1
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Zou J, Peng B, Fan N, Liu Y. Simulation and experimental study on the influence of lamina on nanoneedle penetration into the cell nucleus. Biomech Model Mechanobiol 2024:10.1007/s10237-024-01836-4. [PMID: 38526703 DOI: 10.1007/s10237-024-01836-4] [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: 10/10/2023] [Accepted: 02/21/2024] [Indexed: 03/27/2024]
Abstract
We have developed a finite element model to simulate the penetration of nanoneedles into the cellular nucleus. It is found that the nuclear lamina, the primary supporting structure of the nuclear membrane, plays a crucial role in maintaining the integrity of the nuclear envelope and enhancing stress concentration in the nuclear membrane. Notably, nuclear lamina A exhibits a more pronounced effect compared to nuclear lamina B. Subsequently, we further conducted experiments by controlling the time of osteopontin (OPN) treatment to modify the nuclear lamina density, and the results showed that an increase in nuclear lamina density enhances the probability of nanoneedle penetration into the nuclear membrane. Through employing both simulation and experimental techniques, we have gathered compelling evidence indicating that an augmented density of nuclear lamina A can enhance the penetration of nanoneedles into the nuclear membrane.
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Affiliation(s)
- Jie Zou
- School of Mechatronics Engineering, University of Electronic Science and Technology of China, Chengdu, 611731, China
| | - Bei Peng
- School of Mechatronics Engineering, University of Electronic Science and Technology of China, Chengdu, 611731, China
| | - Na Fan
- School of Mechatronics Engineering, University of Electronic Science and Technology of China, Chengdu, 611731, China.
| | - Yang Liu
- College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065, China.
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2
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Tiwari V, Alam MJ, Bhatia M, Navya M, Banerjee SK. The structure and function of lamin A/C: Special focus on cardiomyopathy and therapeutic interventions. Life Sci 2024; 341:122489. [PMID: 38340979 DOI: 10.1016/j.lfs.2024.122489] [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: 11/11/2023] [Revised: 01/21/2024] [Accepted: 02/03/2024] [Indexed: 02/12/2024]
Abstract
Lamins are inner nuclear membrane proteins that belong to the intermediate filament family. Lamin A/C lie adjacent to the heterochromatin structure in polymer form, providing skeletal to the nucleus. Based on the localization, lamin A/C provides nuclear stability and cytoskeleton to the nucleus and modulates chromatin organization and gene expression. Besides being the structural protein making the inner nuclear membrane in polymer form, lamin A/C functions as a signalling molecule involved in gene expression as an enhancer inside the nucleus. Lamin A/C regulates various cellular pathways like autophagy and energy balance in the cytoplasm. Its expression is highly variable in differentiated tissues, higher in hard tissues like bone and muscle cells, and lower in soft tissues like the liver and brain. In muscle cells, including the heart, lamin A/C must be expressed in a balanced state. Lamin A/C mutation is linked with various diseases, such as muscular dystrophy, lipodystrophy, and cardiomyopathies. It has been observed that a good number of mutations in the LMNA gene impact cardiac activity and its function. Although several works have been published, there are still several unexplored areas left regarding the lamin A/C function and structure in the cardiovascular system and its pathological state. In this review, we focus on the structural organization, expression pattern, and function of lamin A/C, its interacting partners, and the pathophysiology associated with mutations in the lamin A/C gene, with special emphasis on cardiovascular diseases. With the recent finding on lamin A/C, we have summarized the possible therapeutic interventions to treat cardiovascular symptoms and reverse the molecular changes.
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Affiliation(s)
- Vikas Tiwari
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, Guwahati 781101, Assam, India
| | - Md Jahangir Alam
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, Guwahati 781101, Assam, India; Cell Biology and Physiology Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Madhavi Bhatia
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, Guwahati 781101, Assam, India
| | - Malladi Navya
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, Guwahati 781101, Assam, India
| | - Sanjay K Banerjee
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, Guwahati 781101, Assam, India.
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3
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Cisterna B, Malatesta M. Molecular and Structural Alterations of Skeletal Muscle Tissue Nuclei during Aging. Int J Mol Sci 2024; 25:1833. [PMID: 38339110 PMCID: PMC10855217 DOI: 10.3390/ijms25031833] [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: 12/27/2023] [Revised: 01/30/2024] [Accepted: 01/31/2024] [Indexed: 02/12/2024] Open
Abstract
Aging is accompanied by a progressive loss of skeletal muscle mass and strength. The mechanisms underlying this phenomenon are certainly multifactorial and still remain to be fully elucidated. Changes in the cell nucleus structure and function have been considered among the possible contributing causes. This review offers an overview of the current knowledge on skeletal muscle nuclei in aging, focusing on the impairment of nuclear pathways potentially involved in age-related muscle decline. In skeletal muscle two types of cells are present: fiber cells, constituting the contractile muscle mass and containing hundreds of myonuclei, and the satellite cells, i.e., the myogenic mononuclear stem cells occurring at the periphery of the fibers and responsible for muscle growth and repair. Research conducted on different experimental models and with different methodological approaches demonstrated that both the myonuclei and satellite cell nuclei of aged skeletal muscles undergo several structural and molecular alterations, affecting chromatin organization, gene expression, and transcriptional and post-transcriptional activities. These alterations play a key role in the impairment of muscle fiber homeostasis and regeneration, thus contributing to the age-related decrease in skeletal muscle mass and function.
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Affiliation(s)
| | - Manuela Malatesta
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Strada Le Grazie 8, 37134 Verona, Italy;
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4
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Seelbinder B, Wagner S, Jain M, Erben E, Klykov S, Stoev ID, Krishnaswamy VR, Kreysing M. Probe-free optical chromatin deformation and measurement of differential mechanical properties in the nucleus. eLife 2024; 13:e76421. [PMID: 38214505 PMCID: PMC10786458 DOI: 10.7554/elife.76421] [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: 12/15/2021] [Accepted: 11/29/2023] [Indexed: 01/13/2024] Open
Abstract
The nucleus is highly organized to facilitate coordinated gene transcription. Measuring the rheological properties of the nucleus and its sub-compartments will be crucial to understand the principles underlying nuclear organization. Here, we show that strongly localized temperature gradients (approaching 1°C/µm) can lead to substantial intra-nuclear chromatin displacements (>1 µm), while nuclear area and lamina shape remain unaffected. Using particle image velocimetry (PIV), intra-nuclear displacement fields can be calculated and converted into spatio-temporally resolved maps of various strain components. Using this approach, we show that chromatin displacements are highly reversible, indicating that elastic contributions are dominant in maintaining nuclear organization on the time scale of seconds. In genetically inverted nuclei, centrally compacted heterochromatin displays high resistance to deformation, giving a rigid, solid-like appearance. Correlating spatially resolved strain maps with fluorescent reporters in conventional interphase nuclei reveals that various nuclear compartments possess distinct mechanical identities. Surprisingly, both densely and loosely packed chromatin showed high resistance to deformation, compared to medium dense chromatin. Equally, nucleoli display particularly high resistance and strong local anchoring to heterochromatin. Our results establish how localized temperature gradients can be used to drive nuclear compartments out of mechanical equilibrium to obtain spatial maps of their material responses.
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Affiliation(s)
- Benjamin Seelbinder
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Centre for Systems BiologyDresdenGermany
| | - Susan Wagner
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Institute of Biological and Chemical Systems-Biological Information Processing, Karlsruhe Institute of TechnologyEggenstein-LeopoldshafenGermany
| | - Manavi Jain
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Centre for Systems BiologyDresdenGermany
| | - Elena Erben
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Centre for Systems BiologyDresdenGermany
| | - Sergei Klykov
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Centre for Systems BiologyDresdenGermany
| | - Iliya Dimitrov Stoev
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Centre for Systems BiologyDresdenGermany
| | | | - Moritz Kreysing
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Centre for Systems BiologyDresdenGermany
- Institute of Biological and Chemical Systems-Biological Information Processing, Karlsruhe Institute of TechnologyEggenstein-LeopoldshafenGermany
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5
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Xin Y, Li K, Huang M, Liang C, Siemann D, Wu L, Tan Y, Tang X. Biophysics in tumor growth and progression: from single mechano-sensitive molecules to mechanomedicine. Oncogene 2023; 42:3457-3490. [PMID: 37864030 PMCID: PMC10656290 DOI: 10.1038/s41388-023-02844-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 09/08/2023] [Accepted: 09/15/2023] [Indexed: 10/22/2023]
Abstract
Evidence from physical sciences in oncology increasingly suggests that the interplay between the biophysical tumor microenvironment and genetic regulation has significant impact on tumor progression. Especially, tumor cells and the associated stromal cells not only alter their own cytoskeleton and physical properties but also remodel the microenvironment with anomalous physical properties. Together, these altered mechano-omics of tumor tissues and their constituents fundamentally shift the mechanotransduction paradigms in tumorous and stromal cells and activate oncogenic signaling within the neoplastic niche to facilitate tumor progression. However, current findings on tumor biophysics are limited, scattered, and often contradictory in multiple contexts. Systematic understanding of how biophysical cues influence tumor pathophysiology is still lacking. This review discusses recent different schools of findings in tumor biophysics that have arisen from multi-scale mechanobiology and the cutting-edge technologies. These findings range from the molecular and cellular to the whole tissue level and feature functional crosstalk between mechanotransduction and oncogenic signaling. We highlight the potential of these anomalous physical alterations as new therapeutic targets for cancer mechanomedicine. This framework reconciles opposing opinions in the field, proposes new directions for future cancer research, and conceptualizes novel mechanomedicine landscape to overcome the inherent shortcomings of conventional cancer diagnosis and therapies.
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Grants
- R35 GM150812 NIGMS NIH HHS
- This work was financially supported by National Natural Science Foundation of China (Project no. 11972316, Y.T.), Shenzhen Science and Technology Innovation Commission (Project no. JCYJ20200109142001798, SGDX2020110309520303, and JCYJ20220531091002006, Y.T.), General Research Fund of Hong Kong Research Grant Council (PolyU 15214320, Y. T.), Health and Medical Research Fund (HMRF18191421, Y.T.), Hong Kong Polytechnic University (1-CD75, 1-ZE2M, and 1-ZVY1, Y.T.), the Cancer Pilot Research Award from UF Health Cancer Center (X. T.), the National Institute of General Medical Sciences of the National Institutes of Health under award number R35GM150812 (X. T.), the National Science Foundation under grant number 2308574 (X. T.), the Air Force Office of Scientific Research under award number FA9550-23-1-0393 (X. T.), the University Scholar Program (X. T.), UF Research Opportunity Seed Fund (X. T.), the Gatorade Award (X. T.), and the National Science Foundation REU Site at UF: Engineering for Healthcare (Douglas Spearot and Malisa Sarntinoranont). We are deeply grateful for the insightful discussions with and generous support from all members of Tang (UF)’s and Tan (PolyU)’s laboratories and all staff members of the MAE/BME/ECE/Health Cancer Center at UF and BME at PolyU.
- National Natural Science Foundation of China (National Science Foundation of China)
- Shenzhen Science and Technology Innovation Commission
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Affiliation(s)
- Ying Xin
- The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, China
| | - Keming Li
- The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, China
| | - Miao Huang
- Department of Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, FL, USA
| | - Chenyu Liang
- Department of Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, FL, USA
| | - Dietmar Siemann
- UF Health Cancer Center, University of Florida, Gainesville, FL, USA
| | - Lizi Wu
- UF Health Cancer Center, University of Florida, Gainesville, FL, USA
| | - Youhua Tan
- The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, China.
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong, China.
- Research Institute of Smart Ageing, The Hong Kong Polytechnic University, Hong Kong, China.
| | - Xin Tang
- Department of Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, FL, USA.
- UF Health Cancer Center, University of Florida, Gainesville, FL, USA.
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA.
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL, USA.
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6
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Buxboim A, Kronenberg-Tenga R, Salajkova S, Avidan N, Shahak H, Thurston A, Medalia O. Scaffold, mechanics and functions of nuclear lamins. FEBS Lett 2023; 597:2791-2805. [PMID: 37813648 DOI: 10.1002/1873-3468.14750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 09/05/2023] [Accepted: 09/26/2023] [Indexed: 10/11/2023]
Abstract
Nuclear lamins are type-V intermediate filaments that are involved in many nuclear processes. In mammals, A- and B-type lamins assemble into separate physical meshwork underneath the inner nuclear membrane, the nuclear lamina, with some residual fraction localized within the nucleoplasm. Lamins are the major part of the nucleoskeleton, providing mechanical strength and flexibility to protect the genome and allow nuclear deformability, while also contributing to gene regulation via interactions with chromatin. While lamins are the evolutionary ancestors of all intermediate filament family proteins, their ultimate filamentous assembly is markedly different from their cytoplasmic counterparts. Interestingly, hundreds of genetic mutations in the lamina proteins have been causally linked with a broad range of human pathologies, termed laminopathies. These include muscular, neurological and metabolic disorders, as well as premature aging diseases. Recent technological advances have contributed to resolving the filamentous structure of lamins and the corresponding lamina organization. In this review, we revisit the multiscale lamin organization and discuss its implications on nuclear mechanics and chromatin organization within lamina-associated domains.
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Affiliation(s)
- Amnon Buxboim
- The Rachel and Selim Benin School of Computer Science and Engineering and The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Israel
| | | | - Sarka Salajkova
- Department of Biochemistry, University of Zurich, Switzerland
| | - Nili Avidan
- The Rachel and Selim Benin School of Computer Science and Engineering and The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Israel
| | - Hen Shahak
- The Rachel and Selim Benin School of Computer Science and Engineering and The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Israel
| | - Alice Thurston
- Department of Biochemistry, University of Zurich, Switzerland
| | - Ohad Medalia
- Department of Biochemistry, University of Zurich, Switzerland
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7
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Khan A, Metts JM, Collins LC, Mills CA, Li K, Brademeyer AL, Bowman BM, Major MB, Aubé J, Herring LE, Davis IJ, Strahl BD. SETD2 maintains nuclear lamina stability to safeguard the genome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.28.560032. [PMID: 37808753 PMCID: PMC10557632 DOI: 10.1101/2023.09.28.560032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Histone methyltransferases play essential roles in the organization and function of chromatin. They are also frequently mutated in human diseases including cancer1. One such often mutated methyltransferase, SETD2, associates co-transcriptionally with RNA polymerase II and catalyzes histone H3 lysine 36 trimethylation (H3K36me3) - a modification that contributes to gene transcription, splicing, and DNA repair2. While studies on SETD2 have largely focused on the consequences of its catalytic activity, the non-catalytic functions of SETD2 are largely unknown. Here we report a catalysis-independent function of SETD2 in maintaining nuclear lamina stability and genome integrity. We found that SETD2, via its intrinsically disordered N-terminus, associates with nuclear lamina proteins including lamin A/C, lamin B1, and emerin. Depletion of SETD2, or deletion of its N-terminus, resulted in widespread nuclear morphology abnormalities and genome stability defects that were reminiscent of a defective nuclear lamina. Mechanistically, the N-terminus of SETD2 facilitates the association of the mitotic kinase CDK1 with lamins, thereby promoting lamin phosphorylation and depolymerization required for nuclear envelope disassembly during mitosis. Taken together, our findings reveal an unanticipated link between the N-terminus of SETD2 and nuclear lamina organization that may underlie how SETD2 acts as a tumor suppressor.
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Affiliation(s)
- Abid Khan
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - James M. Metts
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Lucas C. Collins
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - C. Allie Mills
- UNC Proteomics Core Facility, Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina, 27599, USA
| | - Kelin Li
- Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Amanda L. Brademeyer
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Brittany M. Bowman
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599, USA
- Department of Cell Biology & Physiology, Washington University in St. Louis
| | - M. Ben Major
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599, USA
- Department of Cell Biology & Physiology, Washington University in St. Louis
| | - Jeffrey Aubé
- Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Laura E. Herring
- UNC Proteomics Core Facility, Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina, 27599, USA
| | - Ian J. Davis
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599, USA
- Department of Pediatrics, University of North Carolina, Chapel Hill, North Carolina 27514
| | - Brian D. Strahl
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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8
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Mäntylä E, Montonen T, Azzari L, Mattola S, Hannula M, Vihinen-Ranta M, Hyttinen J, Vippola M, Foi A, Nymark S, Ihalainen TO. Iterative immunostaining combined with expansion microscopy and image processing reveals nanoscopic network organization of nuclear lamina. Mol Biol Cell 2023; 34:br13. [PMID: 37342871 PMCID: PMC10398900 DOI: 10.1091/mbc.e22-09-0448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 04/14/2023] [Accepted: 06/12/2023] [Indexed: 06/23/2023] Open
Abstract
Investigation of nuclear lamina architecture relies on superresolved microscopy. However, epitope accessibility, labeling density, and detection precision of individual molecules pose challenges within the molecularly crowded nucleus. We developed iterative indirect immunofluorescence (IT-IF) staining approach combined with expansion microscopy (ExM) and structured illumination microscopy to improve superresolution microscopy of subnuclear nanostructures like lamins. We prove that ExM is applicable in analyzing highly compacted nuclear multiprotein complexes such as viral capsids and provide technical improvements to ExM method including three-dimensional-printed gel casting equipment. We show that in comparison with conventional immunostaining, IT-IF results in a higher signal-to-background ratio and a mean fluorescence intensity by improving the labeling density. Moreover, we present a signal-processing pipeline for noise estimation, denoising, and deblurring to aid in quantitative image analyses and provide this platform for the microscopy imaging community. Finally, we show the potential of signal-resolved IT-IF in quantitative superresolution ExM imaging of nuclear lamina and reveal nanoscopic details of the lamin network organization-a prerequisite for studying intranuclear structural coregulation of cell function and fate.
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Affiliation(s)
- Elina Mäntylä
- BioMediTech, Faculty of Medicine and Health Technology, Tampere University, 33100 Tampere, Finland
| | - Toni Montonen
- BioMediTech, Faculty of Medicine and Health Technology, Tampere University, 33100 Tampere, Finland
| | - Lucio Azzari
- Tampere Microscopy Center (TMC), Tampere University, 33100 Tampere, Finland
| | - Salla Mattola
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, 40014 Jyväskylä, Finland
| | - Markus Hannula
- BioMediTech, Faculty of Medicine and Health Technology, Tampere University, 33100 Tampere, Finland
| | - Maija Vihinen-Ranta
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, 40014 Jyväskylä, Finland
| | - Jari Hyttinen
- BioMediTech, Faculty of Medicine and Health Technology, Tampere University, 33100 Tampere, Finland
| | - Minnamari Vippola
- Tampere Microscopy Center (TMC), Tampere University, 33100 Tampere, Finland
| | - Alessandro Foi
- Faculty of Information Technology and Communication Sciences, Computing Sciences, Tampere University, 33100 Tampere, Finland
| | - Soile Nymark
- BioMediTech, Faculty of Medicine and Health Technology, Tampere University, 33100 Tampere, Finland
| | - Teemu O. Ihalainen
- BioMediTech, Faculty of Medicine and Health Technology, Tampere University, 33100 Tampere, Finland
- Tampere Institute for Advanced Study, Tampere University, 33100 Tampere, Finland
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9
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Oses C, De Rossi MC, Bruno L, Verneri P, Diaz MC, Benítez B, Guberman A, Levi V. From the membrane to the nucleus: mechanical signals and transcription regulation. Biophys Rev 2023; 15:671-683. [PMID: 37681098 PMCID: PMC10480138 DOI: 10.1007/s12551-023-01103-3] [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: 04/06/2023] [Accepted: 07/20/2023] [Indexed: 09/09/2023] Open
Abstract
Mechanical forces drive and modulate a wide variety of processes in eukaryotic cells including those occurring in the nucleus. Relevantly, forces are fundamental during development since they guide lineage specifications of embryonic stem cells. A sophisticated macromolecular machinery transduces mechanical stimuli received at the cell surface into a biochemical output; a key component in this mechanical communication is the cytoskeleton, a complex network of biofilaments in constant remodeling that links the cell membrane to the nuclear envelope. Recent evidence highlights that forces transmitted through the cytoskeleton directly affect the organization of chromatin and the accessibility of transcription-related molecules to their targets in the DNA. Consequently, mechanical forces can directly modulate transcription and change gene expression programs. Here, we will revise the biophysical toolbox involved in the mechanical communication with the cell nucleus and discuss how mechanical forces impact on the organization of this organelle and more specifically, on transcription. We will also discuss how live-cell fluorescence imaging is producing exquisite information to understand the mechanical response of cells and to quantify the landscape of interactions of transcription factors with chromatin in embryonic stem cells. These studies are building new biophysical insights that could be fundamental to achieve the goal of manipulating forces to guide cell differentiation in culture systems.
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Affiliation(s)
- Camila Oses
- Instituto de Química Biológica de La Facultad de Ciencias Exactas Y Naturales (IQUIBICEN), Facultad de Ciencias Exactas Y Naturales, CONICET-Universidad de Buenos Aires, C1428EGA Buenos Aires, Argentina
| | - María Cecilia De Rossi
- Instituto de Química Biológica de La Facultad de Ciencias Exactas Y Naturales (IQUIBICEN), Facultad de Ciencias Exactas Y Naturales, CONICET-Universidad de Buenos Aires, C1428EGA Buenos Aires, Argentina
| | - Luciana Bruno
- Facultad de Ciencias Exactas Y Naturales, Instituto de Cálculo (IC), CONICET-Universidad de Buenos Aires, C1428EGA Buenos Aires, Argentina
| | - Paula Verneri
- Instituto de Química Biológica de La Facultad de Ciencias Exactas Y Naturales (IQUIBICEN), Facultad de Ciencias Exactas Y Naturales, CONICET-Universidad de Buenos Aires, C1428EGA Buenos Aires, Argentina
| | - María Candelaria Diaz
- Instituto de Química Biológica de La Facultad de Ciencias Exactas Y Naturales (IQUIBICEN), Facultad de Ciencias Exactas Y Naturales, CONICET-Universidad de Buenos Aires, C1428EGA Buenos Aires, Argentina
| | - Belén Benítez
- Instituto de Fisiología, Biología Molecular Y Neurociencias (IFIBYNE), Facultad de Ciencias Exactas Y Naturales, CONICET-Universidad de Buenos Aires, C1428EGA Buenos Aires, Argentina
| | - Alejandra Guberman
- Instituto de Química Biológica de La Facultad de Ciencias Exactas Y Naturales (IQUIBICEN), Facultad de Ciencias Exactas Y Naturales, CONICET-Universidad de Buenos Aires, C1428EGA Buenos Aires, Argentina
- Facultad de Ciencias Exactas Y Naturales, Departamento de Fisiología, Universidad de Buenos Aires, Biología Molecular Y Celular, C1428EGA Buenos Aires, Argentina
| | - Valeria Levi
- Instituto de Química Biológica de La Facultad de Ciencias Exactas Y Naturales (IQUIBICEN), Facultad de Ciencias Exactas Y Naturales, CONICET-Universidad de Buenos Aires, C1428EGA Buenos Aires, Argentina
- Facultad de Ciencias Exactas Y Naturales, Departamento de Química Biológica, Universidad de Buenos Aires, C1428EGA Buenos Aires, Argentina
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10
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Orsi GA, Tortora MMC, Horard B, Baas D, Kleman JP, Bucevičius J, Lukinavičius G, Jost D, Loppin B. Biophysical ordering transitions underlie genome 3D re-organization during cricket spermiogenesis. Nat Commun 2023; 14:4187. [PMID: 37443316 PMCID: PMC10345107 DOI: 10.1038/s41467-023-39908-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 06/30/2023] [Indexed: 07/15/2023] Open
Abstract
Spermiogenesis is a radical process of differentiation whereby sperm cells acquire a compact and specialized morphology to cope with the constraints of sexual reproduction while preserving their main cargo, an intact copy of the paternal genome. In animals, this often involves the replacement of most histones by sperm-specific nuclear basic proteins (SNBPs). Yet, how the SNBP-structured genome achieves compaction and accommodates shaping remain largely unknown. Here, we exploit confocal, electron and super-resolution microscopy, coupled with polymer modeling to identify the higher-order architecture of sperm chromatin in the needle-shaped nucleus of the emerging model cricket Gryllus bimaculatus. Accompanying spermatid differentiation, the SNBP-based genome is strikingly reorganized as ~25nm-thick fibers orderly coiled along the elongated nucleus axis. This chromatin spool is further found to achieve large-scale helical twisting in the final stages of spermiogenesis, favoring its ultracompaction. We reveal that these dramatic transitions may be recapitulated by a surprisingly simple biophysical principle based on a nucleated rigidification of chromatin linked to the histone-to-SNBP transition within a confined nuclear space. Our work highlights a unique, liquid crystal-like mode of higher-order genome organization in ultracompact cricket sperm, and establishes a multidisciplinary methodological framework to explore the diversity of non-canonical modes of DNA organization.
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Affiliation(s)
- Guillermo A Orsi
- Institute for Advanced Biosciences, University Grenoble Alpes, Inserm U 1209, CNRS UMR 5309, 38000, Grenoble, France.
| | - Maxime M C Tortora
- Laboratoire de Biologie et Modélisation de la Cellule, École Normale Supérieure de Lyon, CNRS UMR5239, Inserm U1293, Université Claude Bernard Lyon 1, Lyon, France
- Department of Quantitative and Computational Biology, University of Southern California, Los Angeles, CA, USA
| | - Béatrice Horard
- Laboratoire de Biologie et Modélisation de la Cellule, École Normale Supérieure de Lyon, CNRS UMR5239, Inserm U1293, Université Claude Bernard Lyon 1, Lyon, France
| | - Dominique Baas
- Laboratoire MeLiS, CNRS UMR 52684, Inserm U 1314, Institut NeuroMyoGène, Université Claude Bernard Lyon 1, Lyon, France
| | - Jean-Philippe Kleman
- Institut de Biologie Structurale, UMR5075, University Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - Jonas Bucevičius
- Chromatin Labeling and Imaging Group, Department of NanoBiophotonics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Gražvydas Lukinavičius
- Chromatin Labeling and Imaging Group, Department of NanoBiophotonics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Daniel Jost
- Laboratoire de Biologie et Modélisation de la Cellule, École Normale Supérieure de Lyon, CNRS UMR5239, Inserm U1293, Université Claude Bernard Lyon 1, Lyon, France.
| | - Benjamin Loppin
- Laboratoire de Biologie et Modélisation de la Cellule, École Normale Supérieure de Lyon, CNRS UMR5239, Inserm U1293, Université Claude Bernard Lyon 1, Lyon, France.
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11
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Marshall WF, Fung JC. Homologous chromosome recognition via nonspecific interactions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.09.544427. [PMID: 37333079 PMCID: PMC10274854 DOI: 10.1101/2023.06.09.544427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
In many organisms, most notably Drosophila, homologous chromosomes in somatic cells associate with each other, a phenomenon known as somatic homolog pairing. Unlike in meiosis, where homology is read out at the level of DNA sequence complementarity, somatic homolog pairing takes place without double strand breaks or strand invasion, thus requiring some other mechanism for homologs to recognize each other. Several studies have suggested a "specific button" model, in which a series of distinct regions in the genome, known as buttons, can associate with each other, presumably mediated by different proteins that bind to these different regions. Here we consider an alternative model, which we term the "button barcode" model, in which there is only one type of recognition site or adhesion button, present in many copies in the genome, each of which can associate with any of the others with equal affinity. An important component of this model is that the buttons are non-uniformly distributed, such that alignment of a chromosome with its correct homolog, compared with a non-homolog, is energetically favored; since to achieve nonhomologous alignment, chromosomes would be required to mechanically deform in order to bring their buttons into mutual register. We investigated several types of barcodes and examined their effect on pairing fidelity. We found that high fidelity homolog recognition can be achieved by arranging chromosome pairing buttons according to an actual industrial barcode used for warehouse sorting. By simulating randomly generated non-uniform button distributions, many highly effective button barcodes can be easily found, some of which achieve virtually perfect pairing fidelity. This model is consistent with existing literature on the effect of translocations of different sizes on homolog pairing. We conclude that a button barcode model can attain highly specific homolog recognition, comparable to that seen in actual cells undergoing somatic homolog pairing, without the need for specific interactions. This model may have implications for how meiotic pairing is achieved.
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12
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Dickinson RB, Lele TP. Nuclear shapes are geometrically determined by the excess surface area of the nuclear lamina. Front Cell Dev Biol 2023; 11:1058727. [PMID: 37397244 PMCID: PMC10308086 DOI: 10.3389/fcell.2023.1058727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 05/30/2023] [Indexed: 07/04/2023] Open
Abstract
Introduction: Nuclei have characteristic shapes dependent on cell type, which are critical for proper cell function, and nuclei lose their distinct shapes in multiple diseases including cancer, laminopathies, and progeria. Nuclear shapes result from deformations of the sub-nuclear components-nuclear lamina and chromatin. How these structures respond to cytoskeletal forces to form the nuclear shape remains unresolved. Although the mechanisms regulating nuclear shape in human tissues are not fully understood, it is known that different nuclear shapes arise from cumulative nuclear deformations post-mitosis, ranging from the rounded morphologies that develop immediately after mitosis to the various nuclear shapes that roughly correspond to cell shape (e.g., elongated nuclei in elongated cells, flat nuclei in flat cells). Methods: We formulated a mathematical model to predict nuclear shapes of cells in various contexts under the geometric constraints of fixed cell volume, nuclear volume and lamina surface area. Nuclear shapes were predicted and compared to experiments for cells in various geometries, including isolated on a flat surface, on patterned rectangles and lines, within a monolayer, isolated in a well, or when the nucleus is impinging against a slender obstacle. Results and Discussion: The close agreement between predicted and experimental shapes demonstrates a simple geometric principle of nuclear shaping: the excess surface area of the nuclear lamina (relative to that of a sphere of the same volume) permits a wide range of highly deformed nuclear shapes under the constraints of constant surface area and constant volume. When the lamina is smooth (tensed), the nuclear shape can be predicted entirely from these geometric constraints alone for a given cell shape. This principle explains why flattened nuclear shapes in fully spread cells are insensitive to the magnitude of the cytoskeletal forces. Also, the surface tension in the nuclear lamina and nuclear pressure can be estimated from the predicted cell and nuclear shapes when the cell cortical tension is known, and the predictions are consistent with measured forces. These results show that excess surface area of the nuclear lamina is the key determinant of nuclear shapes. When the lamina is smooth (tensed), the nuclear shape can be determined purely by the geometric constraints of constant (but excess) nuclear surface area, nuclear volume, and cell volume, for a given cell adhesion footprint, independent of the magnitude of the cytoskeletal forces involved.
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Affiliation(s)
- Richard B. Dickinson
- Department of Chemical Engineering, University of Florida, Gainesville, FL, United States
| | - Tanmay P. Lele
- Department of Biomedical Engineering, College of Engineering, Texas A&M University College Station, College Station, TX, United States
- Artie McFerrin Department of Chemical Engineering, College of Engineering, Texas A&M University, College Station, TX, United States
- Department of Translational Medical Sciences, Texas A&M University, College Station, TX, United States
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13
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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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14
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Tortora MMC, Jost D. Orientational Wetting and Topological Transitions in Confined Solutions of Semiflexible Polymers. Macromolecules 2023. [DOI: 10.1021/acs.macromol.2c02350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Affiliation(s)
- Maxime M. C. Tortora
- Université de Lyon, ENS de Lyon, Université Claude Bernard, CNRS, Laboratoire de Biologie et Modélisation de la Cellule, 69364 Lyon CEDEX 07, France
| | - Daniel Jost
- Université de Lyon, ENS de Lyon, Université Claude Bernard, CNRS, Laboratoire de Biologie et Modélisation de la Cellule, 69364 Lyon CEDEX 07, France
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15
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Xin L, Wen Y, Song J, Chen T, Zhai Q. Bone regeneration strategies based on organelle homeostasis of mesenchymal stem cells. Front Endocrinol (Lausanne) 2023; 14:1151691. [PMID: 37033227 PMCID: PMC10081449 DOI: 10.3389/fendo.2023.1151691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 03/06/2023] [Indexed: 04/11/2023] Open
Abstract
The organelle modulation has emerged as a crucial contributor to the organismal homeostasis. The mesenchymal stem cells (MSCs), with their putative functions in maintaining the regeneration ability of adult tissues, have been identified as a major driver to underlie skeletal health. Bone is a structural and endocrine organ, in which the organelle regulation on mesenchymal stem cells (MSCs) function has most been discovered recently. Furthermore, potential treatments to control bone regeneration are developing using organelle-targeted techniques based on manipulating MSCs osteogenesis. In this review, we summarize the most current understanding of organelle regulation on MSCs in bone homeostasis, and to outline mechanistic insights as well as organelle-targeted approaches for accelerated bone regeneration.
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Affiliation(s)
- Liangjing Xin
- College of Stomatology, Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory for Oral Diseases and Biomedical Sciences, Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Yao Wen
- College of Stomatology, Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory for Oral Diseases and Biomedical Sciences, Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Jinlin Song
- College of Stomatology, Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory for Oral Diseases and Biomedical Sciences, Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
- *Correspondence: Qiming Zhai, ; Tao Chen, ; Jinlin Song,
| | - Tao Chen
- College of Stomatology, Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory for Oral Diseases and Biomedical Sciences, Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
- *Correspondence: Qiming Zhai, ; Tao Chen, ; Jinlin Song,
| | - Qiming Zhai
- College of Stomatology, Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory for Oral Diseases and Biomedical Sciences, Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
- *Correspondence: Qiming Zhai, ; Tao Chen, ; Jinlin Song,
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16
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Efremov AK, Hovan L, Yan J. Nucleus size and its effect on nucleosome stability in living cells. Biophys J 2022; 121:4189-4204. [PMID: 36146936 PMCID: PMC9675033 DOI: 10.1016/j.bpj.2022.09.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 08/15/2022] [Accepted: 09/16/2022] [Indexed: 11/25/2022] Open
Abstract
DNA architectural proteins play a major role in organization of chromosomal DNA in living cells by packaging it into chromatin, whose spatial conformation is determined by an intricate interplay between the DNA-binding properties of architectural proteins and physical constraints applied to the DNA by a tight nuclear space. Yet, the exact effects of the nucleus size on DNA-protein interactions and chromatin structure currently remain obscure. Furthermore, there is even no clear understanding of molecular mechanisms responsible for the nucleus size regulation in living cells. To find answers to these questions, we developed a general theoretical framework based on a combination of polymer field theory and transfer-matrix calculations, which showed that the nucleus size is mainly determined by the difference between the surface tensions of the nuclear envelope and the endoplasmic reticulum membrane as well as the osmotic pressure exerted by cytosolic macromolecules on the nucleus. In addition, the model demonstrated that the cell nucleus functions as a piezoelectric element, changing its electrostatic potential in a size-dependent manner. This effect has been found to have a profound impact on stability of nucleosomes, revealing a previously unknown link between the nucleus size and chromatin structure. Overall, our study provides new insights into the molecular mechanisms responsible for regulation of the nucleus size, as well as the potential role of nuclear organization in shaping the cell response to environmental cues.
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Affiliation(s)
- Artem K Efremov
- Institute of Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen, China; Mechanobiology Institute, National University of Singapore, Singapore, Singapore.
| | - Ladislav Hovan
- School of Pharmaceutical Sciences, University of Geneva, Geneva, Switzerland
| | - Jie Yan
- Mechanobiology Institute, National University of Singapore, Singapore, Singapore
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17
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Choi Y, Morlino G, Toboso-Navasa A, Hopf R, Pramotton FM, Bigot A, Taddei A, Cesarovic N, Falk V, Mazza E, Giampietro C. A novel bistable device to study mechanosensitive cell responses to instantaneous stretch. BIOMATERIALS ADVANCES 2022; 141:213134. [PMID: 36191540 DOI: 10.1016/j.bioadv.2022.213134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 08/17/2022] [Accepted: 09/25/2022] [Indexed: 06/16/2023]
Abstract
The behavior of cells and tissues in vivo is determined by the integration of multiple biochemical and mechanical signals. Of the mechanical signals, stretch has been studied for decades and shown to contribute to pathophysiological processes. Several different stretch devices have been developed for in vitro investigations of cell stretch. In this work, we describe a new 3D-printed uniaxial stretching device for studying cell response to rapid deformation. The device is a bistable compliant mechanism holding two equilibrium states-an unstretched and stretched configuration-without the need of an external actuator. Furthermore, it allows multiple simultaneous measurements of different levels of stretch on a single substrate and is compatible with standard immunofluorescence imaging of fixed cells as well as live-cell imaging. To demonstrate the effectiveness of the device to stretch cells, a test case using aligned myotubes is presented. Leveraging material area changes associated with deformation of the substrate, changes in nuclei density provided evidence of affine deformation between cells and substrate. Furthermore, intranuclear deformations were also assessed and shown to deform non-affinely. As a proof-of-principle of the use of the device for mechanobiological studies, we uniaxially stretched aligned healthy and dystrophic myotubes that displayed different passive mechanical responses, consistent with previous literature in the field. We also identified a new feature in the mechanoresponse of dystrophic myotubes, which is of potential interest for identifying the diseased cells based on a quick mechanical readout. While some applications of the device for elucidating passive mechanical responses are demonstrated, the simplicity of the device allows it to be potentially used for other modes of deformation with little modifications.
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Affiliation(s)
- Young Choi
- Department of Mechanical and Process Engineering, ETH Zurich, Zurich 8092, Switzerland
| | | | | | - Raoul Hopf
- Department of Mechanical and Process Engineering, ETH Zurich, Zurich 8092, Switzerland; Swiss Federal Laboratories for Materials Science and Technology (EMPA), Dübendorf 8600, Switzerland; Senecell AG, Zurich 8057, Switzerland
| | - Francesca Michela Pramotton
- Department of Mechanical and Process Engineering, ETH Zurich, Zurich 8092, Switzerland; Swiss Federal Laboratories for Materials Science and Technology (EMPA), Dübendorf 8600, Switzerland
| | - Anne Bigot
- Sorbonne Université, Inserm, Institut de Myologie, Centre de Recherche en Myologie, F-75013 Paris, France
| | | | - Nikola Cesarovic
- Department of Health Sciences and Technology, ETH Zurich, Zurich 8092, Switzerland; Charité - Universitätsmedizin Berlin, Berlin 10117, Germany
| | - Volkmar Falk
- Department of Health Sciences and Technology, ETH Zurich, Zurich 8092, Switzerland; Charité - Universitätsmedizin Berlin, Berlin 10117, Germany
| | - Edoardo Mazza
- Department of Mechanical and Process Engineering, ETH Zurich, Zurich 8092, Switzerland; Swiss Federal Laboratories for Materials Science and Technology (EMPA), Dübendorf 8600, Switzerland.
| | - Costanza Giampietro
- Department of Mechanical and Process Engineering, ETH Zurich, Zurich 8092, Switzerland; Swiss Federal Laboratories for Materials Science and Technology (EMPA), Dübendorf 8600, Switzerland; Senecell AG, Zurich 8057, Switzerland.
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18
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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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19
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Infante E, Etienne-Manneville S. Intermediate filaments: Integration of cell mechanical properties during migration. Front Cell Dev Biol 2022; 10:951816. [PMID: 35990612 PMCID: PMC9389290 DOI: 10.3389/fcell.2022.951816] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 07/07/2022] [Indexed: 11/22/2022] Open
Abstract
Cell migration is a vital and dynamic process required for the development of multicellular organisms and for immune system responses, tissue renewal and wound healing in adults. It also contributes to a variety of human diseases such as cancers, autoimmune diseases, chronic inflammation and fibrosis. The cytoskeleton, which includes actin microfilaments, microtubules, and intermediate filaments (IFs), is responsible for the maintenance of animal cell shape and structural integrity. Each cytoskeletal network contributes its unique properties to dynamic cell behaviour, such as cell polarization, membrane protrusion, cell adhesion and contraction. Hence, cell migration requires the dynamic orchestration of all cytoskeleton components. Among these, IFs have emerged as a molecular scaffold with unique mechanical features and a key player in the cell resilience to mechanical stresses during migration through complex 3D environment. Moreover, accumulating evidence illustrates the participation of IFs in signalling cascades and cytoskeletal crosstalk. Teaming up with actin and microtubules, IFs contribute to the active generation of forces required for cell adhesion and mesenchymal migration and invasion. Here we summarize and discuss how IFs integrate mechanical properties and signalling functions to control cell migration in a wide spectrum of physiological and pathological situations.
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20
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Jones ML, Dahl KN, Lele TP, Conway DE, Shenoy V, Ghosh S, Szczesny SE. The Elephant in the Cell: Nuclear Mechanics and Mechanobiology. J Biomech Eng 2022; 144:1135613. [PMID: 35147160 PMCID: PMC8990742 DOI: 10.1115/1.4053797] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Indexed: 11/08/2022]
Abstract
The 2021 Summer Biomechanics, Bioengineering, and Biotransport Conference (SB3C) featured a workshop titled "The Elephant in the Room: Nuclear Mechanics and Mechanobiology." The goal of this workshop was to provide a perspective from experts in the field on the current understanding of nuclear mechanics and its role in mechanobiology. This paper reviews the major themes and questions discussed during the workshop, including historical context on the initial methods of measuring the mechanical properties of the nucleus and classifying the primary structures dictating nuclear mechanics, physical plasticity of the nucleus, the emerging role of the linker of nucleoskeleton and cytoskeleton (LINC) complex in coupling the nucleus to the cytoplasm and driving the behavior of individual cells and multicellular assemblies, and the computational models currently in use to investigate the mechanisms of gene expression and cell signaling. Ongoing questions and controversies, along with promising future directions, are also discussed.
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Affiliation(s)
- Michelle L Jones
- Clinical Insights, Ltd, 60 Summer Duck Way, Pittsburgh, PA 15238
| | - Kris Noel Dahl
- Department of Chemical Engineering, Carnegie Mellon University, Doherty Hall, 5000 Forbes Avenue, Pittsburgh, PA 15213; Forensics Department, Thornton Tomasetti, 120 Broadway 15th Floor, New York City, NY 10271
| | - Tanmay P Lele
- Department of Biomedical Engineering, Texas A&M University, 101 Bizzell Street, College Station, TX 77840; Department of Chemical Engineering, Texas A&M University, 101 Bizzell Street, College Station, TX 77840; Department of Translational Medical Sciences, Texas A&M University, 101 Bizzell Street, College Station, TX 77840
| | - Daniel E Conway
- Department of Biomedical Engineering, Virginia Commonwealth University, 601 West Main Street, P.O. Box 843068, Richmond, VA 23284
| | - Vivek Shenoy
- Materials Science and Engineering Bioengineering, University of Pennsylvania, 3231 Walnut Street, Philadelphia, PA 19104; Mechanical Engineering and Applied Mechanics, University of Pennsylvania, 3231 Walnut Street, Philadelphia, PA 19104; Center for Engineering Mechanobiology, University of Pennsylvania, 3231 Walnut Street, Philadelphia, PA 19104
| | - Soham Ghosh
- Department of Mechanical Engineering, School of Biomedical Engineering, Translational Medicine Institute, Colorado State University, 400 Isotope Drive, Fort Collins, CO 80521
| | - Spencer E Szczesny
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA 16802; Department of Orthopaedics and Rehabilitation, Pennsylvania State University, University Park, PA 16802
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21
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Shen Z, Lengyel M, Niethammer P. The yellow brick road to nuclear membrane mechanotransduction. APL Bioeng 2022; 6:021501. [PMID: 35382443 PMCID: PMC8967412 DOI: 10.1063/5.0080371] [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: 11/30/2021] [Accepted: 03/09/2022] [Indexed: 02/06/2023] Open
Abstract
The nuclear membrane may function as a mechanosensory surface alongside the plasma membrane. In this Review, we discuss how this idea emerged, where it currently stands, and point out possible implications, without any claim of comprehensiveness.
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Affiliation(s)
- Zhouyang Shen
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
- Gerstner Sloan Kettering Graduate School of Biomedical Sciences, New York, New York 10065, USA
| | - Miklós Lengyel
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Philipp Niethammer
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
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22
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Deviri D, Safran SA. Balance of osmotic pressures determines the nuclear-to-cytoplasmic volume ratio of the cell. Proc Natl Acad Sci U S A 2022; 119:e2118301119. [PMID: 35580183 PMCID: PMC9173802 DOI: 10.1073/pnas.2118301119] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 04/05/2022] [Indexed: 01/06/2023] Open
Abstract
The volume of the cell nucleus varies across cell types and species and is commonly thought to be determined by the size of the genome and degree of chromatin compaction. However, this notion has been challenged over the years by much experimental evidence. Here, we consider the physical condition of mechanical force balance as a determining condition of the nuclear volume and use quantitative, order-of-magnitude analysis to estimate the forces from different sources of nuclear and cytoplasmic pressure. Our estimates suggest that the dominant pressure within the nucleus and cytoplasm of nonstriated muscle cells originates from the osmotic pressure of proteins and RNA molecules that are localized to the nucleus or cytoplasm by out-of-equilibrium, active nucleocytoplasmic transport rather than from chromatin or its associated ions. This motivates us to formulate a physical model for the ratio of the cell and nuclear volumes in which osmotic pressures of localized proteins determine the relative volumes. In accordance with unexplained observations that are a century old, our model predicts that the ratio of the cell and nuclear volumes is a constant, robust to a wide variety of biochemical and biophysical manipulations, and is changed only if gene expression or nucleocytoplasmic transport is modulated.
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Affiliation(s)
- Dan Deviri
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovet 76100, Israel
| | - Samuel A. Safran
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovet 76100, Israel
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23
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Mechanobiology of Colorectal Cancer. Cancers (Basel) 2022; 14:cancers14081945. [PMID: 35454852 PMCID: PMC9028036 DOI: 10.3390/cancers14081945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/06/2022] [Accepted: 04/07/2022] [Indexed: 11/16/2022] Open
Abstract
Simple Summary It is well documented that colorectal cancer (CRC) is the third most common cancer type, responsible for high mortality in developed countries, resulting in a high socio-economic impact. Several biochemical and gene expression pathways explaining the manifestation of this cancer in humans have already been identified. However, explanations for some of the related biophysical mechanisms and their influence on CRC remain elusive. In CRC, biophysics and medical research have already revealed the importance of studying the effects of the stiffness and viscoelasticity of the substrate on cells, as well as the effect of the shear stress of blood and lymphatic vessels on the behavior of cells and tissues. A deeper understanding of the relationship between the biophysical cues and biochemical signals could be advantageous to develop new diagnostic techniques and therapeutic strategies. Being a disease with a high mortality rate, it becomes crucial to dedicate efforts to finding effective, alternative therapeutic strategies. Abstract In this review, the mechanobiology of colorectal cancer (CRC) are discussed. Mechanotransduction of CRC is addressed considering the relationship of several biophysical cues and biochemical pathways. Mechanobiology is focused on considering how it may influence epithelial cells in terms of motility, morphometric changes, intravasation, circulation, extravasation, and metastization in CRC development. The roles of the tumor microenvironment, ECM, and stroma are also discussed, taking into account the influence of alterations and surface modifications on mechanical properties and their impact on epithelial cells and CRC progression. The role of cancer-associated fibroblasts and the impact of flow shear stress is addressed in terms of how it affects CRC metastization. Finally, some insights concerning how the knowledge of biophysical mechanisms may contribute to the development of new therapeutic strategies and targeting molecules and how mechanical changes of the microenvironment play a role in CRC disease are presented.
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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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Mierke CT. Viscoelasticity, Like Forces, Plays a Role in Mechanotransduction. Front Cell Dev Biol 2022; 10:789841. [PMID: 35223831 PMCID: PMC8864183 DOI: 10.3389/fcell.2022.789841] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 01/11/2022] [Indexed: 12/13/2022] Open
Abstract
Viscoelasticity and its alteration in time and space has turned out to act as a key element in fundamental biological processes in living systems, such as morphogenesis and motility. Based on experimental and theoretical findings it can be proposed that viscoelasticity of cells, spheroids and tissues seems to be a collective characteristic that demands macromolecular, intracellular component and intercellular interactions. A major challenge is to couple the alterations in the macroscopic structural or material characteristics of cells, spheroids and tissues, such as cell and tissue phase transitions, to the microscopic interferences of their elements. Therefore, the biophysical technologies need to be improved, advanced and connected to classical biological assays. In this review, the viscoelastic nature of cytoskeletal, extracellular and cellular networks is presented and discussed. Viscoelasticity is conceptualized as a major contributor to cell migration and invasion and it is discussed whether it can serve as a biomarker for the cells’ migratory capacity in several biological contexts. It can be hypothesized that the statistical mechanics of intra- and extracellular networks may be applied in the future as a powerful tool to explore quantitatively the biomechanical foundation of viscoelasticity over a broad range of time and length scales. Finally, the importance of the cellular viscoelasticity is illustrated in identifying and characterizing multiple disorders, such as cancer, tissue injuries, acute or chronic inflammations or fibrotic diseases.
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Zhang C, Lü D, Zhang F, Wu Y, Zheng L, Zhang X, Li Z, Sun S, Long M. Gravity-Vector Induces Mechanical Remodeling of rMSCs via Combined Substrate Stiffness and Orientation. Front Bioeng Biotechnol 2022; 9:724101. [PMID: 35198547 PMCID: PMC8859489 DOI: 10.3389/fbioe.2021.724101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Accepted: 12/30/2021] [Indexed: 11/23/2022] Open
Abstract
Distinct physical factors originating from the cellular microenvironment are crucial to the biological homeostasis of stem cells. While substrate stiffness and orientation are known to regulate the mechanical remodeling and fate decision of mesenchymal stem cells (MSCs) separately, it remains unclear how the two factors are combined to manipulate their mechanical stability under gravity vector. Here we quantified these combined effects by placing rat MSCs onto stiffness-varied poly-dimethylsiloxane (PDMS) substrates in upward (180°), downward (0°), or edge-on (90°) orientation. Compared with those values onto glass coverslip, the nuclear longitudinal translocation, due to the density difference between the nucleus and the cytosol, was found to be lower at 0° for 24 h and higher at 90° for 24 and 72 h onto 2.5 MPa PDMS substrate. At 0°, the cell was mechanically supported by remarkably reduced actin and dramatically enhanced vimentin expression. At 90°, both enhanced actin and vimentin expression worked cooperatively to maintain cell stability. Specifically, perinuclear actin stress fibers with a large number, low anisotropy, and visible perinuclear vimentin cords were formed onto 2.5 MPa PDMS at 90° for 72 h, supporting the orientation difference in nuclear translocation and global cytoskeleton expression. This orientation dependence tended to disappear onto softer PDMS, presenting distinctive features in nuclear translocation and cytoskeletal structures. Moreover, cellular morphology and focal adhesion were mainly affected by substrate stiffness, yielding a time course of increased spreading area at 24 h but decreased area at 72 h with a decrease of stiffness. Mechanistically, the cell tended to be stabilized onto these PDMS substrates via β1 integrin–focal adhesion complexes–actin mechanosensitive axis. These results provided an insight in understanding the combination of substrate stiffness and orientation in defining the mechanical stability of rMSCs.
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Affiliation(s)
- Chen Zhang
- Center for Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory) and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China
| | - Dongyuan Lü
- Center for Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory) and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China
- School of Engineering Science, University of Chinese Academy of Sciences, Beijing, China
| | - Fan Zhang
- Center for Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory) and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China
- School of Engineering Science, University of Chinese Academy of Sciences, Beijing, China
| | - Yi Wu
- Center for Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory) and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China
- School of Engineering Science, University of Chinese Academy of Sciences, Beijing, China
| | - Lu Zheng
- Center for Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory) and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China
- School of Engineering Science, University of Chinese Academy of Sciences, Beijing, China
| | - Xiaoyu Zhang
- Center for Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory) and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China
- School of Engineering Science, University of Chinese Academy of Sciences, Beijing, China
| | - Zhan Li
- Center for Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory) and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China
| | - Shujin Sun
- Center for Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory) and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China
- School of Engineering Science, University of Chinese Academy of Sciences, Beijing, China
| | - Mian Long
- Center for Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory) and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China
- School of Engineering Science, University of Chinese Academy of Sciences, Beijing, China
- *Correspondence: Mian Long,
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Dickinson RB, Katiyar A, Dubell CR, Lele TP. Viscous shaping of the compliant cell nucleus. APL Bioeng 2022; 6:010901. [PMID: 35028490 PMCID: PMC8730821 DOI: 10.1063/5.0071652] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 12/01/2021] [Indexed: 01/08/2023] Open
Abstract
The cell nucleus is commonly considered to be a stiff organelle that mechanically resists changes in shape, and this resistance is thought to limit the ability of cells to migrate through pores or spread on surfaces. Generation of stresses on the cell nucleus during migration and nuclear response to these stresses is fundamental to cell migration and mechano-transduction. In this Perspective, we discuss our previous experimental and computational evidence that supports a dynamic model, in which the soft nucleus is irreversibly shaped by viscous stresses generated by the motion of cell boundaries and transmitted through the intervening cytoskeletal network. While the nucleus is commonly modeled as a stiff elastic body, we review how nuclear shape changes on the timescale of migration can be explained by simple geometric constraints of constant nuclear volume and constant surface area of the nuclear lamina. Because the lamina surface area is in excess of that of a sphere of the same volume, these constraints permit dynamic transitions between a wide range of shapes during spreading and migration. The excess surface area allows the nuclear shape changes to mirror those of the cell with little mechanical resistance. Thus, the nucleus can be easily shaped by the moving cell boundaries over a wide range of shape changes and only becomes stiff to more extreme deformations that would require the lamina to stretch or the volume to compress. This model explains how nuclei can easily flatten on surfaces during cell spreading or elongate as cells move through pores until the lamina smooths out and becomes tense.
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Affiliation(s)
- Richard B Dickinson
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, USA
| | - Aditya Katiyar
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas 77843, USA
| | - Christina R Dubell
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas 77843, USA
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Abstract
Cells generate and sense mechanical forces that trigger biochemical signals to elicit cellular responses that control cell fate changes. Mechanical forces also physically distort neighboring cells and the surrounding connective tissue, which propagate mechanochemical signals over long distances to guide tissue patterning, organogenesis, and adult tissue homeostasis. As the largest and stiffest organelle, the nucleus is particularly sensitive to mechanical force and deformation. Nuclear responses to mechanical force include adaptations in chromatin architecture and transcriptional activity that trigger changes in cell state. These force-driven changes also influence the mechanical properties of chromatin and nuclei themselves to prevent aberrant alterations in nuclear shape and help maintain genome integrity. This review will discuss principles of nuclear mechanotransduction and chromatin mechanics and their role in DNA damage and cell fate regulation.
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Affiliation(s)
- Yekaterina A Miroshnikova
- Helsinki Institute of Life Science, Biomedicum Helsinki, University of Helsinki, Helsinki 00014, Finland
- Wihuri Research Institute, Biomedicum Helsinki, University of Helsinki, Helsinki 00290, Finland
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki 00014, Finland
- Max Planck Institute for Biology of Ageing, Cologne 50931, Germany
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Sara A Wickström
- Helsinki Institute of Life Science, Biomedicum Helsinki, University of Helsinki, Helsinki 00014, Finland
- Wihuri Research Institute, Biomedicum Helsinki, University of Helsinki, Helsinki 00290, Finland
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki 00014, Finland
- Max Planck Institute for Biology of Ageing, Cologne 50931, Germany
- Cluster of Excellence Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne 50931, Germany
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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: 10] [Impact Index Per Article: 5.0] [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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Aguilera Suarez S, Sekar NC, Nguyen N, Lai A, Thurgood P, Zhou Y, Needham S, Pirogova E, Khoshmanesh K, Baratchi S. Studying the Mechanobiology of Aortic Endothelial Cells Under Cyclic Stretch Using a Modular 3D Printed System. Front Bioeng Biotechnol 2021; 9:791116. [PMID: 34957080 PMCID: PMC8698250 DOI: 10.3389/fbioe.2021.791116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 11/15/2021] [Indexed: 02/05/2023] Open
Abstract
Here, we describe a motorized cam-driven system for the cyclic stretch of aortic endothelial cells. Our modular design allows for generating customized spatiotemporal stretch profiles by varying the profile and size of 3D printed cam and follower elements. The system is controllable, compact, inexpensive, and amenable for parallelization and long-term experiments. Experiments using human aortic endothelial cells show significant changes in the cytoskeletal structure and morphology of cells following exposure to 5 and 10% cyclic stretch over 9 and 16 h. The system provides upportunities for exploring the complex molecular and cellular processes governing the response of mechanosensitive cells under cyclic stretch.
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Affiliation(s)
| | - Nadia Chandra Sekar
- School of Health and Biomedical Sciences, RMIT University, Melbourne, VIC, Australia
| | - Ngan Nguyen
- School of Engineering, RMIT University, Melbourne, VIC, Australia
| | - Austin Lai
- School of Health and Biomedical Sciences, RMIT University, Melbourne, VIC, Australia
| | - Peter Thurgood
- School of Engineering, RMIT University, Melbourne, VIC, Australia
| | - Ying Zhou
- School of Health and Biomedical Sciences, RMIT University, Melbourne, VIC, Australia
| | | | - Elena Pirogova
- School of Engineering, RMIT University, Melbourne, VIC, Australia
| | | | - Sara Baratchi
- School of Health and Biomedical Sciences, RMIT University, Melbourne, VIC, Australia
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Caragine CM, Kanellakopoulos N, Zidovska A. Mechanical stress affects dynamics and rheology of the human genome. SOFT MATTER 2021; 18:107-116. [PMID: 34874386 DOI: 10.1039/d1sm00983d] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Material properties of the genome are critical for proper cellular function - they directly affect timescales and length scales of DNA transactions such as transcription, replication and DNA repair, which in turn impact all cellular processes via the central dogma of molecular biology. Hence, elucidating the genome's rheology in vivo may help reveal physical principles underlying the genome's organization and function. Here, we present a novel noninvasive approach to study the genome's rheology and its response to mechanical stress in form of nuclear injection in live human cells. Specifically, we use Displacement Correlation Spectroscopy to map nucleus-wide genomic motions pre/post injection, during which we deposit rheological probes inside the cell nucleus. While the genomic motions inform on the bulk rheology of the genome pre/post injection, the probe's motion informs on the local rheology of its surroundings. Our results reveal that mechanical stress of injection leads to local as well as nucleus-wide changes in the genome's compaction, dynamics and rheology. We find that the genome pre-injection exhibits subdiffusive motions, which are coherent over several micrometers. In contrast, genomic motions post-injection become faster and uncorrelated, moreover, the genome becomes less compact and more viscous across the entire nucleus. In addition, we use the injected particles as rheological probes and find the genome to condense locally around them, mounting a local elastic response. Taken together, our results show that mechanical stress alters both dynamics and material properties of the genome. These changes are consistent with those observed upon DNA damage, suggesting that the genome experiences similar effects during the injection process.
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Affiliation(s)
- Christina M Caragine
- Center for Soft Matter Research, Department of Physics, New York University, New York, NY 10003, USA.
| | - Nikitas Kanellakopoulos
- Center for Soft Matter Research, Department of Physics, New York University, New York, NY 10003, USA.
| | - Alexandra Zidovska
- Center for Soft Matter Research, Department of Physics, New York University, New York, NY 10003, USA.
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Siemsen K, Rajput S, Rasch F, Taheri F, Adelung R, Lammerding J, Selhuber-Unkel C. Tunable 3D Hydrogel Microchannel Networks to Study Confined Mammalian Cell Migration. Adv Healthc Mater 2021; 10:e2100625. [PMID: 34668667 PMCID: PMC8743577 DOI: 10.1002/adhm.202100625] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 07/12/2021] [Indexed: 11/12/2022]
Abstract
Cells adapt and move due to chemical, physical, and mechanical cues from their microenvironment. It is therefore important to create materials that mimic human tissue physiology by surface chemistry, architecture, and dimensionality to control cells in biomedical settings. The impact of the environmental architecture is particularly relevant in the context of cancer cell metastasis, where cells migrate through small constrictions in their microenvironment to invade surrounding tissues. Here, a synthetic hydrogel scaffold with an interconnected, random, 3D microchannel network is presented that is functionalized with collagen to promote cell adhesion. It is shown that cancer cells can invade such scaffolds within days, and both the microarchitecture and stiffness of the hydrogel modulate cell invasion and nuclear dynamics of the cells. Specifically, it is found that cell migration through the microchannels is a function of hydrogel stiffness. In addition to this, it is shown that the hydrogel stiffness and confinement, influence the occurrence of nuclear envelope ruptures of cells. The tunable hydrogel microarchitecture and stiffness thus provide a novel tool to investigate cancer cell invasion as a function of the 3D microenvironment. Furthermore, the material provides a promising strategy to control cell positioning, migration, and cellular function in biological applications, such as tissue engineering.
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Affiliation(s)
- Katharina Siemsen
- Institute for Materials Science, Kiel University, Kiel, D-24143, Germany
| | - Sunil Rajput
- Institute for Molecular Systems Engineering (IMSE), Heidelberg University, Heidelberg, 69120, Germany
| | - Florian Rasch
- Institute for Materials Science, Kiel University, Kiel, D-24143, Germany
| | - Fereydoon Taheri
- Institute for Molecular Systems Engineering (IMSE), Heidelberg University, Heidelberg, 69120, Germany
| | - Rainer Adelung
- Institute for Materials Science, Kiel University, Kiel, D-24143, Germany
| | - Jan Lammerding
- Meinig School of Biomedical Engineering & Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Christine Selhuber-Unkel
- Institute for Molecular Systems Engineering (IMSE), Heidelberg University, Heidelberg, 69120, Germany
- Max Planck School Matter to Life, Jahnstraße 29, Heidelberg, 69120, Germany
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Hobson CM, Falvo MR, Superfine R. A survey of physical methods for studying nuclear mechanics and mechanobiology. APL Bioeng 2021; 5:041508. [PMID: 34849443 PMCID: PMC8604565 DOI: 10.1063/5.0068126] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 10/20/2021] [Indexed: 12/23/2022] Open
Abstract
It is increasingly appreciated that the cell nucleus is not only a home for DNA but also a complex material that resists physical deformations and dynamically responds to external mechanical cues. The molecules that confer mechanical properties to nuclei certainly contribute to laminopathies and possibly contribute to cellular mechanotransduction and physical processes in cancer such as metastasis. Studying nuclear mechanics and the downstream biochemical consequences or their modulation requires a suite of complex assays for applying, measuring, and visualizing mechanical forces across diverse length, time, and force scales. Here, we review the current methods in nuclear mechanics and mechanobiology, placing specific emphasis on each of their unique advantages and limitations. Furthermore, we explore important considerations in selecting a new methodology as are demonstrated by recent examples from the literature. We conclude by providing an outlook on the development of new methods and the judicious use of the current techniques for continued exploration into the role of nuclear mechanobiology.
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Affiliation(s)
| | - Michael R. Falvo
- Department of Physics and Astronomy, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Richard Superfine
- Department of Applied Physical Science, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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Iyer SR, Folker ES, Lovering RM. The Nucleoskeleton: Crossroad of Mechanotransduction in Skeletal Muscle. Front Physiol 2021; 12:724010. [PMID: 34721058 PMCID: PMC8554227 DOI: 10.3389/fphys.2021.724010] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 09/24/2021] [Indexed: 11/13/2022] Open
Abstract
Intermediate filaments (IFs) are a primary structural component of the cytoskeleton extending throughout the muscle cell (myofiber). Mechanotransduction, the process by which mechanical force is translated into a biochemical signal to activate downstream cellular responses, is crucial to myofiber function. Mechanical forces also act on the nuclear cytoskeleton, which is integrated with the myofiber cytoskeleton by the linker of the nucleoskeleton and cytoskeleton (LINC) complexes. Thus, the nucleus serves as the endpoint for the transmission of force through the cell. The nuclear lamina, a dense meshwork of lamin IFs between the nuclear envelope and underlying chromatin, plays a crucial role in responding to mechanical input; myofibers constantly respond to mechanical perturbation via signaling pathways by activation of specific genes. The nucleus is the largest organelle in cells and a master regulator of cell homeostasis, thus an understanding of how it responds to its mechanical environment is of great interest. The importance of the cell nucleus is magnified in skeletal muscle cells due to their syncytial nature and the extreme mechanical environment that muscle contraction creates. In this review, we summarize the bidirectional link between the organization of the nucleoskeleton and the contractile features of skeletal muscle as they relate to muscle function.
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Affiliation(s)
- Shama R Iyer
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Eric S Folker
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Richard M Lovering
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, United States.,Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, United States
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35
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Yeh CF, Chou C, Yang KC. Mechanotransduction in fibrosis: Mechanisms and treatment targets. CURRENT TOPICS IN MEMBRANES 2021; 87:279-314. [PMID: 34696888 DOI: 10.1016/bs.ctm.2021.07.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
Abstract
To perceive and integrate the environmental cues, cells and tissues sense and interpret various physical forces like shear, tensile, and compression stress. Mechanotransduction involves the sensing and translation of mechanical forces into biochemical and mechanical signals to guide cell fate and achieve tissue homeostasis. Disruption of this mechanical homeostasis by tissue injury elicits multiple cellular responses leading to pathological matrix deposition and tissue stiffening, and consequent evolution toward pro-inflammatory/pro-fibrotic phenotypes, leading to tissue/organ fibrosis. This review focuses on the molecular mechanisms linking mechanotransduction to fibrosis and uncovers the potential therapeutic targets to halt or resolve fibrosis.
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Affiliation(s)
- Chih-Fan Yeh
- Division of Cardiology, Department of Internal Medicine and Cardiovascular Center, National Taiwan University Hospital, Taipei, Taiwan; Department and Graduate Institute of Pharmacology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Caroline Chou
- Department and Graduate Institute of Pharmacology, National Taiwan University College of Medicine, Taipei, Taiwan; Washington University in St. Louis, St. Louis, MO, United States
| | - Kai-Chien Yang
- Division of Cardiology, Department of Internal Medicine and Cardiovascular Center, National Taiwan University Hospital, Taipei, Taiwan; Department and Graduate Institute of Pharmacology, National Taiwan University College of Medicine, Taipei, Taiwan; Research Center for Developmental Biology & Regenerative Medicine, National Taiwan University, Taipei, Taiwan; Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
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36
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Bend, Push, Stretch: Remarkable Structure and Mechanics of Single Intermediate Filaments and Meshworks. Cells 2021; 10:cells10081960. [PMID: 34440729 PMCID: PMC8394331 DOI: 10.3390/cells10081960] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 07/22/2021] [Accepted: 07/28/2021] [Indexed: 12/11/2022] Open
Abstract
The cytoskeleton of the eukaryotic cell provides a structural and functional scaffold enabling biochemical and cellular functions. While actin and microtubules form the main framework of the cell, intermediate filament networks provide unique mechanical properties that increase the resilience of both the cytoplasm and the nucleus, thereby maintaining cellular function while under mechanical pressure. Intermediate filaments (IFs) are imperative to a plethora of regulatory and signaling functions in mechanotransduction. Mutations in all types of IF proteins are known to affect the architectural integrity and function of cellular processes, leading to debilitating diseases. The basic building block of all IFs are elongated α-helical coiled-coils that assemble hierarchically into complex meshworks. A remarkable mechanical feature of IFs is the capability of coiled-coils to metamorphize into β-sheets under stress, making them one of the strongest and most resilient mechanical entities in nature. Here, we discuss structural and mechanical aspects of IFs with a focus on nuclear lamins and vimentin.
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Gould NR, Torre OM, Leser JM, Stains JP. The cytoskeleton and connected elements in bone cell mechano-transduction. Bone 2021; 149:115971. [PMID: 33892173 PMCID: PMC8217329 DOI: 10.1016/j.bone.2021.115971] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/30/2021] [Accepted: 04/17/2021] [Indexed: 02/07/2023]
Abstract
Bone is a mechano-responsive tissue that adapts to changes in its mechanical environment. Increases in strain lead to increased bone mass acquisition, whereas decreases in strain lead to a loss of bone mass. Given that mechanical stress is a regulator of bone mass and quality, it is important to understand how bone cells sense and transduce these mechanical cues into biological changes to identify druggable targets that can be exploited to restore bone cell mechano-sensitivity or to mimic mechanical load. Many studies have identified individual cytoskeletal components - microtubules, actin, and intermediate filaments - as mechano-sensors in bone. However, given the high interconnectedness and interaction between individual cytoskeletal components, and that they can assemble into multiple discreet cellular structures, it is likely that the cytoskeleton as a whole, rather than one specific component, is necessary for proper bone cell mechano-transduction. This review will examine the role of each cytoskeletal element in bone cell mechano-transduction and will present a unified view of how these elements interact and work together to create a mechano-sensor that is necessary to control bone formation following mechanical stress.
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Affiliation(s)
- Nicole R Gould
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Olivia M Torre
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Jenna M Leser
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Joseph P Stains
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA..
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38
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Balogh P, Gounley J, Roychowdhury S, Randles A. A data-driven approach to modeling cancer cell mechanics during microcirculatory transport. Sci Rep 2021; 11:15232. [PMID: 34315934 PMCID: PMC8316468 DOI: 10.1038/s41598-021-94445-5] [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: 04/12/2021] [Accepted: 07/09/2021] [Indexed: 02/07/2023] Open
Abstract
In order to understand the effect of cellular level features on the transport of circulating cancer cells in the microcirculation, there has been an increasing reliance on high-resolution in silico models. Accurate simulation of cancer cells flowing with blood cells requires resolving cellular-scale interactions in 3D, which is a significant computational undertaking warranting a cancer cell model that is both computationally efficient yet sufficiently complex to capture relevant behavior. Given that the characteristics of metastatic spread are known to depend on cancer type, it is crucial to account for mechanistic behavior representative of a specific cancer's cells. To address this gap, in the present work we develop and validate a means by which an efficient and popular membrane model-based approach can be used to simulate deformable cancer cells and reproduce experimental data from specific cell lines. Here, cells are modeled using the immersed boundary method (IBM) within a lattice Boltzmann method (LBM) fluid solver, and the finite element method (FEM) is used to model cell membrane resistance to deformation. Through detailed comparisons with experiments, we (i) validate this model to represent cancer cells undergoing large deformation, (ii) outline a systematic approach to parameterize different cell lines to optimally fit experimental data over a range of deformations, and (iii) provide new insight into nucleated vs. non-nucleated cell models and their ability to match experiments. While many works have used the membrane-model based method employed here to model generic cancer cells, no quantitative comparisons with experiments exist in the literature for specific cell lines undergoing large deformation. Here, we describe a phenomenological, data-driven approach that can not only yield good agreement for large deformations, but explicitly detail how it can be used to represent different cancer cell lines. This model is readily incorporated into cell-resolved hemodynamic transport simulations, and thus offers significant potential to complement experiments towards providing new insights into various aspects of cancer progression.
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Affiliation(s)
- Peter Balogh
- grid.26009.3d0000 0004 1936 7961Department of Biomedical Engineering, Duke University, Durham, NC USA
| | - John Gounley
- grid.135519.a0000 0004 0446 2659Computational Sciences and Engineering, Oak Ridge National Laboratory, Oak Ridge, TN USA
| | - Sayan Roychowdhury
- grid.26009.3d0000 0004 1936 7961Department of Biomedical Engineering, Duke University, Durham, NC USA
| | - Amanda Randles
- grid.26009.3d0000 0004 1936 7961Department of Biomedical Engineering, Duke University, Durham, NC USA
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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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40
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Nuclear Organization during Hepatogenesis in Zebrafish Requires Uhrf1. Genes (Basel) 2021; 12:genes12071081. [PMID: 34356097 PMCID: PMC8304062 DOI: 10.3390/genes12071081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 07/08/2021] [Accepted: 07/12/2021] [Indexed: 01/07/2023] Open
Abstract
Acquisition of cellular fate during development is initiated and maintained by well-coordinated patterns of gene expression that are dictated by the epigenetic landscape and genome organization in the nucleus. While the epigenetic marks that mediate developmental gene expression patterns during organogenesis have been well studied, less is known about how epigenetic marks influence nuclear organization during development. This study examines the relationship between nuclear structure, chromatin accessibility, DNA methylation, and gene expression during hepatic outgrowth in zebrafish larvae. We investigate the relationship between these features using mutants that lack DNA methylation. Hepatocyte nuclear morphology was established coincident with hepatocyte differentiation at 80 h post-fertilization (hpf), and nuclear shape and size continued to change until the conclusion of outgrowth and morphogenesis at 120 hpf. Integrating ATAC-Seq analysis with DNA methylation profiling of zebrafish livers at 120 hpf showed that closed and highly methylated chromatin occupies most transposable elements and that open chromatin correlated with gene expression. DNA hypomethylation, due to mutation of genes encoding ubiquitin-like, containing PHD and RING Finger Domains 1 (uhrf1) and DNA methyltransferase (dnmt1), did not block hepatocyte differentiation, but had dramatic effects on nuclear organization. Hepatocytes in uhrf1 mutants have large, deformed nuclei with multiple nucleoli, downregulation of nucleolar genes, and a complete lack of the nuclear lamina. Loss of lamin B2 staining was phenocopied by dnmt1 mutation. Together, these data show that hepatocyte nuclear morphogenesis coincides with organ morphogenesis and outgrowth, and that DNA methylation directs chromatin organization, and, in turn, hepatocyte nuclear shape and size during liver development.
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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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42
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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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43
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Danielsson BE, Tieu KV, Bathula K, Armiger TJ, Vellala PS, Taylor RE, Dahl KN, Conway DE. Lamin microaggregates lead to altered mechanotransmission in progerin-expressing cells. Nucleus 2021; 11:194-204. [PMID: 32816594 PMCID: PMC7529416 DOI: 10.1080/19491034.2020.1802906] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The nuclear lamina is a meshwork of intermediate filament proteins, and lamin A is the primary mechanical protein. An altered splicing of lamin A, known as progerin, causes the disease Hutchinson-Gilford progeria syndrome. Progerin-expressing cells have altered nuclear shapes and stiffened nuclear lamina with microaggregates of progerin. Here, progerin microaggregate inclusions in the lamina are shown to lead to cellular and multicellular dysfunction. We show with Comsol simulations that stiffened inclusions causes redistribution of normally homogeneous forces, and this redistribution is dependent on the stiffness difference and relatively independent of inclusion size. We also show mechanotransmission changes associated with progerin expression in cells under confinement and cells under external forces. Endothelial cells expressing progerin do not align properly with patterning. Fibroblasts expressing progerin do not align properly to applied cyclic force. Combined, these studies show that altered nuclear lamina mechanics and microstructure impacts cytoskeletal force transmission through the cell.
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Affiliation(s)
- Brooke E Danielsson
- Department of Biomedical Engineering, Virginia Commonwealth University , Richmond, VA, USA
| | - Katie V Tieu
- Department of Biomedical Engineering, Virginia Commonwealth University , Richmond, VA, USA
| | - Kranthidhar Bathula
- Department of Biomedical Engineering, Virginia Commonwealth University , Richmond, VA, USA
| | - Travis J Armiger
- Chemical Engineering, Carnegie Mellon University , Pittsburgh, PA, USA
| | - Pragna S Vellala
- Department of Biomedical Engineering, Carnegie Mellon University , Pittsburgh, PA , USA
| | - Rebecca E Taylor
- Department of Biomedical Engineering, Carnegie Mellon University , Pittsburgh, PA , USA.,Department of Mechanical Engineering, Carnegie Mellon University , Pittsburgh, PA, USA
| | - Kris Noel Dahl
- Chemical Engineering, Carnegie Mellon University , Pittsburgh, PA, USA.,Department of Biomedical Engineering, Carnegie Mellon University , Pittsburgh, PA , USA
| | - Daniel E Conway
- Department of Biomedical Engineering, Virginia Commonwealth University , Richmond, VA, USA
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44
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Vasilaki D, Bakopoulou A, Tsouknidas A, Johnstone E, Michalakis K. Biophysical interactions between components of the tumor microenvironment promote metastasis. Biophys Rev 2021; 13:339-357. [PMID: 34168685 PMCID: PMC8214652 DOI: 10.1007/s12551-021-00811-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Accepted: 05/03/2021] [Indexed: 02/07/2023] Open
Abstract
During metastasis, tumor cells need to adapt to their dynamic microenvironment and modify their mechanical properties in response to both chemical and mechanical stimulation. Physical interactions occur between cancer cells and the surrounding matrix including cell movements and cell shape alterations through the process of mechanotransduction. The latter describes the translation of external mechanical cues into intracellular biochemical signaling. Reorganization of both the cytoskeleton and the extracellular matrix (ECM) plays a critical role in these spreading steps. Migrating tumor cells show increased motility in order to cross the tumor microenvironment, migrate through ECM and reach the bloodstream to the metastatic site. There are specific factors affecting these processes, as well as the survival of circulating tumor cells (CTC) in the blood flow until they finally invade the secondary tissue to form metastasis. This review aims to study the mechanisms of metastasis from a biomechanical perspective and investigate cell migration, with a focus on the alterations in the cytoskeleton through this journey and the effect of biologic fluids on metastasis. Understanding of the biophysical mechanisms that promote tumor metastasis may contribute successful therapeutic approaches in the fight against cancer.
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Affiliation(s)
- Dimitra Vasilaki
- Department of Prosthodontics, School of Dentistry, Faculty of Health Sciences, Aristotle University of Thessaloniki, University Campus, 54124 Thessaloniki, Greece
| | - Athina Bakopoulou
- Department of Prosthodontics, School of Dentistry, Faculty of Health Sciences, Aristotle University of Thessaloniki, University Campus, 54124 Thessaloniki, Greece
| | - Alexandros Tsouknidas
- Laboratory for Biomaterials and Computational Mechanics, Department of Mechanical Engineering, University of Western Macedonia, Kozani, Greece
| | | | - Konstantinos Michalakis
- Department of Prosthodontics, School of Dentistry, Faculty of Health Sciences, Aristotle University of Thessaloniki, University Campus, 54124 Thessaloniki, Greece
- Division of Graduate Prosthodontics, Tufts University School of Dental Medicine, Boston, MA USA
- University of Oxford, Oxford, UK
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45
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Dieterle MP, Husari A, Steinberg T, Wang X, Ramminger I, Tomakidi P. From the Matrix to the Nucleus and Back: Mechanobiology in the Light of Health, Pathologies, and Regeneration of Oral Periodontal Tissues. Biomolecules 2021; 11:824. [PMID: 34073044 PMCID: PMC8228498 DOI: 10.3390/biom11060824] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/25/2021] [Accepted: 05/27/2021] [Indexed: 02/07/2023] Open
Abstract
Among oral tissues, the periodontium is permanently subjected to mechanical forces resulting from chewing, mastication, or orthodontic appliances. Molecularly, these movements induce a series of subsequent signaling processes, which are embedded in the biological concept of cellular mechanotransduction (MT). Cell and tissue structures, ranging from the extracellular matrix (ECM) to the plasma membrane, the cytosol and the nucleus, are involved in MT. Dysregulation of the diverse, fine-tuned interaction of molecular players responsible for transmitting biophysical environmental information into the cell's inner milieu can lead to and promote serious diseases, such as periodontitis or oral squamous cell carcinoma (OSCC). Therefore, periodontal integrity and regeneration is highly dependent on the proper integration and regulation of mechanobiological signals in the context of cell behavior. Recent experimental findings have increased the understanding of classical cellular mechanosensing mechanisms by both integrating exogenic factors such as bacterial gingipain proteases and newly discovered cell-inherent functions of mechanoresponsive co-transcriptional regulators such as the Yes-associated protein 1 (YAP1) or the nuclear cytoskeleton. Regarding periodontal MT research, this review offers insights into the current trends and open aspects. Concerning oral regenerative medicine or weakening of periodontal tissue diseases, perspectives on future applications of mechanobiological principles are discussed.
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Affiliation(s)
- Martin Philipp Dieterle
- Center for Dental Medicine, Division of Oral Biotechnology, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, Hugstetterstr. 55, 79106 Freiburg, Germany; (M.P.D.); (X.W.); (I.R.); (P.T.)
| | - Ayman Husari
- Center for Dental Medicine, Department of Orthodontics, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, Hugstetterstr. 55, 79106 Freiburg, Germany;
- Faculty of Engineering, University of Freiburg, Georges-Köhler-Allee 101, 79110 Freiburg, Germany
| | - Thorsten Steinberg
- Center for Dental Medicine, Division of Oral Biotechnology, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, Hugstetterstr. 55, 79106 Freiburg, Germany; (M.P.D.); (X.W.); (I.R.); (P.T.)
| | - Xiaoling Wang
- Center for Dental Medicine, Division of Oral Biotechnology, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, Hugstetterstr. 55, 79106 Freiburg, Germany; (M.P.D.); (X.W.); (I.R.); (P.T.)
| | - Imke Ramminger
- Center for Dental Medicine, Division of Oral Biotechnology, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, Hugstetterstr. 55, 79106 Freiburg, Germany; (M.P.D.); (X.W.); (I.R.); (P.T.)
| | - Pascal Tomakidi
- Center for Dental Medicine, Division of Oral Biotechnology, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, Hugstetterstr. 55, 79106 Freiburg, Germany; (M.P.D.); (X.W.); (I.R.); (P.T.)
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46
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Khalaf K, Hana D, Chou JTT, Singh C, Mackiewicz A, Kaczmarek M. Aspects of the Tumor Microenvironment Involved in Immune Resistance and Drug Resistance. Front Immunol 2021; 12:656364. [PMID: 34122412 PMCID: PMC8190405 DOI: 10.3389/fimmu.2021.656364] [Citation(s) in RCA: 175] [Impact Index Per Article: 58.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 04/27/2021] [Indexed: 12/11/2022] Open
Abstract
The tumor microenvironment (TME) is a complex and ever-changing "rogue organ" composed of its own blood supply, lymphatic and nervous systems, stroma, immune cells and extracellular matrix (ECM). These complex components, utilizing both benign and malignant cells, nurture the harsh, immunosuppressive and nutrient-deficient environment necessary for tumor cell growth, proliferation and phenotypic flexibility and variation. An important aspect of the TME is cellular crosstalk and cell-to-ECM communication. This interaction induces the release of soluble factors responsible for immune evasion and ECM remodeling, which further contribute to therapy resistance. Other aspects are the presence of exosomes contributed by both malignant and benign cells, circulating deregulated microRNAs and TME-specific metabolic patterns which further potentiate the progression and/or resistance to therapy. In addition to biochemical signaling, specific TME characteristics such as the hypoxic environment, metabolic derangements, and abnormal mechanical forces have been implicated in the development of treatment resistance. In this review, we will provide an overview of tumor microenvironmental composition, structure, and features that influence immune suppression and contribute to treatment resistance.
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Affiliation(s)
- Khalil Khalaf
- Department of Cancer Diagnostics and Immunology, Greater Poland Cancer Center, Poznań, Poland
- Department of Cancer Immunology, Poznan University of Medical Sciences, Poznań, Poland
| | - Doris Hana
- Department of Cancer Diagnostics and Immunology, Greater Poland Cancer Center, Poznań, Poland
- Department of Cancer Immunology, Poznan University of Medical Sciences, Poznań, Poland
| | - Jadzia Tin-Tsen Chou
- Department of Cancer Diagnostics and Immunology, Greater Poland Cancer Center, Poznań, Poland
- Department of Cancer Immunology, Poznan University of Medical Sciences, Poznań, Poland
| | - Chandpreet Singh
- Department of Cancer Diagnostics and Immunology, Greater Poland Cancer Center, Poznań, Poland
- Department of Cancer Immunology, Poznan University of Medical Sciences, Poznań, Poland
| | - Andrzej Mackiewicz
- Department of Cancer Diagnostics and Immunology, Greater Poland Cancer Center, Poznań, Poland
- Department of Cancer Immunology, Poznan University of Medical Sciences, Poznań, Poland
| | - Mariusz Kaczmarek
- Department of Cancer Diagnostics and Immunology, Greater Poland Cancer Center, Poznań, Poland
- Department of Cancer Immunology, Poznan University of Medical Sciences, Poznań, Poland
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47
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Age-dependent changes in nuclear-cytoplasmic signaling in skeletal muscle. Exp Gerontol 2021; 150:111338. [PMID: 33862137 DOI: 10.1016/j.exger.2021.111338] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 03/28/2021] [Accepted: 04/03/2021] [Indexed: 02/07/2023]
Abstract
Mechanical forces are conducted through myofibers and into nuclei to regulate muscle development, hypertrophy, and homeostasis. We hypothesized that nuclei in aged muscle have changes in the nuclear envelope and associated proteins, resulting in altered markers of mechano-signaling. METHODS YAP/TAZ protein expression and gene expression of downstream targets, Ankrd1 and Cyr61, were evaluated as mechanotransduction indicators. Expression of proteins in the nuclear lamina and the nuclear pore complex (NPC) were assessed, and nuclear morphology was characterized by electron microscopy. Nuclear envelope permeability was assessed by uptake of 70 kDa fluorescent dextran. RESULTS Nuclear changes with aging included a relative decrease of lamin β1 and Nup107, and a relative increase in Nup93, which could underlie the aberrant nuclear morphology, increased nuclear leakiness, and elevated YAP/TAZ signaling. CONCLUSION Aged muscles have hyperactive nuclear-cytoplasmic signaling, indicative of altered nuclear mechanotransduction. These data highlight a possible role for the nucleus in aging-related aberrant mechano-sensing.
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48
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Cell stretchers and the LINC complex in mechanotransduction. Arch Biochem Biophys 2021; 702:108829. [PMID: 33716002 DOI: 10.1016/j.abb.2021.108829] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 02/23/2021] [Accepted: 03/07/2021] [Indexed: 02/07/2023]
Abstract
How cells respond to mechanical forces from the surrounding environment is critical for cell survival and function. The LINC complex is a central component in the mechanotransduction pathway that transmits mechanical information from the cell surface to the nucleus. Through LINC complex functionality, the nucleus is able to respond to mechanical stress by altering nuclear structure, chromatin organization, and gene expression. The use of specialized devices that apply mechanical strain to cells have been central to investigating how mechanotransduction occurs, how cells respond to mechanical stress, and the role of the LINC complexes in these processes. A large variety of designs have been reported for these devices, with the most common type being cell stretchers. Here we highlight some of the salient features of cell stretchers and suggest some key parameters that should be considered when using these devices. We provide a brief overview of how the LINC complexes contribute to the cellular responses to mechanical strain. And finally, we suggest that stretchers may be a useful tool to study aging.
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49
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Moradi M, Nazockdast E. Cell nucleus as a microrheological probe to study the rheology of the cytoskeleton. Biophys J 2021; 120:1542-1564. [PMID: 33705756 DOI: 10.1016/j.bpj.2021.01.042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 12/29/2020] [Accepted: 01/11/2021] [Indexed: 01/12/2023] Open
Abstract
Mechanical properties of the cell are important biomarkers for probing its architectural changes caused by cellular processes and/or pathologies. The development of microfluidic technologies has enabled measuring the cell's mechanical properties at high throughput so that mechanical phenotyping can be applied to large samples in reasonable timescales. These studies typically measure the stiffness of the cell as the only mechanical biomarker and do not disentangle the rheological contributions of different structural components of the cell, including the cell cortex, the interior cytoplasm and its immersed cytoskeletal structures, and the nucleus. Recent advancements in high-speed fluorescent imaging have enabled probing the deformations of the cell cortex while also tracking different intracellular components in rates applicable to microfluidic platforms. We present a, to our knowledge, novel method to decouple the mechanics of the cell cortex and the cytoplasm by analyzing the correlation between the cortical deformations that are induced by external microfluidic flows and the nucleus displacements, induced by those cortical deformations, i.e., we use the nucleus as a high-throughput microrheological probe to study the rheology of the cytoplasm, independent of the cell cortex mechanics. To demonstrate the applicability of this method, we consider a proof-of-concept model consisting of a rigid spherical nucleus centered in a spherical cell. We obtain analytical expressions for the time-dependent nucleus velocity as a function of the cell deformations when the interior cytoplasm is modeled as a viscous, viscoelastic, porous, and poroelastic material and demonstrate how the nucleus velocity can be used to characterize the linear rheology of the cytoplasm over a wide range of forces and timescales/frequencies.
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Affiliation(s)
- Moslem Moradi
- UNC Chapel Hill, Applied Physical Sciences, Chapel Hill, North Carolina
| | - Ehssan Nazockdast
- UNC Chapel Hill, Applied Physical Sciences, Chapel Hill, North Carolina.
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50
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Volkening K, Farhan SMK, Kao J, Leystra-Lantz C, Ang LC, McIntyre A, Wang J, Hegele RA, Strong MJ. Evidence of synergism among three genetic variants in a patient with LMNA-related lipodystrophy and amyotrophic lateral sclerosis leading to a remarkable nuclear phenotype. Mol Cell Biochem 2021; 476:2633-2650. [PMID: 33661429 PMCID: PMC8192393 DOI: 10.1007/s11010-021-04103-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Accepted: 02/06/2021] [Indexed: 11/25/2022]
Abstract
Neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), can be clinically heterogeneous which may be explained by the co-inheritance of multiple genetic variants that modify the clinical course. In this study we examine variants in three genes in a family with one individual presenting with ALS and lipodystrophy. Sequencing revealed a p.Gly602Ser variant in LMNA, and two additional variants, one each in SETX (g.intron10-13delCTT) and FUS (p.Gly167_Gly168del). These latter genes have been linked to ALS. All family members were genotyped and each variant, and each combination of variants detected, were functionally evaluated in vitro regarding effects on cell survival, expression patterns and cellular phenotype. Muscle biopsy retrieved from the individual with ALS showed leakage of chromatin from the nucleus, a phenotype that was recapitulated in vitro with expression of all three variants simultaneously. Individually expressed variants gave cellular phenotypes there were unremarkable. Interestingly the FUS variant appears to be protective against the effects of the SETX and the LMNA variants on cell viability and may indicate loss of interaction of FUS with SETX and/or R-loops. We conclude that these findings support genetic modifications as an explanation of the clinical heterogeneity observed in human disease.
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Affiliation(s)
- Kathryn Volkening
- Molecular Medicine, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Sali M K Farhan
- Analytic and Translational Genetics Unit, Center for Genomic Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02114, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| | - Jessica Kao
- Molecular Medicine, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Cheryl Leystra-Lantz
- Molecular Medicine, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Lee Cyn Ang
- Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- Department of Pathology and Laboratory Medicine, London Health Sciences Centre-University Hospital, London, ON, Canada
| | - Adam McIntyre
- Blackburn Cardiovascular Genetics Lab, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Jian Wang
- Blackburn Cardiovascular Genetics Lab, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Robert A Hegele
- Department of Pathology and Laboratory Medicine, London Health Sciences Centre-University Hospital, London, ON, Canada
- Blackburn Cardiovascular Genetics Lab, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- Department of Biochemistry, Western University, London, ON, Canada
| | - Michael J Strong
- Molecular Medicine, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.
- Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.
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