101
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Bianchi A, Manti PG, Lucini F, Lanzuolo C. Mechanotransduction, nuclear architecture and epigenetics in Emery Dreifuss Muscular Dystrophy: tous pour un, un pour tous. Nucleus 2019; 9:276-290. [PMID: 29619865 PMCID: PMC5973142 DOI: 10.1080/19491034.2018.1460044] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The alteration of the several roles that Lamin A/C plays in the mammalian cell leads to a broad spectrum of pathologies that – all together – are named laminopathies. Among those, the Emery Dreifuss Muscular Dystrophy (EDMD) is of particular interest as, despite the several known mutations of Lamin A/C, the genotype–phenotype correlation still remains poorly understood; this suggests that the epigenetic background of patients might play an important role during the time course of the disease. Historically, both a mechanical role of Lamin A/C and a regulative one have been suggested as the driving force of laminopathies; however, those two hypotheses are not mutually exclusive. Recent scientific evidence shows that Lamin A/C sustains the correct gene expression at the epigenetic level thanks to the Lamina Associated Domains (LADs) reorganization and the crosstalk with the Polycomb Group of Proteins (PcG). Furthermore, the PcG-dependent histone mark H3K27me3 increases under mechanical stress, finally pointing out the link between the mechano-properties of the nuclear lamina and epigenetics. Here, we summarize the emerging mechanisms that could explain the high variability seen in Emery Dreifuss muscular dystrophy.
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Affiliation(s)
- Andrea Bianchi
- a CNR Institute of Cell Biology and Neurobiology, Istituto di Ricovero e Cura a Carattere Scientifico Fondazione Santa Lucia , Rome , Italy.,b Istituto Nazionale Genetica Molecolare Romeo ed Enrica Invernizzi , Milan , Italy
| | | | - Federica Lucini
- b Istituto Nazionale Genetica Molecolare Romeo ed Enrica Invernizzi , Milan , Italy
| | - Chiara Lanzuolo
- a CNR Institute of Cell Biology and Neurobiology, Istituto di Ricovero e Cura a Carattere Scientifico Fondazione Santa Lucia , Rome , Italy.,b Istituto Nazionale Genetica Molecolare Romeo ed Enrica Invernizzi , Milan , Italy.,c Istituto di Ricovero e Cura a Carattere Scientifico Fondazione Santa Lucia , Rome , Italy
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102
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Figueiras E, Silvestre OF, Ihalainen TO, Nieder JB. Phasor-assisted nanoscopy reveals differences in the spatial organization of major nuclear lamina proteins. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1866:118530. [PMID: 31415840 DOI: 10.1016/j.bbamcr.2019.118530] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 07/18/2019] [Accepted: 08/05/2019] [Indexed: 11/15/2022]
Abstract
Phasor-assisted Metal Induced Energy Transfer-Fluorescence Lifetime Imaging Microscopy (MIET-FLIM) nanoscopy is introduced as a powerful tool for functional cell biology research. Thin metal substrates can be used to obtain axial super-resolution via nanoscale distance-dependent MIET from fluorescent dyes towards a nearby metal layer, thereby creating fluorescence lifetime contrast between dyes located at different nanoscale distance from the metal. Such data can be used to achieve axially super-resolved microscopy images, a process known as MIET-FLIM nanoscopy. Suitability of the phasor approach in MIET-FLIM nanoscopy is first demonstrated using nanopatterned substrates, and furthermore applied to characterize the distance distribution of the epithelial basal membrane of a biological cell from the gold substrate. The phasor plot of an entire cell can be used to characterize the full Förster resonance energy transfer (FRET) trajectory as a large distance heterogeneity within the sensing range of about 100 nm from the metal surface is present due to the extended shape of cell with curvatures. In contrast, the different proteins of nuclear lamina show strong confinement close to the nuclear envelope in nanoscale. We find the lamin B layer resides in average at shorter distances from the gold surface compared to the lamin A/C layer located in more extended ranges. This and the observed heterogeneity of the protein layer thicknesses suggests that A- and B-type lamins form distinct networks in the nuclear lamina. Our results provide detailed insights for the study of the different roles of lamin proteins in chromatin tethering and nuclear mechanics.
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Affiliation(s)
- Edite Figueiras
- Department of Nanophotonics, Ultrafast Bio- and Nanophotonics Group, INL - International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga s/n, 4715-330 Braga, Portugal
| | - Oscar F Silvestre
- Department of Nanophotonics, Ultrafast Bio- and Nanophotonics Group, INL - International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga s/n, 4715-330 Braga, Portugal
| | - Teemu O Ihalainen
- Faculty of Medicine and Health Technology, BioMediTech, Tampere University, 33014 Tampere, Finland
| | - Jana B Nieder
- Department of Nanophotonics, Ultrafast Bio- and Nanophotonics Group, INL - International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga s/n, 4715-330 Braga, Portugal.
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103
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Stephens AD, Liu PZ, Kandula V, Chen H, Almassalha LM, Herman C, Backman V, O’Halloran T, Adam SA, Goldman RD, Banigan EJ, Marko JF. Physicochemical mechanotransduction alters nuclear shape and mechanics via heterochromatin formation. Mol Biol Cell 2019; 30:2320-2330. [PMID: 31365328 PMCID: PMC6743459 DOI: 10.1091/mbc.e19-05-0286] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 06/11/2019] [Indexed: 12/12/2022] Open
Abstract
The nucleus houses, organizes, and protects chromatin to ensure genome integrity and proper gene expression, but how the nucleus adapts mechanically to changes in the extracellular environment is poorly understood. Recent studies have revealed that extracellular physical stresses induce chromatin compaction via mechanotransductive processes. We report that increased extracellular multivalent cations lead to increased heterochromatin levels through activation of mechanosensitive ion channels (MSCs), without large-scale cell stretching. In cells with perturbed chromatin or lamins, this increase in heterochromatin suppresses nuclear blebbing associated with nuclear rupture and DNA damage. Through micromanipulation force measurements, we show that this increase in heterochromatin increases chromatin-based nuclear rigidity, which protects nuclear morphology and function. In addition, transduction of elevated extracellular cations rescues nuclear morphology in model and patient cells of human diseases, including progeria and the breast cancer model cell line MDA-MB-231. We conclude that nuclear mechanics, morphology, and function can be modulated by cell sensing of the extracellular environment through MSCs and consequent changes to histone modification state and chromatin-based nuclear rigidity.
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Affiliation(s)
- Andrew D. Stephens
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208
| | - Patrick Z. Liu
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208
| | - Viswajit Kandula
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208
| | - Haimei Chen
- Department of Chemistry, Northwestern University, Evanston, IL 60208
| | - Luay M. Almassalha
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208
| | - Cameron Herman
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208
| | - Vadim Backman
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208
| | - Thomas O’Halloran
- Department of Chemistry, Northwestern University, Evanston, IL 60208
| | - Stephen A. Adam
- Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611
| | - Robert D. Goldman
- Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611
| | - Edward J. Banigan
- Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208
- Institute for Medical Engineering and Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - John F. Marko
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208
- Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208
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104
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Mechanosensing by the Lamina Protects against Nuclear Rupture, DNA Damage, and Cell-Cycle Arrest. Dev Cell 2019; 49:920-935.e5. [PMID: 31105008 PMCID: PMC6581604 DOI: 10.1016/j.devcel.2019.04.020] [Citation(s) in RCA: 191] [Impact Index Per Article: 38.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 02/20/2019] [Accepted: 04/16/2019] [Indexed: 01/01/2023]
Abstract
Whether cell forces or extracellular matrix (ECM) can impact genome integrity is largely unclear. Here, acute perturbations (∼1 h) to actomyosin stress or ECM elasticity cause rapid and reversible changes in lamin-A, DNA damage, and cell cycle. The findings are especially relevant to organs such as the heart because DNA damage permanently arrests cardiomyocyte proliferation shortly after birth and thereby eliminates regeneration after injury including heart attack. Embryonic hearts, cardiac-differentiated iPS cells (induced pluripotent stem cells), and various nonmuscle cell types all show that actomyosin-driven nuclear rupture causes cytoplasmic mis-localization of DNA repair factors and excess DNA damage. Binucleation and micronuclei increase as telomeres shorten, which all favor cell-cycle arrest. Deficiencies in lamin-A and repair factors exacerbate these effects, but lamin-A-associated defects are rescued by repair factor overexpression and also by contractility modulators in clinical trials. Contractile cells on stiff ECM normally exhibit low phosphorylation and slow degradation of lamin-A by matrix-metalloprotease-2 (MMP2), and inhibition of this lamin-A turnover and also actomyosin contractility are seen to minimize DNA damage. Lamin-A is thus stress stabilized to mechano-protect the genome.
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105
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Abstract
Cellular behavior is continuously affected by microenvironmental forces through the process of mechanotransduction, in which mechanical stimuli are rapidly converted to biochemical responses. Mounting evidence suggests that the nucleus itself is a mechanoresponsive element, reacting to cytoskeletal forces and mediating downstream biochemical responses. The nucleus responds through a host of mechanisms, including partial unfolding, conformational changes, and phosphorylation of nuclear envelope proteins; modulation of nuclear import/export; and altered chromatin organization, resulting in transcriptional changes. It is unclear which of these events present direct mechanotransduction processes and which are downstream of other mechanotransduction pathways. We critically review and discuss the current evidence for nuclear mechanotransduction, particularly in the context of stem cell fate, a largely unexplored topic, and in disease, where an improved understanding of nuclear mechanotransduction is beginning to open new treatment avenues. Finally, we discuss innovative technological developments that will allow outstanding questions in the rapidly growing field of nuclear mechanotransduction to be answered.
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Affiliation(s)
- Melanie Maurer
- Meinig School of Biomedical Engineering and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York 14853, USA; ,
| | - Jan Lammerding
- Meinig School of Biomedical Engineering and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York 14853, USA; ,
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106
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Stephens AD, Banigan EJ, Marko JF. Chromatin's physical properties shape the nucleus and its functions. Curr Opin Cell Biol 2019; 58:76-84. [PMID: 30889417 PMCID: PMC6692209 DOI: 10.1016/j.ceb.2019.02.006] [Citation(s) in RCA: 99] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 02/06/2019] [Accepted: 02/20/2019] [Indexed: 12/13/2022]
Abstract
The cell nucleus encloses, organizes, and protects the genome. Chromatin maintains nuclear mechanical stability and shape in coordination with lamins and the cytoskeleton. Abnormal nuclear shape is a diagnostic marker for human diseases, and it can cause nuclear dysfunction. Chromatin mechanics underlies this link, as alterations to chromatin and its physical properties can disrupt or rescue nuclear shape. The cell can regulate nuclear shape through mechanotransduction pathways that sense and respond to extracellular cues, thus modulating chromatin compaction and rigidity. These findings reveal how chromatin's physical properties can regulate cellular function and drive abnormal nuclear morphology and dysfunction in disease.
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Affiliation(s)
- Andrew D Stephens
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, United States.
| | - Edward J Banigan
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, United States
| | - John F Marko
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, United States; Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208, United States.
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107
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Fišerová J, Maninová M, Sieger T, Uhlířová J, Šebestová L, Efenberková M, Čapek M, Fišer K, Hozák P. Nuclear pore protein TPR associates with lamin B1 and affects nuclear lamina organization and nuclear pore distribution. Cell Mol Life Sci 2019; 76:2199-2216. [PMID: 30762072 PMCID: PMC11105453 DOI: 10.1007/s00018-019-03037-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 01/22/2019] [Accepted: 02/01/2019] [Indexed: 10/27/2022]
Abstract
The organization of the nuclear periphery is crucial for many nuclear functions. Nuclear lamins form dense network at the nuclear periphery and play a substantial role in chromatin organization, transcription regulation and in organization of nuclear pore complexes (NPCs). Here, we show that TPR, the protein located preferentially within the nuclear baskets of NPCs, associates with lamin B1. The depletion of TPR affects the organization of lamin B1 but not lamin A/C within the nuclear lamina as shown by stimulated emission depletion microscopy. Finally, reduction of TPR affects the distribution of NPCs within the nuclear envelope and the effect can be reversed by simultaneous knock-down of lamin A/C or the overexpression of lamin B1. Our work suggests a novel role for the TPR at the nuclear periphery: the TPR contributes to the organization of the nuclear lamina and in cooperation with lamins guards the interphase assembly of nuclear pore complexes.
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Affiliation(s)
- Jindřiška Fišerová
- Department of Biology of the Cell Nucleus, Institute of Molecular Genetics CAS, v.v.i., Vídeňská 1083, 142 00, Prague, Czech Republic.
| | - Miloslava Maninová
- Department of Biology of the Cell Nucleus, Institute of Molecular Genetics CAS, v.v.i., Vídeňská 1083, 142 00, Prague, Czech Republic
| | - Tomáš Sieger
- Department of Cybernetics, Faculty of Electrical Engineering, Czech Technical University in Prague, Prague, Czech Republic
| | - Jana Uhlířová
- Department of Biology of the Cell Nucleus, Institute of Molecular Genetics CAS, v.v.i., Vídeňská 1083, 142 00, Prague, Czech Republic
| | - Lenka Šebestová
- Department of Biology of the Cell Nucleus, Institute of Molecular Genetics CAS, v.v.i., Vídeňská 1083, 142 00, Prague, Czech Republic
| | - Michaela Efenberková
- Microscopy Centre-LM and EM, Institute of Molecular Genetics CAS, v.v.i., Vídeňská 1083, 142 00, Prague, Czech Republic
| | - Martin Čapek
- Microscopy Centre-LM and EM, Institute of Molecular Genetics CAS, v.v.i., Vídeňská 1083, 142 00, Prague, Czech Republic
| | - Karel Fišer
- CLIP Laboratories, Department of Paediatric Haematology and Oncology, Second Faculty of Medicine, Charles University and University Hospital Motol Prague, V Úvalu 84, 150 06, Prague, Czech Republic
| | - Pavel Hozák
- Department of Biology of the Cell Nucleus, Institute of Molecular Genetics CAS, v.v.i., Vídeňská 1083, 142 00, Prague, Czech Republic
- Microscopy Centre-LM and EM, Institute of Molecular Genetics CAS, v.v.i., Vídeňská 1083, 142 00, Prague, Czech Republic
- Division BIOCEV, Institute of Molecular Genetics CAS, v.v.i., Průmyslová 595, Vestec, 252 50, Prague, Czech Republic
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108
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Sidorenko E, Vartiainen MK. Nucleoskeletal regulation of transcription: Actin on MRTF. Exp Biol Med (Maywood) 2019; 244:1372-1381. [PMID: 31142145 DOI: 10.1177/1535370219854669] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Myocardin-related transcription factor A (MRTF-A) and serum response factor (SRF) form an essential transcriptional complex that regulates the expression of many cytoskeletal genes in response to dynamic changes in the actin cytoskeleton. The nucleoskeleton, a “dynamic network of networks,” consists of numerous proteins that contribute to nuclear shape and to its various functions, including gene expression. In this review, we will discuss recent work that has identified many nucleoskeletal proteins, such as nuclear lamina and lamina-associated proteins, nuclear actin, and the linker of the cytoskeleton and nucleoskeleton complex as important regulators of MRTF-A/SRF transcriptional activity, especially in the context of mechanical control of transcription. Impact statement Regulation of gene expression is a fundamental cellular process that ensures the appropriate response of a cell to its surroundings. Alongside biochemical signals, mechanical cues, such as substrate rigidity, have been recognized as key regulators of gene expression. Nucleoskeletal components play an important role in mechanoresponsive transcription, particularly in controlling the activity of MRTF-A/SRF transcription factors. This ensures that the cell can balance the internal and external mechanical forces by fine-tuning the expression of cytoskeletal genes.
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Affiliation(s)
- Ekaterina Sidorenko
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki 00014, Finland
| | - Maria K Vartiainen
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki 00014, Finland
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109
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Ranade D, Pradhan R, Jayakrishnan M, Hegde S, Sengupta K. Lamin A/C and Emerin depletion impacts chromatin organization and dynamics in the interphase nucleus. BMC Mol Cell Biol 2019; 20:11. [PMID: 31117946 PMCID: PMC6532135 DOI: 10.1186/s12860-019-0192-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Accepted: 04/16/2019] [Indexed: 12/26/2022] Open
Abstract
Background Nuclear lamins are type V intermediate filament proteins that maintain nuclear structure and function. Furthermore, Emerin - an interactor of Lamin A/C, facilitates crosstalk between the cytoskeleton and the nucleus as it also interacts with actin and Nuclear Myosin 1 (NM1). Results Here we show that the depletion of Lamin A/C or Emerin, alters the localization of the nuclear motor protein - Nuclear Myosin 1 (NM1) that manifests as an increase in NM1 foci in the nucleus and are rescued to basal levels upon the combined knockdown of Lamin A/C and Emerin. Furthermore, Lamin A/C-Emerin co-depletion destabilizes cytoskeletal organization as it increases actin stress fibers. This further impinges on nuclear organization, as it enhances chromatin mobility more toward the nuclear interior in Lamin A/C-Emerin co-depleted cells. This enhanced chromatin mobility was restored to basal levels either upon inhibition of Nuclear Myosin 1 (NM1) activity or actin depolymerization. In addition, the combined loss of Lamin A/C and Emerin alters the otherwise highly conserved spatial positions of chromosome territories. Furthermore, knockdown of Lamin A/C or Lamin A/C-Emerin combined, deregulates expression levels of a candidate subset of genes. Amongst these genes, both KLK10 (Chr.19, Lamina Associated Domain (LAD+)) and MADH2 (Chr.18, LAD-) were significantly repressed, while BCL2L12 (Chr.19, LAD-) is de-repressed. These genes differentially reposition with respect to the nuclear envelope. Conclusions Taken together, these studies underscore a remarkable interplay between Lamin A/C and Emerin in modulating cytoskeletal organization of actin and NM1 that impinges on chromatin dynamics and function in the interphase nucleus. Electronic supplementary material The online version of this article (10.1186/s12860-019-0192-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Devika Ranade
- Indian Institute of Science Education and Research (IISER)-Pune, Dr. Homi Bhabha Road, Biology, Room#B-216, 1st Floor, Main Building, Pashan, Pune, Maharashtra, 411008, India
| | - Roopali Pradhan
- Indian Institute of Science Education and Research (IISER)-Pune, Dr. Homi Bhabha Road, Biology, Room#B-216, 1st Floor, Main Building, Pashan, Pune, Maharashtra, 411008, India
| | - Muhunden Jayakrishnan
- Indian Institute of Science Education and Research (IISER)-Pune, Dr. Homi Bhabha Road, Biology, Room#B-216, 1st Floor, Main Building, Pashan, Pune, Maharashtra, 411008, India
| | - Sushmitha Hegde
- Indian Institute of Science Education and Research (IISER)-Pune, Dr. Homi Bhabha Road, Biology, Room#B-216, 1st Floor, Main Building, Pashan, Pune, Maharashtra, 411008, India
| | - Kundan Sengupta
- Indian Institute of Science Education and Research (IISER)-Pune, Dr. Homi Bhabha Road, Biology, Room#B-216, 1st Floor, Main Building, Pashan, Pune, Maharashtra, 411008, India.
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110
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Guerreiro I, Kind J. Spatial chromatin organization and gene regulation at the nuclear lamina. Curr Opin Genet Dev 2019; 55:19-25. [PMID: 31112905 DOI: 10.1016/j.gde.2019.04.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 03/13/2019] [Accepted: 04/15/2019] [Indexed: 12/31/2022]
Abstract
The nuclear lamina (NL) consists of a thin meshwork of lamins and associated proteins that lines the inner nuclear membrane (INM). In metazoan nuclei, a large proportion of the genome contacts the NL in broad lamina-associated domains (LADs). Contacts of the NL with the genome are believed to aid the spatial organization of chromosomes and contribute to the regulation of transcription. Here, we will focus on recent insights in the structural organization of the genome at the NL and the role of this organization in the regulation of gene expression.
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Affiliation(s)
- Isabel Guerreiro
- Oncode Institute, Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jop Kind
- Oncode Institute, Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, The Netherlands.
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111
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Kittisopikul M, Virtanen L, Taimen P, Goldman RD. Quantitative Analysis of Nuclear Lamins Imaged by Super-Resolution Light Microscopy. Cells 2019; 8:E361. [PMID: 31003483 PMCID: PMC6524165 DOI: 10.3390/cells8040361] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 04/13/2019] [Accepted: 04/14/2019] [Indexed: 11/20/2022] Open
Abstract
The nuclear lamina consists of a dense fibrous meshwork of nuclear lamins, Type V intermediate filaments, and is ~14 nm thick according to recent cryo-electron tomography studies. Recent advances in light microscopy have extended the resolution to a scale allowing for the fine structure of the lamina to be imaged in the context of the whole nucleus. We review quantitative approaches to analyze the imaging data of the nuclear lamina as acquired by structured illumination microscopy (SIM) and single molecule localization microscopy (SMLM), as well as the requisite cell preparation techniques. In particular, we discuss the application of steerable filters and graph-based methods to segment the structure of the four mammalian lamin isoforms (A, C, B1, and B2) and extract quantitative information.
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Affiliation(s)
- Mark Kittisopikul
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
- Department of Biophysics, UT Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Laura Virtanen
- Institute of Biomedicine, Research Center for Cancer, Infections and Immunity, University of Turku, 20520 Turku, Finland.
| | - Pekka Taimen
- Institute of Biomedicine, Research Center for Cancer, Infections and Immunity, University of Turku, 20520 Turku, Finland.
- Department of Pathology, Turku University Hospital, 20520 Turku, Finland.
| | - Robert D Goldman
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
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112
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Lim JSY, Wright GD, Burke B, Xie W. A user-interactive algorithm quantifying nuclear pore complex distribution within the nuclear lamina network in single molecular localization microscopic image. Methods 2019; 157:42-46. [PMID: 30268406 DOI: 10.1016/j.ymeth.2018.09.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 09/04/2018] [Accepted: 09/25/2018] [Indexed: 11/17/2022] Open
Abstract
For decades, components of the mammalian nuclear envelope (NE), such as the nuclear lamina and nuclear pore complexes (NPCs), have been largely resistant to quantitative cell biological analysis using conventional fluorescence microscopy. This is in part due to their sub diffraction limit dimensions. Super-resolution microscopy, a major advancement in cell biology research, has now made possible the acquisition of images in which nuclear lamin networks and single NPCs can be resolved in intact mammalian somatic cells. In particular, single molecule localization microscopy is able to generate data sets that are accurate enough to allow detailed quantitative analysis. Here we describe an algorithm that will identify the centroid of single NPCs and will determine their localization relative to the distribution of lamin protein filaments. Using this algorithm, a percentage of NPCs localized within the nuclear lamin network was accurately calculated, that could be compared between cells expressing different lamin complements. With modifications tweaked according to user specified sample images, this algorithm serves as a semi-automatic and fast computational tool to quantify and compare the localization and distribution of two or more cellular components at the nanometre scale.
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Affiliation(s)
- John S Y Lim
- Institute of Medical Biology, Agency for Science, Technology and Research, 8A Biomedical Grove, #06-06 Immunos, Singapore 138648, Singapore; Skin Research Institute of Singapore, Agency for Science, Technology and Research, Singapore
| | - Graham D Wright
- Institute of Medical Biology, Agency for Science, Technology and Research, 8A Biomedical Grove, #06-06 Immunos, Singapore 138648, Singapore; Skin Research Institute of Singapore, Agency for Science, Technology and Research, Singapore
| | - Brian Burke
- Institute of Medical Biology, Agency for Science, Technology and Research, 8A Biomedical Grove, #06-06 Immunos, Singapore 138648, Singapore
| | - Wei Xie
- Institute of Medical Biology, Agency for Science, Technology and Research, 8A Biomedical Grove, #06-06 Immunos, Singapore 138648, Singapore.
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113
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Hah J, Kim DH. Deciphering Nuclear Mechanobiology in Laminopathy. Cells 2019; 8:E231. [PMID: 30862117 PMCID: PMC6468464 DOI: 10.3390/cells8030231] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 02/23/2019] [Accepted: 03/05/2019] [Indexed: 12/13/2022] Open
Abstract
Extracellular mechanical stimuli are translated into biochemical signals inside the cell via mechanotransduction. The nucleus plays a critical role in mechanoregulation, which encompasses mechanosensing and mechanotransduction. The nuclear lamina underlying the inner nuclear membrane not only maintains the structural integrity, but also connects the cytoskeleton to the nuclear envelope. Lamin mutations, therefore, dysregulate the nuclear response, resulting in abnormal mechanoregulations, and ultimately, disease progression. Impaired mechanoregulations even induce malfunction in nuclear positioning, cell migration, mechanosensation, as well as differentiation. To know how to overcome laminopathies, we need to understand the mechanisms of laminopathies in a mechanobiological way. Recently, emerging studies have demonstrated the varying defects from lamin mutation in cellular homeostasis within mechanical surroundings. Therefore, this review summarizes recent findings highlighting the role of lamins, the architecture of nuclear lamina, and their disease relevance in the context of nuclear mechanobiology. We will also provide an overview of the differentiation of cellular mechanics in laminopathy.
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Affiliation(s)
- Jungwon Hah
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea.
| | - Dong-Hwee Kim
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea.
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114
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Nmezi B, Xu J, Fu R, Armiger TJ, Rodriguez-Bey G, Powell JS, Ma H, Sullivan M, Tu Y, Chen NY, Young SG, Stolz DB, Dahl KN, Liu Y, Padiath QS. Concentric organization of A- and B-type lamins predicts their distinct roles in the spatial organization and stability of the nuclear lamina. Proc Natl Acad Sci U S A 2019; 116:4307-4315. [PMID: 30765529 PMCID: PMC6410836 DOI: 10.1073/pnas.1810070116] [Citation(s) in RCA: 87] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The nuclear lamina is an intermediate filament meshwork adjacent to the inner nuclear membrane (INM) that plays a critical role in maintaining nuclear shape and regulating gene expression through chromatin interactions. Studies have demonstrated that A- and B-type lamins, the filamentous proteins that make up the nuclear lamina, form independent but interacting networks. However, whether these lamin subtypes exhibit a distinct spatial organization or whether their organization has any functional consequences is unknown. Using stochastic optical reconstruction microscopy (STORM) our studies reveal that lamin B1 and lamin A/C form concentric but overlapping networks, with lamin B1 forming the outer concentric ring located adjacent to the INM. The more peripheral localization of lamin B1 is mediated by its carboxyl-terminal farnesyl group. Lamin B1 localization is also curvature- and strain-dependent, while the localization of lamin A/C is not. We also show that lamin B1's outer-facing localization stabilizes nuclear shape by restraining outward protrusions of the lamin A/C network. These two findings, that lamin B1 forms an outer concentric ring and that its localization is energy-dependent, are significant as they suggest a distinct model for the nuclear lamina-one that is able to predict its behavior and clarifies the distinct roles of individual nuclear lamin proteins and the consequences of their perturbation.
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Affiliation(s)
- Bruce Nmezi
- Department of Human Genetics, University of Pittsburgh, Pittsburgh, PA 15261
| | - Jianquan Xu
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15213
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15213
| | - Rao Fu
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15213
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15213
- College of Chemical Engineering, Northeast Electric Power University, Jilin Province, China 132012
| | - Travis J Armiger
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213
| | | | - Juliana S Powell
- Department of Human Genetics, University of Pittsburgh, Pittsburgh, PA 15261
| | - Hongqiang Ma
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15213
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15213
| | - Mara Sullivan
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA 15213
| | - Yiping Tu
- Department of Medicine, University of California, Los Angeles, CA 90095
| | - Natalie Y Chen
- Department of Medicine, University of California, Los Angeles, CA 90095
| | - Stephen G Young
- Department of Medicine, University of California, Los Angeles, CA 90095
| | - Donna B Stolz
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA 15213
| | - Kris Noel Dahl
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213;
| | - Yang Liu
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15213;
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15213
| | - Quasar S Padiath
- Department of Human Genetics, University of Pittsburgh, Pittsburgh, PA 15261;
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115
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Grafe M, Batsios P, Meyer I, Lisin D, Baumann O, Goldberg MW, Gräf R. Supramolecular Structures of the Dictyostelium Lamin NE81. Cells 2019; 8:cells8020162. [PMID: 30781468 PMCID: PMC6406624 DOI: 10.3390/cells8020162] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 02/12/2019] [Accepted: 02/15/2019] [Indexed: 12/27/2022] Open
Abstract
Nuclear lamins are nucleus-specific intermediate filaments (IF) found at the inner nuclear membrane (INM) of the nuclear envelope (NE). Together with nuclear envelope transmembrane proteins, they form the nuclear lamina and are crucial for gene regulation and mechanical robustness of the nucleus and the whole cell. Recently, we characterized Dictyostelium NE81 as an evolutionarily conserved lamin-like protein, both on the sequence and functional level. Here, we show on the structural level that the Dictyostelium NE81 is also capable of assembling into filaments, just as metazoan lamin filament assemblies. Using field-emission scanning electron microscopy, we show that NE81 expressed in Xenopous oocytes forms filamentous structures with an overall appearance highly reminiscent of Xenopus lamin B2. The in vitro assembly properties of recombinant His-tagged NE81 purified from Dictyostelium extracts are very similar to those of metazoan lamins. Super-resolution stimulated emission depletion (STED) and expansion microscopy (ExM), as well as transmission electron microscopy of negatively stained purified NE81, demonstrated its capability of forming filamentous structures under low-ionic-strength conditions. These results recommend Dictyostelium as a non-mammalian model organism with a well-characterized nuclear envelope involving all relevant protein components known in animal cells.
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Affiliation(s)
- Marianne Grafe
- Department of Cell Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany.
| | - Petros Batsios
- Department of Cell Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany.
| | - Irene Meyer
- Department of Cell Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany.
| | - Daria Lisin
- Department of Cell Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany.
| | - Otto Baumann
- Department of Animal Physiology, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany.
| | - Martin W Goldberg
- Department of Biosciences, Durham University, Science Laboratories, South Road, Durham DH1 3LE, UK.
| | - Ralph Gräf
- Department of Cell Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany.
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116
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Weber MS, Wojtynek M, Medalia O. Cellular and Structural Studies of Eukaryotic Cells by Cryo-Electron Tomography. Cells 2019; 8:E57. [PMID: 30654455 PMCID: PMC6356268 DOI: 10.3390/cells8010057] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 01/09/2019] [Accepted: 01/10/2019] [Indexed: 11/23/2022] Open
Abstract
The architecture of protein assemblies and their remodeling during physiological processes is fundamental to cells. Therefore, providing high-resolution snapshots of macromolecular complexes in their native environment is of major importance for understanding the molecular biology of the cell. Cellular structural biology by means of cryo-electron tomography (cryo-ET) offers unique insights into cellular processes at an unprecedented resolution. Recent technological advances have enabled the detection of single impinging electrons and improved the contrast of electron microscopic imaging, thereby significantly increasing the sensitivity and resolution. Moreover, various sample preparation approaches have paved the way to observe every part of a eukaryotic cell, and even multicellular specimens, under the electron beam. Imaging of macromolecular machineries at high resolution directly within their native environment is thereby becoming reality. In this review, we discuss several sample preparation and labeling techniques that allow the visualization and identification of macromolecular assemblies in situ, and demonstrate how these methods have been used to study eukaryotic cellular landscapes.
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Affiliation(s)
- Miriam Sarah Weber
- Department of Biochemistry, University of Zürich, 8057 Zürich, Switzerland.
| | - Matthias Wojtynek
- Department of Biochemistry, University of Zürich, 8057 Zürich, Switzerland.
- Department of Biology, Institute of Biochemistry, ETH Zürich, 8093 Zürich, Switzerland.
| | - Ohad Medalia
- Department of Biochemistry, University of Zürich, 8057 Zürich, Switzerland.
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84120, Israel.
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117
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Manley HR, Keightley MC, Lieschke GJ. The Neutrophil Nucleus: An Important Influence on Neutrophil Migration and Function. Front Immunol 2018; 9:2867. [PMID: 30564248 PMCID: PMC6288403 DOI: 10.3389/fimmu.2018.02867] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 11/21/2018] [Indexed: 11/13/2022] Open
Abstract
Neutrophil nuclear morphology has historically been used in haematology for neutrophil identification and characterisation, but its exact role in neutrophil function has remained enigmatic. During maturation, segmentation of the neutrophil nucleus into its mature, multi-lobulated shape is accompanied by distinct changes in nuclear envelope composition, resulting in a unique nucleus that is believed to be imbued with extraordinary nuclear flexibility. As a rate-limiting factor for cell migration, nuclear morphology and biomechanics are particularly important in the context of neutrophil migration during immune responses. Being an extremely plastic and fast migrating cell type, it is to be expected that neutrophils have an especially deformable nucleus. However, many questions still surround the dynamic capacities of the neutrophil nucleus, and which nuclear and cytoskeletal elements determine these dynamics. The biomechanics of the neutrophil nucleus should also be considered for their influences on the production of neutrophil extracellular traps (NETs), given this process sees the release of chromatin "nets" from nucleoplasm to extracellular space. Although past studies have investigated neutrophil nuclear composition and shape, in a new era of more sophisticated biomechanical and genetic techniques, 3D migration studies, and higher resolution microscopy we now have the ability to further investigate and understand neutrophil nuclear plasticity at an unprecedented level. This review addresses what is currently understood about neutrophil nuclear structure and its role in migration and the release of NETs, whilst highlighting open questions surrounding neutrophil nuclear dynamics.
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Affiliation(s)
- Harriet R Manley
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, Australia
| | | | - Graham J Lieschke
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, Australia
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118
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González-Cruz RD, Dahl KN, Darling EM. The Emerging Role of Lamin C as an Important LMNA Isoform in Mechanophenotype. Front Cell Dev Biol 2018; 6:151. [PMID: 30450357 PMCID: PMC6224339 DOI: 10.3389/fcell.2018.00151] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 10/15/2018] [Indexed: 12/17/2022] Open
Abstract
Lamin A and lamin C isoforms of the gene LMNA are major structural and mechanotransductive components of the nuclear lamina. Previous reports have proposed lamin A as the isoform with the most dominant contributions to cellular mechanophenotype. Recently, expression of lamin C has also been shown to strongly correlate to cellular elastic and viscoelastic properties. Nevertheless, LMNA isoforms exist as part of a network that collectively provides structural integrity to the nucleus and their expression is ultimately regulated in a cell-specific manner. Thus, they have importance in mechanotransduction and structural integrity of the nucleus as well as potential candidates for biomarkers of whole-cell mechanophenotype. Therefore, a fuller discussion of lamin isoforms as mechanophenotypic biomarkers should compare both individual and ratiometric isoform contributions toward whole-cell mechanophenotype across different cell types. In this perspective, we discuss the distinctions between the mechanophenotypic correlations of individual and ratiometric lamins A:B1, C:B1, (A + C):B1, and C:A across cells from different lineages, demonstrating that the collective contribution of ratiometric lamin (A + C):B1 isoforms exhibited the strongest correlation to whole-cell stiffness. Additionally, we highlight the potential roles of lamin isoform ratios as indicators of mechanophenotypic change in differentiation and disease to demonstrate that the contributions of individual and collective lamin isoforms can occur as both static and dynamic biomarkers of mechanophenotype.
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Affiliation(s)
| | - Kris N Dahl
- Department of Chemical Engineering, Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, United States
| | - Eric M Darling
- Center for Biomedical Engineering, Brown University, Providence, RI, United States.,Department of Molecular Pharmacology, Physiology and Biotechnology, School of Engineering, Department of Orthopaedics, Brown University, Providence, RI, United States
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119
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Brull A, Morales Rodriguez B, Bonne G, Muchir A, Bertrand AT. The Pathogenesis and Therapies of Striated Muscle Laminopathies. Front Physiol 2018; 9:1533. [PMID: 30425656 PMCID: PMC6218675 DOI: 10.3389/fphys.2018.01533] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 10/11/2018] [Indexed: 01/04/2023] Open
Abstract
Emery-Dreifuss muscular dystrophy (EDMD) is a genetic condition characterized by early contractures, skeletal muscle weakness, and cardiomyopathy. During the last 20 years, various genetic approaches led to the identification of causal genes of EDMD and related disorders, all encoding nuclear envelope proteins. By their respective localization either at the inner nuclear membrane or the outer nuclear membrane, these proteins interact with each other and establish a connection between the nucleus and the cytoskeleton. Beside this physical link, these proteins are also involved in mechanotransduction, responding to environmental cues, such as increased tension of the cytoskeleton, by the activation or repression of specific sets of genes. This ability of cells to adapt to environmental conditions is altered in EDMD. Increased knowledge on the pathophysiology of EDMD has led to the development of drug or gene therapies that have been tested on mouse models. This review proposed an overview of the functions played by the different proteins involved in EDMD and related disorders and the current therapeutic approaches tested so far.
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Affiliation(s)
- Astrid Brull
- Sorbonne Université, INSERM, Institut de Myologie, Center of Research in Myology, UMRS 974, Paris, France
| | - Blanca Morales Rodriguez
- Sorbonne Université, INSERM, Institut de Myologie, Center of Research in Myology, UMRS 974, Paris, France.,Sanofi R&D, Chilly Mazarin, France
| | - Gisèle Bonne
- Sorbonne Université, INSERM, Institut de Myologie, Center of Research in Myology, UMRS 974, Paris, France
| | - Antoine Muchir
- Sorbonne Université, INSERM, Institut de Myologie, Center of Research in Myology, UMRS 974, Paris, France
| | - Anne T Bertrand
- Sorbonne Université, INSERM, Institut de Myologie, Center of Research in Myology, UMRS 974, Paris, France
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120
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Li BX, Chen J, Chao B, Zheng Y, Xiao X. A Lamin-Binding Ligand Inhibits Homologous Recombination Repair of DNA Double-Strand Breaks. ACS CENTRAL SCIENCE 2018; 4:1201-1210. [PMID: 30276254 PMCID: PMC6161055 DOI: 10.1021/acscentsci.8b00379] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Indexed: 05/02/2023]
Abstract
Nuclear lamins are type V intermediate filament proteins. Lamins, including LA, LB1, LB2, and LC, are the major protein components forming the nuclear lamina to support the mechanical stability of the mammalian cell nucleus. Increasing evidence has shown that LA participates in homologous recombination (HR) repair of DNA double-strand breaks (DSBs) . However, the mechanisms underlying this process are incompletely understood. We recently identified the first lamin-binding ligand 1 (LBL1) that directly binds LA and inhibited cancer cell growth. We provided here further mechanistic investigations of LBL1 and revealed that LA interacts with the HR recombinase Rad51 to protect Rad51 from degradation. LBL1 inhibits LA-Rad51 interaction leading to accelerated proteasome-mediated degradation of Rad51, culminating in inhibition of HR repair of DSBs. These results uncover a novel post-translational regulation of Rad51 by LA and suggest that targeting the LA-Rad51 axis may represent a promising strategy to develop cancer therapeutics.
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Affiliation(s)
- Bingbing X. Li
- Program
in Chemical Biology, Department of Physiology and Pharmacology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
- E-mail:
| | - Jingjin Chen
- Program
in Chemical Biology, Department of Physiology and Pharmacology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Bo Chao
- Program
in Chemical Biology, Department of Physiology and Pharmacology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Yixian Zheng
- Department
of Embryology, Carnegie Institution for
Science, 3520 San Martin
Drive, Baltimore, Maryland 21218, United States
| | - Xiangshu Xiao
- Program
in Chemical Biology, Department of Physiology and Pharmacology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
- Knight
Cancer Institute, Oregon Health & Science
University, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
- E-mail:
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121
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Abstract
Nuclear lamins are intermediate filament proteins that represent important structural components of metazoan nuclear envelopes (NEs). By combining proteomics and superresolution microscopy, we recently reported that both A- and B-type nuclear lamins form spatially distinct filament networks at the nuclear periphery of mouse fibroblasts. In particular, A-type lamins exhibit differential association with nuclear pore complexes (NPCs). Our studies reveal that the nuclear lamina network in mammalian somatic cells is less ordered and more complex than that of amphibian oocytes, the only other system in which the lamina has been visualized at high resolution. In addition, the NPC component Tpr likely links NPCs to the A-type lamin network, an association that appears to be regulated by C-terminal modification of various A-type lamin isoforms. Many questions remain, however, concerning the structure and assembly of lamin filaments, as well as with their mode of association with other nuclear components such as peripheral chromatin.
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Affiliation(s)
- Wei Xie
- a Laboratory of Nuclear Dynamics and Architecture, Institute of Medical Biology , Agency for Science, Technology and Research (A*STAR) , Immunos , Singapore
| | - Brian Burke
- a Laboratory of Nuclear Dynamics and Architecture, Institute of Medical Biology , Agency for Science, Technology and Research (A*STAR) , Immunos , Singapore
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122
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Lele TP, Dickinson RB, Gundersen GG. Mechanical principles of nuclear shaping and positioning. J Cell Biol 2018; 217:3330-3342. [PMID: 30194270 PMCID: PMC6168261 DOI: 10.1083/jcb.201804052] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 07/27/2018] [Accepted: 08/24/2018] [Indexed: 12/16/2022] Open
Abstract
Positioning and shaping the nucleus represents a mechanical challenge for the migrating cell because of its large size and resistance to deformation. Cells shape and position the nucleus by transmitting forces from the cytoskeleton onto the nuclear surface. This force transfer can occur through specialized linkages between the nuclear envelope and the cytoskeleton. In response, the nucleus can deform and/or it can move. Nuclear movement will occur when there is a net differential in mechanical force across the nucleus, while nuclear deformation will occur when mechanical forces overcome the mechanical resistance of the various structures that comprise the nucleus. In this perspective, we review current literature on the sources and magnitude of cellular forces exerted on the nucleus, the nuclear envelope proteins involved in transferring cellular forces, and the contribution of different nuclear structural components to the mechanical response of the nucleus to these forces.
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Affiliation(s)
- Tanmay P Lele
- Department of Chemical Engineering, University of Florida, Gainesville, FL .,Anatomy and Cell Biology, University of Florida, Gainesville, FL
| | | | - Gregg G Gundersen
- Department of Pathology and Cell Biology, Columbia University, New York, NY
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123
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Abstract
Pancreatic cancer is an aggressive and intractable malignancy with high mortality. This is due in part to a high resistance to chemotherapeutics and radiation treatment conferred by diverse regulatory mechanisms. Among these, constituents of the nuclear envelope play a significant role in regulating oncogenesis and pancreatic tumor biology, and this review focuses on three specific components and their roles in cancer. The LINC complex is a nuclear envelope component formed by proteins with SUN and KASH domains that interact in the periplasmic space of the nuclear envelope. These interactions functionally and structurally couple the cytoskeleton to chromatin and facilitates gene regulation informed by cytoplasmic activity. Furthermore, cancer cell invasiveness is impacted by LINC complex biology. The nuclear lamina is adjacent to the inner nuclear membrane of the nuclear envelope and can actively regulate chromatin in addition to providing structural integrity to the nucleus. A disrupted lamina can impart biophysical compromise to nuclear structure and function, as well as form dysfunctional micronuclei that may lead to genomic instability and chromothripsis. In close relationship to the nuclear lamina is the nuclear pore complex, a large megadalton structure that spans both outer and inner membranes of the nuclear envelope. The nuclear pore complex mediates bidirectional nucleocytoplasmic transport and is comprised of specialized proteins called nucleoporins that are overexpressed in many cancers and are diagnostic markers for oncogenesis. Furthermore, recent demonstration of gene regulatory functions for discrete nucleoporins independent of their nuclear trafficking function suggests that these proteins may contribute more to malignant phenotypes beyond serving as biomarkers. The nuclear envelope is thus a complex, intricate regulator of cell signaling, with roles in pancreatic tumorigenesis and general oncogenic transformation.
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Affiliation(s)
| | - Randolph S. Faustino
- Genetics and Genomics, Sanford Research, Sioux Falls, SD 57104, USA
- Department of Pediatrics, Sanford School of Medicine of the University of South Dakota, Sioux Falls, SD 57105, USA
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124
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Pascual-Reguant L, Blanco E, Galan S, Le Dily F, Cuartero Y, Serra-Bardenys G, Di Carlo V, Iturbide A, Cebrià-Costa JP, Nonell L, de Herreros AG, Di Croce L, Marti-Renom MA, Peiró S. Lamin B1 mapping reveals the existence of dynamic and functional euchromatin lamin B1 domains. Nat Commun 2018; 9:3420. [PMID: 30143639 PMCID: PMC6109041 DOI: 10.1038/s41467-018-05912-z] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 08/02/2018] [Indexed: 12/13/2022] Open
Abstract
Lamins (A/C and B) are major constituents of the nuclear lamina (NL). Structurally conserved lamina-associated domains (LADs) are formed by genomic regions that contact the NL. Lamins are also found in the nucleoplasm, with a yet unknown function. Here we map the genome-wide localization of lamin B1 in an euchromatin-enriched fraction of the mouse genome and follow its dynamics during the epithelial-to-mesenchymal transition (EMT). Lamin B1 associates with actively expressed and open euchromatin regions, forming dynamic euchromatin lamin B1-associated domains (eLADs) of about 0.3 Mb. Hi-C data link eLADs to the 3D organization of the mouse genome during EMT and correlate lamin B1 enrichment at topologically associating domain (TAD) borders with increased border strength. Having reduced levels of lamin B1 alters the EMT transcriptional signature and compromises the acquisition of mesenchymal traits. Thus, during EMT, the process of genome reorganization in mouse involves dynamic changes in eLADs.
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Affiliation(s)
| | - Enrique Blanco
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona, Spain
| | - Silvia Galan
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona, Spain
- Structural Genomic Group, CNAG-CRG, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Baldiri Reixac 4, Barcelona, Spain
| | - François Le Dily
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona, Spain
- Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra (UPF), 08003, Barcelona, Spain
| | - Yasmina Cuartero
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona, Spain
- Structural Genomic Group, CNAG-CRG, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Baldiri Reixac 4, Barcelona, Spain
| | - Gemma Serra-Bardenys
- Vall d'Hebron Institute of Oncology, 08035, Barcelona, Spain
- Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra (UPF), 08003, Barcelona, Spain
| | - Valerio Di Carlo
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona, Spain
| | - Ane Iturbide
- Institute of Epigenetics and Stem Cells, D-81377, München, Germany
| | | | - Lara Nonell
- Servei d'Anàlisi de Microarrays Institut Hospital del Mar d'Investigacions Mèdiques, Barcelona, Spain
| | - Antonio García de Herreros
- Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra (UPF), 08003, Barcelona, Spain
- Programa de Recerca en Càncer, Institut Hospital del Mar d'Investigacions Mèdiques, Barcelona, Spain
| | - Luciano Di Croce
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona, Spain
- ICREA, Pg. Lluis Companys 23, Barcelona, Spain
| | - Marc A Marti-Renom
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona, Spain
- Structural Genomic Group, CNAG-CRG, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Baldiri Reixac 4, Barcelona, Spain
- Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra (UPF), 08003, Barcelona, Spain
- ICREA, Pg. Lluis Companys 23, Barcelona, Spain
| | - Sandra Peiró
- Vall d'Hebron Institute of Oncology, 08035, Barcelona, Spain.
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125
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Actin-Based Cell Protrusion in a 3D Matrix. Trends Cell Biol 2018; 28:823-834. [PMID: 29970282 PMCID: PMC6158345 DOI: 10.1016/j.tcb.2018.06.003] [Citation(s) in RCA: 101] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 06/01/2018] [Accepted: 06/11/2018] [Indexed: 12/20/2022]
Abstract
Cell migration controls developmental processes (gastrulation and tissue patterning), tissue homeostasis (wound repair and inflammatory responses), and the pathobiology of diseases (cancer metastasis and inflammation). Understanding how cells move in physiologically relevant environments is of major importance, and the molecular machinery behind cell movement has been well studied on 2D substrates, beginning over half a century ago. Studies over the past decade have begun to reveal the mechanisms that control cell motility within 3D microenvironments – some similar to, and some highly divergent from those found in 2D. In this review we focus on migration and invasion of cells powered by actin, including formation of actin-rich protrusions at the leading edge, and the mechanisms that control nuclear movement in cells moving in a 3D matrix. Cell migration has been well studied in 2D, but how this relates to movement in physiological 3D tissues and matrix is not clear, particularly in vertebrate interstitial matrix. In 3D matrix cells actin polymerisation directly contributes to the formation of lamellipodia to facilitate migration and invasion (mesenchymal movement), analogous to 2D migration; actomyosin contractility promotes bleb formation to indirectly promote protrusion (amoeboid movement). Mesenchymal migration can be characterised by polymerisation of actin to form filopodial protrusions, in the absence of lamellipodia. Translocation of the nucleus is emerging as a critical step due to the constrictive environment of 3D matrices, and the mechanisms that transmit force to the nucleus and allow movement are beginning to be uncovered.
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126
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Robert A, Tian P, Adam SA, Kittisopikul M, Jaqaman K, Goldman RD, Gelfand VI. Kinesin-dependent transport of keratin filaments: a unified mechanism for intermediate filament transport. FASEB J 2018; 33:388-399. [PMID: 29944446 PMCID: PMC6355078 DOI: 10.1096/fj.201800604r] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Keratin intermediate filaments (IFs) are the major cytoskeletal component in epithelial cells. The dynamics of keratin IFs have been described to depend mostly on the actin cytoskeleton, but the rapid transport of fully polymerized keratin filaments has not been reported. In this work, we used a combination of photoconversion experiments and clustered regularly interspaced short palindromic repeats/clustered regularly interspaced short palindromic repeats-associated protein 9 genome editing to study the role of microtubules and microtubule motors in keratin filament transport. We found that long keratin filaments, like other types of IFs, are transported along microtubules by kinesin-1. Our data revealed that keratin and vimentin are nonconventional kinesin-1 cargoes because their transport did not require kinesin light chains, which are a typical adapter for kinesin-dependent cargo transport. Furthermore, we found that the same domain of the kinesin heavy chain tail is involved in keratin and vimentin IF transport, strongly suggesting that multiple types of IFs move along microtubules using an identical mechanism.-Robert, A., Tian, P., Adam, S. A., Kittisopikul, M., Jaqaman, K., Goldman, R. D., Gelfand, V. I. Kinesin-dependent transport of keratin filaments: a unified mechanism for intermediate filament transport.
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Affiliation(s)
- Amélie Robert
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Peirun Tian
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Stephen A Adam
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Mark Kittisopikul
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.,Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas, USA; and
| | - Khuloud Jaqaman
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas, USA; and.,Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Robert D Goldman
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Vladimir I Gelfand
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
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127
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Pradhan R, Ranade D, Sengupta K. Emerin modulates spatial organization of chromosome territories in cells on softer matrices. Nucleic Acids Res 2018; 46:5561-5586. [PMID: 29684168 PMCID: PMC6009696 DOI: 10.1093/nar/gky288] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 04/04/2018] [Accepted: 04/06/2018] [Indexed: 02/06/2023] Open
Abstract
Cells perceive and relay external mechanical forces into the nucleus through the nuclear envelope. Here we examined the effect of lowering substrate stiffness as a paradigm to address the impact of altered mechanical forces on nuclear structure-function relationships. RNA sequencing of cells on softer matrices revealed significant transcriptional imbalances, predominantly in chromatin associated processes and transcriptional deregulation of human Chromosome 1. Furthermore, 3-Dimensional fluorescence in situ hybridization (3D-FISH) analyses showed a significant mislocalization of Chromosome 1 and 19 Territories (CT) into the nuclear interior, consistent with their transcriptional deregulation. However, CT18 with relatively lower transcriptional dysregulation, also mislocalized into the nuclear interior. Furthermore, nuclear Lamins that regulate chromosome positioning, were mislocalized into the nuclear interior in response to lowered matrix stiffness. Notably, Lamin B2 overexpression retained CT18 near the nuclear periphery in cells on softer matrices. While, cells on softer matrices also activated emerin phosphorylation at a novel Tyr99 residue, the inhibition of which in a phospho-deficient mutant (emerinY99F), selectively retained chromosome 18 and 19 but not chromosome 1 territories at their conserved nuclear locations. Taken together, emerin functions as a key mechanosensor, that modulates the spatial organization of chromosome territories in the interphase nucleus.
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Affiliation(s)
- Roopali Pradhan
- Biology, Main Building, First Floor, Room#B-216, Indian Institute of Science Education and Research (IISER), Pune, Dr Homi Bhabha Road, Pashan, Pune 411008, Maharashtra, India
| | - Devika Ranade
- Biology, Main Building, First Floor, Room#B-216, Indian Institute of Science Education and Research (IISER), Pune, Dr Homi Bhabha Road, Pashan, Pune 411008, Maharashtra, India
| | - Kundan Sengupta
- Biology, Main Building, First Floor, Room#B-216, Indian Institute of Science Education and Research (IISER), Pune, Dr Homi Bhabha Road, Pashan, Pune 411008, Maharashtra, India
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128
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Insight into the functional organization of nuclear lamins in health and disease. Curr Opin Cell Biol 2018; 54:72-79. [PMID: 29800922 DOI: 10.1016/j.ceb.2018.05.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 04/24/2018] [Accepted: 05/08/2018] [Indexed: 11/20/2022]
Abstract
Lamins are the main component of the nuclear lamina, a protein meshwork at the inner nuclear membrane which primarily provide mechanical stability to the nucleus. Lamins, type V intermediate filament proteins, are also involved in many nuclear activities. Structural analysis of nuclei revealed that lamins form 3.5nm thick filaments often interact with nuclear pore complexes. Mutations in the LMNA gene, encoding A-type lamins, have been associated with at least 15 distinct diseases collectively termed laminopathies, including muscle, metabolic and neurological disorders, and premature aging syndrome. It is unclear how laminopathic mutations lead to such a wide array of diseases, essentially affecting almost all tissues.
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129
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Simon DN, Wriston A, Fan Q, Shabanowitz J, Florwick A, Dharmaraj T, Peterson SB, Gruenbaum Y, Carlson CR, Grønning-Wang LM, Hunt DF, Wilson KL. OGT ( O-GlcNAc Transferase) Selectively Modifies Multiple Residues Unique to Lamin A. Cells 2018; 7:E44. [PMID: 29772801 PMCID: PMC5981268 DOI: 10.3390/cells7050044] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 05/11/2018] [Accepted: 05/14/2018] [Indexed: 12/31/2022] Open
Abstract
The LMNA gene encodes lamins A and C with key roles in nuclear structure, signaling, gene regulation, and genome integrity. Mutations in LMNA cause over 12 diseases ('laminopathies'). Lamins A and C are identical for their first 566 residues. However, they form separate filaments in vivo, with apparently distinct roles. We report that lamin A is β-O-linked N-acetylglucosamine-(O-GlcNAc)-modified in human hepatoma (Huh7) cells and in mouse liver. In vitro assays with purified O-GlcNAc transferase (OGT) enzyme showed robust O-GlcNAcylation of recombinant mature lamin A tails (residues 385⁻646), with no detectable modification of lamin B1, lamin C, or 'progerin' (Δ50) tails. Using mass spectrometry, we identified 11 O-GlcNAc sites in a 'sweet spot' unique to lamin A, with up to seven sugars per peptide. Most sites were unpredicted by current algorithms. Double-mutant (S612A/T643A) lamin A tails were still robustly O-GlcNAc-modified at seven sites. By contrast, O-GlcNAcylation was undetectable on tails bearing deletion Δ50, which causes Hutchinson⁻Gilford progeria syndrome, and greatly reduced by deletion Δ35. We conclude that residues deleted in progeria are required for substrate recognition and/or modification by OGT in vitro. Interestingly, deletion Δ35, which does not remove the majority of identified O-GlcNAc sites, does remove potential OGT-association motifs (lamin A residues 622⁻625 and 639⁻645) homologous to that in mouse Tet1. These biochemical results are significant because they identify a novel molecular pathway that may profoundly influence lamin A function. The hypothesis that lamin A is selectively regulated by OGT warrants future testing in vivo, along with two predictions: genetic variants may contribute to disease by perturbing OGT-dependent regulation, and nutrient or other stresses might cause OGT to misregulate wildtype lamin A.
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Affiliation(s)
- Dan N Simon
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA.
| | - Amanda Wriston
- Department of Chemistry, University of Virginia, Charlottesville, VA 22904, USA.
| | - Qiong Fan
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, 0317 Oslo, Norway.
| | - Jeffrey Shabanowitz
- Department of Chemistry, University of Virginia, Charlottesville, VA 22904, USA.
| | - Alyssa Florwick
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA.
| | - Tejas Dharmaraj
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA.
| | - Sherket B Peterson
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Yosef Gruenbaum
- Department of Genetics, Institute of Life Sciences, Hebrew University of Jerusalem, Givat Ram Jerusalem 91904, Israel.
| | - Cathrine R Carlson
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, 0450 Oslo, Norway.
| | - Line M Grønning-Wang
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, 0317 Oslo, Norway.
| | - Donald F Hunt
- Department of Chemistry, University of Virginia, Charlottesville, VA 22904, USA.
- Department of Pathology, University of Virginia, Charlottesville, VA 22904, USA.
| | - Katherine L Wilson
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA.
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130
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Cho S, Abbas A, Irianto J, Ivanovska IL, Xia Y, Tewari M, Discher DE. Progerin phosphorylation in interphase is lower and less mechanosensitive than lamin-A,C in iPS-derived mesenchymal stem cells. Nucleus 2018; 9:230-245. [PMID: 29619860 PMCID: PMC5973135 DOI: 10.1080/19491034.2018.1460185] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Interphase phosphorylation of lamin-A,C depends dynamically on a cell's microenvironment, including the stiffness of extracellular matrix. However, phosphorylation dynamics is poorly understood for diseased forms such as progerin, a permanently farnesylated mutant of LMNA that accelerates aging of stiff and mechanically stressed tissues. Here, fine-excision alignment mass spectrometry (FEA-MS) is developed to quantify progerin and its phosphorylation levels in patient iPS cells differentiated to mesenchymal stem cells (MSCs). The stoichiometry of total A-type lamins (including progerin) versus B-type lamins measured for Progeria iPS-MSCs prove similar to that of normal MSCs, with total A-type lamins more abundant than B-type lamins. However, progerin behaves more like farnesylated B-type lamins in mechanically-induced segregation from nuclear blebs. Phosphorylation of progerin at multiple sites in iPS-MSCs cultured on rigid plastic is also lower than that of normal lamin-A and C. Reduction of nuclear tension upon i) cell rounding/detachment from plastic, ii) culture on soft gels, and iii) inhibition of actomyosin stress increases phosphorylation and degradation of lamin-C > lamin-A > progerin. Such mechano-sensitivity diminishes, however, with passage as progerin and DNA damage accumulate. Lastly, transcription-regulating retinoids exert equal effects on both diseased and normal A-type lamins, suggesting a differential mechano-responsiveness might best explain the stiff tissue defects in Progeria.
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Affiliation(s)
- Sangkyun Cho
- Molecular & Cell Biophysics Lab, University of Pennsylvania, Philadelphia, PA, USA
| | - Amal Abbas
- Molecular & Cell Biophysics Lab, University of Pennsylvania, Philadelphia, PA, USA
| | - Jerome Irianto
- Molecular & Cell Biophysics Lab, University of Pennsylvania, Philadelphia, PA, USA
| | - Irena L. Ivanovska
- Molecular & Cell Biophysics Lab, University of Pennsylvania, Philadelphia, PA, USA
| | - Yuntao Xia
- Molecular & Cell Biophysics Lab, University of Pennsylvania, Philadelphia, PA, USA
| | - Manu Tewari
- Molecular & Cell Biophysics Lab, University of Pennsylvania, Philadelphia, PA, USA
| | - Dennis E. Discher
- Molecular & Cell Biophysics Lab, University of Pennsylvania, Philadelphia, PA, USA,CONTACT Dennis E. Discher , University of Pennsylvania, 129 Towne Bldg, Philadelphia, PA 19104
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131
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Penfield L, Wysolmerski B, Mauro M, Farhadifar R, Martinez MA, Biggs R, Wu HY, Broberg C, Needleman D, Bahmanyar S. Dynein pulling forces counteract lamin-mediated nuclear stability during nuclear envelope repair. Mol Biol Cell 2018; 29:852-868. [PMID: 29386297 PMCID: PMC5905298 DOI: 10.1091/mbc.e17-06-0374] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Transient nuclear envelope (NE) ruptures in the Caenorhabditis elegans zygote are caused by a weakened nuclear lamina during nuclear positioning. Dynein-pulling forces enhance the severity of ruptures, while lamin restricts nucleocytoplasmic mixing and allows stable NE repair. This work is the first mechanistic analysis of NE rupture and repair in an organism. Recent work done exclusively in tissue culture cells revealed that the nuclear envelope (NE) ruptures and repairs in interphase. The duration of NE ruptures depends on lamins; however, the underlying mechanisms and relevance to in vivo events are not known. Here, we use the Caenorhabditis elegans zygote to analyze lamin’s role in NE rupture and repair in vivo. Transient NE ruptures and subsequent NE collapse are induced by weaknesses in the nuclear lamina caused by expression of an engineered hypomorphic C. elegans lamin allele. Dynein-generated forces that position nuclei enhance the severity of transient NE ruptures and cause NE collapse. Reduction of dynein forces allows the weakened lamin network to restrict nucleo–cytoplasmic mixing and support stable NE recovery. Surprisingly, the high incidence of transient NE ruptures does not contribute to embryonic lethality, which is instead correlated with stochastic chromosome scattering resulting from premature NE collapse, suggesting that C. elegans tolerates transient losses of NE compartmentalization during early embryogenesis. In sum, we demonstrate that lamin counteracts dynein forces to promote stable NE repair and prevent catastrophic NE collapse, and thus provide the first mechanistic analysis of NE rupture and repair in an organismal context.
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Affiliation(s)
- Lauren Penfield
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520
| | - Brian Wysolmerski
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520
| | - Michael Mauro
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520
| | - Reza Farhadifar
- Department of Molecular and Cellular Biology, School of Engineering and Applied Sciences, FAS Center for Systems Biology, Harvard University, Cambridge, MA 02138
| | - Michael A Martinez
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520
| | - Ronald Biggs
- Department of Cellular & Molecular Medicine, Ludwig Institute for Cancer Research, University of California, San Diego, La Jolla, CA 92093
| | - Hai-Yin Wu
- Department of Molecular and Cellular Biology, School of Engineering and Applied Sciences, FAS Center for Systems Biology, Harvard University, Cambridge, MA 02138
| | - Curtis Broberg
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520
| | - Daniel Needleman
- Department of Molecular and Cellular Biology, School of Engineering and Applied Sciences, FAS Center for Systems Biology, Harvard University, Cambridge, MA 02138
| | - Shirin Bahmanyar
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520
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132
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Stephens AD, Liu PZ, Banigan EJ, Almassalha LM, Backman V, Adam SA, Goldman RD, Marko JF. Chromatin histone modifications and rigidity affect nuclear morphology independent of lamins. Mol Biol Cell 2018; 29:220-233. [PMID: 29142071 PMCID: PMC5909933 DOI: 10.1091/mbc.e17-06-0410] [Citation(s) in RCA: 206] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 10/17/2017] [Accepted: 11/08/2017] [Indexed: 01/29/2023] Open
Abstract
Nuclear shape and architecture influence gene localization, mechanotransduction, transcription, and cell function. Abnormal nuclear morphology and protrusions termed "blebs" are diagnostic markers for many human afflictions including heart disease, aging, progeria, and cancer. Nuclear blebs are associated with both lamin and chromatin alterations. A number of prior studies suggest that lamins dictate nuclear morphology, but the contributions of altered chromatin compaction remain unclear. We show that chromatin histone modification state dictates nuclear rigidity, and modulating it is sufficient to both induce and suppress nuclear blebs. Treatment of mammalian cells with histone deacetylase inhibitors to increase euchromatin or histone methyltransferase inhibitors to decrease heterochromatin results in a softer nucleus and nuclear blebbing, without perturbing lamins. Conversely, treatment with histone demethylase inhibitors increases heterochromatin and chromatin nuclear rigidity, which results in reduced nuclear blebbing in lamin B1 null nuclei. Notably, increased heterochromatin also rescues nuclear morphology in a model cell line for the accelerated aging disease Hutchinson-Gilford progeria syndrome caused by mutant lamin A, as well as cells from patients with the disease. Thus, chromatin histone modification state is a major determinant of nuclear blebbing and morphology via its contribution to nuclear rigidity.
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Affiliation(s)
- Andrew D Stephens
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208
| | - Patrick Z Liu
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208
| | - Edward J Banigan
- Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208.,Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Luay M Almassalha
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208
| | - Vadim Backman
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208
| | - Stephen A Adam
- Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611
| | - Robert D Goldman
- Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611
| | - John F Marko
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208.,Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208
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133
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Gerace L, Tapia O. Messages from the voices within: regulation of signaling by proteins of the nuclear lamina. Curr Opin Cell Biol 2018; 52:14-21. [PMID: 29306725 DOI: 10.1016/j.ceb.2017.12.009] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Accepted: 12/14/2017] [Indexed: 12/30/2022]
Abstract
The nuclear lamina (NL) is a protein scaffold lining the nuclear envelope that consists of nuclear lamins and associated transmembrane proteins. It helps to organize the nuclear envelope, chromosomes, and the cytoplasmic cytoskeleton. The NL also has an important role in regulation of signaling, as highlighted by the wide range of human diseases caused by mutations in the genes for NL proteins with associated signaling defects. This review will consider diverse mechanisms for signaling regulation by the NL that have been uncovered recently, including interaction with signaling effectors, modulation of actin assembly and compositional alteration of the NL. Cells with discrete NL mutations often show disruption of multiple signaling pathways, however, and for the most part the mechanistic basis for these complex phenotypes remains to be elucidated.
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Affiliation(s)
- Larry Gerace
- Department of Molecular Medicine, The Scripps Research Institute, 10550 N Torrey Pines Rd, La Jolla, CA 92037, United States.
| | - Olga Tapia
- Department of Molecular Medicine, The Scripps Research Institute, 10550 N Torrey Pines Rd, La Jolla, CA 92037, United States; Department of Anatomy and Cell Biology and CIBERNED, University of Cantabria-IDIVAL, Cardenal H Oria s/n, 39011 Santander, Spain
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134
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Houthaeve G, Robijns J, Braeckmans K, De Vos WH. Bypassing Border Control: Nuclear Envelope Rupture in Disease. Physiology (Bethesda) 2018; 33:39-49. [DOI: 10.1152/physiol.00029.2017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 10/31/2017] [Accepted: 10/31/2017] [Indexed: 11/22/2022] Open
Abstract
Recent observations in laminopathy patient cells and cancer cells have revealed that the nuclear envelope (NE) can transiently rupture during interphase. NE rupture leads to an uncoordinated exchange of nuclear and cytoplasmic material, thereby deregulating cellular homeostasis. Moreover, concurrently inflicted DNA damage could prime rupture-prone cells for genome instability. Thus, NE rupture may represent a novel pathogenic mechanism that has far-reaching consequences for cell and organism physiology.
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Affiliation(s)
- Gaëlle Houthaeve
- Department of Veterinary Sciences, Laboratory of Cell Biology and Histology, University of Antwerp, Antwerp, Belgium
- Laboratory of General Biochemistry and Physical Pharmacy, Ghent University, Ghent, Belgium
| | - Joke Robijns
- Department of Veterinary Sciences, Laboratory of Cell Biology and Histology, University of Antwerp, Antwerp, Belgium
| | - Kevin Braeckmans
- Laboratory of General Biochemistry and Physical Pharmacy, Ghent University, Ghent, Belgium
- Centre for Nano- and Biophotonics, Ghent University, Ghent, Belgium
| | - Winnok H. De Vos
- Department of Veterinary Sciences, Laboratory of Cell Biology and Histology, University of Antwerp, Antwerp, Belgium
- Department of Molecular Biotechnology, Cell Systems and Imaging Research Group (CSI), Ghent University, Ghent, Belgium
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135
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Sen Gupta A, Sengupta K. Lamin B2 Modulates Nucleolar Morphology, Dynamics, and Function. Mol Cell Biol 2017; 37:e00274-17. [PMID: 28993479 PMCID: PMC5705821 DOI: 10.1128/mcb.00274-17] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 07/05/2017] [Accepted: 09/29/2017] [Indexed: 01/11/2023] Open
Abstract
The nucleolus is required for ribosome biogenesis. Human cells have 2 or 3 nucleoli associated with nucleolar organizer region (NOR)-bearing chromosomes. An increase in number and altered nucleolar morphology define cancer cells. However, the mechanisms that modulate nucleolar morphology and function are unclear. Here we show that in addition to localizing at the nuclear envelope, lamin B2 localizes proximal to nucleolin at the granular component (GC) of the nucleolus and associates with the nucleolar proteins nucleolin and nucleophosmin. Lamin B2 knockdown severely disrupted the nucleolar morphology, which was rescued to intact and discrete nucleoli upon lamin B2 overexpression. Furthermore, two mutually exclusive lamin B2 deletion mutants, ΔHead and ΔSLS, rescued nuclear and nucleolar morphology defects, respectively, induced upon lamin B2 depletion, suggesting independent roles for lamin B2 at the nucleolus and nuclear envelope. Lamin B2 depletion increased nucleolin aggregation in the nucleoplasm, implicating lamin B2 in stabilizing nucleolin within the nucleolus. Lamin B2 knockdown upregulated nucleolus-specific 45S rRNA and upstream intergenic sequence (IGS) transcripts. The IGS transcripts colocalized with aggregates of nucleolin speckles, which were sustained in the nucleoplasm upon lamin B2 depletion. Taken together, these studies uncover a novel role for lamin B2 in modulating the morphology, dynamics, and function of the nucleolus.
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Affiliation(s)
- Ayantika Sen Gupta
- Biology, Indian Institute of Science Education and Research, Pune, India
| | - Kundan Sengupta
- Biology, Indian Institute of Science Education and Research, Pune, India
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136
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Banigan EJ, Stephens AD, Marko JF. Mechanics and Buckling of Biopolymeric Shells and Cell Nuclei. Biophys J 2017; 113:1654-1663. [PMID: 29045860 DOI: 10.1016/j.bpj.2017.08.034] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 08/08/2017] [Accepted: 08/22/2017] [Indexed: 12/31/2022] Open
Abstract
We study a Brownian dynamics simulation model of a biopolymeric shell deformed by axial forces exerted at opposing poles. The model exhibits two distinct, linear force-extension regimes, with the response to small tensions governed by linear elasticity and the response to large tensions governed by an effective spring constant that scales with radius as R-0.25. When extended beyond the initial linear elastic regime, the shell undergoes a hysteretic, temperature-dependent buckling transition. We experimentally observe this buckling transition by stretching and imaging the lamina of isolated cell nuclei. Furthermore, the interior contents of the shell can alter mechanical response and buckling, which we show by simulating a model for the nucleus that quantitatively agrees with our micromanipulation experiments stretching individual nuclei.
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Affiliation(s)
- Edward J Banigan
- Department of Physics and Astronomy, Northwestern University, Evanston, Illinois.
| | - Andrew D Stephens
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois
| | - John F Marko
- Department of Physics and Astronomy, Northwestern University, Evanston, Illinois; Department of Molecular Biosciences, Northwestern University, Evanston, Illinois
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137
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Bhattacharjee P, Dasgupta D, Sengupta K. DCM associated LMNA mutations cause distortions in lamina structure and assembly. Biochim Biophys Acta Gen Subj 2017; 1861:2598-2608. [PMID: 28844980 DOI: 10.1016/j.bbagen.2017.08.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 08/01/2017] [Accepted: 08/11/2017] [Indexed: 11/22/2022]
Abstract
BACKGROUND A and B-type lamins are integral scaffolding components of the nuclear lamina which impart rigidity and shape to all metazoan nuclei. Over 450 mutations in A-type lamins are associated with 16 human diseases including dilated cardiomyopathy (DCM). Here, we show that DCM mutants perturb the self-association of lamin A (LA) and it's binding with lamin B1 (LB1). METHODS We used confocal and superresolution microscopy (NSIM) to study the effect of LA mutants on the nuclear lamina. We further used circular dichroism, fluorescence spectroscopy and isothermal titration calorimetry (ITC) to probe the structural modulations, self-association and heteropolymeric association of mutant LA. RESULTS Transfection of mutants in cultured cell lines result in the formation of nuclear aggregates of varied size and distribution. Endogenous LB1 is sequestered into these aggregates. This is consistent with the ten-fold increase in association constant of the mutant proteins compared to the wild type. These mutants exhibit differential heterotypic interaction with LB1, along with significant secondary and tertiary structural alterations of the interacting proteins. Thermodynamic studies demonstrate that the mutants bind to LB1 with different stoichiometry, affinity and energetics. CONCLUSIONS In this report we show that increased self-association propensity of mutant LA modulates the LA-LB1 interaction and precludes the formation of an otherwise uniform laminar network. GENERAL SIGNIFICANCE Our results might highlight the role of homotypic and heterotypic interactions of LA in the pathogenesis of DCM and hence laminopathies in the broader sense.
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Affiliation(s)
- Pritha Bhattacharjee
- Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064, India
| | - Dipak Dasgupta
- Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064, India.
| | - Kaushik Sengupta
- Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064, India.
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138
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Serebryannyy L, Misteli T. Protein sequestration at the nuclear periphery as a potential regulatory mechanism in premature aging. J Cell Biol 2017; 217:21-37. [PMID: 29051264 PMCID: PMC5748986 DOI: 10.1083/jcb.201706061] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 08/10/2017] [Accepted: 08/17/2017] [Indexed: 12/19/2022] Open
Abstract
Serebryannyy and Misteli provide a perspective on how protein sequestration at the inner nuclear membrane and nuclear lamina might influence aging. Despite the extensive description of numerous molecular changes associated with aging, insights into the driver mechanisms of this fundamental biological process are limited. Based on observations in the premature aging syndrome Hutchinson–Gilford progeria, we explore the possibility that protein regulation at the inner nuclear membrane and the nuclear lamina contributes to the aging process. In support, sequestration of nucleoplasmic proteins to the periphery impacts cell stemness, the response to cytotoxicity, proliferation, changes in chromatin state, and telomere stability. These observations point to the nuclear periphery as a central regulator of the aging phenotype.
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Affiliation(s)
| | - Tom Misteli
- National Cancer Institute, National Institutes of Health, Bethesda, MD
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139
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Pecorari I, Borin D, Sbaizero O. A Perspective on the Experimental Techniques for Studying Lamins. Cells 2017; 6:E33. [PMID: 28994747 PMCID: PMC5755493 DOI: 10.3390/cells6040033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 10/01/2017] [Accepted: 10/05/2017] [Indexed: 01/29/2023] Open
Abstract
Lamins are type V intermediate filaments that collectively form a meshwork underneath the inner nuclear membrane, called nuclear lamina. Furthermore, they are also present in the nucleoplasm. Lamins are experiencing a growing interest, since a wide range of diseases are induced by mutations in the gene coding for A-type lamins, globally known as laminopathies. Moreover, it has been demonstrated that lamins are involved in other pathological conditions, like cancer. The role of lamins has been studied from several perspectives, exploiting different techniques and procedures. This multidisciplinary approach has contributed to resolving the unique features of lamins and has provided a thorough insight in their role in living organisms. Yet, there are still many unanswered questions, which constantly generate research in the field. The present work is aimed to review some interesting experimental techniques performed so far to study lamins. Scientists can take advantage of this collection for their novel investigations, being aware of the already pursued and consolidated methodologies. Hopefully, advances in these research directions will provide insights to achieve better diagnostic procedures and effective therapeutic options.
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Affiliation(s)
- Ilaria Pecorari
- Department of Engineering and Architecture, University of Trieste, Via Valerio 10, 34127 Trieste, Italy.
| | - Daniele Borin
- Department of Engineering and Architecture, University of Trieste, Via Valerio 10, 34127 Trieste, Italy.
| | - Orfeo Sbaizero
- Department of Engineering and Architecture, University of Trieste, Via Valerio 10, 34127 Trieste, Italy.
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140
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de Leeuw R, Gruenbaum Y, Medalia O. Nuclear Lamins: Thin Filaments with Major Functions. Trends Cell Biol 2017; 28:34-45. [PMID: 28893461 DOI: 10.1016/j.tcb.2017.08.004] [Citation(s) in RCA: 196] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 08/08/2017] [Accepted: 08/14/2017] [Indexed: 10/18/2022]
Abstract
The nuclear lamina is a nuclear peripheral meshwork that is mainly composed of nuclear lamins, although a small fraction of lamins also localizes throughout the nucleoplasm. Lamins are classified as type V intermediate filament (IF) proteins. Mutations in lamin genes cause at least 15 distinct human diseases, collectively termed laminopathies, including muscle, metabolic, and neuronal diseases, and can cause accelerated aging. Most of these mutations are in the LMNA gene encoding A-type lamins. A growing number of nuclear proteins are known to bind lamins and are implicated in both nuclear and cytoskeletal organization, mechanical stability, chromatin organization, signaling, gene regulation, genome stability, and cell differentiation. Recent studies reveal the organization of the lamin filament meshwork in somatic cells where they assemble as tetramers in cross-section of the filaments.
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Affiliation(s)
- Rebecca de Leeuw
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Yosef Gruenbaum
- Department of Genetics, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Ohad Medalia
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland; Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University, Beer-Sheva 84105, Israel.
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141
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Sardo L, Lin A, Khakhina S, Beckman L, Ricon L, Elbezanti W, Jaison T, Vishwasrao H, Shroff H, Janetopoulos C, Klase ZA. Real-time visualization of chromatin modification in isolated nuclei. J Cell Sci 2017; 130:2926-2940. [PMID: 28743737 PMCID: PMC5612227 DOI: 10.1242/jcs.205823] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 07/13/2017] [Indexed: 12/31/2022] Open
Abstract
Chromatin modification is traditionally assessed in biochemical assays that provide average measurements of static events given that the analysis requires components from many cells. Microscopy can visualize single cells, but the cell body and organelles can hamper staining and visualization of the nucleus. Normally, chromatin is visualized by immunostaining a fixed sample or by expressing exogenous fluorescently tagged proteins in a live cell. Alternative microscopy tools to observe changes of endogenous chromatin in real-time are needed. Here, we isolated transcriptionally competent nuclei from cells and used antibody staining without fixation to visualize changes in endogenous chromatin. This method allows the real-time addition of drugs and fluorescent probes to one or more nuclei while under microscopy observation. A high-resolution map of 11 endogenous nuclear markers of the histone code, transcription machinery and architecture was obtained in transcriptionally active nuclei by performing confocal and structured illumination microscopy. We detected changes in chromatin modification and localization at the single-nucleus level after inhibition of histone deacetylation. Applications in the study of RNA transcription, viral protein function and nuclear architecture are presented. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Luca Sardo
- Department of Biological Sciences, McNeil Science and Technology Center, University of the Sciences, 600 S 43rd Street, Philadelphia, PA 19104, USA
| | - Angel Lin
- Department of Biological Sciences, McNeil Science and Technology Center, University of the Sciences, 600 S 43rd Street, Philadelphia, PA 19104, USA
| | - Svetlana Khakhina
- Department of Biological Sciences, McNeil Science and Technology Center, University of the Sciences, 600 S 43rd Street, Philadelphia, PA 19104, USA
| | - Lucas Beckman
- Department of Biological Sciences, McNeil Science and Technology Center, University of the Sciences, 600 S 43rd Street, Philadelphia, PA 19104, USA
| | - Luis Ricon
- Department of Biological Sciences, McNeil Science and Technology Center, University of the Sciences, 600 S 43rd Street, Philadelphia, PA 19104, USA
| | - Weam Elbezanti
- Department of Biological Sciences, McNeil Science and Technology Center, University of the Sciences, 600 S 43rd Street, Philadelphia, PA 19104, USA
| | - Tara Jaison
- Department of Biological Sciences, McNeil Science and Technology Center, University of the Sciences, 600 S 43rd Street, Philadelphia, PA 19104, USA
| | - Harshad Vishwasrao
- Advanced Imaging and Microscopy Resource, National Institutes of Health, Bethesda, MD 28092, USA
| | - Hari Shroff
- Section on High Resolution Optical Imaging, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 28092, USA
| | - Christopher Janetopoulos
- Department of Biological Sciences, McNeil Science and Technology Center, University of the Sciences, 600 S 43rd Street, Philadelphia, PA 19104, USA
| | - Zachary A Klase
- Department of Biological Sciences, McNeil Science and Technology Center, University of the Sciences, 600 S 43rd Street, Philadelphia, PA 19104, USA
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142
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Fal K, Asnacios A, Chabouté ME, Hamant O. Nuclear envelope: a new frontier in plant mechanosensing? Biophys Rev 2017; 9:389-403. [PMID: 28801801 PMCID: PMC5578935 DOI: 10.1007/s12551-017-0302-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 07/28/2017] [Indexed: 02/07/2023] Open
Abstract
In animals, it is now well established that forces applied at the cell surface are propagated through the cytoskeleton to the nucleus, leading to deformations of the nuclear structure and, potentially, to modification of gene expression. Consistently, altered nuclear mechanics has been related to many genetic disorders, such as muscular dystrophy, cardiomyopathy and progeria. In plants, the integration of mechanical signals in cell and developmental biology has also made great progress. Yet, while the link between cell wall stresses and cytoskeleton is consolidated, such cortical mechanical cues have not been integrated with the nucleoskeleton. Here, we propose to take inspiration from studies on animal nuclei to identify relevant methods amenable to probing nucleus mechanics and deformation in plant cells, with a focus on microrheology. To identify potential molecular targets, we also compare the players at the nuclear envelope, namely lamina and LINC complex, in both plant and animal nuclei. Understanding how mechanical signals are transduced to the nucleus across kingdoms will likely have essential implications in development (e.g. how mechanical cues add robustness to gene expression patterns), in the nucleoskeleton-cytoskeleton nexus (e.g. how stress is propagated in turgid/walled cells), as well as in transcriptional control, chromatin biology and epigenetics.
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Affiliation(s)
- Kateryna Fal
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, 69342, Lyon, France
| | - Atef Asnacios
- Laboratoire Matières et Systèmes Complexes, Université Paris-Diderot and CNRS, UMR 7057, Sorbonne Paris Cité, Paris, France
| | - Marie-Edith Chabouté
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, 67000, Strasbourg, France
| | - Olivier Hamant
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, 69342, Lyon, France.
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143
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Lamina-Associated Domains: Links with Chromosome Architecture, Heterochromatin, and Gene Repression. Cell 2017; 169:780-791. [PMID: 28525751 DOI: 10.1016/j.cell.2017.04.022] [Citation(s) in RCA: 628] [Impact Index Per Article: 89.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 04/11/2017] [Accepted: 04/14/2017] [Indexed: 01/06/2023]
Abstract
In metazoan cell nuclei, hundreds of large chromatin domains are in close contact with the nuclear lamina. Such lamina-associated domains (LADs) are thought to help organize chromosomes inside the nucleus and have been associated with gene repression. Here, we discuss the properties of LADs, the molecular mechanisms that determine their association with the nuclear lamina, their dynamic links with other nuclear compartments, and their proposed roles in gene regulation.
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144
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Schoen I, Aires L, Ries J, Vogel V. Nanoscale invaginations of the nuclear envelope: Shedding new light on wormholes with elusive function. Nucleus 2017; 8:506-514. [PMID: 28686487 DOI: 10.1080/19491034.2017.1337621] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Recent advances in fluorescence microscopy have opened up new possibilities to investigate chromosomal and nuclear 3D organization on the nanoscale. We here discuss their potential for elucidating topographical details of the nuclear lamina. Single molecule localization microscopy (SMLM) in combination with immunostainings of lamina proteins readily reveals tube-like invaginations with a diameter of 100-500 nm. Although these invaginations have been established as a frequent and general feature of interphase nuclei across different cell types, their formation mechanism and function have remained largely elusive. We critically review the current state of research, propose possible connections to lamina associated domains (LADs), and revisit the discussion about the potential role of these invaginations for accelerating mRNA nuclear export. Illustrative studies using 3D super-resolution imaging are shown and will be instrumental to decipher the physiological role of these nanoscale invaginations.
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Affiliation(s)
- Ingmar Schoen
- a ETH Zurich, Department of Health Sciences and Technology, Laboratory of Applied Mechanobiology , Zurich , Switzerland
| | - Lina Aires
- a ETH Zurich, Department of Health Sciences and Technology, Laboratory of Applied Mechanobiology , Zurich , Switzerland
| | - Jonas Ries
- b European Molecular Biology Laboratory, Cell Biology and Biophysics Unit , Heidelberg , Germany
| | - Viola Vogel
- a ETH Zurich, Department of Health Sciences and Technology, Laboratory of Applied Mechanobiology , Zurich , Switzerland
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145
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Abstract
Nuclear lamins are components of the peripheral lamina that define the mechanical properties of nuclei and tether heterochromatin to the periphery. A-type lamins localize also to the nuclear interior, but the regulation and specific functions of this nucleoplasmic lamin pool are poorly understood. In this Commentary, we summarize known pathways that are potentially involved in the localization and dynamic behavior of intranuclear lamins, including their post-translational modifications and interactions with nucleoplasmic proteins, such as lamina-associated polypeptide 2α (LAP2α; encoded by TMPO). In addition, new data suggest that lamins in the nuclear interior have an important role in chromatin regulation and gene expression through dynamic binding to both hetero- and euchromatic genomic regions and promoter subdomains, thereby affecting epigenetic pathways and chromatin accessibility. Nucleoplasmic lamins also have a role in spatial chromatin organization and may be involved in mechanosignaling. In view of this newly emerging concept, we propose that the previously reported cellular phenotypes in lamin-linked diseases are, at least in part, rooted in an impaired regulation and/or function of the nucleoplasmic lamin A/C pool.
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Affiliation(s)
- Nana Naetar
- Center of Medical Biochemistry, Max F. Perutz Laboratories (MFPL), Medical University of Vienna, Vienna Biocenter (VBC), Dr.-Bohr-Gasse 9, Vienna A-1030, Austria
| | - Simona Ferraioli
- Center of Medical Biochemistry, Max F. Perutz Laboratories (MFPL), Medical University of Vienna, Vienna Biocenter (VBC), Dr.-Bohr-Gasse 9, Vienna A-1030, Austria
| | - Roland Foisner
- Center of Medical Biochemistry, Max F. Perutz Laboratories (MFPL), Medical University of Vienna, Vienna Biocenter (VBC), Dr.-Bohr-Gasse 9, Vienna A-1030, Austria
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146
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Turgay Y, Medalia O. The structure of lamin filaments in somatic cells as revealed by cryo-electron tomography. Nucleus 2017. [PMID: 28635493 DOI: 10.1080/19491034.2017.1337622] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
Metazoan nuclei are equipped with nuclear lamina - a thin layer of intermediate filaments (IFs) mostly built of nuclear lamins facing the inner nuclear membrane (INM). The nuclear lamina serves as an interaction hub for INM-proteins, soluble nuclear factors and DNA. It confers structural and mechanical stability to the nucleus, transduces mechanical forces and biochemical signals across the nuclear envelope (NE) and regulates the organization of chromatin. By using cryo-electron tomography (cryo-ET), we recently provided an unprecedented view into the 3D organization of lamin filaments within the lamina meshwork in mammalian somatic cells. Through implementation of averaging procedures, we resolved the rod and globular Ig-fold domains of lamin filaments. The density maps suggested that they assemble into 3.5 nm thick filaments. Our analysis revealed interesting structural differences between nucleoplasmic and cytoplasmic intermediate filaments, raising the question of which molecular cues define their assembly modes inside the cell.
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Affiliation(s)
- Y Turgay
- a Department of Biochemistry , University of Zurich , Zurich , Switzerland
| | - O Medalia
- a Department of Biochemistry , University of Zurich , Zurich , Switzerland.,b Department of Life Sciences and the National Institute for Biotechnology in the Negev , Ben-Gurion University , Beer-Sheva , Israel
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147
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Athirasala A, Hirsch N, Buxboim A. Nuclear mechanotransduction: sensing the force from within. Curr Opin Cell Biol 2017. [PMID: 28641092 DOI: 10.1016/j.ceb.2017.04.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The cell nucleus is a hallmark of eukaryotic evolution, where gene expression is regulated and the genome is replicated and repaired. Yet, in addition to complex molecular processes, the nucleus has also evolved to serve physical tasks that utilize its optical and mechanical properties. Nuclear mechanotransduction of externally applied forces and extracellular stiffness is facilitated by the physical connectivity of the extracellular environment, the cytoskeleton and the nucleoskeletal matrix of lamins and chromatin. Nuclear mechanosensor elements convert applied tension into biochemical cues that activate downstream signal transduction pathways. Mechanoregulatory networks stabilize a contractile cell state with feedback to matrix, cell adhesions and cytoskeletal elements. Recent advances have thus provided mechanistic insights into how forces are sensed from within, that is, in the nucleus where cell-fate decision-making is performed.
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Affiliation(s)
- Avathamsa Athirasala
- Alexander Grass Center for Bioengineering, School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Nivi Hirsch
- Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Amnon Buxboim
- Alexander Grass Center for Bioengineering, School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel; Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel.
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148
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Fišerová J, Efenberková M, Sieger T, Maninová M, Uhlířová J, Hozák P. Chromatin organization at the nuclear periphery as revealed by image analysis of structured illumination microscopy data. J Cell Sci 2017; 130:2066-2077. [PMID: 28476938 DOI: 10.1242/jcs.198424] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 05/02/2017] [Indexed: 12/28/2022] Open
Abstract
The nuclear periphery (NP) plays a substantial role in chromatin organization. Heterochromatin at the NP is interspersed with active chromatin surrounding nuclear pore complexes (NPCs); however, details of the peripheral chromatin organization are missing. To discern the distribution of epigenetic marks at the NP of HeLa nuclei, we used structured illumination microscopy combined with a new MATLAB software tool for automatic NP and NPC detection, measurements of fluorescent intensity and statistical analysis of measured data. Our results show that marks for both active and non-active chromatin associate differentially with NPCs. The incidence of heterochromatin marks, such as H3K27me2 and H3K9me2, was significantly lower around NPCs. In contrast, the presence of marks of active chromatin such as H3K4me2 was only decreased very slightly around the NPCs or not at all (H3K9Ac). Interestingly, the histone demethylases LSD1 (also known as KDM1A) and KDM2A were enriched within the NPCs, suggesting that there was a chromatin-modifying mechanism at the NPCs. Inhibition of transcription resulted in a larger drop in the distribution of H1, H3K9me2 and H3K23me2, which implies that transcription has a role in the organization of heterochromatin at the NP.
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Affiliation(s)
- Jindřiška Fišerová
- Department of Biology of the Cell Nucleus, Institute of Molecular Genetics CAS, v.v.i., Vídeňská 1083, Prague 142 00, Czech Republic
| | - Michaela Efenberková
- Microscopy Centre - LM and EM, Institute of Molecular Genetics CAS, v.v.i., Vídeňská 1083, Prague 142 00, Czech Republic
| | - Tomáš Sieger
- Department of Cybernetics, Faculty of Electrical Engineering, Czech Technical University in Prague, Prague, 121 35, Czech Republic
| | - Miloslava Maninová
- Department of Biology of the Cell Nucleus, Institute of Molecular Genetics CAS, v.v.i., Vídeňská 1083, Prague 142 00, Czech Republic
| | - Jana Uhlířová
- Department of Biology of the Cell Nucleus, Institute of Molecular Genetics CAS, v.v.i., Vídeňská 1083, Prague 142 00, Czech Republic
| | - Pavel Hozák
- Department of Biology of the Cell Nucleus, Institute of Molecular Genetics CAS, v.v.i., Vídeňská 1083, Prague 142 00, Czech Republic.,Division BIOCEV, Institute of Molecular Genetics CAS, v.v.i., Průmyslová 595, Vestec, Prague 252 50, Czech Republic
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149
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Rauschert I, Aldunate F, Preussner J, Arocena-Sutz M, Peraza V, Looso M, Benech JC, Agrelo R. Promoter hypermethylation as a mechanism for Lamin A/C silencing in a subset of neuroblastoma cells. PLoS One 2017; 12:e0175953. [PMID: 28422997 PMCID: PMC5397038 DOI: 10.1371/journal.pone.0175953] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Accepted: 04/03/2017] [Indexed: 02/07/2023] Open
Abstract
Nuclear lamins support the nuclear envelope and provide anchorage sites for chromatin. They are involved in DNA synthesis, transcription, and replication. It has previously been reported that the lack of Lamin A/C expression in lymphoma and leukaemia is due to CpG island promoter hypermethylation. Here, we provide evidence that Lamin A/C is silenced via this mechanism in a subset of neuroblastoma cells. Moreover, Lamin A/C expression can be restored with a demethylating agent. Importantly, Lamin A/C reintroduction reduced cell growth kinetics and impaired migration, invasion, and anchorage-independent cell growth. Cytoskeletal restructuring was also induced. In addition, the introduction of lamin Δ50, known as Progerin, caused senescence in these neuroblastoma cells. These cells were stiffer and developed a cytoskeletal structure that differed from that observed upon Lamin A/C introduction. Of relevance, short hairpin RNA Lamin A/C depletion in unmethylated neuroblastoma cells enhanced the aforementioned tumour properties. A cytoskeletal structure similar to that observed in methylated cells was induced. Furthermore, atomic force microscopy revealed that Lamin A/C knockdown decreased cellular stiffness in the lamellar region. Finally, the bioinformatic analysis of a set of methylation arrays of neuroblastoma primary tumours showed that a group of patients (around 3%) gives a methylation signal in some of the CpG sites located within the Lamin A/C promoter region analysed by bisulphite sequencing PCR. These findings highlight the importance of Lamin A/C epigenetic inactivation for a subset of neuroblastomas, leading to enhanced tumour properties and cytoskeletal changes. Additionally, these findings may have treatment implications because tumour cells lacking Lamin A/C exhibit more aggressive behaviour.
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Affiliation(s)
- Ines Rauschert
- Laboratory of Cellular Signaling and Nanobiology, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - Fabian Aldunate
- Epigenetics of Cancer and Aging Laboratory, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Jens Preussner
- Bioinformatics Core Unit (BCU), Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Miguel Arocena-Sutz
- Epigenetics of Cancer and Aging Laboratory, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Vanina Peraza
- Epigenetics of Cancer and Aging Laboratory, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Mario Looso
- Bioinformatics Core Unit (BCU), Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Juan C. Benech
- Laboratory of Cellular Signaling and Nanobiology, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - Ruben Agrelo
- Epigenetics of Cancer and Aging Laboratory, Institut Pasteur de Montevideo, Montevideo, Uruguay
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150
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Ranade D, Koul S, Thompson J, Prasad KB, Sengupta K. Chromosomal aneuploidies induced upon Lamin B2 depletion are mislocalized in the interphase nucleus. Chromosoma 2017; 126:223-244. [PMID: 26921073 PMCID: PMC5371638 DOI: 10.1007/s00412-016-0580-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Revised: 01/28/2016] [Accepted: 02/09/2016] [Indexed: 12/31/2022]
Abstract
Chromosome territories assume non-random positions in the interphase nucleus with gene-rich chromosomes localized toward the nuclear interior and gene-poor chromosome territories toward the nuclear periphery. Lamins are intermediate filament proteins of the inner nuclear membrane required for the maintenance of nuclear structure and function. Here, we show using whole-genome expression profiling that Lamin A/C or Lamin B2 depletion in an otherwise diploid colorectal cancer cell line (DLD1) deregulates transcript levels from specific chromosomes. Further, three-dimensional fluorescence in situ hybridization (3D-FISH) analyses of a subset of these transcriptionally deregulated chromosome territories revealed that the diploid chromosome territories in Lamin-depleted cells largely maintain conserved positions in the interphase nucleus in a gene-density-dependent manner. In addition, chromosomal aneuploidies were induced in ~25 % of Lamin A/C or Lamin B2-depleted cells. Sub-populations of these aneuploid cells consistently showed a mislocalization of the gene-rich aneuploid chromosome 19 territory toward the nuclear periphery, while gene-poor aneuploid chromosome 18 territory was mislocalized toward the nuclear interior predominantly upon Lamin B2 than Lamin A/C depletion. In addition, a candidate gene locus ZNF570 (Chr.19q13.12) significantly overexpressed upon Lamin B2 depletion was remarkably repositioned away from the nuclear lamina. Taken together, our studies strongly implicate an overarching role for Lamin B2 in the maintenance of nuclear architecture since loss of Lamin B2 relieves the spatial positional constraints required for maintaining conserved localization of aneuploid chromosome territories in the interphase nucleus.
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Affiliation(s)
- Devika Ranade
- Biology, Indian Institute of Science Education and Research, Pune, Main Building, Homi Bhabha Road, Pashan, Pune, Maharashtra, 411008, India
| | - Shivsmriti Koul
- Biology, Indian Institute of Science Education and Research, Pune, Main Building, Homi Bhabha Road, Pashan, Pune, Maharashtra, 411008, India
| | - Joyce Thompson
- Biology, Indian Institute of Science Education and Research, Pune, Main Building, Homi Bhabha Road, Pashan, Pune, Maharashtra, 411008, India
| | - Kumar Brajesh Prasad
- Biology, Indian Institute of Science Education and Research, Pune, Main Building, Homi Bhabha Road, Pashan, Pune, Maharashtra, 411008, India
| | - Kundan Sengupta
- Biology, Indian Institute of Science Education and Research, Pune, Main Building, Homi Bhabha Road, Pashan, Pune, Maharashtra, 411008, India.
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