151
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Zuela N, Dorfman J, Gruenbaum Y. Global transcriptional changes caused by an EDMD mutation correlate to tissue specific disease phenotypes in C. elegans. Nucleus 2016; 8:60-69. [PMID: 27673727 DOI: 10.1080/19491034.2016.1238999] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
There are numerous heritable diseases associated with mutations in the LMNA gene. Most of these laminopathic diseases, including several muscular dystrophies, are autosomal dominant and have tissue-specific phenotypes. Our previous studies have shown that the globally expressed Emery-Dreifuss muscular dystrophy (EDMD)-linked lamin mutation, L535P, disrupts nuclear mechanical response specifically in muscle nuclei of C. elegans leading to atrophy of the body muscle cells and to reduced motility. Here we used RNA sequencing to analyze the global changes in gene expression caused by the L535P EDMD lamin mutation in order to gain better understanding of disease mechanisms and the correlation between transcription and phenotype. Our results show changes in key genes and biological pathways that can help explain the muscle specific phenotypes. In addition, the differential gene expression between wild-type and L535P mutant animals suggests that the pharynx function in the L535P mutant animals is affected by this lamin mutation. Moreover, these transcriptional changes were then correlated with reduced pharynx activity and abnormal pharynx muscle structure. Understanding disease mechanisms will potentially lead to new therapeutic approaches toward curing EDMD.
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Affiliation(s)
- Noam Zuela
- a Department of Genetics, Institute of Life Sciences, Hebrew University of Jerusalem , Jerusalem , Israel
| | | | - Yosef Gruenbaum
- a Department of Genetics, Institute of Life Sciences, Hebrew University of Jerusalem , Jerusalem , Israel
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152
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Fruleux A, Hawkins RJ. Physical role for the nucleus in cell migration. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:363002. [PMID: 27406341 DOI: 10.1088/0953-8984/28/36/363002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Cell migration is important for the function of many eukaryotic cells. Recently the nucleus has been shown to play an important role in cell motility. After giving an overview of cell motility mechanisms we review what is currently known about the mechanical properties of the nucleus and the connections between it and the cytoskeleton. We also discuss connections to the extracellular matrix and mechanotransduction. We identify key physical roles of the nucleus in cell migration.
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Affiliation(s)
- Antoine Fruleux
- Department of Physics and Astronomy, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH, UK
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153
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Caballero D, Comelles J, Piel M, Voituriez R, Riveline D. Ratchetaxis: Long-Range Directed Cell Migration by Local Cues. Trends Cell Biol 2016; 25:815-827. [PMID: 26615123 DOI: 10.1016/j.tcb.2015.10.009] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 10/07/2015] [Accepted: 10/12/2015] [Indexed: 01/22/2023]
Abstract
Directed cell migration is usually thought to depend on the presence of long-range gradients of either chemoattractants or physical properties such as stiffness or adhesion. However, in vivo, chemical or mechanical gradients have not systematically been observed. Here we review recent in vitro experiments, which show that other types of spatial guidance cues can bias cell motility. Introducing local geometrical or mechanical anisotropy in the cell environment, such as adhesive/topographical microratchets or tilted micropillars, show that local and periodic external cues can direct cell motion. Together with modeling, these experiments suggest that cell motility can be viewed as a stochastic phenomenon, which can be biased by various types of local cues, leading to directional migration.
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Affiliation(s)
- David Caballero
- Laboratory of Cell Physics ISIS/IGBMC, CNRS and University of Strasbourg, Strasbourg, France; Development and Stem Cells Program, IGBMC, CNRS, INSERM and University of Strasbourg, Illkirch, France
| | - Jordi Comelles
- Laboratory of Cell Physics ISIS/IGBMC, CNRS and University of Strasbourg, Strasbourg, France; Development and Stem Cells Program, IGBMC, CNRS, INSERM and University of Strasbourg, Illkirch, France
| | - Matthieu Piel
- Institut Curie, PSL Research University, CNRS, UMR 144, Bio6, F-75005, Paris, France.
| | - Raphaël Voituriez
- Laboratoire de Physique Théorique de la Matière Condensée, CNRS UMR 7600, Université Pierre et Marie Curie, Paris, France; Laboratoire Jean Perrin, CNRS UMR 8237, Université Pierre et Marie Curie, Paris, France.
| | - Daniel Riveline
- Laboratory of Cell Physics ISIS/IGBMC, CNRS and University of Strasbourg, Strasbourg, France; Development and Stem Cells Program, IGBMC, CNRS, INSERM and University of Strasbourg, Illkirch, France.
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154
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Skeletal Muscle Laminopathies: A Review of Clinical and Molecular Features. Cells 2016; 5:cells5030033. [PMID: 27529282 PMCID: PMC5040975 DOI: 10.3390/cells5030033] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 06/01/2016] [Accepted: 06/08/2016] [Indexed: 01/12/2023] Open
Abstract
LMNA-related disorders are caused by mutations in the LMNA gene, which encodes for the nuclear envelope proteins, lamin A and C, via alternative splicing. Laminopathies are associated with a wide range of disease phenotypes, including neuromuscular, cardiac, metabolic disorders and premature aging syndromes. The most frequent diseases associated with mutations in the LMNA gene are characterized by skeletal and cardiac muscle involvement. This review will focus on genetics and clinical features of laminopathies affecting primarily skeletal muscle. Although only symptomatic treatment is available for these patients, many achievements have been made in clarifying the pathogenesis and improving the management of these diseases.
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155
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Malu K, Garhwal R, Pelletier MGH, Gotur D, Halene S, Zwerger M, Yang ZF, Rosmarin AG, Gaines P. Cooperative Activity of GABP with PU.1 or C/EBPε Regulates Lamin B Receptor Gene Expression, Implicating Their Roles in Granulocyte Nuclear Maturation. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2016; 197:910-22. [PMID: 27342846 PMCID: PMC5022553 DOI: 10.4049/jimmunol.1402285] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 05/30/2016] [Indexed: 01/26/2023]
Abstract
Nuclear segmentation is a hallmark feature of mammalian neutrophil differentiation, but the mechanisms that control this process are poorly understood. Gene expression in maturing neutrophils requires combinatorial actions of lineage-restricted and more widely expressed transcriptional regulators. Examples include interactions of the widely expressed ETS transcription factor, GA-binding protein (GABP), with the relatively lineage-restricted E-twenty-six (ETS) factor, PU.1, and with CCAAT enhancer binding proteins, C/EBPα and C/EBPε. Whether such cooperative interactions between these transcription factors also regulate the expression of genes encoding proteins that control nuclear segmentation is unclear. We investigated the roles of ETS and C/EBP family transcription factors in regulating the gene encoding the lamin B receptor (LBR), an inner nuclear membrane protein whose expression is required for neutrophil nuclear segmentation. Although C/EBPε was previously shown to bind the Lbr promoter, surprisingly, we found that neutrophils derived from Cebpe null mice exhibited normal Lbr gene and protein expression. Instead, GABP provided transcriptional activation through the Lbr promoter in the absence of C/EBPε, and activities supported by GABP were greatly enhanced by either C/EBPε or PU.1. Both GABP and PU.1 bound Ets sites in the Lbr promoter in vitro, and in vivo within both early myeloid progenitors and differentiating neutrophils. These findings demonstrate that GABP, PU.1, and C/EBPε cooperate to control transcription of the gene encoding LBR, a nuclear envelope protein that is required for the characteristic lobulated morphology of mature neutrophils.
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Affiliation(s)
- Krishnakumar Malu
- Department of Biological Sciences, Biomedical Engineering and Biotechnology Program, University of Massachusetts, Lowell, MA 01854
| | - Rahul Garhwal
- Department of Biological Sciences, Biomedical Engineering and Biotechnology Program, University of Massachusetts, Lowell, MA 01854
| | - Margery G H Pelletier
- Department of Biological Sciences, Biomedical Engineering and Biotechnology Program, University of Massachusetts, Lowell, MA 01854
| | - Deepali Gotur
- Department of Biological Sciences, Biomedical Engineering and Biotechnology Program, University of Massachusetts, Lowell, MA 01854
| | - Stephanie Halene
- Section of Hematology, Department of Internal Medicine and Yale Comprehensive Cancer Center, Yale University School of Medicine, New Haven, CT 06520
| | - Monika Zwerger
- Department of Biochemistry, University of Zurich, 8057 Zurich, Switzerland; and
| | - Zhong-Fa Yang
- Division of Hematology-Oncology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655
| | - Alan G Rosmarin
- Division of Hematology-Oncology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655
| | - Peter Gaines
- Department of Biological Sciences, Biomedical Engineering and Biotechnology Program, University of Massachusetts, Lowell, MA 01854;
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156
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AIM2 inflammasome is activated by pharmacological disruption of nuclear envelope integrity. Proc Natl Acad Sci U S A 2016; 113:E4671-80. [PMID: 27462105 DOI: 10.1073/pnas.1602419113] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Inflammasomes are critical sensors that convey cellular stress and pathogen presence to the immune system by activating inflammatory caspases and cytokines such as IL-1β. The nature of endogenous stress signals that activate inflammasomes remains unclear. Here we show that an inhibitor of the HIV aspartyl protease, Nelfinavir, triggers inflammasome formation and elicits an IL-1R-dependent inflammation in mice. We found that Nelfinavir impaired the maturation of lamin A, a structural component of the nuclear envelope, thereby promoting the release of DNA in the cytosol. Moreover, deficiency of the cytosolic DNA-sensor AIM2 impaired Nelfinavir-mediated inflammasome activation. These findings identify a pharmacologic activator of inflammasome and demonstrate the role of AIM2 in detecting endogenous DNA release upon perturbation of nuclear envelope integrity.
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157
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Soria-Valles C, Carrero D, Gabau E, Velasco G, Quesada V, Bárcena C, Moens M, Fieggen K, Möhrcken S, Owens M, Puente DA, Asensio Ó, Loeys B, Pérez A, Benoit V, Wuyts W, Lévy N, Hennekam RC, De Sandre-Giovannoli A, López-Otín C. NovelLMNAmutations cause an aggressive atypical neonatal progeria without progerin accumulation. J Med Genet 2016; 53:776-785. [DOI: 10.1136/jmedgenet-2015-103695] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 05/12/2016] [Accepted: 05/26/2016] [Indexed: 11/04/2022]
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158
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McGregor AL, Hsia CR, Lammerding J. Squish and squeeze-the nucleus as a physical barrier during migration in confined environments. Curr Opin Cell Biol 2016; 40:32-40. [PMID: 26895141 PMCID: PMC4887392 DOI: 10.1016/j.ceb.2016.01.011] [Citation(s) in RCA: 146] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 01/23/2016] [Indexed: 01/22/2023]
Abstract
From embryonic development to cancer metastasis, cell migration plays a central role in health and disease. It is increasingly becoming apparent that cells migrating in three-dimensional (3-D) environments exhibit some striking differences compared with their well-established 2-D counterparts. One key finding is the significant role the nucleus plays during 3-D migration: when cells move in confined spaces, the cell body and nucleus must deform to squeeze through available spaces, and the deformability of the large and relatively rigid nucleus can become rate-limiting. In this review, we highlight recent findings regarding the role of nuclear mechanics in 3-D migration, including factors that govern nuclear deformability, and emerging mechanisms by which cells apply cytoskeletal forces to the nucleus to facilitate nuclear translocation. Intriguingly, the 'physical barrier' imposed by the nucleus also impacts cytoplasmic dynamics that affect cell migration and signaling, and changes in nuclear structure resulting from the mechanical forces acting on the nucleus during 3-D migration could further alter cellular function. These findings have broad relevance to the migration of both normal and cancerous cells inside living tissues, and motivate further research into the molecular details by which cells move their nuclei, as well as the consequences of the mechanical stress on the nucleus.
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Affiliation(s)
- Alexandra Lynn McGregor
- Nancy C. and Peter E. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853, USA; Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - Chieh-Ren Hsia
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA; Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - Jan Lammerding
- Nancy C. and Peter E. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853, USA; Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA.
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159
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Barton LJ, Lovander KE, Pinto BS, Geyer PK. Drosophila male and female germline stem cell niches require the nuclear lamina protein Otefin. Dev Biol 2016; 415:75-86. [PMID: 27174470 DOI: 10.1016/j.ydbio.2016.05.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 04/28/2016] [Accepted: 05/02/2016] [Indexed: 12/11/2022]
Abstract
The nuclear lamina is an extensive protein network that underlies the inner nuclear envelope. This network includes the LAP2-emerin-MAN1-domain (LEM-D) protein family, proteins that share an association with the chromatin binding protein Barrier-to-autointegration factor (BAF). Loss of individual LEM-D proteins causes progressive, tissue-restricted diseases, known as laminopathies. Mechanisms associated with laminopathies are not yet understood. Here we present our studies of one of the Drosophila nuclear lamina LEM-D proteins, Otefin (Ote), a homologue of emerin. Previous studies have shown that Ote is autonomously required for the survival of female germline stem cells (GSCs). We demonstrate that Ote is also required for survival of somatic cells in the ovarian niche, with loss of Ote causing a decrease in cap cell number and altered signal transduction. We show germ cell-restricted expression of Ote rescues these defects, revealing a non-autonomous function for Ote in niche maintenance and emphasizing that GSCs contribute to the maintenance of their own niches. Further, we investigate the requirement of Ote in the male fertility. We show that ote mutant males become prematurely sterile as they age. Parallel to observations in females, this sterility is associated with GSC loss and changes in somatic cells of the niche, phenotypes that are largely rescued by germ cell-restricted Ote expression. Taken together, our studies demonstrate that Ote is required autonomously for survival of two stem cell populations, as well as non-autonomously for maintenance of two somatic niches. Finally, our data add to growing evidence that LEM-D proteins have critical roles in stem cell survival and tissue homeostasis.
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Affiliation(s)
- Lacy J Barton
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Kaylee E Lovander
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Belinda S Pinto
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Pamela K Geyer
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA.
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160
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Versaevel M, Riaz M, Corne T, Grevesse T, Lantoine J, Mohammed D, Bruyère C, Alaimo L, De Vos WH, Gabriele S. Probing cytoskeletal pre-stress and nuclear mechanics in endothelial cells with spatiotemporally controlled (de-)adhesion kinetics on micropatterned substrates. Cell Adh Migr 2016; 11:98-109. [PMID: 27111836 DOI: 10.1080/19336918.2016.1182290] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The mechanical properties of living cells reflect their propensity to migrate and respond to external forces. Both cellular and nuclear stiffnesses are strongly influenced by the rigidity of the extracellular matrix (ECM) through reorganization of the cyto- and nucleoskeletal protein connections. Changes in this architectural continuum affect cell mechanics and underlie many pathological conditions. In this context, an accurate and combined quantification of the mechanical properties of both cells and nuclei can contribute to a better understanding of cellular (dys-)function. To address this challenge, we have established a robust method for probing cellular and nuclear deformation during spreading and detachment from micropatterned substrates. We show that (de-)adhesion kinetics of endothelial cells are modulated by substrate stiffness and rely on the actomyosin network. We combined this approach with measurements of cell stiffness by magnetic tweezers to show that relaxation dynamics can be considered as a reliable parameter of cellular pre-stress in adherent cells. During the adhesion stage, large cellular and nuclear deformations occur over a long time span (>60 min). Conversely, nuclear deformation and condensed chromatin are relaxed in a few seconds after detachment. Finally, our results show that accumulation of farnesylated prelamin leads to modifications of the nuclear viscoelastic properties, as reflected by increased nuclear relaxation times. Our method offers an original and non-intrusive way of simultaneously gauging cellular and nuclear mechanics, which can be extended to high-throughput screens of pathological conditions and potential countermeasures.
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Affiliation(s)
- Marie Versaevel
- a University of Mons, Laboratoire Interfaces et Fluides Complexes, Mechanobiology & Soft Matter group, Research Institute for Biosciences , Mons , Belgium
| | - Maryam Riaz
- a University of Mons, Laboratoire Interfaces et Fluides Complexes, Mechanobiology & Soft Matter group, Research Institute for Biosciences , Mons , Belgium
| | - Tobias Corne
- b Laboratory of Cell Biology and Histology, Department Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp , Antwerp , Belgium.,c Cell Systems and Imaging Research Group, Department Molecular Biotechnology, University of Ghent , Ghent , Belgium
| | - Thomas Grevesse
- a University of Mons, Laboratoire Interfaces et Fluides Complexes, Mechanobiology & Soft Matter group, Research Institute for Biosciences , Mons , Belgium
| | - Joséphine Lantoine
- a University of Mons, Laboratoire Interfaces et Fluides Complexes, Mechanobiology & Soft Matter group, Research Institute for Biosciences , Mons , Belgium
| | - Danahe Mohammed
- a University of Mons, Laboratoire Interfaces et Fluides Complexes, Mechanobiology & Soft Matter group, Research Institute for Biosciences , Mons , Belgium
| | - Céline Bruyère
- a University of Mons, Laboratoire Interfaces et Fluides Complexes, Mechanobiology & Soft Matter group, Research Institute for Biosciences , Mons , Belgium
| | - Laura Alaimo
- a University of Mons, Laboratoire Interfaces et Fluides Complexes, Mechanobiology & Soft Matter group, Research Institute for Biosciences , Mons , Belgium
| | - Winnok H De Vos
- b Laboratory of Cell Biology and Histology, Department Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp , Antwerp , Belgium.,c Cell Systems and Imaging Research Group, Department Molecular Biotechnology, University of Ghent , Ghent , Belgium
| | - Sylvain Gabriele
- a University of Mons, Laboratoire Interfaces et Fluides Complexes, Mechanobiology & Soft Matter group, Research Institute for Biosciences , Mons , Belgium
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161
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A model for coordinating nuclear mechanics and membrane remodeling to support nuclear integrity. Curr Opin Cell Biol 2016; 41:9-17. [PMID: 27031045 DOI: 10.1016/j.ceb.2016.03.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 03/10/2016] [Accepted: 03/11/2016] [Indexed: 11/20/2022]
Abstract
A polymer network of intranuclear lamin filaments underlies the nuclear envelope and provides mechanical stability to the nucleus in metazoans. Recent work demonstrates that the expression of A-type lamins scales positively with the stiffness of the cellular environment, thereby coupling nuclear and extracellular mechanics. Using the spectrin-actin network at the erythrocyte plasma membrane as a model, we contemplate how the relative stiffness of the nuclear scaffold impinges on the growing number of interphase-specific nuclear envelope remodeling events, including recently discovered, nuclear envelope-specialized quality control mechanisms. We suggest that a stiffer lamina impedes these remodeling events, necessitating local lamina remodeling and/or concomitant scaling of the efficacy of membrane-remodeling machineries that act at the nuclear envelope.
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162
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Regulation of nuclear shape and size in plants. Curr Opin Cell Biol 2016; 40:114-123. [PMID: 27030912 DOI: 10.1016/j.ceb.2016.03.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 03/03/2016] [Accepted: 03/09/2016] [Indexed: 11/22/2022]
Abstract
Nuclear shape and size changes have long been used by cytopathologists to diagnose, stage, and prognose cancer. However, the underlying causalities and molecular mechanisms are largely unknown. The current eukaryotic tree of life groups eukaryotes into five supergroups, with all organisms between humans and yeast falling into the supergroup Opisthokonta. The emergence of model organisms with strong molecular genetic methodology in the other supergroups has recently facilitated a broader evolutionary approach to pressing biological questions. Here, we review what is known about the control of nuclear shape and size in the Archaeplastidae, the supergroup containing the higher plants. We discuss common themes as well as differences toward a more generalized model of how eukaryotic organisms regulate nuclear morphology.
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163
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Song KH, Lee J, Park H, Kim HM, Park J, Kwon KW, Doh J. Roles of endothelial A-type lamins in migration of T cells on and under endothelial layers. Sci Rep 2016; 6:23412. [PMID: 26996137 PMCID: PMC4800500 DOI: 10.1038/srep23412] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 03/07/2016] [Indexed: 12/30/2022] Open
Abstract
Stiff nuclei in cell-dense microenvironments may serve as distinct biomechanical cues for cell migration, but such a possibility has not been tested experimentally. As a first step addressing this question, we altered nuclear stiffness of endothelial cells (ECs) by reducing the expression of A-type lamins using siRNA, and investigated the migration of T cells on and under EC layers. While most T cells crawling on control EC layers avoided crossing over EC nuclei, a significantly higher fraction of T cells on EC layers with reduced expression of A-type lamins crossed over EC nuclei. This result suggests that stiff EC nuclei underlying T cells may serve as "duro-repulsive" cues to direct T cell migration toward less stiff EC cytoplasm. During subendothelial migration under EC layers with reduced expression of A-type lamins, T cells made prolonged contact and substantially deformed EC nuclei, resulting in reduced speed and directional persistence. This result suggests that EC nuclear stiffness promotes fast and directionally persistent subendothelial migration of T cells by allowing minimum interaction between T cells and EC nuclei.
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Affiliation(s)
- Kwang Hoon Song
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH) San 31, Hyoja-dong, Nam-Gu, Pohang, Gyeongbuk, 790-784, Korea
| | - Jaehyun Lee
- School of Interdisciplinary Bioscience and Bioengineering (I-Bio), Pohang University of Science and Technology (POSTECH) San 31, Hyoja-dong, Nam-Gu, Pohang, Gyeongbuk, 790-784, Korea
| | - HyoungJun Park
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH) San 31, Hyoja-dong, Nam-Gu, Pohang, Gyeongbuk, 790-784, Korea
| | - Hye Mi Kim
- Division of Integrative Bioscience and Biotechnology (IBB), Pohang University of Science and Technology (POSTECH) San 31, Hyoja-dong, Nam-Gu, Pohang, Gyeongbuk, 790-784, Korea
| | - Jeehun Park
- School of Interdisciplinary Bioscience and Bioengineering (I-Bio), Pohang University of Science and Technology (POSTECH) San 31, Hyoja-dong, Nam-Gu, Pohang, Gyeongbuk, 790-784, Korea
| | - Keon Woo Kwon
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH) San 31, Hyoja-dong, Nam-Gu, Pohang, Gyeongbuk, 790-784, Korea
| | - Junsang Doh
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH) San 31, Hyoja-dong, Nam-Gu, Pohang, Gyeongbuk, 790-784, Korea
- School of Interdisciplinary Bioscience and Bioengineering (I-Bio), Pohang University of Science and Technology (POSTECH) San 31, Hyoja-dong, Nam-Gu, Pohang, Gyeongbuk, 790-784, Korea
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164
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Shenoy VB, Wang H, Wang X. A chemo-mechanical free-energy-based approach to model durotaxis and extracellular stiffness-dependent contraction and polarization of cells. Interface Focus 2016; 6:20150067. [PMID: 26855753 DOI: 10.1098/rsfs.2015.0067] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
We propose a chemo-mechanical model based on stress-dependent recruitment of myosin motors to describe how the contractility, polarization and strain in cells vary with the stiffness of their surroundings and their shape. A contractility tensor, which depends on the distribution of myosin motors, is introduced to describe the chemical free energy of the cell due to myosin recruitment. We explicitly include the contributions to the free energy that arise from mechanosensitive signalling pathways (such as the SFX, Rho-Rock and MLCK pathways) through chemo-mechanical coupling parameters. Taking the variations of the total free energy, which consists of the chemical and mechanical components, in accordance with the second law of thermodynamics provides equations for the temporal evolution of the active stress and the contractility tensor. Following this approach, we are able to recover the well-known Hill relation for active stresses, based on the fundamental principles of irreversible thermodynamics rather than phenomenology. We have numerically implemented our free energy-based approach to model spatial distribution of strain and contractility in (i) cells supported by flexible microposts, (ii) cells on two-dimensional substrates, and (iii) cells in three-dimensional matrices. We demonstrate how the polarization of the cells and the orientation of stress fibres can be deduced from the eigenvalues and eigenvectors of the contractility tensor. Our calculations suggest that the chemical free energy of the cell decreases with the stiffness of the extracellular environment as the cytoskeleton polarizes in response to stress-dependent recruitment of molecular motors. The mechanical energy, which includes the strain energy and motor potential energy, however, increases with stiffness, but the overall energy is lower for cells in stiffer environments. This provides a thermodynamic basis for durotaxis, whereby cells preferentially migrate towards stiffer regions of the extracellular environment. Our models also explain, from an energetic perspective, why the shape of the cells can change in response to stiffness of the surroundings. The effect of the stiffness of the nucleus on its shape and the orientation of the stress fibres is also studied for all the above geometries. Along with making testable predictions, we have estimated the magnitudes of the chemo-mechanical coupling parameters for myofibroblasts based on data reported in the literature.
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Affiliation(s)
- Vivek B Shenoy
- Department of Materials Science and Engineering , University of Pennsylvania , Philadelphia, PA 19104 , USA
| | - Hailong Wang
- Department of Materials Science and Engineering , University of Pennsylvania , Philadelphia, PA 19104 , USA
| | - Xiao Wang
- Department of Materials Science and Engineering , University of Pennsylvania , Philadelphia, PA 19104 , USA
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165
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Bronshtein I, Kanter I, Kepten E, Lindner M, Berezin S, Shav-Tal Y, Garini Y. Exploring chromatin organization mechanisms through its dynamic properties. Nucleus 2016; 7:27-33. [PMID: 26854963 PMCID: PMC4916879 DOI: 10.1080/19491034.2016.1139272] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The organization of the genome in the nucleus is believed to be crucial for different cellular functions. It is known that chromosomes fold into distinct territories, but little is known about the mechanisms that maintain these territories. To explore these mechanisms, we used various live-cell imaging methods, including single particle tracking to characterize the diffusion properties of different genomic regions in live cells. Chromatin diffusion is found to be slow and anomalous; in vast contrast, depletion of lamin A protein significantly increases chromatin motion, and the diffusion pattern of chromatin transforms from slow anomalous to fast normal. More than this, depletion of lamin A protein also affects the dynamics of nuclear bodies. Our findings indicate that chromatin motion is mediated by lamin A and we suggest that constrained chromatin mobility allows to maintain chromosome territories. Thus, the discovery of this function of nucleoplasmic lamin A proteins sheds light on the maintenance mechanism of chromosome territories in the interphase nucleus, which ensures the proper function of the genome.
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Affiliation(s)
- Irena Bronshtein
- a Physics Department and Nanotechnology Institute , Bar Ilan University , Ramat Gan , Israel.,b The Mina & Everard Goodman Faculty of Life Sciences and Nanotechnology Institute, Bar Ilan University , Ramat Gan , Israel
| | - Itamar Kanter
- c Faculty of Engineering and Nanotechnology Institute, Bar Ilan University , Ramat Gan , Israel
| | - Eldad Kepten
- d Institut Curie, PSL Research University , CNRS, UMR 3125, INSERM, U 934, Paris , France
| | - Moshe Lindner
- a Physics Department and Nanotechnology Institute , Bar Ilan University , Ramat Gan , Israel
| | - Shirly Berezin
- a Physics Department and Nanotechnology Institute , Bar Ilan University , Ramat Gan , Israel
| | - Yaron Shav-Tal
- b The Mina & Everard Goodman Faculty of Life Sciences and Nanotechnology Institute, Bar Ilan University , Ramat Gan , Israel
| | - Yuval Garini
- a Physics Department and Nanotechnology Institute , Bar Ilan University , Ramat Gan , Israel
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166
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Ramdas NM, Li Q, Shivashankar GV. Regulation of nuclear morphology by actomyosin components and cell geometry. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2016; 2015:342-5. [PMID: 26736269 DOI: 10.1109/embc.2015.7318369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Extracellular microenvironmental signals modulate the coupling between cytoskeleton to nuclear links to regulate gene expression profiles. However the influence of actomyosin assembly on the morphology of the nucleus is not well understood. In this paper, we quantitatively demonstrate the role of cell geometry and specific actomyosin molecular components in their control of nuclear morphology.
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167
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Vuković LD, Jevtić P, Edens LJ, Levy DL. New Insights into Mechanisms and Functions of Nuclear Size Regulation. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2016; 322:1-59. [PMID: 26940517 DOI: 10.1016/bs.ircmb.2015.11.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Nuclear size is generally maintained within a defined range in a given cell type. Changes in cell size that occur during cell growth, development, and differentiation are accompanied by dynamic nuclear size adjustments in order to establish appropriate nuclear-to-cytoplasmic volume relationships. It has long been recognized that aberrations in nuclear size are associated with certain disease states, most notably cancer. Nuclear size and morphology must impact nuclear and cellular functions. Understanding these functional implications requires an understanding of the mechanisms that control nuclear size. In this review, we first provide a general overview of the diverse cellular structures and activities that contribute to nuclear size control, including structural components of the nucleus, effects of DNA amount and chromatin compaction, signaling, and transport pathways that impinge on the nucleus, extranuclear structures, and cell cycle state. We then detail some of the key mechanistic findings about nuclear size regulation that have been gleaned from a variety of model organisms. Lastly, we review studies that have implicated nuclear size in the regulation of cell and nuclear function and speculate on the potential functional significance of nuclear size in chromatin organization, gene expression, nuclear mechanics, and disease. With many fundamental cell biological questions remaining to be answered, the field of nuclear size regulation is still wide open.
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Affiliation(s)
- Lidija D Vuković
- Department of Molecular Biology, University of Wyoming, Laramie, WY, United States of America
| | - Predrag Jevtić
- Department of Molecular Biology, University of Wyoming, Laramie, WY, United States of America
| | - Lisa J Edens
- Department of Molecular Biology, University of Wyoming, Laramie, WY, United States of America
| | - Daniel L Levy
- Department of Molecular Biology, University of Wyoming, Laramie, WY, United States of America.
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168
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Casasola A, Scalzo D, Nandakumar V, Halow J, Recillas-Targa F, Groudine M, Rincón-Arano H. Prelamin A processing, accumulation and distribution in normal cells and laminopathy disorders. Nucleus 2016; 7:84-102. [PMID: 26900797 PMCID: PMC4916894 DOI: 10.1080/19491034.2016.1150397] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 01/28/2016] [Accepted: 01/31/2016] [Indexed: 12/21/2022] Open
Abstract
Lamin A is part of a complex structural meshwork located beneath the nuclear envelope and is involved in both structural support and the regulation of gene expression. Lamin A is initially expressed as prelamin A, which contains an extended carboxyl terminus that undergoes a series of post-translational modifications and subsequent cleavage by the endopeptidase ZMPSTE24 to generate lamin A. To facilitate investigations of the role of this cleavage in normal and disease states, we developed a monoclonal antibody (PL-1C7) that specifically recognizes prelamin A at the intact ZMPSTE24 cleavage site, ensuring prelamin A detection exclusively. Importantly, PL-1C7 can be used to determine prelamin A localization and accumulation in cells where lamin A is highly expressed without the use of exogenous fusion proteins. Our results show that unlike mature lamin A, prelamin A accumulates as discrete and localized foci at the nuclear periphery. Furthermore, whereas treatment with farnesylation inhibitors of cells overexpressing a GFP-prelamin A fusion protein results in the formation of large nucleoplasmic clumps, these aggregates are not observed upon similar treatment of cells expressing endogenous prelamin A or in cells lacking ZMPSTE24 expression and/or activity. Finally, we show that specific laminopathy-associated mutations exhibit both positive and negative effects on prelamin A accumulation, indicating that these mutations affect prelamin A processing efficiency in different manners.
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Affiliation(s)
- Andrea Casasola
- Basic Science Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Instituto Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - David Scalzo
- Basic Science Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Vivek Nandakumar
- Basic Science Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Jessica Halow
- Basic Science Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Félix Recillas-Targa
- Instituto Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Mark Groudine
- Basic Science Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Department of Radiation Oncology, University Washington School of Medicine, Seattle, WA, USA
| | - Héctor Rincón-Arano
- Basic Science Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
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169
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Lyu L, Whitcomb EA, Jiang S, Chang ML, Gu Y, Duncan MK, Cvekl A, Wang WL, Limi S, Reneker LW, Shang F, Du L, Taylor A. Unfolded-protein response-associated stabilization of p27(Cdkn1b) interferes with lens fiber cell denucleation, leading to cataract. FASEB J 2015; 30:1087-95. [PMID: 26590164 DOI: 10.1096/fj.15-278036] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 11/02/2015] [Indexed: 12/21/2022]
Abstract
Failure of lens fiber cell denucleation (LFCD) is associated with congenital cataracts, but the pathobiology awaits elucidation. Recent work has suggested that mechanisms that direct the unidirectional process of LFCD are analogous to the cyclic processes associated with mitosis. We found that lens-specific mutations that elicit an unfolded-protein response (UPR) in vivo accumulate p27(Cdkn1b), show cyclin-dependent kinase (Cdk)-1 inhibition, retain their LFC nuclei, and are cataractous. Although a UPR was not detected in lenses expressing K6W-Ub, they also accumulated p27 and showed failed LFCD. Induction of a UPR in human lens epithelial cells (HLECs) also induced accumulation of p27 associated with decreased levels of S-phase kinase-associated protein (Skp)-2, a ubiquitin ligase that regulates mitosis. These cells also showed decreased lamin A/C phosphorylation and metaphase arrest. The suppression of lamin A/C phosphorylation and metaphase transition induced by the UPR was rescued by knockdown of p27. Taken together, these data indicate that accumulation of p27, whether related to the UPR or not, prevents the phosphorylation of lamin A/C and LFCD in maturing LFCs in vivo, as well as in dividing HLECs. The former leads to cataract and the latter to metaphase arrest. These results suggest that accumulation of p27 is a common mechanism underlying retention of LFC nuclei.
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Affiliation(s)
- Lei Lyu
- *Ministry of Education Key Laboratory of Bio-resource and Eco-environment, College of Life Science, Sichuan University, Sichuan China; Laboratory for Nutrition and Vision Research, Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts, USA; Department of Biological Sciences, University of Delaware, Newark, Delaware, USA; Department of Genetics and Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, New York, USA; and Department of Ophthalmology, School of Medicine, University of Missouri, Columbia, Missouri, USA
| | - Elizabeth A Whitcomb
- *Ministry of Education Key Laboratory of Bio-resource and Eco-environment, College of Life Science, Sichuan University, Sichuan China; Laboratory for Nutrition and Vision Research, Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts, USA; Department of Biological Sciences, University of Delaware, Newark, Delaware, USA; Department of Genetics and Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, New York, USA; and Department of Ophthalmology, School of Medicine, University of Missouri, Columbia, Missouri, USA
| | - Shuhong Jiang
- *Ministry of Education Key Laboratory of Bio-resource and Eco-environment, College of Life Science, Sichuan University, Sichuan China; Laboratory for Nutrition and Vision Research, Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts, USA; Department of Biological Sciences, University of Delaware, Newark, Delaware, USA; Department of Genetics and Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, New York, USA; and Department of Ophthalmology, School of Medicine, University of Missouri, Columbia, Missouri, USA
| | - Min-Lee Chang
- *Ministry of Education Key Laboratory of Bio-resource and Eco-environment, College of Life Science, Sichuan University, Sichuan China; Laboratory for Nutrition and Vision Research, Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts, USA; Department of Biological Sciences, University of Delaware, Newark, Delaware, USA; Department of Genetics and Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, New York, USA; and Department of Ophthalmology, School of Medicine, University of Missouri, Columbia, Missouri, USA
| | - Yumei Gu
- *Ministry of Education Key Laboratory of Bio-resource and Eco-environment, College of Life Science, Sichuan University, Sichuan China; Laboratory for Nutrition and Vision Research, Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts, USA; Department of Biological Sciences, University of Delaware, Newark, Delaware, USA; Department of Genetics and Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, New York, USA; and Department of Ophthalmology, School of Medicine, University of Missouri, Columbia, Missouri, USA
| | - Melinda K Duncan
- *Ministry of Education Key Laboratory of Bio-resource and Eco-environment, College of Life Science, Sichuan University, Sichuan China; Laboratory for Nutrition and Vision Research, Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts, USA; Department of Biological Sciences, University of Delaware, Newark, Delaware, USA; Department of Genetics and Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, New York, USA; and Department of Ophthalmology, School of Medicine, University of Missouri, Columbia, Missouri, USA
| | - Ales Cvekl
- *Ministry of Education Key Laboratory of Bio-resource and Eco-environment, College of Life Science, Sichuan University, Sichuan China; Laboratory for Nutrition and Vision Research, Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts, USA; Department of Biological Sciences, University of Delaware, Newark, Delaware, USA; Department of Genetics and Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, New York, USA; and Department of Ophthalmology, School of Medicine, University of Missouri, Columbia, Missouri, USA
| | - Wei-Lin Wang
- *Ministry of Education Key Laboratory of Bio-resource and Eco-environment, College of Life Science, Sichuan University, Sichuan China; Laboratory for Nutrition and Vision Research, Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts, USA; Department of Biological Sciences, University of Delaware, Newark, Delaware, USA; Department of Genetics and Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, New York, USA; and Department of Ophthalmology, School of Medicine, University of Missouri, Columbia, Missouri, USA
| | - Saima Limi
- *Ministry of Education Key Laboratory of Bio-resource and Eco-environment, College of Life Science, Sichuan University, Sichuan China; Laboratory for Nutrition and Vision Research, Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts, USA; Department of Biological Sciences, University of Delaware, Newark, Delaware, USA; Department of Genetics and Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, New York, USA; and Department of Ophthalmology, School of Medicine, University of Missouri, Columbia, Missouri, USA
| | - Lixing W Reneker
- *Ministry of Education Key Laboratory of Bio-resource and Eco-environment, College of Life Science, Sichuan University, Sichuan China; Laboratory for Nutrition and Vision Research, Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts, USA; Department of Biological Sciences, University of Delaware, Newark, Delaware, USA; Department of Genetics and Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, New York, USA; and Department of Ophthalmology, School of Medicine, University of Missouri, Columbia, Missouri, USA
| | - Fu Shang
- *Ministry of Education Key Laboratory of Bio-resource and Eco-environment, College of Life Science, Sichuan University, Sichuan China; Laboratory for Nutrition and Vision Research, Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts, USA; Department of Biological Sciences, University of Delaware, Newark, Delaware, USA; Department of Genetics and Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, New York, USA; and Department of Ophthalmology, School of Medicine, University of Missouri, Columbia, Missouri, USA
| | - Linfang Du
- *Ministry of Education Key Laboratory of Bio-resource and Eco-environment, College of Life Science, Sichuan University, Sichuan China; Laboratory for Nutrition and Vision Research, Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts, USA; Department of Biological Sciences, University of Delaware, Newark, Delaware, USA; Department of Genetics and Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, New York, USA; and Department of Ophthalmology, School of Medicine, University of Missouri, Columbia, Missouri, USA
| | - Allen Taylor
- *Ministry of Education Key Laboratory of Bio-resource and Eco-environment, College of Life Science, Sichuan University, Sichuan China; Laboratory for Nutrition and Vision Research, Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts, USA; Department of Biological Sciences, University of Delaware, Newark, Delaware, USA; Department of Genetics and Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, New York, USA; and Department of Ophthalmology, School of Medicine, University of Missouri, Columbia, Missouri, USA
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170
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Snider NT, Omary MB. Assays for Posttranslational Modifications of Intermediate Filament Proteins. Methods Enzymol 2015; 568:113-38. [PMID: 26795469 DOI: 10.1016/bs.mie.2015.09.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Intermediate filament (IF) proteins are known to be regulated by a number of posttranslational modifications (PTMs). Phosphorylation is the best-studied IF PTM, whereas ubiquitination, sumoylation, acetylation, glycosylation, ADP-ribosylation, farnesylation, and transamidation are less understood in functional terms but are known to regulate specific IFs under various contexts. The number and diversity of IF PTMs is certain to grow along with rapid advances in proteomic technologies. Therefore, the need for a greater understanding of the implications of PTMs to the structure, organization, and function of the IF cytoskeleton has become more apparent with the increased availability of data from global profiling studies of normal and diseased specimens. This chapter will provide information on established methods for the isolation and monitoring of IF PTMs along with the key reagents that are necessary to carry out these experiments.
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Affiliation(s)
- Natasha T Snider
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina, USA.
| | - M Bishr Omary
- Department of Molecular & Integrative Physiology, Department of Medicine, University of Michigan, Ann Arbor, Michigan, USA; VA Ann Arbor Healthcare System, Ann Arbor, Michigan, USA
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171
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Mitchell MJ, Denais C, Chan MF, Wang Z, Lammerding J, King MR. Lamin A/C deficiency reduces circulating tumor cell resistance to fluid shear stress. Am J Physiol Cell Physiol 2015; 309:C736-46. [PMID: 26447202 DOI: 10.1152/ajpcell.00050.2015] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 09/17/2015] [Indexed: 02/02/2023]
Abstract
Metastasis contributes to over 90% of cancer-related deaths and is initiated when cancer cells detach from the primary tumor, invade the basement membrane, and enter the circulation as circulating tumor cells (CTCs). While metastasis is viewed as an inefficient process with most CTCs dying within the bloodstream, it is evident that some CTCs are capable of resisting hemodynamic shear forces to form secondary tumors in distant tissues. We hypothesized that nuclear lamins A and C (A/C) act as key structural components within CTCs necessary to resist destruction from elevated shear forces of the bloodstream. Herein, we show that, compared with nonmalignant epithelial cells, tumor cells are resistant to elevated fluid shear forces in vitro that mimic those within the bloodstream, as evidenced by significant decreases in cellular apoptosis and necrosis. Knockdown of lamin A/C significantly reduced tumor cell resistance to fluid shear stress, with significantly increased cell death compared with parental tumor cell and nontargeting controls. Interestingly, lamin A/C knockdown increased shear stress-induced tumor cell apoptosis, but did not significantly affect cellular necrosis. These data demonstrate that lamin A/C is an important structural component that enables tumor cell resistance to fluid shear stress-mediated death in the bloodstream, and may thus facilitate survival and hematogenous metastasis of CTCs.
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Affiliation(s)
- Michael J Mitchell
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York; and
| | - Celine Denais
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York; and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York
| | - Maxine F Chan
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York; and
| | - Zhexiao Wang
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York; and
| | - Jan Lammerding
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York; and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York
| | - Michael R King
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York; and
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172
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Jevtić P, Edens LJ, Li X, Nguyen T, Chen P, Levy DL. Concentration-dependent Effects of Nuclear Lamins on Nuclear Size in Xenopus and Mammalian Cells. J Biol Chem 2015; 290:27557-71. [PMID: 26429910 DOI: 10.1074/jbc.m115.673798] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Indexed: 12/17/2022] Open
Abstract
A fundamental question in cell biology concerns the regulation of organelle size. While nuclear size is exquisitely controlled in different cell types, inappropriate nuclear enlargement is used to diagnose and stage cancer. Clarifying the functional significance of nuclear size necessitates an understanding of the mechanisms and proteins that control nuclear size. One structural component implicated in the regulation of nuclear morphology is the nuclear lamina, a meshwork of intermediate lamin filaments that lines the inner nuclear membrane. However, there has not been a systematic investigation of how the level and type of lamin expression influences nuclear size, in part due to difficulties in precisely controlling lamin expression levels in vivo. In this study, we circumvent this limitation by studying nuclei in Xenopus laevis egg and embryo extracts, open biochemical systems that allow for precise manipulation of lamin levels by the addition of recombinant proteins. We find that nuclear growth and size are sensitive to the levels of nuclear lamins, with low and high concentrations increasing and decreasing nuclear size, respectively. Interestingly, each type of lamin that we tested (lamins B1, B2, B3, and A) similarly affected nuclear size whether added alone or in combination, suggesting that total lamin concentration, and not lamin type, is more critical to determining nuclear size. Furthermore, we show that altering lamin levels in vivo, both in Xenopus embryos and mammalian tissue culture cells, also impacts nuclear size. These results have implications for normal development and carcinogenesis where both nuclear size and lamin expression levels change.
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Affiliation(s)
- Predrag Jevtić
- From the Department of Molecular Biology, University of Wyoming, Laramie, Wyoming 82071
| | - Lisa J Edens
- From the Department of Molecular Biology, University of Wyoming, Laramie, Wyoming 82071
| | - Xiaoyang Li
- From the Department of Molecular Biology, University of Wyoming, Laramie, Wyoming 82071
| | - Thang Nguyen
- From the Department of Molecular Biology, University of Wyoming, Laramie, Wyoming 82071
| | - Pan Chen
- From the Department of Molecular Biology, University of Wyoming, Laramie, Wyoming 82071
| | - Daniel L Levy
- From the Department of Molecular Biology, University of Wyoming, Laramie, Wyoming 82071
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173
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Webster BM, Lusk CP. Border Safety: Quality Control at the Nuclear Envelope. Trends Cell Biol 2015; 26:29-39. [PMID: 26437591 DOI: 10.1016/j.tcb.2015.08.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 07/27/2015] [Accepted: 08/07/2015] [Indexed: 10/23/2022]
Abstract
The unique biochemical identity of the nuclear envelope confers its capacity to establish a barrier that protects the nuclear compartment and directly contributes to nuclear function. Recent work uncovered quality control mechanisms employing the endosomal sorting complexes required for transport (ESCRT) machinery and a new arm of endoplasmic reticulum-associated protein degradation (ERAD) to counteract the unfolding, damage, or misassembly of nuclear envelope proteins and ensure the integrity of the nuclear envelope membranes. Moreover, cells have the capacity to recognize and triage defective nuclear pore complexes to prevent their inheritance and preserve the longevity of progeny. These mechanisms serve to highlight the diverse strategies used by cells to maintain nuclear compartmentalization; we suggest they mitigate the progression and severity of diseases associated with nuclear envelope malfunction such as the laminopathies.
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174
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Schellhaus AK, De Magistris P, Antonin W. Nuclear Reformation at the End of Mitosis. J Mol Biol 2015; 428:1962-85. [PMID: 26423234 DOI: 10.1016/j.jmb.2015.09.016] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 09/17/2015] [Accepted: 09/19/2015] [Indexed: 12/17/2022]
Abstract
Cells have developed highly sophisticated ways to accurately pass on their genetic information to the daughter cells. In animal cells, which undergo open mitosis, the nuclear envelope breaks down at the beginning of mitosis and the chromatin massively condenses to be captured and segregated by the mitotic spindle. These events have to be reverted in order to allow the reformation of a nucleus competent for DNA transcription and replication, as well as all other nuclear processes occurring in interphase. Here, we summarize our current knowledge of how, in animal cells, the highly compacted mitotic chromosomes are decondensed at the end of mitosis and how a nuclear envelope, including functional nuclear pore complexes, reassembles around these decondensing chromosomes.
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Affiliation(s)
| | - Paola De Magistris
- Friedrich Miescher Laboratory of the Max Planck Society, Spemannstrasse 39, 72076 Tübingen, Germany
| | - Wolfram Antonin
- Friedrich Miescher Laboratory of the Max Planck Society, Spemannstrasse 39, 72076 Tübingen, Germany.
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175
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The Cardiomyopathy Lamin A/C D192G Mutation Disrupts Whole-Cell Biomechanics in Cardiomyocytes as Measured by Atomic Force Microscopy Loading-Unloading Curve Analysis. Sci Rep 2015; 5:13388. [PMID: 26323789 PMCID: PMC4555041 DOI: 10.1038/srep13388] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 07/23/2015] [Indexed: 12/30/2022] Open
Abstract
Atomic force microscopy (AFM) cell loading/unloading curves were used to provide comprehensive insights into biomechanical behavior of cardiomyocytes carrying the lamin A/C (LMNA) D192G mutation known to cause defective nuclear wall, myopathy and severe cardiomyopathy. Our results suggested that the LMNA D192G mutation increased maximum nuclear deformation load, nuclear stiffness and fragility as compared to controls. Furthermore, there seems to be a connection between this lamin nuclear mutation and cell adhesion behavior since LMNA D192G cardiomyocytes displayed loss of AFM probe-to-cell membrane adhesion. We believe that this loss of adhesion involves the cytoskeletal architecture since our microscopic analyses highlighted that mutant LMNA may also lead to a morphological alteration in the cytoskeleton. Furthermore, chemical disruption of the actin cytoskeleton by cytochalasin D in control cardiomyocytes mirrored the alterations in the mechanical properties seen in mutant cells, suggesting a defect in the connection between the nucleoskeleton, cytoskeleton and cell adhesion molecules in cells expressing the mutant protein. These data add to our understanding of potential mechanisms responsible for this fatal cardiomyopathy, and show that the biomechanical effects of mutant lamin extend beyond nuclear mechanics to include interference of whole-cell biomechanical properties.
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176
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Different surface sensing of the cell body and nucleus in healthy primary cells and in a cancerous cell line on nanogrooves. Biointerphases 2015; 10:031004. [DOI: 10.1116/1.4927556] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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177
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Krause M, Wolf K. Cancer cell migration in 3D tissue: negotiating space by proteolysis and nuclear deformability. Cell Adh Migr 2015; 9:357-66. [PMID: 26301444 DOI: 10.1080/19336918.2015.1061173] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Efficient tumor cell invasion into the surrounding desmoplastic stroma is a hallmark of cancer progression and involves the navigation through available small tissue spaces existent within the dense stromal network. Such navigation includes the reciprocal adaptation of the moving tumor cell, including the nucleus as largest and stiffest organelle, to pre-existent or de-novo generated extracellular matrix (ECM) gaps, pores and trails within stromal compartments. Within the context of migration, we briefly summarize physiological and tumor-related changes in ECM geometries as well as tissue proteolysis. We then focus on mechanisms that ensure the successful translocation of a nucleus through a confining pore by cytoskeleton-mediated coupling, as well as regulators of cell and nuclear deformability such as chromatin organization and nuclear lamina expression. In summary, understanding dynamic nuclear mechanics during migration in response to confined space will add to a better conceptual appreciation of cancer invasion and progression.
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Affiliation(s)
- Marina Krause
- a Department of Cell Biology ; Radboud University Medical Center ; Nijmegen , The Netherlands
| | - Katarina Wolf
- a Department of Cell Biology ; Radboud University Medical Center ; Nijmegen , The Netherlands
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178
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Zhang Z, Li C, Wu F, Ma R, Luan J, Yang F, Liu W, Wang L, Zhang S, Liu Y, Gu J, Hua W, Fan M, Peng H, Meng X, Song N, Bi X, Gu C, Zhang Z, Huang Q, Chen L, Xiang L, Xu J, Zheng Z, Jiang Z. Genomic variations of the mevalonate pathway in porokeratosis. eLife 2015. [PMID: 26202976 PMCID: PMC4511816 DOI: 10.7554/elife.06322] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Porokeratosis (PK) is a heterogeneous group of keratinization disorders. No causal genes except MVK have been identified, even though the disease was linked to several genomic loci. Here, we performed massively parallel sequencing and exonic CNV screening of 12 isoprenoid genes in 134 index PK patients (61 familial and 73 sporadic) and identified causal mutations in three novel genes (PMVK, MVD, and FDPS) in addition to MVK in the mevalonate pathway. Allelic expression imbalance (AEI) assays were performed in 13 lesional tissues. At least one mutation in one of the four genes in the mevalonate pathway was found in 60 (98%) familial and 53 (73%) sporadic patients, which suggests that isoprenoid biosynthesis via the mevalonate pathway may play a role in the pathogenesis of PK. Significantly reduced expression of the wild allele was common in lesional tissues due to gene conversion or some other unknown mechanism. A G-to-A RNA editing was observed in one lesional tissue without AEI. In addition, we observed correlations between the mutations in the four mevalonate pathway genes and clinical manifestations in the PK patients, which might support a new and simplified classification of PK under the guidance of genetic testing. DOI:http://dx.doi.org/10.7554/eLife.06322.001 Porokeratosis refers to a group of around twenty skin conditions that involve a build-up of a protein called keratin in skin cells. Keratin forms the tough fibres that give strength to hair and nails, and people suffering from porokeratosis develop hardened skin lesions. Porokeratosis is an uncommon condition; most cases are inherited and have been linked to exposure to ultraviolet light and having a weakened immune system. Mutations in one gene called MVK are known to cause two forms of the disorder, but it is suspected that other genetic causes of porokeratosis will also be identified. The MVK gene encodes an enzyme that is involved in making chemicals called isoprenoids. This large and diverse class of chemicals provides the building blocks for making many other important molecules in all living species. Zhang, Li et al. have now analysed genetic material from 134 different porokeratosis patients to search for mutations in other genes involved in the production of isoprenoids. The patients examined include 61 people with a family history of the disorder, and 73 cases in which the condition seems to be a one-off occurrence. This search identified mutations in three additional genes (called PMVK, MVD and FDPS) that are all linked to porokeratosis. Further analysis of these three genes and MVK revealed that about half of the patients with mutations in the MVK gene developed large lesions (that were over 5 centimetres in diameter). However, those with mutations in the other three genes did not develop such large lesions. Mutations in some of the newly identified genes were instead linked to porokeratosis affecting specific areas of the body; for example, PMVK and MVD mutations are linked to porokeratosis localized to the genitals and around the eyes, respectively. This means that, in the future, doctors might be able to simplify the diagnosis of the different varieties of porokeratosis based on information gained via genetic tests. DOI:http://dx.doi.org/10.7554/eLife.06322.002
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Affiliation(s)
- Zhenghua Zhang
- Department of Dermatology, Huashan Hospital, Shanghai Medical College of Fudan University, Shanghai, China
| | - Caihua Li
- School of Life Sciences, Fudan University, Shanghai, China
| | - Fei Wu
- Shanghai Dermatology Hospital, Shanghai, China
| | - Ruixiao Ma
- Genesky Biotechnologies Inc, Shanghai, China
| | - Jing Luan
- Department of Dermatology, Huashan Hospital, Shanghai Medical College of Fudan University, Shanghai, China
| | - Feng Yang
- Genesky Biotechnologies Inc, Shanghai, China
| | - Weida Liu
- Institute of Dermatology, Chinese Academy of Medical Sciences, Nanjing, China
| | - Li Wang
- Genesky Biotechnologies Inc, Shanghai, China
| | - Shoumin Zhang
- Department of Dermatology, Henan Provincial People's Hospital, Zhengzhou, China
| | - Yan Liu
- Genesky Biotechnologies Inc, Shanghai, China
| | - Jun Gu
- Department of Dermatology, Changhai Hospital, Second Military Medical University, Shanghai, China
| | - Wenlian Hua
- Genesky Biotechnologies Inc, Shanghai, China
| | - Min Fan
- Shenzhen Ruimin Dermatology Hospital, Shenzhen, China
| | - Hua Peng
- Genesky Biotechnologies Inc, Shanghai, China
| | - Xuemei Meng
- Department of Dermatology, Central Hospital of China National Petroleum Corp, Langfang, China
| | - Ningjing Song
- Department of Dermatology, Tongji Hospital, Shanghai Jiaotong University, Shanghai, China
| | - Xinling Bi
- Department of Dermatology, Changhai Hospital, Second Military Medical University, Shanghai, China
| | - Chaoying Gu
- Department of Dermatology, Huashan Hospital, Shanghai Medical College of Fudan University, Shanghai, China
| | - Zhen Zhang
- Department of Dermatology, Huashan Hospital, Shanghai Medical College of Fudan University, Shanghai, China
| | - Qiong Huang
- Department of Dermatology, Huashan Hospital, Shanghai Medical College of Fudan University, Shanghai, China
| | - Lianjun Chen
- Department of Dermatology, Huashan Hospital, Shanghai Medical College of Fudan University, Shanghai, China
| | - Leihong Xiang
- Department of Dermatology, Huashan Hospital, Shanghai Medical College of Fudan University, Shanghai, China
| | - Jinhua Xu
- Department of Dermatology, Huashan Hospital, Shanghai Medical College of Fudan University, Shanghai, China
| | - Zhizhong Zheng
- Department of Dermatology, Huashan Hospital, Shanghai Medical College of Fudan University, Shanghai, China
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179
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Scharner J, Figeac N, Ellis JA, Zammit PS. Ameliorating pathogenesis by removing an exon containing a missense mutation: a potential exon-skipping therapy for laminopathies. Gene Ther 2015; 22:503-15. [PMID: 25832542 DOI: 10.1038/gt.2015.8] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 12/18/2014] [Accepted: 12/30/2014] [Indexed: 01/07/2023]
Abstract
Exon skipping, as a therapy to restore a reading frame or switch protein isoforms, is under clinical trial. We hypothesised that removing an in-frame exon containing a mutation could also improve pathogenic phenotypes. Our model is laminopathies: incurable tissue-specific degenerative diseases associated with LMNA mutations. LMNA encodes A-type lamins, that together with B-type lamins, form the nuclear lamina. Lamins contain an alpha-helical central rod domain composed of multiple heptad repeats. Eliminating LMNA exon 3 or 5 removes six heptad repeats, so shortens, but should not otherwise significantly alter, the alpha-helix. Human Lamin A or Lamin C with a deletion corresponding to amino acids encoded by exon 5 (Lamin A/C-Δ5) localised normally in murine lmna-null cells, rescuing both nuclear shape and endogenous Lamin B1/emerin distribution. However, Lamin A carrying pathogenic mutations in exon 3 or 5, or Lamin A/C-Δ3, did not. Furthermore, Lamin A/C-Δ5 was not deleterious to wild-type cells, unlike the other Lamin A mutants including Lamin A/C-Δ3. Thus Lamin A/C-Δ5 function as effectively as wild-type Lamin A/C and better than mutant versions. Antisense oligonucleotides skipped LMNA exon 5 in human cells, demonstrating the possibility of treating certain laminopathies with this approach. This proof-of-concept is the first to report the therapeutic potential of exon skipping for diseases arising from missense mutations.
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Affiliation(s)
- J Scharner
- Randall Division of Cell and Molecular Biophysics, King's College London, London, UK
| | - N Figeac
- Randall Division of Cell and Molecular Biophysics, King's College London, London, UK
| | - J A Ellis
- Randall Division of Cell and Molecular Biophysics, King's College London, London, UK
| | - P S Zammit
- Randall Division of Cell and Molecular Biophysics, King's College London, London, UK
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180
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Malashicheva A, Bogdanova M, Zabirnyk A, Smolina N, Ignatieva E, Freilikhman O, Fedorov A, Dmitrieva R, Sjöberg G, Sejersen T, Kostareva A. Various lamin A/C mutations alter expression profile of mesenchymal stem cells in mutation specific manner. Mol Genet Metab 2015; 115:118-27. [PMID: 25982065 DOI: 10.1016/j.ymgme.2015.04.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 04/27/2015] [Accepted: 04/28/2015] [Indexed: 12/31/2022]
Abstract
Various mutations in LMNA gene, encoding for nuclear lamin A/C protein, lead to laminopathies and contribute to over ten human disorders, mostly affecting tissues of mesenchymal origin such as fat tissue, muscle tissue, and bones. Recently it was demonstrated that lamins not only play a structural role providing communication between extra-nuclear structures and components of cell nucleus but also control cell fate and differentiation. In our study we assessed the effect of various LMNA mutations on the expression profile of mesenchymal multipotent stem cells (MMSC) during adipogenic and osteogenic differentiation. We used lentiviral approach to modify human MMSC with LMNA-constructs bearing mutations associated with different laminopathies--G465D, R482L, G232E, R527C, and R471C. The impact of various mutations on MMSC differentiation properties and expression profile was assessed by colony-forming unit analysis, histological staining, expression of the key differentiation markers promoting adipogenesis and osteogenesis followed by the analysis of the whole set of genes involved in lineage-specific differentiation using PCR expression arrays. We demonstrate that various LMNA mutations influence the differentiation efficacy of MMSC in mutation-specific manner. Each LMNA mutation promotes a unique expression pattern of genes involved in a lineage-specific differentiation and this pattern is shared by the phenotype-specific mutations.
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Affiliation(s)
- Anna Malashicheva
- Almazov Federal Medical Research Centre, St. Petersburg, Russia; St. Petersburg State University, St. Petersburg, Russia; ITMO University, Institute of translational Medicine, St. Petersburg, Russia
| | - Maria Bogdanova
- Almazov Federal Medical Research Centre, St. Petersburg, Russia; St. Petersburg State University, St. Petersburg, Russia
| | | | - Natalia Smolina
- Almazov Federal Medical Research Centre, St. Petersburg, Russia; Department of Woman and Child Health, Centre for Molecular Medicine, Karolinska Institute, Stockholm, Sweden
| | - Elena Ignatieva
- Almazov Federal Medical Research Centre, St. Petersburg, Russia
| | | | - Anton Fedorov
- Almazov Federal Medical Research Centre, St. Petersburg, Russia
| | | | - Gunnar Sjöberg
- Department of Woman and Child Health, Centre for Molecular Medicine, Karolinska Institute, Stockholm, Sweden
| | - Thomas Sejersen
- Department of Woman and Child Health, Centre for Molecular Medicine, Karolinska Institute, Stockholm, Sweden
| | - Anna Kostareva
- Almazov Federal Medical Research Centre, St. Petersburg, Russia; Department of Woman and Child Health, Centre for Molecular Medicine, Karolinska Institute, Stockholm, Sweden; ITMO University, Institute of translational Medicine, St. Petersburg, Russia.
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181
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Polyphyly of nuclear lamin genes indicates an early eukaryotic origin of the metazoan-type intermediate filament proteins. Sci Rep 2015; 5:10652. [PMID: 26024016 PMCID: PMC4448529 DOI: 10.1038/srep10652] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 04/20/2015] [Indexed: 12/24/2022] Open
Abstract
The nuclear lamina is a protein meshwork associated with the inner side of the nuclear envelope contributing structural, signalling and regulatory functions. Here, I report on the evolution of an important component of the lamina, the lamin intermediate filament proteins, across the eukaryotic tree of life. The lamins show a variety of protein domain and sequence motif architectures beyond the classical α-helical rod, nuclear localisation signal, immunoglobulin domain and CaaX motif organisation, suggesting extension and adaptation of functions in many species. I identified lamin genes not only in metazoa and Amoebozoa as previously described, but also in other opisthokonts including Ichthyosporea and choanoflagellates, in oomycetes, a sub-family of Stramenopiles, and in Rhizaria, implying that they must have been present very early in eukaryotic evolution if not even the last common ancestor of all extant eukaryotes. These data considerably extend the current perception of lamin evolution and have important implications with regard to the evolution of the nuclear envelope.
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182
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Myopathic lamin mutations cause reductive stress and activate the nrf2/keap-1 pathway. PLoS Genet 2015; 11:e1005231. [PMID: 25996830 PMCID: PMC4440730 DOI: 10.1371/journal.pgen.1005231] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 04/20/2015] [Indexed: 12/29/2022] Open
Abstract
Mutations in the human LMNA gene cause muscular dystrophy by mechanisms that are incompletely understood. The LMNA gene encodes A-type lamins, intermediate filaments that form a network underlying the inner nuclear membrane, providing structural support for the nucleus and organizing the genome. To better understand the pathogenesis caused by mutant lamins, we performed a structural and functional analysis on LMNA missense mutations identified in muscular dystrophy patients. These mutations perturb the tertiary structure of the conserved A-type lamin Ig-fold domain. To identify the effects of these structural perturbations on lamin function, we modeled these mutations in Drosophila Lamin C and expressed the mutant lamins in muscle. We found that the structural perturbations had minimal dominant effects on nuclear stiffness, suggesting that the muscle pathology was not accompanied by major structural disruption of the peripheral nuclear lamina. However, subtle alterations in the lamina network and subnuclear reorganization of lamins remain possible. Affected muscles had cytoplasmic aggregation of lamins and additional nuclear envelope proteins. Transcription profiling revealed upregulation of many Nrf2 target genes. Nrf2 is normally sequestered in the cytoplasm by Keap-1. Under oxidative stress Nrf2 dissociates from Keap-1, translocates into the nucleus, and activates gene expression. Unexpectedly, biochemical analyses revealed high levels of reducing agents, indicative of reductive stress. The accumulation of cytoplasmic lamin aggregates correlated with elevated levels of the autophagy adaptor p62/SQSTM1, which also binds Keap-1, abrogating Nrf2 cytoplasmic sequestration, allowing Nrf2 nuclear translocation and target gene activation. Elevated p62/SQSTM1 and nuclear enrichment of Nrf2 were identified in muscle biopsies from the corresponding muscular dystrophy patients, validating the disease relevance of our Drosophila model. Thus, novel connections were made between mutant lamins and the Nrf2 signaling pathway, suggesting new avenues of therapeutic intervention that include regulation of protein folding and metabolism, as well as maintenance of redox homoeostasis.
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183
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Kwan R, Looi KS, Omary MB. Absence of keratins 8 and 18 in rodent epithelial cell lines associates with keratin gene mutation and DNA methylation: Cell line selective effects on cell invasion. Exp Cell Res 2015; 335:12-22. [PMID: 25882495 DOI: 10.1016/j.yexcr.2015.04.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 03/02/2015] [Accepted: 04/05/2015] [Indexed: 02/07/2023]
Abstract
Epithelial-mesenchymal transition (EMT) in carcinoma is associated with dramatic up-regulation of vimentin and down-regulation of the simple-type keratins 8 and 18 (K8/K18), but the mechanisms of these changes are poorly understood. We demonstrate that two commonly-studied murine (CT26) and rat (IEC-6) intestinal cell lines have negligible K8/K18 but high vimentin protein expression. Proteasome inhibition led to a limited increase in K18 but not K8 stabilization, thereby indicating that K8/K18 absence is not due, in large part, to increased protein turnover. CT26 and IEC-6 cells had <10% of normal K8/K18 mRNA and exhibited decreased mRNA stability, with K8 mRNA levels being higher in IEC-6 versus CT26 and K18 being higher in CT26 versus IEC-6 cells. Keratin gene sequencing showed that KRT8 in CT26 cells had a 21-nucleotide deletion while K18 in IEC-6 cells had a 9-amino acid in-frame insertion. Furthermore, the KRT8 promoter in CT26 and the KRT18 promoter in IEC-6 are hypermethylated. Inhibition of DNA methylation using 5-azacytidine increased K8 or K18 in some but all the tested rodent epithelial cell lines. Restoring K8 and K18 by lentiviral transduction reduced CT26 but not IEC-6 cell matrigel invasion. K8/K18 re-introduction also decreased E-cadherin expression in IEC-6 but not CT26 cells, suggesting that the effect of keratin expression on epithelial to mesenchymal transition is cell-line dependent. Therefore, some commonly utilized rodent epithelial cell lines, unexpectedly, manifest barely detectable keratin expression but have high levels of vimentin. In the CT26 and IEC-6 intestinal cell lines, keratin expression correlates with keratin gene insertion or deletion and with promoter methylation, which likely suppress keratin transcription and mRNA or protein stability.
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Affiliation(s)
- Raymond Kwan
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, 7744 Medical Science Building II, 1301 E. Catherine, Ann Arbor, MI 48109
| | - Kok Sun Looi
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, 7744 Medical Science Building II, 1301 E. Catherine, Ann Arbor, MI 48109
| | - M Bishr Omary
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, 7744 Medical Science Building II, 1301 E. Catherine, Ann Arbor, MI 48109.,Ann Arbor Health System VA Medical Center
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184
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Barton LJ, Soshnev AA, Geyer PK. Networking in the nucleus: a spotlight on LEM-domain proteins. Curr Opin Cell Biol 2015; 34:1-8. [PMID: 25863918 DOI: 10.1016/j.ceb.2015.03.005] [Citation(s) in RCA: 137] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 03/23/2015] [Accepted: 03/25/2015] [Indexed: 11/29/2022]
Abstract
Proteins resident in the inner nuclear membrane and underlying nuclear lamina form a network that regulates nuclear functions. This review highlights a prominent family of nuclear lamina proteins that carries the LAP2-emerin-MAN1-domain (LEM-D). LEM-D proteins share an ability to bind lamins and tether repressive chromatin at the nuclear periphery. The importance of this family is underscored by findings that loss of individual LEM-D proteins causes progressive, tissue-restricted diseases, known as laminopathies. Diverse functions of LEM-D proteins are linked to interactions with unique and overlapping partners including signal transduction effectors, transcription factors and architectural proteins. Recent investigations suggest that LEM-D proteins form hubs within the nuclear lamina that integrate external signals important for tissue homeostasis and maintenance of progenitor cell populations.
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Affiliation(s)
- Lacy J Barton
- Department of Biochemistry, University of Iowa, College of Medicine, Iowa City, IA 52242, USA; Skirball Institute, Department of Cell Biology, NYU School of Medicine, NYU Langone Medical Center, New York, NY 10016, USA
| | - Alexey A Soshnev
- Laboratory of Chromatin Biology and Epigenetics, The Rockefeller University, New York, NY, 10065, USA
| | - Pamela K Geyer
- Department of Biochemistry, University of Iowa, College of Medicine, Iowa City, IA 52242, USA.
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185
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Clinical and functional characterization of a novel mutation in lamin a/c gene in a multigenerational family with arrhythmogenic cardiac laminopathy. PLoS One 2015; 10:e0121723. [PMID: 25837155 PMCID: PMC4383583 DOI: 10.1371/journal.pone.0121723] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 02/03/2015] [Indexed: 11/19/2022] Open
Abstract
Mutations in the lamin A/C gene (LMNA) were associated with dilated cardiomyopathy (DCM) and, recently, were related to severe forms of arrhythmogenic right ventricular cardiomyopathy (ARVC). Both genetic and phenotypic overlap between DCM and ARVC was observed; molecular pathomechanisms leading to the cardiac phenotypes caused by LMNA mutations are not yet fully elucidated. This study involved a large Italian family, spanning 4 generations, with arrhythmogenic cardiomyopathy of different phenotypes, including ARVC, DCM, system conduction defects, ventricular arrhythmias, and sudden cardiac death. Mutation screening of LMNA and ARVC-related genes PKP2, DSP, DSG2, DSC2, JUP, and CTNNA3 was performed. We identified a novel heterozygous mutation (c.418_438dup) in LMNA gene exon 2, occurring in a highly conserved protein domain across several species. This newly identified variant was not found in 250 ethnically-matched control subjects. Genotype-phenotype correlation studies suggested a co-segregation of the LMNA mutation with the disease phenotype and an incomplete and age-related penetrance. Based on clinical, pedigree, and molecular genetic data, this mutation was considered likely disease-causing. To clarify its potential pathophysiologic impact, functional characterization of this LMNA mutant was performed in cultured cardiomyocytes expressing EGFP-tagged wild-type and mutated LMNA constructs, and indicated an increased nuclear envelope fragility, leading to stress-induced apoptosis as the main pathogenetic mechanism. This study further expands the role of the LMNA gene in the pathogenesis of cardiac laminopathies, suggesting that LMNA should be included in mutation screening of patients with suspected arrhythmogenic cardiomyopathy, particularly when they have ECG evidence for conduction defects. The combination of clinical, genetic, and functional data contribute insights into the pathogenesis of this form of life-threatening arrhythmogenic cardiac laminopathy.
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186
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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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187
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Petillo R, D'Ambrosio P, Torella A, Taglia A, Picillo E, Testori A, Ergoli M, Nigro G, Piluso G, Nigro V, Politano L. Novel mutations in LMNA A/C gene and associated phenotypes. ACTA MYOLOGICA : MYOPATHIES AND CARDIOMYOPATHIES : OFFICIAL JOURNAL OF THE MEDITERRANEAN SOCIETY OF MYOLOGY 2015; 34:116-9. [PMID: 27199538 PMCID: PMC4859074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Mutations in the lamin A/C gene (LMNA) have been associated with several phenotypes ranging from systemic to prevalent of muscle, heart, skin, nerve etc. More recently they have been associated with dilated cardiomyopathy (DCM) and severe forms of arrhythmogenic right ventricular cardiomyopathy (ARVC). We report four novel mutations - 3 missense and 1 deletion - in 4 unrelated patients showing different phenotypes, ranging from the early onset congenital form of laminopathy to classical LGMD phenotype, to LGMD and heart involvement. All these newly identified variants were not found in 300 ethnicallymatched control subjects. The variant c.103-105del CTG was described post-mortem in a young patient with congenital muscular dystrophy who presented at the age of 9 a first degree A-V block and subsequently several episodes of supraventricular parossystic tachycardia. Two patients presented as onset symptom lower limbs muscle weakness, and developed heart conduction defects requiring pacemaker implantation at the age of 26 and 38 years, respectively. One of them who carried the mutation c.1339G>C died at the age of 40 by intractable heart failure; the second one carrying the mutation 265C>T died at the age of 30, for a trmboembolic event. A classical LGMD phenotype without heart involvement was observed in the patient with the mutation 1579C>T, who died at the age of 68 years for respiratory insufficiency.
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Affiliation(s)
- Roberta Petillo
- Cardiomyology and Medical Genetics, Department of Experimental Medicine
| | - Paola D'Ambrosio
- Cardiomyology and Medical Genetics, Department of Experimental Medicine
| | - Annalaura Torella
- Laboratory of Medical Genetics, Department of Biochemistry, Biophysics and General Pathology
| | - Antonella Taglia
- Cardiomyology and Medical Genetics, Department of Experimental Medicine
| | - Esther Picillo
- Cardiomyology and Medical Genetics, Department of Experimental Medicine
| | | | - Manuela Ergoli
- Cardiomyology and Medical Genetics, Department of Experimental Medicine
| | - Gerardo Nigro
- Arrhythmologic Unit, Department of Cardiothoracic Sciences, Second University of Naples, Italy
| | - Giulio Piluso
- Laboratory of Medical Genetics, Department of Biochemistry, Biophysics and General Pathology
| | - Vincenzo Nigro
- Laboratory of Medical Genetics, Department of Biochemistry, Biophysics and General Pathology
| | - Luisa Politano
- Cardiomyology and Medical Genetics, Department of Experimental Medicine;,Address for correspondence: Prof. Luisa Politano, Cardiomyology and Medical Genetics, Department of Experimental Medicine,
I Policlinico, piazza Miraglia, 80138 Naples, Italy. E-mail:
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188
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George CM, Bozler J, Nguyen HQ, Bosco G. Condensins are Required for Maintenance of Nuclear Architecture. Cells 2014; 3:865-82. [PMID: 25153163 PMCID: PMC4197639 DOI: 10.3390/cells3030865] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2014] [Revised: 06/20/2014] [Accepted: 08/11/2014] [Indexed: 12/14/2022] Open
Abstract
The 3-dimensional spatial organization of eukaryotic genomes is important for regulation of gene expression as well as DNA damage repair. It has been proposed that one basic biophysical property of all nuclei is that interphase chromatin must be kept in a condensed prestressed state in order to prevent entropic pressure of the DNA polymer from expanding and disrupting the nuclear envelope. Although many factors can contribute to specific organizational states to compact chromatin, the mechanisms through which such interphase chromatin compaction is maintained are not clearly understood. Condensin proteins are known to exert compaction forces on chromosomes in anticipation of mitosis, but it is not known whether condensins also function to maintain interphase prestressed chromatin states. Here we show that RNAi depletion of the N-CAP-H2, N-CAP-D3 and SMC2 subunits of human condensin II leads to dramatic disruption of nuclear architecture and nuclear size. This is consistent with the idea that condensin mediated chromatin compaction contributes significantly to the prestressed condensed state of the interphase nucleus, and when such compaction forces are disrupted nuclear size and shape change due to chromatin expansion.
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Affiliation(s)
- Carolyn M George
- Department of Genetics, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA.
| | - Julianna Bozler
- Department of Genetics, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA.
| | - Huy Q Nguyen
- Department of Genetics, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA.
| | - Giovanni Bosco
- Department of Genetics, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA.
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189
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Swift J, Discher DE. The nuclear lamina is mechano-responsive to ECM elasticity in mature tissue. J Cell Sci 2014; 127:3005-15. [PMID: 24963133 DOI: 10.1242/jcs.149203] [Citation(s) in RCA: 144] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
How cells respond to physical cues in order to meet and withstand the physical demands of their immediate surroundings has been of great interest for many years, with current research efforts focused on mechanisms that transduce signals into gene expression. Pathways that mechano-regulate the entry of transcription factors into the cell nucleus are emerging, and our most recent studies show that the mechanical properties of the nucleus itself are actively controlled in response to the elasticity of the extracellular matrix (ECM) in both mature and developing tissue. In this Commentary, we review the mechano-responsive properties of nuclei as determined by the intermediate filament lamin proteins that line the inside of the nuclear envelope and that also impact upon transcription factor entry and broader epigenetic mechanisms. We summarize the signaling pathways that regulate lamin levels and cell-fate decisions in response to a combination of ECM mechanics and molecular cues. We will also discuss recent work that highlights the importance of nuclear mechanics in niche anchorage and cell motility during development, hematopoietic differentiation and cancer metastasis, as well as emphasizing a role for nuclear mechanics in protecting chromatin from stress-induced damage.
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Affiliation(s)
- Joe Swift
- Molecular and Cell Biophysics Lab, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Dennis E Discher
- Molecular and Cell Biophysics Lab, University of Pennsylvania, Philadelphia, PA 19104, USA
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Nuclear deformability constitutes a rate-limiting step during cell migration in 3-D environments. Cell Mol Bioeng 2014; 7:293-306. [PMID: 25436017 DOI: 10.1007/s12195-014-0342-y] [Citation(s) in RCA: 200] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Cell motility plays a critical role in many physiological and pathological settings, ranging from wound healing to cancer metastasis. While cell migration on 2-dimensional (2-D) substrates has been studied for decades, the physical challenges cells face when moving in 3-D environments are only now emerging. In particular, the cell nucleus, which occupies a large fraction of the cell volume and is normally substantially stiffer than the surrounding cytoplasm, may impose a major obstacle when cells encounter narrow constrictions in the interstitial space, the extracellular matrix, or small capillaries. Using novel microfluidic devices that allow observation of cells moving through precisely defined geometries at high spatial and temporal resolution, we determined nuclear deformability as a critical factor in the cells' ability to pass through constrictions smaller than the size of the nucleus. Furthermore, we found that cells with reduced levels of the nuclear envelope proteins lamins A/C, which are the main determinants of nuclear stiffness, passed significantly faster through narrow constrictions during active migration and passive perfusion. Given recent reports that many human cancers have altered lamin expression, our findings suggest a novel biophysical mechanism by which changes in nuclear structure and composition may promote cancer cell invasion and metastasis.
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Abstract
A conserved organizational feature of eukaryotic nuclei is the peripheral heterochromatin compartment, which provides a protected area for epigenetically silent genes and gene-poor DNA. In metazoan cells this compartment is associated with the nuclear lamina, the protein meshwork at the inner edge of the nucleus. Heterochromatin-nuclear lamina interactions promote epigenetic gene silencing, which may drive many normal and diseased biological processes. We recently obtained evidence that a previously unstudied human protein, PRR14, participates in the tethering of heterochromatin to the inner nuclear periphery. PRR14 associates with the nuclear lamina and attaches to heterochromatin through its binding partner, heterochromatin protein 1 (HP1). After disassembly early in mitosis, PRR14 reassembles in two steps, first binding to anaphase chromosomes through HP1, followed by association with the nuclear lamina in telophase. PRR14 may thereby play a role in specifying HP1-bound heterochromatin for reattachment to the nuclear lamina at mitotic exit. Here we review the relevant literature, summarize our initial work, and provide additional comments and findings.
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Affiliation(s)
- Andrey Poleshko
- Fox Chase Cancer Center; Institute for Cancer Research; Philadelphia, PA USA
| | - Richard A Katz
- Fox Chase Cancer Center; Institute for Cancer Research; Philadelphia, PA 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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