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Schultz LE, Colpan M, Smith GE, Mayfield RM, Larrinaga TM, Kostyukova AS, Gregorio CC. A nemaline myopathy-linked mutation inhibits the actin-regulatory functions of tropomodulin and leiomodin. Proc Natl Acad Sci U S A 2023; 120:e2315820120. [PMID: 37956287 PMCID: PMC10665800 DOI: 10.1073/pnas.2315820120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 10/06/2023] [Indexed: 11/15/2023] Open
Abstract
Actin is a highly expressed protein in eukaryotic cells and is essential for numerous cellular processes. In particular, efficient striated muscle contraction is dependent upon the precise regulation of actin-based thin filament structure and function. Alterations in the lengths of actin-thin filaments can lead to the development of myopathies. Leiomodins and tropomodulins are members of an actin-binding protein family that fine-tune thin filament lengths, and their dysfunction is implicated in muscle diseases. An Lmod3 mutation [G326R] was previously identified in patients with nemaline myopathy (NM), a severe skeletal muscle disorder; this residue is conserved among Lmod and Tmod isoforms and resides within their homologous leucine-rich repeat (LRR) domain. We mutated this glycine to arginine in Lmod and Tmod to determine the physiological function of this residue and domain. This G-to-R substitution disrupts Lmod and Tmod's LRR domain structure, altering their binding interface with actin and destroying their abilities to regulate thin filament lengths. Additionally, this mutation renders Lmod3 nonfunctional in vivo. We found that one single amino acid is essential for folding of Lmod and Tmod LRR domains, and thus is essential for the opposing actin-regulatory functions of Lmod (filament elongation) and Tmod (filament shortening), revealing a mechanism underlying the development of NM.
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Affiliation(s)
- Lauren E. Schultz
- Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, AZ85724
| | - Mert Colpan
- Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, AZ85724
| | - Garry E. Smith
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA99164
| | - Rachel M. Mayfield
- Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, AZ85724
| | - Tania M. Larrinaga
- Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, AZ85724
| | - Alla S. Kostyukova
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA99164
| | - Carol C. Gregorio
- Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, AZ85724
- Department of Medicine, Cardiovascular Research Institute, Icahn School of Medicine, New York, NY10029
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2
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Nguyen MT, Dash R, Jeong K, Lee W. Role of Actin-Binding Proteins in Skeletal Myogenesis. Cells 2023; 12:2523. [PMID: 37947600 PMCID: PMC10650911 DOI: 10.3390/cells12212523] [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: 09/28/2023] [Revised: 10/22/2023] [Accepted: 10/23/2023] [Indexed: 11/12/2023] Open
Abstract
Maintenance of skeletal muscle quantity and quality is essential to ensure various vital functions of the body. Muscle homeostasis is regulated by multiple cytoskeletal proteins and myogenic transcriptional programs responding to endogenous and exogenous signals influencing cell structure and function. Since actin is an essential component in cytoskeleton dynamics, actin-binding proteins (ABPs) have been recognized as crucial players in skeletal muscle health and diseases. Hence, dysregulation of ABPs leads to muscle atrophy characterized by loss of mass, strength, quality, and capacity for regeneration. This comprehensive review summarizes the recent studies that have unveiled the role of ABPs in actin cytoskeletal dynamics, with a particular focus on skeletal myogenesis and diseases. This provides insight into the molecular mechanisms that regulate skeletal myogenesis via ABPs as well as research avenues to identify potential therapeutic targets. Moreover, this review explores the implications of non-coding RNAs (ncRNAs) targeting ABPs in skeletal myogenesis and disorders based on recent achievements in ncRNA research. The studies presented here will enhance our understanding of the functional significance of ABPs and mechanotransduction-derived myogenic regulatory mechanisms. Furthermore, revealing how ncRNAs regulate ABPs will allow diverse therapeutic approaches for skeletal muscle disorders to be developed.
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Affiliation(s)
- Mai Thi Nguyen
- Department of Biochemistry, Dongguk University College of Medicine, 123 Dongdae-ro, Gyeongju 38066, Republic of Korea; (M.T.N.); (K.J.)
| | - Raju Dash
- Department of Anatomy, Dongguk University College of Medicine, 123 Dongdae-ro, Gyeongju 38066, Republic of Korea;
- Department of New Biology, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 42988, Republic of Korea
| | - Kyuho Jeong
- Department of Biochemistry, Dongguk University College of Medicine, 123 Dongdae-ro, Gyeongju 38066, Republic of Korea; (M.T.N.); (K.J.)
| | - Wan Lee
- Department of Biochemistry, Dongguk University College of Medicine, 123 Dongdae-ro, Gyeongju 38066, Republic of Korea; (M.T.N.); (K.J.)
- Channelopathy Research Center, Dongguk University College of Medicine, 32 Dongguk-ro, Ilsan Dong-gu, Goyang 10326, Republic of Korea
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3
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Zapater I Morales C, Carman PJ, Soffar DB, Windner SE, Dominguez R, Baylies MK. Drosophila Tropomodulin is required for multiple actin-dependent processes within developing myofibers. Development 2023; 150:dev201194. [PMID: 36806912 PMCID: PMC10112908 DOI: 10.1242/dev.201194] [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: 08/09/2022] [Accepted: 02/09/2023] [Indexed: 02/22/2023]
Abstract
Proper muscle contraction requires the assembly and maintenance of sarcomeres and myofibrils. Although the protein components of myofibrils are generally known, less is known about the mechanisms by which they individually function and together synergize for myofibril assembly and maintenance. For example, it is unclear how the disruption of actin filament (F-actin) regulatory proteins leads to the muscle weakness observed in myopathies. Here, we show that knockdown of Drosophila Tropomodulin (Tmod), results in several myopathy-related phenotypes, including reduction of muscle cell (myofiber) size, increased sarcomere length, disorganization and misorientation of myofibrils, ectopic F-actin accumulation, loss of tension-mediating proteins at the myotendinous junction, and misshaped and internalized nuclei. Our findings support and extend the tension-driven self-organizing myofibrillogenesis model. We show that, like its mammalian counterpart, Drosophila Tmod caps F-actin pointed-ends, and we propose that this activity is crucial for cellular processes in different locations within the myofiber that directly and indirectly contribute to the maintenance of muscle function. Our findings provide significant insights to the role of Tmod in muscle development, maintenance and disease.
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Affiliation(s)
- Carolina Zapater I Morales
- Biochemistry, Cell & Developmental Biology, and Molecular Biology (BCMB) program, Weill Cornell Graduate School of Medical Sciences, New York, NY 10065, USA
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering, Cancer Center, New York, NY 10065, USA
| | - Peter J Carman
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - David B Soffar
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering, Cancer Center, New York, NY 10065, USA
| | - Stefanie E Windner
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering, Cancer Center, New York, NY 10065, USA
| | - Roberto Dominguez
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Mary K Baylies
- Biochemistry, Cell & Developmental Biology, and Molecular Biology (BCMB) program, Weill Cornell Graduate School of Medical Sciences, New York, NY 10065, USA
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering, Cancer Center, New York, NY 10065, USA
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4
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Skrypnyk C, Husain AA, Hassan HY, Ahmed J, Darwish A, Almusalam L, Ben Khalaf N, Al Qashar F. Case report: Homozygous variants of NEB and KLHL40 in two Arab patients with nemaline myopathy. Front Genet 2023; 14:1098102. [PMID: 37025449 PMCID: PMC10070974 DOI: 10.3389/fgene.2023.1098102] [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: 11/14/2022] [Accepted: 02/27/2023] [Indexed: 04/08/2023] Open
Abstract
Objective: Nemaline myopathies are a heterogeneous group of congenital myopathies caused by mutations in different genes associated with the structural and functional proteins of thin muscular filaments. Most patients have congenital onset characterized by hypotonia, respiratory issues, and abnormal deep tendon reflexes, which is a phenotype encountered in a wide spectrum of neuromuscular disorders. Whole-exome sequencing (WES) contributes to a faster diagnosis and facilitates genetic counseling. Methods: Here, we report on two Arab patients from consanguineous families diagnosed with nemaline myopathy of different phenotype spectrum severities. Results: Clinical assessment and particular prenatal history raised suspicion of neuromuscular disease. WES identified homozygous variants in NEB and KLHL40. Muscle biopsy and muscle magnetic resonance imaging studies linked the genetic testing results to the clinical phenotype. The novel variant in the NEB gene resulted in a classical type 2 nemaline myopathy, while the KLHL40 gene variant led to a severe phenotype of nemaline myopathy, type 8. Both patients were identified as having other gene variants with uncertain roles in their complex phenotypes. Conclusions: This study enriches the phenotypic spectrum of nemaline myopathy caused by NEB and KLHL40 variants and highlights the importance of detailed prenatal, neonatal, and infancy assessments of muscular weakness associated with complex systemic features. Variants of uncertain significance in genes associated with nemaline myopathy may be correlated with the phenotype. Early, multidisciplinary intervention can improve the outcome in patients with mild forms of nemaline myopathies. WES is essential for clarifying complex clinical phenotypes encountered in patients from consanguineous families. Targeted carrier screening of extended family members would enable accurate genetic counseling and potential genetic prevention.
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Affiliation(s)
- Cristina Skrypnyk
- Department of Molecular Medicine, Al‐Jawhara Centre for Molecular Medicine, Arabian Gulf University, Manama, Bahrain
- Department of Medical Genetics, University Medical Center, King Abdulla Medical City, Manama, Bahrain
- *Correspondence: Cristina Skrypnyk,
| | - Aseel Ahmed Husain
- Department of Pediatrics, Bahrain Defence Force Hospital, Royal Medical Services, Riffa, Bahrain
| | - Hisham Y. Hassan
- Banoon ART and Cytogenetics Centre, Bahrain Defence Force Hospital, Royal Medical Services, Riffa, Bahrain
| | - Jameel Ahmed
- Radiology Department, University Medical Center, King Abdulla Medical City, Manama, Bahrain
| | - Abdulla Darwish
- Department of Pathology, Bahrain Defence Force Hospital, Royal Medical Services, Riffa, Bahrain
| | - Latifa Almusalam
- Department of Pathology, Bahrain Defence Force Hospital, Royal Medical Services, Riffa, Bahrain
| | - Noureddine Ben Khalaf
- Life Sciences Department, Health Biotechnology Program, College of Graduate Studies, Arabian Gulf University, Manama, Bahrain
| | - Fahad Al Qashar
- Department of Pediatrics, Bahrain Defence Force Hospital, Royal Medical Services, Riffa, Bahrain
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5
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Tolkatchev D, Gregorio CC, Kostyukova AS. The role of leiomodin in actin dynamics: a new road or a secret gate. FEBS J 2022; 289:6119-6131. [PMID: 34273242 PMCID: PMC8761783 DOI: 10.1111/febs.16128] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 05/10/2021] [Accepted: 07/16/2021] [Indexed: 12/29/2022]
Abstract
Leiomodin is an important emerging regulator of thin filaments. As novel molecular, cellular, animal model, and human data accumulate, the mechanisms of its action become clearer. Structural studies played a significant part in understanding the functional significance of leiomodin's interacting partners and functional domains. In this review, we present the current state of knowledge on the structural and cellular properties of leiomodin which has led to two proposed mechanisms of its function. Although it is known that leiomodin is essential for life, numerous domains within leiomodin remain unstudied and as such, we outline future directions for investigations that we predict will provide evidence that leiomodin is a multifunctional protein.
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Affiliation(s)
- Dmitri Tolkatchev
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164, USA
| | - Carol C. Gregorio
- Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, AZ 85724, USA
| | - Alla S. Kostyukova
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164, USA
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6
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Smith GE, Tolkatchev D, Risi C, Little M, Gregorio CC, Galkin VE, Kostyukova AS. Ca 2+ attenuates nucleation activity of leiomodin. Protein Sci 2022; 31:e4358. [PMID: 35762710 PMCID: PMC9207750 DOI: 10.1002/pro.4358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 04/25/2022] [Accepted: 05/14/2022] [Indexed: 11/10/2022]
Abstract
A transient increase in Ca2+ concentration in sarcomeres is essential for their proper function. Ca2+ drives striated muscle contraction via binding to the troponin complex of the thin filament to activate its interaction with the myosin thick filament. In addition to the troponin complex, the myosin essential light chain and myosin-binding protein C were also found to be Ca2+ sensitive. However, the effects of Ca2+ on the function of the tropomodulin family proteins involved in regulating thin filament formation have not yet been studied. Leiomodin, a member of the tropomodulin family, is an actin nucleator and thin filament elongator. Using pyrene-actin polymerization assay and transmission electron microscopy, we show that the actin nucleation activity of leiomodin is attenuated by Ca2+ . Using circular dichroism and nuclear magnetic resonance spectroscopy, we demonstrate that the mostly disordered, negatively charged region of leiomodin located between its first two actin-binding sites binds Ca2+ . We propose that Ca2+ binding to leiomodin results in the attenuation of its nucleation activity. Our data provide further evidence regarding the role of Ca2+ as an ultimate regulator of the ensemble of sarcomeric proteins essential for muscle function. SUMMARY STATEMENT: Ca2+ fluctuations in striated muscle sarcomeres modulate contractile activity via binding to several distinct families of sarcomeric proteins. The effects of Ca2+ on the activity of leiomodin-an actin nucleator and thin filament length regulator-have remained unknown. In this study, we demonstrate that Ca2+ binds directly to leiomodin and attenuates its actin nucleating activity. Our data emphasizes the ultimate role of Ca2+ in the regulation of the sarcomeric protein interactions.
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Affiliation(s)
- Garry E. Smith
- Voiland School of Chemical Engineering and BioengineeringWashington State UniversityPullmanWashingtonUSA
| | - Dmitri Tolkatchev
- Voiland School of Chemical Engineering and BioengineeringWashington State UniversityPullmanWashingtonUSA
| | - Cristina Risi
- Department of Physiological SciencesEastern Virginia Medical SchoolNorfolkVirginiaUSA
| | - Madison Little
- Voiland School of Chemical Engineering and BioengineeringWashington State UniversityPullmanWashingtonUSA
| | - Carol C. Gregorio
- Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research ProgramUniversity of ArizonaTucsonArizonaUSA
| | - Vitold E. Galkin
- Department of Physiological SciencesEastern Virginia Medical SchoolNorfolkVirginiaUSA
| | - Alla S. Kostyukova
- Voiland School of Chemical Engineering and BioengineeringWashington State UniversityPullmanWashingtonUSA
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7
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The Mechanisms of Thin Filament Assembly and Length Regulation in Muscles. Int J Mol Sci 2022; 23:ijms23105306. [PMID: 35628117 PMCID: PMC9140763 DOI: 10.3390/ijms23105306] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 05/05/2022] [Accepted: 05/06/2022] [Indexed: 02/01/2023] Open
Abstract
The actin containing tropomyosin and troponin decorated thin filaments form one of the crucial components of the contractile apparatus in muscles. The thin filaments are organized into densely packed lattices interdigitated with myosin-based thick filaments. The crossbridge interactions between these myofilaments drive muscle contraction, and the degree of myofilament overlap is a key factor of contractile force determination. As such, the optimal length of the thin filaments is critical for efficient activity, therefore, this parameter is precisely controlled according to the workload of a given muscle. Thin filament length is thought to be regulated by two major, but only partially understood mechanisms: it is set by (i) factors that mediate the assembly of filaments from monomers and catalyze their elongation, and (ii) by factors that specify their length and uniformity. Mutations affecting these factors can alter the length of thin filaments, and in human cases, many of them are linked to debilitating diseases such as nemaline myopathy and dilated cardiomyopathy.
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8
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Yuen M, Worgan L, Iwanski J, Pappas CT, Joshi H, Churko JM, Arbuckle S, Kirk EP, Zhu Y, Roscioli T, Gregorio CC, Cooper ST. Neonatal-lethal dilated cardiomyopathy due to a homozygous LMOD2 donor splice-site variant. Eur J Hum Genet 2022; 30:450-457. [PMID: 35082396 PMCID: PMC8989920 DOI: 10.1038/s41431-022-01043-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 12/23/2021] [Accepted: 01/07/2022] [Indexed: 12/29/2022] Open
Abstract
Dilated cardiomyopathy (DCM) is characterized by cardiac enlargement and impaired ventricular contractility leading to heart failure. A single report identified variants in leiomodin-2 (LMOD2) as a cause of neonatally-lethal DCM. Here, we describe two siblings with DCM who died shortly after birth due to heart failure. Exome sequencing identified a homozygous LMOD2 variant in both siblings, (GRCh38)chr7:g.123656237G > A; NM_207163.2:c.273 + 1G > A, ablating the donor 5' splice-site of intron-1. Pre-mRNA splicing studies and western blot analysis on cDNA derived from proband cardiac tissue, MyoD-transduced proband skin fibroblasts and HEK293 cells transfected with LMOD2 gene constructs established variant-associated absence of canonically spliced LMOD2 mRNA and full-length LMOD2 protein. Immunostaining of proband heart tissue unveiled abnormally short actin-thin filaments. Our data are consistent with LMOD2 c.273 + 1G > A abolishing/reducing LMOD2 transcript expression by: (1) variant-associated perturbation in initiation of transcription due to ablation of the intron-1 donor; and/or (2) degradation of aberrant LMOD2 transcripts (resulting from use of alternative transcription start-sites or cryptic splice-sites) by nonsense-mediated decay. LMOD2 expression is critical for life and the absence of LMOD2 is associated with thin filament shortening and severe cardiac contractile dysfunction. This study describes the first splice-site variant in LMOD2 and confirms the role of LMOD2 variants in DCM.
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Affiliation(s)
- Michaela Yuen
- Kids Neuroscience Centre, The Children's Hospital at Westmead, Westmead, NSW, Australia.
- Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, Camperdown, NSW, Australia.
| | - Lisa Worgan
- Department of Medical Genomics, Royal Prince Alfred Hospital, Camperdown, NSW, Australia
| | - Jessika Iwanski
- Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, AZ, USA
| | - Christopher T Pappas
- Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, AZ, USA
| | - Himanshu Joshi
- Kids Neuroscience Centre, The Children's Hospital at Westmead, Westmead, NSW, Australia
| | - Jared M Churko
- Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, AZ, USA
| | - Susan Arbuckle
- Department of Histopathology, The Children's Hospital at Westmead, Westmead, NSW, Australia
| | - Edwin P Kirk
- New South Wales Health Pathology, Randwick Genomics Laboratory, Randwick, NSW, Australia
- School of Women's and Children's Health, University of New South Wales, Randwick, NSW, Australia
- Centre for Clinical Genetics, Sydney Children's Hospital, Randwick, NSW, Australia
| | - Ying Zhu
- New South Wales Health Pathology, Randwick Genomics Laboratory, Randwick, NSW, Australia
| | - Tony Roscioli
- New South Wales Health Pathology, Randwick Genomics Laboratory, Randwick, NSW, Australia
- Centre for Clinical Genetics, Sydney Children's Hospital, Randwick, NSW, Australia
- Neuroscience Research Australia (NeuRA), University of New South Wales, Sydney, NSW, Australia
| | - Carol C Gregorio
- Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, AZ, USA
| | - Sandra T Cooper
- Kids Neuroscience Centre, The Children's Hospital at Westmead, Westmead, NSW, Australia
- Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, Camperdown, NSW, Australia
- The Children's Medical Research Institute, Westmead, NSW, Australia
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9
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Berger J, Berger S, Mok YSG, Li M, Tarakci H, Currie PD. Genetic dissection of novel myopathy models reveals a role of CapZα and Leiomodin 3 during myofibril elongation. PLoS Genet 2022; 18:e1010066. [PMID: 35148320 PMCID: PMC8870547 DOI: 10.1371/journal.pgen.1010066] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 02/24/2022] [Accepted: 02/01/2022] [Indexed: 12/18/2022] Open
Abstract
Myofibrils within skeletal muscle are composed of sarcomeres that generate force by contraction when their myosin-rich thick filaments slide past actin-based thin filaments. Although mutations in components of the sarcomere are a major cause of human disease, the highly complex process of sarcomere assembly is not fully understood. Current models of thin filament assembly highlight a central role for filament capping proteins, which can be divided into three protein families, each ascribed with separate roles in thin filament assembly. CapZ proteins have been shown to bind the Z-disc protein α-actinin to form an anchoring complex for thin filaments and actin polymerisation. Subsequent thin filaments extension dynamics are thought to be facilitated by Leiomodins (Lmods) and thin filament assembly is concluded by Tropomodulins (Tmods) that specifically cap the pointed end of thin filaments. To study thin filament assembly in vivo, single and compound loss-of-function zebrafish mutants within distinct classes of capping proteins were analysed. The generated lmod3- and capza1b-deficient zebrafish exhibited aspects of the pathology caused by variations in their human orthologs. Although loss of the analysed main capping proteins of the skeletal muscle, capza1b, capza1a, lmod3 and tmod4, resulted in sarcomere defects, residual organised sarcomeres were formed within the assessed mutants, indicating that these proteins are not essential for the initial myofibril assembly. Furthermore, detected similarity and location of myofibril defects, apparent at the peripheral ends of myofibres of both Lmod3- and CapZα-deficient mutants, suggest a function in longitudinal myofibril growth for both proteins, which is molecularly distinct to the function of Tmod4. The force-generating contractile apparatus is a highly organised structure mainly composed of thick and thin filaments of uniform length. Three families of capping proteins are described to play a role in the regulation of thin filament length. Current models suggest that thin filament assembly is initiated by CapZ, extended by Leiomodins (Lmods) and concluded by Tropomodulins (Tmods). To better understand the role of these capping proteins, we analysed single and double loss-of-function zebrafish mutants for these capping proteins. We find that lmod3- and capza1b-deficient zebrafish model aspects of the human disorders caused by variations in their orthologs. Surprisingly, although pivotal for sarcomere formation, our results reveal that none of the analysed capping proteins, capza1b, capza1a, lmod3 and tmod4, are absolutely required for thin filament assembly, as suggested by current models. Our study further indicates that the roles of CapZ and Lmod3 are distinct from Tmod4. Both Lmod3- as well as CapZα-deficient mutants feature specific defects at the peripheral ends of muscle cells. We conclude that, in addition to their non-essential role during thin filament assembly, both Lmod3- and CapZα proteins may function in the longitudinal growth of the contractile apparatus.
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Affiliation(s)
- Joachim Berger
- Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
- Victoria Node, EMBL Australia, Clayton, Australia
- * E-mail: (JB); (PDC)
| | - Silke Berger
- Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
- Victoria Node, EMBL Australia, Clayton, Australia
| | - Yu Shan G. Mok
- Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
- Victoria Node, EMBL Australia, Clayton, Australia
| | - Mei Li
- Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
- Victoria Node, EMBL Australia, Clayton, Australia
| | - Hakan Tarakci
- Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
- Victoria Node, EMBL Australia, Clayton, Australia
| | - Peter D. Currie
- Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
- Victoria Node, EMBL Australia, Clayton, Australia
- * E-mail: (JB); (PDC)
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10
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Delhase M. Identification of genes differentially expressed between a somatotrope and a lactotrope pituitary cell lines by representational difference analysis. ENDOCRINE AND METABOLIC SCIENCE 2021. [DOI: 10.1016/j.endmts.2021.100107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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11
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Song R, Zhao S, Xu Y, Hu J, Ke S, Li F, Tian G, Zheng X, Li J, Gu L, Xu Y. MRTF-A regulates myoblast commitment to differentiation by targeting PAX7 during muscle regeneration. J Cell Mol Med 2021; 25:8645-8661. [PMID: 34347392 PMCID: PMC8435411 DOI: 10.1111/jcmm.16820] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 07/11/2021] [Accepted: 07/13/2021] [Indexed: 12/14/2022] Open
Abstract
Myocardin-related transcription factor-A/serum response factor (MRTF-A/SRF), a well-known transcriptional programme, has been proposed to play crucial roles in skeletal muscle development and function. However, whether MRTF-A participates in muscle regeneration and the molecular mechanisms are not completely understood. Here, we show that MRTF-A levels are highly correlated with myogenic genes using a RNA-seq assay, which reveal that MRTF-A knockdown in C2C12 cells significantly reduces PAX7 expression. Subsequent in vitro and in vivo data show that MRTF-A and PAX7 present identical expression patterns during myoblast differentiation and CTX-induced muscle injury and repair. Remarkably, MRTF-A overexpression promotes myoblast proliferation, while inhibiting cell differentiation and the expression of MyoD and MyoG. MRTF-A loss of function produces the opposite effect. Moreover, mice with lentivirus (MRTF-A) injection possesses more PAX7+ satellite cells, but less differentiating MyoD+ and MyoG+ cells, leading subsequently to diminished muscle regeneration. Our mechanistic results reveal that MRTF-A contributes to PAX7-mediated myoblast self-renewal, proliferation, and differentiation by binding to its distal CArG box. Overall, we propose that MRTF-A functions as a novel PAX7 regulator upon myoblast commitment to differentiation, which could provide pathways for dictating muscle stem cell fate and open new avenues to explore stem cell-based therapy for muscle degenerative diseases.
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Affiliation(s)
- Ruhui Song
- Institute of Biology and Medicine, College of Life Science and Health, Wuhan University of Science and Technology, Wuhan, Hubei, 430081, China
| | - Shengnan Zhao
- Institute of Biology and Medicine, College of Life Science and Health, Wuhan University of Science and Technology, Wuhan, Hubei, 430081, China
| | - Yue Xu
- Institute of Biology and Medicine, College of Life Science and Health, Wuhan University of Science and Technology, Wuhan, Hubei, 430081, China
| | - Jian Hu
- Animal Disease Control and Prevention Centre of Chongqing City, Chongqing, 401120, China
| | - Shuangao Ke
- Institute of Biology and Medicine, College of Life Science and Health, Wuhan University of Science and Technology, Wuhan, Hubei, 430081, China
| | - Fan Li
- Institute of Biology and Medicine, College of Life Science and Health, Wuhan University of Science and Technology, Wuhan, Hubei, 430081, China
| | - Gaohui Tian
- Institute of Biology and Medicine, College of Life Science and Health, Wuhan University of Science and Technology, Wuhan, Hubei, 430081, China
| | - Xiao Zheng
- Institute of Biology and Medicine, College of Life Science and Health, Wuhan University of Science and Technology, Wuhan, Hubei, 430081, China
| | - Jiajun Li
- Institute of Biology and Medicine, College of Life Science and Health, Wuhan University of Science and Technology, Wuhan, Hubei, 430081, China
| | - Lixing Gu
- Institute of Biology and Medicine, College of Life Science and Health, Wuhan University of Science and Technology, Wuhan, Hubei, 430081, China
| | - Yao Xu
- Institute of Biology and Medicine, College of Life Science and Health, Wuhan University of Science and Technology, Wuhan, Hubei, 430081, China
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12
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Lmod3 promotes myoblast differentiation and proliferation via the AKT and ERK pathways. Exp Cell Res 2020; 396:112297. [DOI: 10.1016/j.yexcr.2020.112297] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 09/17/2020] [Accepted: 09/19/2020] [Indexed: 12/29/2022]
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13
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Ward M, Iskratsch T. Mix and (mis-)match - The mechanosensing machinery in the changing environment of the developing, healthy adult and diseased heart. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2020; 1867:118436. [PMID: 30742931 PMCID: PMC7042712 DOI: 10.1016/j.bbamcr.2019.01.017] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 01/07/2019] [Accepted: 01/29/2019] [Indexed: 01/01/2023]
Abstract
The composition and the stiffness of cardiac microenvironment change during development and/or in heart disease. Cardiomyocytes (CMs) and their progenitors sense these changes, which decides over the cell fate and can trigger CM (progenitor) proliferation, differentiation, de-differentiation or death. The field of mechanobiology has seen a constant increase in output that also includes a wealth of new studies specific to cardiac or cardiomyocyte mechanosensing. As a result, mechanosensing and transduction in the heart is increasingly being recognised as a main driver of regulating the heart formation and function. Recent work has for instance focused on measuring the molecular, physical and mechanical changes of the cellular environment - as well as intracellular contributors to the passive stiffness of the heart. On the other hand, a variety of new studies shed light into the molecular machinery that allow the cardiomyocytes to sense these properties. Here we want to discuss the recent work on this topic, but also specifically focus on how the different components are regulated at various stages during development, in health or disease in order to highlight changes that might contribute to disease progression and heart failure.
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Key Words
- cm, cardiomyocytes
- hcm, hypertrophic cardiomyopathy
- dcm, dilated cardiomyopathy
- icm, idiopathic cardiomyopathy
- myh, myosin heavy chain
- tnnt, troponin t
- tnni, troponin i
- afm, atomic force microscope
- mre, magnetic resonance elastography
- swe, ultrasound cardiac shear-wave elastography
- lv, left ventricle
- lox, lysyl oxidase
- loxl, lysyl oxidase like protein
- lh, lysyl hydroxylase
- lys, lysin
- lccs, lysald-derived collagen crosslinks
- hlccs, hylald-derived collagen crosslinks
- pka, protein kinase a
- pkc, protein kinase c
- vash1, vasohibin-1
- svbp, small vasohibin binding protein
- tcp, tubulin carboxypeptidase
- ttl, tubulin tyrosine ligase
- mrtf, myocardin-related transcription factor
- gap, gtpase activating protein
- gef, guanine nucleotide exchange factor
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Affiliation(s)
- Matthew Ward
- Division of Bioengineering, School of Engineering and Materials Science & Institute for Bioengineering, Queen Mary University of London, United Kingdom
| | - Thomas Iskratsch
- Division of Bioengineering, School of Engineering and Materials Science & Institute for Bioengineering, Queen Mary University of London, United Kingdom.
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14
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Mi-Mi L, Farman GP, Mayfield RM, Strom J, Chu M, Pappas CT, Gregorio CC. In vivo elongation of thin filaments results in heart failure. PLoS One 2020; 15:e0226138. [PMID: 31899774 PMCID: PMC6941805 DOI: 10.1371/journal.pone.0226138] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Accepted: 11/20/2019] [Indexed: 12/20/2022] Open
Abstract
A novel cardiac-specific transgenic mouse model was generated to identify the physiological consequences of elongated thin filaments during post-natal development in the heart. Remarkably, increasing the expression levels in vivo of just one sarcomeric protein, Lmod2, results in ~10% longer thin filaments (up to 26% longer in some individual sarcomeres) that produce up to 50% less contractile force. Increasing the levels of Lmod2 in vivo (Lmod2-TG) also allows us to probe the contribution of Lmod2 in the progression of cardiac myopathy because Lmod2-TG mice present with a unique cardiomyopathy involving enlarged atrial and ventricular lumens, increased heart mass, disorganized myofibrils and eventually, heart failure. Turning off of Lmod2 transgene expression at postnatal day 3 successfully prevents thin filament elongation, as well as gross morphological and functional disease progression. We show here that Lmod2 has an essential role in regulating cardiac contractile force and function.
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Affiliation(s)
- Lei Mi-Mi
- Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, AZ, United States of America
| | - Gerrie P. Farman
- Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, AZ, United States of America
| | - Rachel M. Mayfield
- Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, AZ, United States of America
| | - Joshua Strom
- Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, AZ, United States of America
| | - Miensheng Chu
- Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, AZ, United States of America
| | - Christopher T. Pappas
- Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, AZ, United States of America
| | - Carol C. Gregorio
- Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, AZ, United States of America
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15
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Marguet F, Rendu J, Vanhulle C, Bedat-Millet AL, Brehin AC, Fauré J, Laquerrière A. Association of fingerprint bodies with rods in a case with mutations in the LMOD3 gene. Neuromuscul Disord 2019; 30:207-212. [PMID: 32008911 DOI: 10.1016/j.nmd.2019.12.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 12/09/2019] [Accepted: 12/16/2019] [Indexed: 12/19/2022]
Abstract
Fingerprint bodies are observed in a variety of clinical situations with no definite genetic cause identified so far. We report for the first time the association of fingerprint bodies with rods in a patient who developed a slowly progressive myopathy affecting the face and limb extremities. Ultrastructural examination first disclosed fingerprint bodies and on a second biopsy, associated cytoplasmic bodies and rods. Next Generation Sequencing panel of congenital nemaline myopathy genes allowed the identification of two novel variants, a deleterious missense variant (c.1628G>T, p.Arg543Leu) located in the WASP-homology 2 domain, and a deletion (c.366delG, p.Lys122AsnFs*6) in the LMOD3 gene, generally causing severe nemaline myopathy with antenatal onset and early death. Recently, a less severe phenotype similar to our case has been reported. Our study confirms the existence of milder phenotypes linked to LMOD3 mutations and underlines that fingerprint bodies, though not specific, may be an early ultrastructural marker that could be linked, among others, to nemaline myopathy.
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Affiliation(s)
- Florent Marguet
- Department of Pathology, Normandie University, UNIROUEN, INSERM U1245, Rouen University Hospital, F76000 Rouen, France
| | - John Rendu
- Grenoble Institut Neurosciences, University of Grenoble Alpes, Inserm, U1216, CHU Grenoble Alpes, 38000 Grenoble, France
| | - Catherine Vanhulle
- Department of Neonatal Pediatrics and Intensive Care, Rouen University Hospital, F76000 Rouen, France
| | | | - Anne Claire Brehin
- Department of Medical Genetics, Rouen University Hospital, F76000 Rouen, France
| | - Julien Fauré
- Grenoble Institut Neurosciences, University of Grenoble Alpes, Inserm, U1216, CHU Grenoble Alpes, 38000 Grenoble, France
| | - Annie Laquerrière
- Department of Pathology, Normandie University, UNIROUEN, INSERM U1245, Rouen University Hospital, F76000 Rouen, France.
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16
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Bordbar F, Jensen J, Zhu B, Wang Z, Xu L, Chang T, Xu L, Du M, Zhang L, Gao H, Xu L, Li J. Identification of muscle-specific candidate genes in Simmental beef cattle using imputed next generation sequencing. PLoS One 2019; 14:e0223671. [PMID: 31600309 PMCID: PMC6786524 DOI: 10.1371/journal.pone.0223671] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 09/25/2019] [Indexed: 01/01/2023] Open
Abstract
Genome-wide association studies (GWAS) have commonly been used to identify candidate genes that control economically important traits in livestock. Our objective was to detect potential candidate genes associated mainly with muscle development traits related to dimension of hindquarter in cattle. A next generation sequencing (NGS) dataset to imputed to 12 million single nucleotide polymorphisms (SNPs) (from 1252 Simmental beef cattle) were used to search for genes affecting hindquarter traits using a linear, mixed model approach. We also used haplotype and linkage disequilibrium blocks to further support our identifications. We identified 202 significant SNPs in the bovine BTA4 chromosome region associated with width of hind leg, based on a stringent statistical threshold (p = 0.05/ effective number of SNPs identified). After exploring the region around these SNPs, we found candidate genes that were potentially related to the associated markers. More importantly, we identified a region of approximately 280 Kb on the BTA4 chromosome that harbored several muscle specific candidate genes, genes to be in a potential region for muscle development. However, we also found candidate gene SLC13A1 on BTA4, which seems to be associated with bone disorders (such as chondrodysplasia) in Simmental beef cattle.
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Affiliation(s)
- Farhad Bordbar
- Laboratory of Molecular Biology and Bovine Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Just Jensen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Bo Zhu
- Laboratory of Molecular Biology and Bovine Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Zezhao Wang
- Laboratory of Molecular Biology and Bovine Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Lei Xu
- Laboratory of Molecular Biology and Bovine Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Tianpeng Chang
- Laboratory of Molecular Biology and Bovine Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Ling Xu
- Laboratory of Molecular Biology and Bovine Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Min Du
- Department of Animal Sciences, Washington Center for Muscle Biology, Washington State University, Pullman, Washington, United States of America
| | - Lupei Zhang
- Laboratory of Molecular Biology and Bovine Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Huijiang Gao
- Laboratory of Molecular Biology and Bovine Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Lingyang Xu
- Laboratory of Molecular Biology and Bovine Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
- * E-mail: (JYL); (LYX)
| | - Junya Li
- Laboratory of Molecular Biology and Bovine Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
- * E-mail: (JYL); (LYX)
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17
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Wang Y, Zhu C, Du L, Li Q, Lin MF, Férec C, Cooper DN, Chen JM, Zhou Y. Compound Heterozygosity for Novel Truncating Variants in the LMOD3 Gene as the Cause of Polyhydramnios in Two Successive Fetuses. Front Genet 2019; 10:835. [PMID: 31572445 PMCID: PMC6753228 DOI: 10.3389/fgene.2019.00835] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 08/13/2019] [Indexed: 01/03/2023] Open
Abstract
Polyhydramnios is sometimes associated with genetic defects. However, establishing an accurate diagnosis and pinpointing the precise genetic cause of polyhydramnios in any given case represents a major challenge because it is known to occur in association with over 200 different conditions. Whole exome sequencing (WES) is now a routine part of the clinical workup, particularly with diseases characterized by atypical manifestations and significant genetic heterogeneity. Here we describe the identification, by means of WES, of novel compound heterozygous truncating variants in the LMOD3 gene [i.e., c.1412delA (p.Lys471Serfs*18) and c.1283dupC (p.Gly429Trpfs*35)] in a Chinese family with two successive fetuses affected with polyhydramnios, thereby potentiating the prenatal diagnosis of nemaline myopathy (NM) in the proband. LMOD3 encodes leiomodin-3, which is localized to the pointed ends of thin filaments and acts as a catalyst of actin nucleation in skeletal and cardiac muscle. This is the first study to describe the prenatal and postnatal manifestations of LMOD3-related NM in the Chinese population. Of all the currently reported NM-causing LMOD3 nonsense and frameshifting variants, c.1412delA generates the shortest truncation at the C-terminal end of the protein, underscoring the critical role of the WH2 domain in LMOD3 structure and function. Survey of the prenatal phenotypes of all known LMOD3-related severe NM cases served to identify fetal edema as a novel presenting feature that may provide an early clue to facilitate prenatal diagnosis of the disease.
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Affiliation(s)
- Ye Wang
- Fetal Medicine Center, Department of Obstetrics and Gynecology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Caixia Zhu
- Fetal Medicine Center, Department of Obstetrics and Gynecology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Liu Du
- Department of Ultrasonic Medicine, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Qiaoer Li
- Jiangmen Central Hospital, Affiliated Jiangmen Hospital of Sun Yat-Sen University, Jiangmen, China
| | - Mei-Fang Lin
- Department of Ultrasonic Medicine, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Claude Férec
- EFS, Univ Brest, Inserm, UMR 1078, GGB, Brest, France.,CHU Brest, Service de Génétique, Brest, France
| | - David N Cooper
- Institute of Medical Genetics, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Jian-Min Chen
- EFS, Univ Brest, Inserm, UMR 1078, GGB, Brest, France
| | - Yi Zhou
- Fetal Medicine Center, Department of Obstetrics and Gynecology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
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18
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Abstract
Nemaline myopathy (NM) is among the most common non-dystrophic congenital myopathies (incidence 1:50.000). Hallmark features of NM are skeletal muscle weakness and the presence of nemaline bodies in the muscle fiber. The clinical phenotype of NM patients is quite diverse, ranging from neonatal death to normal lifespan with almost normal motor function. As the respiratory muscles are involved as well, severely affected patients are ventilator-dependent. The mechanisms underlying muscle weakness in NM are currently poorly understood. Therefore, no therapeutic treatment is available yet. Eleven implicated genes have been identified: ten genes encode proteins that are either components of thin filament, or are thought to contribute to stability or turnover of thin filament proteins. The thin filament is a major constituent of the sarcomere, the smallest contractile unit in muscle. It is at this level of contraction – thin-thick filament interaction – where muscle weakness originates in NM patients. This review focusses on how sarcomeric gene mutations directly compromise sarcomere function in NM. Insight into the contribution of sarcomeric dysfunction to muscle weakness in NM, across the genes involved, will direct towards the development of targeted therapeutic strategies.
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Affiliation(s)
| | - Coen A.C. Ottenheijm
- Correspondence to: Coen Ottenheijm, PhD, Department of Physiology, VU University Medical Center, O|2 building, 12W-51, De Boelelaan 1118, 1081 HV Amsterdam, The Netherlands. Tel.: +31 20 4448123; Fax: +31 20 4448124; E-mail:
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19
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Sewry CA, Laitila JM, Wallgren-Pettersson C. Nemaline myopathies: a current view. J Muscle Res Cell Motil 2019; 40:111-126. [PMID: 31228046 PMCID: PMC6726674 DOI: 10.1007/s10974-019-09519-9] [Citation(s) in RCA: 108] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 05/29/2019] [Indexed: 12/13/2022]
Abstract
Nemaline myopathies are a heterogenous group of congenital myopathies caused by de novo, dominantly or recessively inherited mutations in at least twelve genes. The genes encoding skeletal α-actin (ACTA1) and nebulin (NEB) are the commonest genetic cause. Most patients have congenital onset characterized by muscle weakness and hypotonia, but the spectrum of clinical phenotypes is broad, ranging from severe neonatal presentations to onset of a milder disorder in childhood. Most patients with adult onset have an autoimmune-related myopathy with a progressive course. The wide application of massively parallel sequencing methods is increasing the number of known causative genes and broadening the range of clinical phenotypes. Nemaline myopathies are identified by the presence of structures that are rod-like or ovoid in shape with electron microscopy, and with light microscopy stain red with the modified Gömöri trichrome technique. These rods or nemaline bodies are derived from Z lines (also known as Z discs or Z disks) and have a similar lattice structure and protein content. Their shape in patients with mutations in KLHL40 and LMOD3 is distinctive and can be useful for diagnosis. The number and distribution of nemaline bodies varies between fibres and different muscles but does not correlate with severity or prognosis. Additional pathological features such as caps, cores and fibre type disproportion are associated with the same genes as those known to cause the presence of rods. Animal models are advancing the understanding of the effects of various mutations in different genes and paving the way for the development of therapies, which at present only manage symptoms and are aimed at maintaining muscle strength, joint mobility, ambulation, respiration and independence in the activities of daily living.
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Affiliation(s)
- Caroline A Sewry
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health and Great Ormond Street Hospital, 30 Guilford Street, London, WC1N 1EH, UK. .,Wolfson Centre of Inherited Neuromuscular Disorders, RJAH Orthopaedic Hospital, Oswestry, SY10 7AG, UK.
| | - Jenni M Laitila
- Folkhälsan Institute of Genetics, Folkhälsan Research Center, Helsinki, Finland.,Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Carina Wallgren-Pettersson
- Folkhälsan Institute of Genetics, Folkhälsan Research Center, Helsinki, Finland.,Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Helsinki, Finland
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20
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Michael E, Hedberg-Oldfors C, Wilmar P, Visuttijai K, Oldfors A, Darin N. Long-term follow-up and characteristic pathological findings in severe nemaline myopathy due to LMOD3 mutations. Neuromuscul Disord 2018; 29:108-113. [PMID: 30642739 DOI: 10.1016/j.nmd.2018.12.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Revised: 12/01/2018] [Accepted: 12/17/2018] [Indexed: 01/30/2023]
Abstract
We describe the long-term follow-up of a patient with severe nemaline myopathy due to a novel homozygous mutation in the Leiomodin 3 (LMOD3) gene and describe the histopathological characteristics of the disease. The patient presented at birth with hydrops fetalis, multiple joint contractures, severe generalized muscle weakness, no movement, and respiratory insufficiency. At eight years of age, she had bilateral ophthalmoplegia, visual impairment, multiple contractures, and scoliosis, and is dependent on a home mechanical ventilator and gastrostomy. Except for slight head nodding, she has no voluntary movements. Whole-exome sequencing revealed a homozygous one-base duplication in the LMOD3 gene (c.882dupA, p.Asp295Argfs*2), which would result in a truncated protein. Muscle biopsy in the girl and an unrelated patient homozygous for LMOD3 p.Glu357* showed characteristic morphology of the nemaline rods. Many rods appeared as fragments of thickened Z-discs, frequently in pairs, which were interconnected by short thin filaments. Although not specific, this may be a morphological hallmark of LMOD3-associated nemaline myopathy.
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Affiliation(s)
- Eva Michael
- Department of Pediatrics, Sahlgrenska Academy, Institute of Clinical Sciences, Sahlgrenska University Hospital, University of Gothenburg, Gothenburg, Sweden.
| | - Carola Hedberg-Oldfors
- Department of Pathology and Genetics, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Philip Wilmar
- Department of Pediatrics, Sahlgrenska Academy, Institute of Clinical Sciences, Sahlgrenska University Hospital, University of Gothenburg, Gothenburg, Sweden
| | - Kittichate Visuttijai
- Department of Pathology and Genetics, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Anders Oldfors
- Department of Pathology and Genetics, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Niklas Darin
- Department of Pediatrics, Sahlgrenska Academy, Institute of Clinical Sciences, Sahlgrenska University Hospital, University of Gothenburg, Gothenburg, Sweden
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21
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Berkenstadt M, Pode-Shakked B, Barel O, Barash H, Achiron R, Gilboa Y, Kidron D, Raas-Rothschild A. LMOD3-Associated Nemaline Myopathy: Prenatal Ultrasonographic, Pathologic, and Molecular Findings. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2018; 37:1827-1833. [PMID: 29331079 DOI: 10.1002/jum.14520] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 09/29/2017] [Accepted: 10/08/2017] [Indexed: 06/07/2023]
Abstract
To describe the prenatal presentation, including ultrasonographic, histologic, and molecular findings, in 2 fetuses affected with LMOD3-related nemaline myopathy. Prenatal ultrasonographic examinations and histopathologic studies were performed on 2 fetuses with evidence of nemaline myopathy. To establish a molecular diagnosis, whole-exome sequencing was pursued for the affected fetuses. Nemaline myopathy is a common form of congenital myopathy manifesting with nonprogressive generalized muscle weakness, hypotonia, and electron-dense protein inclusions in skeletal myofibers. Although clinically, nemaline myopathy can be viewed as a common pathway phenotype, its molecular basis is heterogeneous, with mutations in 11 identified genes implicated in its pathogenesis so far. Whole-exome sequencing revealed that the affected fetuses were compound heterozygous for 2 newly reported pathogenic variants in the LMOD3 gene, which encodes leiomodin 3. To our knowledge, this article is the first report of LMOD3-related nemaline myopathy since the original reported cohort. We provide a detailed description of the prenatal imaging of these affected fetuses, which we hope, in combination with next-generation sequencing, may contribute to further diagnosis in additional families.
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Affiliation(s)
- Michal Berkenstadt
- Danek Gertner Institute of Human Genetics, Sheba Medical Center, Tel-Hashomer, Israel
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Ben Pode-Shakked
- Danek Gertner Institute of Human Genetics, Sheba Medical Center, Tel-Hashomer, Israel
- Institute for Rare Diseases, Sheba Medical Center, Tel-Hashomer, Israel
- Dr Pinchas Borenstein Talpiot Medical Leadership Program, Sheba Medical Center, Tel-Hashomer, Israel
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Ortal Barel
- Sheba Cancer Research Center, Sheba Medical Center, Tel-Hashomer, Israel
| | - Hila Barash
- Danek Gertner Institute of Human Genetics, Sheba Medical Center, Tel-Hashomer, Israel
- Institute for Rare Diseases, Sheba Medical Center, Tel-Hashomer, Israel
| | - Reuven Achiron
- Department of Obstetrics and Gynecology, Sheba Medical Center, Tel-Hashomer, Israel
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Yinon Gilboa
- Department of Obstetrics and Gynecology, Sheba Medical Center, Tel-Hashomer, Israel
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Dvora Kidron
- Department of Pathology, Meir Medical Center, Kfar Saba, Israel
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Annick Raas-Rothschild
- Danek Gertner Institute of Human Genetics, Sheba Medical Center, Tel-Hashomer, Israel
- Institute for Rare Diseases, Sheba Medical Center, Tel-Hashomer, Israel
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
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22
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Beecroft SJ, Lombard M, Mowat D, McLean C, Cairns A, Davis M, Laing NG, Ravenscroft G. Genetics of neuromuscular fetal akinesia in the genomics era. J Med Genet 2018; 55:505-514. [PMID: 29959180 DOI: 10.1136/jmedgenet-2018-105266] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 03/22/2018] [Accepted: 04/19/2018] [Indexed: 12/27/2022]
Abstract
Fetal hypokinesia or akinesia encompasses a broad spectrum of disorders, united by impaired movement in utero. Often, the underlying aetiology is genetic in origin, affecting part of the neuromuscular system. The affordable and high-throughput nature of next-generation DNA sequencing has led to an explosion in disease gene discovery across rare diseases, including fetal akinesias. A genetic diagnosis has clinical utility as it may affect management and prognosis and informs recurrence risk, facilitating family planning decisions. More broadly, knowledge of disease genes increasingly allows population-based preconception carrier screening, which has reduced the incidence of recessive diseases in several populations. Despite gains in knowledge of the genetics of fetal akinesia, many families lack a genetic diagnosis. In this review, we describe the developments in Mendelian genetics of neuromuscular fetal akinesia in the genomics era. We examine genetic diagnoses with neuromuscular causes, specifically including the lower motor neuron, peripheral nerve, neuromuscular junction and muscle.
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Affiliation(s)
- Sarah Jane Beecroft
- Centre for Medical Research, Faculty of Health and Medical Sciences, The University of Western Australia, Perth, Western Australia, Australia.,Harry Perkins Institute of Medical Research, QQ Block, QEII Medical Centre, Nedlands, Western Australia, Australia
| | - Marcus Lombard
- Centre for Medical Research, Faculty of Health and Medical Sciences, The University of Western Australia, Perth, Western Australia, Australia.,Harry Perkins Institute of Medical Research, QQ Block, QEII Medical Centre, Nedlands, Western Australia, Australia
| | - David Mowat
- Centre for Clinical Genetics, Sydney Children's Hospital, Sydney, New South Wales, Australia
| | - Catriona McLean
- Victorian Neuromuscular Laboratory, Alfred Health, Melbourne, Victoria, Australia
| | - Anita Cairns
- Department of Neurology, Lady Cilento Children's Hospital, Brisbane, Queensland, Australia
| | - Mark Davis
- Neurogenetics Laboratory, Department of Diagnostic Genomics, PP Block, QEII Medical Centre, Nedlands, Western Australia, Australia
| | - Nigel G Laing
- Centre for Medical Research, Faculty of Health and Medical Sciences, The University of Western Australia, Perth, Western Australia, Australia.,Harry Perkins Institute of Medical Research, QQ Block, QEII Medical Centre, Nedlands, Western Australia, Australia
| | - Gianina Ravenscroft
- Centre for Medical Research, Faculty of Health and Medical Sciences, The University of Western Australia, Perth, Western Australia, Australia.,Harry Perkins Institute of Medical Research, QQ Block, QEII Medical Centre, Nedlands, Western Australia, Australia
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23
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Arslan B, Colpan M, Gray KT, Abu-Lail NI, Kostyukova AS. Characterizing interaction forces between actin and proteins of the tropomodulin family reveals the presence of the N-terminal actin-binding site in leiomodin. Arch Biochem Biophys 2017; 638:18-26. [PMID: 29223925 DOI: 10.1016/j.abb.2017.12.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 11/18/2017] [Accepted: 12/05/2017] [Indexed: 11/18/2022]
Abstract
Tropomodulin family of proteins includes several isoforms of tropomodulins (Tmod) and leiomodins (Lmod). These proteins can sequester actin monomers or nucleate actin polymerization. Although it is known that their actin-binding properties are isoform-dependent, knowledge on how they vary in strengths of interactions with G-actin is missing. While it is confirmed in many studies that Tmods have two actin-binding sites, information on number and location of actin-binding sites in Lmod2 is controversial. We used atomic force microscopy to study interactions between G-actin and proteins of the tropomodulin family. Unbinding forces between G-actin and Tmod1, Tmod2, Tmod3, or Lmod2 were quantified. Our results indicated that Tmod1 and Tmod3 had unimodal force distributions, Tmod2 had a bimodal distribution and Lmod2 had a trimodal distribution. The number of force distributions correlates with the proteins' abilities to sequester actin or to nucleate actin polymerization. We assigned specific unbinding forces to the individual actin-binding sites of Tmod2 and Lmod2 using mutations that destroy actin-binding sites of Tmod2 and truncated Lmod2. Our results confirm the existence of the N-terminal actin-binding site in Lmod2. Altogether, our data demonstrate how the differences between the number and the strength of actin-binding sites of Tmod or Lmod translate to their functional abilities.
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Affiliation(s)
- Baran Arslan
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164-6515, United States
| | - Mert Colpan
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164-6515, United States; Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson, AZ 85721, United States
| | - Kevin T Gray
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164-6515, United States
| | - Nehal I Abu-Lail
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164-6515, United States.
| | - Alla S Kostyukova
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164-6515, United States.
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24
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HSPB7 is indispensable for heart development by modulating actin filament assembly. Proc Natl Acad Sci U S A 2017; 114:11956-11961. [PMID: 29078393 DOI: 10.1073/pnas.1713763114] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Small heat shock protein HSPB7 is highly expressed in the heart. Several mutations within HSPB7 are associated with dilated cardiomyopathy and heart failure in human patients. However, the precise role of HSPB7 in the heart is still unclear. In this study, we generated global as well as cardiac-specific HSPB7 KO mouse models and found that loss of HSPB7 globally or specifically in cardiomyocytes resulted in embryonic lethality before embryonic day 12.5. Using biochemical and cell culture assays, we identified HSPB7 as an actin filament length regulator that repressed actin polymerization by binding to monomeric actin. Consistent with HSPB7's inhibitory effects on actin polymerization, HSPB7 KO mice had longer actin/thin filaments and developed abnormal actin filament bundles within sarcomeres that interconnected Z lines and were cross-linked by α-actinin. In addition, loss of HSPB7 resulted in up-regulation of Lmod2 expression and mislocalization of Tmod1. Furthermore, crossing HSPB7 null mice into an Lmod2 null background rescued the elongated thin filament phenotype of HSPB7 KOs, but double KO mice still exhibited formation of abnormal actin bundles and early embryonic lethality. These in vivo findings indicated that abnormal actin bundles, not elongated thin filament length, were the cause of embryonic lethality in HSPB7 KOs. Our findings showed an unsuspected and critical role for a specific small heat shock protein in directly modulating actin thin filament length in cardiac muscle by binding monomeric actin and limiting its availability for polymerization.
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25
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Szatmári D, Bugyi B, Ujfalusi Z, Grama L, Dudás R, Nyitrai M. Cardiac leiomodin2 binds to the sides of actin filaments and regulates the ATPase activity of myosin. PLoS One 2017; 12:e0186288. [PMID: 29023566 PMCID: PMC5638494 DOI: 10.1371/journal.pone.0186288] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2017] [Accepted: 09/28/2017] [Indexed: 12/26/2022] Open
Abstract
Leiomodin proteins are vertebrate homologues of tropomodulin, having a role in the assembly and maintenance of muscle thin filaments. Leiomodin2 contains an N-terminal tropomodulin homolog fragment including tropomyosin-, and actin-binding sites, and a C-terminal Wiskott-Aldrich syndrome homology 2 actin-binding domain. The cardiac leiomodin2 isoform associates to the pointed end of actin filaments, where it supports the lengthening of thin filaments and competes with tropomodulin. It was recently found that cardiac leiomodin2 can localise also along the length of sarcomeric actin filaments. While the activities of leiomodin2 related to pointed end binding are relatively well described, the potential side binding activity and its functional consequences are less well understood. To better understand the biological functions of leiomodin2, in the present work we analysed the structural features and the activities of Rattus norvegicus cardiac leiomodin2 in actin dynamics by spectroscopic and high-speed sedimentation approaches. By monitoring the fluorescence parameters of leiomodin2 tryptophan residues we found that it possesses flexible, intrinsically disordered regions. Leiomodin2 accelerates the polymerisation of actin in an ionic strength dependent manner, which relies on its N-terminal regions. Importantly, we demonstrate that leiomodin2 binds to the sides of actin filaments and induces structural alterations in actin filaments. Upon its interaction with the filaments leiomodin2 decreases the actin-activated Mg2+-ATPase activity of skeletal muscle myosin. These observations suggest that through its binding to side of actin filaments and its effect on myosin activity leiomodin2 has more functions in muscle cells than it was indicated in previous studies.
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Affiliation(s)
- Dávid Szatmári
- University of Pécs, Medical School, Department of Biophysics, Pécs, Hungary
| | - Beáta Bugyi
- University of Pécs, Medical School, Department of Biophysics, Pécs, Hungary
- University of Pécs, Szentágothai Research Centre, Pécs, Hungary
| | - Zoltán Ujfalusi
- University of Pécs, Medical School, Department of Biophysics, Pécs, Hungary
| | - László Grama
- University of Pécs, Medical School, Department of Biophysics, Pécs, Hungary
| | - Réka Dudás
- University of Pécs, Medical School, Department of Biophysics, Pécs, Hungary
| | - Miklós Nyitrai
- University of Pécs, Medical School, Department of Biophysics, Pécs, Hungary
- University of Pécs, Szentágothai Research Centre, Pécs, Hungary
- Hungarian Academy of Sciences-University of Pécs, Nuclear-Mitochondrial Interactions Research Group, Pécs, Hungary
- * E-mail:
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26
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Abbott M, Jain M, Pferdehirt R, Chen Y, Tran A, Duz MB, Seven M, Gibbs RA, Muzny D, Lee B, Marom R, Burrage LC. Neonatal fractures as a presenting feature of LMOD3-associated congenital myopathy. Am J Med Genet A 2017; 173:2789-2794. [PMID: 28815944 DOI: 10.1002/ajmg.a.38383] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 06/14/2017] [Accepted: 07/08/2017] [Indexed: 01/06/2023]
Abstract
Nemaline myopathy is a rare inherited disorder characterized by weakness, hypotonia, and depressed deep tendon reflexes. It is clinically and genetically heterogeneous, with the most severe phenotype presenting as perinatal akinesia, severe muscle weakness, feeding difficulties and respiratory failure, leading to early mortality. Pathogenic variants in 12 genes, encoding components of the sarcomere or factors related to myogenesis, have been reported in patients affected with the disorder. Here, we describe an early, lethal presentation of decreased fetal movements, hypotonia, muscle weakness, and neonatal respiratory failure requiring ventilator support in three siblings from a consanguineous family. All exhibited perinatal fractures, and thus, a skeletal dysplasia was considered as possibly contributing to the phenotype. However, whole exome sequencing revealed a homozygous, loss-of-function pathogenic variant in LMOD3, which has recently been associated with nemaline myopathy and, in a subset of patients, perinatal fractures. This case demonstrates the importance of considering congenital neuromuscular disorders in the differential diagnosis of perinatal fractures.
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Affiliation(s)
- Megan Abbott
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Mahim Jain
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Rachel Pferdehirt
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Yuqing Chen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Alyssa Tran
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Mehmet B Duz
- Department of Medical Genetics, Cerrahpasa Medical School, Istanbul University, Istanbul, Turkey
| | - Mehmet Seven
- Department of Medical Genetics, Cerrahpasa Medical School, Istanbul University, Istanbul, Turkey
| | - Richard A Gibbs
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas
| | - Donna Muzny
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas
| | - Brendan Lee
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Ronit Marom
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Lindsay C Burrage
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
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27
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Ramirez-Martinez A, Cenik BK, Bezprozvannaya S, Chen B, Bassel-Duby R, Liu N, Olson EN. KLHL41 stabilizes skeletal muscle sarcomeres by nonproteolytic ubiquitination. eLife 2017; 6:26439. [PMID: 28826497 PMCID: PMC5589419 DOI: 10.7554/elife.26439] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 08/04/2017] [Indexed: 12/15/2022] Open
Abstract
Maintenance of muscle function requires assembly of contractile proteins into highly organized sarcomeres. Mutations in Kelch-like protein 41 (KLHL41) cause nemaline myopathy, a fatal muscle disorder associated with sarcomere disarray. We generated KLHL41 mutant mice, which display lethal disruption of sarcomeres and aberrant expression of muscle structural and contractile proteins, mimicking the hallmarks of the human disease. We show that KLHL41 is poly-ubiquitinated and acts, at least in part, by preventing aggregation and degradation of Nebulin, an essential component of the sarcomere. Furthermore, inhibition of KLHL41 poly-ubiquitination prevents its stabilization of nebulin, suggesting a unique role for ubiquitination in protein stabilization. These findings provide new insights into the molecular etiology of nemaline myopathy and reveal a mechanism whereby KLHL41 stabilizes sarcomeres and maintains muscle function by acting as a molecular chaperone. Similar mechanisms for protein stabilization likely contribute to the actions of other Kelch proteins.
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Affiliation(s)
- Andres Ramirez-Martinez
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, United States.,Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, United States.,Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, Dallas, United States
| | - Bercin Kutluk Cenik
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, United States.,Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, United States.,Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, Dallas, United States
| | - Svetlana Bezprozvannaya
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, United States.,Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, United States.,Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, Dallas, United States
| | - Beibei Chen
- Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas, United States
| | - Rhonda Bassel-Duby
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, United States.,Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, United States.,Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, Dallas, United States
| | - Ning Liu
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, United States.,Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, United States.,Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, Dallas, United States
| | - Eric N Olson
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, United States.,Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, United States.,Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, Dallas, United States
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28
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Fowler VM, Dominguez R. Tropomodulins and Leiomodins: Actin Pointed End Caps and Nucleators in Muscles. Biophys J 2017; 112:1742-1760. [PMID: 28494946 DOI: 10.1016/j.bpj.2017.03.034] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 03/27/2017] [Accepted: 03/30/2017] [Indexed: 12/29/2022] Open
Abstract
Cytoskeletal structures characterized by actin filaments with uniform lengths, including the thin filaments of striated muscles and the spectrin-based membrane skeleton, use barbed and pointed-end capping proteins to control subunit addition/dissociation at filament ends. While several proteins cap the barbed end, tropomodulins (Tmods), a family of four closely related isoforms in vertebrates, are the only proteins known to specifically cap the pointed end. Tmods are ∼350 amino acids in length, and comprise alternating tropomyosin- and actin-binding sites (TMBS1, ABS1, TMBS2, and ABS2). Leiomodins (Lmods) are related in sequence to Tmods, but display important differences, including most notably the lack of TMBS2 and the presence of a C-terminal extension featuring a proline-rich domain and an actin-binding WASP-Homology 2 domain. The Lmod subfamily comprises three somewhat divergent isoforms expressed predominantly in muscle cells. Biochemically, Lmods differ from Tmods, acting as powerful nucleators of actin polymerization, not capping proteins. Structurally, Lmods and Tmods display crucial differences that correlate well with their different biochemical activities. Physiologically, loss of Lmods in striated muscle results in cardiomyopathy or nemaline myopathy, whereas complete loss of Tmods leads to failure of myofibril assembly and developmental defects. Yet, interpretation of some of the in vivo data has led to the idea that Tmods and Lmods are interchangeable or, at best, different variants of two subfamilies of pointed-end capping proteins. Here, we review and contrast the existing literature on Tmods and Lmods, and propose a model of Lmod function that attempts to reconcile the in vitro and in vivo data, whereby Lmods nucleate actin filaments that are subsequently capped by Tmods during sarcomere assembly, turnover, and repair.
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Affiliation(s)
- Velia M Fowler
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California.
| | - Roberto Dominguez
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.
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29
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Colpan M, Ly T, Grover S, Tolkatchev D, Kostyukova AS. The cardiomyopathy-associated K15N mutation in tropomyosin alters actin filament pointed end dynamics. Arch Biochem Biophys 2017; 630:18-26. [PMID: 28732641 DOI: 10.1016/j.abb.2017.07.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 06/28/2017] [Accepted: 07/13/2017] [Indexed: 10/19/2022]
Abstract
Correct assembly of thin filaments composed of actin and actin-binding proteins is of crucial importance for properly functioning muscle cells. Tropomyosin (Tpm) mediates the binding of tropomodulin (Tmod) and leiomodin (Lmod) at the slow-growing, or pointed, ends of the thin filaments. Together these proteins regulate thin filament lengths and actin dynamics in cardiac muscle. The K15N mutation in the TPM1 gene is associated with familial dilated cardiomyopathy (DCM) but the effect of this mutation on Tpm's function is unknown. In this study, we introduced the K15N mutation in striated muscle α-Tpm (Tpm1.1) and investigated its interaction with actin, Tmod and Lmod. The mutation caused a ∼3-fold decrease in the affinity of Tpm1.1 for actin. The binding of Lmod and Tmod to Tpm1.1-covered actin filaments also decreased in the presence of the K15N mutation. Furthermore, the K15N mutation in Tpm1.1 disrupted the inhibition of actin polymerization and affected the competition between Tmod1 and Lmod2 for binding at the pointed ends. Our data demonstrate that the K15N mutation alters pointed end dynamics by affecting molecular interactions between Tpm1.1, Lmod2 and Tmod1.
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Affiliation(s)
- Mert Colpan
- Voiland School of Chemical Engineering & Bioengineering, Washington State University, Pullman, WA 99164-6515, United States; Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, United States.
| | - Thu Ly
- Voiland School of Chemical Engineering & Bioengineering, Washington State University, Pullman, WA 99164-6515, United States
| | - Samantha Grover
- Voiland School of Chemical Engineering & Bioengineering, Washington State University, Pullman, WA 99164-6515, United States
| | - Dmitri Tolkatchev
- Voiland School of Chemical Engineering & Bioengineering, Washington State University, Pullman, WA 99164-6515, United States
| | - Alla S Kostyukova
- Voiland School of Chemical Engineering & Bioengineering, Washington State University, Pullman, WA 99164-6515, United States.
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30
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Loss of LMOD1 impairs smooth muscle cytocontractility and causes megacystis microcolon intestinal hypoperistalsis syndrome in humans and mice. Proc Natl Acad Sci U S A 2017; 114:E2739-E2747. [PMID: 28292896 DOI: 10.1073/pnas.1620507114] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS) is a congenital visceral myopathy characterized by severe dilation of the urinary bladder and defective intestinal motility. The genetic basis of MMIHS has been ascribed to spontaneous and autosomal dominant mutations in actin gamma 2 (ACTG2), a smooth muscle contractile gene. However, evidence suggesting a recessive origin of the disease also exists. Using combined homozygosity mapping and whole exome sequencing, a genetically isolated family was found to carry a premature termination codon in Leiomodin1 (LMOD1), a gene preferentially expressed in vascular and visceral smooth muscle cells. Parents heterozygous for the mutation exhibited no abnormalities, but a child homozygous for the premature termination codon displayed symptoms consistent with MMIHS. We used CRISPR-Cas9 (CRISPR-associated protein) genome editing of Lmod1 to generate a similar premature termination codon. Mice homozygous for the mutation showed loss of LMOD1 protein and pathology consistent with MMIHS, including late gestation expansion of the bladder, hydronephrosis, and rapid demise after parturition. Loss of LMOD1 resulted in a reduction of filamentous actin, elongated cytoskeletal dense bodies, and impaired intestinal smooth muscle contractility. These results define LMOD1 as a disease gene for MMIHS and suggest its role in establishing normal smooth muscle cytoskeletal-contractile coupling.
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31
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Sanger JW, Wang J, Fan Y, White J, Mi-Mi L, Dube DK, Sanger JM, Pruyne D. Assembly and Maintenance of Myofibrils in Striated Muscle. Handb Exp Pharmacol 2017; 235:39-75. [PMID: 27832381 DOI: 10.1007/164_2016_53] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In this chapter, we present the current knowledge on de novo assembly, growth, and dynamics of striated myofibrils, the functional architectural elements developed in skeletal and cardiac muscle. The data were obtained in studies of myofibrils formed in cultures of mouse skeletal and quail myotubes, in the somites of living zebrafish embryos, and in mouse neonatal and quail embryonic cardiac cells. The comparative view obtained revealed that the assembly of striated myofibrils is a three-step process progressing from premyofibrils to nascent myofibrils to mature myofibrils. This process is specified by the addition of new structural proteins, the arrangement of myofibrillar components like actin and myosin filaments with their companions into so-called sarcomeres, and in their precise alignment. Accompanying the formation of mature myofibrils is a decrease in the dynamic behavior of the assembling proteins. Proteins are most dynamic in the premyofibrils during the early phase and least dynamic in mature myofibrils in the final stage of myofibrillogenesis. This is probably due to increased interactions between proteins during the maturation process. The dynamic properties of myofibrillar proteins provide a mechanism for the exchange of older proteins or a change in isoforms to take place without disassembling the structural integrity needed for myofibril function. An important aspect of myofibril assembly is the role of actin-nucleating proteins in the formation, maintenance, and sarcomeric arrangement of the myofibrillar actin filaments. This is a very active field of research. We also report on several actin mutations that result in human muscle diseases.
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Affiliation(s)
- Joseph W Sanger
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, 766 Irving Avenue, Syracuse, NY, 13224, USA.
| | - Jushuo Wang
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, 766 Irving Avenue, Syracuse, NY, 13224, USA
| | - Yingli Fan
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, 766 Irving Avenue, Syracuse, NY, 13224, USA
| | - Jennifer White
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, 766 Irving Avenue, Syracuse, NY, 13224, USA
| | - Lei Mi-Mi
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, 766 Irving Avenue, Syracuse, NY, 13224, USA
| | - Dipak K Dube
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, 766 Irving Avenue, Syracuse, NY, 13224, USA
| | - Jean M Sanger
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, 766 Irving Avenue, Syracuse, NY, 13224, USA
| | - David Pruyne
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, 766 Irving Avenue, Syracuse, NY, 13224, USA.
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32
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Ow JR, Palanichamy Kala M, Rao VK, Choi MH, Bharathy N, Taneja R. G9a inhibits MEF2C activity to control sarcomere assembly. Sci Rep 2016; 6:34163. [PMID: 27667720 PMCID: PMC5036183 DOI: 10.1038/srep34163] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 09/08/2016] [Indexed: 12/25/2022] Open
Abstract
In this study, we demonstrate that the lysine methyltransferase G9a inhibits sarcomere organization through regulation of the MEF2C-HDAC5 regulatory axis. Sarcomeres are essential for muscle contractile function. Presently, skeletal muscle disease and dysfunction at the sarcomere level has been associated with mutations of sarcomere proteins. This study provides evidence that G9a represses expression of several sarcomere genes and its over-expression disrupts sarcomere integrity of skeletal muscle cells. G9a inhibits MEF2C transcriptional activity that is essential for expression of sarcomere genes. Through protein interaction assays, we demonstrate that G9a interacts with MEF2C and its co-repressor HDAC5. In the presence of G9a, calcium signaling-dependent phosphorylation and export of HDAC5 to the cytoplasm is blocked which likely results in enhanced MEF2C-HDAC5 association. Activation of calcium signaling or expression of constitutively active CaMK rescues G9a-mediated repression of HDAC5 shuttling as well as sarcomere gene expression. Our results demonstrate a novel epigenetic control of sarcomere assembly and identifies new therapeutic avenues to treat skeletal and cardiac myopathies arising from compromised muscle function.
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Affiliation(s)
- Jin Rong Ow
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 117597, Singapore.,NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, 117456, Singapore
| | - Monica Palanichamy Kala
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 117597, Singapore
| | - Vinay Kumar Rao
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 117597, Singapore
| | - Min Hee Choi
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 117597, Singapore.,NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, 117456, Singapore
| | - Narendra Bharathy
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 117597, Singapore
| | - Reshma Taneja
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 117597, Singapore.,NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, 117456, Singapore
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33
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Tobin SW, Yang D, Girgis J, Farahzad A, Blais A, McDermott JC. Regulation of Hspb7 by MEF2 and AP-1: implications for Hspb7 in muscle atrophy. J Cell Sci 2016; 129:4076-4090. [PMID: 27632998 DOI: 10.1242/jcs.190009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 09/08/2016] [Indexed: 12/31/2022] Open
Abstract
Mycocyte enhancer factor 2 (MEF2) and activator protein 1 (AP-1) transcription complexes have been individually implicated in myogenesis, but their genetic interaction has not previously been addressed. Using MEF2A, c-Jun and Fra-1 chromatin immunoprecipitation sequencing (ChIP-seq) data and predicted AP-1 consensus motifs, we identified putative common MEF2 and AP-1 target genes, several of which are implicated in regulating the actin cytoskeleton. Because muscle atrophy results in remodelling or degradation of the actin cytoskeleton, we characterized the expression of putative MEF2 and AP-1 target genes (Dstn, Flnc, Hspb7, Lmod3 and Plekhh2) under atrophic conditions using dexamethasone (Dex) treatment in skeletal myoblasts. Heat shock protein b7 (Hspb7) was induced by Dex treatment and further analyses revealed that loss of MEF2A using siRNA prevented Dex-regulated induction of Hspb7. Conversely, ectopic Fra-2 or c-Jun expression reduced Dex-mediated upregulation of Hspb7 whereas AP-1 depletion enhanced Hspb7 expression. In vivo, expression of Hspb7 and other autophagy-related genes was upregulated in response to atrophic conditions in mice. Manipulation of Hspb7 levels in mice also impacted gross muscle mass. Collectively, these data indicate that MEF2 and AP-1 confer antagonistic regulation of Hspb7 gene expression in skeletal muscle, with implications for autophagy and muscle atrophy.
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Affiliation(s)
- Stephanie Wales Tobin
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3.,Muscle Health Research Centre (MHRC), York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3.,Centre for Research in Biomolecular Interactions (CRBI), 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3
| | - Dabo Yang
- Ottawa Institute of Systems Biology, University of Ottawa, Health Sciences Campus, 451 Smyth Road, Ottawa, Ontario, Canada K1H 8M5
| | - John Girgis
- Ottawa Institute of Systems Biology, University of Ottawa, Health Sciences Campus, 451 Smyth Road, Ottawa, Ontario, Canada K1H 8M5
| | - Ali Farahzad
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3.,Muscle Health Research Centre (MHRC), York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3.,Centre for Research in Biomolecular Interactions (CRBI), 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3
| | - Alexandre Blais
- Ottawa Institute of Systems Biology, University of Ottawa, Health Sciences Campus, 451 Smyth Road, Ottawa, Ontario, Canada K1H 8M5
| | - John C McDermott
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3 .,Muscle Health Research Centre (MHRC), York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3.,Centre for Research in Biomolecular Interactions (CRBI), 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3.,Centre for Research in Mass Spectrometry (CRMS), York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3
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Sandaradura S, North KN. LMOD3: the "missing link" in nemaline myopathy? Oncotarget 2016; 6:26548-9. [PMID: 26337340 PMCID: PMC4694930 DOI: 10.18632/oncotarget.5267] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Indexed: 11/25/2022] Open
Affiliation(s)
- Sarah Sandaradura
- Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead and Discipline of Paediatrics and Child Health, University of Sydney, New South Wales, Australia
| | - Kathryn N North
- Murdoch Children's Research Institute, The Royal Children's Hospital and Department of Paediatrics, University of Melbourne, Victoria, Australia
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Cenik BK, Liu N, Chen B, Bezprozvannaya S, Olson EN, Bassel-Duby R. Myocardin-related transcription factors are required for skeletal muscle development. Development 2016; 143:2853-61. [PMID: 27385017 PMCID: PMC5004908 DOI: 10.1242/dev.135855] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 06/17/2016] [Indexed: 12/24/2022]
Abstract
Myocardin-related transcription factors (MRTFs) play a central role in the regulation of actin expression and cytoskeletal dynamics. Stimuli that promote actin polymerization allow for shuttling of MRTFs to the nucleus where they activate serum response factor (SRF), a regulator of actin and other cytoskeletal protein genes. SRF is an essential regulator of skeletal muscle differentiation and numerous components of the muscle sarcomere, but the potential involvement of MRTFs in skeletal muscle development has not been examined. We explored the role of MRTFs in muscle development in vivo by generating mutant mice harboring a skeletal muscle-specific deletion of MRTF-B and a global deletion of MRTF-A. These double knockout (dKO) mice were able to form sarcomeres during embryogenesis. However, the sarcomeres were abnormally small and disorganized, causing skeletal muscle hypoplasia and perinatal lethality. Transcriptome analysis demonstrated dramatic dysregulation of actin genes in MRTF dKO mice, highlighting the importance of MRTFs in actin cycling and myofibrillogenesis. MRTFs were also shown to be necessary for the survival of skeletal myoblasts and for the efficient formation of intact myotubes. Our findings reveal a central role for MRTFs in sarcomere formation during skeletal muscle development and point to the potential involvement of these transcriptional co-activators in skeletal myopathies.
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Affiliation(s)
- Bercin K Cenik
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA The Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA
| | - Ning Liu
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA The Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA
| | - Beibei Chen
- Clinical Sciences, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA
| | - Svetlana Bezprozvannaya
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA The Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA
| | - Eric N Olson
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA The Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA
| | - Rhonda Bassel-Duby
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA The Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA
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Li S, Mo K, Tian H, Chu C, Sun S, Tian L, Ding S, Li TR, Wu X, Liu F, Zhang Z, Xu T, Sun LV. Lmod2 piggyBac mutant mice exhibit dilated cardiomyopathy. Cell Biosci 2016; 6:38. [PMID: 27274810 PMCID: PMC4893230 DOI: 10.1186/s13578-016-0101-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 05/03/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Leiomodin proteins, Lmod1, Lmod2 and Lmod3, are key regulators of the thin filament length in muscles. While Lmod1 is specifically expressed in smooth muscles, both Lmod2 and Lmod3 are expressed in striated muscles including both cardiac and skeletal muscles. We and others have previously shown that Lmod3 mainly function in skeletal muscles and the mutant mice display disorganized sarcomere. Lmod2 protein has been found to act as an actin filament nucleator in both cell-free assays and in cultured rat and chicken cardiomyocytes. RESULTS To better understand the function of Lmod2 in vivo, we have identified and characterized a piggyBac (PB) insertional mouse mutant. Our analysis revealed that the PB transposon inserts in the first exon of the Lmod2 gene and severely disrupts its expression. We found that Lmod2 (PB/PB) mice exhibit typical dilated cardiomyopathy (DCM) with ventricular arrhythmias and postnatal lethality. Electron microscope reveals that the Lmod2 (PB/PB) hearts carry disordered sarcomere, disarrayed thin filaments, and distorted intercalated discs (ICDs). Those ICDs display not only decreased convolutions, but also reduced electron-dense staining, indicating less ICDs component proteins in Lmod2 (PB/PB) hearts. Consistent with the phenotype, the expression of the ICD component genes, β-catenin and Connexin43, are down-regulated. CONCLUSIONS Taken together, our data reveal that Lmod2 is required in heart thin filaments for integrity of sarcomere and ICD and deficient mice exhibit DCM with ventricular arrhythmias and postnatal lethality. The Lmod2 (PB/PB) mutant offers a valuable resource for interrogation of pathogenesis and development of therapeutics for DCM.
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Affiliation(s)
- Shuang Li
- State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Fudan-Yale Center for Biomedical Research, Innovation Center for International Cooperation of Genetics and Development, Institute of Developmental Biology and Molecular Medicine, School of Life Sciences, Children's Hospital of Fudan University, Fudan University, Shanghai, China
| | - Kaiqi Mo
- State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Fudan-Yale Center for Biomedical Research, Innovation Center for International Cooperation of Genetics and Development, Institute of Developmental Biology and Molecular Medicine, School of Life Sciences, Children's Hospital of Fudan University, Fudan University, Shanghai, China
| | - Hong Tian
- Cardiac Center, Children's Hospital of Fudan University, Shanghai, China
| | - Chen Chu
- Cardiac Center, Children's Hospital of Fudan University, Shanghai, China
| | - Shuna Sun
- Cardiac Center, Children's Hospital of Fudan University, Shanghai, China
| | - Lei Tian
- State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Fudan-Yale Center for Biomedical Research, Innovation Center for International Cooperation of Genetics and Development, Institute of Developmental Biology and Molecular Medicine, School of Life Sciences, Children's Hospital of Fudan University, Fudan University, Shanghai, China ; Howard Hughes Medical Institute, Department of Genetics, Yale University School of Medicine, New Haven, CT USA
| | - Sheng Ding
- State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Fudan-Yale Center for Biomedical Research, Innovation Center for International Cooperation of Genetics and Development, Institute of Developmental Biology and Molecular Medicine, School of Life Sciences, Children's Hospital of Fudan University, Fudan University, Shanghai, China ; Howard Hughes Medical Institute, Department of Genetics, Yale University School of Medicine, New Haven, CT USA
| | - Tong-Ruei Li
- State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Fudan-Yale Center for Biomedical Research, Innovation Center for International Cooperation of Genetics and Development, Institute of Developmental Biology and Molecular Medicine, School of Life Sciences, Children's Hospital of Fudan University, Fudan University, Shanghai, China
| | - Xiaohui Wu
- State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Fudan-Yale Center for Biomedical Research, Innovation Center for International Cooperation of Genetics and Development, Institute of Developmental Biology and Molecular Medicine, School of Life Sciences, Children's Hospital of Fudan University, Fudan University, Shanghai, China
| | - Fang Liu
- Cardiac Center, Children's Hospital of Fudan University, Shanghai, China
| | - Zhen Zhang
- Shanghai Pediatric Congenital Heart Institute, Institute of Pediatric Translational Medicine, Shanghai Children's Medical Center, Shanghai Jiaotong University, School of Medicine, Shanghai, China
| | - Tian Xu
- State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Fudan-Yale Center for Biomedical Research, Innovation Center for International Cooperation of Genetics and Development, Institute of Developmental Biology and Molecular Medicine, School of Life Sciences, Children's Hospital of Fudan University, Fudan University, Shanghai, China ; Howard Hughes Medical Institute, Department of Genetics, Yale University School of Medicine, New Haven, CT USA
| | - Ling V Sun
- State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Fudan-Yale Center for Biomedical Research, Innovation Center for International Cooperation of Genetics and Development, Institute of Developmental Biology and Molecular Medicine, School of Life Sciences, Children's Hospital of Fudan University, Fudan University, Shanghai, China
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Serum Response Factor Protects Retinal Ganglion Cells Against High-Glucose Damage. J Mol Neurosci 2016; 59:232-40. [PMID: 26803311 DOI: 10.1007/s12031-015-0708-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 12/23/2015] [Indexed: 12/22/2022]
Abstract
Serum response factor (SRF), which encodes the MADS-box family of related proteins, is a common transcription factor related to the expression of genes associated with cell survival. However, SRF's role in retinal ganglion cells (RGCs) after high-glucose injury remains unclear. In this study, we investigate the protective role of SRF after high-glucose injury and its underlying mechanism. The in vitro RGC model subjected to high glucose was established by employing a 50 mmol/L glucose culture environment. As detected by real-time quantitative PCR and Western blot, SRF was significantly upregulated in RGCs treated with high glucose. Overexpression of SRF significantly promoted survival among RGCs exposed to high glucose and inhibited RGC apoptosis. Knockdown of SRF exerted an inverse effect. Moreover, SRF upregulation enhanced expression of an antioxidant protein, nuclear factor erythroid 2-related factor (Nrf2), via control of the Fos-related antigen 1 (Fra-1). SRF upregulation also affected RGC survival after high-glucose treatment. Our findings showed that overexpression of SRF promoted survival of RGCs after high-glucose injury by regulating Fra-1 and Nrf2.
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Abstract
Efficient muscle contraction in skeletal muscle is predicated on the regulation of actin filament lengths. In one long-standing model that was prominent for decades, the giant protein nebulin was proposed to function as a 'molecular ruler' to specify the lengths of the thin filaments. This theory was questioned by many observations, including experiments in which the length of nebulin was manipulated in skeletal myocytes; this approach revealed that nebulin functions to stabilize filamentous actin, allowing thin filaments to reach mature lengths. In addition, more recent data, mostly from in vivo models and identification of new interacting partners, have provided evidence that nebulin is not merely a structural protein. Nebulin plays a role in numerous cellular processes including regulation of muscle contraction, Z-disc formation, and myofibril organization and assembly.
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Affiliation(s)
- Miensheng Chu
- Department of Cellular and Molecular Medicine and the Sarver Molecular Cardiovascular Research Program, The University of Arizona, 1656 East Mabel, MRB315, Tucson, AZ 85724, USA
| | - Carol C Gregorio
- Department of Cellular and Molecular Medicine and the Sarver Molecular Cardiovascular Research Program, The University of Arizona, 1656 East Mabel, MRB315, Tucson, AZ 85724, USA
| | - Christopher T Pappas
- Department of Cellular and Molecular Medicine and the Sarver Molecular Cardiovascular Research Program, The University of Arizona, 1656 East Mabel, MRB315, Tucson, AZ 85724, USA
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Gokhin DS, Ochala J, Domenighetti AA, Fowler VM. Tropomodulin 1 directly controls thin filament length in both wild-type and tropomodulin 4-deficient skeletal muscle. Development 2015; 142:4351-62. [PMID: 26586224 DOI: 10.1242/dev.129171] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 11/05/2015] [Indexed: 01/10/2023]
Abstract
The sarcomeric tropomodulin (Tmod) isoforms Tmod1 and Tmod4 cap thin filament pointed ends and functionally interact with the leiomodin (Lmod) isoforms Lmod2 and Lmod3 to control myofibril organization, thin filament lengths, and actomyosin crossbridge formation in skeletal muscle fibers. Here, we show that Tmod4 is more abundant than Tmod1 at both the transcript and protein level in a variety of muscle types, but the relative abundances of sarcomeric Tmods are muscle specific. We then generate Tmod4(-/-) mice, which exhibit normal thin filament lengths, myofibril organization, and skeletal muscle contractile function owing to compensatory upregulation of Tmod1, together with an Lmod isoform switch wherein Lmod3 is downregulated and Lmod2 is upregulated. However, RNAi depletion of Tmod1 from either wild-type or Tmod4(-/-) muscle fibers leads to thin filament elongation by ∼15%. Thus, Tmod1 per se, rather than total sarcomeric Tmod levels, controls thin filament lengths in mouse skeletal muscle, whereas Tmod4 appears to be dispensable for thin filament length regulation. These findings identify Tmod1 as the key direct regulator of thin filament length in skeletal muscle, in both adult muscle homeostasis and in developmentally compensated contexts.
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Affiliation(s)
- David S Gokhin
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Julien Ochala
- Centre of Human and Aerospace Physiological Sciences, King's College London, London SE1 1UL, UK
| | - Andrea A Domenighetti
- Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA Rehabilitation Institute of Chicago, Chicago, IL 60611, USA
| | - Velia M Fowler
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
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40
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Todd EJ, Yau KS, Ong R, Slee J, McGillivray G, Barnett CP, Haliloglu G, Talim B, Akcoren Z, Kariminejad A, Cairns A, Clarke NF, Freckmann ML, Romero NB, Williams D, Sewry CA, Colley A, Ryan MM, Kiraly-Borri C, Sivadorai P, Allcock RJN, Beeson D, Maxwell S, Davis MR, Laing NG, Ravenscroft G. Next generation sequencing in a large cohort of patients presenting with neuromuscular disease before or at birth. Orphanet J Rare Dis 2015; 10:148. [PMID: 26578207 PMCID: PMC4650299 DOI: 10.1186/s13023-015-0364-0] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 11/02/2015] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Fetal akinesia/hypokinesia, arthrogryposis and severe congenital myopathies are heterogeneous conditions usually presenting before or at birth. Although numerous causative genes have been identified for each of these disease groups, in many cases a specific genetic diagnosis remains elusive. Due to the emergence of next generation sequencing, virtually the entire coding region of an individual's DNA can now be analysed through "whole" exome sequencing, enabling almost all known and novel disease genes to be investigated for disorders such as these. METHODS Genomic DNA samples from 45 patients with fetal akinesia/hypokinesia, arthrogryposis or severe congenital myopathies from 38 unrelated families were subjected to next generation sequencing. Clinical features and diagnoses for each patient were supplied by referring clinicians. Genomic DNA was used for either whole exome sequencing or a custom-designed neuromuscular sub-exomic supercapture array containing 277 genes responsible for various neuromuscular diseases. Candidate disease-causing variants were investigated and confirmed using Sanger sequencing. Some of the cases within this cohort study have been published previously as separate studies. RESULTS A conclusive genetic diagnosis was achieved for 18 of the 38 families. Within this cohort, mutations were found in eight previously known neuromuscular disease genes (CHRND, CHNRG, ECEL1, GBE1, MTM1, MYH3, NEB and RYR1) and four novel neuromuscular disease genes were identified and have been published as separate reports (GPR126, KLHL40, KLHL41 and SPEG). In addition, novel mutations were identified in CHRND, KLHL40, NEB and RYR1. Autosomal dominant, autosomal recessive, X-linked, and de novo modes of inheritance were observed. CONCLUSIONS By using next generation sequencing on a cohort of 38 unrelated families with fetal akinesia/hypokinesia, arthrogryposis, or severe congenital myopathy we therefore obtained a genetic diagnosis for 47% of families. This study highlights the power and capacity of next generation sequencing (i) to determine the aetiology of genetically heterogeneous neuromuscular diseases, (ii) to identify novel disease genes in small pedigrees or isolated cases and (iii) to refine the interplay between genetic diagnosis and clinical evaluation and management.
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Affiliation(s)
- Emily J Todd
- Harry Perkins Institute of Medical Research and the Centre for Medical Research, University of Western Australia, QQ Block, 6 Verdun Street, Nedlands, 6009, , WA, Australia.
| | - Kyle S Yau
- Harry Perkins Institute of Medical Research and the Centre for Medical Research, University of Western Australia, QQ Block, 6 Verdun Street, Nedlands, 6009, , WA, Australia.
| | - Royston Ong
- Harry Perkins Institute of Medical Research and the Centre for Medical Research, University of Western Australia, QQ Block, 6 Verdun Street, Nedlands, 6009, , WA, Australia.
| | - Jennie Slee
- Genetic Services of Western Australia, King Edward Memorial Hospital, Perth, 6000, , WA, Australia.
| | - George McGillivray
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, The Royal Children's Hospital, Parkville, 3052, , VIC, Australia.
| | - Christopher P Barnett
- Paediatric and Reproductive Genetics Unit, South Australia Clinical Genetics Service, Women's and Children's Hospital, North Adelaide, 5006, , SA, Australia.
| | - Goknur Haliloglu
- Department of Pediatric Neurology, Hacettepe University Children's Hospital, Ankara, 06100, Turkey.
| | - Beril Talim
- Pediatric Pathology Unit, Hacettepe University Children's Hospital, Ankara, 06100, Turkey.
| | - Zuhal Akcoren
- Pediatric Pathology Unit, Hacettepe University Children's Hospital, Ankara, 06100, Turkey.
| | - Ariana Kariminejad
- Kariminejad-Najmabadi Pathology and Genetics Centre, Tehran, 14656, Iran.
| | - Anita Cairns
- Royal Children's Hospital, Herston Road, Herson, 4029, , QLD, Australia.
| | - Nigel F Clarke
- Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, 2145, , NSW, Australia. .,Discipline of Paediatrics and Child Health, University of Sydney, Sydney, 2006, , NSW, Australia.
| | | | - Norma B Romero
- Unitè de Morphologie Neuromusculaire, Institut de Myologie, Institut National de la Santè et de la Recherche Mèdicale, Paris, 75651, France.
| | - Denise Williams
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health, London, WC1N 1EH, UK. .,Wolfson Centre for Neuromuscular Disorders, RJAH Orthopaedic Hospital, Oswestry, SY10 7AG, UK.
| | - Caroline A Sewry
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health, London, WC1N 1EH, UK. .,Wolfson Centre for Neuromuscular Disorders, RJAH Orthopaedic Hospital, Oswestry, SY10 7AG, UK.
| | - Alison Colley
- Department of Clinical Genetics, South Western Sydney Local Health District, Liverpool, 1871, , NSW, Australia.
| | - Monique M Ryan
- Department of Neurology, The Royal Children's Hospital, Melbourne, 3000, , VIC, Australia.
| | - Cathy Kiraly-Borri
- Genetic Services of Western Australia, Princess Margaret Hospital for Children and King Edward Memorial Hospital for Women, Subiaco, 6008, , WA, Australia.
| | - Padma Sivadorai
- Department of Diagnostic Genomics, Pathwest, QEII Medical Centre, Nedlands, 6009, , WA, Australia.
| | - Richard J N Allcock
- Lotterywest State Biomedical Facility Genomics and School of Pathology and Laboratory Medicine, University of Western Australia, Perth, 6000, , WA, Australia.
| | - David Beeson
- Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX3 9DS, UK.
| | - Susan Maxwell
- Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX3 9DS, UK.
| | - Mark R Davis
- Department of Diagnostic Genomics, Pathwest, QEII Medical Centre, Nedlands, 6009, , WA, Australia.
| | - Nigel G Laing
- Harry Perkins Institute of Medical Research and the Centre for Medical Research, University of Western Australia, QQ Block, 6 Verdun Street, Nedlands, 6009, , WA, Australia. .,Department of Diagnostic Genomics, Pathwest, QEII Medical Centre, Nedlands, 6009, , WA, Australia.
| | - Gianina Ravenscroft
- Harry Perkins Institute of Medical Research and the Centre for Medical Research, University of Western Australia, QQ Block, 6 Verdun Street, Nedlands, 6009, , WA, Australia.
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Knockout of Lmod2 results in shorter thin filaments followed by dilated cardiomyopathy and juvenile lethality. Proc Natl Acad Sci U S A 2015; 112:13573-8. [PMID: 26487682 DOI: 10.1073/pnas.1508273112] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Leiomodin 2 (Lmod2) is an actin-binding protein that has been implicated in the regulation of striated muscle thin filament assembly; its physiological function has yet to be studied. We found that knockout of Lmod2 in mice results in abnormally short thin filaments in the heart. We also discovered that Lmod2 functions to elongate thin filaments by promoting actin assembly and dynamics at thin filament pointed ends. Lmod2-KO mice die as juveniles with hearts displaying contractile dysfunction and ventricular chamber enlargement consistent with dilated cardiomyopathy. Lmod2-null cardiomyocytes produce less contractile force than wild type when plated on micropillar arrays. Introduction of GFP-Lmod2 via adeno-associated viral transduction elongates thin filaments and rescues structural and functional defects observed in Lmod2-KO mice, extending their lifespan to adulthood. Thus, to our knowledge, Lmod2 is the first identified mammalian protein that functions to elongate actin filaments in the heart; it is essential for cardiac thin filaments to reach a mature length and is required for efficient contractile force and proper heart function during development.
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42
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How Leiomodin and Tropomodulin use a common fold for different actin assembly functions. Nat Commun 2015; 6:8314. [PMID: 26370058 PMCID: PMC4571291 DOI: 10.1038/ncomms9314] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 08/07/2015] [Indexed: 11/08/2022] Open
Abstract
How proteins sharing a common fold have evolved different functions is a fundamental question in biology. Tropomodulins (Tmods) are prototypical actin filament pointed-end-capping proteins, whereas their homologues, Leiomodins (Lmods), are powerful filament nucleators. We show that Tmods and Lmods do not compete biochemically, and display similar but distinct localization in sarcomeres. Changes along the polypeptide chains of Tmods and Lmods exquisitely adapt their functions for capping versus nucleation. Tmods have alternating tropomyosin (TM)- and actin-binding sites (TMBS1, ABS1, TMBS2 and ABS2). Lmods additionally contain a C-terminal extension featuring an actin-binding WH2 domain. Unexpectedly, the different activities of Tmods and Lmods do not arise from the Lmod-specific extension. Instead, nucleation by Lmods depends on two major adaptations-the loss of pointed-end-capping elements present in Tmods and the specialization of the highly conserved ABS2 for recruitment of two or more actin subunits. The WH2 domain plays only an auxiliary role in nucleation.
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43
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Tian L, Ding S, You Y, Li TR, Liu Y, Wu X, Sun L, Xu T. Leiomodin-3-deficient mice display nemaline myopathy with fast-myofiber atrophy. Dis Model Mech 2015; 8:635-41. [PMID: 26035871 PMCID: PMC4457035 DOI: 10.1242/dmm.019430] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 04/10/2015] [Indexed: 12/24/2022] Open
Abstract
Nemaline myopathy (NM) is one of the most common forms of congenital myopathy, and affects either fast myofibers, slow myofibers, or both. However, an animal model for congenital myopathy with fast-myofiber-specific atrophy is not available. Furthermore, mutations in the leiomodin-3 (LMOD3) gene have recently been identified in a group of individuals with NM. However, it is not clear how loss of LMOD3 leads to NM. Here, we report a mouse mutant in which the piggyBac (PB) transposon is inserted into the Lmod3 gene and disrupts its expression. Lmod3PB/PB mice show severe muscle weakness and postnatal growth retardation. Electron microscopy and immunofluorescence studies of the mutant skeletal muscles revealed the presence of nemaline bodies, a hallmark of NM, and disorganized sarcomeric structures. Interestingly, Lmod3 deficiency caused muscle atrophy specific to the fast fibers. Together, our results show that Lmod3 is required in the fast fibers for sarcomere integrity, and this study offers the first NM mouse model with muscle atrophy that is specific to fast fibers. This model could be a valuable resource for interrogating myopathy pathogenesis and developing therapeutics for NM as well as other pathophysiological conditions with preferential atrophy of fast fibers, including cancer cachexia and sarcopenia. Highlighted Article: A leiomodin-3 mouse mutant generated by insertion of the piggyBac transposon exhibits nemaline myopathy with fast-myofiber-specific atrophy.
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Affiliation(s)
- Lei Tian
- State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Fudan-Yale Center for Biomedical Research, Innovation Center for International Cooperation of Genetics and Development, Institute of Developmental Biology and Molecular Medicine, School of Life Sciences, Fudan University, Shanghai 200433, China Howard Hughes Medical Institute, Department of Genetics, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Sheng Ding
- State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Fudan-Yale Center for Biomedical Research, Innovation Center for International Cooperation of Genetics and Development, Institute of Developmental Biology and Molecular Medicine, School of Life Sciences, Fudan University, Shanghai 200433, China Howard Hughes Medical Institute, Department of Genetics, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Yun You
- Howard Hughes Medical Institute, Department of Genetics, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Tong-ruei Li
- State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Fudan-Yale Center for Biomedical Research, Innovation Center for International Cooperation of Genetics and Development, Institute of Developmental Biology and Molecular Medicine, School of Life Sciences, Fudan University, Shanghai 200433, China Howard Hughes Medical Institute, Department of Genetics, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Yan Liu
- State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Fudan-Yale Center for Biomedical Research, Innovation Center for International Cooperation of Genetics and Development, Institute of Developmental Biology and Molecular Medicine, School of Life Sciences, Fudan University, Shanghai 200433, China Howard Hughes Medical Institute, Department of Genetics, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Xiaohui Wu
- State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Fudan-Yale Center for Biomedical Research, Innovation Center for International Cooperation of Genetics and Development, Institute of Developmental Biology and Molecular Medicine, School of Life Sciences, Fudan University, Shanghai 200433, China
| | - Ling Sun
- State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Fudan-Yale Center for Biomedical Research, Innovation Center for International Cooperation of Genetics and Development, Institute of Developmental Biology and Molecular Medicine, School of Life Sciences, Fudan University, Shanghai 200433, China
| | - Tian Xu
- State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Fudan-Yale Center for Biomedical Research, Innovation Center for International Cooperation of Genetics and Development, Institute of Developmental Biology and Molecular Medicine, School of Life Sciences, Fudan University, Shanghai 200433, China Howard Hughes Medical Institute, Department of Genetics, Yale University School of Medicine, New Haven, CT 06536, USA
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