1
|
Attar AG, Paturej J, Banigan EJ, Erbaş A. Chromatin phase separation and nuclear shape fluctuations are correlated in a polymer model of the nucleus. Nucleus 2024; 15:2351957. [PMID: 38753956 PMCID: PMC11407394 DOI: 10.1080/19491034.2024.2351957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 04/22/2024] [Accepted: 04/28/2024] [Indexed: 05/18/2024] Open
Abstract
Abnormal cell nuclear shapes are hallmarks of diseases, including progeria, muscular dystrophy, and many cancers. Experiments have shown that disruption of heterochromatin and increases in euchromatin lead to nuclear deformations, such as blebs and ruptures. However, the physical mechanisms through which chromatin governs nuclear shape are poorly understood. To investigate how heterochromatin and euchromatin might govern nuclear morphology, we studied chromatin microphase separation in a composite coarse-grained polymer and elastic shell simulation model. By varying chromatin density, heterochromatin composition, and heterochromatin-lamina interactions, we show how the chromatin phase organization may perturb nuclear shape. Increasing chromatin density stabilizes the lamina against large fluctuations. However, increasing heterochromatin levels or heterochromatin-lamina interactions enhances nuclear shape fluctuations by a "wetting"-like interaction. In contrast, fluctuations are insensitive to heterochromatin's internal structure. Our simulations suggest that peripheral heterochromatin accumulation could perturb nuclear morphology, while nuclear shape stabilization likely occurs through mechanisms other than chromatin microphase organization.
Collapse
Affiliation(s)
- Ali Goktug Attar
- UNAM-National Nanotechnology Research Center and Institute of Materials Science & Nanotechnology, Bilkent University, Ankara, Turkey
| | | | - Edward J Banigan
- Institute for Medical Engineering and Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Aykut Erbaş
- UNAM-National Nanotechnology Research Center and Institute of Materials Science & Nanotechnology, Bilkent University, Ankara, Turkey
- Institute of Physics, University of Silesia, Chorzów, Poland
| |
Collapse
|
2
|
Vizjak P, Kamp D, Hepp N, Scacchetti A, Gonzalez Pisfil M, Bartho J, Halic M, Becker PB, Smolle M, Stigler J, Mueller-Planitz F. ISWI catalyzes nucleosome sliding in condensed nucleosome arrays. Nat Struct Mol Biol 2024; 31:1331-1340. [PMID: 38664566 DOI: 10.1038/s41594-024-01290-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 03/25/2024] [Indexed: 05/07/2024]
Abstract
How chromatin enzymes work in condensed chromatin and how they maintain diffusional mobility inside remains unexplored. Here we investigated these challenges using the Drosophila ISWI remodeling ATPase, which slides nucleosomes along DNA. Folding of chromatin fibers did not affect sliding in vitro. Catalytic rates were also comparable in- and outside of chromatin condensates. ISWI cross-links and thereby stiffens condensates, except when ATP hydrolysis is possible. Active hydrolysis is also required for ISWI's mobility in condensates. Energy from ATP hydrolysis therefore fuels ISWI's diffusion through chromatin and prevents ISWI from cross-linking chromatin. Molecular dynamics simulations of a 'monkey-bar' model in which ISWI grabs onto neighboring nucleosomes, then withdraws from one before rebinding another in an ATP hydrolysis-dependent manner, qualitatively agree with our data. We speculate that monkey-bar mechanisms could be shared with other chromatin factors and that changes in chromatin dynamics caused by mutations in remodelers could contribute to pathologies.
Collapse
Affiliation(s)
- Petra Vizjak
- Institute of Physiological Chemistry, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
- Department of Molecular Biology, Biomedical Center, Faculty of Medicine, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
- Early Stage Bioprocess Development, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Dieter Kamp
- Gene Center, Department of Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Nicola Hepp
- Institute of Physiological Chemistry, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
- Department of Molecular Biology, Biomedical Center, Faculty of Medicine, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
- Department of Clinical Genetics, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Alessandro Scacchetti
- Department of Molecular Biology, Biomedical Center, Faculty of Medicine, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
- Epigenetics Institute and Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Mariano Gonzalez Pisfil
- Core Facility Bioimaging and Walter-Brendel-Centre of Experimental Medicine, Biomedical Center, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Joseph Bartho
- Gene Center, Department of Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany
- European Molecular Biology Laboratory, Heidelberg, Germany
| | - Mario Halic
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Peter B Becker
- Department of Molecular Biology, Biomedical Center, Faculty of Medicine, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Michaela Smolle
- Department of Physiological Chemistry, Biomedical Center, Faculty of Medicine, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
- BioPhysics Core Facility, Biomedical Center, Faculty of Medicine, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
- ViraTherapeutics GmbH, Rum, Austria
| | - Johannes Stigler
- Gene Center, Department of Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany.
| | - Felix Mueller-Planitz
- Institute of Physiological Chemistry, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.
| |
Collapse
|
3
|
Stephens RK, Miroshnikova YA. Nuclear periphery and its mechanical regulation in cell fate transitions. Curr Opin Struct Biol 2024; 87:102867. [PMID: 38889500 DOI: 10.1016/j.sbi.2024.102867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 05/22/2024] [Accepted: 05/27/2024] [Indexed: 06/20/2024]
Abstract
Cell fate changes require rewiring of transcriptional programs to generate functionally specialized cell states. Reconfiguration of transcriptional networks requires overcoming epigenetic barriers imposed by silenced heterochromatin in order to activate lineage-specific genes. Further, cell fate decisions are made in a tissue-specific context, where cells are physically linked to each other as well as to the connective tissue environment. Here, cells are continuously exposed to a multitude of mechanical forces emanating from cellular dynamics in their local microenvironments, for example through cell movements, cell divisions, tissue contractions, or fluid flow. Through their ability to deform cellular structures and activate receptors, mechanical forces can be sensed at the plasma membrane, but also at the nuclear periphery through direct or cytoskeleton-mediated deformation of the nuclear envelope. This deformation and the associated signaling is capable of triggering changes in the mechanical state of the nuclear membranes, the organization and rigidity of the underlying nuclear lamina, compaction state of chromatin, and ultimately transcription. This review focuses on the role of nuclear architecture, particularly the nuclear lamina-chromatin interface, and its mechanical regulation in cell fate decisions as well as its physiological role in development and cellular reprogramming.
Collapse
Affiliation(s)
- Rebecca K Stephens
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA. https://twitter.com/BecKateStephens
| | - Yekaterina A Miroshnikova
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.
| |
Collapse
|
4
|
Semeigazin A, Iida S, Minami K, Tamura S, Ide S, Higashi K, Toyoda A, Kurokawa K, Maeshima K. Behaviors of nucleosomes with mutant histone H4s in euchromatic domains of living human cells. Histochem Cell Biol 2024; 162:23-40. [PMID: 38743310 DOI: 10.1007/s00418-024-02293-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/21/2024] [Indexed: 05/16/2024]
Abstract
Since Robert Feulgen first stained DNA in the cell, visualizing genome chromatin has been a central issue in cell biology to uncover how chromatin is organized and behaves in the cell. To approach this issue, we have developed single-molecule imaging of nucleosomes, a basic unit of chromatin, to unveil local nucleosome behavior in living cells. In this study, we investigated behaviors of nucleosomes with various histone H4 mutants in living HeLa cells to address the role of H4 tail acetylation, including H4K16Ac and others, which are generally associated with more transcriptionally active chromatin regions. We ectopically expressed wild-type (wt) or mutated H4s (H4K16 point; H4K5,8,12,16 quadruple; and H4 tail deletion) fused with HaloTag in HeLa cells. Cells that expressed wtH4-Halo, H4K16-Halo mutants, and multiple H4-Halo mutants had euchromatin-concentrated distribution. Consistently, the genomic regions of the wtH4-Halo nucleosomes corresponded to Hi-C contact domains (or topologically associating domains, TADs) with active chromatin marks (A-compartment). Utilizing single-nucleosome imaging, we found that none of the H4 deacetylation or acetylation mimicked H4 mutants altered the overall local nucleosome motion. This finding suggests that H4 mutant nucleosomes embedded in the condensed euchromatic domains with excess endogenous H4 nucleosomes cannot cause an observable change in the local motion. Interestingly, H4 with four lysine-to-arginine mutations displayed a substantial freely diffusing fraction in the nucleoplasm, whereas H4 with a truncated N-terminal tail was incorporated in heterochromatic regions as well as euchromatin. Our study indicates the power of single-nucleosome imaging to understand individual histone/nucleosome behavior reflecting chromatin environments in living cells.
Collapse
Affiliation(s)
- Adilgazy Semeigazin
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, 411-8540, Japan
| | - Shiori Iida
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, 411-8540, Japan
| | - Katsuhiko Minami
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, 411-8540, Japan
| | - Sachiko Tamura
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
| | - Satoru Ide
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, 411-8540, Japan
| | - Koichi Higashi
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, 411-8540, Japan
- Genome Evolution Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
| | - Atsushi Toyoda
- Comparative Genomics Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
| | - Ken Kurokawa
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, 411-8540, Japan
- Genome Evolution Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
| | - Kazuhiro Maeshima
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan.
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, 411-8540, Japan.
| |
Collapse
|
5
|
Hashimoto K, Ohira M, Kodama A, Kimoto M, Inoue M, Toné S, Usui Y, Hanashima A, Goto T, Ogura Y, Ujihara Y, Mohri S. Loss of connectin novex-3 leads to heart dysfunction associated with impaired cardiomyocyte proliferation and abnormal nuclear mechanics. Sci Rep 2024; 14:13727. [PMID: 38877142 PMCID: PMC11178842 DOI: 10.1038/s41598-024-64608-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 06/11/2024] [Indexed: 06/16/2024] Open
Abstract
Connectin (also known as titin) is a giant striated muscle protein that functions as a molecular spring by providing elasticity to the sarcomere. Novex-3 is a short splice variant of connectin whose physiological function remains unknown. We have recently demonstrated using in vitro analyses that in addition to sarcomere expression, novex-3 was also expressed in cardiomyocyte nuclei exclusively during fetal life, where it provides elasticity/compliance to cardiomyocyte nuclei and promotes cardiomyocyte proliferation in the fetus, suggesting a non-sarcomeric function. Here, we analyzed novex-3 knockout mice to assess the involvement of this function in cardiac pathophysiology in vivo. Deficiency of novex-3 compromised fetal cardiomyocyte proliferation and induced the enlargement of individual cardiomyocytes in neonates. In adults, novex-3 deficiency resulted in chamber dilation and systolic dysfunction, associated with Ca2+ dysregulation, resulting in a reduced life span. Mechanistic analyses revealed a possible association between impaired proliferation and abnormal nuclear mechanics, including stiffer nuclei positioned peripherally with stabilized circumnuclear microtubules in knockout cardiomyocytes. Although the underlying causal relationships were not fully elucidated, these data show that novex-3 has a vital non-sarcomeric function in cardiac pathophysiology and serves as an early contributor to cardiomyocyte proliferation.
Collapse
Affiliation(s)
- Ken Hashimoto
- First Department of Physiology, Kawasaki Medical School, Kurashiki, 701-0192, Japan.
| | - Momoko Ohira
- First Department of Physiology, Kawasaki Medical School, Kurashiki, 701-0192, Japan
| | - Aya Kodama
- First Department of Physiology, Kawasaki Medical School, Kurashiki, 701-0192, Japan
| | - Misaki Kimoto
- First Department of Physiology, Kawasaki Medical School, Kurashiki, 701-0192, Japan
| | - Mariko Inoue
- Central Research Institute, Kawasaki Medical School, Kurashiki, 701-0192, Japan
| | - Shigenobu Toné
- Laboratory of Molecular Developmental Biology, Graduate School of Science and Engineering, Tokyo Denki University, Hatoyama, Saitama, 350-0394, Japan
| | - Yuu Usui
- First Department of Physiology, Kawasaki Medical School, Kurashiki, 701-0192, Japan
| | - Akira Hanashima
- First Department of Physiology, Kawasaki Medical School, Kurashiki, 701-0192, Japan
| | - Takato Goto
- Department of Electrical and Mechanical Engineering, Nagoya Institute of Technology, Nagoya, 466-8555, Japan
| | - Yuhei Ogura
- Department of Electrical and Mechanical Engineering, Nagoya Institute of Technology, Nagoya, 466-8555, Japan
| | - Yoshihiro Ujihara
- Department of Electrical and Mechanical Engineering, Nagoya Institute of Technology, Nagoya, 466-8555, Japan
| | - Satoshi Mohri
- First Department of Physiology, Kawasaki Medical School, Kurashiki, 701-0192, Japan
| |
Collapse
|
6
|
Otsuka A, Minami K, Higashi K, Kawaguchi A, Tamura S, Ide S, Hendzel MJ, Kurokawa K, Maeshima K. Chromatin organization and behavior in HRAS-transformed mouse fibroblasts. Chromosoma 2024; 133:135-148. [PMID: 38400910 DOI: 10.1007/s00412-024-00817-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Revised: 01/24/2024] [Accepted: 02/05/2024] [Indexed: 02/26/2024]
Abstract
In higher eukaryotic cells, a string of nucleosomes, where long genomic DNA is wrapped around core histones, are rather irregularly folded into a number of condensed chromatin domains, which have been revealed by super-resolution imaging and Hi-C technologies. Inside these domains, nucleosomes fluctuate and locally behave like a liquid. The behavior of chromatin may be highly related to DNA transaction activities such as transcription and repair, which are often upregulated in cancer cells. To investigate chromatin behavior in cancer cells and compare those of cancer and non-cancer cells, we focused on oncogenic-HRAS (Gly12Val)-transformed mouse fibroblasts CIRAS-3 cells and their parental 10T1/2 cells. CIRAS-3 cells are tumorigenic and highly metastatic. First, we found that HRAS-induced transformation altered not only chromosome structure, but also nuclear morphology in the cell. Using single-nucleosome imaging/tracking in live cells, we demonstrated that nucleosomes are locally more constrained in CIRAS-3 cells than in 10T1/2 cells. Consistently, heterochromatin marked with H3K27me3 was upregulated in CIRAS-3 cells. Finally, Hi-C analysis showed enriched interactions of the B-B compartment in CIRAS-3 cells, which likely represents transcriptionally inactive chromatin. Increased heterochromatin may play an important role in cell migration, as they have been reported to increase during metastasis. Our study also suggests that single-nucleosome imaging provides new insights into how local chromatin is structured in living cells.
Collapse
Affiliation(s)
- Aoi Otsuka
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, 411-8540, Japan
| | - Katsuhiko Minami
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, 411-8540, Japan
| | - Koichi Higashi
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, 411-8540, Japan
- Genome Evolution Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
| | - Akane Kawaguchi
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, 411-8540, Japan
- Molecular Life History Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
| | - Sachiko Tamura
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
| | - Satoru Ide
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, 411-8540, Japan
| | - Michael J Hendzel
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
- Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Ken Kurokawa
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, 411-8540, Japan
- Genome Evolution Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
| | - Kazuhiro Maeshima
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan.
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, 411-8540, Japan.
| |
Collapse
|
7
|
Ma T, Liu X, Su H, Shi Q, He Y, Wu F, Gao C, Li K, Liang Z, Zhang D, Zhang X, Hu K, Li S, Wang L, Wang M, Yue S, Hong W, Chen X, Zhang J, Zheng L, Deng X, Wang P, Fan Y. Coupling of Perinuclear Actin Cap and Nuclear Mechanics in Regulating Flow-Induced Yap Spatiotemporal Nucleocytoplasmic Transport. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2305867. [PMID: 38161226 PMCID: PMC10953556 DOI: 10.1002/advs.202305867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Revised: 11/10/2023] [Indexed: 01/03/2024]
Abstract
Mechanical forces, including flow shear stress, govern fundamental cellular processes by modulating nucleocytoplasmic transport of transcription factors like Yes-associated Protein (YAP). However, the underlying mechanical mechanism remains elusive. In this study, it is reported that unidirectional flow induces biphasic YAP transport with initial nuclear import, followed by nuclear export as actin cap formation and nuclear stiffening. Conversely, pathological oscillatory flow induces slight actin cap formation, nuclear softening, and sustained YAP nuclear localization. To elucidate the disparately YAP spatiotemporal distribution, a 3D mechanochemical model is developed, which integrates flow sensing, cytoskeleton organization, nucleus mechanotransduction, and YAP transport. The results unveiled that despite the significant localized nuclear stress imposed by the actin cap, its inherent stiffness counteracts the dispersed contractile stress exerted by conventional fibers on the nuclear membrane. Moreover, alterations in nuclear stiffness synergistically regulate nuclear deformation, thereby governing YAP transport. Furthermore, by expanding the single-cell model to a collective vertex framework, it is revealed that the irregularities in actin cap formation within individual cells have the potential to induce topological defects and spatially heterogeneous YAP distribution in the cellular monolayer. This work unveils a unified mechanism of flow-induced nucleocytoplasmic transport, providing a linkage between transcription factor localization and mechanical stimulation.
Collapse
Affiliation(s)
- Tianxiang Ma
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical EngineeringBeihang UniversityBeijing100083China
| | - Xiao Liu
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical EngineeringBeihang UniversityBeijing100083China
| | - Haoran Su
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical EngineeringBeihang UniversityBeijing100083China
| | - Qiusheng Shi
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical EngineeringBeihang UniversityBeijing100083China
| | - Yuan He
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical EngineeringBeihang UniversityBeijing100083China
| | - Fan Wu
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical EngineeringBeihang UniversityBeijing100083China
| | - Chenxing Gao
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical EngineeringBeihang UniversityBeijing100083China
| | - Kexin Li
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical EngineeringBeihang UniversityBeijing100083China
| | - Zhuqing Liang
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical EngineeringBeihang UniversityBeijing100083China
| | - Dongrui Zhang
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical EngineeringBeihang UniversityBeijing100083China
| | - Xing Zhang
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical EngineeringBeihang UniversityBeijing100083China
| | - Ke Hu
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical EngineeringBeihang UniversityBeijing100083China
| | - Shangyu Li
- Biomedical Pioneering Innovation Center (BIOPIC)Peking UniversityBeijing100871China
- Academy for Advanced Interdisciplinary StudiesPeking UniversityBeijing100871China
| | - Li Wang
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical EngineeringBeihang UniversityBeijing100083China
| | - Min Wang
- Department of Gynecology and ObstetricsStrategic Support Force Medical CenterBeijing100101China
| | - Shuhua Yue
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical EngineeringBeihang UniversityBeijing100083China
| | - Weili Hong
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical EngineeringBeihang UniversityBeijing100083China
| | - Xun Chen
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical EngineeringBeihang UniversityBeijing100083China
| | - Jing Zhang
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical EngineeringBeihang UniversityBeijing100083China
| | - Lisha Zheng
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical EngineeringBeihang UniversityBeijing100083China
| | - Xiaoyan Deng
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical EngineeringBeihang UniversityBeijing100083China
| | - Pu Wang
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical EngineeringBeihang UniversityBeijing100083China
| | - Yubo Fan
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical EngineeringBeihang UniversityBeijing100083China
- School of Engineering MedicineBeihang UniversityBeijing100083China
| |
Collapse
|
8
|
Yamamoto-Hino M, Ariura M, Tanaka M, Iwasaki YW, Kawaguchi K, Shimamoto Y, Goto S. PIGB maintains nuclear lamina organization in skeletal muscle of Drosophila. J Cell Biol 2024; 223:e202301062. [PMID: 38261271 PMCID: PMC10808031 DOI: 10.1083/jcb.202301062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 10/09/2023] [Accepted: 11/17/2023] [Indexed: 01/24/2024] Open
Abstract
The nuclear lamina (NL) plays various roles and participates in nuclear integrity, chromatin organization, and transcriptional regulation. Lamin proteins, the main components of the NL, form a homogeneous meshwork structure under the nuclear envelope. Lamins are essential, but it is unknown whether their homogeneous distribution is important for nuclear function. Here, we found that PIGB, an enzyme involved in glycosylphosphatidylinositol (GPI) synthesis, is responsible for the homogeneous lamin meshwork in Drosophila. Loss of PIGB resulted in heterogeneous distributions of B-type lamin and lamin-binding proteins in larval muscles. These phenotypes were rescued by expression of PIGB lacking GPI synthesis activity. The PIGB mutant exhibited changes in lamina-associated domains that are large heterochromatic genomic regions in the NL, reduction of nuclear stiffness, and deformation of muscle fibers. These results suggest that PIGB maintains the homogeneous meshwork of the NL, which may be essential for chromatin distribution and nuclear mechanical properties.
Collapse
Affiliation(s)
- Miki Yamamoto-Hino
- Department of Life Science, College of Science, Rikkyo University, Tokyo, Japan
| | - Masaru Ariura
- Department of Molecular Biology, Keio University School of Medicine, Tokyo, Japan
| | - Masahito Tanaka
- Department of Chromosome Science, National Institute of Genetics, Mishima, Japan
| | - Yuka W. Iwasaki
- Department of Molecular Biology, Keio University School of Medicine, Tokyo, Japan
- Laboratory for Functional Non-Coding Genomics, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
- Japan Science and Technology Agency (JST), Precursory Research for Embryonic Science and Technology (PRESTO), Saitama, Japan
| | - Kohei Kawaguchi
- Department of Life Science, College of Science, Rikkyo University, Tokyo, Japan
| | - Yuta Shimamoto
- Department of Chromosome Science, National Institute of Genetics, Mishima, Japan
| | - Satoshi Goto
- Department of Life Science, College of Science, Rikkyo University, Tokyo, Japan
| |
Collapse
|
9
|
Pho M, Berrada Y, Gunda A, Lavallee A, Chiu K, Padam A, Currey ML, Stephens AD. Actin contraction controls nuclear blebbing and rupture independent of actin confinement. Mol Biol Cell 2024; 35:ar19. [PMID: 38088876 PMCID: PMC10881147 DOI: 10.1091/mbc.e23-07-0292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 11/03/2023] [Accepted: 11/27/2023] [Indexed: 01/14/2024] Open
Abstract
The nucleus is a mechanically stable compartment of the cell that contains the genome and performs many essential functions. Nuclear mechanical components chromatin and lamins maintain nuclear shape, compartmentalization, and function by resisting antagonistic actin contraction and confinement. Studies have yet to compare chromatin and lamins perturbations side-by-side as well as modulated actin contraction while holding confinement constant. To accomplish this, we used nuclear localization signal green fluorescent protein to measure nuclear shape and rupture in live cells with chromatin and lamin perturbations. We then modulated actin contraction while maintaining actin confinement measured by nuclear height. Wild type, chromatin decompaction, and lamin B1 null present bleb-based nuclear deformations and ruptures dependent on actin contraction and independent of actin confinement. Actin contraction inhibition by Y27632 decreased nuclear blebbing and ruptures while activation by CN03 increased rupture frequency. Lamin A/C null results in overall abnormal shape also reliant on actin contraction, but similar blebs and ruptures as wild type. Increased DNA damage is caused by nuclear blebbing or abnormal shape which can be relieved by inhibition of actin contraction which rescues nuclear shape and decreases DNA damage levels in all perturbations. Thus, actin contraction drives nuclear blebbing, bleb-based ruptures, and abnormal shape independent of changes in actin confinement.
Collapse
Affiliation(s)
- Mai Pho
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003
| | - Yasmin Berrada
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003
| | - Aachal Gunda
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003
| | - Anya Lavallee
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003
| | - Katherine Chiu
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003
| | - Arimita Padam
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003
| | - Marilena L. Currey
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003
| | - Andrew D. Stephens
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003
- Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA 01003
| |
Collapse
|
10
|
Attar AG, Paturej J, Banigan EJ, Erbas A. Chromatin phase separation and nuclear shape fluctuations are correlated in a polymer model of the nucleus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.16.571697. [PMID: 38168411 PMCID: PMC10760070 DOI: 10.1101/2023.12.16.571697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Abnormalities in the shapes of mammalian cell nuclei are hallmarks of a variety of diseases, including progeria, muscular dystrophy, and various cancers. Experiments have shown that there is a causal relationship between chromatin organization and nuclear morphology. Decreases in heterochromatin levels, perturbations to heterochromatin organization, and increases in euchromatin levels all lead to misshapen nuclei, which exhibit deformations, such as nuclear blebs and nuclear ruptures. However, the polymer physical mechanisms of how chromatin governs nuclear shape and integrity are poorly understood. To investigate how heterochromatin and euchromatin, which are thought to microphase separate in vivo , govern nuclear morphology, we implemented a composite coarse-grained polymer and elastic shell model. By varying chromatin volume fraction (density), heterochromatin levels and structure, and heterochromatin-lamina interactions, we show how the spatial organization of chromatin polymer phases within the nucleus could perturb nuclear shape in some scenarios. Increasing the volume fraction of chromatin in the cell nucleus stabilizes the nuclear lamina against large fluctuations. However, surprisingly, we find that increasing heterochromatin levels or heterochromatin-lamina interactions enhances nuclear shape fluctuations in our simulations by a "wetting"-like interaction. In contrast, shape fluctuations are largely insensitive to the internal structure of the heterochromatin, such as the presence or absence of chromatin-chromatin crosslinks. Therefore, our simulations suggest that heterochromatin accumulation at the nuclear periphery could perturb nuclear morphology in a nucleus or nuclear region that is sufficiently soft, while stabilization of the nucleus via heterochromatin likely occurs through mechanisms other than chromatin microphase organization.
Collapse
|
11
|
Chen P, Mishra S, Prabha H, Sengupta S, Levy DL. Nuclear growth and import can be uncoupled. Mol Biol Cell 2024; 35:ar1. [PMID: 37903226 PMCID: PMC10881164 DOI: 10.1091/mbc.e23-04-0138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 09/29/2023] [Accepted: 10/18/2023] [Indexed: 11/01/2023] Open
Abstract
What drives nuclear growth? Studying nuclei assembled in Xenopus egg extract and focusing on importin α/β-mediated nuclear import, we show that, while import is required for nuclear growth, nuclear growth and import can be uncoupled when chromatin structure is manipulated. Nuclei treated with micrococcal nuclease to fragment DNA grew slowly despite exhibiting little to no change in import rates. Nuclei assembled around axolotl chromatin with 20-fold more DNA than Xenopus grew larger but imported more slowly. Treating nuclei with reagents known to alter histone methylation or acetylation caused nuclei to grow less while still importing to a similar extent or to grow larger without significantly increasing import. Nuclear growth but not import was increased in live sea urchin embryos treated with the DNA methylator N-nitrosodimethylamine. These data suggest that nuclear import is not the primary driving force for nuclear growth. Instead, we observed that nuclear blebs expanded preferentially at sites of high chromatin density and lamin addition, whereas small Benzonase-treated nuclei lacking DNA exhibited reduced lamin incorporation into the nuclear envelope. In summary, we report experimental conditions where nuclear import is not sufficient to drive nuclear growth, hypothesizing that this uncoupling is a result of altered chromatin structure.
Collapse
Affiliation(s)
- Pan Chen
- Department of Biochemistry and Molecular Biology and Zhejiang Key Laboratory of Pathophysiology, School of Basic Medical Sciences, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211, China
| | - Sampada Mishra
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071
| | - Haritha Prabha
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071
| | - Sourabh Sengupta
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071
| | - Daniel L. Levy
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071
| |
Collapse
|
12
|
Spegg V, Altmeyer M. Genome maintenance meets mechanobiology. Chromosoma 2024; 133:15-36. [PMID: 37581649 PMCID: PMC10904543 DOI: 10.1007/s00412-023-00807-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 06/20/2023] [Accepted: 07/26/2023] [Indexed: 08/16/2023]
Abstract
Genome stability is key for healthy cells in healthy organisms, and deregulated maintenance of genome integrity is a hallmark of aging and of age-associated diseases including cancer and neurodegeneration. To maintain a stable genome, genome surveillance and repair pathways are closely intertwined with cell cycle regulation and with DNA transactions that occur during transcription and DNA replication. Coordination of these processes across different time and length scales involves dynamic changes of chromatin topology, clustering of fragile genomic regions and repair factors into nuclear repair centers, mobilization of the nuclear cytoskeleton, and activation of cell cycle checkpoints. Here, we provide a general overview of cell cycle regulation and of the processes involved in genome duplication in human cells, followed by an introduction to replication stress and to the cellular responses elicited by perturbed DNA synthesis. We discuss fragile genomic regions that experience high levels of replication stress, with a particular focus on telomere fragility caused by replication stress at the ends of linear chromosomes. Using alternative lengthening of telomeres (ALT) in cancer cells and ALT-associated PML bodies (APBs) as examples of replication stress-associated clustered DNA damage, we discuss compartmentalization of DNA repair reactions and the role of protein properties implicated in phase separation. Finally, we highlight emerging connections between DNA repair and mechanobiology and discuss how biomolecular condensates, components of the nuclear cytoskeleton, and interfaces between membrane-bound organelles and membraneless macromolecular condensates may cooperate to coordinate genome maintenance in space and time.
Collapse
Affiliation(s)
- Vincent Spegg
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
| | - Matthias Altmeyer
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland.
| |
Collapse
|
13
|
Hara Y. Physical forces modulate interphase nuclear size. Curr Opin Cell Biol 2023; 85:102253. [PMID: 37801797 DOI: 10.1016/j.ceb.2023.102253] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 08/11/2023] [Accepted: 09/07/2023] [Indexed: 10/08/2023]
Abstract
The eukaryotic nucleus exhibits remarkable plasticity in size, adjusting dynamically to changes in cellular conditions such as during development and differentiation, and across species. Traditionally, the supply of structural constituents to the nuclear envelope has been proposed as the principal determinant of nuclear size. However, recent experimental and theoretical analyses have provided an alternative perspective, which emphasizes the crucial role of physical forces such as osmotic pressure and chromatin repulsion forces in regulating nuclear size. These forces can be modulated by the molecular profiles that traverse the nuclear envelope and assemble in the macromolecular complex. This leads to a new paradigm wherein multiple nuclear macromolecules that are not limited to only the structural constituents of the nuclear envelope, are involved in the control of nuclear size and related functions.
Collapse
Affiliation(s)
- Yuki Hara
- Evolutionary Cell Biology Laboratory, Faculty of Science, Yamaguchi University, Yoshida 1677-1, Yamaguchi City, 753-8512, Japan.
| |
Collapse
|
14
|
Buxboim A, Kronenberg-Tenga R, Salajkova S, Avidan N, Shahak H, Thurston A, Medalia O. Scaffold, mechanics and functions of nuclear lamins. FEBS Lett 2023; 597:2791-2805. [PMID: 37813648 DOI: 10.1002/1873-3468.14750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 09/05/2023] [Accepted: 09/26/2023] [Indexed: 10/11/2023]
Abstract
Nuclear lamins are type-V intermediate filaments that are involved in many nuclear processes. In mammals, A- and B-type lamins assemble into separate physical meshwork underneath the inner nuclear membrane, the nuclear lamina, with some residual fraction localized within the nucleoplasm. Lamins are the major part of the nucleoskeleton, providing mechanical strength and flexibility to protect the genome and allow nuclear deformability, while also contributing to gene regulation via interactions with chromatin. While lamins are the evolutionary ancestors of all intermediate filament family proteins, their ultimate filamentous assembly is markedly different from their cytoplasmic counterparts. Interestingly, hundreds of genetic mutations in the lamina proteins have been causally linked with a broad range of human pathologies, termed laminopathies. These include muscular, neurological and metabolic disorders, as well as premature aging diseases. Recent technological advances have contributed to resolving the filamentous structure of lamins and the corresponding lamina organization. In this review, we revisit the multiscale lamin organization and discuss its implications on nuclear mechanics and chromatin organization within lamina-associated domains.
Collapse
Affiliation(s)
- Amnon Buxboim
- The Rachel and Selim Benin School of Computer Science and Engineering and The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Israel
| | | | - Sarka Salajkova
- Department of Biochemistry, University of Zurich, Switzerland
| | - Nili Avidan
- The Rachel and Selim Benin School of Computer Science and Engineering and The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Israel
| | - Hen Shahak
- The Rachel and Selim Benin School of Computer Science and Engineering and The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Israel
| | - Alice Thurston
- Department of Biochemistry, University of Zurich, Switzerland
| | - Ohad Medalia
- Department of Biochemistry, University of Zurich, Switzerland
| |
Collapse
|
15
|
Berg IK, Currey ML, Gupta S, Berrada Y, Nguyen BV, Pho M, Patteson AE, Schwarz JM, Banigan EJ, Stephens AD. Transcription inhibition suppresses nuclear blebbing and rupture independently of nuclear rigidity. J Cell Sci 2023; 136:jcs261547. [PMID: 37756607 PMCID: PMC10660790 DOI: 10.1242/jcs.261547] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 09/18/2023] [Indexed: 09/29/2023] Open
Abstract
Chromatin plays an essential role in the nuclear mechanical response and determining nuclear shape, which maintain nuclear compartmentalization and function. However, major genomic functions, such as transcription activity, might also impact cell nuclear shape via blebbing and rupture through their effects on chromatin structure and dynamics. To test this idea, we inhibited transcription with several RNA polymerase II inhibitors in wild-type cells and perturbed cells that presented increased nuclear blebbing. Transcription inhibition suppressed nuclear blebbing for several cell types, nuclear perturbations and transcription inhibitors. Furthermore, transcription inhibition suppressed nuclear bleb formation, bleb stabilization and bleb-based nuclear ruptures. Interestingly, transcription inhibition did not alter the histone H3 lysine 9 (H3K9) modification state, nuclear rigidity, and actin compression and contraction, which typically control nuclear blebbing. Polymer simulations suggested that RNA polymerase II motor activity within chromatin could drive chromatin motions that deform the nuclear periphery. Our data provide evidence that transcription inhibition suppresses nuclear blebbing and rupture, in a manner separate and distinct from chromatin rigidity.
Collapse
Affiliation(s)
- Isabel K. Berg
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
- Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Marilena L. Currey
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Sarthak Gupta
- Department of Physics and BioInspired Syracuse, Syracuse University, Syracuse, NY 13244, USA
| | - Yasmin Berrada
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Bao V. Nguyen
- Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Mai Pho
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Alison E. Patteson
- Department of Physics and BioInspired Syracuse, Syracuse University, Syracuse, NY 13244, USA
| | - J. M. Schwarz
- Department of Physics and BioInspired Syracuse, Syracuse University, Syracuse, NY 13244, USA
- Indian Creek Farm, Ithaca, NY 14850, USA
| | - Edward J. Banigan
- Institute of Medical Engineering & Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Andrew D. Stephens
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
- Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA
| |
Collapse
|
16
|
Zhao B, Lv Y. A biomechanical view of epigenetic tumor regulation. J Biol Phys 2023; 49:283-307. [PMID: 37004697 PMCID: PMC10397176 DOI: 10.1007/s10867-023-09633-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 03/12/2023] [Indexed: 04/04/2023] Open
Abstract
The occurrence and development of tumors depend on a complex regulation by not only biochemical cues, but also biomechanical factors in tumor microenvironment. With the development of epigenetic theory, the regulation of biomechanical stimulation on tumor progress genetically is not enough to fully illustrate the mechanism of tumorigenesis. However, biomechanical regulation on tumor progress epigenetically is still in its infancy. Therefore, it is particularly important to integrate the existing relevant researches and develop the potential exploration. This work sorted out the existing researches on the regulation of tumor by biomechanical factors through epigenetic means, which contains summarizing the tumor epigenetic regulatory mode by biomechanical factors, exhibiting the influence of epigenetic regulation under mechanical stimulation, illustrating its existing applications, and prospecting the potential. This review aims to display the relevant knowledge through integrating the existing studies on epigenetic regulation in tumorigenesis under mechanical stimulation so as to provide theoretical basis and new ideas for potential follow-up research and clinical applications. Mechanical factors under physiological conditions stimulate the tumor progress through epigenetic ways, and new strategies are expected to be found with the development of epidrugs and related delivery systems.
Collapse
Affiliation(s)
- Boyuan Zhao
- Mechanobiology and Regenerative Medicine Laboratory, Bioengineering College, Chongqing University, Chongqing, 400044, People's Republic of China
| | - Yonggang Lv
- State Key Laboratory of New Textile Materials and Advanced Processing Technologies, Wuhan Textile University, No. 1 Sunshine Avenue, Jiangxia District, Wuhan, Hubei Province, 430200, People's Republic of China.
| |
Collapse
|
17
|
Ruben BS, Brahmachari S, Contessoto VG, Cheng RR, Oliveira Junior AB, Di Pierro M, Onuchic JN. Structural reorganization and relaxation dynamics of axially stressed chromosomes. Biophys J 2023; 122:1633-1645. [PMID: 36960531 PMCID: PMC10183323 DOI: 10.1016/j.bpj.2023.03.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 02/06/2023] [Accepted: 03/17/2023] [Indexed: 03/25/2023] Open
Abstract
Chromosomes endure mechanical stresses throughout the cell cycle; for example, resulting from the pulling of chromosomes by spindle fibers during mitosis or deformation of the nucleus during cell migration. The response to physical stress is closely related to chromosome structure and function. Micromechanical studies of mitotic chromosomes have revealed them to be remarkably extensible objects and informed early models of mitotic chromosome organization. We use a data-driven, coarse-grained polymer modeling approach to explore the relationship between the spatial organization of individual chromosomes and their emergent mechanical properties. In particular, we investigate the mechanical properties of our model chromosomes by axially stretching them. Simulated stretching led to a linear force-extension curve for small strain, with mitotic chromosomes behaving about 10-fold stiffer than interphase chromosomes. Studying their relaxation dynamics, we found that chromosomes are viscoelastic solids with a highly liquid-like, viscous behavior in interphase that becomes solid-like in mitosis. This emergent mechanical stiffness originates from lengthwise compaction, an effective potential capturing the activity of loop-extruding SMC complexes. Chromosomes denature under large strains via unraveling, which is characterized by opening of large-scale folding patterns. By quantifying the effect of mechanical perturbations on the chromosome's structural features, our model provides a nuanced understanding of in vivo mechanics of chromosomes.
Collapse
Affiliation(s)
- Benjamin S Ruben
- Center for Theoretical Biological Physics, Rice University, Houston, Texas; Biophysics PhD Program, Harvard University, Cambridge, Massachusetts.
| | | | | | - Ryan R Cheng
- Center for Theoretical Biological Physics, Rice University, Houston, Texas; Department of Chemistry, University of Kentucky, Lexington, Kentucky
| | | | - Michele Di Pierro
- Department of Physics, Northeastern University, Boston, Massachusetts; Center for Theoretical Biological Physics, Northeastern University, Boston, Massachusetts
| | - José N Onuchic
- Center for Theoretical Biological Physics, Rice University, Houston, Texas; Department of Physics and Astronomy, Department of Chemistry, Department of BioSciences, Rice University, Houston, Texas
| |
Collapse
|
18
|
Chen P, Mishra S, Levy DL. Nuclear growth and import can be uncoupled. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.19.537556. [PMID: 37131802 PMCID: PMC10153267 DOI: 10.1101/2023.04.19.537556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
What drives nuclear growth? Studying nuclei assembled in Xenopus egg extract and focusing on importin α/β-mediated nuclear import, we show that, while nuclear growth depends on nuclear import, nuclear growth and import can be uncoupled. Nuclei containing fragmented DNA grew slowly despite exhibiting normal import rates, suggesting nuclear import itself is insufficient to drive nuclear growth. Nuclei containing more DNA grew larger but imported more slowly. Altering chromatin modifications caused nuclei to grow less while still importing to the same extent or to grow larger without increasing nuclear import. Increasing heterochromatin in vivo in sea urchin embryos increased nuclear growth but not import. These data suggest that nuclear import is not the primary driving force for nuclear growth. Instead, live imaging showed that nuclear growth preferentially occurred at sites of high chromatin density and lamin addition, whereas small nuclei lacking DNA exhibited less lamin incorporation. Our hypothesized model is that lamin incorporation and nuclear growth are driven by chromatin mechanical properties, which depend on and can be tuned by nuclear import.
Collapse
Affiliation(s)
- Pan Chen
- Department of Biochemistry and Molecular Biology and Zhejiang Key Laboratory of Pathophysiology, School of Basic Medical Sciences, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211, China
| | - Sampada Mishra
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA
| | - Daniel L. Levy
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA
| |
Collapse
|
19
|
Nozaki T, Shinkai S, Ide S, Higashi K, Tamura S, Shimazoe MA, Nakagawa M, Suzuki Y, Okada Y, Sasai M, Onami S, Kurokawa K, Iida S, Maeshima K. Condensed but liquid-like domain organization of active chromatin regions in living human cells. SCIENCE ADVANCES 2023; 9:eadf1488. [PMID: 37018405 PMCID: PMC10075990 DOI: 10.1126/sciadv.adf1488] [Citation(s) in RCA: 34] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 03/07/2023] [Indexed: 05/31/2023]
Abstract
In eukaryotes, higher-order chromatin organization is spatiotemporally regulated as domains, for various cellular functions. However, their physical nature in living cells remains unclear (e.g., condensed domains or extended fiber loops; liquid-like or solid-like). Using novel approaches combining genomics, single-nucleosome imaging, and computational modeling, we investigated the physical organization and behavior of early DNA replicated regions in human cells, which correspond to Hi-C contact domains with active chromatin marks. Motion correlation analysis of two neighbor nucleosomes shows that nucleosomes form physically condensed domains with ~150-nm diameters, even in active chromatin regions. The mean-square displacement analysis between two neighbor nucleosomes demonstrates that nucleosomes behave like a liquid in the condensed domain on the ~150 nm/~0.5 s spatiotemporal scale, which facilitates chromatin accessibility. Beyond the micrometers/minutes scale, chromatin seems solid-like, which may contribute to maintaining genome integrity. Our study reveals the viscoelastic principle of the chromatin polymer; chromatin is locally dynamic and reactive but globally stable.
Collapse
Affiliation(s)
- Tadasu Nozaki
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
| | - Soya Shinkai
- Laboratory for Developmental Dynamics, Center for Biosystems Dynamics Research (BDR), RIKEN, Kobe, Hyogo 650-0047, Japan
| | - Satoru Ide
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
- Department of Genetics, School of Life Science, SOKENDAI (Graduate University for Advanced Studies), Mishima, Shizuoka 411-8540, Japan
| | - Koichi Higashi
- Department of Genetics, School of Life Science, SOKENDAI (Graduate University for Advanced Studies), Mishima, Shizuoka 411-8540, Japan
- Genome Evolution Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
| | - Sachiko Tamura
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
| | - Masa A. Shimazoe
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
- Department of Genetics, School of Life Science, SOKENDAI (Graduate University for Advanced Studies), Mishima, Shizuoka 411-8540, Japan
| | - Masaki Nakagawa
- Department of Computer Science and Engineering, Fukuoka Institute of Technology, Fukuoka, Fukuoka 811-0295, Japan
| | - Yutaka Suzuki
- Department of Computational Biology and Medical Sciences, University of Tokyo, 5-1-5 Kashiwanoha Kashiwa, Chiba 277-8562, Japan
| | - Yasushi Okada
- Laboratory for Cell Polarity Regulation, Center for Biosystems Dynamics Research (BDR), RIKEN, Suita, Osaka 565-0874, Japan
| | - Masaki Sasai
- Department of Complex Systems Science, Nagoya University, Nagoya 464-8601, Japan
- Fukui Institute for Fundamental Chemistry, Kyoto University, Kyoto 606-8103, Japan
| | - Shuichi Onami
- Laboratory for Developmental Dynamics, Center for Biosystems Dynamics Research (BDR), RIKEN, Kobe, Hyogo 650-0047, Japan
| | - Ken Kurokawa
- Department of Genetics, School of Life Science, SOKENDAI (Graduate University for Advanced Studies), Mishima, Shizuoka 411-8540, Japan
- Genome Evolution Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
| | - Shiori Iida
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
- Department of Genetics, School of Life Science, SOKENDAI (Graduate University for Advanced Studies), Mishima, Shizuoka 411-8540, Japan
| | - Kazuhiro Maeshima
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
- Department of Genetics, School of Life Science, SOKENDAI (Graduate University for Advanced Studies), Mishima, Shizuoka 411-8540, Japan
| |
Collapse
|
20
|
Liu S, Li Y, Hong Y, Wang M, Zhang H, Ma J, Qu K, Huang G, Lu TJ. Mechanotherapy in oncology: Targeting nuclear mechanics and mechanotransduction. Adv Drug Deliv Rev 2023; 194:114722. [PMID: 36738968 DOI: 10.1016/j.addr.2023.114722] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 12/23/2022] [Accepted: 01/28/2023] [Indexed: 02/05/2023]
Abstract
Mechanotherapy is proposed as a new option for cancer treatment. Increasing evidence suggests that characteristic differences are present in the nuclear mechanics and mechanotransduction of cancer cells compared with those of normal cells. Recent advances in understanding nuclear mechanics and mechanotransduction provide not only further insights into the process of malignant transformation but also useful references for developing new therapeutic approaches. Herein, we present an overview of the alterations of nuclear mechanics and mechanotransduction in cancer cells and highlight their implications in cancer mechanotherapy.
Collapse
Affiliation(s)
- Shaobao Liu
- State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, PR China; MIIT Key Laboratory of Multifunctional Lightweight Materials and Structures, Nanjing University of Aeronautics, Nanjing 210016, PR China
| | - Yuan Li
- MOE Key Laboratory of Biomedical Information Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China; Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an 710049, PR China
| | - Yuan Hong
- MOE Key Laboratory of Biomedical Information Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China; Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an 710049, PR China; National Science Foundation Science and Technology Center for Engineering Mechanobiology, Washington University, St. Louis, MO 63130, USA
| | - Ming Wang
- MOE Key Laboratory of Biomedical Information Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China; Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an 710049, PR China
| | - Hao Zhang
- State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, PR China; MIIT Key Laboratory of Multifunctional Lightweight Materials and Structures, Nanjing University of Aeronautics, Nanjing 210016, PR China
| | - Jinlu Ma
- Department of Radiation Oncology, the First Affiliated Hospital, Xian Jiaotong University, Xi'an 710061, PR China
| | - Kai Qu
- Department of Hepatobiliary Surgery, the First Affiliated Hospital, Xian Jiaotong University, Xi'an 710061, PR China
| | - Guoyou Huang
- Department of Engineering Mechanics, School of Civil Engineering, Wuhan University, Wuhan 430072, PR China.
| | - Tian Jian Lu
- State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, PR China; MIIT Key Laboratory of Multifunctional Lightweight Materials and Structures, Nanjing University of Aeronautics, Nanjing 210016, PR China.
| |
Collapse
|
21
|
Heijo H, Merten CA, Hara Y. Differential contribution of nuclear size scaling mechanisms between Xenopus species. Dev Growth Differ 2022; 64:501-507. [PMID: 36308491 DOI: 10.1111/dgd.12819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 08/24/2022] [Accepted: 10/05/2022] [Indexed: 12/31/2022]
Abstract
Size of the nucleus, a membrane-bound organelle for DNA replication and transcription in eukaryotic cells, varies to adapt nuclear functions to the surrounding environment. Nuclear size strongly correlates with cytoplasmic size and genomic content. Previous studies using Xenopus laevis have unraveled two modes, cytoplasmic and chromatin-based mechanisms, for controlling nuclear size. However, owing to limited comparative analyses of the mechanisms among eukaryotic species, the contribution of each mechanism in controlling nuclear size has not been comprehensively elucidated. Here, we compared the relative contribution utilizing a cell-free reconstruction system from the cytoplasmic extract of unfertilized eggs of Xenopus tropicalis to that of the sister species X. laevis. In this system, interphase nuclei were reconstructed in vitro from sperm chromatin and increased in size throughout the incubation period. Using extracts from X. tropicalis, growth rate of the reconstructed nuclei was decreased by obstructing the effective cytoplasmic space, decreasing DNA quantity, or inhibiting molecules involved in various cytoplasmic mechanisms. Although these features are qualitatively identical to that shown by the extract of X. laevis, the sensitivities of experimental manipulation for each cellular parameter were different between the extracts from two Xenopus species. These quantitative differences implied that the contribution of each mode to expansion of the nuclear envelope is coordinated in a species-specific manner, which sets the species-specific nuclear size for in vivo physiological function.
Collapse
Affiliation(s)
- Hiroko Heijo
- Evolutionary Cell Biology Laboratory, Faculty of Science, Yamaguchi University, Yamaguchi City, Japan
| | - Christoph A Merten
- Laboratory of Biomedical Microfluidics (LBMM), Department of Bioengineering, School of Engineering, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland
| | - Yuki Hara
- Evolutionary Cell Biology Laboratory, Faculty of Science, Yamaguchi University, Yamaguchi City, Japan
| |
Collapse
|
22
|
Liu L, Simon M, Muggiolu G, Vilotte F, Antoine M, Caron J, Kantor G, Barberet P, Seznec H, Audoin B. Changes in intra-nuclear mechanics in response to DNA damaging agents revealed by time-domain Brillouin micro-spectroscopy. PHOTOACOUSTICS 2022; 27:100385. [PMID: 36068801 PMCID: PMC9441258 DOI: 10.1016/j.pacs.2022.100385] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 07/05/2022] [Accepted: 07/08/2022] [Indexed: 05/25/2023]
Abstract
How DNA damage and repair processes affect the biomechanical properties of the nucleus interior remains unknown. Here, an opto-acoustic microscope based on time-domain Brillouin spectroscopy (TDBS) was used to investigate the induced regulation of intra-nuclear mechanics. With this ultrafast pump-probe technique, coherent acoustic phonons were tracked along their propagation in the intra-nucleus nanostructure and the complex stiffness moduli and thicknesses were measured with an optical resolution. Osteosarcoma cells were exposed to methyl methanesulfonate (MMS) and the presence of DNA damage was tested using immunodetection targeted against damage signaling proteins. TDBS revealed that the intra-nuclear storage modulus decreased significantly upon exposure to MMS, as a result of the chromatin decondensation and reorganization that favors molecular diffusion within the organelle. When the damaging agent was removed and cells incubated for 2 h in the buffer solution before fixation the intra-nuclear reorganization led to an inverse evolution of the storage modulus, the nucleus stiffened. The same tendency was measured when DNA double-strand breaks were caused by cell exposure to ionizing radiation. TDBS microscopy also revealed changes in acoustic dissipation, another mechanical probe of the intra-nucleus organization at the nano-scale, and changes in nucleus thickness during exposure to MMS and after recovery.
Collapse
Affiliation(s)
- Liwang Liu
- Univ. Bordeaux, CNRS, I2M, UMR 5295, F-33400 Talence, France
| | - Marina Simon
- Univ. Bordeaux, CNRS, CENBG, UMR 5797, F-33170 Gradignan, France
| | | | - Florent Vilotte
- Univ. Bordeaux, CNRS, CENBG, UMR 5797, F-33170 Gradignan, France
- Department of Radiotherapy, Institut Bergonié, Comprehensive Regional Cancer Centre of Bordeaux and Southwest and University of Bordeaux, France
| | - Mikael Antoine
- Department of Radiotherapy, Institut Bergonié, Comprehensive Regional Cancer Centre of Bordeaux and Southwest and University of Bordeaux, France
| | - Jerôme Caron
- Department of Radiotherapy, Institut Bergonié, Comprehensive Regional Cancer Centre of Bordeaux and Southwest and University of Bordeaux, France
| | - Guy Kantor
- Department of Radiotherapy, Institut Bergonié, Comprehensive Regional Cancer Centre of Bordeaux and Southwest and University of Bordeaux, France
| | | | - Hervé Seznec
- Univ. Bordeaux, CNRS, CENBG, UMR 5797, F-33170 Gradignan, France
| | - Bertrand Audoin
- Univ. Bordeaux, CNRS, I2M, UMR 5295, F-33400 Talence, France
| |
Collapse
|
23
|
Currey ML, Kandula V, Biggs R, Marko JF, Stephens AD. A Versatile Micromanipulation Apparatus for Biophysical Assays of the Cell Nucleus. Cell Mol Bioeng 2022; 15:303-312. [PMID: 36119136 PMCID: PMC9474788 DOI: 10.1007/s12195-022-00734-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 08/08/2022] [Indexed: 12/02/2022] Open
Abstract
Intro Force measurements of the nucleus, the strongest organelle, have propelled the field of mechanobiology to understand the basic mechanical components of the nucleus and how these components properly support nuclear morphology and function. Micromanipulation force measurement provides separation of the relative roles of nuclear mechanical components chromatin and lamin A. Methods To provide access to this technique, we have developed a universal micromanipulation apparatus for inverted microscopes. We outline how to engineer and utilize this apparatus through dual micromanipulators, fashion and calibrate micropipettes, and flow systems to isolate a nucleus and provide force vs. extensions measurements. This force measurement approach provides the unique ability to measure the separate contributions of chromatin at short extensions and lamin A strain stiffening at long extensions. We then investigated the apparatus' controllable and programmable micromanipulators through compression, isolation, and extension in conjunction with fluorescence to develop new assays for nuclear mechanobiology. Results Using this methodology, we provide the first rebuilding of the micromanipulation setup outside of its lab of origin and recapitulate many key findings including spring constant of the nucleus and strain stiffening across many cell types. Furthermore, we have developed new micromanipulation-based techniques to compress nuclei inducing nuclear deformation and/or rupture, track nuclear shape post-isolation, and fluorescence imaging during micromanipulation force measurements. Conclusion We provide the workflow to build and use a micromanipulation apparatus with any inverted microscope to perform nucleus isolation, force measurements, and various other biophysical techniques. Supplementary Information The online version contains supplementary material available at 10.1007/s12195-022-00734-y.
Collapse
Affiliation(s)
| | - Viswajit Kandula
- Department of Molecular Biosciences and Department of Physics & Astronomy, Northwestern University, Evanston, USA
- Feinberg School of Medicine, Northwestern University, Chicago, USA
| | - Ronald Biggs
- Department of Molecular Biosciences and Department of Physics & Astronomy, Northwestern University, Evanston, USA
| | - John F. Marko
- Department of Molecular Biosciences and Department of Physics & Astronomy, Northwestern University, Evanston, USA
| | - Andrew D. Stephens
- Biology Department, University of Massachusetts Amherst, Amherst, USA
- Molecular and Cellular Biosciences, University of Massachusetts Amherst, Amherst, USA
| |
Collapse
|
24
|
Keizer VIP, Grosse-Holz S, Woringer M, Zambon L, Aizel K, Bongaerts M, Delille F, Kolar-Znika L, Scolari VF, Hoffmann S, Banigan EJ, Mirny LA, Dahan M, Fachinetti D, Coulon A. Live-cell micromanipulation of a genomic locus reveals interphase chromatin mechanics. Science 2022; 377:489-495. [PMID: 35901134 DOI: 10.1126/science.abi9810] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Our understanding of the physical principles organizing the genome in the nucleus is limited by the lack of tools to directly exert and measure forces on interphase chromosomes in vivo and probe their material nature. Here, we introduce an approach to actively manipulate a genomic locus using controlled magnetic forces inside the nucleus of a living human cell. We observed viscoelastic displacements over micrometers within minutes in response to near-piconewton forces, which are consistent with a Rouse polymer model. Our results highlight the fluidity of chromatin, with a moderate contribution of the surrounding material, revealing minor roles for cross-links and topological effects and challenging the view that interphase chromatin is a gel-like material. Our technology opens avenues for future research in areas from chromosome mechanics to genome functions.
Collapse
Affiliation(s)
- Veer I P Keizer
- Institut Curie, PSL Research University, Sorbonne Université, CNRS UMR3664, Laboratoire Dynamique du Noyau, 75005 Paris, France.,Institut Curie, PSL Research University, Sorbonne Université, CNRS UMR168, Laboratoire Physico Chimie Curie, 75005 Paris, France.,Institut Curie, PSL Research University, CNRS UMR144, Laboratoire Biologie Cellulaire et Cancer, 75005 Paris, France
| | - Simon Grosse-Holz
- Institut Curie, PSL Research University, Sorbonne Université, CNRS UMR3664, Laboratoire Dynamique du Noyau, 75005 Paris, France.,Institut Curie, PSL Research University, Sorbonne Université, CNRS UMR168, Laboratoire Physico Chimie Curie, 75005 Paris, France.,Department of Physics and Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Maxime Woringer
- Institut Curie, PSL Research University, Sorbonne Université, CNRS UMR3664, Laboratoire Dynamique du Noyau, 75005 Paris, France.,Institut Curie, PSL Research University, Sorbonne Université, CNRS UMR168, Laboratoire Physico Chimie Curie, 75005 Paris, France
| | - Laura Zambon
- Institut Curie, PSL Research University, Sorbonne Université, CNRS UMR3664, Laboratoire Dynamique du Noyau, 75005 Paris, France.,Institut Curie, PSL Research University, Sorbonne Université, CNRS UMR168, Laboratoire Physico Chimie Curie, 75005 Paris, France.,Institut Curie, PSL Research University, CNRS UMR144, Laboratoire Biologie Cellulaire et Cancer, 75005 Paris, France
| | - Koceila Aizel
- Institut Curie, PSL Research University, Sorbonne Université, CNRS UMR168, Laboratoire Physico Chimie Curie, 75005 Paris, France
| | - Maud Bongaerts
- Institut Curie, PSL Research University, Sorbonne Université, CNRS UMR168, Laboratoire Physico Chimie Curie, 75005 Paris, France
| | - Fanny Delille
- ESPCI Paris, PSL Research University, Sorbonne Université, CNRS UMR8213, Laboratoire de Physique et d'Étude des Matériaux, 75005 Paris, France
| | - Lorena Kolar-Znika
- Institut Curie, PSL Research University, Sorbonne Université, CNRS UMR3664, Laboratoire Dynamique du Noyau, 75005 Paris, France.,Institut Curie, PSL Research University, Sorbonne Université, CNRS UMR168, Laboratoire Physico Chimie Curie, 75005 Paris, France
| | - Vittore F Scolari
- Institut Curie, PSL Research University, Sorbonne Université, CNRS UMR3664, Laboratoire Dynamique du Noyau, 75005 Paris, France.,Institut Curie, PSL Research University, Sorbonne Université, CNRS UMR168, Laboratoire Physico Chimie Curie, 75005 Paris, France
| | - Sebastian Hoffmann
- Institut Curie, PSL Research University, CNRS UMR144, Laboratoire Biologie Cellulaire et Cancer, 75005 Paris, France
| | - Edward J Banigan
- Department of Physics and Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Leonid A Mirny
- Institut Curie, PSL Research University, Sorbonne Université, CNRS UMR3664, Laboratoire Dynamique du Noyau, 75005 Paris, France.,Department of Physics and Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Maxime Dahan
- Institut Curie, PSL Research University, Sorbonne Université, CNRS UMR168, Laboratoire Physico Chimie Curie, 75005 Paris, France
| | - Daniele Fachinetti
- Institut Curie, PSL Research University, CNRS UMR144, Laboratoire Biologie Cellulaire et Cancer, 75005 Paris, France
| | - Antoine Coulon
- Institut Curie, PSL Research University, Sorbonne Université, CNRS UMR3664, Laboratoire Dynamique du Noyau, 75005 Paris, France.,Institut Curie, PSL Research University, Sorbonne Université, CNRS UMR168, Laboratoire Physico Chimie Curie, 75005 Paris, France
| |
Collapse
|
25
|
Niide T, Asari S, Kawabata K, Hara Y. Specificity of Nuclear Size Scaling in Frog Erythrocytes. Front Cell Dev Biol 2022; 10:857862. [PMID: 35663388 PMCID: PMC9159806 DOI: 10.3389/fcell.2022.857862] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 04/21/2022] [Indexed: 11/29/2022] Open
Abstract
In eukaryotes, the cell has the ability to modulate the size of the nucleus depending on the surrounding environment, to enable nuclear functions such as DNA replication and transcription. From previous analyses of nuclear size scaling in various cell types and species, it has been found that eukaryotic cells have a conserved scaling rule, in which the nuclear size correlates with both cell size and genomic content. However, there are few studies that have focused on a certain cell type and systematically analyzed the size scaling properties in individual species (intra-species) and among species (inter-species), and thus, the difference in the scaling rules among cell types and species is not well understood. In the present study, we analyzed the size scaling relationship among three parameters, nuclear size, cell size, and genomic content, in our measured datasets of terminally differentiated erythrocytes of five Anura frogs and collected datasets of different species classes from published papers. In the datasets of isolated erythrocytes from individual frogs, we found a very weak correlation between the measured nuclear and cell cross-sectional areas. Within the erythrocytes of individual species, the correlation of the nuclear area with the cell area showed a very low hypoallometric relationship, in which the relative nuclear size decreased when the cell size increased. These scaling trends in intra-species erythrocytes are not comparable to the known general correlation in other cell types. When comparing parameters across species, the nuclear areas correlated with both cell areas and genomic contents among the five frogs and the collected datasets in each species class. However, the contribution of genomic content to nuclear size determination was smaller than that of the cell area in all species classes. In particular, the estimated degree of the contribution of genomic content was greater in the amphibian class than in other classes. Together with our imaging analysis of structural components in nuclear membranes, we hypothesized that the observed specific features in nuclear size scaling are achieved by the weak interaction of the chromatin with the nuclear membrane seen in frog erythrocytes.
Collapse
Affiliation(s)
| | | | | | - Yuki Hara
- Evolutionary Cell Biology Laboratory, Faculty of Science, Yamaguchi University, Yamaguchi, Japan
| |
Collapse
|
26
|
Vahabikashi A, Adam SA, Medalia O, Goldman RD. Nuclear lamins: Structure and function in mechanobiology. APL Bioeng 2022; 6:011503. [PMID: 35146235 PMCID: PMC8810204 DOI: 10.1063/5.0082656] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 01/11/2022] [Indexed: 12/11/2022] Open
Abstract
Nuclear lamins are type V intermediate filament proteins that polymerize into complex filamentous meshworks at the nuclear periphery and in less structured forms throughout the nucleoplasm. Lamins interact with a wide range of nuclear proteins and are involved in numerous nuclear and cellular functions. Within the nucleus, they play roles in chromatin organization and gene regulation, nuclear shape, size, and mechanics, and the organization and anchorage of nuclear pore complexes. At the whole cell level, they are involved in the organization of the cytoskeleton, cell motility, and mechanotransduction. The expression of different lamin isoforms has been associated with developmental progression, differentiation, and tissue-specific functions. Mutations in lamins and their binding proteins result in over 15 distinct human diseases, referred to as laminopathies. The laminopathies include muscular (e.g., Emery-Dreifuss muscular dystrophy and dilated cardiomyopathy), neurological (e.g., microcephaly), and metabolic (e.g., familial partial lipodystrophy) disorders as well as premature aging diseases (e.g., Hutchinson-Gilford Progeria and Werner syndromes). How lamins contribute to the etiology of laminopathies is still unknown. In this review article, we summarize major recent findings on the structure, organization, and multiple functions of lamins in nuclear and more global cellular processes.
Collapse
Affiliation(s)
- Amir Vahabikashi
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
| | - Stephen A. Adam
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
| | - Ohad Medalia
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Robert D. Goldman
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
| |
Collapse
|
27
|
Mierke CT. Viscoelasticity, Like Forces, Plays a Role in Mechanotransduction. Front Cell Dev Biol 2022; 10:789841. [PMID: 35223831 PMCID: PMC8864183 DOI: 10.3389/fcell.2022.789841] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 01/11/2022] [Indexed: 12/13/2022] Open
Abstract
Viscoelasticity and its alteration in time and space has turned out to act as a key element in fundamental biological processes in living systems, such as morphogenesis and motility. Based on experimental and theoretical findings it can be proposed that viscoelasticity of cells, spheroids and tissues seems to be a collective characteristic that demands macromolecular, intracellular component and intercellular interactions. A major challenge is to couple the alterations in the macroscopic structural or material characteristics of cells, spheroids and tissues, such as cell and tissue phase transitions, to the microscopic interferences of their elements. Therefore, the biophysical technologies need to be improved, advanced and connected to classical biological assays. In this review, the viscoelastic nature of cytoskeletal, extracellular and cellular networks is presented and discussed. Viscoelasticity is conceptualized as a major contributor to cell migration and invasion and it is discussed whether it can serve as a biomarker for the cells' migratory capacity in several biological contexts. It can be hypothesized that the statistical mechanics of intra- and extracellular networks may be applied in the future as a powerful tool to explore quantitatively the biomechanical foundation of viscoelasticity over a broad range of time and length scales. Finally, the importance of the cellular viscoelasticity is illustrated in identifying and characterizing multiple disorders, such as cancer, tissue injuries, acute or chronic inflammations or fibrotic diseases.
Collapse
Affiliation(s)
- Claudia Tanja Mierke
- Faculty of Physics and Earth Science, Peter Debye Institute of Soft Matter Physics, Biological Physics Division, University of Leipzig, Leipzig, Germany
| |
Collapse
|
28
|
Abstract
Lamins interact with a host of nuclear membrane proteins, transcription factors, chromatin regulators, signaling molecules, splicing factors, and even chromatin itself to form a nuclear subcompartment, the nuclear lamina, that is involved in a variety of cellular processes such as the governance of nuclear integrity, nuclear positioning, mitosis, DNA repair, DNA replication, splicing, signaling, mechanotransduction and -sensation, transcriptional regulation, and genome organization. Lamins are the primary scaffold for this nuclear subcompartment, but interactions with lamin-associated peptides in the inner nuclear membrane are self-reinforcing and mutually required. Lamins also interact, directly and indirectly, with peripheral heterochromatin domains called lamina-associated domains (LADs) and help to regulate dynamic 3D genome organization and expression of developmentally regulated genes.
Collapse
Affiliation(s)
- Xianrong Wong
- Laboratory of Developmental and Regenerative Biology, Skin Research Institute of Singapore, Agency for Science, Technology and Research (A∗STAR), Singapore 138648
| | - Ashley J Melendez-Perez
- Department of Biological Chemistry and Center for Epigenetics, Johns Hopkins University of Medicine, Baltimore, Maryland 21205, USA
| | - Karen L Reddy
- Department of Biological Chemistry and Center for Epigenetics, Johns Hopkins University of Medicine, Baltimore, Maryland 21205, USA
- Sidney Kimmel Cancer Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, USA
| |
Collapse
|
29
|
Chi YH, Wang WP, Hung MC, Liou GG, Wang JY, Chao PHG. Deformation of the nucleus by TGFβ1 via the remodeling of nuclear envelope and histone isoforms. Epigenetics Chromatin 2022; 15:1. [PMID: 34983624 PMCID: PMC8725468 DOI: 10.1186/s13072-021-00434-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 12/24/2021] [Indexed: 11/18/2022] Open
Abstract
The cause of nuclear shape abnormalities which are often seen in pre-neoplastic and malignant tissues is not clear. In this study we report that deformation of the nucleus can be induced by TGFβ1 stimulation in several cell lines including Huh7. In our results, the upregulated histone H3.3 expression downstream of SMAD signaling contributed to TGFβ1-induced nuclear deformation, a process of which requires incorporation of the nuclear envelope (NE) proteins lamin B1 and SUN1. During this process, the NE constitutively ruptured and reformed. Contrast to lamin B1 which was relatively stationary around the nucleus, the upregulated lamin A was highly mobile, clustering at the nuclear periphery and reintegrating into the nucleoplasm. The chromatin regions that lost NE coverage formed a supra-nucleosomal structure characterized by elevated histone H3K27me3 and histone H1, the formation of which depended on the presence of lamin A. These results provide evidence that shape of the nucleus can be modulated through TGFβ1-induced compositional changes in the chromatin and nuclear lamina.
Collapse
Affiliation(s)
- Ya-Hui Chi
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, 35 Keyan Road, Zhunan, Miaoli County, 35053, Taiwan. .,Graduate Institute of Biomedical Sciences, China Medical University, Taichung, 40402, Taiwan.
| | - Wan-Ping Wang
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, 35 Keyan Road, Zhunan, Miaoli County, 35053, Taiwan
| | - Ming-Chun Hung
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, 35 Keyan Road, Zhunan, Miaoli County, 35053, Taiwan
| | - Gunn-Guang Liou
- National Taiwan University College of Medicine, Taipei, 10051, Taiwan
| | - Jing-Ya Wang
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, 35 Keyan Road, Zhunan, Miaoli County, 35053, Taiwan
| | - Pen-Hsiu Grace Chao
- Department of Biomedical Engineering, School of Medicine and School of Engineering, National Taiwan University, Taipei, 10617, Taiwan
| |
Collapse
|
30
|
Hobson CM, Falvo MR, Superfine R. A survey of physical methods for studying nuclear mechanics and mechanobiology. APL Bioeng 2021; 5:041508. [PMID: 34849443 PMCID: PMC8604565 DOI: 10.1063/5.0068126] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 10/20/2021] [Indexed: 12/23/2022] Open
Abstract
It is increasingly appreciated that the cell nucleus is not only a home for DNA but also a complex material that resists physical deformations and dynamically responds to external mechanical cues. The molecules that confer mechanical properties to nuclei certainly contribute to laminopathies and possibly contribute to cellular mechanotransduction and physical processes in cancer such as metastasis. Studying nuclear mechanics and the downstream biochemical consequences or their modulation requires a suite of complex assays for applying, measuring, and visualizing mechanical forces across diverse length, time, and force scales. Here, we review the current methods in nuclear mechanics and mechanobiology, placing specific emphasis on each of their unique advantages and limitations. Furthermore, we explore important considerations in selecting a new methodology as are demonstrated by recent examples from the literature. We conclude by providing an outlook on the development of new methods and the judicious use of the current techniques for continued exploration into the role of nuclear mechanobiology.
Collapse
Affiliation(s)
| | - Michael R. Falvo
- Department of Physics and Astronomy, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Richard Superfine
- Department of Applied Physical Science, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| |
Collapse
|
31
|
Matsushita K, Nakahara C, Kimura S, Sakamoto N, Ii S, Miyoshi H. Intranuclear mesoscale viscoelastic changes during osteoblastic differentiation of human mesenchymal stem cells. FASEB J 2021; 35:e22071. [PMID: 34820910 DOI: 10.1096/fj.202100536rr] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 11/07/2021] [Accepted: 11/12/2021] [Indexed: 11/11/2022]
Abstract
Cell nuclei behave as viscoelastic materials. Dynamic regulation of the viscoelastic properties of nuclei in living cells is crucial for diverse biological and biophysical processes, specifically for intranuclear mesoscale viscoelasticity, through modulation of the efficiency of force propagation to the nucleoplasm and gene expression patterns. However, how the intranuclear mesoscale viscoelasticity of stem cells changes with differentiation is unclear and so is its biological significance. Here, we quantified the changes in intranuclear mesoscale viscoelasticity during osteoblastic differentiation of human mesenchymal stem cells. This analysis revealed that the intranuclear region is a viscoelastic solid, probably with a higher efficiency of force transmission that results in high sensitivity to mechanical signals in the early stages of osteoblastic differentiation. The intranuclear region was noted to alter to a viscoelastic liquid with a lower efficiency, which is responsible for the robustness of gene expression toward terminal differentiation. Additionally, evaluation of changes in the mesoscale viscoelasticity due to chromatin decondensation and correlation between the mesoscale viscoelasticity and local DNA density suggested that size of gap and flexibility of chromatin meshwork structures, which are modulated depending on chromatin condensation state, determine mesoscale viscoelasticity, with various rates of contribution in different differentiation stages. Given that chromatin within the nucleus condenses into heterochromatin as stem cells adopt a specific lineage by restricting transcription, viscoelasticity is perhaps a key factor in cooperative regulation of the nuclear mechanosensitivity and gene expression pattern for stem cell differentiation.
Collapse
Affiliation(s)
- Kojiro Matsushita
- Department of Mechanical Systems Engineering, Graduate School of Systems Design, Tokyo Metropolitan University, Hachioji, Japan
| | - Chiharu Nakahara
- Department of Mechanical Systems Engineering, Graduate School of Systems Design, Tokyo Metropolitan University, Hachioji, Japan
| | - Shun Kimura
- Department of Mechanical Systems Engineering, Graduate School of Systems Design, Tokyo Metropolitan University, Hachioji, Japan
| | - Naoya Sakamoto
- Department of Mechanical Systems Engineering, Graduate School of Systems Design, Tokyo Metropolitan University, Hachioji, Japan
| | - Satoshi Ii
- Department of Mechanical Systems Engineering, Graduate School of Systems Design, Tokyo Metropolitan University, Hachioji, Japan
| | - Hiromi Miyoshi
- Department of Mechanical Systems Engineering, Graduate School of Systems Design, Tokyo Metropolitan University, Hachioji, Japan
| |
Collapse
|
32
|
Hansen JC, Maeshima K, Hendzel MJ. The solid and liquid states of chromatin. Epigenetics Chromatin 2021; 14:50. [PMID: 34717733 PMCID: PMC8557566 DOI: 10.1186/s13072-021-00424-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 10/22/2021] [Indexed: 12/14/2022] Open
Abstract
The review begins with a concise description of the principles of phase separation. This is followed by a comprehensive section on phase separation of chromatin, in which we recount the 60 years history of chromatin aggregation studies, discuss the evidence that chromatin aggregation intrinsically is a physiologically relevant liquid-solid phase separation (LSPS) process driven by chromatin self-interaction, and highlight the recent findings that under specific solution conditions chromatin can undergo liquid-liquid phase separation (LLPS) rather than LSPS. In the next section of the review, we discuss how certain chromatin-associated proteins undergo LLPS in vitro and in vivo. Some chromatin-binding proteins undergo LLPS in purified form in near-physiological ionic strength buffers while others will do so only in the presence of DNA, nucleosomes, or chromatin. The final section of the review evaluates the solid and liquid states of chromatin in the nucleus. While chromatin behaves as an immobile solid on the mesoscale, nucleosomes are mobile on the nanoscale. We discuss how this dual nature of chromatin, which fits well the concept of viscoelasticity, contributes to genome structure, emphasizing the dominant role of chromatin self-interaction.
Collapse
Affiliation(s)
- Jeffrey C Hansen
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, 80523, USA.
| | - Kazuhiro Maeshima
- Genome Dynamics Laboratory, National Institute of Genetics, and Department of Genetics, Sokendai (Graduate University for Advanced Studies), Mishima, Shizuoka, 411-8540, Japan.
| | - Michael J Hendzel
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.
- Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.
| |
Collapse
|
33
|
The Role of Emerin in Cancer Progression and Metastasis. Int J Mol Sci 2021; 22:ijms222011289. [PMID: 34681951 PMCID: PMC8537873 DOI: 10.3390/ijms222011289] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 10/14/2021] [Accepted: 10/15/2021] [Indexed: 12/27/2022] Open
Abstract
It is commonly recognized in the field that cancer cells exhibit changes in the size and shape of their nuclei. These features often serve as important biomarkers in the diagnosis and prognosis of cancer patients. Nuclear size can significantly impact cell migration due to its incredibly large size. Nuclear structural changes are predicted to regulate cancer cell migration. Nuclear abnormalities are common across a vast spectrum of cancer types, regardless of tissue source, mutational spectrum, and signaling dependencies. The pervasiveness of nuclear alterations suggests that changes in nuclear structure may be crucially linked to the transformation process. The factors driving these nuclear abnormalities, and the functional consequences, are not completely understood. Nuclear envelope proteins play an important role in regulating nuclear size and structure in cancer. Altered expression of nuclear lamina proteins, including emerin, is found in many cancers and this expression is correlated with better clinical outcomes. A model is emerging whereby emerin, as well as other nuclear lamina proteins, binding to the nucleoskeleton regulates the nuclear structure to impact metastasis. In this model, emerin and lamins play a central role in metastatic transformation, since decreased emerin expression during transformation causes the nuclear structural defects required for increased cell migration, intravasation, and extravasation. Herein, we discuss the cellular functions of nuclear lamina proteins, with a particular focus on emerin, and how these functions impact cancer progression and metastasis.
Collapse
|
34
|
Abstract
The cell nucleus is best known as the container of the genome. Its envelope provides a barrier for passive macromolecule diffusion, which enhances the control of gene expression. As its largest and stiffest organelle, the nucleus also defines the minimal space requirements of a cell. Internal or external pressures that deform a cell to its physical limits cause a corresponding nuclear deformation. Evidence is consolidating that the nucleus, in addition to its genetic functions, serves as a physical sensing device for critical cell body deformation. Nuclear mechanotransduction allows cells to adapt their acute behaviors, mechanical stability, paracrine signaling, and fate to their physical surroundings. This review summarizes the basic chemical and mechanical properties of nuclear components, and how these properties are thought to be utilized for mechanosensing.
Collapse
Affiliation(s)
- Philipp Niethammer
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA;
| |
Collapse
|
35
|
Mori M, Yao T, Mishina T, Endoh H, Tanaka M, Yonezawa N, Shimamoto Y, Yonemura S, Yamagata K, Kitajima TS, Ikawa M. RanGTP and the actin cytoskeleton keep paternal and maternal chromosomes apart during fertilization. J Cell Biol 2021; 220:e202012001. [PMID: 34424312 PMCID: PMC8404465 DOI: 10.1083/jcb.202012001] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 06/18/2021] [Accepted: 08/06/2021] [Indexed: 11/22/2022] Open
Abstract
Zygotes require two accurate sets of parental chromosomes, one each from the mother and the father, to undergo normal embryogenesis. However, upon egg-sperm fusion in vertebrates, the zygote has three sets of chromosomes, one from the sperm and two from the egg. The zygote therefore eliminates one set of maternal chromosomes (but not the paternal chromosomes) into the polar body through meiosis, but how the paternal chromosomes are protected from maternal meiosis has been unclear. Here we report that RanGTP and F-actin dynamics prevent egg-sperm fusion in proximity to maternal chromosomes. RanGTP prevents the localization of Juno and CD9, egg membrane proteins that mediate sperm fusion, at the cell surface in proximity to maternal chromosomes. Following egg-sperm fusion, F-actin keeps paternal chromosomes away from maternal chromosomes. Disruption of these mechanisms causes the elimination of paternal chromosomes during maternal meiosis. This study reveals a novel critical mechanism that prevents aneuploidy in zygotes.
Collapse
Affiliation(s)
- Masashi Mori
- Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
- Laboratory for Chromosome Segregation, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
| | - Tatsuma Yao
- Research and Development Center, Fuso Pharmaceutical Industries, Ltd., Osaka, Japan
- Graduate School of Biology-Oriented Science and Technology, Kindai University, Wakayama, Japan
| | - Tappei Mishina
- Laboratory for Chromosome Segregation, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
| | - Hiromi Endoh
- Laboratory for Ultrastructural Research, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
| | - Masahito Tanaka
- Physics and Cell Biology Laboratory, National Institute of Genetics & Department of Genetics, SOKENDAI University, Kanagawa, Japan
| | - Nao Yonezawa
- Graduate School of Biology-Oriented Science and Technology, Kindai University, Wakayama, Japan
| | - Yuta Shimamoto
- Physics and Cell Biology Laboratory, National Institute of Genetics & Department of Genetics, SOKENDAI University, Kanagawa, Japan
| | - Shigenobu Yonemura
- Laboratory for Ultrastructural Research, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
- Department of Cell Biology, Tokushima University Graduate School of Medical Science, Tokushima, Japan
| | - Kazuo Yamagata
- Graduate School of Biology-Oriented Science and Technology, Kindai University, Wakayama, Japan
| | - Tomoya S. Kitajima
- Laboratory for Chromosome Segregation, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
| | - Masahito Ikawa
- Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| |
Collapse
|
36
|
Itoh Y, Woods EJ, Minami K, Maeshima K, Collepardo-Guevara R. Liquid-like chromatin in the cell: What can we learn from imaging and computational modeling? Curr Opin Struct Biol 2021; 71:123-135. [PMID: 34303931 DOI: 10.1016/j.sbi.2021.06.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 06/08/2021] [Indexed: 12/23/2022]
Abstract
Chromatin in eukaryotic cells is a negatively charged long polymer consisting of DNA, histones, and various associated proteins. With its highly charged and heterogeneous nature, chromatin structure varies greatly depending on various factors (e.g. chemical modifications and protein enrichment) and the surrounding environment (e.g. cations): from a 10-nm fiber, a folded 30-nm fiber, to chromatin condensates/droplets. Recent advanced imaging has observed that chromatin exhibits a dynamic liquid-like behavior and undergoes structural variations within the cell. Current computational modeling has made it possible to reconstruct the liquid-like chromatin in the cell by dealing with a number of nucleosomes on multiscale levels and has become a powerful technique to inspect the molecular mechanisms giving rise to the observed behavior, which imaging methods cannot do on their own. Based on new findings from both imaging and modeling studies, we discuss the dynamic aspect of chromatin in living cells and its functional relevance.
Collapse
Affiliation(s)
- Yuji Itoh
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
| | - Esmae J Woods
- Maxwell Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, UK
| | - Katsuhiko Minami
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan; Department of Genetics, School of Life Science, Sokendai (Graduate University for Advanced Studies), Mishima, Shizuoka 411-8540, Japan
| | - Kazuhiro Maeshima
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan; Department of Genetics, School of Life Science, Sokendai (Graduate University for Advanced Studies), Mishima, Shizuoka 411-8540, Japan.
| | - Rosana Collepardo-Guevara
- Maxwell Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, UK; Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK; Department of Genetics, University of Cambridge, Cambridge, CB2 3EH, UK.
| |
Collapse
|
37
|
Moretti C, Stévant I, Ghavi-Helm Y. 3D genome organisation in Drosophila. Brief Funct Genomics 2021; 19:92-100. [PMID: 31796947 DOI: 10.1093/bfgp/elz029] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 08/02/2019] [Accepted: 09/20/2019] [Indexed: 12/17/2022] Open
Abstract
Ever since Thomas Hunt Morgan's discovery of the chromosomal basis of inheritance by using Drosophila melanogaster as a model organism, the fruit fly has remained an essential model system in studies of genome biology, including chromatin organisation. Very much as in vertebrates, in Drosophila, the genome is organised in territories, compartments and topologically associating domains (TADs). However, these domains might be formed through a slightly different mechanism than in vertebrates due to the presence of a large and potentially redundant set of insulator proteins and the minor role of dCTCF in TAD boundary formation. Here, we review the different levels of chromatin organisation in Drosophila and discuss mechanisms and factors that might be involved in TAD formation. The dynamics of TADs and enhancer-promoter interactions in the context of transcription are covered in the light of currently conflicting results. Finally, we illustrate the value of polymer modelling approaches to infer the principles governing the three-dimensional organisation of the Drosophila genome.
Collapse
Affiliation(s)
- Charlotte Moretti
- Institut de Génomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, 46 allée d'Italie F-69364 Lyon, France
| | - Isabelle Stévant
- Institut de Génomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, 46 allée d'Italie F-69364 Lyon, France
| | - Yad Ghavi-Helm
- Institut de Génomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, 46 allée d'Italie F-69364 Lyon, France
| |
Collapse
|
38
|
Abstract
The cell nucleus is best known as the container of the genome. Its envelope provides a barrier for passive macromolecule diffusion, which enhances the control of gene expression. As its largest and stiffest organelle, the nucleus also defines the minimal space requirements of a cell. Internal or external pressures that deform a cell to its physical limits cause a corresponding nuclear deformation. Evidence is consolidating that the nucleus, in addition to its genetic functions, serves as a physical sensing device for critical cell body deformation. Nuclear mechanotransduction allows cells to adapt their acute behaviors, mechanical stability, paracrine signaling, and fate to their physical surroundings. This review summarizes the basic chemical and mechanical properties of nuclear components, and how these properties are thought to be utilized for mechanosensing. Expected final online publication date for the Annual Review of Cell and Developmental Biology, Volume 37 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
Collapse
Affiliation(s)
- Philipp Niethammer
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA;
| |
Collapse
|
39
|
Abstract
Genomic information is encoded on long strands of DNA, which are folded into chromatin and stored in a tiny nucleus. Nuclear chromatin is a negatively charged polymer composed of DNA, histones, and various nonhistone proteins. Because of its highly charged nature, chromatin structure varies greatly depending on the surrounding environment (e.g., cations, molecular crowding, etc.). New technologies to capture chromatin in living cells have been developed over the past 10 years. Our view on chromatin organization has drastically shifted from a regular and static one to a more variable and dynamic one. Chromatin forms numerous compact dynamic domains that act as functional units of the genome in higher eukaryotic cells and locally appear liquid-like. By changing DNA accessibility, these domains can govern various functions. Based on new evidences from versatile genomics and advanced imaging studies, we discuss the physical nature of chromatin in the crowded nuclear environment and how it is regulated.
Collapse
Affiliation(s)
- Kazuhiro Maeshima
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
- Department of Genetics, School of Life Science, Sokendai (Graduate University for Advanced Studies), Mishima, Shizuoka 411-8540, Japan
| | - Shiori Iida
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
- Department of Genetics, School of Life Science, Sokendai (Graduate University for Advanced Studies), Mishima, Shizuoka 411-8540, Japan
| | - Sachiko Tamura
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
| |
Collapse
|
40
|
Deolal P, Male G, Mishra K. The challenge of staying in shape: nuclear size matters. Curr Genet 2021; 67:605-612. [PMID: 33779777 DOI: 10.1007/s00294-021-01176-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 03/06/2021] [Accepted: 03/08/2021] [Indexed: 10/21/2022]
Abstract
Cellular organelles have unique morphology and the organelle size to cell size ratio is regulated. Nucleus is one of the most prominent, usually round in shape, organelle of a eukaryotic cell that occupies 8-10% of cellular volume. The shape and size of nucleus is known to undergo remodeling during processes such as cell growth, division and certain stresses. Regulation of protein and lipid distribution at the nuclear envelope is crucial for preserving the nuclear morphology and size. As size and morphology are interlinked, altering one influences the other. In this perspective, we discuss the relationship between size and shape regulation of the nucleus.
Collapse
Affiliation(s)
- Pallavi Deolal
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, 500046, India
| | - Gurranna Male
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, 500046, India
| | - Krishnaveni Mishra
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, 500046, India.
| |
Collapse
|
41
|
dos Santos Á, Toseland CP. Regulation of Nuclear Mechanics and the Impact on DNA Damage. Int J Mol Sci 2021; 22:3178. [PMID: 33804722 PMCID: PMC8003950 DOI: 10.3390/ijms22063178] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 03/15/2021] [Accepted: 03/18/2021] [Indexed: 02/06/2023] Open
Abstract
In eukaryotic cells, the nucleus houses the genomic material of the cell. The physical properties of the nucleus and its ability to sense external mechanical cues are tightly linked to the regulation of cellular events, such as gene expression. Nuclear mechanics and morphology are altered in many diseases such as cancer and premature ageing syndromes. Therefore, it is important to understand how different components contribute to nuclear processes, organisation and mechanics, and how they are misregulated in disease. Although, over the years, studies have focused on the nuclear lamina-a mesh of intermediate filament proteins residing between the chromatin and the nuclear membrane-there is growing evidence that chromatin structure and factors that regulate chromatin organisation are essential contributors to the physical properties of the nucleus. Here, we review the main structural components that contribute to the mechanical properties of the nucleus, with particular emphasis on chromatin structure. We also provide an example of how nuclear stiffness can both impact and be affected by cellular processes such as DNA damage and repair.
Collapse
Affiliation(s)
- Ália dos Santos
- Department of Oncology and Metabolism, University of Sheffield, Sheffield S10 2RX, UK
| | - Christopher P. Toseland
- Department of Oncology and Metabolism, University of Sheffield, Sheffield S10 2RX, UK
- Insigneo Institute for in Silico Medicine, University of Sheffield, Sheffield S10 2RX, UK
| |
Collapse
|
42
|
Strickfaden H, Tolsma TO, Sharma A, Underhill DA, Hansen JC, Hendzel MJ. Condensed Chromatin Behaves like a Solid on the Mesoscale In Vitro and in Living Cells. Cell 2020; 183:1772-1784.e13. [PMID: 33326747 DOI: 10.1016/j.cell.2020.11.027] [Citation(s) in RCA: 156] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 09/16/2020] [Accepted: 11/16/2020] [Indexed: 12/11/2022]
Abstract
The association of nuclear DNA with histones to form chromatin is essential for temporal and spatial control of eukaryotic genomes. In this study, we examined the physical state of condensed chromatin in vitro and in vivo. Our in vitro studies demonstrate that self-association of nucleosomal arrays under a wide range of solution conditions produces supramolecular condensates in which the chromatin is physically constrained and solid-like. By measuring DNA mobility in living cells, we show that condensed chromatin also exhibits solid-like behavior in vivo. Representative heterochromatin proteins, however, display liquid-like behavior and coalesce around the solid chromatin scaffold. Importantly, euchromatin and heterochromatin show solid-like behavior even under conditions that produce limited interactions between chromatin fibers. Our results reveal that condensed chromatin exists in a solid-like state whose properties resist external forces and create an elastic gel and provides a scaffold that supports liquid-liquid phase separation of chromatin binding proteins.
Collapse
Affiliation(s)
- Hilmar Strickfaden
- Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Thomas O Tolsma
- Department of Biochemistry and Molecular Biology, College of Natural Sciences, Colorado State University, Fort Collins, CO, USA
| | - Ajit Sharma
- Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - D Alan Underhill
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada; Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Jeffrey C Hansen
- Department of Biochemistry and Molecular Biology, College of Natural Sciences, Colorado State University, Fort Collins, CO, USA.
| | - Michael J Hendzel
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada; Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.
| |
Collapse
|
43
|
Strickfaden H. Reflections on the organization and the physical state of chromatin in eukaryotic cells. Genome 2020; 64:311-325. [PMID: 33306433 DOI: 10.1139/gen-2020-0132] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
In recent years, our perception of chromatin structure and organization in the cell nucleus has changed in fundamental ways. The 30 nm chromatin fiber has lost its status as an essential in vivo structure. Hi-C and related biochemical methods, advanced electron and super-resolved fluorescence microscopy, together with concepts from soft matter physics, have revolutionized the field. A comprehensive understanding of the structural and functional interactions that regulate cell cycle and cell type specific nuclear functions appears within reach, but it requires the integration of top-down and bottom-up approachs. In this review, I present an update on nuclear architecture studies with an emphasis on organization and the controversy regarding the physical state of chromatin in cells.
Collapse
Affiliation(s)
- Hilmar Strickfaden
- Departments of Cell Biology and Oncology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.,Departments of Cell Biology and Oncology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| |
Collapse
|
44
|
Heijo H, Shimogama S, Nakano S, Miyata A, Iwao Y, Hara Y. DNA content contributes to nuclear size control in Xenopus laevis. Mol Biol Cell 2020; 31:2703-2717. [PMID: 32997613 PMCID: PMC7927187 DOI: 10.1091/mbc.e20-02-0113] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 08/28/2020] [Accepted: 09/25/2020] [Indexed: 12/17/2022] Open
Abstract
Cells adapt to drastic changes in genome quantity during evolution and cell division by adjusting the nuclear size to exert genomic functions. However, the mechanism by which DNA content within the nucleus contributes to controlling the nuclear size remains unclear. Here, we experimentally evaluated the effects of DNA content by utilizing cell-free Xenopus egg extracts and imaging of in vivo embryos. Upon manipulation of DNA content while maintaining cytoplasmic effects constant, both plateau size and expansion speed of the nucleus correlated highly with DNA content. We also found that nuclear expansion dynamics was altered when chromatin interaction with the nuclear envelope or chromatin condensation was manipulated while maintaining DNA content constant. Furthermore, excess membrane accumulated on the nuclear surface when the DNA content was low. These results clearly demonstrate that nuclear expansion is determined not only by cytoplasmic membrane supply but also by the physical properties of chromatin, including DNA quantity and chromatin structure within the nucleus, rather than the coding sequences themselves. In controlling the dynamics of nuclear expansion, we propose that chromatin interaction with the nuclear envelope plays a role in transmitting chromatin repulsion forces to the nuclear membrane.
Collapse
Affiliation(s)
- Hiroko Heijo
- Evolutionary Cell Biology Laboratory, Faculty of Science, Yamaguchi University, Yoshida 1677-1, Yamaguchi City, 753-8512, Japan
| | - Sora Shimogama
- Evolutionary Cell Biology Laboratory, Faculty of Science, Yamaguchi University, Yoshida 1677-1, Yamaguchi City, 753-8512, Japan
| | - Shuichi Nakano
- Evolutionary Cell Biology Laboratory, Faculty of Science, Yamaguchi University, Yoshida 1677-1, Yamaguchi City, 753-8512, Japan
| | - Anna Miyata
- Evolutionary Cell Biology Laboratory, Faculty of Science, Yamaguchi University, Yoshida 1677-1, Yamaguchi City, 753-8512, Japan
| | - Yasuhiro Iwao
- Laboratory of Molecular Developmental Biology, Department of Biology, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yoshida 1677-1, Yamaguchi City, 753-8512, Japan
| | - Yuki Hara
- Evolutionary Cell Biology Laboratory, Faculty of Science, Yamaguchi University, Yoshida 1677-1, Yamaguchi City, 753-8512, Japan
| |
Collapse
|
45
|
Hobson CM, Kern M, O'Brien ET, Stephens AD, Falvo MR, Superfine R. Correlating nuclear morphology and external force with combined atomic force microscopy and light sheet imaging separates roles of chromatin and lamin A/C in nuclear mechanics. Mol Biol Cell 2020; 31:1788-1801. [PMID: 32267206 DOI: 10.1101/2020.02.10.942581] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023] Open
Abstract
Nuclei are often under external stress, be it during migration through tight constrictions or compressive pressure by the actin cap, and the mechanical properties of nuclei govern their subsequent deformations. Both altered mechanical properties of nuclei and abnormal nuclear morphologies are hallmarks of a variety of disease states. Little work, however, has been done to link specific changes in nuclear shape to external forces. Here, we utilize a combined atomic force microscope and light sheet microscope to show SKOV3 nuclei exhibit a two-regime force response that correlates with changes in nuclear volume and surface area, allowing us to develop an empirical model of nuclear deformation. Our technique further decouples the roles of chromatin and lamin A/C in compression, showing they separately resist changes in nuclear volume and surface area, respectively; this insight was not previously accessible by Hertzian analysis. A two-material finite element model supports our conclusions. We also observed that chromatin decompaction leads to lower nuclear curvature under compression, which is important for maintaining nuclear compartmentalization and function. The demonstrated link between specific types of nuclear morphological change and applied force will allow researchers to better understand the stress on nuclei throughout various biological processes.
Collapse
Affiliation(s)
- Chad M Hobson
- Department of Physics and Astronomy, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Megan Kern
- Department of Physics and Astronomy, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - E Timothy O'Brien
- Department of Physics and Astronomy, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Andrew D Stephens
- Biology Department, The University of Massachusetts at Amherst, Amherst, MA 01003, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Michael R Falvo
- Department of Physics and Astronomy, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Richard Superfine
- Department of Applied Physical Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| |
Collapse
|
46
|
Hobson CM, Kern M, O’Brien ET, Stephens AD, Falvo MR, Superfine R. Correlating nuclear morphology and external force with combined atomic force microscopy and light sheet imaging separates roles of chromatin and lamin A/C in nuclear mechanics. Mol Biol Cell 2020; 31:1788-1801. [PMID: 32267206 PMCID: PMC7521857 DOI: 10.1091/mbc.e20-01-0073] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 03/23/2020] [Accepted: 03/31/2020] [Indexed: 12/31/2022] Open
Abstract
Nuclei are often under external stress, be it during migration through tight constrictions or compressive pressure by the actin cap, and the mechanical properties of nuclei govern their subsequent deformations. Both altered mechanical properties of nuclei and abnormal nuclear morphologies are hallmarks of a variety of disease states. Little work, however, has been done to link specific changes in nuclear shape to external forces. Here, we utilize a combined atomic force microscope and light sheet microscope to show SKOV3 nuclei exhibit a two-regime force response that correlates with changes in nuclear volume and surface area, allowing us to develop an empirical model of nuclear deformation. Our technique further decouples the roles of chromatin and lamin A/C in compression, showing they separately resist changes in nuclear volume and surface area, respectively; this insight was not previously accessible by Hertzian analysis. A two-material finite element model supports our conclusions. We also observed that chromatin decompaction leads to lower nuclear curvature under compression, which is important for maintaining nuclear compartmentalization and function. The demonstrated link between specific types of nuclear morphological change and applied force will allow researchers to better understand the stress on nuclei throughout various biological processes.
Collapse
Affiliation(s)
- Chad M. Hobson
- Department of Physics and Astronomy, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Megan Kern
- Department of Physics and Astronomy, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - E. Timothy O’Brien
- Department of Physics and Astronomy, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Andrew D. Stephens
- Biology Department, The University of Massachusetts at Amherst, Amherst, MA 01003, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Michael R. Falvo
- Department of Physics and Astronomy, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Richard Superfine
- Department of Applied Physical Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| |
Collapse
|
47
|
Hobson CM, Stephens AD. Modeling of Cell Nuclear Mechanics: Classes, Components, and Applications. Cells 2020; 9:E1623. [PMID: 32640571 PMCID: PMC7408412 DOI: 10.3390/cells9071623] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 06/25/2020] [Accepted: 07/02/2020] [Indexed: 12/22/2022] Open
Abstract
Cell nuclei are paramount for both cellular function and mechanical stability. These two roles of nuclei are intertwined as altered mechanical properties of nuclei are associated with altered cell behavior and disease. To further understand the mechanical properties of cell nuclei and guide future experiments, many investigators have turned to mechanical modeling. Here, we provide a comprehensive review of mechanical modeling of cell nuclei with an emphasis on the role of the nuclear lamina in hopes of spurring future growth of this field. The goal of this review is to provide an introduction to mechanical modeling techniques, highlight current applications to nuclear mechanics, and give insight into future directions of mechanical modeling. There are three main classes of mechanical models-schematic, continuum mechanics, and molecular dynamics-which provide unique advantages and limitations. Current experimental understanding of the roles of the cytoskeleton, the nuclear lamina, and the chromatin in nuclear mechanics provide the basis for how each component is subsequently treated in mechanical models. Modeling allows us to interpret assay-specific experimental results for key parameters and quantitatively predict emergent behaviors. This is specifically powerful when emergent phenomena, such as lamin-based strain stiffening, can be deduced from complimentary experimental techniques. Modeling differences in force application, geometry, or composition can additionally clarify seemingly conflicting experimental results. Using these approaches, mechanical models have informed our understanding of relevant biological processes such as migration, nuclear blebbing, nuclear rupture, and cell spreading and detachment. There remain many aspects of nuclear mechanics for which additional mechanical modeling could provide immediate insight. Although mechanical modeling of cell nuclei has been employed for over a decade, there are still relatively few models for any given biological phenomenon. This implies that an influx of research into this realm of the field has the potential to dramatically shape both future experiments and our current understanding of nuclear mechanics, function, and disease.
Collapse
Affiliation(s)
- Chad M. Hobson
- Department of Physics and Astronomy, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Andrew D. Stephens
- Biology Department, The University of Massachusetts at Amherst, Amherst, MA 01003, USA
| |
Collapse
|
48
|
Abstract
The size of the intracellular structure that encloses genomic DNA - known as the nucleus in eukaryotes and nucleoid in prokaryotes - is believed to scale according to cell size and genomic content inside them across the tree of life. However, an actual scaling relationship remains largely unexplored across eukaryotic species. Here, I collected a large dataset of nuclear and cell volumes in diverse species across different phyla, including some prokaryotes, from the published literature and assessed the scaling relationship. Although entire inter-species data showed that nuclear volume correlates with cell volume, the quantitative scaling property exhibited differences among prokaryotes, unicellular eukaryotes and multicellular eukaryotes. Additionally, the nuclear volume correlates with genomic content inside the nucleus of multicellular eukaryotes but not of prokaryotes and unicellular eukaryotes. In this Hypothesis, I, thus, propose that the basic concept of nuclear-size scaling is conserved across eukaryotes; however, structural and mechanical properties of nuclear membranes and chromatin can result in different scaling relationships of nuclear volume to cell volume and genomic content among species. In particular, eukaryote-specific properties of the nuclear membrane may contribute to the extreme flexibility of nuclear size with regard to DNA density inside the nucleus.
Collapse
Affiliation(s)
- Yuki Hara
- Evolutionary Cell Biology Laboratory, Faculty of Science, Yamaguchi University, Yoshida 1677-1, Yamaguchi city 753-8512, Japan
| |
Collapse
|
49
|
Zuela-Sopilniak N, Bar-Sela D, Charar C, Wintner O, Gruenbaum Y, Buxboim A. Measuring nucleus mechanics within a living multicellular organism: Physical decoupling and attenuated recovery rate are physiological protective mechanisms of the cell nucleus under high mechanical load. Mol Biol Cell 2020; 31:1943-1950. [PMID: 32583745 PMCID: PMC7525816 DOI: 10.1091/mbc.e20-01-0085] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Nuclei within cells are constantly subjected to compressive, tensile, and shear forces, which regulate nucleoskeletal and cytoskeletal remodeling, activate signaling pathways, and direct cell-fate decisions. Multiple rheological methods have been adapted for characterizing the response to applied forces of isolated nuclei and nuclei within intact cells. However, in vitro measurements fail to capture the viscoelastic modulation of nuclear stress-strain relationships by the physiological tethering to the surrounding cytoskeleton, extracellular matrix and cells, and tissue-level architectures. Using an equiaxial stretching apparatus, we applied a step stress and measured nucleus deformation dynamics within living Caenorhabditis elegans nematodes. Nuclei deformed nonmonotonically under constant load. Nonmonotonic deformation was conserved across tissues and robust to nucleoskeletal and cytoskeletal perturbations, but it required intact linker of nucleoskeleton and cytoskeleton complex attachments. The transition from creep to strain recovery fits a tensile-compressive linear viscoelastic model that is indicative of nucleoskeletal–cytoskeletal decoupling under high load. Ce-lamin (lmn-1) knockdown softened the nucleus, whereas nematode aging stiffened the nucleus and decreased deformation recovery rate. Recovery lasted minutes rather than seconds due to physiological damping of the released mechanical energy, thus protecting nuclear integrity and preventing chromatin damage.
Collapse
Affiliation(s)
- Noam Zuela-Sopilniak
- Departments of Genetics, Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Daniel Bar-Sela
- Cell and Developmental Biology, The Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Chayki Charar
- Departments of Genetics, Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Oren Wintner
- Cell and Developmental Biology, The Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Yosef Gruenbaum
- Departments of Genetics, Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Amnon Buxboim
- Cell and Developmental Biology, The Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem 9190401, Israel.,Alexander Grass Center for Bioengineering, The Rachel and Selim Benin School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem 9190416, Israel
| |
Collapse
|
50
|
Dreger M, Madrazo E, Hurlstone A, Redondo-Muñoz J. Novel contribution of epigenetic changes to nuclear dynamics. Nucleus 2020; 10:42-47. [PMID: 30784352 PMCID: PMC6527383 DOI: 10.1080/19491034.2019.1580100] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Migrating cells have to cross many physical barriers and confined in 3D environments. The surrounding environment promotes mechano- and biological signals that orchestrate cellular changes, such as cytoskeletal and adhesion rearrangements and proteolytic digestion. Recent studies provide new insights into how the nucleus must alter its shape, localization and mechanical properties in order to promote nuclear deformability, chromatin compaction and gene reprogramming. It is known that the chromatin structure contributes directly to genomic and non-genomic functions, such as gene transcription and the physical properties of the nucleus. Here, we appraise paradigms and novel insights regarding the functional role of chromatin during nuclear deformation. In so doing, we review how constraint and mechanical conditions influence the structure, localization and chromatin decompaction. Finally, we highlight the emerging roles of mechanogenomics and the molecular basis of nucleoskeletal components, which open unexplored territory to understand how cells regulate their chromatin and modify the nucleus.
Collapse
Affiliation(s)
- Marcel Dreger
- a Faculty of Biology, Medicine and Health, Division of Cancer Studies , School of Medical Sciences, The University of Manchester , Manchester , UK
| | - Elena Madrazo
- b Department of Immunology Ophthalmology and ENT, Hospital 12 de Octubre Health Research Institute (imas12) , Complutense University, School of Medicine , Madrid , Spain
| | - Adam Hurlstone
- a Faculty of Biology, Medicine and Health, Division of Cancer Studies , School of Medical Sciences, The University of Manchester , Manchester , UK
| | - Javier Redondo-Muñoz
- b Department of Immunology Ophthalmology and ENT, Hospital 12 de Octubre Health Research Institute (imas12) , Complutense University, School of Medicine , Madrid , Spain.,c Lydia Becker Institute for Inflammation and Immunity , The University of Manchester , Manchester , UK
| |
Collapse
|