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Ahmad N, de la Serna IL, Marathe HG, Fan X, Dube P, Zhang S, Haller ST, Kennedy DJ, Pestov NB, Modyanov NN. Eutherian-Specific Functions of BetaM Acquired through Atp1b4 Gene Co-Option in the Regulation of MyoD Expression. Life (Basel) 2023; 13:414. [PMID: 36836771 PMCID: PMC9962273 DOI: 10.3390/life13020414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 01/20/2023] [Accepted: 01/31/2023] [Indexed: 02/05/2023] Open
Abstract
Vertebrate ATP1B4 genes represent a rare instance of orthologous gene co-option, resulting in radically different functions of the encoded BetaM proteins. In lower vertebrates, BetaM is a Na, K-ATPase β-subunit that is a component of ion pumps in the plasma membrane. In placental mammals, BetaM lost its ancestral role and, through structural alterations of the N-terminal domain, became a skeletal and cardiac muscle-specific protein of the inner nuclear membrane, highly expressed during late fetal and early postnatal development. We previously determined that BetaM directly interacts with the transcriptional co-regulator SKI-interacting protein (SKIP) and is implicated in the regulation of gene expression. This prompted us to investigate a potential role for BetaM in the regulation of muscle-specific gene expression in neonatal skeletal muscle and cultured C2C12 myoblasts. We found that BetaM can stimulate expression of the muscle regulatory factor (MRF), MyoD, independently of SKIP. BetaM binds to the distal regulatory region (DRR) of MyoD, promotes epigenetic changes associated with activation of transcription, and recruits the SWI/SNF chromatin remodeling subunit, BRG1. These results indicate that eutherian BetaM regulates muscle gene expression by promoting changes in chromatin structure. These evolutionarily acquired new functions of BetaM might be very essential and provide evolutionary advantages to placental mammals.
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Affiliation(s)
- Nisar Ahmad
- Department of Physiology and Pharmacology, Center for Diabetes and Endocrine Research, College of Medicine and Life Sciences, The University of Toledo, Toledo, OH 43614, USA
| | - Ivana L. de la Serna
- Department of Cell and Cancer Biology, College of Medicine and Life Sciences, The University of Toledo, Toledo, OH 43614, USA
| | - Himangi G. Marathe
- Department of Cell and Cancer Biology, College of Medicine and Life Sciences, The University of Toledo, Toledo, OH 43614, USA
| | - Xiaoming Fan
- Department of Medicine, College of Medicine and Life Sciences, The University of Toledo, Toledo, OH 43614, USA
| | - Prabhatchandra Dube
- Department of Medicine, College of Medicine and Life Sciences, The University of Toledo, Toledo, OH 43614, USA
| | - Shungang Zhang
- Department of Medicine, College of Medicine and Life Sciences, The University of Toledo, Toledo, OH 43614, USA
| | - Steven T. Haller
- Department of Medicine, College of Medicine and Life Sciences, The University of Toledo, Toledo, OH 43614, USA
| | - David J. Kennedy
- Department of Medicine, College of Medicine and Life Sciences, The University of Toledo, Toledo, OH 43614, USA
| | - Nikolay B. Pestov
- Department of Physiology and Pharmacology, Center for Diabetes and Endocrine Research, College of Medicine and Life Sciences, The University of Toledo, Toledo, OH 43614, USA
| | - Nikolai N. Modyanov
- Department of Physiology and Pharmacology, Center for Diabetes and Endocrine Research, College of Medicine and Life Sciences, The University of Toledo, Toledo, OH 43614, USA
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Autosomal dominant Emery-Dreifuss muscular dystrophy caused by a mutation in the lamin A/C gene identified by exome sequencing: a case report. BMC Pediatr 2022; 22:601. [PMID: 36253810 PMCID: PMC9575219 DOI: 10.1186/s12887-022-03662-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 10/10/2022] [Indexed: 11/16/2022] Open
Abstract
Background Emery-Dreifuss Muscular Dystrophy (EDMD) is an uncommon genetic disease among the group of muscular dystrophies. EDMD is clinically heterogeneous and resembles other muscular dystrophies. Mutation of the lamin A/C (LMNA) gene, which causes EDMD, also causes many other diseases. There is inter and intrafamilial variability in clinical presentations. Precise diagnosis can help in patient surveillance, especially before they present with cardiac problems. Hence, this paper shows how a molecular work-out by next-generation sequencing can help this group of disorders. Case presentation A 2-year-10-month-old Javanese boy presented to our clinic with weakness in lower limbs and difficulty climbing stairs. The clinical features of the boy were Gower's sign, waddling gait and high CK level. His father presented with elbow contractures and heels, toe walking and weakness of limbs, pelvic, and peroneus muscles. Exome sequencing on this patient detected a pathogenic variant in the LMNA gene (NM_170707: c.C1357T: NP_733821: p.Arg453Trp) that has been reported to cause Autosomal Dominant Emery-Dreifuss muscular dystrophy. Further examination showed total atrioventricular block and atrial fibrillation in the father. Conclusion EDMD is a rare disabling muscular disease that poses a diagnostic challenge. Family history work-up and thorough neuromuscular physical examinations are needed. Early diagnosis is essential to recognize orthopaedic and cardiac complications, improving the clinical management and prognosis of the disease. Exome sequencing could successfully determine pathogenic variants to provide a conclusive diagnosis.
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Srivastava LK, Ju Z, Ghagre A, Ehrlicher AJ. Spatial distribution of lamin A/C determines nuclear stiffness and stress-mediated deformation. J Cell Sci 2021; 134:268336. [PMID: 34028539 PMCID: PMC8186481 DOI: 10.1242/jcs.248559] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 04/14/2021] [Indexed: 01/05/2023] Open
Abstract
While diverse cellular components have been identified as mechanotransduction elements, the deformation of the nucleus itself is a critical mechanosensory mechanism, implying that nuclear stiffness is essential in determining responses to intracellular and extracellular stresses. Although the nuclear membrane protein lamin A/C is known to contribute to nuclear stiffness, bulk moduli of nuclei have not been reported for various levels of lamin A/C. Here, we measure the nuclear bulk moduli as a function of lamin A/C expression and applied osmotic stress, revealing a linear dependence within the range of 2-4 MPa. We also find that the nuclear compression is anisotropic, with the vertical axis of the nucleus being more compliant than the minor and major axes in the substrate plane. We then related the spatial distribution of lamin A/C with submicron 3D nuclear envelope deformation, revealing that local areas of the nuclear envelope with higher density of lamin A/C have correspondingly lower local deformations. These findings describe the complex dispersion of nuclear deformations as a function of lamin A/C expression and distribution, implicating a lamin A/C role in mechanotransduction. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
| | - Zhaoping Ju
- Department of Anatomy and Cell Biology, McGill University, Montreal H3A 0C7, Canada
| | - Ajinkya Ghagre
- Department of Bioengineering, McGill University, Montreal H3A 0E9
| | - Allen J Ehrlicher
- Department of Bioengineering, McGill University, Montreal H3A 0E9.,Department of Anatomy and Cell Biology, McGill University, Montreal H3A 0C7, Canada.,Department of Biomedical Engineering, McGill University, Montreal H3A 2B4, Canada.,Department of Mechanical Engineering, McGill University, Montreal H3A 0C3.,Centre for Structural Biology, McGill University, Montreal H3G 0B1, Canada.,Goodman Cancer Research Centre, McGill University, Montreal H3A 1A3, Canada
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PCAF Involvement in Lamin A/C-HDAC2 Interplay during the Early Phase of Muscle Differentiation. Cells 2020; 9:cells9071735. [PMID: 32698523 PMCID: PMC7409167 DOI: 10.3390/cells9071735] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 07/09/2020] [Accepted: 07/17/2020] [Indexed: 02/07/2023] Open
Abstract
Lamin A/C has been implicated in the epigenetic regulation of muscle gene expression through dynamic interaction with chromatin domains and epigenetic enzymes. We previously showed that lamin A/C interacts with histone deacetylase 2 (HDAC2). In this study, we deepened the relevance and regulation of lamin A/C-HDAC2 interaction in human muscle cells. We present evidence that HDAC2 binding to lamina A/C is related to HDAC2 acetylation on lysine 75 and expression of p300-CBP associated factor (PCAF), an acetyltransferase known to acetylate HDAC2. Our findings show that lamin A and farnesylated prelamin A promote PCAF recruitment to the nuclear lamina and lamin A/C binding in human myoblasts committed to myogenic differentiation, while protein interaction is decreased in differentiating myotubes. Interestingly, PCAF translocation to the nuclear envelope, as well as lamin A/C-PCAF interaction, are reduced by transient expression of lamin A mutated forms causing Emery Dreifuss muscular dystrophy. Consistent with this observation, lamin A/C interaction with both PCAF and HDAC2 is significantly reduced in Emery-Dreifuss muscular dystrophy myoblasts. Overall, these results support the view that, by recruiting PCAF and HDAC2 in a molecular platform, lamin A/C might contribute to regulate their epigenetic activity required in the early phase of muscle differentiation.
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Muscle cell differentiation and development pathway defects in Emery-Dreifuss muscular dystrophy. Neuromuscul Disord 2020; 30:443-456. [DOI: 10.1016/j.nmd.2020.04.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 03/20/2020] [Accepted: 04/15/2020] [Indexed: 12/12/2022]
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Epigenetic Factors That Control Pericentric Heterochromatin Organization in Mammals. Genes (Basel) 2020; 11:genes11060595. [PMID: 32481609 PMCID: PMC7349813 DOI: 10.3390/genes11060595] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 05/17/2020] [Accepted: 05/25/2020] [Indexed: 12/11/2022] Open
Abstract
Pericentric heterochromatin (PCH) is a particular form of constitutive heterochromatin that is localized to both sides of centromeres and that forms silent compartments enriched in repressive marks. These genomic regions contain species-specific repetitive satellite DNA that differs in terms of nucleotide sequences and repeat lengths. In spite of this sequence diversity, PCH is involved in many biological phenomena that are conserved among species, including centromere function, the preservation of genome integrity, the suppression of spurious recombination during meiosis, and the organization of genomic silent compartments in the nucleus. PCH organization and maintenance of its repressive state is tightly regulated by a plethora of factors, including enzymes (e.g., DNA methyltransferases, histone deacetylases, and histone methyltransferases), DNA and histone methylation binding factors (e.g., MECP2 and HP1), chromatin remodeling proteins (e.g., ATRX and DAXX), and non-coding RNAs. This evidence helps us to understand how PCH organization is crucial for genome integrity. It then follows that alterations to the molecular signature of PCH might contribute to the onset of many genetic pathologies and to cancer progression. Here, we describe the most recent updates on the molecular mechanisms known to underlie PCH organization and function.
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Gil L, Niño SA, Chi-Ahumada E, Rodríguez-Leyva I, Guerrero C, Rebolledo AB, Arias JA, Jiménez-Capdeville ME. Perinuclear Lamin A and Nucleoplasmic Lamin B2 Characterize Two Types of Hippocampal Neurons through Alzheimer's Disease Progression. Int J Mol Sci 2020; 21:E1841. [PMID: 32155994 PMCID: PMC7084765 DOI: 10.3390/ijms21051841] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 02/28/2020] [Accepted: 03/03/2020] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Recent reports point to a nuclear origin of Alzheimer's disease (AD). Aged postmitotic neurons try to repair their damaged DNA by entering the cell cycle. This aberrant cell cycle re-entry involves chromatin modifications where nuclear Tau and the nuclear lamin are involved. The purpose of this work was to elucidate their participation in the nuclear pathological transformation of neurons at early AD. METHODOLOGY The study was performed in hippocampal paraffin embedded sections of adult, senile, and AD brains at I-VI Braak stages. We analyzed phospho-Tau, lamins A, B1, B2, and C, nucleophosmin (B23) and the epigenetic marker H4K20me3 by immunohistochemistry. RESULTS Two neuronal populations were found across AD stages, one is characterized by a significant increase of Lamin A expression, reinforced perinuclear Lamin B2, elevated expression of H4K20me3 and nuclear Tau loss, while neurons with nucleoplasmic Lamin B2 constitute a second population. CONCLUSIONS The abnormal cell cycle reentry in early AD implies a fundamental neuronal transformation. This implies the reorganization of the nucleo-cytoskeleton through the expression of the highly regulated Lamin A, heterochromatin repression and building of toxic neuronal tangles. This work demonstrates that nuclear Tau and lamin modifications in hippocampal neurons are crucial events in age-related neurodegeneration.
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Affiliation(s)
- Laura Gil
- Departamento de Genética, Escuela de Medicina, Universidad “Alfonso X el Sabio”, 28691 Madrid, Spain; (L.G.)
| | - Sandra A. Niño
- Departamento de Bioquímica, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí 78210, Mexico
| | - Erika Chi-Ahumada
- Departamento de Bioquímica, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí 78210, Mexico
| | | | - Carmen Guerrero
- Banco de cerebros (Biobanco), Hospital Universitario Fundación Alcorcón, Alcorcón, 28922 Madrid, Spain
| | - Ana Belén Rebolledo
- Banco de cerebros (Biobanco), Hospital Universitario Fundación Alcorcón, Alcorcón, 28922 Madrid, Spain
| | - José A. Arias
- Departamento de Genética, Escuela de Medicina, Universidad “Alfonso X el Sabio”, 28691 Madrid, Spain; (L.G.)
| | - María E. Jiménez-Capdeville
- Departamento de Bioquímica, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí 78210, Mexico
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Meinke P, Kerr ARW, Czapiewski R, de Las Heras JI, Dixon CR, Harris E, Kölbel H, Muntoni F, Schara U, Straub V, Schoser B, Wehnert M, Schirmer EC. A multistage sequencing strategy pinpoints novel candidate alleles for Emery-Dreifuss muscular dystrophy and supports gene misregulation as its pathomechanism. EBioMedicine 2019; 51:102587. [PMID: 31862442 PMCID: PMC7000448 DOI: 10.1016/j.ebiom.2019.11.048] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 11/18/2019] [Accepted: 11/26/2019] [Indexed: 12/27/2022] Open
Abstract
Background As genome-wide approaches prove difficult with genetically heterogeneous orphan diseases, we developed a new approach to identify candidate genes. We applied this to Emery-Dreifuss muscular dystrophy (EDMD), characterised by early onset contractures, slowly progressive muscular wasting, and life-threatening heart conduction disturbances with wide intra- and inter-familial clinical variability. Roughly half of EDMD patients are linked to six genes encoding nuclear envelope proteins, but the disease mechanism remains unclear because the affected proteins function in both cell mechanics and genome regulation. Methods A primer library was generated to test for mutations in 301 genes from four categories: (I) all known EDMD-linked genes; (II) genes mutated in related muscular dystrophies; (III) candidates generated by exome sequencing in five families; (IV) functional candidates — other muscle nuclear envelope proteins functioning in mechanical/genome processes affected in EDMD. This was used to sequence 56 unlinked patients with EDMD-like phenotype. Findings Twenty-one patients could be clearly assigned: 18 with mutations in genes of similar muscular dystrophies; 3 with previously missed mutations in EDMD-linked genes. The other categories yielded novel candidate genes, most encoding nuclear envelope proteins with functions in gene regulation. Interpretation Our multi-pronged approach identified new disease alleles and many new candidate EDMD genes. Their known functions strongly argue the EDMD pathomechanism is from altered gene regulation and mechanotransduction due to connectivity of candidates from the nuclear envelope to the plasma membrane. This approach highlights the value of testing for related diseases using primer libraries and may be applied for other genetically heterogeneous orphan diseases. Funding The Wellcome Trust, Muscular Dystrophy UK, Medical Research Council, European Community's Seventh Framework Programme “Integrated European –omics research project for diagnosis and therapy in rare neuromuscular and neurodegenerative diseases (NEUROMICS)”.
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Affiliation(s)
- Peter Meinke
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK; Friedrich Baur Institute at the Department of Neurology, University Hospital, LMU Munich, Germany
| | - Alastair R W Kerr
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Rafal Czapiewski
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | | | - Charles R Dixon
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Elizabeth Harris
- John Walton Muscular Dystrophy Research Centre, Newcastle University and Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Heike Kölbel
- Department of Pediatric Neurology, Developmental Neurology and Social Pediatrics, University of Essen, Germany
| | - Francesco Muntoni
- Dubowitz Neuromuscular Centre, University College London Great Ormond Street Institute of Child Health, London, UK; 1 NIHR Great Ormond Street Hospital Biomedical Research Centre, Great Ormond Street Institute of Child Health, University College London, & Great Ormond Street Hospital Trust, London, UK
| | - Ulrike Schara
- Department of Pediatric Neurology, Developmental Neurology and Social Pediatrics, University of Essen, Germany
| | - Volker Straub
- John Walton Muscular Dystrophy Research Centre, Newcastle University and Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Benedikt Schoser
- Friedrich Baur Institute at the Department of Neurology, University Hospital, LMU Munich, Germany
| | - Manfred Wehnert
- Institute of Human Genetics, University of Greifswald (retired), Greifswald, Germany
| | - Eric C Schirmer
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK.
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Perepelina K, Klauzen P, Kostareva A, Malashicheva A. Tissue-Specific Influence of Lamin A Mutations on Notch Signaling and Osteogenic Phenotype of Primary Human Mesenchymal Cells. Cells 2019; 8:cells8030266. [PMID: 30901896 PMCID: PMC6468400 DOI: 10.3390/cells8030266] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 03/16/2019] [Accepted: 03/19/2019] [Indexed: 12/19/2022] Open
Abstract
Lamin A is involved in many cellular functions due to its ability to bind chromatin and transcription factors and affect their properties. Mutations of LMNA gene encoding lamin A affect the differentiation capacity of stem cells, but the mechanisms of this influence remain largely unclear. We and others have reported recently an interaction of lamin A with Notch pathway, which is among the main developmental regulators of cellular identity. The aim of this study was to explore the influence of LMNA mutations on the proosteogenic response of human cells of mesenchymal origin and to further explore the interaction of LMNA with Notch pathway. Mutations R527C and R471C in LMNA are associated with mandibuloacral dysplasia type A, a highly penetrant disease with a variety of abnormalities involving bone development. We used lentiviral constructs bearing mutations R527C and R471C and explored its influence on proosteogenic phenotype expression and Notch pathway activity in four types of human cells: umbilical vein endothelial cells (HUVEC), cardiac mesenchymal cells (HCMC), aortic smooth muscle cells (HASMC), and aortic valve interstitial cells (HAVIC). The proosteogenic response of the cells was induced by the addition of either LPS or specific effectors of osteogenic differentiation to the culture medium; phenotype was estimated by the expression of osteogenic markers by qPCR; activation of Notch was assessed by expression of Notch-related and Notch-responsive genes by qPCR and by activation of a luciferase CSL-reporter construct. Overall, we observed different reactivity of all four cell lineages to the stimulation with either LPS or osteogenic factors. R527C had a stronger influence on the proosteogenic phenotype. We observed the inhibiting action of LMNA R527C on osteogenic differentiation in HCMC in the presence of activated Notch signaling, while LMNA R527C caused the activation of osteogenic differentiation in HAVIC in the presence of activated Notch signaling. Our results suggest that the effect of a LMNA mutation is strongly dependent not only on a specific mutation itself, but also might be influenced by the intrinsic molecular context of a cell lineage.
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Affiliation(s)
- Kseniya Perepelina
- Almazov National Medical Research Centre, 2 Akkuratova Str., St-Petersburg 197341, Russia.
- St-Petersburg State University, 7-9, Universitetskaya nab., St-Petersburg 199034, Russia.
| | - Polina Klauzen
- Almazov National Medical Research Centre, 2 Akkuratova Str., St-Petersburg 197341, Russia.
- St-Petersburg State University, 7-9, Universitetskaya nab., St-Petersburg 199034, Russia.
- Institute of Cytology, Russian Academy of Sciences, 4 Tikhoretsky Ave., St-Petersburg 194064, Russia.
| | - Anna Kostareva
- Almazov National Medical Research Centre, 2 Akkuratova Str., St-Petersburg 197341, Russia.
- St-Petersburg State University, 7-9, Universitetskaya nab., St-Petersburg 199034, Russia.
| | - Anna Malashicheva
- Almazov National Medical Research Centre, 2 Akkuratova Str., St-Petersburg 197341, Russia.
- St-Petersburg State University, 7-9, Universitetskaya nab., St-Petersburg 199034, Russia.
- Institute of Cytology, Russian Academy of Sciences, 4 Tikhoretsky Ave., St-Petersburg 194064, Russia.
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Skeletal Muscle Dystrophy mutant of lamin A alters the structure and dynamics of the Ig fold domain. Sci Rep 2018; 8:13793. [PMID: 30218058 PMCID: PMC6138676 DOI: 10.1038/s41598-018-32227-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 08/21/2018] [Indexed: 12/15/2022] Open
Abstract
Mutations in the different domains of A-type lamin proteins cause a diverse plethora of diseases collectively termed as laminopathies which can affect multiple organs. Ig fold is one such domain of lamin A which is implicated in numerous nuclear interactions wherein the mutations lead to different laminopathies. W514R is one such mutation in the Ig fold which leads to severe phenotypes in Skeletal Muscle Dystrophy (SMD) which is a class of laminopathies. In this report, we elucidated gross alterations in structure and dynamics at the level of individual amino acids. These studies indicate altered conformational features of residues in the close vicinity of W514. Imaging of mammalian cells transfected with the mutant have shown distinct perturbation of the nuclear meshwork with concomitant alteration in nuclear interactions as a result of increased oligomerization of Ig W514R. Hence, this novel approach of amalgamating theoretical and experimental procedures to predict the severity of a mutant in the context of laminopathies could be extended for numerous lamin A mutants.
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Perovanovic J, Dell'Orso S, Gnochi VF, Jaiswal JK, Sartorelli V, Vigouroux C, Mamchaoui K, Mouly V, Bonne G, Hoffman EP. Laminopathies disrupt epigenomic developmental programs and cell fate. Sci Transl Med 2017; 8:335ra58. [PMID: 27099177 DOI: 10.1126/scitranslmed.aad4991] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 02/28/2016] [Indexed: 12/12/2022]
Abstract
The nuclear envelope protein lamin A is encoded by thelamin A/C(LMNA) gene, which can contain missense mutations that cause Emery-Dreifuss muscular dystrophy (EDMD) (p.R453W). We fused mutated forms of the lamin A protein to bacterial DNA adenine methyltransferase (Dam) to define euchromatic-heterochromatin (epigenomic) transitions at the nuclear envelope during myogenesis (using DamID-seq). Lamin A missense mutations disrupted appropriate formation of lamin A-associated heterochromatin domains in an allele-specific manner-findings that were confirmed by chromatin immunoprecipitation-DNA sequencing (ChIP-seq) in murine H2K cells and DNA methylation studies in fibroblasts from muscular dystrophy patient who carried a distinctLMNAmutation (p.H222P). Observed perturbations of the epigenomic transitions included exit from pluripotency and cell cycle programs [euchromatin (open, transcribed) to heterochromatin (closed, silent)], as well as induction of myogenic loci (heterochromatin to euchromatin). In muscle biopsies from patients with either a gain- or change-of-functionLMNAgene mutation or a loss-of-function mutation in theemeringene, both of which cause EDMD, we observed inappropriate loss of heterochromatin formation at theSox2pluripotency locus, which was associated with persistent mRNA expression ofSox2 Overexpression ofSox2inhibited myogenic differentiation in human immortalized myoblasts. Our findings suggest that nuclear envelopathies are disorders of developmental epigenetic programming that result from altered formation of lamina-associated domains.
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Affiliation(s)
- Jelena Perovanovic
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC 20010, USA. Department of Integrative Systems Biology, The George Washington University School of Medicine and Health Sciences, Washington, DC 20010, USA
| | - Stefania Dell'Orso
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20852, USA
| | - Viola F Gnochi
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC 20010, USA
| | - Jyoti K Jaiswal
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC 20010, USA. Department of Integrative Systems Biology, The George Washington University School of Medicine and Health Sciences, Washington, DC 20010, USA
| | - Vittorio Sartorelli
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20852, USA
| | - Corinne Vigouroux
- Assistance Publique-Hôpitaux de Paris (AP-HP), Hôpital Saint-Antoine, Laboratoire Commun de Biologie et Génétique Moléculaires, F-75012 Paris, France. INSERM UMR_S938, Centre de Recherche Saint-Antoine, F-75012 Paris, France. Sorbonne Universités, UPMC (Université Pierre et Marie Curie) Univ Paris 06, UMR_S938, F-75005 Paris, France. ICAN (Institute of Cardiometabolism and Nutrition), F-75013 Paris, France
| | - Kamel Mamchaoui
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, F-75013 Paris, France
| | - Vincent Mouly
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, F-75013 Paris, France
| | - Gisèle Bonne
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, F-75013 Paris, France
| | - Eric P Hoffman
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC 20010, USA. Department of Integrative Systems Biology, The George Washington University School of Medicine and Health Sciences, Washington, DC 20010, USA.
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Abstract
Skeletal muscle regeneration is an efficient stem cell-based repair system that ensures healthy musculature. For this repair system to function continuously throughout life, muscle stem cells must contribute to the process of myofiber repair as well as repopulation of the stem cell niche. The decision made by the muscle stem cells to commit to the muscle repair or to remain a stem cell depends upon patterns of gene expression, a process regulated at the epigenetic level. Indeed, it is well accepted that dynamic changes in epigenetic landscapes to control DNA accessibility and expression is a critical component during myogenesis for the effective repair of damaged muscle. Changes in the epigenetic landscape are governed by various posttranslational histone tail modifications, nucleosome repositioning, and DNA methylation events which collectively allow the control of changes in transcription networks during transitions of satellite cells from a dormant quiescent state toward terminal differentiation. This chapter focuses upon the specific epigenetic changes that occur during muscle stem cell-mediated regeneration to ensure myofiber repair and continuity of the stem cell compartment. Furthermore, we explore open questions in the field that are expected to be important areas of exploration as we move toward a more thorough understanding of the epigenetic mechanism regulating muscle regeneration.
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Affiliation(s)
- Daniel C L Robinson
- Sprott Centre for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada; University of Ottawa, Ottawa, ON, Canada
| | - Francis J Dilworth
- Sprott Centre for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada; University of Ottawa, Ottawa, ON, Canada.
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Jeru I, Vatier C, Vantyghem MC, Lascols O, Vigouroux C. LMNA-associated partial lipodystrophy: anticipation of metabolic complications. J Med Genet 2017; 54:413-416. [DOI: 10.1136/jmedgenet-2016-104437] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 03/24/2017] [Accepted: 03/27/2017] [Indexed: 11/04/2022]
Abstract
BackgroundType-2 familial partial lipodystrophy (FPLD2) is a rare autosomal dominant lipodystrophic disorder due to mutations inLMNAencoding lamin A/C, a key epigenetic regulator. FPLD2 severity is determined by the occurrence of metabolic complications, especially diabetes and hypertriglyceridaemia. We evaluated the disease history and severity over generations.MethodsThis retrospective study of the largest cohort of patients with FPLD2 reported to date investigates 85 patients from 24 families comprising three generations (G1: n=39; G2: n=41; G3: n=5).ResultsLipodystrophy appears with the same characteristics and at the same age in first generation (G1;18.6±1.5 years) and second generation (G2;15.9±0.8 years). Despite similar body mass index (23.7±0.6 vs 23.8±0.6 kg/m2), the mean delay between the onset of lipodystrophy and diabetes was far shorter in G2 (10.5±2.4 years) than in G1 (29.0±3.5 years) (p=0.0002). The same is true for the delay preceding hypertriglyceridaemia (G2: 4.5±1.4; G1: 19.3±3.2 years) (p=0.002), revealing an anticipation phenomenon. Observations in G3, and analysis within each family of disease history and diagnostic procedures, confirmed this result.ConclusionsThis study is a rare example of anticipation unrelated to a trinucleotide expansion. Discovery of this early occurrence of metabolic complications in young generations underlines the utility of presymptomatic genetic diagnosis, with careful metabolic screening and preventive lifestyle in all at-risk individuals.
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14
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Hieda M. Implications for Diverse Functions of the LINC Complexes Based on the Structure. Cells 2017; 6:cells6010003. [PMID: 28134781 PMCID: PMC5371868 DOI: 10.3390/cells6010003] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 01/15/2017] [Accepted: 01/17/2017] [Indexed: 12/18/2022] Open
Abstract
The linker of nucleoskeleton and cytoskeleton (LINC) complex is composed of the outer and inner nuclear membrane protein families Klarsicht, Anc-1, and Syne homology (KASH), and Sad1 and UNC-84 (SUN) homology domain proteins. Increasing evidence has pointed to diverse functions of the LINC complex, such as in nuclear migration, nuclear integrity, chromosome movement and pairing during meiosis, and mechanotransduction to the genome. In metazoan cells, the nuclear envelope possesses the nuclear lamina, which is a thin meshwork of intermediate filaments known as A-type and B-type lamins and lamin binding proteins. Both of lamins physically interact with the inner nuclear membrane spanning SUN proteins. The nuclear lamina has also been implicated in various functions, including maintenance of nuclear integrity, mechanotransduction, cellular signalling, and heterochromatin dynamics. Thus, it is clear that the LINC complex and nuclear lamins perform diverse but related functions. However, it is unknown whether the LINC complex-lamins interactions are involved in these diverse functions, and their regulation mechanism has thus far been elusive. Recent structural analysis suggested a dynamic nature of the LINC complex component, thus providing an explanation for LINC complex organization. This review, elaborating on the integration of crystallographic and biochemical data, helps to integrate this research to gain a better understanding of the diverse functions of the LINC complex.
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Affiliation(s)
- Miki Hieda
- Department of Medical Technology, Ehime Prefectural University of Health Sciences, Ehime 791-2101, Japan.
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15
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Abstract
The nucleus is separated from the cytosol by the nuclear envelope, which is a double lipid bilayer composed of the outer nuclear membrane and the inner nuclear membrane. The intermediate filament proteins lamin A, lamin B, and lamin C form a network underlying the inner nuclear membrane. This proteinaceous network provides the nucleus with its strength, rigidity, and elasticity. Positioned within the inner nuclear membrane are more than 150 inner nuclear membrane proteins, many of which interact directly with lamins and require lamins for their inner nuclear membrane localization. Inner nuclear membrane proteins and the nuclear lamins define the nuclear lamina. These inner nuclear membrane proteins have tissue-specific expression and diverse functions including regulating cytoskeletal organization, nuclear architecture, cell cycle dynamics, and genomic organization. Loss or mutations in lamins and inner nuclear membrane proteins cause a wide spectrum of diseases. Here, I will review the functions of the well-studied nuclear lamina proteins and the diseases associated with loss or mutations in these proteins. © 2016 American Physiological Society. Compr Physiol 6:1655-1674, 2016.
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Affiliation(s)
- James M. Holaska
- Department of Pharmaceutical Sciences, University of the Sciences, Philadelphia, Pennsylvania, USA
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16
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Association of lamin A/C with muscle gene-specific promoters in myoblasts. Biochem Biophys Rep 2015; 4:76-82. [PMID: 29124189 PMCID: PMC5668900 DOI: 10.1016/j.bbrep.2015.08.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 08/10/2015] [Accepted: 08/26/2015] [Indexed: 11/20/2022] Open
Abstract
The A-type and B-type lamins form a filamentous meshwork underneath the inner nuclear membrane called the nuclear lamina, which is an important component of nuclear architecture in metazoan cells. The lamina interacts with large, mostly repressive chromatin domains at the nuclear periphery. In addition, genome–lamina interactions also involve dynamic association of lamin A/C with gene promoters in adipocytes. Mutations in the human lamin A gene cause a spectrum of hereditary diseases called the laminopathies which affect muscle, cardiac and adipose tissues. Since most mutations in lamin A/C affect skeletal muscle, we investigated lamin–chromatin interactions at promoters of muscle specific genes in both muscle and non-muscle cell lines by ChIP-qPCR. We observed that lamin A/C was specifically associated with promoter regions of muscle genes in myoblasts but not in fibroblasts. Lamin A/C dissociated from the promoter regions of the differentiation specific MyoD, myogenin and muscle creatine kinase genes when myoblasts were induced to differentiate. In the promoter regions of the myogenin and MyoD genes, the binding of lamin A/C in myoblasts inversely correlated with the active histone mark, H3K4me3. Lamin A/C binding on muscle genes was reduced and differentiation potential was enhanced on treatment of myoblasts with a histone deacetylase inhibitor. These findings suggest a role for lamina–chromatin interactions in muscle differentiation and have important implications for the pathological mechanisms of striated muscle associated laminopathies. Lamina–chromatin interactions are important for nuclear processes. We show lamin A/C binding to promoters of muscle genes in myoblasts. Lamin A/C binding is reduced upon myoblast differentiation. Lamin A/C binding inversely correlates with active histone marks on muscle genes. Our findings suggest that lamin A/C binding to promoters is cell-type specific.
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17
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Camozzi D, Capanni C, Cenni V, Mattioli E, Columbaro M, Squarzoni S, Lattanzi G. Diverse lamin-dependent mechanisms interact to control chromatin dynamics. Focus on laminopathies. Nucleus 2015; 5:427-40. [PMID: 25482195 PMCID: PMC4164485 DOI: 10.4161/nucl.36289] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Interconnected functional strategies govern chromatin dynamics in eukaryotic cells. In this context, A and B type lamins, the nuclear intermediate filaments, act on diverse platforms involved in tissue homeostasis. On the nuclear side, lamins elicit large scale or fine chromatin conformational changes, affect DNA damage response factors and transcription factor shuttling. On the cytoplasmic side, bridging-molecules, the LINC complex, associate with lamins to coordinate chromatin dynamics with cytoskeleton and extra-cellular signals.
Consistent with such a fine tuning, lamin mutations and/or defects in their expression or post-translational processing, as well as mutations in lamin partner genes, cause a heterogeneous group of diseases known as laminopathies. They include muscular dystrophies, cardiomyopathy, lipodystrophies, neuropathies, and progeroid syndromes. The study of chromatin dynamics under pathological conditions, which is summarized in this review, is shedding light on the complex and fascinating role of the nuclear lamina in chromatin regulation.
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Affiliation(s)
- Daria Camozzi
- a CNR Institute for Molecular Genetics; Unit of Bologna and SC Laboratory of Musculoskeletal Cell Biology; Rizzoli Orthopedic Institute; Bologna, Italy
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18
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Malashicheva A, Bogdanova M, Zabirnyk A, Smolina N, Ignatieva E, Freilikhman O, Fedorov A, Dmitrieva R, Sjöberg G, Sejersen T, Kostareva A. Various lamin A/C mutations alter expression profile of mesenchymal stem cells in mutation specific manner. Mol Genet Metab 2015; 115:118-27. [PMID: 25982065 DOI: 10.1016/j.ymgme.2015.04.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 04/27/2015] [Accepted: 04/28/2015] [Indexed: 12/31/2022]
Abstract
Various mutations in LMNA gene, encoding for nuclear lamin A/C protein, lead to laminopathies and contribute to over ten human disorders, mostly affecting tissues of mesenchymal origin such as fat tissue, muscle tissue, and bones. Recently it was demonstrated that lamins not only play a structural role providing communication between extra-nuclear structures and components of cell nucleus but also control cell fate and differentiation. In our study we assessed the effect of various LMNA mutations on the expression profile of mesenchymal multipotent stem cells (MMSC) during adipogenic and osteogenic differentiation. We used lentiviral approach to modify human MMSC with LMNA-constructs bearing mutations associated with different laminopathies--G465D, R482L, G232E, R527C, and R471C. The impact of various mutations on MMSC differentiation properties and expression profile was assessed by colony-forming unit analysis, histological staining, expression of the key differentiation markers promoting adipogenesis and osteogenesis followed by the analysis of the whole set of genes involved in lineage-specific differentiation using PCR expression arrays. We demonstrate that various LMNA mutations influence the differentiation efficacy of MMSC in mutation-specific manner. Each LMNA mutation promotes a unique expression pattern of genes involved in a lineage-specific differentiation and this pattern is shared by the phenotype-specific mutations.
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Affiliation(s)
- Anna Malashicheva
- Almazov Federal Medical Research Centre, St. Petersburg, Russia; St. Petersburg State University, St. Petersburg, Russia; ITMO University, Institute of translational Medicine, St. Petersburg, Russia
| | - Maria Bogdanova
- Almazov Federal Medical Research Centre, St. Petersburg, Russia; St. Petersburg State University, St. Petersburg, Russia
| | | | - Natalia Smolina
- Almazov Federal Medical Research Centre, St. Petersburg, Russia; Department of Woman and Child Health, Centre for Molecular Medicine, Karolinska Institute, Stockholm, Sweden
| | - Elena Ignatieva
- Almazov Federal Medical Research Centre, St. Petersburg, Russia
| | | | - Anton Fedorov
- Almazov Federal Medical Research Centre, St. Petersburg, Russia
| | | | - Gunnar Sjöberg
- Department of Woman and Child Health, Centre for Molecular Medicine, Karolinska Institute, Stockholm, Sweden
| | - Thomas Sejersen
- Department of Woman and Child Health, Centre for Molecular Medicine, Karolinska Institute, Stockholm, Sweden
| | - Anna Kostareva
- Almazov Federal Medical Research Centre, St. Petersburg, Russia; Department of Woman and Child Health, Centre for Molecular Medicine, Karolinska Institute, Stockholm, Sweden; ITMO University, Institute of translational Medicine, St. Petersburg, Russia.
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19
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Crocetti S, Beyer C, Unternährer S, Benavides Damm T, Schade-Kampmann G, Hebeisen M, Di Berardino M, Fröhlich J, Franco-Obregón A. Impedance flow cytometry gauges proliferative capacity by detecting TRPC1 expression. Cytometry A 2014; 85:525-36. [DOI: 10.1002/cyto.a.22461] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 12/10/2013] [Accepted: 03/03/2014] [Indexed: 01/13/2023]
Affiliation(s)
| | - Christian Beyer
- Electromagnetics in Medicine and Biology Group, Laboratory for Electromagnetic Fields and Microwave Electronics; ETH Zürich Switzerland
| | | | - Tatiana Benavides Damm
- Institute for Biomechanics; ETH Zürich Switzerland
- CC Aerospace Biomedical Science & Technology, Space Biology Group, Luzern University of Applied Sciences and Arts; Hergiswil Switzerland
| | | | - Monika Hebeisen
- Leister Process Technologies; Axetris Division; Kaegiswil Switzerland
| | | | - Jürg Fröhlich
- Electromagnetics in Medicine and Biology Group, Laboratory for Electromagnetic Fields and Microwave Electronics; ETH Zürich Switzerland
| | - Alfredo Franco-Obregón
- Institute for Biomechanics; ETH Zürich Switzerland
- Department of Surgery; Yong Loo Lin School of Medicine, National University of Singapore; Singapore
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20
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Bindesbøll C, Berg O, Arntsen B, Nebb HI, Dalen KT. Fatty acids regulate perilipin5 in muscle by activating PPARδ. J Lipid Res 2013; 54:1949-63. [PMID: 23606724 DOI: 10.1194/jlr.m038992] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The surface of lipid droplets (LDs) in various cell types is coated with perilipin proteins encoded by the Plin genes. Perilipins regulate LD metabolism by selectively recruiting lipases and other proteins to LDs. We have studied the expression of perilipins in mouse muscle. The glycolytic fiber-enriched gastrocnemius muscle expresses predominantly Plin2-4. The oxidative fiber-enriched soleus muscle expresses Plin2-5. Expression of Plin2 and Plin4-5 is elevated in gastrocnemius and soleus muscles from mice fed a high-fat diet. This effect is preserved in peroxisome proliferator-activated receptor (PPAR)α-deficient mice. Mouse muscle derived C2C12 cells differentiated into glycolytic fibers increase transcription of these Plins when exposed to various long chain fatty acids (FAs). To understand how FAs regulate Plin genes, we used specific activators and antagonists against PPARs, Plin promoter reporter assays, chromatin immunoprecipitation, siRNA, and animal models. Our analyses demonstrate that FAs require PPARδ to induce transcription of Plin4 and Plin5. We further identify a functional PPAR binding site in the Plin5 gene and establish Plin5 as a novel direct PPARδ target in muscle. Our study reveals that muscle cells respond to elevated FAs by increasing transcription of several perilipin LD-coating proteins. This induction renders the muscle better equipped to sequester incoming FAs into cytosolic LDs.
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Affiliation(s)
- Christian Bindesbøll
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
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21
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Moindrot B, Bouvet P, Mongelard F. Chromatin structure and organization: the relation with gene expression during development and disease. Subcell Biochem 2013; 61:373-396. [PMID: 23150259 DOI: 10.1007/978-94-007-4525-4_16] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The elementary level of chromatin fiber, namely the nucleofilament, is known to undergo a hierarchical compaction leading to local chromatin loops, then chromatin domains and ultimately chromosome territories. These successive folding levels rely on the formation of chromatin loops ranging from few kb to some Mb. In addition to a packaging and structural role, the high-order organization of genomes functionally impacts on gene expression program. This review summarises to which extent each level of chromatin compaction does affect gene regulation. In addition, we point out the structural and functional changes observed in diseases. Emphasis will be mainly placed on the large-scale organization of the chromatin.
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Affiliation(s)
- Benoît Moindrot
- Laboratoire Joliot-Curie, Centre National de la Recherche Scientifique (CNRS)/Ecole Normale Supérieure de Lyon, Université de Lyon, 46 allée d'Italie, 69007, Lyon, France
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22
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Narula N, Favalli V, Tarantino P, Grasso M, Pilotto A, Bellazzi R, Serio A, Gambarin FI, Charron P, Meder B, Pinto Y, Elliott PM, Mogensen J, Bolognesi M, Bollati M, Arbustini E. Quantitative expression of the mutated lamin A/C gene in patients with cardiolaminopathy. J Am Coll Cardiol 2012; 60:1916-20. [PMID: 23062543 DOI: 10.1016/j.jacc.2012.05.059] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Revised: 05/23/2012] [Accepted: 05/28/2012] [Indexed: 01/19/2023]
Abstract
OBJECTIVES The authors sought to investigate the gene and protein expression in Lamin A/C (LMNA)-mutated dilated cardiolaminopathy (DCM) patients (DCM(LMNAMut)) versus LMNA-wild-type DCM (DCM(LMNAWT)), and normal controls (CTRL(LMNAWT)). BACKGROUND Dilated cardiolaminopathies are clinically characterized by high arrhythmogenic risk and caused by LMNA mutations. Little is known regarding quantitative gene expression (QGE) of the LMNA gene in blood and myocardium, as well as regarding myocardial expression of the lamin A/C protein. METHODS Using the comparative ΔΔCT method, we evaluated the QGE of LMNA (QGE(LMNA)) in peripheral blood and myocardial RNA from carriers of LMNA mutations, versus blood and myocardial samples from DCM(LMNAWT) patients and CTRL(LMNAWT) individuals. After generating reference values in normal controls, QGE(LMNA) was performed in 311 consecutive patients and relatives, blind to genotype, to assess the predictive value of QGE(LMNA) for the identification of mutation carriers. In parallel, Lamin A/C was investigated in myocardial samples from DCM(LMNAMut) versus DCM(LMNAWT) versus normal hearts (CTRL(LMNAWT)). RESULTS LMNA was significantly underexpressed in mRNA from peripheral blood and myocardium of DCM(LMNAMut) patients versus DCM(LMNAWT) and CTRL(LMNAWT). In 311 individuals, blind to genotype, the QGE(LMNA) showed 100% sensitivity and 87% specificity as a predictor of LMNA mutations. The receiver-operating characteristic curve analysis yielded an area under the curve of 0.957 (p < 0.001). Loss of protein in cardiomyocytes' nuclei was documented in DCM(LMNAMut) patients. CONCLUSIONS The reduced expression of LMNA gene in blood is a novel potential predictive biomarker for dilated cardiolaminopathies with parallel loss of protein expression in cardiomyocyte nuclei.
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Affiliation(s)
- Nupoor Narula
- Centre for Inherited Cardiovascular Diseases, Foundation IRCCS Policlinico San Matteo, University of Pavia, Piazzale Golgi 19, Pavia, Italy
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23
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Abstract
The lamins are the major architectural proteins of the animal cell nucleus. Lamins line the inside of the nuclear membrane, where they provide a platform for the binding of proteins and chromatin and confer mechanical stability. They have been implicated in a wide range of nuclear functions, including higher-order genome organization, chromatin regulation, transcription, DNA replication and DNA repair. The lamins are members of the intermediate filament (IF) family of proteins, which constitute a major component of the cytoskeleton. Lamins are the only nuclear IFs and are the ancestral founders of the IF protein superfamily. Lamins polymerize into fibers forming a complex protein meshwork in vivo and, like all IF proteins, have a tripartite structure with two globular head and tail domains flanking a central α-helical rod domain, which supports the formation of higher-order polymers. Mutations in lamins cause a large number of diverse human diseases, collectively known as the laminopathies, underscoring their functional importance.
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Affiliation(s)
- Travis A Dittmer
- National Cancer Institute, National Institutes of Health, Bethesda, MD 20896, USA.
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24
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Pasque V, Gillich A, Garrett N, Gurdon JB. Histone variant macroH2A confers resistance to nuclear reprogramming. EMBO J 2011; 30:2373-87. [PMID: 21552206 PMCID: PMC3116279 DOI: 10.1038/emboj.2011.144] [Citation(s) in RCA: 121] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 04/13/2011] [Indexed: 01/31/2023] Open
Abstract
Gurdon and collaborators report reversible X chromosome inactivation in epiblast stem cells (EpiSCs) that seems to be determined by macroH2A1 deposition. These findings are of rather general interest as they highlight the epigenetic state of repressed loci as determinant for reprogramming efficiency. How various layers of epigenetic repression restrict somatic cell nuclear reprogramming is poorly understood. The transfer of mammalian somatic cell nuclei into Xenopus oocytes induces transcriptional reprogramming of previously repressed genes. Here, we address the mechanisms that restrict reprogramming following nuclear transfer by assessing the stability of the inactive X chromosome (Xi) in different stages of inactivation. We find that the Xi of mouse post-implantation-derived epiblast stem cells (EpiSCs) can be reversed by nuclear transfer, while the Xi of differentiated or extraembryonic cells is irreversible by nuclear transfer to oocytes. After nuclear transfer, Xist RNA is lost from chromatin of the Xi. Most epigenetic marks such as DNA methylation and Polycomb-deposited H3K27me3 do not explain the differences between reversible and irreversible Xi. Resistance to reprogramming is associated with incorporation of the histone variant macroH2A, which is retained on the Xi of differentiated cells, but absent from the Xi of EpiSCs. Our results uncover the decreased stability of the Xi in EpiSCs, and highlight the importance of combinatorial epigenetic repression involving macroH2A in restricting transcriptional reprogramming by oocytes.
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Affiliation(s)
- Vincent Pasque
- Wellcome Trust Cancer Research UK Gurdon Institute, Cambridge, UK.
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25
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Gnocchi VF, Scharner J, Huang Z, Brady K, Lee JS, White RB, Morgan JE, Sun YB, Ellis JA, Zammit PS. Uncoordinated transcription and compromised muscle function in the lmna-null mouse model of Emery- Emery-Dreyfuss muscular dystrophy. PLoS One 2011; 6:e16651. [PMID: 21364987 PMCID: PMC3043058 DOI: 10.1371/journal.pone.0016651] [Citation(s) in RCA: 25] [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: 09/28/2010] [Accepted: 12/23/2010] [Indexed: 12/15/2022] Open
Abstract
LMNA encodes both lamin A and C: major components of the nuclear lamina. Mutations in LMNA underlie a range of tissue-specific degenerative diseases, including those that affect skeletal muscle, such as autosomal-Emery-Dreifuss muscular dystrophy (A-EDMD) and limb girdle muscular dystrophy 1B. Here, we examine the morphology and transcriptional activity of myonuclei, the structure of the myotendinous junction and the muscle contraction dynamics in the lmna-null mouse model of A-EDMD. We found that there were fewer myonuclei in lmna-null mice, of which ∼50% had morphological abnormalities. Assaying transcriptional activity by examining acetylated histone H3 and PABPN1 levels indicated that there was a lack of coordinated transcription between myonuclei lacking lamin A/C. Myonuclei with abnormal morphology and transcriptional activity were distributed along the length of the myofibre, but accumulated at the myotendinous junction. Indeed, in addition to the presence of abnormal myonuclei, the structure of the myotendinous junction was perturbed, with disorganised sarcomeres and reduced interdigitation with the tendon, together with lipid and collagen deposition. Functionally, muscle contraction became severely affected within weeks of birth, with specific force generation dropping as low as ∼65% and ∼27% of control values in the extensor digitorum longus and soleus muscles respectively. These observations illustrate the importance of lamin A/C for correct myonuclear function, which likely acts synergistically with myotendinous junction disorganisation in the development of A-EDMD, and the consequential reduction in force generation and muscle wasting.
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MESH Headings
- Animals
- Cell Nucleus/metabolism
- Cell Nucleus/pathology
- Cell Nucleus/physiology
- Chromatin Assembly and Disassembly/genetics
- Chromatin Assembly and Disassembly/physiology
- Disease Models, Animal
- Growth and Development/genetics
- Intercellular Junctions/metabolism
- Intercellular Junctions/pathology
- Intercellular Junctions/ultrastructure
- Lamin Type A/genetics
- Lamin Type A/metabolism
- Lamin Type A/physiology
- Mice
- Mice, Knockout
- Muscle Fibers, Skeletal/metabolism
- Muscle Fibers, Skeletal/pathology
- Muscle Fibers, Skeletal/physiology
- Muscle Fibers, Skeletal/ultrastructure
- Muscle Weakness/genetics
- Muscle Weakness/pathology
- Muscles/metabolism
- Muscles/pathology
- Muscles/physiopathology
- Muscular Dystrophy, Emery-Dreifuss/genetics
- Muscular Dystrophy, Emery-Dreifuss/metabolism
- Muscular Dystrophy, Emery-Dreifuss/pathology
- Muscular Dystrophy, Emery-Dreifuss/physiopathology
- RNA Processing, Post-Transcriptional/genetics
- RNA Processing, Post-Transcriptional/physiology
- Transcription, Genetic/physiology
- Weight Loss/genetics
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Affiliation(s)
- Viola F. Gnocchi
- The Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, Guy's Campus, London, United Kingdom
| | - Juergen Scharner
- The Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, Guy's Campus, London, United Kingdom
| | - Zhe Huang
- The Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, Guy's Campus, London, United Kingdom
| | - Ken Brady
- Centre for Ultrastructural Imaging, King's College London, New Hunt's House, Guy's Campus, London, United Kingdom
| | - Jaclyn S. Lee
- The Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, Guy's Campus, London, United Kingdom
| | - Robert B. White
- The Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, Guy's Campus, London, United Kingdom
| | - Jennifer E. Morgan
- The Dubowitz Neuromuscular Centre, Institute of Child Health, University College, London, United Kingdom
| | - Yin-Biao Sun
- The Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, Guy's Campus, London, United Kingdom
| | - Juliet A. Ellis
- The Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, Guy's Campus, London, United Kingdom
| | - Peter S. Zammit
- The Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, Guy's Campus, London, United Kingdom
- * E-mail:
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26
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Mattioli E, Columbaro M, Capanni C, Maraldi NM, Cenni V, Scotlandi K, Marino MT, Merlini L, Squarzoni S, Lattanzi G. Prelamin A-mediated recruitment of SUN1 to the nuclear envelope directs nuclear positioning in human muscle. Cell Death Differ 2011; 18:1305-15. [PMID: 21311568 DOI: 10.1038/cdd.2010.183] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Lamin A is a nuclear lamina constituent expressed in differentiated cells. Mutations in the LMNA gene cause several diseases, including muscular dystrophy and cardiomyopathy. Among the nuclear envelope partners of lamin A are Sad1 and UNC84 domain-containing protein 1 (SUN1) and Sad1 and UNC84 domain-containing protein 2 (SUN2), which mediate nucleo-cytoskeleton interactions critical to the anchorage of nuclei. In this study, we show that differentiating human myoblasts accumulate farnesylated prelamin A, which elicits upregulation and recruitment of SUN1 to the nuclear envelope and favors SUN2 enrichment at the nuclear poles. Indeed, impairment of prelamin A farnesylation alters SUN1 recruitment and SUN2 localization. Moreover, nuclear positioning in myotubes is severely affected in the absence of farnesylated prelamin A. Importantly, reduced prelamin A and SUN1 levels are observed in Emery-Dreifuss muscular dystrophy (EDMD) myoblasts, concomitant with altered myonuclear positioning. These results demonstrate that the interplay between SUN1 and farnesylated prelamin A contributes to nuclear positioning in human myofibers and may be implicated in pathogenetic mechanisms.
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Affiliation(s)
- E Mattioli
- Institute for Molecular Genetics, IGM-CNR, Unit of Bologna, Bologna, Italy
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27
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Choi J, Jang H, Kim H, Kim ST, Cho EJ, Youn HD. Histone demethylase LSD1 is required to induce skeletal muscle differentiation by regulating myogenic factors. Biochem Biophys Res Commun 2010; 401:327-32. [PMID: 20833138 DOI: 10.1016/j.bbrc.2010.09.014] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Accepted: 09/04/2010] [Indexed: 12/15/2022]
Abstract
During myogenesis, transcriptional activities of two major myogenic factors, MyoD and myocyte enhancer factor 2 (Mef2) are regulated by histone modifications that switch on and off the target genes. However, the transition mechanism from repression to activation modes of histones has not been defined. Here we identify that lysine specific demethylase 1, (LSD1) is responsible for removing the repressive histone codes during C2C12 mouse myoblast differentiation. The potent role of LSD1 is suggested by the increment of its expression level during myogenic differentiation. Moreover, by performing co-immunoprecipitation and ChIP assay, physically interaction of LSD1 with MyoD and Mef2 on the target promoters was identified. Their interactions were resulted in upregulation of the transcription activities shown with increased luciferase activity. Interruption of demethylase activity of LSD1 using shRNA or chemical inhibitor, pargyline, treatment led to aberrant histone codes on myogenic promoters during skeletal muscle differentiation. We also demonstrate that inhibition of LSD1 impairs C2C12 mouse myoblast differentiation. Our results show for the first time the regulatory mechanism of myogenesis involving histone demethylase. Altogether, the present study suggests a de-repression model and expands the understanding on the dynamic regulation of chromatin during myogenesis.
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Affiliation(s)
- Jinmi Choi
- National Research Laboratory for Metabolic Checkpoint, Departments of Biomedical Sciences and Biochemistry and Molecular Biology, Cancer Research Institute, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea
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Kelly RDW, Alberio R, Campbell KHS. A-type lamin dynamics in bovine somatic cell nuclear transfer embryos. Reprod Fertil Dev 2010; 22:956-65. [PMID: 20591330 DOI: 10.1071/rd09264] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2009] [Accepted: 01/20/2010] [Indexed: 01/29/2023] Open
Abstract
The persistence of A-type nuclear lamin in somatic cell nuclear transfer (SCNT) embryos has been proposed as a marker for incomplete nuclear reprogramming. Using monoclonal antibodies to A/C- (A/C-346 and A/C-131C3) and B-type lamin, we compared distribution during early development of bovine IVF, parthenogenetic and SCNT embryos. A/C-346 staining was observed in the pronuclei of IVF embryos and in nuclei at the two-cell stage, but was not detected in subsequent cleavage stages up to and including hatched blastocysts. In contrast, A/C-131C3 and anti-lamin B2 stained all preimplantation stage embryos. Parthenogenetic and SCNT embryos had similar staining patterns to IVF embryos for all three antibodies, demonstrating correct nuclear architecture reprogramming. Inhibiting protein synthesis with cycloheximide (CHX) in parthenogenetic and SCNT embryos did not affect lamin A/C localisation, suggesting that lamin A/C is maternal in origin. However, activation with CHX delayed lamin A/C incorporation compared with 6-dimethylaminopurine activation. In SCNT embryos, staining for both A/C- and B-type lamin was delayed compared with parthenotes, although lamin B2 incorporation preceded lamin A/C in both. In conclusion, the lamin A/C distribution in SCNT bovine embryos paralleled that of IVF and parthenogenetic controls and therefore is not a marker of incomplete reprogramming.
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Affiliation(s)
- Richard D W Kelly
- Animal Development and Biotechnology Group, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire, UK
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29
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PolyADP-ribosylation is required for pronuclear fusion during postfertilization in mice. PLoS One 2010; 5. [PMID: 20824066 PMCID: PMC2932744 DOI: 10.1371/journal.pone.0012526] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Accepted: 07/27/2010] [Indexed: 01/30/2023] Open
Abstract
Background During fertilization, pronuclear envelope breakdown (PNEB) is followed by the mingling of male and female genomes. Dynamic chromatin and protein rearrangements require posttranslational modification (PTM) for the postfertilization development. Methodology/Principal Findings Inhibition of poly(ADP-ribose) polymerase activity (PARylation) by either PJ-34 or 5-AIQ resulted in developmental arrest of fertilized embryos at the PNEB. PARylation inhibition affects spindle bundle formation and phosphorylation of Erk molecules of metaphase II (MII) unfertilized oocytes. We found a frequent appearance of multiple pronuclei (PN) in the PARylation-inhibited embryos, suggesting defective polymerization of tubulins. Attenuated phosphorylation of lamin A/C by PARylation was detected in the PARylation-inhibited embryos at PNEB. This was associated with sustained localization of heterodomain protein 1 (HP1) at the PN of the one-cell embryos arrested by PARylation inhibition. Conclusions/Significance Our findings indicate that PARylation is required for pronuclear fusion during postfertilization processes. These data further suggest that PARylation regulates protein dynamics essential for the beginning of mouse zygotic development. PARylation and its involving signal-pathways may represent potential targets as contraceptives.
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Qureshi IA, Mehler MF. Impact of nuclear organization and dynamics on epigenetic regulation in the central nervous system: implications for neurological disease states. Ann N Y Acad Sci 2010; 1204 Suppl:E20-37. [PMID: 20840166 PMCID: PMC2946117 DOI: 10.1111/j.1749-6632.2010.05718.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Epigenetic mechanisms that are highly responsive to interoceptive and environmental stimuli mediate the proper execution of complex genomic programs, such as cell type-specific gene transcription and posttranscriptional RNA processing, and are increasingly thought to be important for modulating the development, homeostasis, and plasticity of the central nervous system (CNS). These epigenetic processes include DNA methylation, histone modifications, and chromatin remodeling, all of which play roles in neural cellular diversity, connectivity, and plasticity. Further, large-scale transcriptomic analyses have revealed that the eukaryotic genome is pervasively transcribed, forming interleaved protein-coding RNAs and regulatory nonprotein-coding RNAs (ncRNAs), which act through a broad array of molecular mechanisms. Most of these ncRNAs are transcribed in a cell type- and developmental stage-specific manner in the CNS. A broad array of posttranscriptional processes, such as RNA editing and transport, can modulate the functions of both protein-coding RNAs and ncRNAs. Additional studies implicate nuclear organization and dynamics in mediating epigenetic regulation. The compartmentalization of DNA sequences and other molecular machinery into functional nuclear domains, such as transcription factories, Cajal bodies, promyelocytic leukemia nuclear bodies, nuclear speckles, and paraspeckles, some of which are found prominently in neural cells, is associated with regulation of transcriptional activity and posttranscriptional RNA processing. These observations suggest that genomic architecture and RNA biology in the CNS are much more complex and nuanced than previously appreciated. Increasing evidence now suggests that most, if not all, human CNS diseases are associated with either primary or secondary perturbations in one or more aspects of the epigenome. In this review, we provide an update of our emerging understanding of genomic architecture, RNA biology, and nuclear organization and highlight the interconnected roles that deregulation of these factors may play in diverse CNS disorders.
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Affiliation(s)
- Irfan A. Qureshi
- Rosyln and Leslie Goldstein Laboratory for Stem Cell Biology and Regenerative Medicine, Albert Einstein College of Medicine, Bronx, New York, NY
- Institute for Brain Disorders and Neural Regeneration, Albert Einstein College of Medicine, Bronx, New York, NY
- Department of Neurology, Albert Einstein College of Medicine, Bronx, New York, NY
- Rose F. Kennedy Center for Research on Intellectual and Developmental Disabilities, Albert Einstein College of Medicine, Bronx, New York, NY
| | - Mark F. Mehler
- Rosyln and Leslie Goldstein Laboratory for Stem Cell Biology and Regenerative Medicine, Albert Einstein College of Medicine, Bronx, New York, NY
- Institute for Brain Disorders and Neural Regeneration, Albert Einstein College of Medicine, Bronx, New York, NY
- Department of Neurology, Albert Einstein College of Medicine, Bronx, New York, NY
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, NY
- Department of Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, Bronx, New York, NY
- Rose F. Kennedy Center for Research on Intellectual and Developmental Disabilities, Albert Einstein College of Medicine, Bronx, New York, NY
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Delbarre E, Jacobsen BM, Reiner AH, Sørensen AL, Küntziger T, Collas P. Chromatin environment of histone variant H3.3 revealed by quantitative imaging and genome-scale chromatin and DNA immunoprecipitation. Mol Biol Cell 2010; 21:1872-84. [PMID: 20375147 PMCID: PMC2877645 DOI: 10.1091/mbc.e09-09-0839] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Histone variant H3.3 is loaded onto chromatin in a replication-independent manner, but the epigenetic environment of H3.3 is unclear. Quantitative imaging and chromatin immunoprecipitation show that in mesenchymal stem cells H3.3 targets lineage-priming genes with a potential for activation facilitated by a permissive chromatin environment. In contrast to canonical histones, histone variant H3.3 is incorporated into chromatin in a replication-independent manner. Posttranslational modifications of H3.3 have been identified; however, the epigenetic environment of incorporated H3.3 is unclear. We have investigated the genomic distribution of epitope-tagged H3.3 in relation to histone modifications, DNA methylation, and transcription in mesenchymal stem cells. Quantitative imaging at the nucleus level shows that H3.3, relative to replicative H3.2 or canonical H2B, is enriched in chromatin domains marked by histone modifications of active or potentially active genes. Chromatin immunoprecipitation of epitope-tagged H3.3 and array hybridization identified 1649 H3.3-enriched promoters, a fraction of which is coenriched in H3K4me3 alone or together with H3K27me3, whereas H3K9me3 is excluded, corroborating nucleus-level imaging data. H3.3-enriched promoters are predominantly CpG-rich and preferentially DNA methylated, relative to the proportion of methylated RefSeq promoters in the genome. Most but not all H3.3-enriched promoters are transcriptionally active, and coenrichment of H3.3 with repressive H3K27me3 correlates with an enhanced proportion of expressed genes carrying this mark. H3.3-target genes are enriched in mesodermal differentiation and signaling functions. Our data suggest that in mesenchymal stem cells, H3.3 targets lineage-priming genes with a potential for activation facilitated by H3K4me3 in facultative association with H3K27me3.
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Affiliation(s)
- Erwan Delbarre
- Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
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Abstract
A- and B-type lamins are the major intermediate filaments of the nucleus. Lamins engage in a plethora of stable and transient interactions, near the inner nuclear membrane and throughout the nucleus. Lamin-binding proteins serve an amazingly diverse range of functions. Numerous inner-membrane proteins help anchor lamin filaments to the nuclear envelope, serving as part of the nuclear "lamina" network that is essential for nuclear architecture and integrity. Certain lamin-binding proteins of the inner membrane bind partners in the outer membrane and mechanically link lamins to the cytoskeleton. Inside the nucleus, lamin-binding proteins appear to serve as the "adaptors" by which the lamina organizes chromatin, influences gene expression and epigenetic regulation, and modulates signaling pathways. Transient interactions of lamins with key components of the transcription and replication machinery may provide an additional level of regulation or support to these essential events.
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Affiliation(s)
- Katherine L Wilson
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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Wallace DC, Fan W. Energetics, epigenetics, mitochondrial genetics. Mitochondrion 2009; 10:12-31. [PMID: 19796712 DOI: 10.1016/j.mito.2009.09.006] [Citation(s) in RCA: 351] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2009] [Revised: 09/21/2009] [Accepted: 09/23/2009] [Indexed: 12/15/2022]
Abstract
The epigenome has been hypothesized to provide the interface between the environment and the nuclear DNA (nDNA) genes. Key factors in the environment are the availability of calories and demands on the organism's energetic capacity. Energy is funneled through glycolysis and mitochondrial oxidative phosphorylation (OXPHOS), the cellular bioenergetic systems. Since there are thousands of bioenergetic genes dispersed across the chromosomes and mitochondrial DNA (mtDNA), both cis and trans regulation of the nDNA genes is required. The bioenergetic systems convert environmental calories into ATP, acetyl-Coenzyme A (acetyl-CoA), s-adenosyl-methionine (SAM), and reduced NAD(+). When calories are abundant, ATP and acetyl-CoA phosphorylate and acetylate chromatin, opening the nDNA for transcription and replication. When calories are limiting, chromatin phosphorylation and acetylation are lost and gene expression is suppressed. DNA methylation via SAM can also be modulated by mitochondrial function. Phosphorylation and acetylation are also pivotal to regulating cellular signal transduction pathways. Therefore, bioenergetics provides the interface between the environment and the epigenome. Consistent with this conclusion, the clinical phenotypes of bioenergetic diseases are strikingly similar to those observed in epigenetic diseases (Angelman, Rett, Fragile X Syndromes, the laminopathies, cancer, etc.), and an increasing number of epigenetic diseases are being associated with mitochondrial dysfunction. This bioenergetic-epigenomic hypothesis has broad implications for the etiology, pathophysiology, and treatment of a wide range of common diseases.
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Affiliation(s)
- Douglas C Wallace
- Center for Molecular and Mitochondrial Medicine and Genetics (MAMMAG), University of California, Irvine, CA 92697-3940, USA.
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Kandert S, Wehnert M, Müller CR, Buendia B, Dabauvalle MC. Impaired nuclear functions lead to increased senescence and inefficient differentiation in human myoblasts with a dominant p.R545C mutation in the LMNA gene. Eur J Cell Biol 2009; 88:593-608. [PMID: 19589617 DOI: 10.1016/j.ejcb.2009.06.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2009] [Revised: 06/05/2009] [Accepted: 06/05/2009] [Indexed: 11/26/2022] Open
Abstract
We have studied myoblasts from a patient with a severe autosomal dominant Emery-Dreifuss muscular dystrophy (AD-EDMD) caused by an arginine 545 to cystein point mutation (p.R545C) in the carboxy-terminal domain of the lamin A/C gene. This mutation has pleiotropic cellular effects on these myoblasts as demonstrated by nuclear structural defects, exhibiting lobulations which increase with cell passages in culture. The organization of both lamin A/C and its inner nuclear membrane partner emerin are altered, eventually showing a honeycomb pattern upon immunofluorescence microscopy. In addition, the distribution of histone H3 trimethylated at lysine 27 and of phosphorylated RNA polymerase II, markers of inactive and active chromatin domains, respectively, are altered suggesting an impact on gene expression. Patient myoblasts also presented a high index of senescence in ex vivo culture. Moreover, our data show for the first time in an AD-EDMD context that the 20S core particle of the proteasome was inactivated. With cell passages, the 20S core protein progressively accumulated into discrete nuclear foci that largely colocalized with promyelocytic leukemia (PML) bodies while p21 accumulated throughout the nuclear compartment. Proteasome inactivation has been linked to normal cellular ageing. Our data indicate that it may also contribute to premature senescence in AD-EDMD patient myoblasts. Finally, when transferred to low-serum medium, patient myoblasts were deficient in ex vivo differentiation, as assessed by the absence of myotube formation and myogenin induction. Altogether, these data suggest that the LMNA mutation p.R545C impairs both proliferation and differentiation capacities of myoblasts as part of the pathogenesis of AD-EDMD.
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Affiliation(s)
- Sebastian Kandert
- Division of Electron Microscopy, Biocenter, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
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Dechat T, Adam SA, Goldman RD. Nuclear lamins and chromatin: when structure meets function. ADVANCES IN ENZYME REGULATION 2008; 49:157-66. [PMID: 19154754 PMCID: PMC3253622 DOI: 10.1016/j.advenzreg.2008.12.003] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Thomas Dechat
- Northwestern University Medical School, Department of Cell and Molecular Biology, Chicago, Illinois 60611, USA
| | - Stephen A. Adam
- Northwestern University Medical School, Department of Cell and Molecular Biology, Chicago, Illinois 60611, USA
| | - Robert D. Goldman
- Northwestern University Medical School, Department of Cell and Molecular Biology, Chicago, Illinois 60611, USA
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