myopathies of unknown etiology. Because SYNM is a new candidate gene that displays numerous sequence polymorphisms, in this review, we summarize the genetic and clinical literature about SYNM mutations. Protein-changing variants (missense, frameshifts, nonsense) were further evaluated based on structural modifications and amino acid interactions. We present in silico modeling of helical salt-bridges between residues to evaluate the impact of the synemin networks crucial to interactions with cytoskeletal proteins. Finally, a discussion is featured regarding certain variants that may contribute to the disease state.
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Affiliation(s)
- Denise Paulin
- Sorbonne Université, Institut de Biologie Paris-Seine, CNRS UMR 8256, INSERM ERL U1164, Biological Adaptation and Ageing, Paris, France
| | - Yeranuhi Hovhannisyan
- Sorbonne Université, Institut de Biologie Paris-Seine, CNRS UMR 8256, INSERM ERL U1164, Biological Adaptation and Ageing, Paris, France
| | - Serdar Kasakyan
- Duzen Laboratories Group, Center of Genetic Diagnosis, Istanbul, Turkey
| | - Onnik Agbulut
- Sorbonne Université, Institut de Biologie Paris-Seine, CNRS UMR 8256, INSERM ERL U1164, Biological Adaptation and Ageing, Paris, France
| | - Zhenlin Li
- Sorbonne Université, Institut de Biologie Paris-Seine, CNRS UMR 8256, INSERM ERL U1164, Biological Adaptation and Ageing, Paris, France
| | - Zhigang Xue
- Sorbonne Université, Institut de Biologie Paris-Seine, CNRS UMR 8256, INSERM ERL U1164, Biological Adaptation and Ageing, Paris, France
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Muriel JM, O'Neill A, Kerr JP, Kleinhans-Welte E, Lovering RM, Bloch RJ. Keratin 18 is an integral part of the intermediate filament network in murine skeletal muscle. Am J Physiol Cell Physiol 2019; 318:C215-C224. [PMID: 31721615 DOI: 10.1152/ajpcell.00279.2019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Intermediate filaments (IFs) contribute to force transmission, cellular integrity, and signaling in skeletal muscle. We previously identified keratin 19 (Krt19) as a muscle IF protein. We now report the presence of a second type I muscle keratin, Krt18. Krt18 mRNA levels are about half those for Krt19 and only 1:1,000th those for desmin; the protein was nevertheless detectable in immunoblots. Muscle function, measured by maximal isometric force in vivo, was moderately compromised in Krt18-knockout (Krt18-KO) or dominant-negative mutant mice (Krt18 DN), but structure was unaltered. Exogenous Krt18, introduced by electroporation, was localized in a reticulum around the contractile apparatus in wild-type muscle and to a lesser extent in muscle lacking Krt19 or desmin or both proteins. Exogenous Krt19, which was either reticular or aggregated in controls, became reticular more frequently in Krt19-null than in Krt18-null, desmin-null, or double-null muscles. Desmin was assembled into the reticulum normally in all genotypes. Notably, all three IF proteins appeared in overlapping reticular structures. We assessed the effect of Krt18 on susceptibility to injury in vivo by electroporating siRNA into tibialis anterior (TA) muscles of control and Krt19-KO mice and testing 2 wk later. Results showed a 33% strength deficit (reduction in maximal torque after injury) compared with siRNA-treated controls. Conversely, electroporation of siRNA to Krt19 into Krt18-null TA yielded a strength deficit of 18% after injury compared with controls. Our results suggest that Krt18 plays a complementary role to Krt19 in skeletal muscle in both assembling keratin-based filaments and transducing contractile force.
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Affiliation(s)
- Joaquin M Muriel
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Andrea O'Neill
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Jaclyn P Kerr
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Emily Kleinhans-Welte
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Richard M Lovering
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland
| | - Robert J Bloch
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
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11
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Hughes DC, Marcotte GR, Baehr LM, West DWD, Marshall AG, Ebert SM, Davidyan A, Adams CM, Bodine SC, Baar K. Alterations in the muscle force transfer apparatus in aged rats during unloading and reloading: impact of microRNA-31. J Physiol 2019; 596:2883-2900. [PMID: 29726007 DOI: 10.1113/jp275833] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 03/16/2018] [Indexed: 12/14/2022] Open
Abstract
KEY POINTS Force transfer is integral for maintaining skeletal muscle structure and function. One important component is dystrophin. There is limited understanding of how force transfer is impacted by age and loading. Here, we investigate the force transfer apparatus in muscles of adult and old rats exposed to periods of disuse and reloading. Our results demonstrate an increase in dystrophin protein during the reloading phase in the adult tibialis anterior muscle that is delayed in the old muscle. The consequence of this delay is an increased susceptibility towards contraction-induced muscle injury. Central to the lack of dystrophin protein is an increase in miR-31, a microRNA that inhibits dystrophin translation. In vivo electroporation with a miR-31 sponge led to increased dystrophin protein and decreased contraction-induced muscle injury in old skeletal muscle. Overall, our results detail the importance of the force transfer apparatus and provide new mechanisms for contraction-induced injury in ageing skeletal muscle. ABSTRACT In healthy muscle, the dystrophin-associated glycoprotein complex (DGC), the integrin/focal adhesion complex, intermediate filaments and Z-line proteins transmit force from the contractile proteins to the extracellular matrix. How loading and age affect these proteins is poorly understood. The experiments reported here sought to determine the effect of ageing on the force transfer apparatus following muscle unloading and reloading. Adult (9 months) and old (28 months) rats were subjected to 14 days of hindlimb unloading and 1, 3, 7 and 14 days of reloading. The DGC complex, intermediate filament and Z-line protein and mRNA levels, as well as dystrophin-targeting miRNAs (miR-31, -146b and -374) were examined in the tibialis anterior (TA) and medial gastrocnemius muscles at both ages. There was a significant increase in dystrophin protein levels (2.79-fold) upon 3 days of reloading in the adult TA muscle that did not occur in the old rats (P ≤ 0.05), and the rise in dystrophin protein occurred independent of dystrophin mRNA. The disconnect between dystrophin protein and mRNA levels can partially be explained by age-dependent differences in miR-31. The impaired dystrophin response in aged muscle was followed by an increase in other force transfer proteins (β-dystroglycan, desmuslin and LIM) that was not sufficient to prevent membrane disruption and muscle injury early in the reloading period. Inserting a miR-31 sponge increased dystrophin protein and decreased contraction-induced injury in the TA (P ≤ 0.05). Collectively, these data suggest that increased miR-31 with age contributes to an impaired dystrophin response and increased muscle injury after disuse.
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Affiliation(s)
- David C Hughes
- Department of Neurobiology, Physiology and Behavior, University of California Davis, Davis, CA, USA
| | - George R Marcotte
- Department of Neurobiology, Physiology and Behavior, University of California Davis, Davis, CA, USA
| | - Leslie M Baehr
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA, USA.,VA Northern California Health Care System, Mather, CA, USA
| | - Daniel W D West
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA, USA.,VA Northern California Health Care System, Mather, CA, USA
| | - Andrea G Marshall
- Department of Neurobiology, Physiology and Behavior, University of California Davis, Davis, CA, USA.,Department of Physiology and Membrane Biology, University of California Davis, Davis, CA, USA
| | - Scott M Ebert
- Department of Internal Medicine, University of Iowa, Iowa City, IA, USA.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA, USA.,Iowa City Veterans Affairs Medical Center, Iowa City, IA, USA
| | - Arik Davidyan
- Molecular, Cellular, and Integrative Physiology Graduate Group, University of California Davis, Davis, CA, USA
| | - Christopher M Adams
- Department of Internal Medicine, University of Iowa, Iowa City, IA, USA.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA, USA.,Iowa City Veterans Affairs Medical Center, Iowa City, IA, USA
| | - Sue C Bodine
- Department of Neurobiology, Physiology and Behavior, University of California Davis, Davis, CA, USA.,Department of Physiology and Membrane Biology, University of California Davis, Davis, CA, USA.,VA Northern California Health Care System, Mather, CA, USA
| | - Keith Baar
- Department of Neurobiology, Physiology and Behavior, University of California Davis, Davis, CA, USA.,Department of Physiology and Membrane Biology, University of California Davis, Davis, CA, USA.,VA Northern California Health Care System, Mather, CA, USA
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12
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Klymkowsky MW. Filaments and phenotypes: cellular roles and orphan effects associated with mutations in cytoplasmic intermediate filament proteins. F1000Res 2019; 8. [PMID: 31602295 PMCID: PMC6774051 DOI: 10.12688/f1000research.19950.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/20/2019] [Indexed: 12/11/2022] Open
Abstract
Cytoplasmic intermediate filaments (IFs) surround the nucleus and are often anchored at membrane sites to form effectively transcellular networks. Mutations in IF proteins (IFps) have revealed mechanical roles in epidermis, muscle, liver, and neurons. At the same time, there have been phenotypic surprises, illustrated by the ability to generate viable and fertile mice null for a number of IFp-encoding genes, including vimentin. Yet in humans, the vimentin ( VIM) gene displays a high probability of intolerance to loss-of-function mutations, indicating an essential role. A number of subtle and not so subtle IF-associated phenotypes have been identified, often linked to mechanical or metabolic stresses, some of which have been found to be ameliorated by the over-expression of molecular chaperones, suggesting that such phenotypes arise from what might be termed "orphan" effects as opposed to the absence of the IF network per se, an idea originally suggested by Toivola et al. and Pekny and Lane.
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Affiliation(s)
- Michael W Klymkowsky
- Molecular, Cellular & Developmental Biology, University of Colorado, Boulder, Boulder, CO, 80303, USA
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13
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Swärd K, Krawczyk KK, Morén B, Zhu B, Matic L, Holmberg J, Hedin U, Uvelius B, Stenkula K, Rippe C. Identification of the intermediate filament protein synemin/SYNM as a target of myocardin family coactivators. Am J Physiol Cell Physiol 2019; 317:C1128-C1142. [PMID: 31461342 DOI: 10.1152/ajpcell.00047.2019] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Myocardin (MYOCD) is a critical regulator of smooth muscle cell (SMC) differentiation, but its transcriptional targets remain to be exhaustively characterized, especially at the protein level. Here we leveraged human RNA and protein expression data to identify novel potential MYOCD targets. Using correlation analyses we found several targets that we could confirm at the protein level, including SORBS1, SLMAP, SYNM, and MCAM. We focused on SYNM, which encodes the intermediate filament protein synemin. SYNM rivalled smooth muscle myosin (MYH11) for SMC specificity and was controlled at the mRNA and protein levels by all myocardin-related transcription factors (MRTFs: MYOCD, MRTF-A/MKL1, and MRTF-B/MKL2). MRTF activity is regulated by the ratio of filamentous to globular actin, and SYNM was accordingly reduced by interventions that depolymerize actin, such as latrunculin treatment and overexpression of constitutively active cofilin. Many MRTF target genes depend on serum response factor (SRF), but SYNM lacked SRF-binding motifs in its proximal promoter, which was not directly regulated by MYOCD. Furthermore, SYNM resisted SRF silencing, yet the time course of induction closely paralleled that of the SRF-dependent target gene ACTA2. SYNM was repressed by the ternary complex factor (TCF) FLI1 and was increased in mouse embryonic fibroblasts lacking three classical TCFs (ELK1, ELK3, and ELK4). Imaging showed colocalization of SYNM with the intermediate filament proteins desmin and vimentin, and MRTF-A/MKL1 increased SYNM-containing intermediate filaments in SMCs. These studies identify SYNM as a novel SRF-independent target of myocardin that is abundantly expressed in all SMCs.
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Affiliation(s)
- Karl Swärd
- Department of Experimental Medical Science, Lund, Sweden
| | | | - Björn Morén
- Department of Experimental Medical Science, Lund, Sweden
| | - Baoyi Zhu
- Department of Experimental Medical Science, Lund, Sweden.,Department of Urology, the Sixth Affiliated Hospital of Guangzhou Medical University (Qingyuan People's Hospital), Guangdong, China
| | - Ljubica Matic
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Johan Holmberg
- Department of Experimental Medical Science, Lund, Sweden
| | - Ulf Hedin
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Bengt Uvelius
- Department of Clinical Science, Lund, Lund University, Lund, Sweden
| | - Karin Stenkula
- Department of Experimental Medical Science, Lund, Sweden
| | - Catarina Rippe
- Department of Experimental Medical Science, Lund, Sweden
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14
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Zhang SB, Liu YX, Fan LL, Huang H, Li JJ, Jin JY, Xiang R. A novel heterozygous variant p.(Trp538Arg) of SYNM is identified by whole-exome sequencing in a Chinese family with dilated cardiomyopathy. Ann Hum Genet 2018; 83:95-99. [PMID: 30276801 DOI: 10.1111/ahg.12287] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Revised: 08/13/2018] [Accepted: 08/13/2018] [Indexed: 12/19/2022]
Abstract
Dilated cardiomyopathy (DCM) is a relatively frequent myocardial disease that may lead to heart failure, syncope, and sudden cardiac death. Genetic factors play important roles in the etiology of the disease. To date, at least 50 genes have been identified in patients with DCM, among them, only three mutations have been reported in Synemin (SYNM) gene. In this study, we investigate a Chinese family of three generations with four patients with DCM. Employing whole-exome sequencing (WES) and bioinformatics strategies, a novel heterozygous missense mutation p.(Trp538Arg) of SYNM was identified and cosegregated with the affected family members. The missense mutation locates in the C-terminal domain of SYNM and leads to a substitution of tryptophan by arginine and may cause the structure change of synemin protein. In conclusion, we employed WES to detect the mutations of DCM patients and identified a novel likely pathogenic mutation in SYNM gene. Our study not only expands the spectrum of SYNM mutations, it further confirms that mutations in SYMN may underlie nonfamilial DCM, and offers genetic testing information to additional DCM patients.
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Affiliation(s)
- Shu-Bing Zhang
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha, China
| | - Yu-Xing Liu
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha, China
| | - Liang-Liang Fan
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha, China
| | - Hao Huang
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha, China
| | - Jing-Jing Li
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha, China
| | - Jie-Yuan Jin
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha, China
| | - Rong Xiang
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha, China.,Department of Cardiology, the Second Xiangya Hospital of Central South University, Changsha, China
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15
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Zlotina A, Kiselev A, Sergushichev A, Parmon E, Kostareva A. Rare Case of Ulnar-Mammary-Like Syndrome With Left Ventricular Tachycardia and Lack of TBX3 Mutation. Front Genet 2018; 9:209. [PMID: 29963074 PMCID: PMC6013977 DOI: 10.3389/fgene.2018.00209] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 05/25/2018] [Indexed: 12/13/2022] Open
Abstract
"Heart-hand" type syndromes represent a group of rare congenital conditions that combine cardiac pathology (structural defect or arrhythmic disorder) and limb abnormality. Significant clinical variability and genetic heterogeneity typical for such syndromes complicate correct diagnosis, prognosis, and appropriate genetic counseling of the affected families. By now, only single genes have been unambiguously determined as a genetic cause of heart-hand syndromes and phenotypically similar conditions. In the present study, we report on a 25-year-old Russian female patient with a clinical picture resembling ulnar-mammary syndrome (UMS). Principal clinical manifestations included heart septal fibrosis and non-sustained left ventricular tachycardia combined with fifth finger camptodactyly, hypoplastic breast, abnormal teeth, and mental retardation. Target Sanger sequencing and array-based comparative genome hybridization confirmed the lack of pathogenic mutations and large-scale deletions in TBX3 (12q24.21), the only gene known to be associated with UMS cases to date. Based on the results of whole-exome sequencing, 14 potential candidate variants were identified. Among them, a novel missense variant in SYNM gene (exon 1, c.173C > T, p.A58V), encoding intermediate filament protein synemin was characterized. Until the present, no association between SYNM mutations and congenital clinical syndromes has been reported. At the same time, taking into account synemin tissue-specific expression profiles and available data on abnormal knock-out mice phenotypes, we propose SYNM as a candidate gene contributing to the UMS-like phenotype. Further comprehensive functional studies are required to evaluate possible involvement of SYNM in genesis of complex heart-limb pathology.
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Affiliation(s)
- Anna Zlotina
- Almazov National Medical Research Centre, Saint Petersburg, Russia
| | - Artem Kiselev
- Almazov National Medical Research Centre, Saint Petersburg, Russia
| | | | - Elena Parmon
- Almazov National Medical Research Centre, Saint Petersburg, Russia
| | - Anna Kostareva
- Almazov National Medical Research Centre, Saint Petersburg, Russia
- Department of Women’s and Children’s Health, Center for Molecular Medicine, Karolinska Institute, Solna, Sweden
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16
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García-Pelagio KP, Chen L, Joca HC, Ward C, Jonathan Lederer W, Bloch RJ. Absence of synemin in mice causes structural and functional abnormalities in heart. J Mol Cell Cardiol 2018; 114:354-363. [PMID: 29247678 PMCID: PMC5850968 DOI: 10.1016/j.yjmcc.2017.12.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Revised: 11/22/2017] [Accepted: 12/12/2017] [Indexed: 12/28/2022]
Abstract
Cardiomyopathies have been linked to changes in structural proteins, including intermediate filament (IF) proteins located in the cytoskeleton. IFs associate with the contractile machinery and costameres of striated muscle and with intercalated disks in the heart. Synemin is a large IF protein that mediates the association of desmin with Z-disks and stabilizes intercalated disks. It also acts as an A-kinase anchoring protein (AKAP). In murine skeletal muscle, the absence of synemin causes a mild myopathy. Here, we report that the genetic silencing of synemin in mice (synm -/-) causes left ventricular systolic dysfunction at 3months and 12-16months of age, and left ventricular hypertrophy and dilatation at 12-16months of age. Isolated cardiomyocytes showed alterations in calcium handling that indicate defects intrinsic to the heart. Although contractile and costameric proteins remained unchanged in the old synm -/- hearts, we identified alterations in several signaling proteins (PKA-RII, ERK and p70S6K) critical to cardiomyocyte function. Our data suggest that synemin plays an important regulatory role in the heart and that the consequences of its absence are profound.
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Affiliation(s)
- Karla P García-Pelagio
- Department of Physiology, School of Medicine, University of Maryland, 655 W. Baltimore St., Baltimore, MD 21201, USA; Department of Physics, School of Science, Universidad Nacional Autónoma de México, Av. Universidad 3000, Mexico City 04320, Mexico
| | - Ling Chen
- Department of Physiology, School of Medicine, University of Maryland, 655 W. Baltimore St., Baltimore, MD 21201, USA; Department of Medicine, School of Medicine, University of Maryland, 655 W. Baltimore St., Baltimore, MD 21201, USA
| | - Humberto C Joca
- BioMET, University of Maryland, 111 S Penn St, Baltimore, MD 21201, USA; Department of Biochemistry and Immunology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Av Prof. Alfredo Balena, 190, Belo Horizonte, MG 30130, Brazil
| | - Christopher Ward
- School of Nursing and Department of Orthopedics, School of Medicine, University of Maryland,100 Penn St, Baltimore, MD 21201, USA
| | - W Jonathan Lederer
- Department of Physiology, School of Medicine, University of Maryland, 655 W. Baltimore St., Baltimore, MD 21201, USA; BioMET, University of Maryland, 111 S Penn St, Baltimore, MD 21201, USA
| | - Robert J Bloch
- Department of Physiology, School of Medicine, University of Maryland, 655 W. Baltimore St., Baltimore, MD 21201, USA.
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17
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Zhu C, Song W, Tao Z, Liu H, Xu W, Zhang S, Li H. Deep RNA sequencing of pectoralis muscle transcriptomes during late-term embryonic to neonatal development in indigenous Chinese duck breeds. PLoS One 2017; 12:e0180403. [PMID: 28771592 PMCID: PMC5542427 DOI: 10.1371/journal.pone.0180403] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 06/15/2017] [Indexed: 12/14/2022] Open
Abstract
Pectoral muscle (PM) comprises an important component of overall meat mass in ducks. However, PM has shown arrested or even reduced growth during late embryonic development, and the molecular mechanisms underlying PM growth during the late embryonic to neonatal period in ducks have not been addressed. In this study, we characterized potential candidate genes and signaling pathways related to PM development using RNA sequencing of PM samples selected at embryonic days (E) 21 and 27 and 5 days post-hatch (dph) in two duck breeds (Gaoyou and Jinding ducks). A total of 393 differentially expressed genes (DEGs) were identified, which showed higher or lower expression levels at E27 compared with E21 and 5 dph, reflecting the pattern of PM growth rates. Among these, 43 DEGs were common to all three time points in both duck breeds. These DEGs may thus be involved in regulating this developmental process. Specifically, KEGG pathway analysis of the 393 DEGs showed that genes involved with different metabolism pathways were highly expressed, while genes involved with cell cycle pathways showed lower expression levels at E27. These DEGs may thus be involved in the mechanisms responsible for the phenomenon of static or decreased breast muscle growth in duck breeds during the late embryonic period. These results increase the available genetic information for ducks and provide valuable resources for analyzing the mechanisms underlying the process of PM development.
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Affiliation(s)
- Chunhong Zhu
- Jiangsu Institute of Poultry Science, Yangzhou, Jiangsu Province, People’s Republic of China
| | - Weitao Song
- Jiangsu Institute of Poultry Science, Yangzhou, Jiangsu Province, People’s Republic of China
| | - Zhiyun Tao
- Jiangsu Institute of Poultry Science, Yangzhou, Jiangsu Province, People’s Republic of China
| | - Hongxiang Liu
- Jiangsu Institute of Poultry Science, Yangzhou, Jiangsu Province, People’s Republic of China
| | - Wenjuan Xu
- Jiangsu Institute of Poultry Science, Yangzhou, Jiangsu Province, People’s Republic of China
| | - Shuangjie Zhang
- Jiangsu Institute of Poultry Science, Yangzhou, Jiangsu Province, People’s Republic of China
| | - Huifang Li
- Jiangsu Institute of Poultry Science, Yangzhou, Jiangsu Province, People’s Republic of China
- * E-mail: ,
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18
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Lindqvist J, Torvaldson E, Gullmets J, Karvonen H, Nagy A, Taimen P, Eriksson JE. Nestin contributes to skeletal muscle homeostasis and regeneration. J Cell Sci 2017; 130:2833-2842. [PMID: 28733456 DOI: 10.1242/jcs.202226] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 07/12/2017] [Indexed: 01/15/2023] Open
Abstract
Nestin, a member of the cytoskeletal family of intermediate filaments, regulates the onset of myogenic differentiation through bidirectional signaling with the kinase Cdk5. Here, we show that these effects are also reflected at the organism level, as there is a loss of skeletal muscle mass in nestin-/- (NesKO) mice, reflected as reduced lean (muscle) mass in the mice. Further examination of muscles in male mice revealed that these effects stemmed from nestin-deficient muscles being more prone to spontaneous regeneration. When the regeneration capacity of the compromised NesKO muscle was tested by muscle injury experiments, a significant healing delay was observed. NesKO satellite cells showed delayed proliferation kinetics in conjunction with an elevation in p35 (encoded by Cdk5r1) levels and Cdk5 activity. These results reveal that nestin deficiency generates a spontaneous regenerative phenotype in skeletal muscle that relates to a disturbed proliferation cycle that is associated with uncontrolled Cdk5 activity.
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Affiliation(s)
- Julia Lindqvist
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University, Turku, 20520, Finland.,Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520, Turku, Finland
| | - Elin Torvaldson
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University, Turku, 20520, Finland.,Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520, Turku, Finland
| | - Josef Gullmets
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University, Turku, 20520, Finland.,Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520, Turku, Finland.,Department of Pathology, University of Turku and Turku University Hospital, 20520 Turku, Finland
| | - Henok Karvonen
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University, Turku, 20520, Finland.,Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520, Turku, Finland
| | - Andras Nagy
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, M5G 1X5, Canada
| | - Pekka Taimen
- Department of Pathology, University of Turku and Turku University Hospital, 20520 Turku, Finland
| | - John E Eriksson
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University, Turku, 20520, Finland .,Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520, Turku, Finland
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19
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Hughes DC, Marcotte GR, Marshall AG, West DWD, Baehr LM, Wallace MA, Saleh PM, Bodine SC, Baar K. Age-related Differences in Dystrophin: Impact on Force Transfer Proteins, Membrane Integrity, and Neuromuscular Junction Stability. J Gerontol A Biol Sci Med Sci 2017; 72:640-648. [PMID: 27382038 DOI: 10.1093/gerona/glw109] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 05/27/2016] [Indexed: 11/13/2022] Open
Abstract
The loss of muscle strength with age has been studied from the perspective of a decline in muscle mass and neuromuscular junction (NMJ) stability. A third potential factor is force transmission. The purpose of this study was to determine the changes in the force transfer apparatus within aging muscle and the impact on membrane integrity and NMJ stability. We measured an age-related loss of dystrophin protein that was greatest in the flexor muscles. The loss of dystrophin protein occurred despite a twofold increase in dystrophin mRNA. Importantly, this disparity could be explained by the four- to fivefold upregulation of the dystromir miR-31. To compensate for the loss of dystrophin protein, aged muscle contained increased α-sarcoglycan, syntrophin, sarcospan, laminin, β1-integrin, desmuslin, and the Z-line proteins α-actinin and desmin. In spite of the adaptive increase in other force transfer proteins, over the 48 hours following lengthening contractions, the old muscles showed more signs of impaired membrane integrity (fourfold increase in immunoglobulin G-positive fibers and 70% greater dysferlin mRNA) and NMJ instability (14- to 96-fold increases in Runx1, AchRδ, and myogenin mRNA). Overall, these data suggest that age-dependent alterations in dystrophin leave the muscle membrane and NMJ more susceptible to contraction-induced damage even before changes in muscle mass are obvious.
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Affiliation(s)
| | | | - Andrea G Marshall
- Department of Neurobiology, Physiology and Behavior and.,Department of Physiology and Membrane Biology, University of California, Davis.,VA Northern California Health Care System, Mather
| | - Daniel W D West
- Department of Physiology and Membrane Biology, University of California, Davis.,VA Northern California Health Care System, Mather
| | - Leslie M Baehr
- Department of Physiology and Membrane Biology, University of California, Davis.,VA Northern California Health Care System, Mather
| | | | | | - Sue C Bodine
- Department of Neurobiology, Physiology and Behavior and.,Department of Physiology and Membrane Biology, University of California, Davis.,VA Northern California Health Care System, Mather
| | - Keith Baar
- Department of Neurobiology, Physiology and Behavior and.,Department of Physiology and Membrane Biology, University of California, Davis.,VA Northern California Health Care System, Mather
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20
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21
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Skalli O. The cytoskeleton meets the skeleton. Focus on "Deficiency of the intermediate filament synemin reduces bone mass in vivo". Am J Physiol Cell Physiol 2016; 311:C837-C838. [PMID: 27784680 DOI: 10.1152/ajpcell.00303.2016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Omar Skalli
- Department of Life Sciences, The University of Memphis, Memphis, Tennessee
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22
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Gautel M, Djinović-Carugo K. The sarcomeric cytoskeleton: from molecules to motion. ACTA ACUST UNITED AC 2016; 219:135-45. [PMID: 26792323 DOI: 10.1242/jeb.124941] [Citation(s) in RCA: 143] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Highly ordered organisation of striated muscle is the prerequisite for the fast and unidirectional development of force and motion during heart and skeletal muscle contraction. A group of proteins, summarised as the sarcomeric cytoskeleton, is essential for the ordered assembly of actin and myosin filaments into sarcomeres, by combining architectural, mechanical and signalling functions. This review discusses recent cell biological, biophysical and structural insight into the regulated assembly of sarcomeric cytoskeleton proteins and their roles in dissipating mechanical forces in order to maintain sarcomere integrity during passive extension and active contraction. α-Actinin crosslinks in the Z-disk show a pivot-and-rod structure that anchors both titin and actin filaments. In contrast, the myosin crosslinks formed by myomesin in the M-band are of a ball-and-spring type and may be crucial in providing stable yet elastic connections during active contractions, especially eccentric exercise.
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Affiliation(s)
- Mathias Gautel
- King's College London BHF Centre of Research Excellence, Randall Division for Cell and Molecular Biophysics, and Cardiovascular Division, New Hunt's House, London SE1 1UL, UK
| | - Kristina Djinović-Carugo
- Department of Structural and Computational Biology, Max F. Perutz Laboratories, University of Vienna, Campus Vienna Biocenter 5, Vienna A-1030, Austria Department of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, Ljubljana 1000, Slovenia
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23
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Moorer MC, Buo AM, Garcia-Pelagio KP, Stains JP, Bloch RJ. Deficiency of the intermediate filament synemin reduces bone mass in vivo. Am J Physiol Cell Physiol 2016; 311:C839-C845. [PMID: 27605453 DOI: 10.1152/ajpcell.00218.2016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 09/06/2016] [Indexed: 12/31/2022]
Abstract
While the type IV intermediate filament protein, synemin, has been shown to play a role in striated muscle and neuronal tissue, its presence and function have not been described in skeletal tissue. Here, we report that genetic ablation of synemin in 14-wk-old male mice results in osteopenia that includes a more than 2-fold reduction in the trabecular bone fraction in the distal femur and a reduction in the cross-sectional area at the femoral middiaphysis due to an attendant reduction in both the periosteal and endosteal perimeter. Analysis of serum markers of bone formation and static histomorphometry revealed a statistically significant defect in osteoblast activity and osteoblast number in vivo. Interestingly, primary osteoblasts isolated from synemin-null mice demonstrate markedly enhanced osteogenic capacity with a concomitant reduction in cyclin D1 mRNA expression, which may explain the loss of osteoblast number observed in vivo. In total, these data suggest an important, previously unknown role for synemin in bone physiology.
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Affiliation(s)
- Megan C Moorer
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland; and
| | - Atum M Buo
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland; and
| | - Karla P Garcia-Pelagio
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Joseph P Stains
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland; and
| | - Robert J Bloch
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
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24
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Petrosino JM, Heiss VJ, Maurya SK, Kalyanasundaram A, Periasamy M, LaFountain RA, Wilson JM, Simonetti OP, Ziouzenkova O. Graded Maximal Exercise Testing to Assess Mouse Cardio-Metabolic Phenotypes. PLoS One 2016; 11:e0148010. [PMID: 26859763 PMCID: PMC4747552 DOI: 10.1371/journal.pone.0148010] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 01/12/2016] [Indexed: 12/22/2022] Open
Abstract
Functional assessments of cardiovascular fitness (CVF) are needed to establish animal models of dysfunction, test the effects of novel therapeutics, and establish the cardio-metabolic phenotype of mice. In humans, the graded maximal exercise test (GXT) is a standardized diagnostic for assessing CVF and mortality risk. These tests, which consist of concurrent staged increases in running speed and inclination, provide diagnostic cardio-metabolic parameters, such as, VO2max, anaerobic threshold, and metabolic crossover. Unlike the human-GXT, published mouse treadmill tests have set, not staged, increases in inclination as speed progress until exhaustion (PXT). Additionally, they often lack multiple cardio-metabolic parameters. Here, we developed a mouse-GXT with the intent of improving mouse-exercise testing sensitivity and developing translatable parameters to assess CVF in healthy and dysfunctional mice. The mouse-GXT, like the human-GXT, incorporated staged increases in inclination, speed, and intensity; and, was designed by considering imitations of the PXT and differences between human and mouse physiology. The mouse-GXT and PXTs were both tested in healthy mice (C57BL/6J, FVBN/J) to determine their ability to identify cardio-metabolic parameters (anaerobic threshold, VO2max, metabolic crossover) observed in human-GXTs. Next, theses assays were tested on established diet-induced (obese-C57BL/6J) and genetic (cardiac isoform Casq2-/-) models of cardiovascular dysfunction. Results showed that both tests reported VO2max and provided reproducible data about performance. Only the mouse-GXT reproducibly identified anaerobic threshold, metabolic crossover, and detected impaired CVF in dysfunctional models. Our findings demonstrated that the mouse-GXT is a sensitive, non-invasive, and cost-effective method for assessing CVF in mice. This new test can be used as a functional assessment to determine the cardio-metabolic phenotype of various animal models or the effects of novel therapeutics.
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Affiliation(s)
- Jennifer M. Petrosino
- Department of Human Sciences, The Ohio State University, College of Education & Human Ecology, Columbus, Ohio, United States of America
- Biomedical Sciences Program, The Ohio State University, College of Medicine, Columbus, Ohio, United States of America
| | - Valerie J. Heiss
- Department of Human Sciences, The Ohio State University, College of Education & Human Ecology, Columbus, Ohio, United States of America
| | - Santosh K. Maurya
- Cardiovascular Pathobiology Program, Sanford Burnham Medical Research Institute at Lake Nona, Orland, Florida, United States of America
| | - Anuradha Kalyanasundaram
- Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Columbus, Ohio, United States of America
| | - Muthu Periasamy
- Cardiovascular Pathobiology Program, Sanford Burnham Medical Research Institute at Lake Nona, Orland, Florida, United States of America
| | - Richard A. LaFountain
- Department of Human Sciences, The Ohio State University, College of Education & Human Ecology, Columbus, Ohio, United States of America
| | - Jacob M. Wilson
- Department of Human Performance, The University of Tampa, Tampa, Florida, United States of America
| | - Orlando P. Simonetti
- Department of Radiology, The Ohio State University, College of Medicine, Columbus, Ohio, United States of America
- Department of Cardiovascular Medicine, The Ohio State University, College of Medicine, Columbus, Ohio, United States of America
| | - Ouliana Ziouzenkova
- Department of Human Sciences, The Ohio State University, College of Education & Human Ecology, Columbus, Ohio, United States of America
- * E-mail:
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Perng MD, Huang YS, Quinlan RA. Purification of Protein Chaperones and Their Functional Assays with Intermediate Filaments. Methods Enzymol 2016; 569:155-75. [DOI: 10.1016/bs.mie.2015.07.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Hughes DC, Wallace MA, Baar K. Effects of aging, exercise, and disease on force transfer in skeletal muscle. Am J Physiol Endocrinol Metab 2015; 309:E1-E10. [PMID: 25968577 PMCID: PMC4490334 DOI: 10.1152/ajpendo.00095.2015] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 05/08/2015] [Indexed: 11/22/2022]
Abstract
The loss of muscle strength and increased injury rate in aging skeletal muscle has previously been attributed to loss of muscle protein (cross-sectional area) and/or decreased neural activation. However, it is becoming clear that force transfer within and between fibers plays a significant role in this process as well. Force transfer involves a secondary matrix of proteins that align and transmit the force produced by the thick and thin filaments along muscle fibers and out to the extracellular matrix. These specialized networks of cytoskeletal proteins aid in passing force through the muscle and also serve to protect individual fibers from injury. This review discusses the cytoskeleton proteins that have been identified as playing a role in muscle force transmission, both longitudinally and laterally, and where possible highlights how disease, aging, and exercise influence the expression and function of these proteins.
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Affiliation(s)
- David C Hughes
- Department of Neurobiology, Physiology and Behavior, University of California Davis, Davis, California
| | - Marita A Wallace
- Department of Neurobiology, Physiology and Behavior, University of California Davis, Davis, California
| | - Keith Baar
- Department of Neurobiology, Physiology and Behavior, University of California Davis, Davis, California
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Hernández-Ochoa EO, Pratt SJP, Garcia-Pelagio KP, Schneider MF, Lovering RM. Disruption of action potential and calcium signaling properties in malformed myofibers from dystrophin-deficient mice. Physiol Rep 2015; 3:3/4/e12366. [PMID: 25907787 PMCID: PMC4425971 DOI: 10.14814/phy2.12366] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Duchenne muscular dystrophy (DMD), the most common and severe muscular dystrophy, is caused by the absence of dystrophin. Muscle weakness and fragility (i.e., increased susceptibility to damage) are presumably due to structural instability of the myofiber cytoskeleton, but recent studies suggest that the increased presence of malformed/branched myofibers in dystrophic muscle may also play a role. We have previously studied myofiber morphology in healthy wild-type (WT) and dystrophic (MDX) skeletal muscle. Here, we examined myofiber excitability using high-speed confocal microscopy and the voltage-sensitive indicator di-8-butyl-amino-naphthyl-ethylene-pyridinium-propyl-sulfonate (di-8-ANEPPS) to assess the action potential (AP) properties. We also examined AP-induced Ca2+ transients using high-speed confocal microscopy with rhod-2, and assessed sarcolemma fragility using elastimetry. AP recordings showed an increased width and time to peak in malformed MDX myofibers compared to normal myofibers from both WT and MDX, but no significant change in AP amplitude. Malformed MDX myofibers also exhibited reduced AP-induced Ca2+ transients, with a further Ca2+ transient reduction in the branches of malformed MDX myofibers. Mechanical studies indicated an increased sarcolemma deformability and instability in malformed MDX myofibers. The data suggest that malformed myofibers are functionally different from myofibers with normal morphology. The differences seen in AP properties and Ca2+ signals suggest changes in excitability and remodeling of the global Ca2+ signal, both of which could underlie reported weakness in dystrophic muscle. The biomechanical changes in the sarcolemma support the notion that malformed myofibers are more susceptible to damage. The high prevalence of malformed myofibers in dystrophic muscle may contribute to the progressive strength loss and fragility seen in dystrophic muscles.
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Affiliation(s)
- Erick O Hernández-Ochoa
- Department of Biochemistry & Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Stephen J P Pratt
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland
| | - Karla P Garcia-Pelagio
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Martin F Schneider
- Department of Biochemistry & Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Richard M Lovering
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland
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