1
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Zhang Y, Lin Y, Zhang Y, Wang Y, Li Z, Zhu Y, Liu H, Ju W, Cui C, Chen M. Familial atrial myopathy in a large multigenerational heart-hand syndrome pedigree carrying an LMNA missense variant in rod 2B domain (p.R335W). Heart Rhythm 2021; 19:466-475. [PMID: 34808346 DOI: 10.1016/j.hrthm.2021.11.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 11/14/2021] [Accepted: 11/16/2021] [Indexed: 02/02/2023]
Abstract
BACKGROUND The literature on laminopathy with ventricular phenotype is extensive. However, the pathogenicity of LMNA variations in atrial lesions still lacks research. OBJECTIVE The purpose of this study was to characterize the atrial phenotypes and possible mechanisms in a large Chinese family with heart-hand syndrome carrying a LMNA missense variant in rod 2B domain (c.1003C>T p.R335W). METHODS Clinical characteristics were collected on the basis of the pedigree investigation. Comprehensive functional analyses, including molecular dynamic (MD) simulation, cellular, and animal functional assays, determined the pathogenicity in atrial myopathy. RESULTS In the pedigree investigation, 6 of 13 of the mutation carriers showed heterogeneous cardiac phenotypes and 8 carriers also had brachydactyly. In silico molecular dynamics simulations predicted increased binding energy of the R335W mutant lamin A. Atrial cardiomyocytes (HL-1, human induced pluripotent stem cell-derived atrial cardiomyocytes) expressing R335W showed abnormal nuclear morphology, compromised DNA repair, and dysfunctional contraction. Adult zebrafish expressing mutant lamin A showed increased P wave duration in the electrocardiogram, decreased peak A wave velocity in echocardiography, and atrial lesions under the transmission electron microscope. CONCLUSION LMNA p.R335W mutation leads to familial heart-hand syndrome characterized by an overlapping phenotype of prominent atrial lesions and brachydactyly. The unstable lamin dimerization and impaired DNA repair are possible mechanisms underlying cardiac phenotypes. Our findings consolidated the genetic role in the course of atrial arrhythmias and cardiac aging, which is helpful in the diagnosis and treatment of cardiac laminopathy.
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Affiliation(s)
- Yike Zhang
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Yongping Lin
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Yanjuan Zhang
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Yuanqing Wang
- Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Zhaomin Li
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Yue Zhu
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Hailei Liu
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Weizhu Ju
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Chang Cui
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
| | - Minglong Chen
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China; Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center for Cardiovascular Disease Translational Medicine, Nanjing Medical University, Nanjing, China.
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2
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Dubik N, Mai S. Lamin A/C: Function in Normal and Tumor Cells. Cancers (Basel) 2020; 12:cancers12123688. [PMID: 33316938 PMCID: PMC7764147 DOI: 10.3390/cancers12123688] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 12/07/2020] [Accepted: 12/08/2020] [Indexed: 02/07/2023] Open
Abstract
Simple Summary The aim of this review is to summarize lamin A/C’s currently known functions in both normal and diseased cells. Lamin A/C is a nuclear protein with many functions in cells, such as maintaining a cell’s structural stability, cell motility, mechanosensing, chromosome organization, gene regulation, cell differentiation, DNA damage repair, and telomere protection. Mutations of the lamin A/C gene, incorrect processing of the protein, and lamin A/C deregulation can lead to various diseases and cancer. This review touches on diseases caused by mutation and incorrect processing of lamin A/C, called laminopathies. The effect of lamin A/C deregulation in cancer is also reviewed, and lamin A/C’s potential in helping to diagnose prostate cancers more accurately is discussed. Abstract This review is focused on lamin A/C, a nuclear protein with multiple functions in normal and diseased cells. Its functions, as known to date, are summarized. This summary includes its role in maintaining a cell’s structural stability, cell motility, mechanosensing, chromosome organization, gene regulation, cell differentiation, DNA damage repair, and telomere protection. As lamin A/C has a variety of critical roles within the cell, mutations of the lamin A/C gene and incorrect processing of the protein results in a wide variety of diseases, ranging from striated muscle disorders to accelerated aging diseases. These diseases, collectively termed laminopathies, are also touched upon. Finally, we review the existing evidence of lamin A/C’s deregulation in cancer. Lamin A/C deregulation leads to various traits, including genomic instability and increased tolerance to mechanical insult, which can lead to more aggressive cancer and poorer prognosis. As lamin A/C’s expression in specific cancers varies widely, currently known lamin A/C expression in various cancers is reviewed. Additionally, Lamin A/C’s potential as a biomarker in various cancers and as an aid in more accurately diagnosing intermediate Gleason score prostate cancers is also discussed.
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3
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Lamin A/C Mechanotransduction in Laminopathies. Cells 2020; 9:cells9051306. [PMID: 32456328 PMCID: PMC7291067 DOI: 10.3390/cells9051306] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/20/2020] [Accepted: 05/22/2020] [Indexed: 12/14/2022] Open
Abstract
Mechanotransduction translates forces into biological responses and regulates cell functionalities. It is implicated in several diseases, including laminopathies which are pathologies associated with mutations in lamins and lamin-associated proteins. These pathologies affect muscle, adipose, bone, nerve, and skin cells and range from muscular dystrophies to accelerated aging. Although the exact mechanisms governing laminopathies and gene expression are still not clear, a strong correlation has been found between cell functionality and nuclear behavior. New theories base on the direct effect of external force on the genome, which is indeed sensitive to the force transduced by the nuclear lamina. Nuclear lamina performs two essential functions in mechanotransduction pathway modulating the nuclear stiffness and governing the chromatin remodeling. Indeed, A-type lamin mutation and deregulation has been found to affect the nuclear response, altering several downstream cellular processes such as mitosis, chromatin organization, DNA replication-transcription, and nuclear structural integrity. In this review, we summarize the recent findings on the molecular composition and architecture of the nuclear lamina, its role in healthy cells and disease regulation. We focus on A-type lamins since this protein family is the most involved in mechanotransduction and laminopathies.
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4
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Lamin A/C Assembly Defects in LMNA-Congenital Muscular Dystrophy Is Responsible for the Increased Severity of the Disease Compared with Emery-Dreifuss Muscular Dystrophy. Cells 2020; 9:cells9040844. [PMID: 32244403 PMCID: PMC7226786 DOI: 10.3390/cells9040844] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 03/24/2020] [Accepted: 03/27/2020] [Indexed: 01/13/2023] Open
Abstract
LMNA encodes for Lamin A/C, type V intermediate filaments that polymerize under the inner nuclear membrane to form the nuclear lamina. A small fraction of Lamin A/C, less polymerized, is also found in the nucleoplasm. Lamin A/C functions include roles in nuclear resistance to mechanical stress and gene regulation. LMNA mutations are responsible for a wide variety of pathologies, including Emery–Dreifuss (EDMD) and LMNA-related congenital muscular dystrophies (L-CMD) without clear genotype–phenotype correlations. Both diseases presented with striated muscle disorders although L-CMD symptoms appear much earlier and are more severe. Seeking for pathomechanical differences to explain the severity of L-CMD mutations, we performed an in silico analysis of the UMD-LMNA database and found that L-CMD mutations mainly affect residues involved in Lamin dimer and tetramer stability. In line with this, we found increased nucleoplasmic Lamin A/C in L-CMD patient fibroblasts and mouse myoblasts compared to the control and EDMD. L-CMD myoblasts show differentiation defects linked to their inability to upregulate muscle specific nuclear envelope (NE) proteins expression. NE proteins were mislocalized, leading to misshapen nuclei. We conclude that these defects are due to both the absence of Lamin A/C from the nuclear lamina and its maintenance in the nucleoplasm of myotubes.
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5
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Bianchi A, Manti PG, Lucini F, Lanzuolo C. Mechanotransduction, nuclear architecture and epigenetics in Emery Dreifuss Muscular Dystrophy: tous pour un, un pour tous. Nucleus 2019; 9:276-290. [PMID: 29619865 PMCID: PMC5973142 DOI: 10.1080/19491034.2018.1460044] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The alteration of the several roles that Lamin A/C plays in the mammalian cell leads to a broad spectrum of pathologies that – all together – are named laminopathies. Among those, the Emery Dreifuss Muscular Dystrophy (EDMD) is of particular interest as, despite the several known mutations of Lamin A/C, the genotype–phenotype correlation still remains poorly understood; this suggests that the epigenetic background of patients might play an important role during the time course of the disease. Historically, both a mechanical role of Lamin A/C and a regulative one have been suggested as the driving force of laminopathies; however, those two hypotheses are not mutually exclusive. Recent scientific evidence shows that Lamin A/C sustains the correct gene expression at the epigenetic level thanks to the Lamina Associated Domains (LADs) reorganization and the crosstalk with the Polycomb Group of Proteins (PcG). Furthermore, the PcG-dependent histone mark H3K27me3 increases under mechanical stress, finally pointing out the link between the mechano-properties of the nuclear lamina and epigenetics. Here, we summarize the emerging mechanisms that could explain the high variability seen in Emery Dreifuss muscular dystrophy.
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Affiliation(s)
- Andrea Bianchi
- a CNR Institute of Cell Biology and Neurobiology, Istituto di Ricovero e Cura a Carattere Scientifico Fondazione Santa Lucia , Rome , Italy.,b Istituto Nazionale Genetica Molecolare Romeo ed Enrica Invernizzi , Milan , Italy
| | | | - Federica Lucini
- b Istituto Nazionale Genetica Molecolare Romeo ed Enrica Invernizzi , Milan , Italy
| | - Chiara Lanzuolo
- a CNR Institute of Cell Biology and Neurobiology, Istituto di Ricovero e Cura a Carattere Scientifico Fondazione Santa Lucia , Rome , Italy.,b Istituto Nazionale Genetica Molecolare Romeo ed Enrica Invernizzi , Milan , Italy.,c Istituto di Ricovero e Cura a Carattere Scientifico Fondazione Santa Lucia , Rome , Italy
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6
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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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7
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Next-Generation Sequencing to Diagnose Muscular Dystrophy, Rhabdomyolysis, and HyperCKemia. Can J Neurol Sci 2018; 45:262-268. [DOI: 10.1017/cjn.2017.286] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
AbstractBackground:Neuromuscular disorders are a phenotypically and genotypically diverse group of diseases that can be difficult to diagnose accurately because of overlapping clinical features and nonspecific muscle pathology. Next-generation sequencing (NGS) is a high-throughput technology that can be used as a more time- and cost-effective tool for identifying molecular diagnoses for complex genetic conditions, such as neuromuscular disorders.Methods:One hundred and sixty-nine patients referred to a Canadian neuromuscular clinic for evaluation of possible muscle disease were screened with an NGS panel of muscular dystrophy–associated genes. Patients were categorized by the reason of referral (1) muscle weakness (n=135), (2) recurrent episodes of rhabdomyolysis (n=18), or (3) idiopathic hyperCKemia (n=16).Results:Pathogenic and likely pathogenic variants were identified in 36.09% of patients (61/169). The detection rate was 37.04% (50/135) in patients with muscle weakness, 33.33% (6/18) with rhabdomyolysis, and 31.25% (5/16) in those with idiopathic hyperCKemia.Conclusions:This study shows that NGS can be a useful tool in the molecular workup of patients seen in a neuromuscular clinic. Evaluating the utility of large panels of a muscle disease-specific NGS panel to investigate the genetic susceptibilities of rhabdomyolysis and/or idiopathic hyperCKemia is a relatively new field. Twenty-eight of the pathogenic and likely pathogenic variants reported here are novel and have not previously been associated with disease.
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8
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Hoorntje ET, Bollen IA, Barge-Schaapveld DQ, van Tienen FH, Te Meerman GJ, Jansweijer JA, van Essen AJ, Volders PG, Constantinescu AA, van den Akker PC, van Spaendonck-Zwarts KY, Oldenburg RA, Marcelis CL, van der Smagt JJ, Hennekam EA, Vink A, Bootsma M, Aten E, Wilde AA, van den Wijngaard A, Broers JL, Jongbloed JD, van der Velden J, van den Berg MP, van Tintelen JP. Lamin A/C-Related Cardiac Disease: Late Onset With a Variable and Mild Phenotype in a Large Cohort of Patients With the Lamin A/C p.(Arg331Gln) Founder Mutation. ACTA ACUST UNITED AC 2018; 10:CIRCGENETICS.116.001631. [PMID: 28790152 DOI: 10.1161/circgenetics.116.001631] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2016] [Accepted: 05/08/2017] [Indexed: 11/16/2022]
Abstract
BACKGROUND Interpretation of missense variants can be especially difficult when the variant is also found in control populations. This is what we encountered for the LMNA c.992G>A (p.(Arg331Gln)) variant. Therefore, to evaluate the effect of this variant, we combined an evaluation of clinical data with functional experiments and morphological studies. METHODS AND RESULTS Clinical data of 23 probands and 35 family members carrying this variant were retrospectively collected. A time-to-event analysis was performed to compare the course of the disease with carriers of other LMNA mutations. Myocardial biopsies were studied with electron microscopy and by measuring force development of the sarcomeres. Morphology of the nuclear envelope was assessed with immunofluorescence on cultured fibroblasts. The phenotype in probands and family members was characterized by atrioventricular conduction disturbances (61% and 44%, respectively), supraventricular arrhythmias (69% and 52%, respectively), and dilated cardiomyopathy (74% and 14%, respectively). LMNA p.(Arg331Gln) carriers had a significantly better outcome regarding the composite end point (malignant ventricular arrhythmias, end-stage heart failure, or death) compared with carriers of other pathogenic LMNA mutations. A shared haplotype of 1 Mb around LMNA suggested a common founder. The combined logarithm of the odds score was 3.46. Force development in membrane-permeabilized cardiomyocytes was reduced because of decreased myofibril density. Structural nuclear LMNA-associated envelope abnormalities, that is, blebs, were confirmed by electron microscopy and immunofluorescence microscopy. CONCLUSIONS Clinical, morphological, functional, haplotype, and segregation data all indicate that LMNA p.(Arg331Gln) is a pathogenic founder mutation with a phenotype reminiscent of other LMNA mutations but with a more benign course.
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Affiliation(s)
| | - Ilse A Bollen
- For the author affiliations, please see the Appendix
| | | | | | | | | | | | | | | | | | | | | | | | | | | | - Aryan Vink
- For the author affiliations, please see the Appendix
| | | | - Emmelien Aten
- For the author affiliations, please see the Appendix
| | | | | | - Jos L Broers
- For the author affiliations, please see the Appendix
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9
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Nishiuchi S, Makiyama T, Aiba T, Nakajima K, Hirose S, Kohjitani H, Yamamoto Y, Harita T, Hayano M, Wuriyanghai Y, Chen J, Sasaki K, Yagihara N, Ishikawa T, Onoue K, Murakoshi N, Watanabe I, Ohkubo K, Watanabe H, Ohno S, Doi T, Shizuta S, Minamino T, Saito Y, Oginosawa Y, Nogami A, Aonuma K, Kusano K, Makita N, Shimizu W, Horie M, Kimura T. Gene-Based Risk Stratification for Cardiac Disorders in
LMNA
Mutation Carriers. ACTA ACUST UNITED AC 2017; 10:CIRCGENETICS.116.001603. [DOI: 10.1161/circgenetics.116.001603] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 09/25/2017] [Indexed: 01/01/2023]
Abstract
Background—
Mutations in
LMNA
(
lamin A/C
), which encodes lamin A and C, typically cause age-dependent cardiac phenotypes, including dilated cardiomyopathy, cardiac conduction disturbance, atrial fibrillation, and malignant ventricular arrhythmias. Although the type of
LMNA
mutations have been reported to be associated with susceptibility to malignant ventricular arrhythmias, the gene-based risk stratification for cardiac complications remains unexplored.
Methods and Results—
The multicenter cohort included 77
LMNA
mutation carriers from 45 families; cardiac disorders were retrospectively analyzed. The mean age of patients when they underwent genetic testing was 45±17, and they were followed for a median 49 months. Of the 77 carriers, 71 (92%) were phenotypically affected and showed cardiac conduction disturbance (81%), low left ventricular ejection fraction (<50%; 45%), atrial arrhythmias (58%), and malignant ventricular arrhythmias (26%). During the follow-up period, 9 (12%) died, either from end-stage heart failure (n=7) or suddenly (n=2). Genetic analysis showed truncation mutations in 58 patients from 31 families and missense mutations in 19 patients from 14 families. The onset of cardiac disorders indicated that subjects with truncation mutations had an earlier occurrence of cardiac conduction disturbance and low left ventricular ejection fraction, than those with missense mutations. In addition, the truncation mutation was found to be a risk factor for the early onset of cardiac conduction disturbance and the occurrence of atrial arrhythmias and low left ventricular ejection fraction, as estimated using multivariable analyses.
Conclusions—
The truncation mutations were associated with manifestation of cardiac phenotypes in
LMNA
-related cardiomyopathy, suggesting that genetic analysis might be useful for diagnosis and risk stratification.
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10
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Bollen IAE, Schuldt M, Harakalova M, Vink A, Asselbergs FW, Pinto JR, Krüger M, Kuster DWD, van der Velden J. Genotype-specific pathogenic effects in human dilated cardiomyopathy. J Physiol 2017; 595:4677-4693. [PMID: 28436080 PMCID: PMC5509872 DOI: 10.1113/jp274145] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 04/18/2017] [Indexed: 01/09/2023] Open
Abstract
KEY POINTS Mutations in genes encoding cardiac troponin I (TNNI3) and cardiac troponin T (TNNT2) caused altered troponin protein stoichiometry in patients with dilated cardiomyopathy. TNNI3p.98trunc resulted in haploinsufficiency, increased Ca2+ -sensitivity and reduced length-dependent activation. TNNT2p.K217del caused increased passive tension. A mutation in the gene encoding Lamin A/C (LMNAp.R331Q ) led to reduced maximal force development through secondary disease remodelling in patients suffering from dilated cardiomyopathy. Our study shows that different gene mutations induce dilated cardiomyopathy via diverse cellular pathways. ABSTRACT Dilated cardiomyopathy (DCM) can be caused by mutations in sarcomeric and non-sarcomeric genes. In this study we defined the pathogenic effects of three DCM-causing mutations: the sarcomeric mutations in genes encoding cardiac troponin I (TNNI3p.98truncation ) and cardiac troponin T (TNNT2p.K217deletion ; also known as the p.K210del) and the non-sarcomeric gene mutation encoding lamin A/C (LMNAp.R331Q ). We assessed sarcomeric protein expression and phosphorylation and contractile behaviour in single membrane-permeabilized cardiomyocytes in human left ventricular heart tissue. Exchange with recombinant troponin complex was used to establish the direct pathogenic effects of the mutations in TNNI3 and TNNT2. The TNNI3p.98trunc and TNNT2p.K217del mutation showed reduced expression of troponin I to 39% and 51%, troponin T to 64% and 53%, and troponin C to 73% and 97% of controls, respectively, and altered stoichiometry between the three cardiac troponin subunits. The TNNI3p.98trunc showed pure haploinsufficiency, increased Ca2+ -sensitivity and impaired length-dependent activation. The TNNT2p.K217del mutation showed a significant increase in passive tension that was not due to changes in titin isoform composition or phosphorylation. Exchange with wild-type troponin complex corrected troponin protein levels to 83% of controls in the TNNI3p.98trunc sample. Moreover, upon exchange all functional deficits in the TNNI3p.98trunc and TNNT2p.K217del samples were normalized to control values confirming the pathogenic effects of the troponin mutations. The LMNAp.R331Q mutation resulted in reduced maximal force development due to disease remodelling. Our study shows that different gene mutations induce DCM via diverse cellular pathways.
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Affiliation(s)
- Ilse A E Bollen
- Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Center, Amsterdam, the Netherlands
| | - Maike Schuldt
- Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Center, Amsterdam, the Netherlands
| | - Magdalena Harakalova
- Department of Cardiology, Division of Heart and Lungs, University of Utrecht, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Aryan Vink
- Department of Pathology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Folkert W Asselbergs
- Department of Cardiology, Division of Heart and Lungs, University of Utrecht, University Medical Center Utrecht, Utrecht, the Netherlands.,Durrer Center for Cardiogenetic Research, ICIN-Netherlands Heart Institute, Utrecht, the Netherlands.,Institute of Cardiovascular Science, Faculty of Population Health Sciences, University College London, London, UK
| | - Jose R Pinto
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL, USA
| | - Martina Krüger
- Institute of Cardiovascular Physiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Diederik W D Kuster
- Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Center, Amsterdam, the Netherlands
| | - Jolanda van der Velden
- Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Center, Amsterdam, the Netherlands.,Netherlands Heart Institute, Utrecht, the Netherlands
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11
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Gruenbaum Y, Foisner R. Lamins: nuclear intermediate filament proteins with fundamental functions in nuclear mechanics and genome regulation. Annu Rev Biochem 2015; 84:131-64. [PMID: 25747401 DOI: 10.1146/annurev-biochem-060614-034115] [Citation(s) in RCA: 368] [Impact Index Per Article: 40.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Lamins are intermediate filament proteins that form a scaffold, termed nuclear lamina, at the nuclear periphery. A small fraction of lamins also localize throughout the nucleoplasm. Lamins bind to a growing number of nuclear protein complexes and are implicated in both nuclear and cytoskeletal organization, mechanical stability, chromatin organization, gene regulation, genome stability, differentiation, and tissue-specific functions. The lamin-based complexes and their specific functions also provide insights into possible disease mechanisms for human laminopathies, ranging from muscular dystrophy to accelerated aging, as observed in Hutchinson-Gilford progeria and atypical Werner syndromes.
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Affiliation(s)
- Yosef Gruenbaum
- Department of Genetics, Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem 91904, Israel;
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12
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Chernyatina AA, Guzenko D, Strelkov SV. Intermediate filament structure: the bottom-up approach. Curr Opin Cell Biol 2015; 32:65-72. [DOI: 10.1016/j.ceb.2014.12.007] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 12/05/2014] [Accepted: 12/19/2014] [Indexed: 11/24/2022]
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13
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Kaminski A, Fedorchak GR, Lammerding J. The cellular mastermind(?)-mechanotransduction and the nucleus. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 126:157-203. [PMID: 25081618 PMCID: PMC4591053 DOI: 10.1016/b978-0-12-394624-9.00007-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cells respond to mechanical stimulation by activation of specific signaling pathways and genes that allow the cell to adapt to its dynamic physical environment. How cells sense the various mechanical inputs and translate them into biochemical signals remains an area of active investigation. Recent reports suggest that the cell nucleus may be directly implicated in this cellular mechanotransduction process. Taken together, these findings paint a picture of the nucleus as a central hub in cellular mechanotransduction-both structurally and biochemically-with important implications in physiology and disease.
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Affiliation(s)
- Ashley Kaminski
- Department of Biomedical Engineering & Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York, USA
| | - Gregory R Fedorchak
- Department of Biomedical Engineering & Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York, USA
| | - Jan Lammerding
- Department of Biomedical Engineering & Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York, USA
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Ciska M, Moreno Díaz de la Espina S. The intriguing plant nuclear lamina. FRONTIERS IN PLANT SCIENCE 2014; 5:166. [PMID: 24808902 PMCID: PMC4010787 DOI: 10.3389/fpls.2014.00166] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 04/08/2014] [Indexed: 05/19/2023]
Abstract
The nuclear lamina is a complex protein mesh attached to the inner nuclear membrane (INM), which is also associated with nuclear pore complexes. It provides mechanical support to the nucleus and nuclear envelope, and as well as facilitating the connection of the nucleoskeleton to the cytoskeleton, it is also involved in chromatin organization, gene regulation, and signaling. In metazoans, the nuclear lamina consists of a polymeric layer of lamins and other interacting proteins responsible for its association with the INM and chromatin. In plants, field emission scanning electron microscopy of nuclei, and thin section transmission electron microscopy of isolated nucleoskeletons, reveals the lamina to have a similar structure to that of metazoans. Moreover, although plants lack lamin genes and the genes encoding most lamin-binding proteins, the main functions of the lamina are fulfilled in plants. Hence, it would appear that the plant lamina is not based on lamins and that other proteins substitute for lamins in plant cells. The nuclear matrix constituent proteins are the best characterized structural proteins in the plant lamina. Although these proteins do not display strong sequence similarity to lamins, their predicted secondary structure and sub-nuclear distribution, as well as their influence on nuclear size and shape, and on heterochromatin organization, suggest they could be functional lamin analogs. In this review we shall summarize what is currently known about the organization and composition of the plant nuclear lamina and its interacting complexes, and we will discuss the activity of this structure in the plant cell and its nucleus.
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Affiliation(s)
| | - Susana Moreno Díaz de la Espina
- *Correspondence: Susana Moreno Díaz de la Espina, Department of Cell and Molecular Biology, Biological Research Centre – Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040 Madrid, Spain e-mail:
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Scharner J, Lu HC, Fraternali F, Ellis JA, Zammit PS. Mapping disease-related missense mutations in the immunoglobulin-like fold domain of lamin A/C reveals novel genotype-phenotype associations for laminopathies. Proteins 2013; 82:904-15. [DOI: 10.1002/prot.24465] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 10/11/2013] [Accepted: 10/21/2013] [Indexed: 11/06/2022]
Affiliation(s)
- Juergen Scharner
- Randall Division of Cell and Molecular Biophysics; King's College London; London SE1 1UL United Kingdom
| | - Hui-Chun Lu
- Randall Division of Cell and Molecular Biophysics; King's College London; London SE1 1UL United Kingdom
| | - Franca Fraternali
- Randall Division of Cell and Molecular Biophysics; King's College London; London SE1 1UL United Kingdom
| | - Juliet A. Ellis
- Randall Division of Cell and Molecular Biophysics; King's College London; London SE1 1UL United Kingdom
| | - Peter S. Zammit
- Randall Division of Cell and Molecular Biophysics; King's College London; London SE1 1UL United Kingdom
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Davidson PM, Lammerding J. Broken nuclei--lamins, nuclear mechanics, and disease. Trends Cell Biol 2013; 24:247-56. [PMID: 24309562 DOI: 10.1016/j.tcb.2013.11.004] [Citation(s) in RCA: 187] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 11/04/2013] [Accepted: 11/06/2013] [Indexed: 11/19/2022]
Abstract
Mutations in lamins, which are ubiquitous nuclear intermediate filaments, lead to a variety of disorders including muscular dystrophy and dilated cardiomyopathy. Lamins provide nuclear stability, help connect the nucleus to the cytoskeleton, and can modulate chromatin organization and gene expression. Nonetheless, the diverse functions of lamins remain incompletely understood. We focus here on the role of lamins on nuclear mechanics and their involvement in human diseases. Recent findings suggest that lamin mutations can decrease nuclear stability, increase nuclear fragility, and disturb mechanotransduction signaling, possibly explaining the muscle-specific defects in many laminopathies. At the same time, altered lamin expression has been reported in many cancers, where the resulting increased nuclear deformability could enhance the ability of cells to transit tight interstitial spaces, thereby promoting metastasis.
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Affiliation(s)
- Patricia M Davidson
- Weill Institute for Cell and Molecular Biology, Cornell University, 526 Campus Road, Ithaca, NY 14853, USA
| | - Jan Lammerding
- Department of Biomedical Engineering/Weill Institute for Cell and Molecular Biology, Cornell University, 526 Campus Road, Ithaca, NY 14853, USA.
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Ciska M, Moreno Díaz de la Espina S. NMCP/LINC proteins: putative lamin analogs in plants? PLANT SIGNALING & BEHAVIOR 2013; 8:e26669. [PMID: 24128696 PMCID: PMC4091594 DOI: 10.4161/psb.26669] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Lamins are the main components of the metazoan lamina, and while the organization of the nuclear lamina of metazoans and plants is similar, there are apparently no genes encoding lamins or most lamin-binding proteins in plants. Thus, the plant lamina is not lamin-based and the proteins that form this structure are still to be characterized. Members of the plant NMCP/LINC/CRWN protein family share the typical tripartite structure of lamins, although the 2 exhibit no sequence similarity. However, given the many similarities between NMCP/LINC/CRWN proteins and lamins (structural organization, position of conserved regions, sub-nuclear distribution, solubility, and pattern of expression), these proteins are good candidates to carry out the functions of lamins in plants. Moreover, functional analysis of NMCP/LINC mutants has revealed their involvement in maintaining nuclear size and shape, another activity fulfilled by lamins. This review summarizes the current understanding of NMCP/LINC proteins and discusses future studies that will be required to demonstrate definitively that these proteins are plant analogs of lamins.
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