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Storey EC, Holt I, Brown S, Synowsky S, Shirran S, Fuller HR. Proteomic characterization of human LMNA-related congenital muscular dystrophy muscle cells. Neuromuscul Disord 2024; 38:26-41. [PMID: 38554696 DOI: 10.1016/j.nmd.2024.03.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 03/08/2024] [Accepted: 03/11/2024] [Indexed: 04/02/2024]
Abstract
LMNA-related congenital muscular dystrophy (L-CMD) is caused by mutations in the LMNA gene, encoding lamin A/C. To further understand the molecular mechanisms of L-CMD, proteomic profiling using DIA mass spectrometry was conducted on immortalized myoblasts and myotubes from controls and L-CMD donors each harbouring a different LMNA mutation (R249W, del.32 K and L380S). Compared to controls, 124 and 228 differentially abundant proteins were detected in L-CMD myoblasts and myotubes, respectively, and were associated with enriched canonical pathways including synaptogenesis and necroptosis in myoblasts, and Huntington's disease and insulin secretion in myotubes. Abnormal nuclear morphology and reduced lamin A/C and emerin abundance was evident in all L-CMD cell lines compared to controls, while nucleoplasmic aggregation of lamin A/C was restricted to del.32 K cells, and mislocalization of emerin was restricted to R249W cells. Abnormal nuclear morphology indicates loss of nuclear lamina integrity as a common feature of L-CMD, likely rendering muscle cells vulnerable to mechanically induced stress, while differences between L-CMD cell lines in emerin and lamin A localization suggests that some molecular alterations in L-CMD are mutation specific. Nonetheless, identifying common proteomic alterations and molecular pathways across all three L-CMD lines has highlighted potential targets for the development of non-mutation specific therapies.
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Affiliation(s)
- Emily C Storey
- Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, SY10 7AG, UK; The School of Pharmacy and Bioengineering, Keele University, ST5 5BG, UK
| | - Ian Holt
- Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, SY10 7AG, UK; The School of Pharmacy and Bioengineering, Keele University, ST5 5BG, UK
| | - Sharon Brown
- Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, SY10 7AG, UK; The School of Pharmacy and Bioengineering, Keele University, ST5 5BG, UK
| | - Silvia Synowsky
- BSRC Mass Spectrometry and Proteomics Facility, University of St Andrews, KY16 9ST, UK
| | - Sally Shirran
- BSRC Mass Spectrometry and Proteomics Facility, University of St Andrews, KY16 9ST, UK
| | - Heidi R Fuller
- Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, SY10 7AG, UK; The School of Pharmacy and Bioengineering, Keele University, ST5 5BG, UK.
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2
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Genotype-Phenotype Correlations in Human Diseases Caused by Mutations of LINC Complex-Associated Genes: A Systematic Review and Meta-Summary. Cells 2022; 11:cells11244065. [PMID: 36552829 PMCID: PMC9777268 DOI: 10.3390/cells11244065] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 12/09/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
Mutations in genes encoding proteins associated with the linker of nucleoskeleton and cytoskeleton (LINC) complex within the nuclear envelope cause different diseases with varying phenotypes including skeletal muscle, cardiac, metabolic, or nervous system pathologies. There is some understanding of the structure of LINC complex-associated proteins and how they interact, but it is unclear how mutations in genes encoding them can cause the same disease, and different diseases with different phenotypes. Here, published mutations in LINC complex-associated proteins were systematically reviewed and analyzed to ascertain whether patterns exist between the genetic sequence variants and clinical phenotypes. This revealed LMNA is the only LINC complex-associated gene in which mutations commonly cause distinct conditions, and there are no clear genotype-phenotype correlations. Clusters of LMNA variants causing striated muscle disease are located in exons 1 and 6, and metabolic disease-associated LMNA variants are frequently found in the tail of lamin A/C. Additionally, exon 6 of the emerin gene, EMD, may be a mutation "hot-spot", and diseases related to SYNE1, encoding nesprin-1, are most often caused by nonsense type mutations. These results provide insight into the diverse roles of LINC-complex proteins in human disease and provide direction for future gene-targeted therapy development.
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3
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Preclinical Advances of Therapies for Laminopathies. J Clin Med 2021; 10:jcm10214834. [PMID: 34768351 PMCID: PMC8584472 DOI: 10.3390/jcm10214834] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 10/19/2021] [Accepted: 10/19/2021] [Indexed: 11/29/2022] Open
Abstract
Laminopathies are a group of rare disorders due to mutation in LMNA gene. Depending on the mutation, they may affect striated muscles, adipose tissues, nerves or are multisystemic with various accelerated ageing syndromes. Although the diverse pathomechanisms responsible for laminopathies are not fully understood, several therapeutic approaches have been evaluated in patient cells or animal models, ranging from gene therapies to cell and drug therapies. This review is focused on these therapies with a strong focus on striated muscle laminopathies and premature ageing syndromes.
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Volkening K, Farhan SMK, Kao J, Leystra-Lantz C, Ang LC, McIntyre A, Wang J, Hegele RA, Strong MJ. Evidence of synergism among three genetic variants in a patient with LMNA-related lipodystrophy and amyotrophic lateral sclerosis leading to a remarkable nuclear phenotype. Mol Cell Biochem 2021; 476:2633-2650. [PMID: 33661429 PMCID: PMC8192393 DOI: 10.1007/s11010-021-04103-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Accepted: 02/06/2021] [Indexed: 11/25/2022]
Abstract
Neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), can be clinically heterogeneous which may be explained by the co-inheritance of multiple genetic variants that modify the clinical course. In this study we examine variants in three genes in a family with one individual presenting with ALS and lipodystrophy. Sequencing revealed a p.Gly602Ser variant in LMNA, and two additional variants, one each in SETX (g.intron10-13delCTT) and FUS (p.Gly167_Gly168del). These latter genes have been linked to ALS. All family members were genotyped and each variant, and each combination of variants detected, were functionally evaluated in vitro regarding effects on cell survival, expression patterns and cellular phenotype. Muscle biopsy retrieved from the individual with ALS showed leakage of chromatin from the nucleus, a phenotype that was recapitulated in vitro with expression of all three variants simultaneously. Individually expressed variants gave cellular phenotypes there were unremarkable. Interestingly the FUS variant appears to be protective against the effects of the SETX and the LMNA variants on cell viability and may indicate loss of interaction of FUS with SETX and/or R-loops. We conclude that these findings support genetic modifications as an explanation of the clinical heterogeneity observed in human disease.
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Affiliation(s)
- Kathryn Volkening
- Molecular Medicine, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Sali M K Farhan
- Analytic and Translational Genetics Unit, Center for Genomic Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02114, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| | - Jessica Kao
- Molecular Medicine, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Cheryl Leystra-Lantz
- Molecular Medicine, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Lee Cyn Ang
- Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- Department of Pathology and Laboratory Medicine, London Health Sciences Centre-University Hospital, London, ON, Canada
| | - Adam McIntyre
- Blackburn Cardiovascular Genetics Lab, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Jian Wang
- Blackburn Cardiovascular Genetics Lab, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Robert A Hegele
- Department of Pathology and Laboratory Medicine, London Health Sciences Centre-University Hospital, London, ON, Canada
- Blackburn Cardiovascular Genetics Lab, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- Department of Biochemistry, Western University, London, ON, Canada
| | - Michael J Strong
- Molecular Medicine, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.
- Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.
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5
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Widyastuti HP, Norden-Krichmar TM, Grosberg A, Zaragoza MV. Gene expression profiling of fibroblasts in a family with LMNA-related cardiomyopathy reveals molecular pathways implicated in disease pathogenesis. BMC MEDICAL GENETICS 2020; 21:152. [PMID: 32698886 PMCID: PMC7374820 DOI: 10.1186/s12881-020-01088-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 07/06/2020] [Indexed: 12/22/2022]
Abstract
Background Intermediate filament proteins that construct the nuclear lamina of a cell include the Lamin A/C proteins encoded by the LMNA gene, and are implicated in fundamental processes such as nuclear structure, gene expression, and signal transduction. LMNA mutations predominantly affect mesoderm-derived cell lineages in diseases collectively termed as laminopathies that include dilated cardiomyopathy with conduction defects, different forms of muscular dystrophies, and premature aging syndromes as Hutchinson-Gilford Progeria Syndrome. At present, our understanding of the molecular mechanisms regulating tissue-specific manifestations of laminopathies are still limited. Methods To gain deeper insight into the molecular mechanism of a novel LMNA splice-site mutation (c.357-2A > G) in an affected family with cardiac disease, we conducted deep RNA sequencing and pathway analysis for nine fibroblast samples obtained from three patients with cardiomyopathy, three unaffected family members, and three unrelated, unaffected individuals. We validated our findings by quantitative PCR and protein studies. Results We identified eight significantly differentially expressed genes between the mutant and non-mutant fibroblasts, that included downregulated insulin growth factor binding factor protein 5 (IGFBP5) in patient samples. Pathway analysis showed involvement of the ERK/MAPK signaling pathway consistent with previous studies. We found no significant differences in gene expression for Lamin A/C and B-type lamins between the groups. In mutant fibroblasts, RNA-seq confirmed that only the LMNA wild type allele predominately was expressed, and Western Blot showed normal Lamin A/C protein levels. Conclusions IGFBP5 may contribute in maintaining signaling pathway homeostasis, which may lead to the absence of notable molecular and structural abnormalities in unaffected tissues such as fibroblasts. Compensatory mechanisms from other nuclear membrane proteins were not found. Our results also demonstrate that only one copy of the wild type allele is sufficient for normal levels of Lamin A/C protein to maintain physiological function in an unaffected cell type. This suggests that affected cell types such as cardiac tissues may be more sensitive to haploinsufficiency of Lamin A/C. These results provide insight into the molecular mechanism of disease with a possible explanation for the tissue specificity of LMNA-related dilated cardiomyopathy.
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Affiliation(s)
- Halida P Widyastuti
- UCI Cardiogenomics Program, Department of Pediatrics, Division of Genetics & Genomics and Department of Biological Chemistry, University of California, Irvine, School of Medicine, 2042 Hewitt Hall, Irvine, CA, 92697-3940, USA
| | - Trina M Norden-Krichmar
- Department of Epidemiology, University of California, Irvine, School of Medicine, 3062 Anteater Instruction and Research Building, Irvine, CA, 92697-7550, USA.
| | - Anna Grosberg
- Department of Biomedical Engineering and The Edwards Lifesciences Center for Advanced Cardiovascular Technology, University of California, Irvine, Irvine, California, USA
| | - Michael V Zaragoza
- UCI Cardiogenomics Program, Department of Pediatrics, Division of Genetics & Genomics and Department of Biological Chemistry, University of California, Irvine, School of Medicine, 2042 Hewitt Hall, Irvine, CA, 92697-3940, USA.
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6
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Vigouroux C, Guénantin AC, Vatier C, Capel E, Le Dour C, Afonso P, Bidault G, Béréziat V, Lascols O, Capeau J, Briand N, Jéru I. Lipodystrophic syndromes due to LMNA mutations: recent developments on biomolecular aspects, pathophysiological hypotheses and therapeutic perspectives. Nucleus 2019; 9:235-248. [PMID: 29578370 PMCID: PMC5973242 DOI: 10.1080/19491034.2018.1456217] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Mutations in LMNA, encoding A-type lamins, are responsible for laminopathies including muscular dystrophies, lipodystrophies, and premature ageing syndromes. LMNA mutations have been shown to alter nuclear structure and stiffness, binding to partners at the nuclear envelope or within the nucleoplasm, gene expression and/or prelamin A maturation. LMNA-associated lipodystrophic features, combining generalized or partial fat atrophy and metabolic alterations associated with insulin resistance, could result from altered adipocyte differentiation or from altered fat structure. Recent studies shed some light on how pathogenic A-type lamin variants could trigger lipodystrophy, metabolic complications, and precocious cardiovascular events. Alterations in adipose tissue extracellular matrix and TGF-beta signaling could initiate metabolic inflexibility. Premature senescence of vascular cells could contribute to cardiovascular complications. In affected families, metabolic alterations occur at an earlier age across generations, which could result from epigenetic deregulation induced by LMNA mutations. Novel cellular models recapitulating adipogenic developmental pathways provide scalable tools for disease modeling and therapeutic screening.
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Affiliation(s)
- Corinne Vigouroux
- a Sorbonne Université, Inserm UMR_S 938, Centre de Recherche Saint-Antoine, Institut Hospitalo-Universitaire de Cardio-métabolisme et Nutrition (ICAN) , Paris , France.,b Assistance Publique-Hôpitaux de Paris, Hôpital Saint-Antoine, Laboratoire Commun de Biologie et Génétique Moléculaires , Paris , France.,c Assistance Publique-Hôpitaux de Paris, Hôpital Saint-Antoine, Centre National de Référence des Pathologies Rares de l'Insulino-Sécrétion et de l'Insulino-Sensibilité (PRISIS), Service d'Endocrinologie, Diabétologie et Endocrinologie de la Reproduction , Paris , France
| | - Anne-Claire Guénantin
- a Sorbonne Université, Inserm UMR_S 938, Centre de Recherche Saint-Antoine, Institut Hospitalo-Universitaire de Cardio-métabolisme et Nutrition (ICAN) , Paris , France.,d Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus , Hinxton , UK
| | - Camille Vatier
- a Sorbonne Université, Inserm UMR_S 938, Centre de Recherche Saint-Antoine, Institut Hospitalo-Universitaire de Cardio-métabolisme et Nutrition (ICAN) , Paris , France.,c Assistance Publique-Hôpitaux de Paris, Hôpital Saint-Antoine, Centre National de Référence des Pathologies Rares de l'Insulino-Sécrétion et de l'Insulino-Sensibilité (PRISIS), Service d'Endocrinologie, Diabétologie et Endocrinologie de la Reproduction , Paris , France
| | - Emilie Capel
- a Sorbonne Université, Inserm UMR_S 938, Centre de Recherche Saint-Antoine, Institut Hospitalo-Universitaire de Cardio-métabolisme et Nutrition (ICAN) , Paris , France
| | - Caroline Le Dour
- a Sorbonne Université, Inserm UMR_S 938, Centre de Recherche Saint-Antoine, Institut Hospitalo-Universitaire de Cardio-métabolisme et Nutrition (ICAN) , Paris , France
| | - Pauline Afonso
- a Sorbonne Université, Inserm UMR_S 938, Centre de Recherche Saint-Antoine, Institut Hospitalo-Universitaire de Cardio-métabolisme et Nutrition (ICAN) , Paris , France
| | - Guillaume Bidault
- a Sorbonne Université, Inserm UMR_S 938, Centre de Recherche Saint-Antoine, Institut Hospitalo-Universitaire de Cardio-métabolisme et Nutrition (ICAN) , Paris , France.,e University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital , Cambridge CB2 0QQ , UK
| | - Véronique Béréziat
- a Sorbonne Université, Inserm UMR_S 938, Centre de Recherche Saint-Antoine, Institut Hospitalo-Universitaire de Cardio-métabolisme et Nutrition (ICAN) , Paris , France
| | - Olivier Lascols
- a Sorbonne Université, Inserm UMR_S 938, Centre de Recherche Saint-Antoine, Institut Hospitalo-Universitaire de Cardio-métabolisme et Nutrition (ICAN) , Paris , France.,b Assistance Publique-Hôpitaux de Paris, Hôpital Saint-Antoine, Laboratoire Commun de Biologie et Génétique Moléculaires , Paris , France
| | - Jacqueline Capeau
- a Sorbonne Université, Inserm UMR_S 938, Centre de Recherche Saint-Antoine, Institut Hospitalo-Universitaire de Cardio-métabolisme et Nutrition (ICAN) , Paris , France
| | - Nolwenn Briand
- a Sorbonne Université, Inserm UMR_S 938, Centre de Recherche Saint-Antoine, Institut Hospitalo-Universitaire de Cardio-métabolisme et Nutrition (ICAN) , Paris , France.,f Department of Molecular Medicine , Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo , Blindern , Oslo , Norway
| | - Isabelle Jéru
- a Sorbonne Université, Inserm UMR_S 938, Centre de Recherche Saint-Antoine, Institut Hospitalo-Universitaire de Cardio-métabolisme et Nutrition (ICAN) , Paris , France.,b Assistance Publique-Hôpitaux de Paris, Hôpital Saint-Antoine, Laboratoire Commun de Biologie et Génétique Moléculaires , Paris , France
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7
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van Tienen FHJ, Lindsey PJ, Kamps MAF, Krapels IP, Ramaekers FCS, Brunner HG, van den Wijngaard A, Broers JLV. Assessment of fibroblast nuclear morphology aids interpretation of LMNA variants. Eur J Hum Genet 2018; 27:389-399. [PMID: 30420677 DOI: 10.1038/s41431-018-0294-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 10/12/2018] [Accepted: 10/16/2018] [Indexed: 01/26/2023] Open
Abstract
The phenotypic heterogeneity of Lamin A/C (LMNA) variants renders it difficult to classify them. As a consequence, many LMNA variants are classified as variant of unknown significance (VUS). A number of studies reported different types of visible nuclear abnormalities in LMNA-variant carriers, such as herniations, honeycomb-like structures and irregular Lamin staining. In this study, we used lamin A/C immunostaining and nuclear DAPI staining to assess the number and type of nuclear abnormalities in primary dermal fibroblast cultures of laminopathy patients and healthy controls. The total number of abnormal nuclei, which includes herniations, honeycomb-structures, and donut-like nuclei, was found to be the most discriminating parameter between laminopathy and control cell cultures. The percentage abnormal nuclei was subsequently scored in fibroblasts of 28 LMNA variant carriers, ranging from (likely) benign to (likely) pathogenic variant. Using this method, 27 out of 28 fibroblast cell cultures could be classified as either normal (n = 14) or laminopathy (n = 13) and no false positive results were obtained. The obtained specificity was 100% (CI 40-100%) and sensitivity 77% (46-95%). We conclude that assessing the percentage of abnormal nuclei is a quick and reliable method, which aids classification or confirms pathogenicity of identified LMNA variants causing formation of aberrant lamin A/C protein.
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Affiliation(s)
- Florence H J van Tienen
- Department of Clinical Genetics, Maastricht University Medical Centre, Maastricht, The Netherlands. .,GROW-School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, The Netherlands.
| | - Patrick J Lindsey
- Department of Genetics and Cell Biology, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Miriam A F Kamps
- GROW-School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, The Netherlands.,Department of Genetics and Cell Biology, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Ingrid P Krapels
- Department of Clinical Genetics, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Frans C S Ramaekers
- GROW-School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, The Netherlands.,Department of Genetics and Cell Biology, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Han G Brunner
- Department of Clinical Genetics, Maastricht University Medical Centre, Maastricht, The Netherlands.,Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Arthur van den Wijngaard
- Department of Clinical Genetics, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Jos L V Broers
- Department of Genetics and Cell Biology, Maastricht University Medical Centre, Maastricht, The Netherlands.,CARIM-School for Cardiovascular Diseases, Maastricht University Medical Centre, Maastricht, The Netherlands
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8
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Steele-Stallard HB, Pinton L, Sarcar S, Ozdemir T, Maffioletti SM, Zammit PS, Tedesco FS. Modeling Skeletal Muscle Laminopathies Using Human Induced Pluripotent Stem Cells Carrying Pathogenic LMNA Mutations. Front Physiol 2018; 9:1332. [PMID: 30405424 PMCID: PMC6201196 DOI: 10.3389/fphys.2018.01332] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 09/04/2018] [Indexed: 01/03/2023] Open
Abstract
Laminopathies are a clinically heterogeneous group of disorders caused by mutations in LMNA. The main proteins encoded by LMNA are Lamin A and C, which together with Lamin B1 and B2, form the nuclear lamina: a mesh-like structure located underneath the inner nuclear membrane. Laminopathies show striking tissue specificity, with subtypes affecting striated muscle, peripheral nerve, and adipose tissue, while others cause multisystem disease with accelerated aging. Although several pathogenic mechanisms have been proposed, the exact pathophysiology of laminopathies remains unclear, compounded by the rarity of these disorders and lack of easily accessible cell types to study. To overcome this limitation, we used induced pluripotent stem cells (iPSCs) from patients with skeletal muscle laminopathies such as LMNA-related congenital muscular dystrophy and limb-girdle muscular dystrophy 1B, to model disease phenotypes in vitro. iPSCs can be derived from readily accessible cell types, have unlimited proliferation potential and can be differentiated into cell types that would otherwise be difficult and invasive to obtain. iPSC lines from three skeletal muscle laminopathy patients were differentiated into inducible myogenic cells and myotubes. Disease-associated phenotypes were observed in these cells, including abnormal nuclear shape and mislocalization of nuclear lamina proteins. Nuclear abnormalities were less pronounced in monolayer cultures of terminally differentiated skeletal myotubes than in proliferating myogenic cells. Notably, skeletal myogenic differentiation of LMNA-mutant iPSCs in artificial muscle constructs improved detection of myonuclear abnormalities compared to conventional monolayer cultures across multiple pathogenic genotypes, providing a high-fidelity modeling platform for skeletal muscle laminopathies. Our results lay the foundation for future iPSC-based therapy development and screening platforms for skeletal muscle laminopathies.
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Affiliation(s)
- Heather B Steele-Stallard
- Department of Cell and Developmental Biology, University College London, London, United Kingdom.,Randall Centre for Cell and Molecular Biophysics, King's College London, London, United Kingdom
| | - Luca Pinton
- Department of Cell and Developmental Biology, University College London, London, United Kingdom.,Randall Centre for Cell and Molecular Biophysics, King's College London, London, United Kingdom
| | - Shilpita Sarcar
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Tanel Ozdemir
- Department of Cell and Developmental Biology, University College London, London, United Kingdom.,Randall Centre for Cell and Molecular Biophysics, King's College London, London, United Kingdom
| | - Sara M Maffioletti
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Peter S Zammit
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, United Kingdom
| | - Francesco Saverio Tedesco
- Department of Cell and Developmental Biology, University College London, London, United Kingdom.,The Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
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9
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Azibani F, Brull A, Arandel L, Beuvin M, Nelson I, Jollet A, Ziat E, Prudhon B, Benkhelifa-Ziyyat S, Bitoun M, Lorain S, Bonne G, Bertrand AT. Gene Therapy via Trans-Splicing for LMNA-Related Congenital Muscular Dystrophy. MOLECULAR THERAPY. NUCLEIC ACIDS 2017; 10:376-386. [PMID: 29499949 PMCID: PMC5862133 DOI: 10.1016/j.omtn.2017.12.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Revised: 12/20/2017] [Accepted: 12/20/2017] [Indexed: 11/28/2022]
Abstract
We assessed the potential of Lmna-mRNA repair by spliceosome-mediated RNA trans-splicing as a therapeutic approach for LMNA-related congenital muscular dystrophy. This gene therapy strategy leads to reduction of mutated transcript expression for the benefit of corresponding wild-type (WT) transcripts. We developed 5′-RNA pre-trans-splicing molecules containing the first five exons of Lmna and targeting intron 5 of Lmna pre-mRNA. Among nine pre-trans-splicing molecules, differing in the targeted sequence in intron 5 and tested in C2C12 myoblasts, three induced trans-splicing events on endogenous Lmna mRNA and confirmed at protein level. Further analyses performed in primary myotubes derived from an LMNA-related congenital muscular dystrophy (L-CMD) mouse model led to a partial rescue of the mutant phenotype. Finally, we tested this approach in vivo using adeno-associated virus (AAV) delivery in newborn mice and showed that trans-splicing events occurred in WT mice 50 days after AAV delivery, although at a low rate. Altogether, while these results provide the first evidence for reprogramming LMNA mRNA in vitro, strategies to improve the rate of trans-splicing events still need to be developed for efficient application of this therapeutic approach in vivo.
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Affiliation(s)
- Feriel Azibani
- Sorbonne Université, INSERM UMRS_974, Center of Research in Myology, 75013 Paris, France
| | - Astrid Brull
- Sorbonne Université, INSERM UMRS_974, Center of Research in Myology, 75013 Paris, France
| | - Ludovic Arandel
- Sorbonne Université, INSERM UMRS_974, Center of Research in Myology, 75013 Paris, France
| | - Maud Beuvin
- Sorbonne Université, INSERM UMRS_974, Center of Research in Myology, 75013 Paris, France
| | - Isabelle Nelson
- Sorbonne Université, INSERM UMRS_974, Center of Research in Myology, 75013 Paris, France
| | - Arnaud Jollet
- Sorbonne Université, INSERM UMRS_974, Center of Research in Myology, 75013 Paris, France
| | - Esma Ziat
- Sorbonne Université, INSERM UMRS_974, Center of Research in Myology, 75013 Paris, France
| | - Bernard Prudhon
- Sorbonne Université, INSERM UMRS_974, Center of Research in Myology, 75013 Paris, France
| | | | - Marc Bitoun
- Sorbonne Université, INSERM UMRS_974, Center of Research in Myology, 75013 Paris, France
| | - Stéphanie Lorain
- Sorbonne Université, INSERM UMRS_974, Center of Research in Myology, 75013 Paris, France
| | - Gisèle Bonne
- Sorbonne Université, INSERM UMRS_974, Center of Research in Myology, 75013 Paris, France
| | - Anne T Bertrand
- Sorbonne Université, INSERM UMRS_974, Center of Research in Myology, 75013 Paris, France.
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10
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A Novel Lamin A Mutant Responsible for Congenital Muscular Dystrophy Causes Distinct Abnormalities of the Cell Nucleus. PLoS One 2017; 12:e0169189. [PMID: 28125586 PMCID: PMC5268432 DOI: 10.1371/journal.pone.0169189] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 12/13/2016] [Indexed: 11/26/2022] Open
Abstract
A-type lamins, the intermediate filament proteins participating in nuclear structure and function, are encoded by LMNA. LMNA mutations can lead to laminopathies such as lipodystrophies, premature aging syndromes (progeria) and muscular dystrophies. Here, we identified a novel heterozygous LMNA p.R388P de novo mutation in a patient with a non-previously described severe phenotype comprising congenital muscular dystrophy (L-CMD) and lipodystrophy. In culture, the patient’s skin fibroblasts entered prematurely into senescence, and some nuclei showed a lamina honeycomb pattern. C2C12 myoblasts were transfected with a construct carrying the patient’s mutation; R388P-lamin A (LA) predominantly accumulated within the nucleoplasm and was depleted at the nuclear periphery, altering the anchorage of the inner nuclear membrane protein emerin and the nucleoplasmic protein LAP2-alpha. The mutant LA triggered a frequent and severe nuclear dysmorphy that occurred independently of prelamin A processing, as well as increased histone H3K9 acetylation. Nuclear dysmorphy was not significantly improved when transfected cells were treated with drugs disrupting microtubules or actin filaments or modifying the global histone acetylation pattern. Therefore, releasing any force exerted at the nuclear envelope by the cytoskeleton or chromatin did not rescue nuclear shape, in contrast to what was previously shown in Hutchinson-Gilford progeria due to other LMNA mutations. Our results point to the specific cytotoxic effect of the R388P-lamin A mutant, which is clinically related to a rare and severe multisystemic laminopathy phenotype.
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The effect of the lamin A and its mutants on nuclear structure, cell proliferation, protein stability, and mobility in embryonic cells. Chromosoma 2016; 126:501-517. [PMID: 27534416 PMCID: PMC5509783 DOI: 10.1007/s00412-016-0610-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2016] [Revised: 07/11/2016] [Accepted: 08/02/2016] [Indexed: 01/26/2023]
Abstract
LMNA gene encodes for nuclear intermediate filament proteins lamin A/C. Mutations in this gene lead to a spectrum of genetic disorders, collectively referred to as laminopathies. Lamin A/C are widely expressed in most differentiated somatic cells but not in early embryos and some undifferentiated cells. To investigate the role of lamin A/C in cell phenotype maintenance and differentiation, which could be a determinant of the pathogenesis of laminopathies, we examined the role played by exogenous lamin A and its mutants in differentiated cell lines (HeLa, NHDF) and less-differentiated HEK 293 cells. We introduced exogenous wild-type and mutated (H222P, L263P, E358K D446V, and ∆50) lamin A into different cell types and analyzed proteins’ impact on proliferation, protein mobility, and endogenous nuclear envelope protein distribution. The mutants give rise to a broad spectrum of nuclear phenotypes and relocate lamin C. The mutations ∆50 and D446V enhance proliferation in comparison to wild-type lamin A and control cells, but no changes in exogenous protein mobility measured by FRAP were observed. Interestingly, although transcripts for lamins A and C are at similar level in HEK 293 cells, only lamin C protein is detected in western blots. Also, exogenous lamin A and its mutants, when expressed in HEK 293 cells underwent posttranscriptional processing. Overall, our results provide new insight into the maintenance of lamin A in less-differentiated cells. Embryonic cells are very sensitive to lamin A imbalance, and its upregulation disturbs lamin C, which may influence gene expression and many regulatory pathways.
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Lamm CE, Link K, Wagner S, Milbradt J, Marschall M, Sonnewald U. Human Cytomegalovirus Nuclear Egress Proteins Ectopically Expressed in the Heterologous Environment of Plant Cells are Strictly Targeted to the Nuclear Envelope. Viruses 2016; 8:73. [PMID: 26978388 PMCID: PMC4810263 DOI: 10.3390/v8030073] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 02/23/2016] [Accepted: 02/29/2016] [Indexed: 12/14/2022] Open
Abstract
In all eukaryotic cells, the nucleus forms a prominent cellular compartment containing the cell's nuclear genome. Although structurally similar, animal and plant nuclei differ substantially in details of their architecture. One example is the nuclear lamina, a layer of tightly interconnected filament proteins (lamins) underlying the nuclear envelope of metazoans. So far no orthologous lamin genes could be detected in plant genomes and putative lamin-like proteins are only poorly described in plants. To probe for potentially conserved features of metazoan and plant nuclear envelopes, we ectopically expressed the core nuclear egress proteins of human cytomegalovirus pUL50 and pUL53 in plant cells. pUL50 localizes to the inner envelope of metazoan nuclei and recruits the nuclear localized pUL53 to it, forming heterodimers. Upon expression in plant cells, a very similar localization pattern of both proteins could be determined. Notably, pUL50 is specifically targeted to the plant nuclear envelope in a rim-like fashion, a location to which coexpressed pUL53 becomes strictly corecruited from its initial nucleoplasmic distribution. Using pUL50 as bait in a yeast two-hybrid screening, the cytoplasmic re-initiation supporting protein RISP could be identified. Interaction of pUL50 and RISP could be confirmed by coexpression and coimmunoprecipitation in mammalian cells and by confocal laser scanning microscopy in plant cells, demonstrating partial pUL50-RISP colocalization in areas of the nuclear rim and other intracellular compartments. Thus, our study provides strong evidence for conserved structural features of plant and metazoan nuclear envelops and identifies RISP as a potential pUL50-interacting plant protein.
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Affiliation(s)
- Christian E Lamm
- Division of Biochemistry, Department of Biology, Friedrich-Alexander University Erlangen-Nuremberg, Staudtstrasse 5, Erlangen 91058, Germany.
| | - Katrin Link
- Division of Biochemistry, Department of Biology, Friedrich-Alexander University Erlangen-Nuremberg, Staudtstrasse 5, Erlangen 91058, Germany.
| | - Sabrina Wagner
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University Erlangen-Nuremberg, Schloßgarten 4, Erlangen 91054, Germany.
| | - Jens Milbradt
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University Erlangen-Nuremberg, Schloßgarten 4, Erlangen 91054, Germany.
| | - Manfred Marschall
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University Erlangen-Nuremberg, Schloßgarten 4, Erlangen 91054, Germany.
| | - Uwe Sonnewald
- Division of Biochemistry, Department of Biology, Friedrich-Alexander University Erlangen-Nuremberg, Staudtstrasse 5, Erlangen 91058, Germany.
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Yang M, Yuan ZM. A novel role of PRR14 in the regulation of skeletal myogenesis. Cell Death Dis 2015; 6:e1734. [PMID: 25906157 PMCID: PMC4650536 DOI: 10.1038/cddis.2015.103] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 03/11/2015] [Accepted: 03/13/2015] [Indexed: 12/11/2022]
Abstract
Dysregulation of genes involved in organizing and maintaining nuclear structures, such as SYNE1, SYNE2, TREM43, EMD and LMNA is frequently associated with diverse diseases termed laminopathies, which often affect the muscle tissue. The PRR14 protein was recently reported to tether heterochromatin to nuclear lamina but its function remains largely unknown. Here, we present several lines of evidence demonstrating a critical role of PRR14 in regulation of myoblast differentiation. We found that Prr14 expression was upregulated during skeletal myogenesis. Knockdown of Prr14 impeded, whereas overexpression of PRR14 enhanced C2C12 differentiation. The pro-myogenesis activity of PRR14 seemed to correlate with its ability to support cell survival and to maintain the stability and structure of lamin A/C. In addition, PRR14 stimulated the activity of MyoD via binding to heterochromatin protein 1 alpha (HP1α). The results altogether support a model in which PRR14 promotes skeletal myogenesis via supporting nuclear lamina structure and enhancing the activity of MyoD.
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Affiliation(s)
- M Yang
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Z-M Yuan
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, USA
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Coyaud E, Mis M, Laurent EMN, Dunham WH, Couzens AL, Robitaille M, Gingras AC, Angers S, Raught B. BioID-based Identification of Skp Cullin F-box (SCF)β-TrCP1/2 E3 Ligase Substrates. Mol Cell Proteomics 2015; 14:1781-95. [PMID: 25900982 DOI: 10.1074/mcp.m114.045658] [Citation(s) in RCA: 124] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Indexed: 11/06/2022] Open
Abstract
The identification of ubiquitin E3 ligase substrates has been challenging, due in part to low-affinity, transient interactions, the rapid degradation of targets and the inability to identify proteins from poorly soluble cellular compartments. SCF(β-TrCP1) and SCF(β-TrCP2) are well-studied ubiquitin E3 ligases that target substrates for proteasomal degradation, and play important roles in Wnt, Hippo, and NFκB signaling. Combining 26S proteasome inhibitor (MG132) treatment with proximity-dependent biotin labeling (BioID) and semiquantitative mass spectrometry, here we identify SCF(β-TrCP1/2) interacting partners. Based on their enrichment in the presence of MG132, our data identify over 50 new putative SCF(β-TrCP1/2) substrates. We validate 12 of these new substrates and reveal previously unsuspected roles for β-TrCP in the maintenance of nuclear membrane integrity, processing (P)-body turnover and translational control. Together, our data suggest that β-TrCP is an important hub in the cellular stress response. The technique presented here represents a complementary approach to more standard IP-MS methods and should be broadly applicable for the identification of substrates for many ubiquitin E3 ligases.
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Affiliation(s)
- Etienne Coyaud
- From the ‡Princess Margaret Cancer Centre, University Health Network
| | - Monika Mis
- §Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto
| | | | - Wade H Dunham
- ¶Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital
| | - Amber L Couzens
- ¶Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital
| | - Melanie Robitaille
- §Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto
| | - Anne-Claude Gingras
- ¶Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital; ‖Department of Molecular Genetics, University of Toronto
| | - Stephane Angers
- §Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto; **Department of Biochemistry, University of Toronto
| | - Brian Raught
- From the ‡Princess Margaret Cancer Centre, University Health Network; ‡‡Department of Medical Biophysics, University of Toronto, Toronto, ON Canada
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Vadrot N, Duband-Goulet I, Cabet E, Attanda W, Barateau A, Vicart P, Gerbal F, Briand N, Vigouroux C, Oldenburg AR, Lund EG, Collas P, Buendia B. The p.R482W substitution in A-type lamins deregulates SREBP1 activity in Dunnigan-type familial partial lipodystrophy. Hum Mol Genet 2014; 24:2096-109. [PMID: 25524705 DOI: 10.1093/hmg/ddu728] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Nuclear lamins are involved in many cellular functions due to their ability to bind numerous partners including chromatin and transcription factors, and affect their properties. Dunnigan type familial partial lipodystrophy (FPLD2; OMIM#151660) is caused in most cases by the A-type lamin R482W mutation. We report here that the R482W mutation affects the regulatory activity of sterol response element binding protein 1 (SREBP1), a transcription factor that regulates hundreds of genes involved in lipid metabolism and adipocyte differentiation. Using in situ proximity ligation assays (PLA), reporter assays and biochemical and transcriptomic approaches, we show that interactions of SREBP1 with lamin A and lamin C occur at the nuclear periphery and in the nucleoplasm. These interactions involve the Ig-fold of A-type lamins and are favored upon SREBP1 binding to its DNA target sequences. We show that SREBP1, LMNA and sterol response DNA elements form ternary complexes in vitro. In addition, overexpression of A-type lamins reduces transcriptional activity of SREBP1. In contrast, both overexpression of LMNA R482W in primary human preadipocytes and endogenous expression of A-type lamins R482W in FPLD2 patient fibroblasts, reduce A-type lamins-SREBP1 in situ interactions and upregulate a large number of SREBP1 target genes. As this LMNA mutant was previously shown to inhibit adipogenic differentiation, we propose that deregulation of SREBP1 by mutated A-type lamins constitutes one underlying mechanism of the physiopathology of FPLD2. Our data suggest that SREBP1 targeting molecules could be considered in a therapeutic context.
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Affiliation(s)
- Nathalie Vadrot
- Unit of Functional and Adaptive Biology (BFA), Université Paris Diderot-Paris 7 Affiliated with CNRS, 4 rue Marie-Andrée Lagroua Weill-Halle, Paris Cedex 13 75205, France
| | - Isabelle Duband-Goulet
- Unit of Functional and Adaptive Biology (BFA), Université Paris Diderot-Paris 7 Affiliated with CNRS, 4 rue Marie-Andrée Lagroua Weill-Halle, Paris Cedex 13 75205, France
| | - Eva Cabet
- Unit of Functional and Adaptive Biology (BFA), Université Paris Diderot-Paris 7 Affiliated with CNRS, 4 rue Marie-Andrée Lagroua Weill-Halle, Paris Cedex 13 75205, France
| | - Wikayatou Attanda
- Unit of Functional and Adaptive Biology (BFA), Université Paris Diderot-Paris 7 Affiliated with CNRS, 4 rue Marie-Andrée Lagroua Weill-Halle, Paris Cedex 13 75205, France
| | - Alice Barateau
- Unit of Functional and Adaptive Biology (BFA), Université Paris Diderot-Paris 7 Affiliated with CNRS, 4 rue Marie-Andrée Lagroua Weill-Halle, Paris Cedex 13 75205, France
| | - Patrick Vicart
- Unit of Functional and Adaptive Biology (BFA), Université Paris Diderot-Paris 7 Affiliated with CNRS, 4 rue Marie-Andrée Lagroua Weill-Halle, Paris Cedex 13 75205, France
| | - Fabien Gerbal
- Université Paris Diderot, Matière et Systèmes Complexes, CNRS UMR 7057, 10 rue Alice Domon et Leonie Duquet, Paris Cedex 13 75205, France, Physics Department, Université Pierre et Marie Curie, Paris UFR925, France
| | - Nolwenn Briand
- Faculté de Médecine Pierre et Marie Curie, Inserm, UMR S938, Centre de Recherche Saint-Antoine, 27 rue Chaligny, Paris F-75012, France, Sorbonne Universités, UPMC Univ Paris 6, UMR S938, Paris F-75005, France, ICAN, Institute of Cardiometabolism and Nutrition, Paris F-75013, France
| | - Corinne Vigouroux
- Faculté de Médecine Pierre et Marie Curie, Inserm, UMR S938, Centre de Recherche Saint-Antoine, 27 rue Chaligny, Paris F-75012, France, Sorbonne Universités, UPMC Univ Paris 6, UMR S938, Paris F-75005, France, ICAN, Institute of Cardiometabolism and Nutrition, Paris F-75013, France, Laboratoire Commun de Biologie et Génétique Moléculaires, AP-HP, Hôpital Saint-Antoine, Paris F-75012, France and
| | - Anja R Oldenburg
- Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, PO Box 1112 Blindern, Oslo 0317, Norway
| | - Eivind G Lund
- Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, PO Box 1112 Blindern, Oslo 0317, Norway
| | - Philippe Collas
- Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, PO Box 1112 Blindern, Oslo 0317, Norway
| | - Brigitte Buendia
- Unit of Functional and Adaptive Biology (BFA), Université Paris Diderot-Paris 7 Affiliated with CNRS, 4 rue Marie-Andrée Lagroua Weill-Halle, Paris Cedex 13 75205, France,
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Abstract
Much of the work on nuclear lamins during the past 15 years has focused on mutations in LMNA (the gene for prelamin A and lamin C) that cause particular muscular dystrophy, cardiomyopathy, partial lipodystrophy, and progeroid syndromes. These disorders, often called "laminopathies," mainly affect mesenchymal tissues (e.g., striated muscle, bone, and fibrous tissue). Recently, however, a series of papers have identified important roles for nuclear lamins in the central nervous system. Studies of knockout mice uncovered a key role for B-type lamins (lamins B1 and B2) in neuronal migration in the developing brain. Also, duplications of LMNB1 (the gene for lamin B1) have been shown to cause autosome-dominant leukodystrophy. Finally, recent studies have uncovered a peculiar pattern of nuclear lamin expression in the brain. Lamin C transcripts are present at high levels in the brain, but prelamin A expression levels are very low-due to regulation of prelamin A transcripts by microRNA 9. This form of prelamin A regulation likely explains why "prelamin A diseases" such as Hutchinson-Gilford progeria syndrome spare the central nervous system. In this review, we summarize recent progress in elucidating links between nuclear lamins and neurobiology.
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Nuclear envelope-related lipodystrophies. Semin Cell Dev Biol 2014; 29:148-57. [DOI: 10.1016/j.semcdb.2013.12.015] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 12/06/2013] [Accepted: 12/20/2013] [Indexed: 12/12/2022]
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Gesson K, Vidak S, Foisner R. Lamina-associated polypeptide (LAP)2α and nucleoplasmic lamins in adult stem cell regulation and disease. Semin Cell Dev Biol 2013; 29:116-24. [PMID: 24374133 PMCID: PMC4053830 DOI: 10.1016/j.semcdb.2013.12.009] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 12/10/2013] [Accepted: 12/15/2013] [Indexed: 10/25/2022]
Abstract
A-type lamins are components of the lamina network at the nuclear envelope, which mediates nuclear stiffness and anchors chromatin to the nuclear periphery. However, A-type lamins are also found in the nuclear interior. Here we review the roles of the chromatin-associated, nucleoplasmic LEM protein, lamina-associated polypeptide 2α (LAP2α) in the regulation of A-type lamins in the nuclear interior. The lamin A/C-LAP2α complex may be involved in the regulation of the retinoblastoma protein-mediated pathway and other signaling pathways balancing proliferation and differentiation, and in the stabilization of higher-order chromatin organization throughout the nucleus. Loss of LAP2α in mice leads to selective depletion of the nucleoplasmic A-type lamin pool, promotes the proliferative stem cell phenotype of tissue progenitor cells, and delays stem cell differentiation. These findings support the hypothesis that LAP2α and nucleoplasmic lamins are regulators of adult stem cell function and tissue homeostasis. Finally, we discuss potential implications of this concept for defining the molecular disease mechanisms of lamin-linked diseases such as muscular dystrophy and premature aging syndromes.
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Affiliation(s)
- Kevin Gesson
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University Vienna, Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | - Sandra Vidak
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University Vienna, Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | - Roland Foisner
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University Vienna, Dr. Bohr-Gasse 9, 1030 Vienna, Austria.
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Saj M, Bilinska ZT, Tarnowska A, Sioma A, Bolongo P, Sobieszczanska-Malek M, Michalak E, Golen D, Mazurkiewicz L, Malek L, Walczak E, Fidzianska A, Grzybowski J, Przybylski A, Zielinski T, Korewicki J, Tesson F, Ploski R. LMNA mutations in Polish patients with dilated cardiomyopathy: prevalence, clinical characteristics, and in vitro studies. BMC MEDICAL GENETICS 2013; 14:55. [PMID: 23702046 PMCID: PMC3666888 DOI: 10.1186/1471-2350-14-55] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Accepted: 05/17/2013] [Indexed: 12/11/2022]
Abstract
Background LMNA mutations are most frequently involved in the pathogenesis of dilated cardiomyopathy with conduction disease. The goal of this study was to identify LMNA mutations, estimate their frequency among Polish dilated cardiomyopathy patients and characterize their effect both in vivo and in vitro. Methods Between January, 2008 and June, 2012 two patient populations were screened for the presence of LMNA mutations by direct sequencing: 66 dilated cardiomyopathy patients including 27 heart transplant recipients and 39 dilated cardiomyopathy patients with heart failure referred for heart transplantation evaluation, and 44 consecutive dilated cardiomyopathy patients, referred for a family evaluation and mutation screening. Results We detected nine non-synonymous mutations including three novel mutations: p.Ser431*, p.Val256Gly and p.Gly400Argfs*11 deletion. There were 25 carriers altogether in nine families. The carriers were mostly characterized by dilated cardiomyopathy and heart failure with conduction system disease and/or complex ventricular arrhythmia, although five were asymptomatic. Among the LMNA mutation carriers, six underwent heart transplantation, fourteen ICD implantation and eight had pacemaker. In addition, we obtained ultrastructural images of cardiomyocytes from the patient carrying p.Thr510Tyrfs*42. Furthermore, because the novel p.Val256Gly mutation was found in a sporadic case, we verified its pathogenicity by expressing the mutation in a cellular model. Conclusions In conclusion, in the two referral centre populations, the screening revealed five mutations among 66 heart transplant recipients or patients referred for heart transplantation (7.6%) and four mutations among 44 consecutive dilated cardiomyopathy patients referred for familial evaluation (9.1%). Dilated cardiomyopathy patients with LMNA mutations have poor prognosis, however considerable clinical variability is present among family members.
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Affiliation(s)
- Michal Saj
- Laboratory of Molecular Biology, Institute of Cardiology, Warsaw, Alpejska 42 04-628, Poland
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Cattin ME, Bertrand AT, Schlossarek S, Le Bihan MC, Skov Jensen S, Neuber C, Crocini C, Maron S, Lainé J, Mougenot N, Varnous S, Fromes Y, Hansen A, Eschenhagen T, Decostre V, Carrier L, Bonne G. Heterozygous LmnadelK32 mice develop dilated cardiomyopathy through a combined pathomechanism of haploinsufficiency and peptide toxicity. Hum Mol Genet 2013; 22:3152-64. [DOI: 10.1093/hmg/ddt172] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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21
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Martínez-Vieyra IA, Vásquez-Limeta A, González-Ramírez R, Morales-Lázaro SL, Mondragón M, Mondragón R, Ortega A, Winder SJ, Cisneros B. A role for β-dystroglycan in the organization and structure of the nucleus in myoblasts. BIOCHIMICA ET BIOPHYSICA ACTA 2013; 1833:698-711. [PMID: 23220011 DOI: 10.1016/j.bbamcr.2012.11.019] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Revised: 11/17/2012] [Accepted: 11/24/2012] [Indexed: 12/19/2022]
Abstract
We recently characterized a nuclear import pathway for β-dystroglycan; however, its nuclear role remains unknown. In this study, we demonstrate for the first time, the interaction of β-dystroglycan with distinct proteins from different nuclear compartments, including the nuclear envelope (NE) (emerin and lamins A/C and B1), splicing speckles (SC35), Cajal bodies (p80-coilin), and nucleoli (Nopp140). Electron microscopy analysis revealed that β-dystroglycan localized in the inner nuclear membrane, nucleoplasm, and nucleoli. Interestingly, downregulation of β-dystroglycan resulted in both mislocalization and decreased expression of emerin and lamin B1, but not lamin A/C, as well in disorganization of nucleoli, Cajal bodies, and splicing speckles with the concomitant decrease in the levels of Nopp140, and p80-coilin, but not SC35. Quantitative reverse transcription PCR and cycloheximide-mediated protein arrest assays revealed that β-dystroglycan deficiency did not change mRNA expression of NE proteins emerin and lamin B1 bud did alter their stability, accelerating protein turnover. Furthermore, knockdown of β-dystroglycan disrupted NE-mediated processes including nuclear morphology and centrosome-nucleus linkage, which provides evidence that β-dystroglycan association with NE proteins is biologically relevant. Unexpectedly, β-dystroglycan-depleted cells exhibited multiple centrosomes, a characteristic of cancerous cells. Overall, these findings imply that β-dystroglycan is a nuclear scaffolding protein involved in nuclear organization and NE structure and function, and that might be a contributor to the biogenesis of nuclear envelopathies.
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Affiliation(s)
- Ivette A Martínez-Vieyra
- Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del IPN, México, DF 07360, Mexico
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22
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Abstract
The LINC (linker of nucleoskeleton and cytoskeleton) complex is a proposed mechanical link tethering the nucleo- and cyto-skeleton via the NE (nuclear envelope). The LINC components emerin, lamin A/C, SUN1, SUN2, nesprin-1 and nesprin-2 interact with each other at the NE and also with other binding partners including actin filaments and B-type lamins. Besides the mechanostructural functions, the LINC complex is also involved in signalling pathways and gene regulation. Emerin was the first LINC component associated with a human disease, namely EDMD (Emery-Dreifuss muscular dystrophy). Later on, other components of the LINC complex, such as lamins A/C and small isoforms of nesprin-1 and nesprin-2, were found to be associated with EDMD, reflecting a genetic heterogeneity that has not been resolved so far. Only approximately 46% of the EDMD patients can be linked to genes of LINC and non-LINC components, pointing to further genes involved in the pathology of EDMD. Obvious candidates are the LINC proteins SUN1 and SUN2. Recently, screening of binding partners of LINC components as candidates identified LUMA (TMEM43), encoding a binding partner of emerin and lamins, as a gene involved in atypical EDMD. Nevertheless, such mutations contribute only to a very small fraction of EDMD patients. EDMD-causing mutations in STA/EMD (encoding emerin) that disrupt emerin binding to Btf (Bcl-2-associated transcription factor), GCL (germ cell-less) and BAF (barrier to autointegration factor) provide the first glimpses into LINC being involved in gene regulation and thus opening new avenues for functional studies. Thus the association of LINC with human disease provides tools for understanding its functions within the cell.
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Magagnotti C, Bachi A, Zerbini G, Fattore E, Fermo I, Riba M, Previtali SC, Ferrari M, Andolfo A, Benedetti S. Protein profiling reveals energy metabolism and cytoskeletal protein alterations in LMNA mutation carriers. Biochim Biophys Acta Mol Basis Dis 2012; 1822:970-9. [PMID: 22326558 DOI: 10.1016/j.bbadis.2012.01.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Revised: 12/21/2011] [Accepted: 01/27/2012] [Indexed: 12/11/2022]
Abstract
Nuclear envelope-related muscular dystrophies, in particular those referred to as laminopathies, are relatively novel and unclear diseases, also considering the increasing number of mutations identified so far in genes of the nuclear envelope. As regard LMNA gene, only tentative relations between phenotype, type and localization of the mutations have been established in striated muscle diseases, while laminopathies affecting adipose tissue, peripheral nerves or progerioid syndromes could be linked to specific genetic variants. This study describes the biochemical phenotype of neuromuscular laminopathies in samples derived from LMNA mutant patients. Since it has been reported that nuclear alterations, due to LMNA defects, are present also in fibroblasts from Emery-Dreifuss muscular dystrophy and familial partial lipodystrophy patients, we analyzed 2D-maps of skin fibroblasts of patients carrying 12 different LMNA mutations spread along the entire gene. To recognize distinctive proteins underlying affected biochemical pathways, we compared them with fibroblasts from healthy controls and, more importantly, fibroblasts from patients with non-lamin related neuromuscular disorders. We found less abundance of cytoskeletal/structural proteins, confirming a dominant role for Lamin A/C in structural support of nuclear architecture. Interestingly, we also established significant changes in the expression of proteins involved in cellular energy production and oxidative stress response. To our knowledge, this is the first report where proteomics was applied to characterize ex-vivo cells from LMNA patients, suggesting that this may represent a new approach to better understand the molecular mechanisms of these rare diseases and facilitate the development of novel therapeutic treatments.
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Affiliation(s)
- Cinzia Magagnotti
- ProMiFa, Protein Microsequencing Facility, Division of Cell Biology and Genetics, San Raffaele Scientific Institute, Milan, Italy
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Duband-Goulet I, Woerner S, Gasparini S, Attanda W, Kondé E, Tellier-Lebègue C, Craescu CT, Gombault A, Roussel P, Vadrot N, Vicart P, Ostlund C, Worman HJ, Zinn-Justin S, Buendia B. Subcellular localization of SREBP1 depends on its interaction with the C-terminal region of wild-type and disease related A-type lamins. Exp Cell Res 2011; 317:2800-13. [PMID: 21993218 DOI: 10.1016/j.yexcr.2011.09.012] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Revised: 09/02/2011] [Accepted: 09/26/2011] [Indexed: 11/26/2022]
Abstract
Lamins A and C are nuclear intermediate filament proteins expressed in most differentiated somatic cells. Previous data suggested that prelamin A, the lamin A precursor, accumulates in some lipodystrophy syndromes caused by mutations in the lamin A/C gene, and binds and inactivates the sterol regulatory element binding protein 1 (SREBP1). Here we show that, in vitro, the tail regions of prelamin A, lamin A and lamin C bind a polypeptide of SREBP1. Such interactions also occur in HeLa cells, since expression of lamin tail regions impedes nucleolar accumulation of the SREBP1 polypeptide fused to a nucleolar localization signal sequence. In addition, the tail regions of A-type lamin variants that occur in Dunnigan-type familial partial lipodystrophy of (R482W) and Hutchison Gilford progeria syndrome (∆607-656) bind to the SREBP1 polypeptide in vitro, and the corresponding FLAG-tagged full-length lamin variants co-immunoprecipitate the SREBP1 polypeptide in cells. Overexpression of wild-type A-type lamins and variants favors SREBP1 polypeptide localization at the intranuclear periphery, suggesting its sequestration. Our data support the hypothesis that variation of A-type lamin protein level and spatial organization, in particular due to disease-linked mutations, influences the sequestration of SREBP1 at the nuclear envelope and thus contributes to the regulation of SREBP1 function.
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Affiliation(s)
- Isabelle Duband-Goulet
- Laboratoire du Stress et Pathologies du Cytosquelette, Université Paris Diderot-Paris 7, CNRS, Institut de Biologie Fonctionnelle et Adaptative, 4 rue M.A. Lagroua Weill Halle, 75205 Paris cedex 13, France
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25
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Lamins, laminopathies and disease mechanisms: Possible role for proteasomal degradation of key regulatory proteins. J Biosci 2011; 36:471-9. [DOI: 10.1007/s12038-011-9085-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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26
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Kheterpal I, Ku G, Coleman L, Yu G, Ptitsyn AA, Floyd ZE, Gimble JM. Proteome of human subcutaneous adipose tissue stromal vascular fraction cells versus mature adipocytes based on DIGE. J Proteome Res 2011; 10:1519-27. [PMID: 21261302 PMCID: PMC3070065 DOI: 10.1021/pr100887r] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Adipose tissue contains a heterogeneous population of mature adipocytes, endothelial cells, immune cells, pericytes, and preadipocytic stromal/stem cells. To date, a majority of proteomic analyses have focused on intact adipose tissue or isolated adipose stromal/stem cells in vitro. In this study, human subcutaneous adipose tissue from multiple depots (arm and abdomen) obtained from female donors was separated into populations of stromal vascular fraction cells and mature adipocytes. Out of 960 features detected by 2-D gel electrophoresis, a total of 200 features displayed a 2-fold up- or down-regulation relative to each cell population. The protein identity of 136 features was determined. Immunoblot analyses comparing SVF relative to adipocytes confirmed that carbonic anhydrase II was up-regulated in both adipose depots while catalase was up-regulated in the arm only. Bioinformatic analyses of the data set determined that cytoskeletal, glycogenic, glycolytic, lipid metabolic, and oxidative stress related pathways were highly represented as differentially regulated between the mature adipocytes and stromal vascular fraction cells. These findings extend previous reports in the literature with respect to the adipose tissue proteome and the consequences of adipogenesis. The proteins identified may have value as biomarkers for monitoring the physiology and pathology of cell populations within subcutaneous adipose depots.
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Affiliation(s)
- Indu Kheterpal
- Proteomics and Metabolomics Core Facility, Louisiana State University System, 6400 Perkins Road, Baton Rouge, LA 70808
- Protein Structural Biology, Louisiana State University System, 6400 Perkins Road, Baton Rouge, LA 70808
| | - Ginger Ku
- Proteomics and Metabolomics Core Facility, Louisiana State University System, 6400 Perkins Road, Baton Rouge, LA 70808
- Protein Structural Biology, Louisiana State University System, 6400 Perkins Road, Baton Rouge, LA 70808
| | - Liana Coleman
- Proteomics and Metabolomics Core Facility, Louisiana State University System, 6400 Perkins Road, Baton Rouge, LA 70808
| | - Gang Yu
- Stem Cell Biology Laboratory, Louisiana State University System, 6400 Perkins Road, Baton Rouge, LA 70808
| | - Andrey A. Ptitsyn
- Center for Bioinformatics, College of Veterinary Medicine and Biomedical Sciences Department of Microbiology Immunology & Pathology, Colorado State University, Fort Collins, CO 80523-1682
| | - Z. Elizabeth Floyd
- Ubiquitin Laboratory, Pennington Biomedical Research Center, Louisiana State University System, 6400 Perkins Road, Baton Rouge, LA 70808
| | - Jeffrey M. Gimble
- Stem Cell Biology Laboratory, Louisiana State University System, 6400 Perkins Road, Baton Rouge, LA 70808
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Abstract
Emery-Dreifuss muscular dystrophy (EDMD) is a progressive muscle-wasting disorder defined by early contractures of the Achilles tendon, spine, and elbows. EDMD is also distinctive for its association with defects of the cardiac conduction system that can result in sudden death. It can be inherited in an X-linked, autosomal dominant, or autosomal recessive fashion and is caused by mutations in proteins of the nuclear membrane. Mutations in the EMD gene, which encodes emerin, a transmembrane protein found at the inner nuclear membrane, are responsible for X-linked EDMD. The most common etiology of autosomal dominant EDMD is an LMNA gene mutation; LMNA encodes the intermediate filament protein lamins A and C, which constitute the major scaffolding protein of the inner nuclear membrane. Murine models of LMNA gene mutations have helped to identify different mechanisms of disease. Loss of LMNA function leads to nuclear fragility as well as other defects, such as abnormal nuclear function. Additional genes encoding nuclear membrane proteins such as SYNE1 and SYNE2 have also been implicated in EDMD, and in some cases their importance for cardiac and muscle function has been supported by animal modeling.
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28
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Abstract
The nuclear lamins are type V intermediate filament proteins that are critically important for the structural properties of the nucleus. In addition, they are involved in the regulation of numerous nuclear processes, including DNA replication, transcription and chromatin organization. The developmentally regulated expression of lamins suggests that they are involved in cellular differentiation. Their assembly dynamic properties throughout the cell cycle, particularly in mitosis, are influenced by posttranslational modifications. Lamins may regulate nuclear functions by direct interactions with chromatin and determining the spatial organization of chromosomes within the nuclear space. They may also regulate chromatin functions by interacting with factors that epigenetically modify the chromatin or directly regulate replication or transcription.
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Affiliation(s)
- Thomas Dechat
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
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29
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Chaturvedi P, Parnaik VK. Lamin A rod domain mutants target heterochromatin protein 1alpha and beta for proteasomal degradation by activation of F-box protein, FBXW10. PLoS One 2010; 5:e10620. [PMID: 20498703 PMCID: PMC2869352 DOI: 10.1371/journal.pone.0010620] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2010] [Accepted: 04/20/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Lamins are major structural proteins of the nucleus and contribute to the organization of various nuclear functions. Mutations in the human lamin A gene cause a number of highly degenerative diseases, collectively termed as laminopathies. Cells expressing lamin mutations exhibit abnormal nuclear morphology and altered heterochromatin organization; however, the mechanisms responsible for these defects are not well understood. METHODOLOGY AND PRINCIPAL FINDINGS The lamin A rod domain mutants G232E, Q294P and R386K are either diffusely distributed or form large aggregates in the nucleoplasm, resulting in aberrant nuclear morphology in various cell types. We examined the effects of these lamin mutants on the distribution of heterochromatin protein 1 (HP1) isoforms. HeLa cells expressing these mutants showed a heterogeneous pattern of HP1alpha and beta depletion but without altering HP1gamma levels. Changes in HP1alpha and beta were not observed in cells expressing wild-type lamin A or mutant R482L, which assembled normally at the nuclear rim. Treatment with proteasomal inhibitors led to restoration of levels of HP1 isoforms and also resulted in stable association of lamin mutants with the nuclear periphery, rim localization of the inner nuclear membrane lamin-binding protein emerin and partial improvement of nuclear morphology. A comparison of the stability of HP1 isoforms indicated that HP1alpha and beta displayed increased turnover and higher basal levels of ubiquitination than HP1gamma. Transcript analysis of components of the ubiquitination pathway showed that a specific F-box protein, FBXW10 was induced several-fold in cells expressing lamin mutants. Importantly, ectopic expression of FBXW10 in HeLa cells led to depletion of HP1alpha and beta without alteration of HP1gamma levels. CONCLUSIONS Mislocalized lamins can induce ubiquitin-mediated proteasomal degradation of certain HP1 isoforms by activation of FBXW10, a member of the F-box family of proteins that is involved in E3 ubiquitin ligase activity.
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Affiliation(s)
| | - Veena K. Parnaik
- Centre for Cellular and Molecular Biology (CSIR), Hyderabad, India
- * E-mail:
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30
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Fischer AH, Zhao C, Li QK, Gustafson KS, Eltoum IE, Tambouret R, Benstein B, Savaloja LC, Kulesza P. The cytologic criteria of malignancy. J Cell Biochem 2010; 110:795-811. [DOI: 10.1002/jcb.22585] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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31
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Gurudatta BV, Shashidhara LS, Parnaik VK. Lamin C and chromatin organization in Drosophila. J Genet 2010; 89:37-49. [DOI: 10.1007/s12041-010-0009-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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32
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Gupta P, Bilinska ZT, Sylvius N, Boudreau E, Veinot JP, Labib S, Bolongo PM, Hamza A, Jackson T, Ploski R, Walski M, Grzybowski J, Walczak E, Religa G, Fidzianska A, Tesson F. Genetic and ultrastructural studies in dilated cardiomyopathy patients: a large deletion in the lamin A/C gene is associated with cardiomyocyte nuclear envelope disruption. Basic Res Cardiol 2010; 105:365-77. [PMID: 20127487 DOI: 10.1007/s00395-010-0085-4] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2009] [Revised: 01/12/2010] [Accepted: 01/13/2010] [Indexed: 12/24/2022]
Abstract
Major nuclear envelope abnormalities, such as disruption and/or presence of intranuclear organelles, have rarely been described in cardiomyocytes from dilated cardiomyopathy (DCM) patients. In this study, we screened a series of 25 unrelated DCM patient samples for (a) cardiomyocyte nuclear abnormalities and (b) mutations in LMNA and TMPO as they are two DCM-causing genes that encode proteins involved in maintaining nuclear envelope architecture. Among the 25 heart samples investigated, we identified major cardiomyocyte nuclear abnormalities in 8 patients. Direct sequencing allowed the detection of three heterozygous LMNA mutations (p.D192G, p.Q353K and p.R541S) in three patients. By multiplex ligation-dependant probe amplification (MLPA)/quantitative real-time PCR, we found a heterozygous deletion encompassing exons 3-12 of the LMNA gene in one patient. Immunostaining demonstrated that this deletion led to a decrease in lamin A/C expression in cardiomyocytes from this patient. This LMNA deletion as well as the p.D192G mutation was found in patients displaying major cardiomyocyte nuclear envelope abnormalities, while the p.Q353K and p.R541S mutations were found in patients without specific nuclear envelope abnormalities. None of the DCM patients included in the study carried a mutation in the TMPO gene. Taken together, we found no evidence of a genotype-phenotype relationship between the onset and the severity of DCM, the presence of nuclear abnormalities and the presence or absence of LMNA mutations. We demonstrated that a large deletion in LMNA associated with reduced levels of the protein in the nuclear envelope suggesting a haploinsufficiency mechanism can lead to cardiomyocyte nuclear envelope disruption and thus underlie the pathogenesis of DCM.
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Affiliation(s)
- Pallavi Gupta
- Faculty of Health Sciences, University of Ottawa, Ottawa, ON, K1H 8M5, Canada
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Padiath QS, Fu YH. Autosomal dominant leukodystrophy caused by lamin B1 duplications a clinical and molecular case study of altered nuclear function and disease. Methods Cell Biol 2010; 98:337-57. [PMID: 20816241 DOI: 10.1016/s0091-679x(10)98014-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Autosomal dominant leukodystrophy (ADLD) is an adult-onset demyelinating disorder that has recently shown to be caused by duplications of the nuclear lamina gene, lamin B1. This chapter attempts to collate and summarize the current knowledge about the disease and the clinical, pathological, and radiological presentations of the different ADLD families described till date. It also provides an overview of the molecular genetics underlying the disease and the mechanisms that may cause the duplication mutation event. ADLD is the first disease that has ever been linked to lamin B1 mutations and it expands the pathological role of the nuclear lamia to include disorders of the brain. The chapter also speculates on the different mechanisms that may link an important and ubiquitous structure like the nuclear lamina with the complex and cell-specific functions of myelin formation and maintenance. Understanding these mechanisms may not only prove helpful in understanding ADLD pathology but can also help in identifying new pathways that may be involved in myelin biology that can have implications for common demyelinating diseases like multiple sclerosis.
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Affiliation(s)
- Quasar Saleem Padiath
- Department of Neurology, University of California, San Francisco, San Francisco, California 94158, USA
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Puckelwartz MJ, Kessler EJ, Kim G, Dewitt MM, Zhang Y, Earley JU, Depreux FFS, Holaska J, Mewborn SK, Pytel P, McNally EM. Nesprin-1 mutations in human and murine cardiomyopathy. J Mol Cell Cardiol 2009; 48:600-8. [PMID: 19944109 DOI: 10.1016/j.yjmcc.2009.11.006] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Revised: 11/10/2009] [Accepted: 11/11/2009] [Indexed: 12/28/2022]
Abstract
Mutations in LMNA, the gene encoding the nuclear membrane proteins, lamins A and C, produce cardiac and muscle disease. In the heart, these autosomal dominant LMNA mutations lead to cardiomyopathy frequently associated with cardiac conduction system disease. Herein, we describe a patient with the R374H missense variant in nesprin-1alpha, a protein that binds lamin A/C. This individual developed dilated cardiomyopathy requiring cardiac transplantation. Fibroblasts from this individual had increased expression of nesprin-1alpha and lamins A and C, indicating changes in the nuclear membrane complex. We characterized mice lacking the carboxy-terminus of nesprin-1 since this model expresses nesprin-1 without its carboxy-terminal KASH domain. These Delta/DeltaKASH mice have a normally assembled but dysfunctional nuclear membrane complex and provide a model for nesprin-1 mutations. We found that Delta/DeltaKASH mice develop cardiomyopathy with associated cardiac conduction system disease. Older mutant animals were found to have elongated P wave duration, elevated atrial and ventricular effective refractory periods indicating conduction defects in the myocardium, and reduced fractional shortening. Cardiomyocyte nuclei were found to be elongated with reduced heterochromatin in the Delta/DeltaKASH hearts. These findings mirror what has been described from lamin A/C gene mutations and reinforce the importance of an intact nuclear membrane complex for a normally functioning heart.
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35
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Garcia-Arocena D, Yang JE, Brouwer JR, Tassone F, Iwahashi C, Berry-Kravis EM, Goetz CG, Sumis AM, Zhou L, Nguyen DV, Campos L, Howell E, Ludwig A, Greco C, Willemsen R, Hagerman RJ, Hagerman PJ. Fibroblast phenotype in male carriers of FMR1 premutation alleles. Hum Mol Genet 2009; 19:299-312. [PMID: 19864489 DOI: 10.1093/hmg/ddp497] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is an adult-onset neurodegenerative disorder among carriers of premutation expansions (55-200 CGG repeats) of the fragile X mental retardation 1 (FMR1) gene. The clinical features of FXTAS, as well as various forms of clinical involvement in carriers without FXTAS, are thought to arise through a direct toxic gain of function of high levels of FMR1 mRNA containing the expanded CGG repeat. Here we report a cellular endophenotype involving increased stress response (HSP27, HSP70 and CRYAB) and altered lamin A/C expression/organization in cultured skin fibroblasts from 11 male carriers of premutation alleles of the FMR1 gene, including six patients with FXTAS and five premutation carriers with no clinical evidence of FXTAS, compared with six controls. A similar abnormal cellular phenotype was found in CNS tissue from 10 patients with FXTAS. Finally, there is an analogous abnormal cellular distribution of lamin A/C isoforms in knock-in mice bearing the expanded CGG repeat in the murine Fmr1 gene. These alterations are evident even in mouse embryonic fibroblasts, raising the possibility that, in humans, the expanded-repeat mRNA triggers pathogenic mechanisms early in development, thus providing a molecular basis for the neurodevelopmental abnormalities observed in some children and clinical symptoms in some adults who are carriers of premutation FMR1 alleles. Cellular dysregulation in fibroblasts represents a novel and highly advantageous model for investigating disease pathogenesis in premutation carriers and for quantifying and monitoring disease progression. Fibroblast studies may also prove useful in screening and testing the efficacy of therapeutic interventions.
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Affiliation(s)
- Dolores Garcia-Arocena
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, CA 95616, USA
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36
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Wallace GQ, McNally EM. Mechanisms of muscle degeneration, regeneration, and repair in the muscular dystrophies. Annu Rev Physiol 2009; 71:37-57. [PMID: 18808326 DOI: 10.1146/annurev.physiol.010908.163216] [Citation(s) in RCA: 224] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
To withstand the rigors of contraction, muscle fibers have specialized protein complexes that buffer against mechanical stress and a multifaceted repair system that is rapidly activated after injury. Genetic studies first identified the mechanosensory signaling network that connects the structural elements of muscle and, more recently, have identified repair elements of muscle. Defects in the genes encoding the components of these systems lead to muscular dystrophy, a family of genetic disorders characterized by progressive muscle wasting. Although the age of onset, affected muscles, and severity vary considerably, all muscular dystrophies are characterized by muscle necrosis that overtakes the regenerative capacity of muscle. The resulting replacement of muscle by fatty and fibrous tissue leaves muscle increasingly weak and nonfunctional. This review discusses the cellular mechanisms that are primarily and secondarily disrupted in muscular dystrophy, focusing on membrane degeneration, muscle regeneration, and the repair of muscle.
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Affiliation(s)
- Gregory Q Wallace
- Department of Medicine, The University of Chicago, Chicago, Illinois 60637, 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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Fong LG, Vickers TA, Farber EA, Choi C, Yun UJ, Hu Y, Yang SH, Coffinier C, Lee R, Yin L, Davies BSJ, Andres DA, Spielmann HP, Bennett CF, Young SG. Activating the synthesis of progerin, the mutant prelamin A in Hutchinson-Gilford progeria syndrome, with antisense oligonucleotides. Hum Mol Genet 2009; 18:2462-71. [PMID: 19376814 PMCID: PMC2694694 DOI: 10.1093/hmg/ddp184] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Hutchinson-Gilford progeria syndrome (HGPS) is caused by point mutations that increase utilization of an alternate splice donor site in exon 11 of LMNA (the gene encoding lamin C and prelamin A). The alternate splicing reduces transcripts for wild-type prelamin A and increases transcripts for a truncated prelamin A (progerin). Here, we show that antisense oligonucleotides (ASOs) against exon 11 sequences downstream from the exon 11 splice donor site promote alternate splicing in both wild-type and HGPS fibroblasts, increasing the synthesis of progerin. Indeed, wild-type fibroblasts transfected with these ASOs exhibit progerin levels similar to (or greater than) those in fibroblasts from HGPS patients. This progerin was farnesylated, as judged by metabolic labeling studies. The synthesis of progerin in wild-type fibroblasts was accompanied by the same nuclear shape and gene-expression perturbations observed in HGPS fibroblasts. An ASO corresponding to the 5' portion of intron 11 also promoted alternate splicing. In contrast, an ASO against exon 11 sequences 5' to the alternate splice site reduced alternate splicing in HGPS cells and modestly lowered progerin levels. Thus, different ASOs can be used to increase or decrease 'HGPS splicing'. ASOs represent a new and powerful tool for recreating HGPS pathophysiology in wild-type cells.
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Affiliation(s)
- Loren G Fong
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.
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Does satellite cell dysfunction contribute to disease progression in Emery–Dreifuss muscular dystrophy? Biochem Soc Trans 2008; 36:1344-9. [DOI: 10.1042/bst0361344] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Muscular dystrophies comprise at least 34 conditions, characterized by progressive skeletal muscle weakness and degeneration. The loci affected include mutations in both muscle-specific genes and genes that are more widely expressed such as LMNA and EMD, responsible for EDMD (Emery–Dreifuss muscular dystrophy). LMNA encodes A-type lamins, whereas EMD encodes emerin, both located in the nuclear envelope. Mutation or loss of A-type lamins or emerin in the terminally differentiated myonuclei of muscle fibres results in muscle damage. Importantly, since LMNA and EMD are also expressed by the resident skeletal muscle stem cells, the satellite cells, the mutations that cause muscle damage may also directly compromise the regenerative response. Thus EDMD is different from dystrophic conditions such as Duchenne muscular dystrophy, where the mutated gene is only expressed in the muscle fibres. In this brief review, we examine the evidence that myoblasts carrying EDMD-causing mutations are compromised, and discuss the possibility that such dysfunction results in reduced efficiency of muscle regeneration, so actively contributes to disease progression.
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Puckelwartz MJ, Kessler E, Zhang Y, Hodzic D, Randles KN, Morris G, Earley JU, Hadhazy M, Holaska JM, Mewborn SK, Pytel P, McNally EM. Disruption of nesprin-1 produces an Emery Dreifuss muscular dystrophy-like phenotype in mice. Hum Mol Genet 2008; 18:607-20. [PMID: 19008300 DOI: 10.1093/hmg/ddn386] [Citation(s) in RCA: 149] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Mutations in the gene encoding the inner nuclear membrane proteins lamins A and C produce cardiac and skeletal muscle dysfunction referred to as Emery Dreifuss muscular dystrophy. Lamins A and C participate in the LINC complex that, along with the nesprin and SUN proteins, LInk the Nucleoskeleton with the Cytoskeleton. Nesprins 1 and 2 are giant spectrin-repeat containing proteins that have large and small forms. The nesprins contain a transmembrane anchor that tethers to the nuclear membrane followed by a short domain that resides within the lumen between the inner and outer nuclear membrane. Nesprin's luminal domain binds directly to SUN proteins. We generated mice where the C-terminus of nesprin-1 was deleted. This strategy produced a protein lacking the transmembrane and luminal domains that together are referred to as the KASH domain. Mice homozygous for this mutation exhibit lethality with approximately half dying at or near birth from respiratory failure. Surviving mice display hindlimb weakness and an abnormal gait. With increasing age, kyphoscoliosis, muscle pathology and cardiac conduction defects develop. The protein components of the LINC complex, including mutant nesprin-1alpha, lamin A/C and SUN2, are localized at the nuclear membrane in this model. However, the LINC components do not normally associate since coimmunoprecipitation experiments with SUN2 and nesprin reveal that mutant nesprin-1 protein no longer interacts with SUN2. These findings demonstrate the role of the LINC complex, and nesprin-1, in neuromuscular and cardiac disease.
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Drug-specific effect of nelfinavir and stavudine on primary culture of human preadipocytes. J Acquir Immune Defic Syndr 2008; 48:20-5. [PMID: 18344876 DOI: 10.1097/qai.0b013e31816b6aa4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Lipodystrophic syndrome is a major side effect of antiviral therapy leading to profound disturbances in adipose tissue. Human preadipocyte primary culture represents a model to understand mechanisms by which antiretroviral drugs alter adipocyte biology. The aim of this study was to evaluate the effects of various protease and nucleoside reverse transcriptase inhibitors in this model. We tested the effect of drugs on triglyceride accumulation and expression of specific genes by real-time polymerase chain reaction. To determine differential mechanisms by which the efficient drugs operate, we studied mitochondrial effects by evaluating oxygen consumption rates and nuclear lamina alteration by immunocytology. Only stavudine and nelfinavir, both at 10 microM, altered human adipose cell differentiation, as shown by reduced triglyceride accumulation. Our studies revealed that stavudine increased expression of genes such as PGC1 and LPL and affected mitochondrial respiration. Cells treated with nelfinavir had a lower expression of PPARgamma, LPL, and ap2 and presented disorganization of lamin A/C. Our data suggest for the first time in a model of human adipocytes differentiated in vitro that stavudine and nelfinavir interfere with the process of differentiation by 2 distinct mechanisms. This may be particularly relevant in understanding the physiopathologic mechanisms underlying the lipodystrophic syndrome.
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Dechat T, Pfleghaar K, Sengupta K, Shimi T, Shumaker DK, Solimando L, Goldman RD. Nuclear lamins: major factors in the structural organization and function of the nucleus and chromatin. Genes Dev 2008; 22:832-53. [PMID: 18381888 PMCID: PMC2732390 DOI: 10.1101/gad.1652708] [Citation(s) in RCA: 718] [Impact Index Per Article: 44.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Over the past few years it has become evident that the intermediate filament proteins, the types A and B nuclear lamins, not only provide a structural framework for the nucleus, but are also essential for many aspects of normal nuclear function. Insights into lamin-related functions have been derived from studies of the remarkably large number of disease-causing mutations in the human lamin A gene. This review provides an up-to-date overview of the functions of nuclear lamins, emphasizing their roles in epigenetics, chromatin organization, DNA replication, transcription, and DNA repair. In addition, we discuss recent evidence supporting the importance of lamins in viral infections.
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Affiliation(s)
- Thomas Dechat
- Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, Illinois 60611, USA
| | - Katrin Pfleghaar
- Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, Illinois 60611, USA
| | - Kaushik Sengupta
- Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, Illinois 60611, USA
| | - Takeshi Shimi
- Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, Illinois 60611, USA
| | - Dale K. Shumaker
- Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, Illinois 60611, USA
| | - Liliana Solimando
- Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, Illinois 60611, USA
| | - Robert D. Goldman
- Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, Illinois 60611, USA
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Håkelien AM, Delbarre E, Gaustad KG, Buendia B, Collas P. Expression of the myodystrophic R453W mutation of lamin A in C2C12 myoblasts causes promoter-specific and global epigenetic defects. Exp Cell Res 2008; 314:1869-80. [PMID: 18396274 DOI: 10.1016/j.yexcr.2008.02.018] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2008] [Revised: 02/22/2008] [Accepted: 02/26/2008] [Indexed: 10/22/2022]
Abstract
Autosomal dominant Emery-Dreifuss muscular dystrophy (EDMD) is characterized by muscle wasting and is caused by mutations in the LMNA gene encoding A-type lamins. Overexpression of the EDMD lamin A R453W mutation in C2C12 myoblasts impairs myogenic differentiation. We show here the influence of stable expression of the R453W and of the Dunnigan-type partial lipodystrophy R482W mutation of lamin A in C2C12 cells on transcription and epigenetic regulation of the myogenin (Myog) gene and on global chromatin organization. Expression of R453W-, but not R482W-lamin A, impairs activation of Myog and maintains a repressive chromatin state on the Myog promoter upon induction of differentiation, marked by H3 lysine (K) 9 dimethylation and failure to hypertrimethylate H3K4. Cells expressing WT-LaA also fail to hypertrimethylate H3K4. No defect occurs at the level of Myog promoter DNA methylation in any of the clones. Expression of R453W-lamin A and to a lesser extent R482W-lamin A in undifferentiated C2C12 cells redistributes H3K9me3 from pericentric heterochromatin. R453W-lamin A also elicits a redistribution of H3K27me3 from inactive X (Xi) and partial decondensation of Xi, but maintains Xist expression and coating of Xi, indicating that Xi remains inactivated. Our results argue that gene-specific and genome-wide chromatin rearrangements may constitute a molecular basis for laminopathies.
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Affiliation(s)
- Anne-Mari Håkelien
- Institute of Basic Medical Sciences, Department of Biochemistry, Faculty of Medicine, University of Oslo, PO Box 1112 Blindern, 0317 Oslo, Norway
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Dreuillet C, Harper M, Tillit J, Kress M, Ernoult-Lange M. Mislocalization of human transcription factor MOK2 in the presence of pathogenic mutations of lamin A/C. Biol Cell 2008; 100:51-61. [PMID: 17760566 DOI: 10.1042/bc20070053] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND INFORMATION hsMOK2 (human MOK2) is a DNA-binding transcriptional repressor. For example, it represses the IRBP (interphotoreceptor retinoid-binding protein) gene by competing with the CRX (cone-rod homeobox protein) transcriptional activator for DNA binding. Previous studies have shown an interaction between hsMOK2 and nuclear lamin A/C. This interaction could be important to explain hsMOK2 ability to repress transcription. RESULTS In the present study, we have tested whether missense pathogenic mutations of lamin A/C, which are located in the hsMOK2-binding domain, could affect the interaction with hsMOK2. We find that none of the tested mutations is able to disrupt hsMOK2 binding in vitro or in vivo. However, we observe an aberrant cellular localization of hsMOK2 into nuclear aggregates when pathogenic lamin A/C mutant proteins are expressed. CONCLUSIONS These results indicate that pathogenic mutations in lamin A/C lead to sequestration of hsMOK2 into nuclear aggregates, which may deregulate MOK2 target genes.
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Affiliation(s)
- Caroline Dreuillet
- CNRS-FRE2937, Institut André Lwoff, 7 rue Guy Môquet, 94801 Villejuif, France
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Parnaik VK. Role of Nuclear Lamins in Nuclear Organization, Cellular Signaling, and Inherited Diseases. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2008; 266:157-206. [DOI: 10.1016/s1937-6448(07)66004-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Kandert S, Lüke Y, Kleinhenz T, Neumann S, Lu W, Jaeger VM, Munck M, Wehnert M, Müller CR, Zhou Z, Noegel AA, Dabauvalle MC, Karakesisoglou I. Nesprin-2 giant safeguards nuclear envelope architecture in LMNA S143F progeria cells. Hum Mol Genet 2007; 16:2944-59. [PMID: 17881656 DOI: 10.1093/hmg/ddm255] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The S143F lamin A/C point mutation causes a phenotype combining features of myopathy and progeria. We demonstrate here that patient dermal fibroblast cells have dysmorphic nuclei containing numerous blebs and lobulations, which progressively accumulate as cells age in culture. The lamin A/C organization is altered, showing intranuclear and nuclear envelope (NE) aggregates and presenting often a honeycomb appearance. Immunofluorescence microscopy showed that nesprin-2 C-terminal isoforms and LAP2alpha were recovered in the cytoplasm, whereas LAP2beta and emerin were unevenly localized along the NE. In addition, the intranuclear organization of acetylated histones, histone H1 and the active form of RNA polymerase II were markedly different in patient cells. A subpopulation of mutant cells, however, expressing the 800 kDa nesprin-2 giant isoform, did not show an overt nuclear phenotype. Ectopic expression of p.S143F lamin A in fibroblasts recapitulates the patient cell phenotype, whereas no effects were observed in p.S143F LMNA keratinocytes, which highly express nesprin-2 giant. Overexpression of the mutant lamin A protein had a more severe impact on the NE of nesprin-2 giant deficient fibroblasts when compared with wild-type. In summary, our results suggest that the p.S143F lamin A mutation affects NE architecture and composition, chromatin organization, gene expression and transcription. Furthermore, our findings implicate a direct involvement of the nesprins in laminopathies and propose nesprin-2 giant as a structural reinforcer at the NE.
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Affiliation(s)
- Sebastian Kandert
- Department of Cell and Developmental Biology, University of Würzburg, D97074, Würzburg, Germany
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Huang S, Risques RA, Martin GM, Rabinovitch PS, Oshima J. Accelerated telomere shortening and replicative senescence in human fibroblasts overexpressing mutant and wild-type lamin A. Exp Cell Res 2007; 314:82-91. [PMID: 17870066 PMCID: PMC2228272 DOI: 10.1016/j.yexcr.2007.08.004] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2007] [Revised: 07/25/2007] [Accepted: 08/08/2007] [Indexed: 01/08/2023]
Abstract
LMNA mutations are responsible for a variety of genetic disorders, including muscular dystrophy, lipodystrophy, and certain progeroid syndromes, notably Hutchinson-Gilford Progeria. Although a number of clinical features of these disorders are suggestive of accelerated aging, it is not known whether cells derived from these patients exhibit cellular phenotypes associated with accelerated aging. We examined a series of isogenic skin fibroblast lines transfected with LMNA constructs bearing known pathogenic point mutations or deletion mutations found in progeroid syndromes. Fibroblasts overexpressing mutant lamin A exhibited accelerated rates of loss of telomeres and shortened replicative lifespans, in addition to abnormal nuclear morphology. To our surprise, these abnormalities were also observed in lines overexpressing wild-type lamin A. Copy number variants are common in human populations; those involving LMNA, whether arising meiotically or mitotically, might lead to progeroid phenotypes. In an initial pilot study of 23 progeroid cases without detectable WRN or LMNA mutations, however, no cases of altered LMNA copy number were detected. Nevertheless, our findings raise a hypothesis that changes in lamina organization may cause accelerated telomere attrition, with different kinetics for overexpession of wild-type and mutant lamin A, which leads to rapid replicative senescence and progroid phenotypes.
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Affiliation(s)
| | | | | | | | - Junko Oshima
- *Corresponding author: Junko Oshima, Department of Pathology, Box 357470, University of Washington, 1959 NE Pacific Ave, Seattle, WA 98195-7470, Tel: (206) 616-4227, Fax: (206) 685-8356, E-mail:
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Abstract
Histone modifications such as acetylation, methylation and phosphorylation have been implicated in fundamental cellular processes such as epigenetic regulation of gene expression, organization of chromatin structure, chromosome segregation, DNA replication and DNA repair. Males absent on the first (MOF) is responsible for acetylating histone H4 at lysine 16 (H4K16) and is a key component of the MSL complex required for dosage compensation in Drosophila. The human ortholog of MOF (hMOF) has the same substrate specificity and recent purification of the human and Drosophila MOF complexes showed that these complexes were also highly conserved through evolution. Several studies have shown that loss of hMOF in mammalian cells leads to a number of different phenotypes; a G2/M cell cycle arrest, nuclear morphological defects, spontaneous chromosomal aberrations, reduced transcription of certain genes and an impaired DNA repair response upon ionizing irradiation. Moreover, hMOF is involved in ATM activation in response to DNA damage and acetylation of p53 by hMOF influences the cell's decision to undergo apoptosis instead of a cell cycle arrest. These data, highlighting hMOF as an important component of many cellular processes, as well as links between hMOF and cancer will be discussed.
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Affiliation(s)
- S Rea
- Gene Expression Programme, European Molecular Biology Laboratory, Heidelberg, Germany
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Muñoz-Alarcón A, Pavlovic M, Wismar J, Schmitt B, Eriksson M, Kylsten P, Dushay MS. Characterization of lamin mutation phenotypes in Drosophila and comparison to human laminopathies. PLoS One 2007; 2:e532. [PMID: 17565385 PMCID: PMC1885830 DOI: 10.1371/journal.pone.0000532] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2007] [Accepted: 05/18/2007] [Indexed: 11/19/2022] Open
Abstract
Lamins are intermediate filament proteins that make up the nuclear lamina, a matrix underlying the nuclear membrane in all metazoan cells that is important for nuclear form and function. Vertebrate A-type lamins are expressed in differentiating cells, while B-type lamins are expressed ubiquitously. Drosophila has two lamin genes that are expressed in A- and B-type patterns, and it is assumed that similarly expressed lamins perform similar functions. However, Drosophila and vertebrate lamins are not orthologous, and their expression patterns evolved independently. It is therefore of interest to examine the effects of mutations in lamin genes. Mutations in the mammalian lamin A/C gene cause a range of diseases, collectively called laminopathies, that include muscular dystrophies and premature aging disorders. We compared the sequences of lamin genes from different species, and we have characterized larval and adult phenotypes in Drosophila bearing mutations in the lam gene that is expressed in the B-type pattern. Larvae move less and show subtle muscle defects, and surviving lam adults are flightless and walk like aged wild-type flies, suggesting that lam phenotypes might result from neuromuscular defects, premature aging, or both. The resemblance of Drosophila lam phenotypes to human laminopathies suggests that some lamin functions may be performed by differently expressed genes in flies and mammals. Such still-unknown functions thus would not be dependent on lamin gene expression pattern, suggesting the presence of other lamin functions that are expression dependent. Our results illustrate a complex interplay between lamin gene expression and function through evolution.
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Affiliation(s)
- Andrés Muñoz-Alarcón
- Department of Life Sciences, Södertörns högskola, Huddinge, Sweden
- Department of Biosciences and Nutrition, Karolinska Institute, Stockholm, Sweden
| | - Maja Pavlovic
- Department of Life Sciences, Södertörns högskola, Huddinge, Sweden
- Department of Biosciences and Nutrition, Karolinska Institute, Stockholm, Sweden
| | - Jasmine Wismar
- Max-Planck-Institut für Hirnforschung, Abteilung Neurochemie, Frankfurt, Germany
| | - Bertram Schmitt
- Max-Planck-Institut für Hirnforschung, Abteilung Neurochemie, Frankfurt, Germany
| | - Maria Eriksson
- Department of Biosciences and Nutrition, Karolinska Institute, Stockholm, Sweden
| | - Per Kylsten
- Department of Life Sciences, Södertörns högskola, Huddinge, Sweden
| | - Mitchell S. Dushay
- Department of Life Sciences, Södertörns högskola, Huddinge, Sweden
- Department of Comparative Physiology, EBC, Uppsala University, Uppsala, Sweden
- * To whom correspondence should be addressed. E-mail:
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Worman HJ, Bonne G. "Laminopathies": a wide spectrum of human diseases. Exp Cell Res 2007; 313:2121-33. [PMID: 17467691 PMCID: PMC2964355 DOI: 10.1016/j.yexcr.2007.03.028] [Citation(s) in RCA: 472] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2007] [Revised: 03/08/2007] [Accepted: 03/12/2007] [Indexed: 12/23/2022]
Abstract
Mutations in genes encoding the intermediate filament nuclear lamins and associated proteins cause a wide spectrum of diseases sometimes called "laminopathies." Diseases caused by mutations in LMNA encoding A-type lamins include autosomal dominant Emery-Dreifuss muscular dystrophy and related myopathies, Dunnigan-type familial partial lipodystrophy, Charcot-Marie-Tooth disease type 2B1 and developmental and accelerated aging disorders. Duplication in LMNB1 encoding lamin B1 causes autosomal dominant leukodystrophy and mutations in LMNB2 encoding lamin B2 are associated with acquired partial lipodystrophy. Disorders caused by mutations in genes encoding lamin-associated integral inner nuclear membrane proteins include X-linked Emery-Dreifuss muscular dystrophy, sclerosing bone dysplasias, HEM/Greenberg skeletal dysplasia and Pelger-Huet anomaly. While mutations and clinical phenotypes of "laminopathies" have been carefully described, data explaining pathogenic mechanisms are only emerging. Future investigations will likely identify new "laminopathies" and a combination of basic and clinical research will lead to a better understanding of pathophysiology and the development of therapies.
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Affiliation(s)
- Howard J Worman
- Department of Medicine, College of Physicians and Surgeons, Columbia University, 630 West 168th Street, New York, NY 10032, USA.
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