1
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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 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] [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.
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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
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2
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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 2024:10.1007/s00412-024-00817-x. [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] [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.
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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.
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3
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Bunner S, Prince K, Srikrishna K, Pujadas EM, McCarthy AA, Kuklinski A, Jackson O, Pellegrino P, Jagtap S, Eweka I, Lawlor C, Eastin E, Yas G, Aiello J, LaPointe N, von Blucher IS, Hardy J, Chen J, Backman V, Janssen A, Packard M, Dorfman K, Almassalha L, Bahiru MS, Stephens AD. DNA density is a better indicator of a nuclear bleb than lamin B loss. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.06.579152. [PMID: 38370828 PMCID: PMC10871186 DOI: 10.1101/2024.02.06.579152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Nuclear blebs are herniations of the nucleus that occur in diseased nuclei that cause nuclear rupture leading to cellular dysfunction. Chromatin and lamins are two of the major structural components of the nucleus that maintain its shape and function, but their relative roles in nuclear blebbing remain elusive. Lamin B is reported to be lost in blebs by qualitative data while quantitative studies reveal a spectrum of lamin B levels in nuclear blebs dependent on perturbation and cell type. Chromatin has been reported to be decreased or de-compacted in nuclear blebs, but again the data are not conclusive. To determine the composition of nuclear blebs, we compared the immunofluorescence intensity of lamin B and DNA in the main nucleus body and nuclear bleb across cell types and perturbations. Lamin B nuclear bleb levels varied drastically across MEF wild type and chromatin or lamins perturbations, HCT116 lamin B1-GFP imaging, and human disease model cells of progeria and prostate cancer. However, DNA concentration was consistently decreased to about half that of the main nucleus body across all measured conditions. Using Partial Wave Spectroscopic (PWS) microscopy to measure chromatin density in the nuclear bleb vs body we find similar results that DNA is consistently less dense in nuclear blebs. Thus, our data spanning many different cell types and perturbations supports that decreased DNA is a better marker of a nuclear bleb than lamin B levels that vary widely.
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Affiliation(s)
- Samantha Bunner
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Kelsey Prince
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Karan Srikrishna
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Emily Marie Pujadas
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
- IBIS Interdisciplinary Biological Sciences Graduate Program, Northwestern University, Evanston, IL 60208, USA
| | | | - Anna Kuklinski
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Olivia Jackson
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Pedro Pellegrino
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Shrushti Jagtap
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Imuetiyan Eweka
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Colman Lawlor
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Emma Eastin
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Griffin Yas
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Julianna Aiello
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Nathan LaPointe
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | | | - Jillian Hardy
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Jason Chen
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Vadim Backman
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Anne Janssen
- School of Biological Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Mary Packard
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Katherine Dorfman
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Luay Almassalha
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Michael Seifu Bahiru
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
- Program in Neuroscience and Behavior, University of Massachusetts, Amherst, MA 01003, USA
| | - A. D. Stephens
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
- Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA
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4
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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.
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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
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5
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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.
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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
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6
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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.
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7
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Wallace M, Fedorchak GR, Agrawal R, Gilbert RM, Patel J, Park S, Paszek M, Lammerding J. The lamin A/C Ig-fold undergoes cell density-dependent changes that alter epitope binding. Nucleus 2023; 14:2180206. [PMID: 36809122 PMCID: PMC9980629 DOI: 10.1080/19491034.2023.2180206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023] Open
Abstract
Lamins A/C are nuclear intermediate filament proteins that are involved in diverse cellular mechanical and biochemical functions. Here, we report that recognition of Lamins A/C by a commonly used antibody (JOL-2) that binds the Lamin A/C Ig-fold and other antibodies targeting similar epitopes is highly dependent on cell density, even though Lamin A/Clevels do not change. We propose that the effect is caused by partial unfolding or masking of the C'E and/or EF loops of the Ig-fold in response to cell spreading. Surprisingly, JOL-2 antibody labeling was insensitive to disruption of cytoskeletal filaments or the Linker of Nucleoskeleton and Cytoskeleton (LINC) complex. Furthermore, neither nuclear stiffness nor nucleo-cytoskeletal force transmission changed with cell density. These findings are important for the interpretation of immunofluorescence data for Lamin A/C and also raise the intriguing prospect that the conformational changes may play a role in Lamin A/C mediated cellular function.
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Affiliation(s)
- Melanie Wallace
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA,Weill Institute for Cell and Molecular Biology, Ithaca, NY, USA
| | - Gregory R. Fedorchak
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA,Weill Institute for Cell and Molecular Biology, Ithaca, NY, USA
| | - Richa Agrawal
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA,Weill Institute for Cell and Molecular Biology, Ithaca, NY, USA
| | - Rachel M. Gilbert
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA,Weill Institute for Cell and Molecular Biology, Ithaca, NY, USA
| | - Jineet Patel
- Weill Institute for Cell and Molecular Biology, Ithaca, NY, USA
| | - Sangwoo Park
- Graduate Field of Biophysics, Cornell University, Ithaca, NY, USA
| | - Matthew Paszek
- Graduate Field of Biophysics, Cornell University, Ithaca, NY, USA,Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, USA
| | - Jan Lammerding
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA,Weill Institute for Cell and Molecular Biology, Ithaca, NY, USA,CONTACT Jan Lammerding Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY14853, USA
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8
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Turkmen AM, Saik NO, Ullman KS. The dynamic nuclear envelope: resilience in health and dysfunction in disease. Curr Opin Cell Biol 2023; 85:102230. [PMID: 37660480 PMCID: PMC10843620 DOI: 10.1016/j.ceb.2023.102230] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 08/01/2023] [Accepted: 08/02/2023] [Indexed: 09/05/2023]
Abstract
The canonical appearance of the nucleus depends on constant adaptation and remodeling of the nuclear envelope in response to changing biomechanical forces and metabolic demands. Dynamic events at the nuclear envelope play a vital role in supporting key nuclear functions as well as conferring plasticity to this organelle. Moreover, imbalance of these dynamic processes is emerging as a central feature of disease etiology. This review focuses on recent advances that shed light on the myriad events at the nuclear envelope that contribute to resilience and flexibility in nuclear architecture.
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Affiliation(s)
- Ayse M Turkmen
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112, USA
| | - Natasha O Saik
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112, USA
| | - Katharine S Ullman
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112, USA.
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9
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Salafranca J, Ko JK, Mukherjee AK, Fritzsche M, van Grinsven E, Udalova IA. Neutrophil nucleus: shaping the past and the future. J Leukoc Biol 2023; 114:585-594. [PMID: 37480361 PMCID: PMC10673716 DOI: 10.1093/jleuko/qiad084] [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: 03/21/2023] [Revised: 07/10/2023] [Accepted: 07/12/2023] [Indexed: 07/24/2023] Open
Abstract
Neutrophils are innate immune cells that are key to protecting the host against infection and maintaining body homeostasis. However, if dysregulated, they can contribute to disease, such as in cancer or chronic autoinflammatory disorders. Recent studies have highlighted the heterogeneity in the neutrophil compartment and identified the presence of immature neutrophils and their precursors in these pathologies. Therefore, understanding neutrophil maturity and the mechanisms through which they contribute to disease is critical. Neutrophils were first characterized morphologically by Ehrlich in 1879 using microscopy, and since then, different technologies have been used to assess neutrophil maturity. The advances in the imaging field, including state-of-the-art microscopy and machine learning algorithms for image analysis, reinforce the use of neutrophil nuclear morphology as a fundamental marker of maturity, applicable for objective classification in clinical diagnostics. New emerging approaches, such as the capture of changes in chromatin topology, will provide mechanistic links between the nuclear shape, chromatin organization, and transcriptional regulation during neutrophil maturation.
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Affiliation(s)
- Julia Salafranca
- The Kennedy Institute of Rheumatology, University of Oxford, Old Road Campus Research Build, Roosevelt Dr, Headington, Oxford OX3 7DQ, United Kingdom
| | - Jacky Ka Ko
- The Kennedy Institute of Rheumatology, University of Oxford, Old Road Campus Research Build, Roosevelt Dr, Headington, Oxford OX3 7DQ, United Kingdom
| | - Ananda K Mukherjee
- The Kennedy Institute of Rheumatology, University of Oxford, Old Road Campus Research Build, Roosevelt Dr, Headington, Oxford OX3 7DQ, United Kingdom
| | - Marco Fritzsche
- The Kennedy Institute of Rheumatology, University of Oxford, Old Road Campus Research Build, Roosevelt Dr, Headington, Oxford OX3 7DQ, United Kingdom
| | - Erinke van Grinsven
- The Kennedy Institute of Rheumatology, University of Oxford, Old Road Campus Research Build, Roosevelt Dr, Headington, Oxford OX3 7DQ, United Kingdom
| | - Irina A Udalova
- The Kennedy Institute of Rheumatology, University of Oxford, Old Road Campus Research Build, Roosevelt Dr, Headington, Oxford OX3 7DQ, United Kingdom
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10
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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: 4] [Impact Index Per Article: 4.0] [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.
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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
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11
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de Lope-Planelles A, González-Novo R, Madrazo E, Peralta-Carrero G, Cruz Rodríguez MP, Zamora-Carreras H, Torrano V, López-Menéndez H, Roda-Navarro P, Monroy F, Redondo-Muñoz J. Mechanical stress confers nuclear and functional changes in derived leukemia cells from persistent confined migration. Cell Mol Life Sci 2023; 80:316. [PMID: 37801090 PMCID: PMC10558412 DOI: 10.1007/s00018-023-04968-5] [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: 03/14/2023] [Revised: 08/07/2023] [Accepted: 09/14/2023] [Indexed: 10/07/2023]
Abstract
Nuclear deformability plays a critical role in cell migration. During this process, the remodeling of internal components of the nucleus has a direct impact on DNA damage and cell behavior; however, how persistent migration promotes nuclear changes leading to phenotypical and functional consequences remains poorly understood. Here, we described that the persistent migration through physical barriers was sufficient to promote permanent modifications in migratory-altered cells. We found that derived cells from confined migration showed changes in lamin B1 localization, cell morphology and transcription. Further analysis confirmed that migratory-altered cells showed functional differences in DNA repair, cell response to chemotherapy and cell migration in vivo homing experiments. Experimental modulation of actin polymerization affected the redistribution of lamin B1, and the basal levels of DNA damage in migratory-altered cells. Finally, since major nuclear changes were present in migratory-altered cells, we applied a multidisciplinary biochemical and biophysical approach to identify that confined conditions promoted a different biomechanical response of the nucleus in migratory-altered cells. Our observations suggest that mechanical compression during persistent cell migration has a role in stable nuclear and genomic alterations that might handle the genetic instability and cellular heterogeneity in aging diseases and cancer.
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Affiliation(s)
- Ana de Lope-Planelles
- Department of Molecular Medicine, Centro de Investigaciones Biológicas Margarita Salas (CIB Margarita Salas-CSIC), Madrid, Spain
| | - Raquel González-Novo
- Department of Molecular Medicine, Centro de Investigaciones Biológicas Margarita Salas (CIB Margarita Salas-CSIC), Madrid, Spain
| | - Elena Madrazo
- Department of Molecular Medicine, Centro de Investigaciones Biológicas Margarita Salas (CIB Margarita Salas-CSIC), Madrid, Spain
| | - Gracia Peralta-Carrero
- Department of Molecular Medicine, Centro de Investigaciones Biológicas Margarita Salas (CIB Margarita Salas-CSIC), Madrid, Spain
| | - María Pilar Cruz Rodríguez
- Department of Molecular Medicine, Centro de Investigaciones Biológicas Margarita Salas (CIB Margarita Salas-CSIC), Madrid, Spain
| | - Héctor Zamora-Carreras
- Department of Molecular Medicine, Centro de Investigaciones Biológicas Margarita Salas (CIB Margarita Salas-CSIC), Madrid, Spain
| | - Verónica Torrano
- Department of Biochemistry and Molecular Biology, University of the Basque Country, Leioa, Spain
| | - Horacio López-Menéndez
- Department of Physical Chemistry, Complutense University, Madrid, Spain
- Translational Biophysics, Hospital Doce de Octubre Health Research Institute (imas12), Madrid, Spain
| | - Pedro Roda-Navarro
- Department of Immunology, School of Medicine, University Complutense de Madrid and 12 de Octubre Health Research Institute (Imas12) Madrid, Madrid, Spain
| | - Francisco Monroy
- Department of Physical Chemistry, Complutense University, Madrid, Spain
- Translational Biophysics, Hospital Doce de Octubre Health Research Institute (imas12), Madrid, Spain
| | - Javier Redondo-Muñoz
- Department of Molecular Medicine, Centro de Investigaciones Biológicas Margarita Salas (CIB Margarita Salas-CSIC), Madrid, Spain.
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12
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Negri ML, D'Annunzio S, Vitali G, Zippo A. May the force be with you: Nuclear condensates function beyond transcription control: Potential nongenetic functions of nuclear condensates in physiological and pathological conditions. Bioessays 2023; 45:e2300075. [PMID: 37530178 DOI: 10.1002/bies.202300075] [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: 04/30/2023] [Revised: 07/03/2023] [Accepted: 07/13/2023] [Indexed: 08/03/2023]
Abstract
Over the past decade, research has revealed biomolecular condensates' relevance in diverse cellular functions. Through a phase separation process, they concentrate macromolecules in subcompartments shaping the cellular organization and physiology. In the nucleus, biomolecular condensates assemble relevant biomolecules that orchestrate gene expression. We here hypothesize that chromatin condensates can also modulate the nongenetic functions of the genome, including the nuclear mechanical properties. The importance of chromatin condensates is supported by the genetic evidence indicating that mutations in their members are causative of a group of rare Mendelian diseases named chromatinopathies (CPs). Despite a broad spectrum of clinical features and the perturbations of the epigenetic machinery characterizing the CPs, recent findings highlighted negligible changes in gene expression. These data argue in favor of possible noncanonical functions of chromatin condensates in regulating the genome's spatial organization and, consequently, the nuclear mechanics. In this review, we discuss how condensates may impact nuclear mechanical properties, thus affecting the cellular response to mechanical cues and, eventually, cell fate and identity. Chromatin condensates organize macromolecules in the nucleus orchestrating the transcription regulation and mutations in their members are responsible for rare diseases named chromatinopathies. We argue that chromatin condensates, in concert with the nuclear lamina, may also govern the nuclear mechanical properties affecting the cellular response to external cues.
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Affiliation(s)
- Maria Luce Negri
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Sarah D'Annunzio
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Giulia Vitali
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Alessio Zippo
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, Italy
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13
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Bastianello G, Foiani M. Mechanisms controlling the mechanical properties of the nuclei. Curr Opin Cell Biol 2023; 84:102222. [PMID: 37619290 DOI: 10.1016/j.ceb.2023.102222] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 07/28/2023] [Accepted: 07/29/2023] [Indexed: 08/26/2023]
Abstract
The mechanical properties of the nucleus influence different cellular and nuclear functions and have relevant implications for several human diseases. The nucleus protects genetic information while acting as a mechano-sensory hub in response to internal and external forces. Cells have evolved mechano-transduction signaling to respond to physical cellular and nuclear perturbations and adopted a multitude of molecular pathways to maintain nuclear shape stability and prevent morphological abnormalities of the nucleus. Here we describe those key biological processes that control nuclear mechanics and discuss emerging perspectives on the mechanobiology of the nucleus as a diagnostic tool and clinical target.
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Affiliation(s)
- Giulia Bastianello
- IFOM, The FIRC Institute of Molecular Oncology, Milan 20139, Italy; Oncology and Haemato-Oncology Department, University of Milan, Milan 20122, Italy.
| | - Marco Foiani
- IFOM, The FIRC Institute of Molecular Oncology, Milan 20139, Italy; Oncology and Haemato-Oncology Department, University of Milan, Milan 20122, Italy.
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14
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Chiu K, Berrada Y, Eskndir N, Song D, Fong C, Naughton S, Chen T, Moy S, Gyurmey S, James L, Ezeiruaku C, Capistran C, Lowey D, Diwanji V, Peterson S, Parakh H, Burgess AR, Probert C, Zhu A, Anderson B, Levi N, Gerlitz G, Packard MC, Dorfman KA, Bahiru MS, Stephens AD. CTCF is essential for proper mitotic spindle structure and anaphase segregation. Chromosoma 2023:10.1007/s00412-023-00810-w. [PMID: 37728741 DOI: 10.1007/s00412-023-00810-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 08/11/2023] [Accepted: 09/08/2023] [Indexed: 09/21/2023]
Abstract
Mitosis is an essential process in which the duplicated genome is segregated equally into two daughter cells. CTCF has been reported to be present in mitosis and has a role in localizing CENP-E, but its importance for mitotic fidelity remains to be determined. To evaluate the importance of CTCF in mitosis, we tracked mitotic behaviors in wild-type and two different CTCF CRISPR-based genetic knockdowns. We find that knockdown of CTCF results in prolonged mitoses and failed anaphase segregation via time-lapse imaging of SiR-DNA. CTCF knockdown did not alter cell cycling or the mitotic checkpoint, which was activated upon nocodazole treatment. Immunofluorescence imaging of the mitotic spindle in CTCF knockdowns revealed disorganization via tri/tetrapolar spindles and chromosomes behind the spindle pole. Imaging of interphase nuclei showed that nuclear size increased drastically, consistent with failure to divide the duplicated genome in anaphase. Long-term inhibition of CNEP-E via GSK923295 recapitulates CTCF knockdown abnormal mitotic spindles with polar chromosomes and increased nuclear sizes. Population measurements of nuclear shape in CTCF knockdowns do not display decreased circularity or increased nuclear blebbing relative to wild-type. However, failed mitoses do display abnormal nuclear morphologies relative to successful mitoses, suggesting that population images do not capture individual behaviors. Thus, CTCF is important for both proper metaphase organization and anaphase segregation which impacts the size and shape of the interphase nucleus likely through its known role in recruiting CENP-E.
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Affiliation(s)
- Katherine Chiu
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Yasmin Berrada
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Nebiyat Eskndir
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Dasol Song
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Claire Fong
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Sarah Naughton
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Tina Chen
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Savanna Moy
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Sarah Gyurmey
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Liam James
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Chimere Ezeiruaku
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Caroline Capistran
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Daniel Lowey
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Vedang Diwanji
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Samantha Peterson
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Harshini Parakh
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Ayanna R Burgess
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Cassandra Probert
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Annie Zhu
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Bryn Anderson
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Nehora Levi
- Biology Department of Molecular Biology, Faculty of Life Sciences, Ariel University, 40700, Ariel, Israel
| | - Gabi Gerlitz
- Biology Department of Molecular Biology, Faculty of Life Sciences, Ariel University, 40700, Ariel, Israel
| | - Mary C Packard
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Katherine A Dorfman
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Michael Seifu Bahiru
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, 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.
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15
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Tang W, Chen X, Wang X, Zhu M, Shan G, Wang T, Dou W, Wang J, Law J, Gong Z, Hopyan S, Huang X, Sun Y. Indentation induces instantaneous nuclear stiffening and unfolding of nuclear envelope wrinkles. Proc Natl Acad Sci U S A 2023; 120:e2307356120. [PMID: 37639585 PMCID: PMC10483616 DOI: 10.1073/pnas.2307356120] [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: 05/03/2023] [Accepted: 07/21/2023] [Indexed: 08/31/2023] Open
Abstract
The nuclear envelope (NE) separates genomic DNA from the cytoplasm and regulates transport between the cytosol and the nucleus in eukaryotes. Nuclear stiffening enables the cell nucleus to protect itself from extensive deformation, loss of NE integrity, and genome instability. It is known that the reorganization of actin, lamin, and chromatin can contribute to nuclear stiffening. In this work, we show that structural alteration of NE also contributes to instantaneous nuclear stiffening under indentation. In situ mechanical characterization of cell nuclei in intact cells shows that nuclear stiffening and unfolding of NE wrinkles occur simultaneously at the indentation site. A positive correlation between the initial state of NE wrinkles, the unfolding of NE wrinkles, and the stiffening ratio (stiffness fold-change) is found. Additionally, NE wrinkles unfold throughout the nucleus outside the indentation site. Finite element simulation, which involves the purely passive process of structural unfolding, shows that unfolding of NE wrinkles alone can lead to an increase in nuclear stiffness and a reduction in stress and strain levels. Together, these results provide a perspective on how cell nucleus adapts to mechanical stimuli through structural alteration of the NE.
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Affiliation(s)
- Wentian Tang
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ONM5S 3G8, Canada
| | - Xin Chen
- Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, ONM5G 1X8, Canada
- Program in Developmental and Stem Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, ONM5G 1X8, Canada
| | - Xian Wang
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ONM5S 3G8, Canada
- Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, ONM5G 1X8, Canada
| | - Min Zhu
- Program in Developmental and Stem Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, ONM5G 1X8, Canada
| | - Guanqiao Shan
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ONM5S 3G8, Canada
| | - Tiancong Wang
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ONM5S 3G8, Canada
| | - Wenkun Dou
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ONM5S 3G8, Canada
| | - Jintian Wang
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ONM5S 3G8, Canada
| | - Junhui Law
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ONM5S 3G8, Canada
| | - Zheyuan Gong
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ONM5S 3G8, Canada
| | - Sevan Hopyan
- Program in Developmental and Stem Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, ONM5G 1X8, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ONM5S 1A8, Canada
- Division of Orthopaedic Surgery, The Hospital for Sick Children, Toronto, ONM5G 1X8, Canada
| | - Xi Huang
- Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, ONM5G 1X8, Canada
- Program in Developmental and Stem Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, ONM5G 1X8, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ONM5S 1A8, Canada
| | - Yu Sun
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ONM5S 3G8, Canada
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, ONM5S 3G4, Canada
- Department of Computer Science, University of Toronto, Toronto, ONM5S 3G4, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, ONM5S 3G9, Canada
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16
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Dobbs OG, Wilson RHC, Newling K, Ainscough JFX, Coverley D. Epigenetic instability caused by absence of CIZ1 drives transformation during quiescence cycles. BMC Biol 2023; 21:175. [PMID: 37580709 PMCID: PMC10426085 DOI: 10.1186/s12915-023-01671-6] [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: 12/12/2022] [Accepted: 07/31/2023] [Indexed: 08/16/2023] Open
Abstract
BACKGROUND Cip1-interacting zinc finger protein 1 (CIZ1) forms RNA-dependent protein assemblies that stabilise epigenetic state, notable at the inactive X chromosome in females. CIZ1 has been linked with a range of human cancers and in mice genetic deletion of CIZ1 manifests as hyperproliferative lymphoid lineages in females. This suggests that its role in maintenance of epigenetic stability is linked with disease. RESULTS Here, we show that male and female CIZ1-null primary murine fibroblasts have reduced H4K20me1 and that this compromises nuclear condensation on entry to quiescence. Global transcriptional repression remains intact in condensation-deficient CIZ1-null cells; however, a subset of genes linked with chromatin condensation and homology-directed DNA repair are perturbed. Failure to condense is phenotypically mimicked by manipulation of the H4K20me1 methyltransferase, SET8, in WT cells and partially reverted in CIZ1-null cells upon re-expression of CIZ1. Crucially, during exit from quiescence, nuclear decondensation remains active, so that repeated entry and exit cycles give rise to expanded nuclei susceptible to mechanical stress, DNA damage checkpoint activation, and downstream emergence of transformed proliferative colonies. CONCLUSIONS Our results demonstrate a role for CIZ1 in chromatin condensation on entry to quiescence and explore the consequences of this defect in CIZ1-null cells. Together, the data show that CIZ1's protection of the epigenome guards against genome instability during quiescence cycles. This identifies loss of CIZ1 as a potentially devastating vulnerability in cells that undergo cycles of quiescence entry and exit.
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Affiliation(s)
- Olivia G Dobbs
- Department of Biology, University of York, York, YO10 5DD, UK.
- York Biomedical Research Institute, University of York, York, UK.
| | - Rosemary H C Wilson
- Department of Biology, University of York, York, YO10 5DD, UK
- Exact Sciences Innovation, The Sherard Building, Oxford Science Park, Edmund Halley Rd, Oxford, OX4 4DQ, UK
| | - Katherine Newling
- Department of Biology, University of York, York, YO10 5DD, UK
- Genomics and Bioinformatics Laboratory, Bioscience Technology Facility, University of York, York, YO10 5DD, UK
| | | | - Dawn Coverley
- Department of Biology, University of York, York, YO10 5DD, UK
- York Biomedical Research Institute, University of York, York, UK
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17
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Fan Q, Li XM, Zhai C, Li B, Li ST, Dong MQ. Somatic nuclear blebbing in Caenorhabditis elegans is not a feature of organismal aging but a potential indicator of germline proliferation in early adulthood. G3 (BETHESDA, MD.) 2023; 13:jkad029. [PMID: 36735812 PMCID: PMC10085788 DOI: 10.1093/g3journal/jkad029] [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: 09/13/2022] [Revised: 01/26/2023] [Accepted: 01/27/2023] [Indexed: 02/05/2023]
Abstract
Abnormal nuclear morphology is suggested to be a hallmark of aging and one such abnormality is nuclear blebbing. However, little is known about whether and how nuclear blebbing participates in animal aging, and what regulates it. In this study, we show that the frequency of nuclear blebbing in the hypodermis increases during aging in wild-type C. elegans. These nuclear blebs are enveloped by the nuclear lamina, the inner and the outer nuclear membrane, and 42% of them contain chromatin. Although nuclear blebbing could lead to DNA loss if chromatin-containing blebs detach and fuse with lysosomes, we find by time-lapse imaging that nuclear blebs rarely detach, and the estimated lifetime of a nuclear bleb is 772 h or 32 days. The amount of DNA lost through nuclear blebbing is estimated to be about 0.1% of the total DNA loss by adult Day 11. Furthermore, the frequency of nuclear blebbing does not correlate with the rate of aging in C. elegans. Old age does not necessarily induce nuclear blebbing, neither does starvation, heat stress, or oxidative stress. Intriguingly, we find that proliferation of germ cells promotes nuclear blebbing.
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Affiliation(s)
- Qiang Fan
- Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, China
- National Institute of Biological Sciences (NIBS), Beijing 102206, China
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 102206, China
| | - Xue-Mei Li
- National Institute of Biological Sciences (NIBS), Beijing 102206, China
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 102206, China
| | - Chao Zhai
- National Institute of Biological Sciences (NIBS), Beijing 102206, China
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 102206, China
| | - Bin Li
- National Institute of Biological Sciences (NIBS), Beijing 102206, China
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 102206, China
| | - Shang-Tong Li
- National Institute of Biological Sciences (NIBS), Beijing 102206, China
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 102206, China
| | - Meng-Qiu Dong
- Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, China
- National Institute of Biological Sciences (NIBS), Beijing 102206, China
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 102206, China
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18
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Zhao B, Lv Y. A biomechanical view of epigenetic tumor regulation. J Biol Phys 2023:10.1007/s10867-023-09633-3. [PMID: 37004697 PMCID: PMC10397176 DOI: 10.1007/s10867-023-09633-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [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.
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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.
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19
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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: 4] [Impact Index Per Article: 4.0] [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.
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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.
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20
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Tuning between Nuclear Organization and Functionality in Health and Disease. Cells 2023; 12:cells12050706. [PMID: 36899842 PMCID: PMC10000962 DOI: 10.3390/cells12050706] [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: 12/16/2022] [Revised: 02/08/2023] [Accepted: 02/20/2023] [Indexed: 02/25/2023] Open
Abstract
The organization of eukaryotic genome in the nucleus, a double-membraned organelle separated from the cytoplasm, is highly complex and dynamic. The functional architecture of the nucleus is confined by the layers of internal and cytoplasmic elements, including chromatin organization, nuclear envelope associated proteome and transport, nuclear-cytoskeletal contacts, and the mechano-regulatory signaling cascades. The size and morphology of the nucleus could impose a significant impact on nuclear mechanics, chromatin organization, gene expression, cell functionality and disease development. The maintenance of nuclear organization during genetic or physical perturbation is crucial for the viability and lifespan of the cell. Abnormal nuclear envelope morphologies, such as invagination and blebbing, have functional implications in several human disorders, including cancer, accelerated aging, thyroid disorders, and different types of neuro-muscular diseases. Despite the evident interplay between nuclear structure and nuclear function, our knowledge about the underlying molecular mechanisms for regulation of nuclear morphology and cell functionality during health and illness is rather poor. This review highlights the essential nuclear, cellular, and extracellular components that govern the organization of nuclei and functional consequences associated with nuclear morphometric aberrations. Finally, we discuss the recent developments with diagnostic and therapeutic implications targeting nuclear morphology in health and disease.
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21
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Vadrot N, Ader F, Moulin M, Merlant M, Chapon F, Gandjbakhch E, Labombarda F, Maragnes P, Réant P, Rooryck C, Probst V, Donal E, Richard P, Ferreiro A, Buendia B. Abnormal Cellular Phenotypes Induced by Three TMPO/LAP2 Variants Identified in Men with Cardiomyopathies. Cells 2023; 12:337. [PMID: 36672271 PMCID: PMC9857342 DOI: 10.3390/cells12020337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/09/2023] [Accepted: 01/11/2023] [Indexed: 01/18/2023] Open
Abstract
A single missense variant of the TMPO/LAP2α gene, encoding LAP2 proteins, has been associated with cardiomyopathy in two brothers. To further evaluate its role in cardiac muscle, we included TMPO in our cardiomyopathy diagnostic gene panel. A screening of ~5000 patients revealed three novel rare TMPO heterozygous variants in six males diagnosed with hypertrophic or dilated cardiomypathy. We identified in different cellular models that (1) the frameshift variant LAP2α p.(Gly395Glufs*11) induced haploinsufficiency, impeding cell proliferation and/or producing a truncated protein mislocalized in the cytoplasm; (2) the C-ter missense variant LAP2α p.(Ala240Thr) led to a reduced proximity events between LAP2α and the nucleosome binding protein HMGN5; and (3) the LEM-domain missense variant p.(Leu124Phe) decreased both associations of LAP2α/β with the chromatin-associated protein BAF and inhibition of the E2F1 transcription factor activity which is known to be dependent on Rb, partner of LAP2α. Additionally, the LAP2α expression was lower in the left ventricles of male mice compared to females. In conclusion, our study reveals distinct altered properties of LAP2 induced by these TMPO/LAP2 variants, leading to altered cell proliferation, chromatin structure or gene expression-regulation pathways, and suggests a potential sex-dependent role of LAP2 in myocardial function and disease.
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Affiliation(s)
- Nathalie Vadrot
- Basic and Translational Myology Laboratory, Université Paris Cité, BFA, UMR 8251, CNRS, F-75013 Paris, France
| | - Flavie Ader
- APHP—Sorbonne Université, Unité Fonctionnelle de Cardiogénétique et Myogénétique Moléculaire, Service de Biochimie Métabolique, HU Pitié Salpêtrière—Charles Foix, F-75013 Paris, France
- INSERM, UMR_S 1166, Sorbonne Université, F-75005 Paris, France
- Faculté de Pharmacie Paris Descartes, Département 3, Université Paris Cité, F-75006 Paris, France
| | - Maryline Moulin
- Basic and Translational Myology Laboratory, Université Paris Cité, BFA, UMR 8251, CNRS, F-75013 Paris, France
| | - Marie Merlant
- Basic and Translational Myology Laboratory, Université Paris Cité, BFA, UMR 8251, CNRS, F-75013 Paris, France
| | | | - Estelle Gandjbakhch
- INSERM, UMR_S 1166, Sorbonne Université, F-75005 Paris, France
- Département de cardiologie, APHP—Sorbonne Université, HU Pitié Salpêtrière- Charles Foix, F-75610 Paris, France
| | - Fabien Labombarda
- Service de Cardiologie, CHU de Caen, Université de Caen Normandie, F-14000 Caen, France
| | - Pascale Maragnes
- Cardiologie pédiatrique, Service de pédiatrie, CHU de Caen, F-14000 Caen, France
| | - Patricia Réant
- Service de Cardiologie, Hôpital Haut Lévêque, CHU de Bordeaux, INSERM 1045, Université de Bordeaux, F-33000 Bordeaux, France
| | - Caroline Rooryck
- Service de Génétique Médicale, CHU Bordeaux, F-33000 Bordeaux, France
| | - Vincent Probst
- Centre de référence des maladies rythmiques cardiaques, CHU de Nantes, F-44000 Nantes, France
| | - Erwan Donal
- Centre Cardio-Pneumologique, CHU de Rennes Hôpital de Pontchaillou, F-35000 Rennes, France
| | - Pascale Richard
- APHP—Sorbonne Université, Unité Fonctionnelle de Cardiogénétique et Myogénétique Moléculaire, Service de Biochimie Métabolique, HU Pitié Salpêtrière—Charles Foix, F-75013 Paris, France
- INSERM, UMR_S 1166, Sorbonne Université, F-75005 Paris, France
| | - Ana Ferreiro
- Basic and Translational Myology Laboratory, Université Paris Cité, BFA, UMR 8251, CNRS, F-75013 Paris, France
- APHP, Centre de référence des Maladies Neuromusculaires, Institut de Myologie, Neuromyology Department, CHU Pitié Salpêtrière—Charles Foix, F-75013 Paris, France
| | - Brigitte Buendia
- Basic and Translational Myology Laboratory, Université Paris Cité, BFA, UMR 8251, CNRS, F-75013 Paris, France
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22
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Chiu K, Berrada Y, Eskndir N, Song D, Fong C, Naughton S, Chen T, Moy S, Gyurmey S, James L, Ezeiruaku C, Capistran C, Lowey D, Diwanji V, Peterson S, Parakh H, Burgess AR, Probert C, Zhu A, Anderson B, Levi N, Gerlitz G, Packard MC, Dorfman KA, Bahiru MS, Stephens AD. CTCF is essential for proper mitotic spindle structure and anaphase segregation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.09.523293. [PMID: 36712070 PMCID: PMC9881978 DOI: 10.1101/2023.01.09.523293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Mitosis is an essential process in which the duplicated genome is segregated equally into two daughter cells. CTCF has been reported to be present in mitosis but its importance for mitotic fidelity remains to be determined. To evaluate the importance of CTCF in mitosis, we tracked mitotic behaviors in wild type and two different CTCF CRISPR-based genetic knockdowns. We find that knockdown of CTCF results in prolonged mitoses and failed anaphase segregation via time lapse imaging of SiR-DNA. CTCF knockdown did not alter cell cycling or the mitotic checkpoint, which was activated upon nocodazole treatment. Immunofluorescence imaging of the mitotic spindle in CTCF knockdowns revealed disorganization via tri/tetrapolar spindles and chromosomes behind the spindle pole. Imaging of interphase nuclei showed that nuclear size increased drastically, consistent with failure to divide the duplicated genome in anaphase. Population measurements of nuclear shape in CTCF knockdowns do not display decreased circularity or increased nuclear blebbing relative to wild type. However, failed mitoses do display abnormal nuclear morphologies relative to successful mitoses, suggesting population images do not capture individual behaviors. Thus, CTCF is important for both proper metaphase organization and anaphase segregation which impacts the size and shape of the interphase nucleus.
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Affiliation(s)
- Katherine Chiu
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Yasmin Berrada
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Nebiyat Eskndir
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Dasol Song
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Claire Fong
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Sarah Naughton
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Tina Chen
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Savanna Moy
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Sarah Gyurmey
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Liam James
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Chimere Ezeiruaku
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Caroline Capistran
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Daniel Lowey
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Vedang Diwanji
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Samantha Peterson
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Harshini Parakh
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Ayanna R. Burgess
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Cassandra Probert
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Annie Zhu
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Bryn Anderson
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Nehora Levi
- Biology Department of Molecular Biology, Faculty of Life Sciences, Ariel University, Ariel 40700, Israel
| | - Gabi Gerlitz
- Biology Department of Molecular Biology, Faculty of Life Sciences, Ariel University, Ariel 40700, Israel
| | - Mary C. Packard
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, 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
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23
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Li W, An N, Wang M, Liu X, Mei Z. Downregulation of AT-rich interaction domain 2 underlies natural killer cell dysfunction in oral squamous cell carcinoma. Immunol Cell Biol 2023; 101:78-90. [PMID: 36269235 DOI: 10.1111/imcb.12602] [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: 05/21/2022] [Revised: 09/15/2022] [Accepted: 10/20/2022] [Indexed: 11/06/2022]
Abstract
The immune system plays a significant role in controlling oral squamous cell carcinoma (OSCC) initiation and progression. Natural killer (NK) cells actively participate in antitumor immunity but become dysfunctional or exhausted in the tumor microenvironment. To explore the mechanisms of NK cell dysfunction in OSCC, we characterized the expression and function of AT-rich interaction domain 2 (ARID2) in NK cells in a murine OSCC model. ARID2 was downregulated in tongue NK cells compared with splenic NK cells. Notably, ARID2 was significantly decreased in NK cells with an exhausted phenotype and weakened antitumor function. ARID2 knockdown resulted in the upregulation of programmed cell death protein 1 (PD-1) and downregulation of interferon-gamma (IFN-γ), tumor necrosis factor (TNF), granzyme B and perforin in NK cells. As a result, ARID2 knockdown impaired NK cell cytotoxicity. Besides, ARID2 overexpression suppressed the expression of PD-1 and lymphocyte-activation gene 3, and promoted the expression of IFN-γ, TNF, granzyme B and perforin in NK cells which were adoptively transferred into OSCC-bearing mice. Taken together, our study implies that the OSCC microenvironment triggers ARID2 downregulation in intratumoral NK cells. In turn, ARID2 downregulation results in PD-1 upregulation on NK cells and subsequently impairs NK cell cytotoxicity. Therefore, we uncovered a novel mechanism of NK cell dysfunction in OSCC.
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Affiliation(s)
- Wei Li
- Department of Head and Neck Surgery, Hubei Cancer Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ning An
- Department of Head and Neck Surgery, Hubei Cancer Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Mingwei Wang
- Department of Pathology, Hubei Cancer Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiguo Liu
- Department of Head and Neck Surgery, Hubei Cancer Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhidan Mei
- Department of Head and Neck Surgery, Hubei Cancer Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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24
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Carollo PS, Barra V. Chromatin epigenetics and nuclear lamina keep the nucleus in shape: Examples from natural and accelerated aging. Biol Cell 2023; 115:e2200023. [PMID: 36117150 DOI: 10.1111/boc.202200023] [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: 04/01/2022] [Revised: 09/11/2022] [Accepted: 09/12/2022] [Indexed: 01/07/2023]
Abstract
As the repository of genetic information, the cell nucleus must protect DNA integrity from mechanical stresses. The nuclear lamina, which resides within the nuclear envelope (NE), is made up of lamins, intermediate filaments bound to DNA. The nuclear lamina provides the nucleus with the ability to deal with inward as well as outward mechanical stimuli. Chromatin, in turn, through its degrees of compaction, shares this role with the nuclear lamina, thus, ensuring the plasticity of the nucleus. Perturbation of chromatin condensation or the nuclear lamina has been linked to a plethora of biological conditions, that range from cancer and genetic diseases (laminopathies) to aging, both natural and accelerated, such as the case of Hutchinson-Gilford Progeria Syndrome (HGPS). From the experimental results accumulated so far on the topic, a direct link between variations of the epigenetic pattern and nuclear lamina structure would be suggested, however, it has never been clarified thoroughly. This relationship, instead, has a downstream important implication on nucleus shape, genome preservation, force sensing, and, ultimately, aging-related disease onset. With this review, we aim to collect recent studies on the importance of both nuclear lamina components and chromatin status in nuclear mechanics. We also aim to bring to light evidence of the link between DNA methylation and nuclear lamina in natural and accelerated aging.
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Affiliation(s)
- Pietro Salvatore Carollo
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies, University of Palermo, Palermo, Italy
| | - Viviana Barra
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies, University of Palermo, Palermo, Italy
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25
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Gridina M, Fishman V. Multilevel view on chromatin architecture alterations in cancer. Front Genet 2022; 13:1059617. [PMID: 36468037 PMCID: PMC9715599 DOI: 10.3389/fgene.2022.1059617] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Accepted: 10/31/2022] [Indexed: 12/25/2023] Open
Abstract
Chromosomes inside the nucleus are not located in the form of linear molecules. Instead, there is a complex multilevel genome folding that includes nucleosomes packaging, formation of chromatin loops, domains, compartments, and finally, chromosomal territories. Proper spatial organization play an essential role for the correct functioning of the genome, and is therefore dynamically changed during development or disease. Here we discuss how the organization of the cancer cell genome differs from the healthy genome at various levels. A better understanding of how malignization affects genome organization and long-range gene regulation will help to reveal the molecular mechanisms underlying cancer development and evolution.
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Affiliation(s)
- Maria Gridina
- The Federal Research Center Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
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26
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Danielsson BE, Tieu KV, Spagnol ST, Vu KK, Cabe JI, Raisch TB, Dahl KN, Conway DE. Chromatin condensation regulates endothelial cell adaptation to shear stress. Mol Biol Cell 2022; 33:ar101. [PMID: 35895088 DOI: 10.1091/mbc.e22-02-0064] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Vascular endothelial cells (ECs) have been shown to be mechanoresponsive to the forces of blood flow, including fluid shear stress (FSS), the frictional force of blood on the vessel wall. Recent reports have shown that FSS induces epigenetic changes in chromatin. Epigenetic changes, such as methylation and acetylation of histones, not only affect gene expression but also affect chromatin condensation, which can alter nuclear stiffness. Thus, we hypothesized that changes in chromatin condensation may be an important component for how ECs adapt to FSS. Using both in vitro and in vivo models of EC adaptation to FSS, we observed an increase in histone acetylation and a decrease in histone methylation in ECs adapted to flow as compared with static. Using small molecule drugs, as well as vascular endothelial growth factor, to change chromatin condensation, we show that decreasing chromatin condensation enables cells to more quickly align to FSS, whereas increasing chromatin condensation inhibited alignment. Additionally, we show data that changes in chromatin condensation can also prevent or increase DNA damage, as measured by phosphorylation of γH2AX. Taken together, these results indicate that chromatin condensation, and potentially by extension nuclear stiffness, is an important aspect of EC adaptation to FSS.
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Affiliation(s)
- Brooke E Danielsson
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia 23284
| | - Katie V Tieu
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia 23284
| | - Stephen T Spagnol
- Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Kira K Vu
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia 23284
| | - Jolene I Cabe
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia 23284
| | - Tristan B Raisch
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia 23284
| | - Kris Noel Dahl
- Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213.,Forensics Department, Thornton Tomasetti, New York City, NY 10271
| | - Daniel E Conway
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia 23284.,Department of Biomedical Engineering, The Ohio State University, Columbus, OH 43210.,Center for Cancer Engineering, and Arthur G. James Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210
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27
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Joshi R, Han SB, Cho WK, Kim DH. The role of cellular traction forces in deciphering nuclear mechanics. Biomater Res 2022; 26:43. [PMID: 36076274 PMCID: PMC9461125 DOI: 10.1186/s40824-022-00289-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 08/28/2022] [Indexed: 11/10/2022] Open
Abstract
Cellular forces exerted on the extracellular matrix (ECM) during adhesion and migration under physiological and pathological conditions regulate not only the overall cell morphology but also nuclear deformation. Nuclear deformation can alter gene expression, integrity of the nuclear envelope, nucleus-cytoskeletal connection, chromatin architecture, and, in some cases, DNA damage responses. Although nuclear deformation is caused by the transfer of forces from the ECM to the nucleus, the role of intracellular organelles in force transfer remains unclear and a challenging area of study. To elucidate nuclear mechanics, various factors such as appropriate biomaterial properties, processing route, cellular force measurement technique, and micromanipulation of nuclear forces must be understood. In the initial phase of this review, we focused on various engineered biomaterials (natural and synthetic extracellular matrices) and their manufacturing routes along with the properties required to mimic the tumor microenvironment. Furthermore, we discussed the principle of tools used to measure the cellular traction force generated during cell adhesion and migration, followed by recently developed techniques to gauge nuclear mechanics. In the last phase of this review, we outlined the principle of traction force microscopy (TFM), challenges in the remodeling of traction forces, microbead displacement tracking algorithm, data transformation from bead movement, and extension of 2-dimensional TFM to multiscale TFM.
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Affiliation(s)
- Rakesh Joshi
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, South Korea
| | - Seong-Beom Han
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, South Korea
| | - Won-Ki Cho
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea
| | - Dong-Hwee Kim
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, South Korea. .,Department of Integrative Energy Engineering, College of Engineering, Korea University, Seoul, South Korea.
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28
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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: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [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.
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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
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29
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Kalukula Y, Stephens AD, Lammerding J, Gabriele S. Mechanics and functional consequences of nuclear deformations. Nat Rev Mol Cell Biol 2022; 23:583-602. [PMID: 35513718 PMCID: PMC9902167 DOI: 10.1038/s41580-022-00480-z] [Citation(s) in RCA: 93] [Impact Index Per Article: 46.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/29/2022] [Indexed: 02/08/2023]
Abstract
As the home of cellular genetic information, the nucleus has a critical role in determining cell fate and function in response to various signals and stimuli. In addition to biochemical inputs, the nucleus is constantly exposed to intrinsic and extrinsic mechanical forces that trigger dynamic changes in nuclear structure and morphology. Emerging data suggest that the physical deformation of the nucleus modulates many cellular and nuclear functions. These functions have long been considered to be downstream of cytoplasmic signalling pathways and dictated by gene expression. In this Review, we discuss an emerging perspective on the mechanoregulation of the nucleus that considers the physical connections from chromatin to nuclear lamina and cytoskeletal filaments as a single mechanical unit. We describe key mechanisms of nuclear deformations in time and space and provide a critical review of the structural and functional adaptive responses of the nucleus to deformations. We then consider the contribution of nuclear deformations to the regulation of important cellular functions, including muscle contraction, cell migration and human disease pathogenesis. Collectively, these emerging insights shed new light on the dynamics of nuclear deformations and their roles in cellular mechanobiology.
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Affiliation(s)
- Yohalie Kalukula
- University of Mons, Soft Matter and Biomaterials group, Interfaces and Complex Fluids Laboratory, Research Institute for Biosciences, CIRMAP, Place du Parc, 20 B-7000 Mons, Belgium
| | - Andrew D. Stephens
- Biology Department, University of Massachusetts Amherst, Amherst, MA, USA
| | - Jan Lammerding
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA,Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Sylvain Gabriele
- University of Mons, Soft Matter and Biomaterials group, Interfaces and Complex Fluids Laboratory, Research Institute for Biosciences, CIRMAP, Place du Parc, 20 B-7000 Mons, Belgium
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30
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Kim JM. Molecular Link between DNA Damage Response and Microtubule Dynamics. Int J Mol Sci 2022; 23:ijms23136986. [PMID: 35805981 PMCID: PMC9266319 DOI: 10.3390/ijms23136986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/20/2022] [Accepted: 06/21/2022] [Indexed: 11/16/2022] Open
Abstract
Microtubules are major components of the cytoskeleton that play important roles in cellular processes such as intracellular transport and cell division. In recent years, it has become evident that microtubule networks play a role in genome maintenance during interphase. In this review, we highlight recent advances in understanding the role of microtubule dynamics in DNA damage response and repair. We first describe how DNA damage checkpoints regulate microtubule organization and stability. We then highlight how microtubule networks are involved in the nuclear remodeling following DNA damage, which leads to changes in chromosome organization. Lastly, we discuss how microtubule dynamics participate in the mobility of damaged DNA and promote consequent DNA repair. Together, the literature indicates the importance of microtubule dynamics in genome organization and stability during interphase.
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Affiliation(s)
- Jung Min Kim
- Department of Pharmacology, Chonnam National University Medical School, Gwangju 58128, Korea
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31
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Lee DSW, Strom AR, Brangwynne CP. The mechanobiology of nuclear phase separation. APL Bioeng 2022; 6:021503. [PMID: 35540725 PMCID: PMC9054271 DOI: 10.1063/5.0083286] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 04/19/2022] [Indexed: 02/06/2023] Open
Abstract
The cell nucleus can be thought of as a complex, dynamic, living material, which functions to organize and protect the genome and coordinate gene expression. These functions are achieved via intricate mechanical and biochemical interactions among its myriad components, including the nuclear lamina, nuclear bodies, and the chromatin itself. While the biophysical organization of the nuclear lamina and chromatin have been thoroughly studied, the concept that liquid–liquid phase separation and related phase transitions play a role in establishing nuclear structure has emerged only recently. Phase transitions are likely to be intimately coupled to the mechanobiology of structural elements in the nucleus, but their interplay with one another is still not understood. Here, we review recent developments on the role of phase separation and mechanics in nuclear organization and discuss the functional implications in cell physiology and disease states.
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Affiliation(s)
- Daniel S. W. Lee
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544, USA
| | - Amy R. Strom
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Clifford P. Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA
- Princeton Institute for the Science and Technology of Materials, Princeton University, Princeton, New Jersey 08544, USA
- Howard Hughes Medical Institute, Princeton University, Princeton, New Jersey 08544, USA
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32
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Atanasova KR, Chakraborty S, Ratnayake R, Khare KD, Luesch H, Lele TP. An epigenetic small molecule screen to target abnormal nuclear morphology in human cells. Mol Biol Cell 2022; 33:ar45. [PMID: 35323046 PMCID: PMC9265153 DOI: 10.1091/mbc.e21-10-0528] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Irregular nuclear shapes are a hallmark of human cancers. Recent studies suggest that alterations to chromatin regulators may cause irregular nuclear morphologies. Here we screened an epigenetic small molecule library consisting of 145 compounds against chromatin regulators, for their ability to revert abnormal nuclear shapes that were induced by gene knockdown in non-cancerous MCF10A human mammary breast epithelial cells. We leveraged a previously validated quantitative Fourier approach to quantify the elliptical Fourier coefficient (EFC ratio) as a measure of nuclear irregularities, which allowed us to perform rigorous statistical analyses of screening data. Top hit compounds fell into three major mode of action categories, targeting three separate epigenetic modulation routes: 1) Histone deacetylase (HDAC) inhibitors; 2) Bromodomain and extra-terminal domain (BET) protein inhibitors; and 3) Methyl-transferase inhibitors. Some of the top hit compounds were also efficacious in reverting nuclear irregularities in MDA-MB-231 triple negative breast cancer cells and in PANC-1 pancreatic cancer cells in a cell type dependent manner. Regularization of nuclear shapes was compound-specific, cell-type specific, and dependent on the specific molecular perturbation that induced nuclear irregularities. Our approach of targeting nuclear abnormalities may be potentially useful in screening new types of cancer therapies targeted toward chromatin structure.
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Affiliation(s)
- Kalina R Atanasova
- Department of Medicinal Chemistry and Center for Natural Products, Drug Discovery and Development (CNPD3), University of Florida, Gainesville FL 32610, USA
| | - Saptarshi Chakraborty
- Department of Biostatistics, State University of New York at Buffalo, Buffalo NY 14214, USA
| | - Ranjala Ratnayake
- Department of Medicinal Chemistry and Center for Natural Products, Drug Discovery and Development (CNPD3), University of Florida, Gainesville FL 32610, USA
| | - Kshitij D Khare
- Department of Statistics, University of Florida, Gainesville FL 32611, USA
| | - Hendrik Luesch
- Department of Medicinal Chemistry and Center for Natural Products, Drug Discovery and Development (CNPD3), University of Florida, Gainesville FL 32610, USA
| | - Tanmay P Lele
- Department of Biomedical Engineering, Department of Chemical Engineering, and Department of Translational Medical Sciences, Texas A&M University, College Station TX 77843, USA
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33
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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.
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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
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34
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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.
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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
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36
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Mammel AE, Huang HZ, Gunn AL, Choo E, Hatch EM. Chromosome length and gene density contribute to micronuclear membrane stability. Life Sci Alliance 2022; 5:e202101210. [PMID: 34789512 PMCID: PMC8605325 DOI: 10.26508/lsa.202101210] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 11/01/2021] [Accepted: 11/03/2021] [Indexed: 11/24/2022] Open
Abstract
Micronuclei are derived from missegregated chromosomes and frequently lose membrane integrity, leading to DNA damage, innate immune activation, and metastatic signaling. Here, we demonstrate that two characteristics of the trapped chromosome, length and gene density, are key contributors to micronuclei membrane stability and determine the timing of micronucleus rupture. We demonstrate that these results are not due to chromosome-specific differences in spindle position or initial protein recruitment during post-mitotic nuclear envelope assembly. Micronucleus size strongly correlates with lamin B1 levels and nuclear pore density in intact micronuclei, but, unexpectedly, lamin B1 levels do not completely predict nuclear lamina organization or membrane stability. Instead, small gene-dense micronuclei have decreased nuclear lamina gaps compared to large micronuclei, despite very low levels of lamin B1. Our data strongly suggest that nuclear envelope composition defects previously correlated with membrane rupture only partly explain membrane stability in micronuclei. We propose that an unknown factor linked to gene density has a separate function that inhibits the appearance of nuclear lamina gaps and delays membrane rupture until late in the cell cycle.
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Affiliation(s)
- Anna E Mammel
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Heather Z Huang
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Amanda L Gunn
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Emma Choo
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Emily M Hatch
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
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37
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Singh I, Lele TP. Nuclear Morphological Abnormalities in Cancer: A Search for Unifying Mechanisms. Results Probl Cell Differ 2022; 70:443-467. [PMID: 36348118 PMCID: PMC9722227 DOI: 10.1007/978-3-031-06573-6_16] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Irregularities in nuclear shape and/or alterations to nuclear size are a hallmark of malignancy in a broad range of cancer types. Though these abnormalities are commonly used for diagnostic purposes and are often used to assess cancer progression in the clinic, the mechanisms through which they occur are not well understood. Nuclear size alterations in cancer could potentially arise from aneuploidy, changes in osmotic coupling with the cytoplasm, and perturbations to nucleocytoplasmic transport. Nuclear shape changes may occur due to alterations to cell-generated mechanical stresses and/or alterations to nuclear structural components, which balance those stresses, such as the nuclear lamina and chromatin. A better understanding of the mechanisms underlying abnormal nuclear morphology and size may allow the development of new therapeutics to target nuclear aberrations in cancer.
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Affiliation(s)
- Ishita Singh
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, USA
| | - Tanmay P. Lele
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, USA,Department of Chemical Engineering, University of Florida, Gainesville, FL, USA,Department of Translational Medical Sciences, Texas A&M University, Houston, TX, USA
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38
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Goelzer M, Goelzer J, Ferguson ML, Neu CP, Uzer G. Nuclear envelope mechanobiology: linking the nuclear structure and function. Nucleus 2021; 12:90-114. [PMID: 34455929 PMCID: PMC8432354 DOI: 10.1080/19491034.2021.1962610] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 07/26/2021] [Accepted: 07/27/2021] [Indexed: 01/10/2023] Open
Abstract
The nucleus, central to cellular activity, relies on both direct mechanical input as well as its molecular transducers to sense external stimuli and respond by regulating intra-nuclear chromatin organization that determines cell function and fate. In mesenchymal stem cells of musculoskeletal tissues, changes in nuclear structures are emerging as a key modulator of their differentiation and proliferation programs. In this review we will first introduce the structural elements of the nucleoskeleton and discuss the current literature on how nuclear structure and signaling are altered in relation to environmental and tissue level mechanical cues. We will focus on state-of-the-art techniques to apply mechanical force and methods to measure nuclear mechanics in conjunction with DNA, RNA, and protein visualization in living cells. Ultimately, combining real-time nuclear deformations and chromatin dynamics can be a powerful tool to study mechanisms of how forces affect the dynamics of genome function.
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Affiliation(s)
- Matthew Goelzer
- Materials Science and Engineering, Boise State University, Boise, ID, US
| | | | - Matthew L. Ferguson
- Biomolecular Science, Boise State University, Boise, ID, US
- Physics, Boise State University, Boise, ID, US
| | - Corey P. Neu
- Paul M. Rady Department of Mechanical Engineering, University of Colorado, Boulder, CO, US
| | - Gunes Uzer
- Mechanical and Biomedical Engineering, Boise State University, Boise, ID, US
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Lin CYG, Näger AC, Lunardi T, Vančevska A, Lossaint G, Lingner J. The human telomeric proteome during telomere replication. Nucleic Acids Res 2021; 49:12119-12135. [PMID: 34747482 PMCID: PMC8643687 DOI: 10.1093/nar/gkab1015] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 10/07/2021] [Accepted: 10/13/2021] [Indexed: 11/13/2022] Open
Abstract
Telomere shortening can cause detrimental diseases and contribute to aging. It occurs due to the end replication problem in cells lacking telomerase. Furthermore, recent studies revealed that telomere shortening can be attributed to difficulties of the semi-conservative DNA replication machinery to replicate the bulk of telomeric DNA repeats. To investigate telomere replication in a comprehensive manner, we develop QTIP-iPOND - Quantitative Telomeric chromatin Isolation Protocol followed by isolation of Proteins On Nascent DNA - which enables purification of proteins that associate with telomeres specifically during replication. In addition to the core replisome, we identify a large number of proteins that specifically associate with telomere replication forks. Depletion of several of these proteins induces telomere fragility validating their importance for telomere replication. We also find that at telomere replication forks the single strand telomere binding protein POT1 is depleted, whereas histone H1 is enriched. Our work reveals the dynamic changes of the telomeric proteome during replication, providing a valuable resource of telomere replication proteins. To our knowledge, this is the first study that examines the replisome at a specific region of the genome.
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Affiliation(s)
- Chih-Yi Gabriela Lin
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Anna Christina Näger
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Thomas Lunardi
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Aleksandra Vančevska
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Gérald Lossaint
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Joachim Lingner
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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40
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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: 10] [Impact Index Per Article: 3.3] [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.
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41
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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.
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Affiliation(s)
- Philipp Niethammer
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA;
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42
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Nuclear Dynamics and Chromatin Structure: Implications for Pancreatic Cancer. Cells 2021; 10:cells10102624. [PMID: 34685604 PMCID: PMC8534098 DOI: 10.3390/cells10102624] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Revised: 09/20/2021] [Accepted: 09/27/2021] [Indexed: 12/14/2022] Open
Abstract
Changes in nuclear shape have been extensively associated with the dynamics and functionality of cancer cells. In most normal cells, nuclei have a regular ellipsoid shape and minimal variation in nuclear size; however, an irregular nuclear contour and abnormal nuclear size is often observed in cancer, including pancreatic cancer. Furthermore, alterations in nuclear morphology have become the 'gold standard' for tumor staging and grading. Beyond the utility of altered nuclear morphology as a diagnostic tool in cancer, the implications of altered nuclear structure for the biology and behavior of cancer cells are profound as changes in nuclear morphology could impact cellular responses to physical strain, adaptation during migration, chromatin organization, and gene expression. Here, we aim to highlight and discuss the factors that regulate nuclear dynamics and their implications for pancreatic cancer biology.
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43
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Hernández-Guzmán C, Gallego-Gutiérrez H, Chávez-Munguía B, Martín-Tapia D, González-Mariscal L. Zonula occludens 2 and Cell-Cell Contacts Are Required for Normal Nuclear Shape in Epithelia. Cells 2021; 10:cells10102568. [PMID: 34685547 PMCID: PMC8534263 DOI: 10.3390/cells10102568] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 09/04/2021] [Accepted: 09/06/2021] [Indexed: 01/10/2023] Open
Abstract
MAGUK protein ZO-2 is present at tight junctions (TJs) and nuclei. In MDCK ZO-2 knockdown (KD) cells, nuclei exhibit an irregular shape with lobules and indentations. This condition correlates with an increase in DNA double strand breaks, however cells are not senescent and instead become resistant to UV-induced senescence. The irregular nuclear shape is also observed in isolated cells and in those without TJs, due to the lack of extracellular calcium. The aberrant nuclear shape of ZO-2 KD cells is not accompanied by a reduced expression of lamins A/C and B and lamin B receptors. Instead, it involves a decrease in constitutive and facultative heterochromatin, and microtubule instability that is restored with docetaxel. ZO-2 KD cells over-express SUN-1 that crosses the inner nuclear membrane and connects the nucleoskeleton of lamin A to nesprins, which traverse the outer nuclear membrane. Nesprins-3 and -4 that indirectly bind on their cytoplasmic face to vimentin and microtubules, respectively, are also over-expressed in ZO-2 KD cells, whereas vimentin is depleted. SUN-1 and lamin B1 co-immunoprecipitate with ZO-2, and SUN-1 associates to ZO-2 in a pull-down assay. Our results suggest that ZO-2 forms a complex with SUN-1 and lamin B1 at the inner nuclear membrane, and that ZO-2 and cell–cell contacts are required for a normal nuclear shape.
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Affiliation(s)
- Christian Hernández-Guzmán
- Center for Research and Advanced Studies (Cinvestav), Department of Physiology, Biophysics and Neuroscience, Ave IPN 2508, Mexico City 07360, Mexico; (C.H.-G.); (H.G.-G.); (D.M.-T.)
| | - Helios Gallego-Gutiérrez
- Center for Research and Advanced Studies (Cinvestav), Department of Physiology, Biophysics and Neuroscience, Ave IPN 2508, Mexico City 07360, Mexico; (C.H.-G.); (H.G.-G.); (D.M.-T.)
| | - Bibiana Chávez-Munguía
- Center for Research and Advanced Studies (Cinvestav), Department of Infectomics and Molecular Pathogenesis, Ave IPN 2508, Mexico City 07360, Mexico;
| | - Dolores Martín-Tapia
- Center for Research and Advanced Studies (Cinvestav), Department of Physiology, Biophysics and Neuroscience, Ave IPN 2508, Mexico City 07360, Mexico; (C.H.-G.); (H.G.-G.); (D.M.-T.)
| | - Lorenza González-Mariscal
- Center for Research and Advanced Studies (Cinvestav), Department of Physiology, Biophysics and Neuroscience, Ave IPN 2508, Mexico City 07360, Mexico; (C.H.-G.); (H.G.-G.); (D.M.-T.)
- Correspondence: ; Tel.: +52-55-5747-3966
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44
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Nader GPDF, Williart A, Piel M. Nuclear deformations, from signaling to perturbation and damage. Curr Opin Cell Biol 2021; 72:137-145. [PMID: 34461580 DOI: 10.1016/j.ceb.2021.07.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 07/13/2021] [Accepted: 07/28/2021] [Indexed: 01/07/2023]
Abstract
During cell growth and motility in crowded tissues or interstitial spaces, cells must integrate multiple physical and biochemical environmental inputs. After a number of recent studies, the view of the nucleus as a passive object that cells have to drag along has become obsolete, placing the nucleus as a central player in sensing some of these inputs. In the present review, we will focus on changes in nuclear shape caused by external and internal forces. Depending on their magnitude, nuclear deformations can generate signaling events that modulate cell behavior and fate, or be a source of perturbations or even damage, having detrimental effects on cellular functions. On very large deformations, nuclear envelope rupture events become frequent, leading to uncontrolled nucleocytoplasmic mixing and DNA damage. We will also discuss the consequences of repeated compromised nuclear integrity, which can trigger DNA surveillance mechanisms, with critical consequences to cell fate and tissue homeostasis.
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Affiliation(s)
| | - Alice Williart
- Institut Curie and Institut Pierre Gilles de Gennes, PSL Research University, CNRS, UMR 144, Paris, France
| | - Matthieu Piel
- Institut Curie and Institut Pierre Gilles de Gennes, PSL Research University, CNRS, UMR 144, Paris, France.
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45
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Lityagina O, Dobreva G. The LINC Between Mechanical Forces and Chromatin. Front Physiol 2021; 12:710809. [PMID: 34408666 PMCID: PMC8365421 DOI: 10.3389/fphys.2021.710809] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 07/14/2021] [Indexed: 12/26/2022] Open
Abstract
The heart continually senses and responds to mechanical stimuli that balance cardiac structure and activity. Tensile forces, compressive forces, and shear stress are sensed by the different cardiac cell types and converted into signals instructing proper heart morphogenesis, postnatal growth, and function. Defects in mechanotransduction, the ability of cells to convert mechanical stimuli into biochemical signals, are implicated in cardiovascular disease development and progression. In this review, we summarize the current knowledge on how mechanical forces are transduced to chromatin through the tensed actomyosin cytoskeleton, the linker of nucleoskeleton and cytoskeleton (LINC) complex and the nuclear lamina. We also discuss the functional significance of the LINC complex in cardiovascular disease.
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Affiliation(s)
- Olga Lityagina
- Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Gergana Dobreva
- Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.,German Centre for Cardiovascular Research (DZHK), Partner Site Heidelberg/Mannheim, Mannheim, Germany
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46
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Modelling Nuclear Morphology and Shape Transformation: A Review. MEMBRANES 2021; 11:membranes11070540. [PMID: 34357190 PMCID: PMC8304582 DOI: 10.3390/membranes11070540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 07/14/2021] [Accepted: 07/14/2021] [Indexed: 11/20/2022]
Abstract
As one of the most important cellular compartments, the nucleus contains genetic materials and separates them from the cytoplasm with the nuclear envelope (NE), a thin membrane that is susceptible to deformations caused by intracellular forces. Interestingly, accumulating evidence has also indicated that the morphology change of NE is tightly related to nuclear mechanotransduction and the pathogenesis of diseases such as cancer and Hutchinson–Gilford Progeria Syndrome. Theoretically, with the help of well-designed experiments, significant progress has been made in understanding the physical mechanisms behind nuclear shape transformation in different cellular processes as well as its biological implications. Here, we review different continuum-level (i.e., energy minimization, boundary integral and finite element-based) approaches that have been developed to predict the morphology and shape change of the cell nucleus. Essential gradients, relative advantages and limitations of each model will be discussed in detail, with the hope of sparking a greater research interest in this important topic in the future.
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47
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Gauthier BR, Comaills V. Nuclear Envelope Integrity in Health and Disease: Consequences on Genome Instability and Inflammation. Int J Mol Sci 2021; 22:ijms22147281. [PMID: 34298904 PMCID: PMC8307504 DOI: 10.3390/ijms22147281] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 07/02/2021] [Accepted: 07/04/2021] [Indexed: 12/11/2022] Open
Abstract
The dynamic nature of the nuclear envelope (NE) is often underestimated. The NE protects, regulates, and organizes the eukaryote genome and adapts to epigenetic changes and to its environment. The NE morphology is characterized by a wide range of diversity and abnormality such as invagination and blebbing, and it is a diagnostic factor for pathologies such as cancer. Recently, the micronuclei, a small nucleus that contains a full chromosome or a fragment thereof, has gained much attention. The NE of micronuclei is prone to collapse, leading to DNA release into the cytoplasm with consequences ranging from the activation of the cGAS/STING pathway, an innate immune response, to the creation of chromosomal instability. The discovery of those mechanisms has revolutionized the understanding of some inflammation-related diseases and the origin of complex chromosomal rearrangements, as observed during the initiation of tumorigenesis. Herein, we will highlight the complexity of the NE biology and discuss the clinical symptoms observed in NE-related diseases. The interplay between innate immunity, genomic instability, and nuclear envelope leakage could be a major focus in future years to explain a wide range of diseases and could lead to new classes of therapeutics.
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Affiliation(s)
- Benoit R. Gauthier
- Andalusian Center for Molecular Biology and Regenerative Medicine-CABIMER, Junta de Andalucía-University of Pablo de Olavide-University of Seville-CSIC, 41092 Seville, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 28029 Madrid, Spain
- Correspondence: (B.R.G.); (V.C.)
| | - Valentine Comaills
- Andalusian Center for Molecular Biology and Regenerative Medicine-CABIMER, Junta de Andalucía-University of Pablo de Olavide-University of Seville-CSIC, 41092 Seville, Spain
- Correspondence: (B.R.G.); (V.C.)
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48
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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.
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Affiliation(s)
- Philipp Niethammer
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA;
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49
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Strom AR, Biggs RJ, Banigan EJ, Wang X, Chiu K, Herman C, Collado J, Yue F, Ritland Politz JC, Tait LJ, Scalzo D, Telling A, Groudine M, Brangwynne CP, Marko JF, Stephens AD. HP1α is a chromatin crosslinker that controls nuclear and mitotic chromosome mechanics. eLife 2021; 10:e63972. [PMID: 34106828 PMCID: PMC8233041 DOI: 10.7554/elife.63972] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 06/08/2021] [Indexed: 12/14/2022] Open
Abstract
Chromatin, which consists of DNA and associated proteins, contains genetic information and is a mechanical component of the nucleus. Heterochromatic histone methylation controls nucleus and chromosome stiffness, but the contribution of heterochromatin protein HP1α (CBX5) is unknown. We used a novel HP1α auxin-inducible degron human cell line to rapidly degrade HP1α. Degradation did not alter transcription, local chromatin compaction, or histone methylation, but did decrease chromatin stiffness. Single-nucleus micromanipulation reveals that HP1α is essential to chromatin-based mechanics and maintains nuclear morphology, separate from histone methylation. Further experiments with dimerization-deficient HP1αI165E indicate that chromatin crosslinking via HP1α dimerization is critical, while polymer simulations demonstrate the importance of chromatin-chromatin crosslinkers in mechanics. In mitotic chromosomes, HP1α similarly bolsters stiffness while aiding in mitotic alignment and faithful segregation. HP1α is therefore a critical chromatin-crosslinking protein that provides mechanical strength to chromosomes and the nucleus throughout the cell cycle and supports cellular functions.
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Affiliation(s)
- Amy R Strom
- Howard Hughes Medical Institute, Department of Chemical and Biological Engineering, Princeton UniversityPrincetonUnited States
| | - Ronald J Biggs
- Department of Molecular Biosciences, Northwestern UniversityEvanstonUnited States
| | - Edward J Banigan
- Institute for Medical Engineering and Science and Department of Physics, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Xiaotao Wang
- Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern UniversityChicagoUnited States
| | - Katherine Chiu
- Biology Department, University of Massachusetts AmherstAmherstUnited States
| | - Cameron Herman
- Department of Molecular Biosciences, Northwestern UniversityEvanstonUnited States
| | - Jimena Collado
- Department of Molecular Biosciences, Northwestern UniversityEvanstonUnited States
| | - Feng Yue
- Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern UniversityChicagoUnited States
- Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern UniversityChicagoUnited States
| | | | - Leah J Tait
- The Fred Hutchinson Cancer Research CenterSeattleUnited States
| | - David Scalzo
- The Fred Hutchinson Cancer Research CenterSeattleUnited States
| | - Agnes Telling
- The Fred Hutchinson Cancer Research CenterSeattleUnited States
| | - Mark Groudine
- The Fred Hutchinson Cancer Research CenterSeattleUnited States
| | - Clifford P Brangwynne
- Howard Hughes Medical Institute, Department of Chemical and Biological Engineering, Princeton UniversityPrincetonUnited States
| | - John F Marko
- Department of Molecular Biosciences, Northwestern UniversityEvanstonUnited States
- Department of Physics and Astronomy, Northwestern UniversityEvanstonUnited States
| | - Andrew D Stephens
- Biology Department, University of Massachusetts AmherstAmherstUnited States
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50
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Pradhan S, Solomon R, Gangotra A, Yakubov GE, Willmott GR, Whitby CP, Hale TK, Williams MAK. Depletion of HP1α alters the mechanical properties of MCF7 nuclei. Biophys J 2021; 120:2631-2643. [PMID: 34087208 DOI: 10.1016/j.bpj.2021.05.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 05/11/2021] [Accepted: 05/14/2021] [Indexed: 11/27/2022] Open
Abstract
Within the nucleus of the eukaryotic cell, DNA is partitioned into domains of highly condensed, transcriptionally silent heterochromatin and less condensed, transcriptionally active euchromatin. Heterochromatin protein 1α (HP1α) is an architectural protein that establishes and maintains heterochromatin, ensuring genome fidelity and nuclear integrity. Although the mechanical effects of changes in the relative amount of euchromatin and heterochromatin brought about by inhibiting chromatin-modifying enzymes have been studied previously, here we measure how the material properties of the nuclei are modified after the knockdown of HP1α. These studies were inspired by the observation that poorly invasive MCF7 breast cancer cells become more invasive after knockdown of HP1α expression and that, indeed, in many solid tumors the loss of HP1α correlates with the onset of tumor cell invasion. Atomic force microscopy (AFM), optical tweezers (OT), and techniques based on micropipette aspiration (MA) were each used to characterize the mechanical properties of nuclei extracted from HP1α knockdown or matched control MCF7 cells. Using AFM or OT to locally indent nuclei, those extracted from MCF7 HP1α knockdown cells were found to have apparent Young's moduli that were significantly lower than nuclei from MCF7 control cells, consistent with previous studies that assert heterochromatin plays a major role in governing the mechanical response in such experiments. In contrast, results from pipette-based techniques in the spirit of MA, in which the whole nuclei were deformed and aspirated into a conical pipette, showed considerably less variation between HP1α knockdown and control, consistent with previous studies reporting that it is predominantly the lamins in the nuclear envelope that determine the mechanical response to large whole-cell deformations. The differences in chromatin organization observed by various microscopy techniques between the MCF7 control and HP1α knockdown nuclei correlate well with the results of our measured mechanical responses and our hypotheses regarding their origin.
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Affiliation(s)
- Susav Pradhan
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand; The MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, New Zealand
| | - Raoul Solomon
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Ankita Gangotra
- The MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, New Zealand; Department of Physics, The University of Auckland, Auckland, New Zealand
| | - Gleb E Yakubov
- School of Chemical Engineering, The University of Queensland, Brisbane, Australia; School of Biosciences, Faculty of Science, University of Nottingham, Nottingham, United Kingdom
| | - Geoff R Willmott
- The MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, New Zealand; Department of Physics, The University of Auckland, Auckland, New Zealand; School of Chemical Sciences, The University of Auckland, Auckland, New Zealand
| | - Catherine P Whitby
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand; The MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, New Zealand
| | - Tracy K Hale
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.
| | - Martin A K Williams
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand; The MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, New Zealand.
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