301
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Petrie RJ, Yamada KM. Fibroblasts Lead the Way: A Unified View of 3D Cell Motility. Trends Cell Biol 2015; 25:666-674. [PMID: 26437597 DOI: 10.1016/j.tcb.2015.07.013] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 07/09/2015] [Accepted: 07/29/2015] [Indexed: 12/31/2022]
Abstract
Primary human fibroblasts are remarkably adaptable, able to migrate in differing types of physiological 3D tissue and on rigid 2D tissue culture surfaces. The crawling behavior of these and other vertebrate cells has been studied intensively, which has helped generate the concept of the cell motility cycle as a comprehensive model of 2D cell migration. However, this model fails to explain how cells force their large nuclei through the confines of a 3D matrix environment and why primary fibroblasts can use more than one mechanism to move in 3D. Recent work shows that the intracellular localization of myosin II activity is governed by cell-matrix interactions to both force the nucleus through the extracellular matrix (ECM) and dictate the type of protrusions used to migrate in 3D.
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Affiliation(s)
- Ryan J Petrie
- Laboratory of Cell and Developmental Biology, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Kenneth M Yamada
- Laboratory of Cell and Developmental Biology, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA.
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302
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Makarov AA, Rizzotto A, Meinke P, Schirmer EC. Purification of Lamins and Soluble Fragments of NETs. Methods Enzymol 2015; 569:79-100. [PMID: 26778554 DOI: 10.1016/bs.mie.2015.09.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Lamins and associated nuclear envelope transmembrane proteins (NETs) present unique problems for biochemical studies. Lamins form insoluble intermediate filament networks, associate with chromatin, and are also connected via specific NETs to the cytoskeleton, thus further complicating their isolation and purification from mammalian cells. Adding to this complexity, NETs at the inner nuclear membrane function in three distinct environments: (a) their nucleoplasmic domain(s) can bind lamins, chromatin, and transcriptional regulators; (b) they possess one or more integral transmembrane domains; and (c) their lumenal domain(s) function in the unique reducing environment of the nuclear envelope/ER lumen. This chapter describes strategic considerations and protocols to facilitate biochemical studies of lamins and NET proteins in vitro. Studying these proteins in vitro typically involves first expressing specific polypeptide fragments in bacteria and optimizing conditions to purify each fragment. We describe parameters for choosing specific fragments and designing purification strategies and provide detailed purification protocols. Biochemical studies can provide fundamental knowledge including binding strengths and the molecular consequences of disease-causing mutations that will be essential to understand nuclear envelope-genome interactions and nuclear envelope linked disease mechanisms.
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Affiliation(s)
- Alexandr A Makarov
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Andrea Rizzotto
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Peter Meinke
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Eric C Schirmer
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, United Kingdom.
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303
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Ivanovska IL, Shin JW, Swift J, Discher DE. Stem cell mechanobiology: diverse lessons from bone marrow. Trends Cell Biol 2015; 25:523-32. [PMID: 26045259 PMCID: PMC4555184 DOI: 10.1016/j.tcb.2015.04.003] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2014] [Revised: 04/24/2015] [Accepted: 04/27/2015] [Indexed: 12/19/2022]
Abstract
A stem cell niche is defined by various chemical and physical features that influence whether a stem cell remains quiescent, divides, or differentiates. We review mechanical determinants that affect cell fate through actomyosin forces, nucleoskeleton remodeling, and mechanosensitive translocation of transcription factors. Current methods for physical characterization of tissue microenvironments are summarized together with efforts to recapitulate niche mechanics in culture. We focus on mesenchymal stem cells, particularly in osteogenesis and adipogenesis, and on blood stem cells - both of which reside in mechanically diverse marrow microenvironments. Given the explosion of efforts with pluripotent stem cells, the evident mechanosensitivity of clinically relevant, multipotent marrow cells underscores an increasing need to examine and understand in vivo and in vitro physical properties on length scales that cells sense.
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Affiliation(s)
- Irena L Ivanovska
- Molecular and Cell Biophysics Laboratory, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jae-Won Shin
- Molecular and Cell Biophysics Laboratory, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Joe Swift
- Molecular and Cell Biophysics Laboratory, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Dennis E Discher
- Molecular and Cell Biophysics Laboratory, University of Pennsylvania, Philadelphia, PA 19104, USA.
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304
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Thomas DG, Yenepalli A, Denais CM, Rape A, Beach JR, Wang YL, Schiemann WP, Baskaran H, Lammerding J, Egelhoff TT. Non-muscle myosin IIB is critical for nuclear translocation during 3D invasion. J Cell Biol 2015; 210:583-94. [PMID: 26261182 PMCID: PMC4539979 DOI: 10.1083/jcb.201502039] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 07/01/2015] [Indexed: 01/22/2023] Open
Abstract
Non-muscle myosin II (NMII) is reported to play multiple roles during cell migration and invasion. However, the exact biophysical roles of different NMII isoforms during these processes remain poorly understood. We analyzed the contributions of NMIIA and NMIIB in three-dimensional (3D) migration and in generating the forces required for efficient invasion by mammary gland carcinoma cells. Using traction force microscopy and microfluidic invasion devices, we demonstrated that NMIIA is critical for generating force during active protrusion, and NMIIB plays a major role in applying force on the nucleus to facilitate nuclear translocation through tight spaces. We further demonstrate that the nuclear membrane protein nesprin-2 is a possible linker coupling NMIIB-based force generation to nuclear translocation. Together, these data reveal a central biophysical role for NMIIB in nuclear translocation during 3D invasive migration, a result with relevance not only to cancer metastasis but for 3D migration in other settings such as embryonic cell migration and wound healing.
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Affiliation(s)
- Dustin G Thomas
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 441195 Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH 44195
| | - Aishwarya Yenepalli
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 441195
| | - Celine Marie Denais
- Department of Biomedical Engineering, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
| | - Andrew Rape
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA 94720
| | - Jordan R Beach
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Yu-Li Wang
- Department of Biomedical Engineering, Carnegie Melon University, Pittsburgh, PA 15219
| | - William P Schiemann
- General Medical Sciences-Oncology, Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH 44106
| | - Harihara Baskaran
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106
| | - Jan Lammerding
- Department of Biomedical Engineering, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
| | - Thomas T Egelhoff
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 441195 Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH 44195
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305
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Rocha-Perugini V, González-Granado JM. Nuclear envelope lamin-A as a coordinator of T cell activation. Nucleus 2015; 5:396-401. [PMID: 25482193 PMCID: PMC4164483 DOI: 10.4161/nucl.36361] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Nuclear lamins A/C control several critical cellular functions, e.g., chromatin organization, gene transcription, DNA replication, DNA damage responses, cell cycle progression, cell differentiation, and cell polarization during migration. However, few studies have addressed the role of lamins A/C in the control of the functions of immune cells. Recently, we have demonstrated that lamins A/C are induced in T cells upon antigen recognition. Lamins A/C enhance T cell responses by coupling the plasma membrane to the nucleus via the linker of nucleoskeleton and cytoskeleton (LINC) complex and the actin cytoskeleton. Here, we discuss the possible physiological relevance and functional context of lamin A/C in T cell activation and propose a model in which lamins A/C are key modulators of immune cell functions.
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Affiliation(s)
- Vera Rocha-Perugini
- a Servicio de Inmunología; Hospital Universitario de la Princesa; Instituto de Investigación Sanitaria de la Princesa; Madrid, Spain
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306
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Stewart RM, Zubek AE, Rosowski KA, Schreiner SM, Horsley V, King MC. Nuclear-cytoskeletal linkages facilitate cross talk between the nucleus and intercellular adhesions. ACTA ACUST UNITED AC 2015; 209:403-18. [PMID: 25963820 PMCID: PMC4427780 DOI: 10.1083/jcb.201502024] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The linker of nucleoskeleton and cytoskeleton (LINC) complex allows cells to actively control nuclear position by coupling the nucleus to the cytoplasmic cytoskeleton. Nuclear position responds to the formation of intercellular adhesions through coordination with the cytoskeleton, but it is not known whether this response impacts adhesion function. In this paper, we demonstrate that the LINC complex component SUN2 contributes to the mechanical integrity of intercellular adhesions between mammalian epidermal keratinocytes. Mice deficient for Sun2 exhibited irregular hair follicle intercellular adhesions, defective follicle structure, and alopecia. Primary mouse keratinocytes lacking Sun2 displayed aberrant nuclear position in response to adhesion formation, altered desmosome distribution, and mechanically defective adhesions. This dysfunction appeared rooted in a failure of Sun2-null cells to reorganize their microtubule network to support coordinated intercellular adhesion. Together, these results suggest that cross talk between the nucleus, cytoskeleton, and intercellular adhesions is important for epidermal tissue integrity.
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Affiliation(s)
- Rachel M Stewart
- Department of Cell Biology and Department of Dermatology, Yale School of Medicine; and Department of Molecular, Cell and Developmental Biology; Yale University, New Haven, CT, 06520
| | - Amanda E Zubek
- Department of Cell Biology and Department of Dermatology, Yale School of Medicine; and Department of Molecular, Cell and Developmental Biology; Yale University, New Haven, CT, 06520 Department of Cell Biology and Department of Dermatology, Yale School of Medicine; and Department of Molecular, Cell and Developmental Biology; Yale University, New Haven, CT, 06520
| | - Kathryn A Rosowski
- Department of Cell Biology and Department of Dermatology, Yale School of Medicine; and Department of Molecular, Cell and Developmental Biology; Yale University, New Haven, CT, 06520
| | - Sarah M Schreiner
- Department of Cell Biology and Department of Dermatology, Yale School of Medicine; and Department of Molecular, Cell and Developmental Biology; Yale University, New Haven, CT, 06520
| | - Valerie Horsley
- Department of Cell Biology and Department of Dermatology, Yale School of Medicine; and Department of Molecular, Cell and Developmental Biology; Yale University, New Haven, CT, 06520 Department of Cell Biology and Department of Dermatology, Yale School of Medicine; and Department of Molecular, Cell and Developmental Biology; Yale University, New Haven, CT, 06520
| | - Megan C King
- Department of Cell Biology and Department of Dermatology, Yale School of Medicine; and Department of Molecular, Cell and Developmental Biology; Yale University, New Haven, CT, 06520
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307
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Razafsky D, Hodzic D. Nuclear envelope: positioning nuclei and organizing synapses. Curr Opin Cell Biol 2015; 34:84-93. [PMID: 26079712 DOI: 10.1016/j.ceb.2015.06.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 05/28/2015] [Accepted: 06/01/2015] [Indexed: 10/23/2022]
Abstract
The nuclear envelope plays an essential role in nuclear positioning within cells and tissues. This review highlights advances in understanding the mechanisms of nuclear positioning during skeletal muscle and central nervous system development. New findings, particularly about A-type lamins and Nesprin1, may link nuclear envelope integrity to synaptic integrity. Thus synaptic defects, rather than nuclear mispositioning, may underlie human pathologies associated with mutations of nuclear envelope proteins.
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Affiliation(s)
- David Razafsky
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, 660 S. Euclid Avenue, St Louis, MO 63110, USA
| | - Didier Hodzic
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, 660 S. Euclid Avenue, St Louis, MO 63110, USA.
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308
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Nagayama K, Hamaji Y, Sato Y, Matsumoto T. Mechanical trapping of the nucleus on micropillared surfaces inhibits the proliferation of vascular smooth muscle cells but not cervical cancer HeLa cells. J Biomech 2015; 48:1796-803. [PMID: 26054426 DOI: 10.1016/j.jbiomech.2015.05.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 03/14/2015] [Accepted: 05/05/2015] [Indexed: 12/31/2022]
Abstract
The interaction between cells and the extracellular matrix on a topographically patterned surface can result in changes in cell shape and many cellular functions. In the present study, we demonstrated the mechanical deformation and trapping of the intracellular nucleus using polydimethylsiloxane (PDMS)-based microfabricated substrates with an array of micropillars. We investigated the differential effects of nuclear deformation on the proliferation of healthy vascular smooth muscle cells (SMCs) and cervical cancer HeLa cells. Both types of cell spread normally in the space between micropillars and completely invaded the extracellular microstructures, including parts of their cytoplasm and their nuclei. We found that the proliferation of SMCs but not HeLa cells was dramatically inhibited by cultivation on the micropillar substrates, even though remarkable deformation of nuclei was observed in both types of cells. Mechanical testing with an atomic force microscope and a detailed image analysis with confocal microscopy revealed that SMC nuclei had a thicker nuclear lamina and greater expression of lamin A/C than those of HeLa cells, which consequently increased the elastic modulus of the SMC nuclei and their nuclear mechanical resistance against extracellular microstructures. These results indicate that the inhibition of cell proliferation resulted from deformation of the mature lamin structures, which might be exposed to higher internal stress during nuclear deformation. This nuclear stress-induced inhibition of cell proliferation occurred rarely in cancer cells with deformable nuclei.
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Affiliation(s)
- Kazuaki Nagayama
- Micro-Nano Biomechanics Laboratory, Department of Intelligent Systems Engineering, Ibaraki University, Nakanarusawa-cho, Hitachi 316-8511, Japan.
| | - Yumi Hamaji
- Biomechanics Laboratory, Department of Mechanical Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
| | - Yuji Sato
- Biomechanics Laboratory, Department of Mechanical Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
| | - Takeo Matsumoto
- Biomechanics Laboratory, Department of Mechanical Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan.
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309
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Mechanical stimulation induces formin-dependent assembly of a perinuclear actin rim. Proc Natl Acad Sci U S A 2015; 112:E2595-601. [PMID: 25941386 DOI: 10.1073/pnas.1504837112] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Cells constantly sense and respond to mechanical signals by reorganizing their actin cytoskeleton. Although a number of studies have explored the effects of mechanical stimuli on actin dynamics, the immediate response of actin after force application has not been studied. We designed a method to monitor the spatiotemporal reorganization of actin after cell stimulation by local force application. We found that force could induce transient actin accumulation in the perinuclear region within ∼ 2 min. This actin reorganization was triggered by an intracellular Ca(2+) burst induced by force application. Treatment with the calcium ionophore A23187 recapitulated the force-induced perinuclear actin remodeling. Blocking of actin polymerization abolished this process. Overexpression of Klarsicht, ANC-1, Syne Homology (KASH) domain to displace nesprins from the nuclear envelope did not abolish Ca(2+)-dependent perinuclear actin assembly. However, the endoplasmic reticulum- and nuclear membrane-associated inverted formin-2 (INF2), a potent actin polymerization activator (mutations of which are associated with several genetic diseases), was found to be important for perinuclear actin assembly. The perinuclear actin rim structure colocalized with INF2 on stimulation, and INF2 depletion resulted in attenuation of the rim formation. Our study suggests that cells can respond rapidly to external force by remodeling perinuclear actin in a unique Ca(2+)- and INF2-dependent manner.
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310
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Li Q, Makhija E, Hameed F, Shivashankar G. Micropillar displacements by cell traction forces are mechanically correlated with nuclear dynamics. Biochem Biophys Res Commun 2015; 461:372-7. [DOI: 10.1016/j.bbrc.2015.04.041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 04/07/2015] [Indexed: 12/31/2022]
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311
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Direct force probe reveals the mechanics of nuclear homeostasis in the mammalian cell. Proc Natl Acad Sci U S A 2015; 112:5720-5. [PMID: 25901323 DOI: 10.1073/pnas.1502111112] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
How cells maintain nuclear shape and position against various intracellular and extracellular forces is not well understood, although defects in nuclear mechanical homeostasis are associated with a variety of human diseases. We estimated the force required to displace and deform the nucleus in adherent living cells with a technique to locally pull the nuclear surface. A minimum pulling force of a few nanonewtons--far greater than typical intracellular motor forces--was required to significantly displace and deform the nucleus. Upon force removal, the original shape and position were restored quickly within a few seconds. This stiff, elastic response required the presence of vimentin, lamin A/C, and SUN (Sad1p, UNC-84)-domain protein linkages, but not F-actin or microtubules. Although F-actin and microtubules are known to exert mechanical forces on the nuclear surface through molecular motor activity, we conclude that the intermediate filament networks maintain nuclear mechanical homeostasis against localized forces.
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312
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Razafsky D, Hodzic D. A variant of Nesprin1 giant devoid of KASH domain underlies the molecular etiology of autosomal recessive cerebellar ataxia type I. Neurobiol Dis 2015; 78:57-67. [PMID: 25843669 DOI: 10.1016/j.nbd.2015.03.027] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 03/24/2015] [Accepted: 03/26/2015] [Indexed: 12/21/2022] Open
Abstract
Nonsense mutations across the whole coding sequence of Syne1/Nesprin1 have been linked to autosomal recessive cerebellar ataxia Type I (ARCA1). However, nothing is known about the molecular etiology of this late-onset debilitating pathology. In this work, we report that Nesprin1 giant is specifically expressed in CNS tissues. We also identified a CNS-specific splicing event that leads to the abundant expression of a KASH-LESS variant of Nesprin1 giant (KLNes1g) in the cerebellum. KLNes1g displayed a noncanonical localization at glomeruli of cerebellar mossy fibers whereas Nesprin2 exclusively decorated the nuclear envelope of all cerebellar neurons. In immunogold electron microscopy, KLNes1g colocalized both with synaptic vesicles within mossy fibers and with dendritic membranes of cerebellar granule neurons. We further identified vesicle- and membrane-associated proteins in KLNes1g immunoprecipitates. Together, our results suggest that the loss of function of KLNes1g resulting from Nesprin1 nonsense mutations underlies the molecular etiology of ARCA1.
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Affiliation(s)
- David Razafsky
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, 660 S. Euclid, St Louis, MO 63110, USA
| | - Didier Hodzic
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, 660 S. Euclid, St Louis, MO 63110, USA.
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313
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Gay S, Foiani M. Nuclear envelope and chromatin, lock and key of genome integrity. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 317:267-330. [PMID: 26008788 DOI: 10.1016/bs.ircmb.2015.03.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
More than as an inert separation between the inside and outside of the nucleus, the nuclear envelope (NE) constitutes an active toll, which controls the import and export of molecules, and also a hub for a diversity of genomic processes, such as transcription, DNA repair, and chromatin dynamics. Proteins localized at the inner surface of the NE (such as lamins, nuclear pore proteins, lamin-associated proteins) interact with chromatin in a dynamic manner, contributing to the establishment of topological domains. In this review, we address the complex interplay between chromatin and NE. We discuss the divergence of this cross talk during evolution and comment both on the current established models and the most recent findings. In particular, we focus our attention on how the NE cooperates with chromatin in protecting the genome integrity.
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Affiliation(s)
- Sophie Gay
- IFOM, the FIRC Institute of Molecular Oncology, Milan, Italy
| | - Marco Foiani
- IFOM, the FIRC Institute of Molecular Oncology, Milan, Italy; Dipartimento di Scienze Biomolecolari e Biotecnologie, Università degli Studi di Milano, Milan, Italy
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314
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Abstract
The intermediate filament proteins, A- and B-type lamins, form the nuclear lamina scaffold adjacent to the inner nuclear membrane. Lamins also contribute to chromatin regulation and various signaling pathways affecting gene expression. In this review, Osmanagic-Myers et al. focus on the role of nuclear lamins in mechanosensing and also discuss how disease-linked lamin mutants may impair the response of cells to mechanical stimuli and influence the properties of the extracellular matrix. The intermediate filament proteins, A- and B-type lamins, form the nuclear lamina scaffold adjacent to the inner nuclear membrane. B-type lamins confer elasticity, while A-type lamins lend viscosity and stiffness to nuclei. Lamins also contribute to chromatin regulation and various signaling pathways affecting gene expression. The mechanical roles of lamins and their functions in gene regulation are often viewed as independent activities, but recent findings suggest a highly cross-linked and interdependent regulation of these different functions, particularly in mechanosignaling. In this newly emerging concept, lamins act as a “mechanostat” that senses forces from outside and responds to tension by reinforcing the cytoskeleton and the extracellular matrix. A-type lamins, emerin, and the linker of the nucleoskeleton and cytoskeleton (LINC) complex directly transmit forces from the extracellular matrix into the nucleus. These mechanical forces lead to changes in the molecular structure, modification, and assembly state of A-type lamins. This in turn activates a tension-induced “inside-out signaling” through which the nucleus feeds back to the cytoskeleton and the extracellular matrix to balance outside and inside forces. These functions regulate differentiation and may be impaired in lamin-linked diseases, leading to cellular phenotypes, particularly in mechanical load-bearing tissues.
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315
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Continual cell deformation induced via attachment to oriented fibers enhances fibroblast cell migration. PLoS One 2015; 10:e0119094. [PMID: 25774792 PMCID: PMC4361054 DOI: 10.1371/journal.pone.0119094] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Accepted: 01/09/2015] [Indexed: 12/15/2022] Open
Abstract
Fibroblast migration is critical to the wound healing process. In vivo, migration occurs on fibrillar substrates, and previous observations have shown that a significant time lag exists before the onset of granulation tissue. We therefore conducted a series of experiments to understand the impact of both fibrillar morphology and migration time. Substrate topography was first shown to have a profound influence. Fibroblasts preferentially attach to fibrillar surfaces, and orient their cytoplasm for maximal contact with the fiber edge. In the case of en-mass cell migration out of an agarose droplet, fibroblasts on flat surfaces emerged with an enhanced velocity, v = 52μm/h, that decreases to the single cell value, v = 28μm/h within 24 hours and remained constant for at least four days. Fibroblasts emerging on fibrillar surfaces emerged with the single cell velocity, which remained constant for the first 24 hours and then increased reaching a plateau with more than twice the initial velocity within the next three days. The focal adhesions were distributed uniformly in cells on flat surfaces, while on the fibrillar surface they were clustered along the cell periphery. Furthermore, the number of focal adhesions for the cells on the flat surfaces remained constant, while it decreased on the fibrillar surface during the next three days. The deformation of the cell nuclei was found to be 50% larger on the fiber surfaces for the first 24 hours. While the mean deformation remained constant on the flat surface, it increased for the next three days by 24% in cells on fibers. On the fourth day, large actin/myosin fibers formed in cells on fibrillar surfaces only and coincided with a change from the standard migration mechanism involving extension of lamellipodia, and retraction of the rear, to one involving strong contractions oriented along the fibers and centered about the nucleus.
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316
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Plessner M, Melak M, Chinchilla P, Baarlink C, Grosse R. Nuclear F-actin formation and reorganization upon cell spreading. J Biol Chem 2015; 290:11209-16. [PMID: 25759381 DOI: 10.1074/jbc.m114.627166] [Citation(s) in RCA: 180] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Indexed: 12/30/2022] Open
Abstract
We recently discovered signal-regulated nuclear actin network assembly. However, in contrast to cytoplasmic actin regulation, polymeric nuclear actin structures and functions remain only poorly understood. Here we describe a novel molecular tool to visualize real-time nuclear actin dynamics by targeting the Actin-Chromobody-TagGFP to the nucleus, thus establishing a nuclear Actin-Chromobody. Interestingly, we observe nuclear actin polymerization into dynamic filaments upon cell spreading and fibronectin stimulation, both of which appear to be triggered by integrin signaling. Furthermore, we show that nucleoskeletal proteins such as the LINC (linker of nucleoskeleton and cytoskeleton) complex and components of the nuclear lamina couple cell spreading or integrin activation by fibronectin to nuclear actin polymerization. Spreading-induced nuclear actin polymerization results in serum response factor (SRF)-mediated transcription through nuclear retention of myocardin-related transcription factor A (MRTF-A). Our results reveal a signaling pathway, which links integrin activation by extracellular matrix interaction to nuclear actin polymerization through the LINC complex, and therefore suggest a role for nuclear actin polymerization in the context of cellular adhesion and mechanosensing.
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Affiliation(s)
- Matthias Plessner
- From the Institute of Pharmacology, Biochemical-Pharmacological Center (BPC), University of Marburg, Karl-von-Frisch-Strasse 1, 35043 Marburg, Germany
| | - Michael Melak
- From the Institute of Pharmacology, Biochemical-Pharmacological Center (BPC), University of Marburg, Karl-von-Frisch-Strasse 1, 35043 Marburg, Germany
| | - Pilar Chinchilla
- From the Institute of Pharmacology, Biochemical-Pharmacological Center (BPC), University of Marburg, Karl-von-Frisch-Strasse 1, 35043 Marburg, Germany
| | - Christian Baarlink
- From the Institute of Pharmacology, Biochemical-Pharmacological Center (BPC), University of Marburg, Karl-von-Frisch-Strasse 1, 35043 Marburg, Germany
| | - Robert Grosse
- From the Institute of Pharmacology, Biochemical-Pharmacological Center (BPC), University of Marburg, Karl-von-Frisch-Strasse 1, 35043 Marburg, Germany
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317
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Chang W, Worman HJ, Gundersen GG. Accessorizing and anchoring the LINC complex for multifunctionality. ACTA ACUST UNITED AC 2015; 208:11-22. [PMID: 25559183 PMCID: PMC4284225 DOI: 10.1083/jcb.201409047] [Citation(s) in RCA: 210] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The linker of nucleoskeleton and cytoskeleton (LINC) complex, composed of outer and inner nuclear membrane Klarsicht, ANC-1, and Syne homology (KASH) and Sad1 and UNC-84 (SUN) proteins, respectively, connects the nucleus to cytoskeletal filaments and performs diverse functions including nuclear positioning, mechanotransduction, and meiotic chromosome movements. Recent studies have shed light on the source of this diversity by identifying factors associated with the complex that endow specific functions as well as those that differentially anchor the complex within the nucleus. Additional diversity may be provided by accessory factors that reorganize the complex into higher-ordered arrays. As core components of the LINC complex are associated with several diseases, understanding the role of accessory and anchoring proteins could provide insights into pathogenic mechanisms.
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Affiliation(s)
- Wakam Chang
- Department of Pathology and Cell Biology and Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY 10032
| | - Howard J Worman
- Department of Pathology and Cell Biology and Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY 10032 Department of Pathology and Cell Biology and Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY 10032
| | - Gregg G Gundersen
- Department of Pathology and Cell Biology and Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY 10032
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318
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Dupin I, Elric J, Etienne-Manneville S. Adhesive micropatterns to study intermediate filament function in nuclear positioning. ACTA ACUST UNITED AC 2015; 66:13.7.1-13.7.19. [PMID: 25727329 DOI: 10.1002/0471143030.cb1307s66] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The nucleus is generally found near the cell center; however its position can vary in response to extracellular or intracellular signals, leading to a polarized intracellular organization. Nuclear movement is mediated by the cytoskeleton and its associated motors. While the role of actin and microtubule cytoskeletons in nuclear positioning has been assessed in various systems, the contribution of intermediate filaments is less established due in part to the lack of tools to study intermediate filament functions. The methods described here use micropatterned substrates to impose reproducible cell shape and nucleus position. Intermediate filament organization can be perturbed using gene downregulation or upregulation; intermediate filaments can also be visualized using fluorescent intermediate filament proteins. This protocol is valuable for characterizing the role of intermediate filaments in a variety of live or fixed adherent cells.
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Affiliation(s)
- Isabelle Dupin
- Universite Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux, France.,INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
| | - Julien Elric
- Institut Pasteur, Cell polarity and migration group and CNRS URA 2582, Paris, France
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319
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Gruenbaum Y, Foisner R. Lamins: nuclear intermediate filament proteins with fundamental functions in nuclear mechanics and genome regulation. Annu Rev Biochem 2015; 84:131-64. [PMID: 25747401 DOI: 10.1146/annurev-biochem-060614-034115] [Citation(s) in RCA: 368] [Impact Index Per Article: 40.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Lamins are intermediate filament proteins that form a scaffold, termed nuclear lamina, at the nuclear periphery. A small fraction of lamins also localize throughout the nucleoplasm. Lamins bind to a growing number of nuclear protein complexes and are implicated in both nuclear and cytoskeletal organization, mechanical stability, chromatin organization, gene regulation, genome stability, differentiation, and tissue-specific functions. The lamin-based complexes and their specific functions also provide insights into possible disease mechanisms for human laminopathies, ranging from muscular dystrophy to accelerated aging, as observed in Hutchinson-Gilford progeria and atypical Werner syndromes.
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Affiliation(s)
- Yosef Gruenbaum
- Department of Genetics, Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem 91904, Israel;
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320
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Huber F, Boire A, López MP, Koenderink GH. Cytoskeletal crosstalk: when three different personalities team up. Curr Opin Cell Biol 2015; 32:39-47. [DOI: 10.1016/j.ceb.2014.10.005] [Citation(s) in RCA: 187] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 10/20/2014] [Accepted: 10/22/2014] [Indexed: 12/29/2022]
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321
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Cell guidance into quiescent state through chromatin remodeling induced by elastic modulus of substrate. Biomaterials 2015; 37:144-55. [DOI: 10.1016/j.biomaterials.2014.10.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 10/02/2014] [Indexed: 12/11/2022]
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322
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Abstract
Aging is a complex, multifaceted process that induces a myriad of physiological changes over an extended period of time. Aging is accompanied by major biochemical and biomechanical changes at macroscopic and microscopic length scales that affect not only tissues and organs but also cells and subcellular organelles. These changes include transcriptional and epigenetic modifications; changes in energy production within mitochondria; and alterations in the overall mechanics of cells, their nuclei, and their surrounding extracellular matrix. In addition, aging influences the ability of cells to sense changes in extracellular-matrix compliance (mechanosensation) and to transduce these changes into biochemical signals (mechanotransduction). Moreover, following a complex positive-feedback loop, aging is accompanied by changes in the composition and structure of the extracellular matrix, resulting in changes in the mechanics of connective tissues in older individuals. Consequently, these progressive dysfunctions facilitate many human pathologies and deficits that are associated with aging, including cardiovascular, musculoskeletal, and neurodegenerative disorders and diseases. Here, we critically review recent work highlighting some of the primary biophysical changes occurring in cells and tissues that accompany the aging process.
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Affiliation(s)
- Jude M Phillip
- Department of Chemical and Biomolecular Engineering, Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, Maryland, 21218
- Johns Hopkins Physical Sciences-Oncology Center, Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, Maryland, 21218
| | - Ivie Aifuwa
- Department of Chemical and Biomolecular Engineering, Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, Maryland, 21218
- Johns Hopkins Physical Sciences-Oncology Center, Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, Maryland, 21218
| | - Jeremy Walston
- Department of Medicine, Division of Geriatric Medicine and Gerontology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21224
| | - Denis Wirtz
- Department of Chemical and Biomolecular Engineering, Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, Maryland, 21218
- Johns Hopkins Physical Sciences-Oncology Center, Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, Maryland, 21218
- Departments of Oncology and Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21231
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323
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Affiliation(s)
- Alexandre J Kabla
- Engineering Department - Cambridge University, Baker building, Trumpington Street, Cambridge, CB2 1PZ, Royaume-Uni
| | - Kevin Chalut
- Wellcome Trust Centre for Stem Cell Research, Cambridge CB2 1PZ, Royaume-Uni
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324
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Versaevel M, Braquenier JB, Riaz M, Grevesse T, Lantoine J, Gabriele S. Super-resolution microscopy reveals LINC complex recruitment at nuclear indentation sites. Sci Rep 2014; 4:7362. [PMID: 25482017 PMCID: PMC4258653 DOI: 10.1038/srep07362] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 11/19/2014] [Indexed: 01/12/2023] Open
Abstract
Increasing evidences show that the actin cytoskeleton is a key parameter of the nuclear remodeling process in response to the modifications of cellular morphology. However, detailed information on the interaction between the actin cytoskeleton and the nuclear lamina was still lacking. We addressed this question by constraining endothelial cells on rectangular fibronectin-coated micropatterns and then using Structured Illumination Microscopy (SIM) to observe the interactions between actin stress fibers, nuclear lamina and LINC complexes at a super-resolution scale. Our results show that tension in apical actin stress fibers leads to deep nuclear indentations that significantly deform the nuclear lamina. Interestingly, indented nuclear zones are characterized by a local enrichment of LINC complexes, which anchor apical actin fibers to the nuclear lamina. Moreover, our findings indicate that nuclear indentations induce the formation of segregated domains of condensed chromatin. However, nuclear indentations and condensed chromatin domains are not irreversible processes and both can relax in absence of tension in apical actin stress fibers.
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Affiliation(s)
- Marie Versaevel
- Mechanobiology &Soft Matter Group, Interfaces and Complex Fluids Laboratory, Research Institute for Biosciences, CIRMAP, University of Mons, 20 Place du Parc B-7000 Mons, Belgium
| | | | - Maryam Riaz
- Mechanobiology &Soft Matter Group, Interfaces and Complex Fluids Laboratory, Research Institute for Biosciences, CIRMAP, University of Mons, 20 Place du Parc B-7000 Mons, Belgium
| | - Thomas Grevesse
- Mechanobiology &Soft Matter Group, Interfaces and Complex Fluids Laboratory, Research Institute for Biosciences, CIRMAP, University of Mons, 20 Place du Parc B-7000 Mons, Belgium
| | - Joséphine Lantoine
- Mechanobiology &Soft Matter Group, Interfaces and Complex Fluids Laboratory, Research Institute for Biosciences, CIRMAP, University of Mons, 20 Place du Parc B-7000 Mons, Belgium
| | - Sylvain Gabriele
- Mechanobiology &Soft Matter Group, Interfaces and Complex Fluids Laboratory, Research Institute for Biosciences, CIRMAP, University of Mons, 20 Place du Parc B-7000 Mons, Belgium
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325
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Chen W, Shao Y, Li X, Zhao G, Fu J. Nanotopographical Surfaces for Stem Cell Fate Control: Engineering Mechanobiology from the Bottom. NANO TODAY 2014; 9:759-784. [PMID: 25883674 PMCID: PMC4394389 DOI: 10.1016/j.nantod.2014.12.002] [Citation(s) in RCA: 148] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
During embryogenesis and tissue maintenance and repair in an adult organism, a myriad of stem cells are regulated by their surrounding extracellular matrix (ECM) enriched with tissue/organ-specific nanoscale topographical cues to adopt different fates and functions. Attributed to their capability of self-renewal and differentiation into most types of somatic cells, stem cells also hold tremendous promise for regenerative medicine and drug screening. However, a major challenge remains as to achieve fate control of stem cells in vitro with high specificity and yield. Recent exciting advances in nanotechnology and materials science have enabled versatile, robust, and large-scale stem cell engineering in vitro through developments of synthetic nanotopographical surfaces mimicking topological features of stem cell niches. In addition to generating new insights for stem cell biology and embryonic development, this effort opens up unlimited opportunities for innovations in stem cell-based applications. This review is therefore to provide a summary of recent progress along this research direction, with perspectives focusing on emerging methods for generating nanotopographical surfaces and their applications in stem cell research. Furthermore, we provide a review of classical as well as emerging cellular mechano-sensing and -transduction mechanisms underlying stem cell nanotopography sensitivity and also give some hypotheses in regard to how a multitude of signaling events in cellular mechanotransduction may converge and be integrated into core pathways controlling stem cell fate in response to extracellular nanotopography.
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Affiliation(s)
- Weiqiang Chen
- Integrated Biosystems and Biomechanics Laboratory, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yue Shao
- Integrated Biosystems and Biomechanics Laboratory, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Xiang Li
- Integrated Biosystems and Biomechanics Laboratory, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Gang Zhao
- Department of Electronic Science and Technology, University of Science and Technology of China, Hefei 230027, P. R. China
| | - Jianping Fu
- Integrated Biosystems and Biomechanics Laboratory, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
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326
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Ramdas NM, Shivashankar GV. Cytoskeletal control of nuclear morphology and chromatin organization. J Mol Biol 2014; 427:695-706. [PMID: 25281900 DOI: 10.1016/j.jmb.2014.09.008] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 09/03/2014] [Accepted: 09/06/2014] [Indexed: 02/06/2023]
Abstract
The nucleus is sculpted toward various morphologies during cellular differentiation and development. Alterations in nuclear shape often result in changes to chromatin organization and genome function. This is thought to be reflective of its role as a cellular mechanotransducer. Recent evidence has highlighted the importance of cytoskeletal organization in defining how nuclear morphology regulates chromatin dynamics. However, the mechanisms underlying cytoskeletal control of chromatin remodeling are not well understood. We demonstrate here the differential influence of perinuclear actin- and microtubule-driven assemblies on nuclear architecture using pharmacological inhibitors and targeted RNA interference knockdown of cytoskeleton components in Drosophila cells. We find evidence that the loss of perinuclear actin assembly results in basolateral enhancement of microtubule organization and this is reflected functionally by enhanced nuclear dynamics. Cytoskeleton reorganization leads to nuclear lamina deformation that influences heterochromatin localization and core histone protein mobility. We also show that modulations in actin-microtubule assembly result in differential gene expression patterns. Taken together, we suggest that perinuclear actin and basolateral microtubule organization exerts mechanical control on nuclear morphology and chromatin dynamics.
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Affiliation(s)
- Nisha M Ramdas
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore 560 065, India
| | - G V Shivashankar
- Mechanobiology Institute and Department of Biological Sciences, National University of Singapore, 21 Lower Kent Ridge Road 119077, Singapore.
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327
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Petrie RJ, Koo H, Yamada KM. Generation of compartmentalized pressure by a nuclear piston governs cell motility in a 3D matrix. Science 2014; 345:1062-5. [PMID: 25170155 DOI: 10.1126/science.1256965] [Citation(s) in RCA: 242] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Cells use actomyosin contractility to move through three-dimensional (3D) extracellular matrices. Contractility affects the type of protrusions cells use to migrate in 3D, but the mechanisms are unclear. In this work, we found that contractility generated high-pressure lobopodial protrusions in human cells migrating in a 3D matrix. In these cells, the nucleus physically divided the cytoplasm into forward and rear compartments. Actomyosin contractility with the nucleoskeleton-intermediate filament linker protein nesprin-3 pulled the nucleus forward and pressurized the front of the cell. Reducing expression of nesprin-3 decreased and equalized the intracellular pressure. Thus, the nucleus can act as a piston that physically compartmentalizes the cytoplasm and increases the hydrostatic pressure between the nucleus and the leading edge of the cell to drive lamellipodia-independent 3D cell migration.
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Affiliation(s)
- Ryan J Petrie
- Laboratory of Cell and Developmental Biology, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892-4370, USA.
| | - Hyun Koo
- Laboratory of Cell and Developmental Biology, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892-4370, USA. Center for Oral Biology, Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA. Biofilm Research Labs, Levy Center for Oral Health, Department of Orthodontics, University of Pennsylvania School of Dental Medicine, Philadelphia, PA 19104-6030, USA
| | - Kenneth M Yamada
- Laboratory of Cell and Developmental Biology, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892-4370, USA.
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328
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Wu J, Kent IA, Shekhar N, Chancellor TJ, Mendonca A, Dickinson RB, Lele TP. Actomyosin pulls to advance the nucleus in a migrating tissue cell. Biophys J 2014; 106:7-15. [PMID: 24411232 DOI: 10.1016/j.bpj.2013.11.4489] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2013] [Revised: 10/29/2013] [Accepted: 11/19/2013] [Indexed: 01/14/2023] Open
Abstract
The cytoskeletal forces involved in translocating the nucleus in a migrating tissue cell remain unresolved. Previous studies have variously implicated actomyosin-generated pushing or pulling forces on the nucleus, as well as pulling by nucleus-bound microtubule motors. We found that the nucleus in an isolated migrating cell can move forward without any trailing-edge detachment. When a new lamellipodium was triggered with photoactivation of Rac1, the nucleus moved toward the new lamellipodium. This forward motion required both nuclear-cytoskeletal linkages and myosin activity. Apical or basal actomyosin bundles were found not to translate with the nucleus. Although microtubules dampen fluctuations in nuclear position, they are not required for forward translocation of the nucleus during cell migration. Trailing-edge detachment and pulling with a microneedle produced motion and deformation of the nucleus suggestive of a mechanical coupling between the nucleus and the trailing edge. Significantly, decoupling the nucleus from the cytoskeleton with KASH overexpression greatly decreased the frequency of trailing-edge detachment. Collectively, these results explain how the nucleus is moved in a crawling fibroblast and raise the possibility that forces could be transmitted from the front to the back of the cell through the nucleus.
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Affiliation(s)
- Jun Wu
- Department of Chemical Engineering, University of Florida, Gainesville, Florida
| | - Ian A Kent
- Department of Chemical Engineering, University of Florida, Gainesville, Florida
| | - Nandini Shekhar
- Department of Chemical Engineering, University of Florida, Gainesville, Florida
| | - T J Chancellor
- Department of Chemical Engineering, University of Florida, Gainesville, Florida
| | - Agnes Mendonca
- Department of Chemical Engineering, University of Florida, Gainesville, Florida
| | - Richard B Dickinson
- Department of Chemical Engineering, University of Florida, Gainesville, Florida
| | - Tanmay P Lele
- Department of Chemical Engineering, University of Florida, Gainesville, Florida.
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329
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Affiliation(s)
- Douglas W. DeSimone
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA 22903, USA
| | - A. Rick Horwitz
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA 22903, USA
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330
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Abstract
The nucleus is the defining feature of eukaryotic cells and often represents the largest organelle. Over the past decade, it has become apparent that the nucleus is tightly integrated into the structural network of the cell through so-called LINC (linker of the nucleoskeleton and cytoskeleton) complexes, which enable transmission of forces between the nucleus and cytoskeleton. This physical connection between the nucleus and the cytoskeleton is essential for a broad range of cellular functions, including intracellular nuclear movement and positioning, cytoskeletal organization, cell polarization, and cell migration. Recent reports further indicate that forces transmitted from the extracellular matrix to the nucleus via the cytoskeleton may also directly contribute to the cell's ability to probe its mechanical environment by triggering force-induced changes in nuclear structures. In addition, it is now emerging that the physical properties of the nucleus play a crucial role during cell migration in three-dimensional (3D) environments, where cells often have to transit through narrow constrictions that are smaller than the nuclear diameter, e.g., during development, wound healing, or cancer metastasis. In this review, we provide a brief overview of how LINC complex proteins and lamins facilitate nucleo-cytoskeletal coupling, highlight recent findings regarding the role of the nucleus in cellular mechanotransduction and cell motility in 3D environments, and discuss how mutations and/or changes in the expression of these nuclear envelope proteins can result in a broad range of human diseases, including muscular dystrophy, dilated cardiomyopathy, and premature aging.
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331
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Fedorchak GR, Kaminski A, Lammerding J. Cellular mechanosensing: getting to the nucleus of it all. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2014; 115:76-92. [PMID: 25008017 PMCID: PMC4252489 DOI: 10.1016/j.pbiomolbio.2014.06.009] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 06/28/2014] [Indexed: 12/12/2022]
Abstract
Cells respond to mechanical forces by activating specific genes and signaling pathways that allow the cells to adapt to their physical environment. Examples include muscle growth in response to exercise, bone remodeling based on their mechanical load, or endothelial cells aligning under fluid shear stress. While the involved downstream signaling pathways and mechanoresponsive genes are generally well characterized, many of the molecular mechanisms of the initiating 'mechanosensing' remain still elusive. In this review, we discuss recent findings and accumulating evidence suggesting that the cell nucleus plays a crucial role in cellular mechanotransduction, including processing incoming mechanoresponsive signals and even directly responding to mechanical forces. Consequently, mutations in the involved proteins or changes in nuclear envelope composition can directly impact mechanotransduction signaling and contribute to the development and progression of a variety of human diseases, including muscular dystrophy, cancer, and the focus of this review, dilated cardiomyopathy. Improved insights into the molecular mechanisms underlying nuclear mechanotransduction, brought in part by the emergence of new technologies to study intracellular mechanics at high spatial and temporal resolution, will not only result in a better understanding of cellular mechanosensing in normal cells but may also lead to the development of novel therapies in the many diseases linked to defects in nuclear envelope proteins.
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Affiliation(s)
- Gregory R Fedorchak
- Department of Biomedical Engineering, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - Ashley Kaminski
- Department of Biomedical Engineering, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - Jan Lammerding
- Department of Biomedical Engineering, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA.
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332
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King SJ, Nowak K, Suryavanshi N, Holt I, Shanahan CM, Ridley AJ. Nesprin-1 and nesprin-2 regulate endothelial cell shape and migration. Cytoskeleton (Hoboken) 2014; 71:423-34. [PMID: 24931616 DOI: 10.1002/cm.21182] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 06/06/2014] [Accepted: 06/09/2014] [Indexed: 12/26/2022]
Abstract
Nesprins are large multi-domain proteins that link the nuclear envelope to the cytoskeleton and nucleoskeleton. Here we show that nesprin-1 and nesprin-2 play important roles in regulating cell shape and migration in endothelial cells. Nesprin-1 or nesprin-2 depletion by RNAi increased endothelial cell spread area and the length of cellular protrusions, as well as stimulating stress fibre assembly which correlated with an increase in F-actin levels. Nuclear area was also increased by nesprin depletion, and localization of the inner nuclear membrane protein emerin to the nuclear envelope was reduced. Depletion of nesprin-1 or nesprin-2 reduced migration of endothelial cells into a cell-free area, and decreased loop formation in an in vitro angiogenesis assay. Taken together, our results indicate that nesprin-1 and nesprin-2 both regulate nuclear and cytoplasmic architecture, which we propose leads to their effects on endothelial cell migration and angiogenic loop formation.
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Affiliation(s)
- Samantha J King
- Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, Guy's Campus, London, SE1 1UL, United Kingdom; Cardiovascular Division and British Heart Foundation Centre of Research Excellence, King's College London, James Black Centre, Denmark Hill Campus, London, SE5 9NU, United Kingdom
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333
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Nuclear deformability constitutes a rate-limiting step during cell migration in 3-D environments. Cell Mol Bioeng 2014; 7:293-306. [PMID: 25436017 DOI: 10.1007/s12195-014-0342-y] [Citation(s) in RCA: 200] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Cell motility plays a critical role in many physiological and pathological settings, ranging from wound healing to cancer metastasis. While cell migration on 2-dimensional (2-D) substrates has been studied for decades, the physical challenges cells face when moving in 3-D environments are only now emerging. In particular, the cell nucleus, which occupies a large fraction of the cell volume and is normally substantially stiffer than the surrounding cytoplasm, may impose a major obstacle when cells encounter narrow constrictions in the interstitial space, the extracellular matrix, or small capillaries. Using novel microfluidic devices that allow observation of cells moving through precisely defined geometries at high spatial and temporal resolution, we determined nuclear deformability as a critical factor in the cells' ability to pass through constrictions smaller than the size of the nucleus. Furthermore, we found that cells with reduced levels of the nuclear envelope proteins lamins A/C, which are the main determinants of nuclear stiffness, passed significantly faster through narrow constrictions during active migration and passive perfusion. Given recent reports that many human cancers have altered lamin expression, our findings suggest a novel biophysical mechanism by which changes in nuclear structure and composition may promote cancer cell invasion and metastasis.
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334
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Kim D, Kim J, Hyun H, Kim K, Roh S. A nanoscale ridge/groove pattern arrayed surface enhances adipogenic differentiation of human supernumerary tooth-derived dental pulp stem cells in vitro. Arch Oral Biol 2014; 59:765-74. [PMID: 24837475 DOI: 10.1016/j.archoralbio.2014.04.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 04/23/2014] [Indexed: 12/13/2022]
Abstract
OBJECTIVE The aim of this study was to establish human dental pulp stem cells (hDPSCs) from supernumerary teeth and determine the effects of a 350-nm nano-patterned surface on adipogenic and osteogenic differentiation of hDPSCs. DESIGN Several surface markers were analysed by FACS to confirm the isolated cells as hDPSCs. To demonstrate the effects of a nano-patterned surface on the differentiation of hDPSCs, the cells were cultured on a nano-patterned surface with or without adipogenic or osteogenic induction factors. Cells were then stained with Oil red O or Alizarin red, and the lineage specific genes LPL and Runx-2 were analysed by real-time PCR at 3, 6 and 9 days after culture. RESULTS The hDPSCs on a nano-patterned surface showed a linear arrangement compared to irregular cells on a conventional surface. During adipogenic differentiation, more Oil red O stained cells were found in the nano-patterned group than in the conventional group. On the other hand, there was no significant difference in Alizarin red staining between the nano-pattern and conventional surface groups after induction of osteogenic differentiation. Gene expression analyses revealed significantly higher expression of LPL in the nano-patterned group than in the conventional group, whereas Runx-2 expression was higher in the conventional group than in the nano-patterned group. CONCLUSION This study showed that a nano-patterned surface may be able to enhance adipogenic differentiation of hDPSCs by altering their morphology and gene expression patterns, whereas the same surface may inhibit or suppress osteogenic differentiation of the cells.
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Affiliation(s)
- Daehwan Kim
- Cellular Reprogramming & Embryo Biotechnology Laboratory, Seoul National University School of Dentistry, 101 Daehak-ro, Jongno-gu, Seoul 110-749, Republic of Korea.
| | - Jongwook Kim
- Cellular Reprogramming & Embryo Biotechnology Laboratory, Seoul National University School of Dentistry, 101 Daehak-ro, Jongno-gu, Seoul 110-749, Republic of Korea.
| | - Hongkeun Hyun
- Department of Pediatric Dentistry, and Dental Research Institute, Seoul National University School of Dentistry, 101 Daehak-ro, Jongno-gu, Seoul 110-749 Republic of Korea.
| | - Keesung Kim
- Institute of Advanced Machinery & Design and School of Mechanical & Aerospace Engineering, Seoul National University, 599 Gwanak-ro, Gwanak-gu, Seoul 151-742, Republic of Korea.
| | - Sangho Roh
- Cellular Reprogramming & Embryo Biotechnology Laboratory, Seoul National University School of Dentistry, 101 Daehak-ro, Jongno-gu, Seoul 110-749, Republic of Korea.
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335
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González-Granado JM, Silvestre-Roig C, Rocha-Perugini V, Trigueros-Motos L, Cibrián D, Morlino G, Blanco-Berrocal M, Osorio FG, Freije JMP, López-Otín C, Sánchez-Madrid F, Andrés V. Nuclear envelope lamin-A couples actin dynamics with immunological synapse architecture and T cell activation. Sci Signal 2014; 7:ra37. [PMID: 24757177 DOI: 10.1126/scisignal.2004872] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
In many cell types, nuclear A-type lamins regulate multiple cellular functions, including higher-order genome organization, DNA replication and repair, gene transcription, and signal transduction; however, their role in specialized immune cells remains largely unexplored. We showed that the abundance of A-type lamins was almost negligible in resting naïve T lymphocytes, but was increased upon activation of the T cell receptor (TCR). The increase in lamin-A was an early event that accelerated formation of the immunological synapse between T cells and antigen-presenting cells. Polymerization of F-actin in T cells is a critical step for immunological synapse formation, and lamin-A interacted with the linker of nucleoskeleton and cytoskeleton (LINC) complex to promote F-actin polymerization. We also showed that lamin-A expression accelerated TCR clustering and led to enhanced downstream signaling, including extracellular signal-regulated kinase 1/2 (ERK1/2) signaling, as well as increased target gene expression. Pharmacological inhibition of the ERK pathway reduced lamin-A-dependent T cell activation. Moreover, mice lacking lamin-A in immune cells exhibited impaired T cell responses in vivo. These findings underscore the importance of A-type lamins for TCR activation and identify lamin-A as a previously unappreciated regulator of the immune response.
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Affiliation(s)
- José María González-Granado
- Department of Epidemiology, Atherothrombosis and Imaging, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Carlos Silvestre-Roig
- Department of Epidemiology, Atherothrombosis and Imaging, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Vera Rocha-Perugini
- Vascular Biology and Inflammation. CNIC, Madrid, Spain.,Servicio de Inmunología, Hospital de la Princesa, Instituto de Investigación Sanitaria Princesa, Madrid, Spain
| | - Laia Trigueros-Motos
- Department of Epidemiology, Atherothrombosis and Imaging, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Danay Cibrián
- Vascular Biology and Inflammation. CNIC, Madrid, Spain.,Servicio de Inmunología, Hospital de la Princesa, Instituto de Investigación Sanitaria Princesa, Madrid, Spain
| | - Giulia Morlino
- Vascular Biology and Inflammation. CNIC, Madrid, Spain.,Servicio de Inmunología, Hospital de la Princesa, Instituto de Investigación Sanitaria Princesa, Madrid, Spain
| | - Marta Blanco-Berrocal
- Department of Epidemiology, Atherothrombosis and Imaging, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Fernando Garcia Osorio
- Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo-IUOPA, Oviedo, Spain
| | | | - Carlos López-Otín
- Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo-IUOPA, Oviedo, Spain
| | - Francisco Sánchez-Madrid
- Vascular Biology and Inflammation. CNIC, Madrid, Spain.,Servicio de Inmunología, Hospital de la Princesa, Instituto de Investigación Sanitaria Princesa, Madrid, Spain
| | - Vicente Andrés
- Department of Epidemiology, Atherothrombosis and Imaging, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
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336
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Fabrikant G, Gupta S, Shivashankar GV, Kozlov MM. Model of T-cell nuclear deformation by the cortical actin layer. Biophys J 2014; 105:1316-23. [PMID: 24047982 DOI: 10.1016/j.bpj.2013.07.024] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 07/08/2013] [Accepted: 07/11/2013] [Indexed: 01/08/2023] Open
Abstract
Deformations of cell nuclei accompany a number of essential intracellular processes. Although evidence is being accumulated on the primary role actin structures play in controlling the shape of the nucleus, the mechanisms behind this phenomenon remain unknown. Here, we consider theoretically a specific paradigm of nuclear deformation, and a related actin rearrangement, in T cells stimulated by contact with a bead covered by surrogate antigens. We suggest that the nucleus is deformed by the elastic forces developed within a cylindrical layer of polymerized actin, which is generated as a result of the receptor-mediated T-cell activation. We substantiate this proposal with a theoretical analysis of mutual deformations in the actin layer and the nucleus, which recovers the experimentally observed nuclear shapes. Furthermore, we evaluate the forces developed by the actin polymerization that drives the nuclear deformation. The model predicts the mode of actin polymerization generated by the surrogate antigens covering a bead and the values of the elastic moduli of the nuclear shell. We provide a qualitative experimental support for the model assumptions by visualizing the stages of nuclear shape change and the corresponding evolution of the cortical actin.
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Affiliation(s)
- Gur Fabrikant
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel
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337
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Coiling and maturation of a high-performance fibre in hagfish slime gland thread cells. Nat Commun 2014; 5:3534. [PMID: 24698953 DOI: 10.1038/ncomms4534] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 03/04/2014] [Indexed: 01/07/2023] Open
Abstract
The defensive slime of hagfishes contains thousands of intermediate filament protein threads that are manufactured within specialized gland thread cells. The material properties of these threads rival those of spider dragline silks, which makes them an ideal model for biomimetic efforts to produce sustainable protein materials, yet how the thread is produced and organized within the cell is not well understood. Here we show how changes in nuclear morphology, size and position can explain the three-dimensional pattern of thread coiling in gland thread cells, and how the ultrastructure of the thread changes as very young thread cells develop into large cells with fully mature coiled threads. Our model provides an explanation for the complex process of thread assembly and organization that has fascinated and perplexed biologists for over a century, and provides valuable insights for the quest to manufacture high-performance biomimetic protein materials.
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338
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Luxton GWG, Starr DA. KASHing up with the nucleus: novel functional roles of KASH proteins at the cytoplasmic surface of the nucleus. Curr Opin Cell Biol 2014; 28:69-75. [PMID: 24704701 DOI: 10.1016/j.ceb.2014.03.002] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 03/05/2014] [Accepted: 03/08/2014] [Indexed: 10/25/2022]
Abstract
Nuclear-cytoskeletal connections are central to fundamental cellular processes, including nuclear positioning and chromosome movements in meiosis. The cytoskeleton is coupled to the nucleoskeleton through conserved KASH-SUN bridges, or LINC complexes, that span the nuclear envelope. KASH proteins localize to the outer nuclear membrane where they connect the nucleus to the cytoskeleton. New findings have expanded the functional diversity of KASH proteins, showing that they interact with microtubule motors, actin, intermediate filaments, a nonconventional myosin, RanGAP, and each other. The role of KASH proteins in cellular mechanics is discussed. Genetic mutations in KASH proteins are associated with autism, hearing loss, cancer, muscular dystrophy and other diseases.
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Affiliation(s)
- G W Gant Luxton
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, United States.
| | - Daniel A Starr
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, United States.
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339
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Spagnol ST, Weltz JS, Xue Y, Dahl KN. Mechanical Coupling of the Endothelial Cytoskeleton and Nucleus with VEGF Stimulation. Cell Mol Bioeng 2014. [DOI: 10.1007/s12195-014-0327-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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340
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Kiss A, Horvath P, Rothballer A, Kutay U, Csucs G. Nuclear motility in glioma cells reveals a cell-line dependent role of various cytoskeletal components. PLoS One 2014; 9:e93431. [PMID: 24691067 PMCID: PMC3972233 DOI: 10.1371/journal.pone.0093431] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 03/05/2014] [Indexed: 12/31/2022] Open
Abstract
Nuclear migration is a general term for the movement of the nucleus towards a specific site in the cell. These movements are involved in a number of fundamental biological processes, such as fertilization, cell division, and embryonic development. Despite of its importance, the mechanism of nuclear migration is still poorly understood in mammalian cells. In order to shed light on the mechanical processes underlying nuclear movements, we adapted a micro-patterning based assay. C6 rat and U87 human glioma cells seeded on fibronectin patterns - thereby forced into a bipolar morphology - displayed oscillatory movements of the nucleus or the whole cell, respectively. We found that both the actomyosin system and microtubules are involved in the nuclear/cellular movements of both cell lines, but their contributions are cell-/migration-type specific. Dynein activity was necessary for nuclear migration of C6 cells but active myosin-II was dispensable. On the other hand, coupled nuclear and cellular movements of U87 cells were driven by actomyosin contraction. We explain these cell-line dependent effects by the intrinsic differences in the overall mechanical tension due to the various cytoskeletal elements inside the cell. Our observations showed that the movements of the nucleus and the centrosome are strongly correlated and display large variation, indicating a tight but flexible coupling between them. The data also indicate that the forces responsible for nuclear movements are not acting directly via the centrosome. Based on our observations, we propose a new model for nuclear oscillations in C6 cells in which dynein and microtubule dynamics are the main drivers of nuclear movements. This mechanism is similar to the meiotic nuclear oscillations of Schizosaccharomyces pombe and may be evolutionary conserved.
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Affiliation(s)
- Alexa Kiss
- Institute of Biochemistry, ETH Zurich, Zurich, Switzerland; Light Microscopy and Screening Centre, ETH Zurich, Zurich, Switzerland
| | - Peter Horvath
- Institute of Biochemistry, ETH Zurich, Zurich, Switzerland; Light Microscopy and Screening Centre, ETH Zurich, Zurich, Switzerland
| | | | - Ulrike Kutay
- Institute of Biochemistry, ETH Zurich, Zurich, Switzerland
| | - Gabor Csucs
- Institute of Biochemistry, ETH Zurich, Zurich, Switzerland; Light Microscopy and Screening Centre, ETH Zurich, Zurich, Switzerland
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341
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Tadeo I, Berbegall AP, Escudero LM, Alvaro T, Noguera R. Biotensegrity of the extracellular matrix: physiology, dynamic mechanical balance, and implications in oncology and mechanotherapy. Front Oncol 2014; 4:39. [PMID: 24624363 PMCID: PMC3940942 DOI: 10.3389/fonc.2014.00039] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Accepted: 02/15/2014] [Indexed: 01/25/2023] Open
Abstract
Cells have the capacity to convert mechanical stimuli into chemical changes. This process is based on the tensegrity principle, a mechanism of tensional integrity. To date, this principle has been demonstrated to act in physiological processes such as mechanotransduction and mechanosensing at different scales (from cell sensing through integrins to molecular mechanical interventions or even localized massage). The process involves intra- and extracellular components, including the participation of extracellular matrix (ECM) and microtubules that act as compression structures, and actin filaments which act as tension structures. The nucleus itself has its own tensegrity system which is implicated in cell proliferation, differentiation, and apoptosis. Despite present advances, only the tip of the iceberg has so far been uncovered regarding the role of ECM compounds in influencing biotensegrity in pathological processes. Groups of cells, together with the surrounding ground substance, are subject to different and specific forces that certainly influence biological processes. In this paper, we review the current knowledge on the role of ECM elements in determining biotensegrity in malignant processes and describe their implication in therapeutic response, resistance to chemo- and radiotherapy, and subsequent tumor progression. Original data based on the study of neuroblastic tumors will be provided.
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Affiliation(s)
- Irene Tadeo
- Foundation INCLIVA, Hospital Clínico de Valencia , Valencia , Spain
| | - Ana P Berbegall
- Foundation INCLIVA, Hospital Clínico de Valencia , Valencia , Spain ; Department of Pathology, Medical School, University of Valencia , Valencia , Spain
| | - Luis M Escudero
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Departamento de Biología Celular de la Universidad de Sevilla , Seville , Spain
| | - Tomás Alvaro
- Department of Pathology, Hospital de Tortosa, Verge de la Cinta, IISPV, URV , Tortosa , Spain
| | - Rosa Noguera
- Department of Pathology, Medical School, University of Valencia , Valencia , Spain
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342
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Link J, Leubner M, Schmitt J, Göb E, Benavente R, Jeang KT, Xu R, Alsheimer M. Analysis of meiosis in SUN1 deficient mice reveals a distinct role of SUN2 in mammalian meiotic LINC complex formation and function. PLoS Genet 2014; 10:e1004099. [PMID: 24586178 PMCID: PMC3937131 DOI: 10.1371/journal.pgen.1004099] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Accepted: 11/25/2013] [Indexed: 11/30/2022] Open
Abstract
LINC complexes are evolutionarily conserved nuclear envelope bridges, composed of SUN (Sad-1/UNC-84) and KASH (Klarsicht/ANC-1/Syne/homology) domain proteins. They are crucial for nuclear positioning and nuclear shape determination, and also mediate nuclear envelope (NE) attachment of meiotic telomeres, essential for driving homolog synapsis and recombination. In mice, SUN1 and SUN2 are the only SUN domain proteins expressed during meiosis, sharing their localization with meiosis-specific KASH5. Recent studies have shown that loss of SUN1 severely interferes with meiotic processes. Absence of SUN1 provokes defective telomere attachment and causes infertility. Here, we report that meiotic telomere attachment is not entirely lost in mice deficient for SUN1, but numerous telomeres are still attached to the NE through SUN2/KASH5-LINC complexes. In Sun1−/− meiocytes attached telomeres retained the capacity to form bouquet-like clusters. Furthermore, we could detect significant numbers of late meiotic recombination events in Sun1−/− mice. Together, this indicates that even in the absence of SUN1 telomere attachment and their movement within the nuclear envelope per se can be functional. Correct genome haploidization during meiosis requires tightly regulated chromosome movements that follow a highly conserved choreography during prophase I. Errors in these movements cause subsequent meiotic defects, which typically lead to infertility. At the beginning of meiotic prophase, chromosome ends are tethered to the nuclear envelope (NE). This attachment of telomeres appears to be mediated by well-conserved membrane spanning protein complexes within the NE (LINC complexes). In mouse meiosis, the two main LINC components SUN1 and SUN2 were independently described to localize at the sites of telomere attachment. While SUN1 has been demonstrated to be critical for meiotic telomere attachment, the precise role of SUN2 in this context, however, has been discussed controversially in the field. Our current study was targeted to determine the factual capacity of SUN2 in telomere attachment and chromosome movements in SUN1 deficient mice. Remarkably, although telomere attachment is impaired in the absence of SUN1, we could find a yet undescribed SUN1-independent telomere attachment, which presumably is mediated by SUN2 and KASH5. This SUN2 mediated telomere attachment is stable throughout prophase I and functional in moving telomeres within the NE. Thus, our results clearly indicate that SUN1 and SUN2, at least partially, fulfill redundant meiotic functions.
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Affiliation(s)
- Jana Link
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Monika Leubner
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Johannes Schmitt
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Eva Göb
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Ricardo Benavente
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Kuan-Teh Jeang
- Molecular Virology Section, Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Rener Xu
- Institute of Developmental Biology and Molecular Medicine and School of Life Science, Fudan University, Shanghai, China
| | - Manfred Alsheimer
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
- * E-mail:
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343
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Gasiorowski JZ, Murphy CJ, Nealey PF. Biophysical cues and cell behavior: the big impact of little things. Annu Rev Biomed Eng 2014; 15:155-76. [PMID: 23862676 DOI: 10.1146/annurev-bioeng-071811-150021] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The extracellular matrix is composed of a variety of proteins, polysaccharides, and glycosaminoglycans that self-assemble into a hierarchical order of nanometer- to micrometer-scale fibrils and fibers. The shapes, sizes, and elasticity present within this highly ordered meshwork regulate behaviors in most cell types. It has been well documented that cellular migration, proliferation, differentiation, and tissue development are all influenced by matrix geometries and compliance, but how these external biophysical cues are translated into activated intracellular signaling cascades remains poorly understood. Fortunately, technological improvements in artificial substrate fabrication have provided biologists with tools to test cellular interactions within controlled three-dimensional environments. Here, we review cellular responses to biophysical cues and discuss their clinical relevancy and application. We focus especially on integrative approaches that aim to first characterize the properties of specific extracellular matrices and then precisely fabricate biomimetic materials to elucidate how relevant cells respond to the individual biophysical cues present in their native tissues. Through these types of comprehensive studies, biologists have begun to understand and appreciate how exceedingly small features can have a significant impact on the regulation, development, and homeostasis of cells and tissues.
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Affiliation(s)
- Joshua Z Gasiorowski
- Department of Biomedical Sciences, Midwestern University, Downers Grove, IL 60515, USA
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344
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Genome-wide analysis links emerin to neuromuscular junction activity in Caenorhabditis elegans. Genome Biol 2014; 15:R21. [PMID: 24490688 PMCID: PMC4053756 DOI: 10.1186/gb-2014-15-2-r21] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 02/03/2014] [Indexed: 01/01/2023] Open
Abstract
Background Laminopathies are diseases characterized by defects in nuclear envelope structure. A well-known example is Emery-Dreifuss muscular dystrophy, which is caused by mutations in the human lamin A/C and emerin genes. While most nuclear envelope proteins are ubiquitously expressed, laminopathies often affect only a subset of tissues. The molecular mechanisms underlying these tissue-specific manifestations remain elusive. We hypothesize that different functional subclasses of genes might be differentially affected by defects in specific nuclear envelope components. Results Here we determine genome-wide DNA association profiles of two nuclear envelope components, lamin/LMN-1 and emerin/EMR-1 in adult Caenorhabditis elegans. Although both proteins bind to transcriptionally inactive regions of the genome, EMR-1 is enriched at genes involved in muscle and neuronal function. Deletion of either EMR-1 or LEM-2, another integral envelope protein, causes local changes in nuclear architecture as evidenced by altered association between DNA and LMN-1. Transcriptome analyses reveal that EMR-1 and LEM-2 are associated with gene repression, particularly of genes implicated in muscle and nervous system function. We demonstrate that emr-1, but not lem-2, mutants are sensitive to the cholinesterase inhibitor aldicarb, indicating altered activity at neuromuscular junctions. Conclusions We identify a class of elements that bind EMR-1 but do not associate with LMN-1, and these are enriched for muscle and neuronal genes. Our data support a redundant function of EMR-1 and LEM-2 in chromatin anchoring to the nuclear envelope and gene repression. We demonstrate a specific role of EMR-1 in neuromuscular junction activity that may contribute to Emery-Dreifuss muscular dystrophy in humans.
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345
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Nagayama K, Yamazaki S, Yahiro Y, Matsumoto T. Estimation of the mechanical connection between apical stress fibers and the nucleus in vascular smooth muscle cells cultured on a substrate. J Biomech 2014; 47:1422-9. [PMID: 24548337 DOI: 10.1016/j.jbiomech.2014.01.042] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 01/17/2014] [Accepted: 01/18/2014] [Indexed: 11/26/2022]
Abstract
Actin stress fibers (SFs) generate intercellular tension and play important roles in cellular mechanotransduction processes and the regulation of various cellular functions. We recently found, in vascular smooth muscle cells (SMCs) cultured on a substrate, that the apical SFs running across the top surface of the nucleus have a mechanical connection with the cell nucleus and that their internal tension is transmitted directly to the nucleus. However, the effects of the connecting conditions and binding forces between SFs and the nucleus on force transmission processes are unclear at this stage. Here, we estimated the mechanical connection between apical SFs and the nucleus in SMCs, taking into account differences in the contractility of individual SFs, using experimental and numerical approaches. First, we classified apical SFs in SMCs according to their morphological characteristics: one subset appeared pressed onto the apical surface of the nucleus (pressed SFs), and the other appeared to be smoothly attached to the nuclear surface (attached SFs). We then dissected these SFs by laser irradiation to release the pretension, observed the dynamic behavior of the dissected SFs and the nucleus, and estimated the pretension of the SFs and the connection strength between the SFs and the nucleus by using a simple viscoelastic model. We found that pressed SFs generated greater contractile force and were more firmly connected to the nuclear surface than were attached SFs. We also observed line-like concentration of the nuclear membrane protein nesprin 1 and perinuclear DNA that was significantly located along the pressed SFs. These results indicate that the internal tension of pressed SFs is transmitted to the nucleus more efficiently than that of attached SFs, and that pressed SFs have significant roles in the regulation of the nuclear morphology and rearrangement of intranuclear DNA.
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Affiliation(s)
- Kazuaki Nagayama
- Biomechanics Laboratory, Department of Mechanical Engineering, Nagoya Institute of Technology, Omohi College, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan.
| | - Sho Yamazaki
- Biomechanics Laboratory, Department of Mechanical Engineering, Nagoya Institute of Technology, Omohi College, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
| | - Yuki Yahiro
- Biomechanics Laboratory, Department of Mechanical Engineering, Nagoya Institute of Technology, Omohi College, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
| | - Takeo Matsumoto
- Biomechanics Laboratory, Department of Mechanical Engineering, Nagoya Institute of Technology, Omohi College, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan.
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346
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Razafsky D, Wirtz D, Hodzic D. Nuclear envelope in nuclear positioning and cell migration. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 773:471-90. [PMID: 24563361 PMCID: PMC4310828 DOI: 10.1007/978-1-4899-8032-8_21] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Hauling and anchoring the nucleus within immobile or motile cells, tissues, and/or syncytia represents a major challenge. In the past 15 years, Linkers of the Nucleoskeleton to the Cytoskeleton (LINC complexes) have emerged as evolutionary-conserved molecular devices that span the nuclear envelope and provide interacting interfaces for cytoskeletal networks and molecular motors to the nuclear envelope. Here, we review the molecular composition of LINC complexes and focus on how their genetic alteration in vivo has provided a wealth of information related to the relevance of nuclear positioning during tissue development and homeostasis with a special emphasis on the central nervous system. As it may be relevant for metastasis in a range of cancers, the involvement of LINC complexes in migration of nonneuronal cells via its interaction with the perinuclear actin cap will also be developed.
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Affiliation(s)
- David Razafsky
- Washington University School of Medicine, Department of Ophthalmology and Visual Sciences, 660 South Euclid Ave, St Louis, MO, 63110, USA
| | - Denis Wirtz
- The Johns Hopkins University, Department of Chemical and Biomolecular engineering, 3400 North Charles St., Baltimore, MD, 21218, USA
| | - Didier Hodzic
- Washington University School of Medicine, Department of Ophthalmology and Visual Sciences, 660 South Euclid Ave, St Louis, MO, 63110, USA
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347
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Jahed Z, Shams H, Mehrbod M, Mofrad MRK. Mechanotransduction pathways linking the extracellular matrix to the nucleus. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2014; 310:171-220. [PMID: 24725427 DOI: 10.1016/b978-0-12-800180-6.00005-0] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Cells contain several mechanosensing components that transduce mechanical signals into biochemical cascades. During cell-ECM adhesion, a complex network of molecules mechanically couples the extracellular matrix (ECM), cytoskeleton, and nucleoskeleton. The network comprises transmembrane receptor proteins and focal adhesions, which link the ECM and cytoskeleton. Additionally, recently identified protein complexes extend this linkage to the nucleus by linking the cytoskeleton and the nucleoskeleton. Despite numerous studies in this field, due to the complexity of this network, our knowledge of the mechanisms of cell-ECM adhesion at the molecular level remains remarkably incomplete. Herein, we present a review of the structures of key molecules involved in cell-ECM adhesion, along with an evaluation of their predicted roles in mechanical sensing. Additionally, specific binding events prompted by force-induced conformational changes of each molecule are discussed. Finally, we propose a model for the biomechanical events prominent in cell-ECM adhesion.
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Affiliation(s)
- Zeinab Jahed
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California at Berkeley, Berkeley, California, USA
| | - Hengameh Shams
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California at Berkeley, Berkeley, California, USA
| | - Mehrdad Mehrbod
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California at Berkeley, Berkeley, California, USA
| | - Mohammad R K Mofrad
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California at Berkeley, Berkeley, California, USA.
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348
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Kaminski A, Fedorchak GR, Lammerding J. The cellular mastermind(?)-mechanotransduction and the nucleus. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 126:157-203. [PMID: 25081618 PMCID: PMC4591053 DOI: 10.1016/b978-0-12-394624-9.00007-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cells respond to mechanical stimulation by activation of specific signaling pathways and genes that allow the cell to adapt to its dynamic physical environment. How cells sense the various mechanical inputs and translate them into biochemical signals remains an area of active investigation. Recent reports suggest that the cell nucleus may be directly implicated in this cellular mechanotransduction process. Taken together, these findings paint a picture of the nucleus as a central hub in cellular mechanotransduction-both structurally and biochemically-with important implications in physiology and disease.
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Affiliation(s)
- Ashley Kaminski
- Department of Biomedical Engineering & Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York, USA
| | - Gregory R Fedorchak
- Department of Biomedical Engineering & Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York, USA
| | - Jan Lammerding
- Department of Biomedical Engineering & Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York, USA
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349
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Abstract
Despite decades of research, cancer metastasis remains an incompletely understood process that is as complex as it is devastating. In recent years, there has been an increasing push to investigate the biomechanical aspects of tumorigenesis, complementing the research on genetic and biochemical changes. In contrast to the high genetic variability encountered in cancer cells, almost all metastatic cells are subject to the same physical constraints as they leave the primary tumor, invade surrounding tissues, transit through the circulatory system, and finally infiltrate new tissues. Advances in live cell imaging and other biophysical techniques, including measurements of subcellular mechanics, have yielded stunning new insights into the physics of cancer cells. While much of this research has been focused on the mechanics of the cytoskeleton and the cellular microenvironment, it is now emerging that the mechanical properties of the cell nucleus and its connection to the cytoskeleton may play a major role in cancer metastasis, as deformation of the large and stiff nucleus presents a substantial obstacle during the passage through the dense interstitial space and narrow capillaries. Here, we present an overview of the molecular components that govern the mechanical properties of the nucleus, and we discuss how changes in nuclear structure and composition observed in many cancers can modulate nuclear mechanics and promote metastatic processes. Improved insights into this interplay between nuclear mechanics and metastatic progression may have powerful implications in cancer diagnostics and therapy and may reveal novel therapeutic targets for pharmacological inhibition of cancer cell invasion.
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Affiliation(s)
- Celine Denais
- Department of Biomedical Engineering, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, 14853, USA,
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350
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Neumann S, Noegel AA. Nesprins in Cell Stability and Migration. CANCER BIOLOGY AND THE NUCLEAR ENVELOPE 2014; 773:491-504. [DOI: 10.1007/978-1-4899-8032-8_22] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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