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Wang Y, Han X, Deng L, Wang X. Tunneling nanotube-transmitted mechanical signal and its cellular response. Biochem Biophys Res Commun 2024; 693:149368. [PMID: 38091838 DOI: 10.1016/j.bbrc.2023.149368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 12/05/2023] [Indexed: 01/10/2024]
Abstract
Tunneling nanotubes (TNTs) are elastic tubular structures that physically link cells, facilitating the intercellular transfer of organelles, chemical signals, and electrical signals. Despite TNTs serving as a multifunctional pathway for cell-cell communication, the transmission of mechanical signals through TNTs and the response of TNT-connected cells to these forces remain unexplored. In this study, external mechanical forces were applied to induce TNT bending between rat kidney (NRK) cells using micromanipulation. These forces, transmitted via TNTs, induced reduced curvature of the actin cortex and increased membrane tension at the TNT-connected sites. Additionally, TNT bending results in an elevation of intracellular calcium levels in TNT-connected cells, a response attenuated by gadolinium ions, a non-selective mechanosensitive calcium channel blocker. The degree of TNT deflection positively correlated with decreased actin cortex curvature and increased calcium levels. Furthermore, stretching TNT due to the separation of TNT-connected cells resulted in decreased actin cortex curvature and increased intracellular calcium in TNT-connected cells. The levels of these cellular responses depended on the length changes of TNTs. Moreover, TNT connections influence cell migration by regulating cell rotation, which involves the activation of mechanosensitive calcium channels. In conclusion, our study revealed the transmission of mechanical signals through TNTs and the subsequent responses of TNT-connected cells, highlighting a previously unrecognized communication function of TNTs. This research provides valuable insights into the role of TNTs in long-distance intercellular mechanical signaling.
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Affiliation(s)
- Yan Wang
- Institute of Biomedical Engineering and Health Sciences, Changzhou, Jiangsu, China; School of Pharmacy, Changzhou University, Changzhou, Jiangsu, China
| | - Xiaoning Han
- Institute of Biomedical Engineering and Health Sciences, Changzhou, Jiangsu, China; School of Medical and Health Engineering, Changzhou, Jiangsu, China
| | - Linhong Deng
- Institute of Biomedical Engineering and Health Sciences, Changzhou, Jiangsu, China; School of Medical and Health Engineering, Changzhou, Jiangsu, China.
| | - Xiang Wang
- Institute of Biomedical Engineering and Health Sciences, Changzhou, Jiangsu, China; School of Medical and Health Engineering, Changzhou, Jiangsu, China.
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2
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Tam R, Harris TJC. Reshaping the Syncytial Drosophila Embryo with Cortical Actin Networks: Four Main Steps of Early Development. Results Probl Cell Differ 2024; 71:67-90. [PMID: 37996673 DOI: 10.1007/978-3-031-37936-9_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2023]
Abstract
Drosophila development begins as a syncytium. The large size of the one-cell embryo makes it ideal for studying the structure, regulation, and effects of the cortical actin cytoskeleton. We review four main steps of early development that depend on the actin cortex. At each step, dynamic remodelling of the cortex has specific effects on nuclei within the syncytium. During axial expansion, a cortical actomyosin network assembles and disassembles with the cell cycle, generating cytoplasmic flows that evenly distribute nuclei along the ovoid cell. When nuclei move to the cell periphery, they seed Arp2/3-based actin caps which grow into an array of dome-like compartments that house the nuclei as they divide at the cell cortex. To separate germline nuclei from the soma, posterior germ plasm induces full cleavage of mono-nucleated primordial germ cells from the syncytium. Finally, zygotic gene expression triggers formation of the blastoderm epithelium via cellularization and simultaneous division of ~6000 mono-nucleated cells from a single internal yolk cell. During these steps, the cortex is regulated in space and time, gains domain and sub-domain structure, and undergoes mesoscale interactions that lay a structural foundation of animal development.
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Affiliation(s)
- Rebecca Tam
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Tony J C Harris
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON, Canada.
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Huang W, Ma Y, Tottori N, Yamanishi Y. Enhancing suspended cell transfection by inducing localized distribution of the membrane actin cortex before exposure to electromechanical stimulation. Biotechnol Lett 2023; 45:1417-1430. [PMID: 37656264 DOI: 10.1007/s10529-023-03382-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 03/07/2023] [Accepted: 04/11/2023] [Indexed: 09/02/2023]
Abstract
OBJECTIVES During physical transfection, an electrical field or mechanical force is used to induce cell transfection. We tested if the disruption of a dense actin layer underneath the membrane of a suspended cell enhances cell transfection. RESULTS A bubble generator was used to electromechanically stimulate suspended cells. To clarify the influence of the actin layer (the actin cortex) on cell transfection efficiency, we used an actin polymerization inhibitor (cytochalasin D) to disrupt the actin cortex before electromechanical stimulation. Without cytochalasin D treatment, signals from the overall actin cortex decreased after electromechanical stimulation. With cytochalasin D treatment, there was localized F-actin aggregation under static conditions. After electromechanical stimulation, there was a partial loss (localized disruption), but no overall disruption, of the actin cortex. With the pretreatment with cytochalasin D, the transfection efficiency of plasmids (4.7, 8.3, or 11 kbp) into NIH/3T3 or UMR-106 cells increased significantly after exposure to electromechanical stimulation. CONCLUSIONS Localized distribution of the actin cortex before exposure to electromechanical stimulation is crucial for inducing a partial loss of the cortex, which improves transfection efficiency and large plasmid delivery.
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Affiliation(s)
- Wenjing Huang
- Department of Mechanical Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
- Information and control systems course, Kindai University technical college, 7-1, Kasugaoka, Nabari City, Mie Prefecture, 518-0459, Japan
| | - Yibo Ma
- Department of Mechanical Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Naotomo Tottori
- Department of Mechanical Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Yoko Yamanishi
- Department of Mechanical Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan.
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Lüchtefeld I, Bartolozzi A, Mejía Morales J, Dobre O, Basso M, Zambelli T, Vassalli M. Elasticity spectra as a tool to investigate actin cortex mechanics. J Nanobiotechnology 2020; 18:147. [PMID: 33081777 PMCID: PMC7576730 DOI: 10.1186/s12951-020-00706-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 10/09/2020] [Indexed: 12/24/2022] Open
Abstract
Background The mechanical properties of single living cells have proven to be a powerful marker of the cell physiological state. The use of nanoindentation-based single cell force spectroscopy provided a wealth of information on the elasticity of cells, which is still largely to be exploited. The simplest model to describe cell mechanics is to treat them as a homogeneous elastic material and describe it in terms of the Young’s modulus. Beside its simplicity, this approach proved to be extremely informative, allowing to assess the potential of this physical indicator towards high throughput phenotyping in diagnostic and prognostic applications. Results Here we propose an extension of this analysis to explicitly account for the properties of the actin cortex. We present a method, the Elasticity Spectra, to calculate the apparent stiffness of the cell as a function of the indentation depth and we suggest a simple phenomenological approach to measure the thickness and stiffness of the actin cortex, in addition to the standard Young’s modulus. Conclusions The Elasticity Spectra approach is tested and validated on a set of cells treated with cytoskeleton-affecting drugs, showing the potential to extend the current representation of cell mechanics, without introducing a detailed and complex description of the intracellular structure.![]()
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Affiliation(s)
- Ines Lüchtefeld
- Laboratory of Biosensors and Bioelectronics, ETH Zürich, Gloriastrasse 35, 8092, Zürich, Switzerland
| | - Alice Bartolozzi
- Dipartimento di Ingegneria dell'Informazione, Università degli studi di Firenze, Via di S. Marta 3, 50139, Firenze, Italy
| | - Julián Mejía Morales
- Institut de Physique de Nice, Université Côte d'Azur, 1361 Route des Lucioles, 06560, Valbonne, France.,Dipartimento di Medicina Sperimentale, Università degli studi di Genova, Via Leon Battista Alberti 2, 16132, Genova, Italy
| | - Oana Dobre
- James Watt School of Engineering, University of Glasgow, Oakfield avenue, Glasgow, G12 8LT, UK
| | - Michele Basso
- Dipartimento di Ingegneria dell'Informazione, Università degli studi di Firenze, Via di S. Marta 3, 50139, Firenze, Italy
| | - Tomaso Zambelli
- Laboratory of Biosensors and Bioelectronics, ETH Zürich, Gloriastrasse 35, 8092, Zürich, Switzerland
| | - Massimo Vassalli
- James Watt School of Engineering, University of Glasgow, Oakfield avenue, Glasgow, G12 8LT, UK.
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Sharma A, Dagar S, Mylavarapu SVS. Transgelin-2 and phosphoregulation of the LIC2 subunit of dynein govern mitotic spindle orientation. J Cell Sci 2020; 133:jcs239673. [PMID: 32467330 DOI: 10.1242/jcs.239673] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Accepted: 04/29/2020] [Indexed: 08/31/2023] Open
Abstract
The molecular motor dynein is essential for mitotic spindle orientation, which defines the axis of cell division. The light intermediate chain subunits, LIC1 and LIC2, define biochemically and functionally distinct vertebrate dynein complexes, with LIC2-dynein playing a crucial role in ensuring spindle orientation. We reveal a novel, mitosis-specific interaction of LIC2-dynein with the cortical actin-bundling protein transgelin-2. Transgelin-2 is required for maintaining proper spindle length, equatorial metaphase chromosome alignment, spindle orientation and timely anaphase onset. We show that transgelin-2 stabilizes the cortical recruitment of LGN-NuMA, which together with dynein is required for spindle orientation. The opposing actions of transgelin-2 and LIC2-dynein maintain optimal cortical levels of LGN-NuMA. In addition, we show that the highly conserved serine 194 phosphorylation of LIC2 is required for proper spindle orientation, by maintaining mitotic centrosome integrity to ensure optimal astral microtubule nucleation. The work reveals two specific mechanisms through which LIC2-dynein regulates mitotic spindle orientation; namely, through a new interactor transgelin-2, which is required for engagement of LGN-NuMA with the actin cortex, and through mitotic phosphoregulation of LIC2 to control microtubule nucleation from the poles.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Amit Sharma
- Laboratory of Cellular Dynamics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone Faridabad-Gurgaon Expressway, Faridabad, Haryana 121001, India
- Affiliated to the Manipal Academy of Higher Education, Manipal, Karnataka 576104, India
| | - Sunayana Dagar
- Laboratory of Cellular Dynamics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone Faridabad-Gurgaon Expressway, Faridabad, Haryana 121001, India
- Kalinga Institute of Industrial Technology, Bhubaneswar, Odisha 751024, India
| | - Sivaram V S Mylavarapu
- Laboratory of Cellular Dynamics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone Faridabad-Gurgaon Expressway, Faridabad, Haryana 121001, India
- Affiliated to the Manipal Academy of Higher Education, Manipal, Karnataka 576104, India
- Kalinga Institute of Industrial Technology, Bhubaneswar, Odisha 751024, India
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Kumar R, Saha S, Sinha B. Cell spread area and traction forces determine myosin-II-based cortex thickness regulation. Biochim Biophys Acta Mol Cell Res 2019; 1866:118516. [PMID: 31348954 DOI: 10.1016/j.bbamcr.2019.07.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 07/09/2019] [Accepted: 07/18/2019] [Indexed: 12/31/2022]
Abstract
Actomyosin network under the plasma membrane of cells forms a cortical layer that regulates cellular deformations during different processes. What regulates the cortex? Characterized by its thickness, it is believed to be regulated by actin dynamics, filament-length regulators and myosin motor proteins. However, its regulation by cellular morphology (e.g. cell spread area) or mechanical microenvironment (e.g. substrate stiffness) has remained largely unexplored. In this study, super- and high-resolution imaging of actin in CHO cells demonstrates that at high spread areas (>450 μm2), the cortex is thinner, better separated as layers, and sensitive to deactivation of myosin II motors or reduction of substrate stiffness (and traction forces). In less spread cells (<400 μm2) such perturbations do not elicit a response. Myosin IIA's mechanosensing is limited here due to its lowered actin-bound fraction and higher turnover rate. Cofilin, in line with its competitive inhibitory role, is found to be overexpressed in these cells. To establish the causal relation, we initiate a spread area drop by de-adhesion and find enhanced actin dynamics and fragmentation along with oscillations and increase in thickness. This is more correlated to the reduction of traction forces than the endocytosis-based reduction in cell volume. Cortex thickness control by spread area is also found be true during differentiation of THP-1 monocytes to macrophages. Thus, we propose that spread area regulates cortex and its thickness by traction-based mechanosensing of myosin II.
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Affiliation(s)
- Rinku Kumar
- Dept. of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, West Bengal, India
| | - Sajjita Saha
- Dept. of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, West Bengal, India
| | - Bidisha Sinha
- Dept. of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, West Bengal, India.
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Abstract
A thin layer of actin filaments in many eukaryotic cell types drives pivotal aspects of cell morphogenesis and is generally cited as the actin cortex. Myosin driven contractility and actin cytoskeleton membrane interactions form the basis of fundamental cellular processes such as cytokinesis, cell migration, and cortical flows. How the interplay between the actin cytoskeleton, the membrane, and actin binding proteins drives these processes is far from being understood. The complexity of the actin cortex in living cells and the hardly feasible manipulation of the omnipotent cellular key players, namely actin, myosin, and the membrane, are challenging in order to gain detailed insights about the underlying mechanisms. Recent progress in developing bottom-up in vitro systems where the actin cytoskeleton is combined with reconstituted membranes may provide a complementary route to reveal general principles underlying actin cortex properties. In this chapter the reconstitution of a minimal actin cortex by coupling actin filaments to a supported membrane is described. This minimal system may be very well suited to study for example protein interactions on membrane bound actin filaments in a very controlled and quantitative manner as it may be difficult to perform in living systems.
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Affiliation(s)
- Sven K Vogel
- Department of Cellular and Molecular Biophysics, Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, D-82152, Germany.
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8
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Cáceres R, Abou-Ghali M, Plastino J. Reconstituting the actin cytoskeleton at or near surfaces in vitro. Biochim Biophys Acta 2015; 1853:3006-14. [PMID: 26235437 DOI: 10.1016/j.bbamcr.2015.07.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 07/15/2015] [Accepted: 07/16/2015] [Indexed: 01/08/2023]
Abstract
Actin filament dynamics have been studied for decades in pure protein solutions or in cell extracts, but a breakthrough in the field occurred at the turn of the century when it became possible to reconstitute networks of actin filaments, growing in a controlled but physiological manner on surfaces, mimicking the actin assembly that occurs at the plasma membrane during cell protrusion and cell shape changes. The story begins with the bacteria Listeria monocytogenes, the study of which led to the reconstitution of cellular actin polymerization on a variety of supports including plastic beads. These studies made possible the development of liposome-type substrates for filament assembly and micropatterning of actin polymerization nucleation. Based on the accumulated expertise of the last 15 years, many exciting approaches are being developed, including the addition of myosin to biomimetic actin networks to study the interplay between actin structure and contractility. The field is now poised to make artificial cells with a physiological and dynamic actin cytoskeleton, and subsequently to put these cells together to make in vitro tissues. This article is part of a Special Issue entitled: Mechanobiology.
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Barreto S, Perrault CM, Lacroix D. Structural finite element analysis to explain cell mechanics variability. J Mech Behav Biomed Mater 2013; 38:219-31. [PMID: 24389336 DOI: 10.1016/j.jmbbm.2013.11.022] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 11/22/2013] [Accepted: 11/26/2013] [Indexed: 11/16/2022]
Abstract
The ability to model the mechanical responses of different cell types presents many opportunities to tissue engineering research to further identify changes from physiological conditions to disease. Using a previously validated finite element cell model we aim to show how variation of the material properties of the intracellular components affects cell response after compression and shearing. A parametric study was performed to understand the key mechanical features from different cell types, focussing on specific cytoskeleton components and prestress. Results show that actin cortex does not have a mechanical role in resisting shearing loading conditions. The sensitivity analysis predicted that cell force to compression and shearing is highly affected by changes in cortex thickness, cortex Young's modulus and rigidity of the remaining cytoplasm. Variation of prestress affects mainly the response of cells under shear loads and the model defines a relationship between cell force and prestress depending on the specific loading conditions, which is in good agreement with in vitro experiments. The results are used to make predictions that can relate mechanical properties with cell phenotype to be used as guidelines for individual cytoskeletal structures for future modelling efforts of the structure-function relationships of living cells.
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Affiliation(s)
- Sara Barreto
- INSIGNEO Institute for In Silico Medicine, Department of Mechanical Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD, United Kingdom
| | - Cecile M Perrault
- INSIGNEO Institute for In Silico Medicine, Department of Mechanical Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD, United Kingdom
| | - Damien Lacroix
- INSIGNEO Institute for In Silico Medicine, Department of Mechanical Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD, United Kingdom.
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