1
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Mendová K, Otáhal M, Drab M, Daniel M. Size Matters: Rethinking Hertz Model Interpretation for Cell Mechanics Using AFM. Int J Mol Sci 2024; 25:7186. [PMID: 39000293 PMCID: PMC11241038 DOI: 10.3390/ijms25137186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2024] [Revised: 06/17/2024] [Accepted: 06/25/2024] [Indexed: 07/16/2024] Open
Abstract
Cell mechanics are a biophysical indicator of cell state, such as cancer metastasis, leukocyte activation, and cell cycle progression. Atomic force microscopy (AFM) is a widely used technique to measure cell mechanics, where the Young modulus of a cell is usually derived from the Hertz contact model. However, the Hertz model assumes that the cell is an elastic, isotropic, and homogeneous material and that the indentation is small compared to the cell size. These assumptions neglect the effects of the cytoskeleton, cell size and shape, and cell environment on cell deformation. In this study, we investigated the influence of cell size on the estimated Young's modulus using liposomes as cell models. Liposomes were prepared with different sizes and filled with phosphate buffered saline (PBS) or hyaluronic acid (HA) to mimic the cytoplasm. AFM was used to obtain the force indentation curves and fit them to the Hertz model. We found that the larger the liposome, the lower the estimated Young's modulus for both PBS-filled and HA-filled liposomes. This suggests that the Young modulus obtained from the Hertz model is not only a property of the cell material but also depends on the cell dimensions. Therefore, when comparing or interpreting cell mechanics using the Hertz model, it is essential to account for cell size.
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Affiliation(s)
- Katarína Mendová
- Department of Mechanics, Biomechanics and Mechatronics, Faculty of Mechanical Engineering, Czech Technical University in Prague, Technická 4, 16000 Prague, Czech Republic;
| | - Martin Otáhal
- Department of Natural Sciences, Faculty of Biomedical Engineering, Czech Technical University in Prague, Náměstí Sítná 3105, 27201 Kladno, Czech Republic;
| | - Mitja Drab
- Laboratory of Biophysics, Faculty of Electrical Engineering, University of Ljubljana, Trzaska 25, 1000 Ljubljana, Slovenia;
| | - Matej Daniel
- Department of Mechanics, Biomechanics and Mechatronics, Faculty of Mechanical Engineering, Czech Technical University in Prague, Technická 4, 16000 Prague, Czech Republic;
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2
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Nie J, Lou S, Pollet AMAO, van Vegchel M, Bouten CVC, den Toonder JMJ. A Cell Pre-Wrapping Seeding Technique for Hydrogel-Based Tubular Organ-On-A-Chip. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2400970. [PMID: 38872259 DOI: 10.1002/advs.202400970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 04/28/2024] [Indexed: 06/15/2024]
Abstract
Organ-on-a-chip (OOC) models based on microfluidic technology are increasingly used to obtain mechanistic insight into (patho)physiological processes in humans, and they hold great promise for application in drug development and regenerative medicine. Despite significant progress in OOC development, several limitations of conventional microfluidic devices pose challenges. First, most microfluidic systems have rectangular cross sections and flat walls, and therefore tubular/ curved structures, like blood vessels and nephrons, are not well represented. Second, polymers used as base materials for microfluidic devices are much stiffer than in vivo extracellular matrix (ECM). Finally, in current cell seeding methods, challenges exist regarding precise control over cell seeding location, unreachable spaces due to flow resistances, and restricted dimensions/geometries. To address these limitations, an alternative cell seeding technique and a corresponding workflow is introduced to create circular cross-sectioned tubular OOC models by pre-wrapping cells around sacrificial fiber templates. As a proof of concept, a perfusable renal proximal tubule-on-a-chip is demonstrated with a diameter as small as 50 µm, cellular tubular structures with branches and curvature, and a preliminary vascular-renal tubule interaction model. The cell pre-wrapping seeding technique promises to enable the construction of diverse physiological/pathological models, providing tubular OOC systems for mechanistic investigations and drug development.
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Affiliation(s)
- Jing Nie
- Microsystems Research Section, Department of Mechanical Engineering, Eindhoven University of Technology, Eindhoven, 5600 MB, The Netherlands
- Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, Eindhoven, 5600 MB, The Netherlands
- Soft Tissue Engineering & Mechanobiology Research Section, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, 5600 MB, The Netherlands
| | - Sha Lou
- Microsystems Research Section, Department of Mechanical Engineering, Eindhoven University of Technology, Eindhoven, 5600 MB, The Netherlands
- Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, Eindhoven, 5600 MB, The Netherlands
- Soft Tissue Engineering & Mechanobiology Research Section, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, 5600 MB, The Netherlands
| | - Andreas M A O Pollet
- Microsystems Research Section, Department of Mechanical Engineering, Eindhoven University of Technology, Eindhoven, 5600 MB, The Netherlands
- Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, Eindhoven, 5600 MB, The Netherlands
| | - Manon van Vegchel
- Microsystems Research Section, Department of Mechanical Engineering, Eindhoven University of Technology, Eindhoven, 5600 MB, The Netherlands
- Soft Tissue Engineering & Mechanobiology Research Section, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, 5600 MB, The Netherlands
| | - Carlijn V C Bouten
- Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, Eindhoven, 5600 MB, The Netherlands
- Soft Tissue Engineering & Mechanobiology Research Section, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, 5600 MB, The Netherlands
| | - Jaap M J den Toonder
- Microsystems Research Section, Department of Mechanical Engineering, Eindhoven University of Technology, Eindhoven, 5600 MB, The Netherlands
- Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, Eindhoven, 5600 MB, The Netherlands
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3
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Lordon B, Campion T, Gibot L, Gallot G. Impact of trypsin on cell cytoplasm during detachment of cells studied by terahertz sensing. Biophys J 2024:S0006-3495(24)00406-5. [PMID: 38877703 DOI: 10.1016/j.bpj.2024.06.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 05/21/2024] [Accepted: 06/10/2024] [Indexed: 06/16/2024] Open
Abstract
Trypsin is a very common enzyme used in cell culture to harvest cells by cleaving the proteins responsible for cell adhesion. However, trypsin also induces undesirable effects on cells, such as altering membrane proteins and the cytoskeleton, changing the composition of the cytoplasm and the cell volume, and even leading to cell death when used improperly. Using attenuated total reflection in the terahertz domain, confocal microscopy, and the propidium iodide test, we quantified in real time the change in cytoplasmic content induced by trypsin proteolysis on Madin-Darby canine kidney epithelial cells. We have observed a cytoplasmic modification from the very first seconds of trypsinization, following the change of cell volume due to mechanical re-equilibrium of the membrane. We found that the cytoplasmic alteration is associated with a transfer of small solutes: electrolytes and metabolites. We also found a very good nonlinear correlation between the side effects monitored by terahertz sensing and the cell height, regardless of the dependence of the cell height on trypsin concentration and exposure time.
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Affiliation(s)
- Blandine Lordon
- LOB, Ecole Polytechnique, CNRS, INSERM, Institut Polytechnique de Paris, Palaiseau, France
| | - Tiffany Campion
- Laboratoire Softmat, Université de Toulouse, CNRS UMR 5623, Université Toulouse III - Paul Sabatier, Toulouse, France
| | - Laure Gibot
- Laboratoire Softmat, Université de Toulouse, CNRS UMR 5623, Université Toulouse III - Paul Sabatier, Toulouse, France
| | - Guilhem Gallot
- LOB, Ecole Polytechnique, CNRS, INSERM, Institut Polytechnique de Paris, Palaiseau, France.
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4
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Tervonen A, Korpela S, Nymark S, Hyttinen J, Ihalainen TO. The Effect of Substrate Stiffness on Elastic Force Transmission in the Epithelial Monolayers over Short Timescales. Cell Mol Bioeng 2023; 16:475-495. [PMID: 38099211 PMCID: PMC10716100 DOI: 10.1007/s12195-023-00772-0] [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: 10/28/2022] [Accepted: 06/26/2023] [Indexed: 12/17/2023] Open
Abstract
Purpose The importance of mechanical forces and microenvironment in guiding cellular behavior has been widely accepted. Together with the extracellular matrix (ECM), epithelial cells form a highly connected mechanical system subjected to various mechanical cues from their environment, such as ECM stiffness, and tensile and compressive forces. ECM stiffness has been linked to many pathologies, including tumor formation. However, our understanding of the effect of ECM stiffness and its heterogeneities on rapid force transduction in multicellular systems has not been fully addressed. Methods We used experimental and computational methods. Epithelial cells were cultured on elastic hydrogels with fluorescent nanoparticles. Single cells were moved by a micromanipulator, and epithelium and substrate deformation were recorded. We developed a computational model to replicate our experiments and quantify the force distribution in the epithelium. Our model further enabled simulations with local stiffness gradients. Results We found that substrate stiffness affects the force transduction and the cellular deformation following an external force. Also, our results indicate that the heterogeneities, e.g., gradients, in the stiffness can substantially influence the strain redistribution in the cell monolayers. Furthermore, we found that the cells' apico-basal elasticity provides a level of mechanical isolation between the apical cell-cell junctions and the basal focal adhesions. Conclusions Our simulation results show that increased ECM stiffness, e.g., due to a tumor, can mechanically isolate cells and modulate rapid mechanical signaling between cells over distances. Furthermore, the developed model has the potential to facilitate future studies on the interactions between epithelial monolayers and elastic substrates. Supplementary Information The online version of this article (10.1007/s12195-023-00772-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Aapo Tervonen
- BioMediTech, Faculty of Medicine and Health Technology, Tampere University, Arvo Ylpön katu 34, 33520 Tampere, Finland
- Department of Biological and Environmental Science, Faculty of Mathematics and Science, University of Jyväskylä, Survontie 9 C, 40500 Jyväskylä, Finland
| | - Sanna Korpela
- BioMediTech, Faculty of Medicine and Health Technology, Tampere University, Arvo Ylpön katu 34, 33520 Tampere, Finland
| | - Soile Nymark
- BioMediTech, Faculty of Medicine and Health Technology, Tampere University, Arvo Ylpön katu 34, 33520 Tampere, Finland
| | - Jari Hyttinen
- BioMediTech, Faculty of Medicine and Health Technology, Tampere University, Arvo Ylpön katu 34, 33520 Tampere, Finland
| | - Teemu O. Ihalainen
- BioMediTech, Faculty of Medicine and Health Technology, Tampere University, Arvo Ylpön katu 34, 33520 Tampere, Finland
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Shigemura K, Kuribayashi-Shigetomi K, Tanaka R, Yamasaki H, Okajima T. Mechanical properties of epithelial cells in domes investigated using atomic force microscopy. Front Cell Dev Biol 2023; 11:1245296. [PMID: 38046668 PMCID: PMC10690596 DOI: 10.3389/fcell.2023.1245296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 10/24/2023] [Indexed: 12/05/2023] Open
Abstract
As epithelial cells in vitro reach a highly confluent state, the cells often form a microscale dome-like architecture that encloses a fluid-filled lumen. The domes are stabilized by mechanical stress and luminal pressure. However, the mechanical properties of cells that form epithelial domes remain poorly characterized at the single-cell level. In this study, we used atomic force microscopy (AFM) to measure the mechanical properties of cells forming epithelial domes. AFM showed that the apparent Young's modulus of cells in domes was significantly higher when compared with that in the surrounding monolayer. AFM also showed that the stiffness and tension of cells in domes were positively correlated with the apical cell area, depending on the degree of cell stretching. This correlation disappeared when actin filaments were depolymerized or when the ATPase activity of myosin II was inhibited, which often led to a large fluctuation in dome formation. The results indicated that heterogeneous actomyosin structures organized by stretching single cells played a crucial role in stabilizing dome formation. Our findings provide new insights into the mechanical properties of three-dimensional deformable tissue explored using AFM at the single-cell level.
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Affiliation(s)
- Kenta Shigemura
- Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Japan
| | | | - Ryosuke Tanaka
- Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Japan
| | - Haruka Yamasaki
- Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Japan
| | - Takaharu Okajima
- Faculty of Information Science and Technology, Hokkaido University, Sapporo, Japan
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Ndlovu E, Malpartida L, Sultana T, Dahms TES, Dague E. Host Cell Geometry and Cytoskeletal Organization Governs Candida-Host Cell Interactions at the Nanoscale. ACS APPLIED MATERIALS & INTERFACES 2023. [PMID: 37888912 DOI: 10.1021/acsami.3c09870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2023]
Abstract
Candida is one of the most common opportunistic fungal pathogens in humans. Its adhesion to the host cell is required in parasitic states and is important for pathogenesis. Many studies have shown that there is an increased risk of developing candidiasis when normal tissue barriers are weakened or when immune defenses are compromised, for example, during cancer treatment that induces immunosuppression. The mechanical properties of malignant cells, such as adhesiveness and viscoelasticity, which contribute to cellular invasion and migration are different from those of noncancerous cells. To understand host invasion and its relationship with host cell health, we probed the interaction of Candida spp. with cancerous and noncancerous human cell lines using atomic force microscopy in the single-cell force spectroscopy mode. There was significant adhesion between Candida and human cells, with more adhesion to cancerous versus noncancerous cell lines. This increase in adhesion is related to the mechanobiological properties of cancer cells, which have a disorganized cytoskeleton and lower rigidity. Altered geometry and cytoskeletal disruption of the human cells impacted adhesion parameters, underscoring the role of cytoskeletal organization in Candida-human cell adhesion and implicating the manipulation of cell properties as a potential future therapeutic strategy.
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Affiliation(s)
- Easter Ndlovu
- Department of Chemistry and Biochemistry, University of Regina, 3737 Wascana Parkway, Regina S4S 0A2, Saskatchewan, Canada
| | - Lucas Malpartida
- National Centre for Scientific Research, Laboratory for Analysis and Architecture of Systems (LAAS), 7 Avenue du Colonel Roche, BP 54200, Toulouse cedex 4 31031, France
| | - Taranum Sultana
- Department of Chemistry and Biochemistry, University of Regina, 3737 Wascana Parkway, Regina S4S 0A2, Saskatchewan, Canada
| | - Tanya E S Dahms
- Department of Chemistry and Biochemistry, University of Regina, 3737 Wascana Parkway, Regina S4S 0A2, Saskatchewan, Canada
| | - Etienne Dague
- National Centre for Scientific Research, Laboratory for Analysis and Architecture of Systems (LAAS), 7 Avenue du Colonel Roche, BP 54200, Toulouse cedex 4 31031, France
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7
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Piskova T, Kozyrina AN, Di Russo J. Mechanobiological implications of age-related remodelling in the outer retina. BIOMATERIALS ADVANCES 2023; 147:213343. [PMID: 36801797 DOI: 10.1016/j.bioadv.2023.213343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 02/01/2023] [Accepted: 02/10/2023] [Indexed: 02/17/2023]
Abstract
The outer retina consists of the light-sensitive photoreceptors, the pigmented epithelium, and the choroid, which interact in a complex manner to sustain homeostasis. The organisation and function of these cellular layers are mediated by the extracellular matrix compartment named Bruch's membrane, situated between the retinal epithelium and the choroid. Like many tissues, the retina experiences age-related structural and metabolic changes, which are relevant for understanding major blinding diseases of the elderly, such as age-related macular degeneration. Compared with other tissues, the retina mainly comprises postmitotic cells, making it less able to maintain its mechanical homeostasis over the years functionally. Aspects of retinal ageing, like the structural and morphometric changes of the pigment epithelium and the heterogenous remodelling of the Bruch's membrane, imply changes in tissue mechanics and may affect functional integrity. In recent years, findings in the field of mechanobiology and bioengineering highlighted the importance of mechanical changes in tissues for understanding physiological and pathological processes. Here, we review the current knowledge of age-related changes in the outer retina from a mechanobiological perspective, aiming to generate food for thought for future mechanobiology studies in the outer retina.
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Affiliation(s)
- Teodora Piskova
- Interdisciplinary Centre for Clinical Research, RWTH Aachen University, Pauwelstrasse 30, 52074 Aachen, Germany; Institute of Molecular and Cellular Anatomy, RWTH Aachen University, Wendlingweg 2, 52074 Aachen, Germany
| | - Aleksandra N Kozyrina
- Interdisciplinary Centre for Clinical Research, RWTH Aachen University, Pauwelstrasse 30, 52074 Aachen, Germany; Institute of Molecular and Cellular Anatomy, RWTH Aachen University, Wendlingweg 2, 52074 Aachen, Germany
| | - Jacopo Di Russo
- Interdisciplinary Centre for Clinical Research, RWTH Aachen University, Pauwelstrasse 30, 52074 Aachen, Germany; Institute of Molecular and Cellular Anatomy, RWTH Aachen University, Wendlingweg 2, 52074 Aachen, Germany; DWI - Leibniz-Institute for Interactive Materials, Forckenbeckstrasse 50, 52074 Aachen, Germany.
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8
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Bermudez A, Gonzalez Z, Zhao B, Salter E, Liu X, Ma L, Jawed MK, Hsieh CJ, Lin NYC. Supracellular measurement of spatially varying mechanical heterogeneities in live monolayers. Biophys J 2022; 121:3358-3369. [PMID: 36028999 PMCID: PMC9515370 DOI: 10.1016/j.bpj.2022.08.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Revised: 07/10/2022] [Accepted: 08/19/2022] [Indexed: 11/29/2022] Open
Abstract
The mechanical properties of tissues have profound impacts on a wide range of biological processes such as embryo development (1,2), wound healing (3-6), and disease progression (7). Specifically, the spatially varying moduli of cells largely influence the local tissue deformation and intercellular interaction. Despite the importance of characterizing such a heterogeneous mechanical property, it has remained difficult to measure the supracellular modulus field in live cell layers with a high-throughput and minimal perturbation. In this work, we developed a monolayer effective modulus measurement by integrating a custom cell stretcher, light microscopy, and AI-based inference. Our approach first quantifies the heterogeneous deformation of a slightly stretched cell layer and converts the measured strain fields into an effective modulus field using an AI inference. This method allowed us to directly visualize the effective modulus distribution of thousands of cells virtually instantly. We characterized the mean value, SD, and correlation length of the effective cell modulus for epithelial cells and fibroblasts, which are in agreement with previous results. We also observed a mild correlation between cell area and stiffness in jammed epithelia, suggesting the influence of cell modulus on packing. Overall, our reported experimental platform provides a valuable alternative cell mechanics measurement tool that can be integrated with microscopy-based characterizations.
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Affiliation(s)
- Alexandra Bermudez
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, California 90095, USA; Department of Bioengineering, University of California, Los Angeles, California.
| | - Zachary Gonzalez
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, California 90095, USA; Department of Physics and Astronomy, University of California, Los Angeles, California
| | - Bao Zhao
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, California 90095, USA
| | - Ethan Salter
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, California 90095, USA; Department of Bioengineering, University of California, Los Angeles, California
| | - Xuanqing Liu
- Department of Computer Science, University of California, Los Angeles, California
| | - Leixin Ma
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, California 90095, USA
| | - Mohammad Khalid Jawed
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, California 90095, USA
| | - Cho-Jui Hsieh
- Department of Computer Science, University of California, Los Angeles, California
| | - Neil Y C Lin
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, California 90095, USA; Department of Bioengineering, University of California, Los Angeles, California; Institute for Quantitative and Computational Biosciences, University of California, Los Angeles, Los Angeles, California.
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9
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Lee SW, Morishita Y. Two types of critical cell density for mechanical elimination of abnormal cell clusters from epithelial tissue. PLoS Comput Biol 2022; 18:e1010178. [PMID: 35696420 PMCID: PMC9232172 DOI: 10.1371/journal.pcbi.1010178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 06/24/2022] [Accepted: 05/07/2022] [Indexed: 11/18/2022] Open
Abstract
Recent technological advances in high-resolution imaging and artificial modulation of genetic functions at different times and regions have enabled direct observations of the formation and elimination of abnormal cell populations. A recent trend in cell competition research is the incorporation of cell mechanics. In different tissues and species, abnormal cells developing in epithelial tissues are mechanically eliminated by cell contraction via actomyosin accumulation at the interface between normal and abnormal cells. This mechanical cell elimination process has attracted attention as a potential universal defense mechanism. Here, we theoretically examined the conditions for mechanical elimination of growing abnormal cell populations. Simulations and mathematical analyses using a vertex dynamics model revealed two types of critical cell density associated with mechanical elimination of abnormal cell clusters. One is a subtype of homeostatic density, in which the frequencies of spontaneous mechanical cell elimination and proliferation are balanced, even if no explicit dependence of proliferation or apoptosis on the cell density is assumed. This density is related to the mechanical stability of a single cell. The other is density related to mechanical stability as a cell population under external pressure. Both density types are determined by tissue mechanical properties. In solid tissues, the former type is reached first as the intensity of interfacial contraction increases, and it functions as a critical density. On the other hand, the latter type becomes critical when tissues are highly fluid. The derived analytical solution explicitly reveals the dependence of critical contractile force and density on different parameters. We also found a negative correlation between the proliferation rate of abnormal cells and the likelihood of the abnormal cell population expanding by escaping elimination. This is counterintuitive because in the context of cell competition, fast-growing cell populations generally win. These findings provide new insight into, and interpretation of, the results from experimental studies. High-resolution imaging techniques have revealed that abnormal cells developing in epithelial tissues are mechanically eliminated via contraction at the interface between the abnormal cells and normal surrounding cells. This phenomenon is seen in various species and tissues and thus is regarded as a primitive defense system against precancerous cells common to all animals. For comprehensive understanding of this potential defense system, we derived mathematical conditions to achieve mechanical elimination of growing abnormal cell populations. We identified two characteristic cell density types associated with successful mechanical elimination of abnormal cell clusters. Both are determined by tissue physical properties, and the smaller of the two functions as a critical density above which abnormal cell populations cannot exist. We also found a counterintuitive phenomenon in which slower proliferation of abnormal cells promotes their growth as a population. Our results will help elucidate the mechanisms of intrinsic tissue defenses against cancer from the perspective of cell mechanics.
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Affiliation(s)
- Sang-Woo Lee
- Laboratory for Developmental Morphogeometry, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
| | - Yoshihiro Morishita
- Laboratory for Developmental Morphogeometry, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
- * E-mail:
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10
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Harmand N, Dervaux J, Poulard C, Hénon S. Thickness of epithelia on wavy substrates: measurements and continuous models. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2022; 45:53. [PMID: 35661937 DOI: 10.1140/epje/s10189-022-00206-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 05/09/2022] [Indexed: 06/15/2023]
Abstract
We measured the thickness of MDCK epithelia grown on substrates with a sinusoidal profile. We show that while at long wavelength the profile of the epithelium follows that of the substrate, at short wavelengths cells are thicker in valleys than on ridges. This is reminiscent of the so-called «healing length in the case of a thin liquid film wetting a rough solid substrate. We explore the ability of continuum mechanics models to account for these observations. Modeling the epithelium as a thin liquid film, with surface tension, does not fully account for the measurements. Neither does modeling the epithelium as a thin incompressible elastic film. On the contrary, the addition of an apical active stress gives satisfactory agreement with measurements, with one fitting parameter, the ratio between the active stress and the elastic modulus.
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Affiliation(s)
- Nicolas Harmand
- Université Paris Cité, CNRS, Matiére et Systémes Complexes, UMR 7057,, Paris, France
| | - Julien Dervaux
- Université Paris Cité, CNRS, Matiére et Systémes Complexes, UMR 7057,, Paris, France
| | - Christophe Poulard
- Laboratoire de Physique des Solides, CNRS, UMR 8502, Université Paris-Saclay, Orsay, France
| | - Sylvie Hénon
- Université Paris Cité, CNRS, Matiére et Systémes Complexes, UMR 7057,, Paris, France.
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11
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Mukherjee K, Gu C, Collins A, Mettlen M, Samelko B, Altintas MM, Sudhini YR, Wang X, Bouley R, Brown D, Pedro BP, Bane SL, Gupta V, Brinkkoetter PT, Hagmann H, Reiser J, Sever S. Simultaneous stabilization of actin cytoskeleton in multiple nephron-specific cells protects the kidney from diverse injury. Nat Commun 2022; 13:2422. [PMID: 35504916 PMCID: PMC9065033 DOI: 10.1038/s41467-022-30101-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 04/04/2022] [Indexed: 02/07/2023] Open
Abstract
Chronic kidney diseases and acute kidney injury are mechanistically distinct kidney diseases. While chronic kidney diseases are associated with podocyte injury, acute kidney injury affects renal tubular epithelial cells. Despite these differences, a cardinal feature of both acute and chronic kidney diseases is dysregulated actin cytoskeleton. We have shown that pharmacological activation of GTPase dynamin ameliorates podocyte injury in murine models of chronic kidney diseases by promoting actin polymerization. Here we establish dynamin's role in modulating stiffness and polarity of renal tubular epithelial cells by crosslinking actin filaments into branched networks. Activation of dynamin's crosslinking capability by a small molecule agonist stabilizes the actomyosin cortex of the apical membrane against injury, which in turn preserves renal function in various murine models of acute kidney injury. Notably, a dynamin agonist simultaneously attenuates podocyte and tubular injury in the genetic murine model of Alport syndrome. Our study provides evidence for the feasibility and highlights the benefits of novel holistic nephron-protective therapies.
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Affiliation(s)
- Kamalika Mukherjee
- Department of Medicine, Harvard Medical School and Division of Nephrology, Massachusetts General Hospital, Boston, MA, USA
| | - Changkyu Gu
- Department of Medicine, Harvard Medical School and Division of Nephrology, Massachusetts General Hospital, Boston, MA, USA
| | - Agnieszka Collins
- Department of Medicine, Harvard Medical School and Division of Nephrology, Massachusetts General Hospital, Boston, MA, USA
| | - Marcel Mettlen
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Beata Samelko
- Department of Medicine, Rush University Medical Center, Chicago, IL, USA
| | - Mehmet M Altintas
- Department of Medicine, Rush University Medical Center, Chicago, IL, USA
| | | | - Xuexiang Wang
- Department of Medicine, Rush University Medical Center, Chicago, IL, USA
| | - Richard Bouley
- Department of Medicine, Harvard Medical School and Division of Nephrology, Massachusetts General Hospital, Boston, MA, USA
| | - Dennis Brown
- Department of Medicine, Harvard Medical School and Division of Nephrology, Massachusetts General Hospital, Boston, MA, USA
| | - Bradley P Pedro
- Department of Medicine, Harvard Medical School and Division of Nephrology, Massachusetts General Hospital, Boston, MA, USA
| | - Susan L Bane
- Department of Chemistry, Binghamton University, State University of New York, Binghamton, NY, USA
| | - Vineet Gupta
- Department of Medicine, Rush University Medical Center, Chicago, IL, USA
| | - Paul T Brinkkoetter
- Department of Internal Medicine-Center for Molecular Medicine Cologne, University of Cologne and Faculty of Medicine-University Hospital Cologne, Cologne, Germany
- Cologne Cluster of Excellence on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Systems Biology of Ageing Cologne (Sybacol), Cologne, Germany
| | - Henning Hagmann
- Department of Internal Medicine-Center for Molecular Medicine Cologne, University of Cologne and Faculty of Medicine-University Hospital Cologne, Cologne, Germany
- Cologne Cluster of Excellence on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Systems Biology of Ageing Cologne (Sybacol), Cologne, Germany
| | - Jochen Reiser
- Department of Medicine, Rush University Medical Center, Chicago, IL, USA.
| | - Sanja Sever
- Department of Medicine, Harvard Medical School and Division of Nephrology, Massachusetts General Hospital, Boston, MA, USA.
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12
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Vicar T, Chmelik J, Navratil J, Kolar R, Chmelikova L, Cmiel V, Jagos J, Provaznik I, Masarik M, Gumulec J. Cancer Cells Viscoelasticity Measurement by Quantitative Phase and Flow Stress Induction. Biophys J 2022; 121:1632-1642. [PMID: 35390297 PMCID: PMC9117928 DOI: 10.1016/j.bpj.2022.04.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 03/02/2022] [Accepted: 03/31/2022] [Indexed: 11/02/2022] Open
Abstract
Cell viscoelastic properties are affected by the cell cycle, differentiation, pathological processes such as malignant transformation. Therefore, evaluation of the mechanical properties of the cells proved to be an approach to obtaining information on the functional state of the cells. Most of the currently used methods for cell mechanophenotypisation are limited by low robustness or the need for highly expert operation. In this paper, the system and method for viscoelasticity measurement using shear stress induction by fluid flow is described and tested. Quantitative Phase Imaging (QPI) is used for image acquisition because this technique enables to quantify optical path length delays introduced by the sample, thus providing a label-free objective measure of morphology and dynamics. Viscosity and elasticity determination were refined using a new approach based on the linear system model and parametric deconvolution. The proposed method allows high-throughput measurements during live cell experiments and even through a time-lapse, where we demonstrated the possibility of simultaneous extraction of shear modulus, viscosity, cell morphology, and QPI-derived cell parameters like circularity or cell mass. Additionally, the proposed method provides a simple approach to measure cell refractive index with the same setup, which is required for reliable cell height measurement with QPI, an essential parameter for viscoelasticity calculation. Reliability of the proposed viscoelasticity measurement system was tested in several experiments including cell types of different Young/shear modulus and treatment with cytochalasin D or docetaxel, and an agreement with atomic force microscopy was observed. The applicability of the proposed approach was also confirmed by a time-lapse experiment with cytochalasin D washout, where an increase of stiffness corresponded to actin repolymerisation in time.
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Affiliation(s)
- Tomas Vicar
- Department of Biomedical Engineering, Faculty of Electrical Engineering and Communications, Brno University of Technology, Brno, Czech Republic; Department of Pathological Physiology, Masaryk University, Brno, Czech Republic
| | - Jiri Chmelik
- Department of Biomedical Engineering, Faculty of Electrical Engineering and Communications, Brno University of Technology, Brno, Czech Republic
| | - Jiri Navratil
- Department of Pathological Physiology, Masaryk University, Brno, Czech Republic
| | - Radim Kolar
- Department of Biomedical Engineering, Faculty of Electrical Engineering and Communications, Brno University of Technology, Brno, Czech Republic
| | - Larisa Chmelikova
- Department of Biomedical Engineering, Faculty of Electrical Engineering and Communications, Brno University of Technology, Brno, Czech Republic
| | - Vratislav Cmiel
- Department of Biomedical Engineering, Faculty of Electrical Engineering and Communications, Brno University of Technology, Brno, Czech Republic
| | - Jiri Jagos
- Dept. of Tissue Biomechanics and Numerical Modelling in Medicine, Faculty of Mechanical Engineering, Brno University of Technology, Brno, Czech Republic
| | - Ivo Provaznik
- Department of Biomedical Engineering, Faculty of Electrical Engineering and Communications, Brno University of Technology, Brno, Czech Republic
| | - Michal Masarik
- Department of Pathological Physiology, Masaryk University, Brno, Czech Republic
| | - Jaromir Gumulec
- Department of Pathological Physiology, Masaryk University, Brno, Czech Republic.
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13
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Viscoelastic properties of epithelial cells. Biochem Soc Trans 2021; 49:2687-2695. [PMID: 34854895 DOI: 10.1042/bst20210476] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 09/16/2021] [Accepted: 10/08/2021] [Indexed: 11/17/2022]
Abstract
Epithelial cells form tight barriers that line both the outer and inner surfaces of organs and cavities and therefore face diverse environmental challenges. The response to these challenges relies on the cells' dynamic viscoelastic properties, playing a pivotal role in many biological processes such as adhesion, growth, differentiation, and motility. Therefore, the cells usually adapt their viscoelastic properties to mirror the environment that determines their fate and vitality. Albeit not a high-throughput method, atomic force microscopy is still among the dominating methods to study the mechanical properties of adherent cells since it offers a broad range of forces from Piconewtons to Micronewtons at biologically significant time scales. Here, some recent work of deformation studies on epithelial cells is reviewed with a focus on viscoelastic models suitable to describe force cycle measurements congruent with the architecture of the actin cytoskeleton. The prominent role of the cortex in the cell's response to external forces is discussed also in the context of isolated cortex extracts on porous surfaces.
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14
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Skamrahl M, Pang H, Ferle M, Gottwald J, Rübeling A, Maraspini R, Honigmann A, Oswald TA, Janshoff A. Tight Junction ZO Proteins Maintain Tissue Fluidity, Ensuring Efficient Collective Cell Migration. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2100478. [PMID: 34382375 PMCID: PMC8498871 DOI: 10.1002/advs.202100478] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 06/18/2021] [Indexed: 06/01/2023]
Abstract
Tight junctions (TJs) are essential components of epithelial tissues connecting neighboring cells to provide protective barriers. While their general function to seal compartments is well understood, their role in collective cell migration is largely unexplored. Here, the importance of the TJ zonula occludens (ZO) proteins ZO1 and ZO2 for epithelial migration is investigated employing video microscopy in conjunction with velocimetry, segmentation, cell tracking, and atomic force microscopy/spectroscopy. The results indicate that ZO proteins are necessary for fast and coherent migration. In particular, ZO1 and 2 loss (dKD) induces actomyosin remodeling away from the central cortex towards the periphery of individual cells, resulting in altered viscoelastic properties. A tug-of-war emerges between two subpopulations of cells with distinct morphological and mechanical properties: 1) smaller and highly contractile cells with an outward bulging apical membrane, and 2) larger, flattened cells, which, due to tensile stress, display a higher proliferation rate. In response, the cell density increases, leading to crowding-induced jamming and more small cells over time. Co-cultures comprising wildtype and dKD cells migrate inefficiently due to phase separation based on differences in contractility rather than differential adhesion. This study shows that ZO proteins are necessary for efficient collective cell migration by maintaining tissue fluidity and controlling proliferation.
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Affiliation(s)
- Mark Skamrahl
- Institute of Physical ChemistryUniversity of GöttingenTammannstr. 6Göttingen37077Germany
| | - Hongtao Pang
- Institute of Physical ChemistryUniversity of GöttingenTammannstr. 6Göttingen37077Germany
| | - Maximilian Ferle
- Institute of Physical ChemistryUniversity of GöttingenTammannstr. 6Göttingen37077Germany
| | - Jannis Gottwald
- Institute of Physical ChemistryUniversity of GöttingenTammannstr. 6Göttingen37077Germany
| | - Angela Rübeling
- Institute of Organic and Biomolecular ChemistryUniversity of GöttingenTammannstr. 2Göttingen37077Germany
| | - Riccardo Maraspini
- Max Planck Institute of Molecular Cell Biology and GeneticsPfotenhauerstraße 108Dresden01307Germany
| | - Alf Honigmann
- Max Planck Institute of Molecular Cell Biology and GeneticsPfotenhauerstraße 108Dresden01307Germany
| | - Tabea A. Oswald
- Institute of Organic and Biomolecular ChemistryUniversity of GöttingenTammannstr. 2Göttingen37077Germany
| | - Andreas Janshoff
- Institute of Physical ChemistryUniversity of GöttingenTammannstr. 6Göttingen37077Germany
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15
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Aureille J, Pezet M, Pernet L, Mazzega J, Grichine A, Guilluy C, Dolega ME. Cell fluorescence photoactivation as a method to select and study cellular subpopulations grown in mechanically heterogeneous environments. Mol Biol Cell 2021; 32:1409-1416. [PMID: 34133212 PMCID: PMC8351743 DOI: 10.1091/mbc.e20-10-0676] [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] [Indexed: 11/18/2022] Open
Abstract
A central challenge to the biology of development and disease is deciphering how individual cells process and respond to numerous biochemical and mechanical signals originating from the environment. Recent advances in genomic studies enabled the acquisition of information about population heterogeneity; however, these so far are poorly linked with the spatial heterogeneity of biochemical and mechanical cues. Whereas in vitro models offer superior control over spatiotemporal distribution of numerous mechanical parameters, researchers are limited by the lack of methods to select subpopulations of cells in order to understand how environmental heterogeneity directs the functional collective response. To circumvent these limitations, we present a method based on the use of photo convertible proteins, which when expressed within cells and activated with light, gives a stable fluorescence fingerprint enabling subsequent sorting and lysis for genomics analysis. Using this technique, we study the spatial distribution of genetic alterations on well-characterized local mechanical stimulation within the epithelial monolayer. Our method is an in vitro alternative to laser microdissection, which so far has found a broad application in ex vivo studies.
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Affiliation(s)
- Julien Aureille
- Institute for Advanced Biosciences, University Grenoble Alpes, Inserm U1209, CNRS UMR 5309 Grenoble, France
| | - Mylène Pezet
- Institute for Advanced Biosciences, University Grenoble Alpes, Inserm U1209, CNRS UMR 5309 Grenoble, France
| | - Lydia Pernet
- Institute for Advanced Biosciences, University Grenoble Alpes, Inserm U1209, CNRS UMR 5309 Grenoble, France
| | - Jacques Mazzega
- Institute for Advanced Biosciences, University Grenoble Alpes, Inserm U1209, CNRS UMR 5309 Grenoble, France
| | - Alexei Grichine
- Institute for Advanced Biosciences, University Grenoble Alpes, Inserm U1209, CNRS UMR 5309 Grenoble, France
| | - Christophe Guilluy
- Institute for Advanced Biosciences, University Grenoble Alpes, Inserm U1209, CNRS UMR 5309 Grenoble, France
| | - Monika Elzbieta Dolega
- Institute for Advanced Biosciences, University Grenoble Alpes, Inserm U1209, CNRS UMR 5309 Grenoble, France
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16
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Lee H, Bonin K, Guthold M. Human mammary epithelial cells in a mature, stratified epithelial layer flatten and stiffen compared to single and confluent cells. Biochim Biophys Acta Gen Subj 2021; 1865:129891. [PMID: 33689830 DOI: 10.1016/j.bbagen.2021.129891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 02/07/2021] [Accepted: 03/03/2021] [Indexed: 10/22/2022]
Abstract
BACKGROUND The epithelium forms a protective barrier against external biological, chemical and physical insults. So far, AFM-based, micro-mechanical measurements have only been performed on single cells and confluent cells, but not yet on cells in mature layers. METHODS Using a combination of atomic force, fluorescence and confocal microscopy, we determined the changes in stiffness, morphology and actin distribution of human mammary epithelial cells (HMECs) as they transition from single cells to confluency to a mature layer. RESULTS Single HMECs have a tall, round (planoconvex) morphology, have actin stress fibers at the base, have diffuse cortical actin, and have a stiffness of 1 kPa. Confluent HMECs start to become flatter, basal actin stress fibers start to disappear, and actin accumulates laterally where cells abut. Overall stiffness is still 1 kPa with two-fold higher stiffness in the abutting regions. As HMECs mature and form multilayered structures, cells on apical surfaces become flatter (apically more level), wider, and seven times stiffer (mean, 7 kPa) than single and confluent cells. The main drivers of these changes are actin filaments, as cells show strong actin accumulation in the regions where cells adjoin, and in the apical regions. CONCLUSIONS HMECs stiffen, flatten and redistribute actin upon transiting from single cells to mature, confluent layers. GENERAL SIGNIFICANCE Our findings advance the understanding of breast ductal morphogenesis and mechanical homeostasis.
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Affiliation(s)
- Hyunsu Lee
- Department of Physics, Wake Forest University, Winston-Salem, NC 27109, USA
| | - Keith Bonin
- Department of Physics, Wake Forest University, Winston-Salem, NC 27109, USA
| | - Martin Guthold
- Department of Physics, Wake Forest University, Winston-Salem, NC 27109, USA.
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17
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Duncan-Lowey JK, Wiscovitch AL, Wood TE, Goldberg MB, Russo BC. Shigella flexneri Disruption of Cellular Tension Promotes Intercellular Spread. Cell Rep 2020; 33:108409. [PMID: 33238111 PMCID: PMC7792532 DOI: 10.1016/j.celrep.2020.108409] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 09/25/2020] [Accepted: 10/29/2020] [Indexed: 01/18/2023] Open
Abstract
During infection, some bacterial pathogens invade the eukaryotic cytosol and spread between cells of an epithelial monolayer. Intercellular spread occurs when these pathogens push against the plasma membrane, forming protrusions that are engulfed by adjacent cells. Here, we show that IpaC, a Shigella flexneri type 3 secretion system protein, binds the host cell-adhesion protein β-catenin and facilitates efficient protrusion formation. S. flexneri producing a point mutant of IpaC that cannot interact with β-catenin is defective in protrusion formation and spread. Spread is restored by chemical reduction of intercellular tension or genetic depletion of β-catenin, and the magnitude of the protrusion defect correlates with membrane tension, indicating that IpaC reduces membrane tension, which facilitates protrusion formation. IpaC stabilizes adherens junctions and does not alter β-catenin localization at the membrane. Thus, Shigella, like other bacterial pathogens, reduces intercellular tension to efficiently spread between cells.
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Affiliation(s)
- Jeffrey K. Duncan-Lowey
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Present address: Department of Immunobiology, Yale School of Medicine, New Haven, CT 06511, USA
| | - Alexandra L. Wiscovitch
- Research Scholar Initiative, The Graduate School of Arts and Sciences, Harvard University, Cambridge, MA 02138, USA,Present address: Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL 32611, USA
| | - Thomas E. Wood
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Marcia B. Goldberg
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA,Correspondence: (M.B.G.), (B.C.R.)
| | - Brian C. Russo
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA,Present address: Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO 80045, USA,Lead Contact,Correspondence: (M.B.G.), (B.C.R.)
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18
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Kim H, Witt H, Oswald TA, Tarantola M. Adhesion of Epithelial Cells to PNIPAm Treated Surfaces for Temperature-Controlled Cell-Sheet Harvesting. ACS APPLIED MATERIALS & INTERFACES 2020; 12:33516-33529. [PMID: 32631046 PMCID: PMC7467562 DOI: 10.1021/acsami.0c09166] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Stimuli responsive polymer coatings are a common motive for designing surfaces for cell biological applications. In the present study, we have characterized temperature dependent adhesive properties of poly(N-isopropylacrylamide) (PNIPAm) microgel coated surfaces (PMS) using various atomic force microscopy based approaches. We imaged and quantified the material properties of PMS upon a temperature switch using quantitative AFM imaging but also employed single-cell force spectroscopy (SCFS) before and after decreasing the temperature to assess the forces and work of initial adhesion between cells and PMS. We performed a detailed analysis of steps in the force-distance curves. Finally, we applied colloid probe atomic force microscopy (CP-AFM) to analyze the adhesive properties of two major components of the extracellular matrix to PMS under temperature control, namely collagen I and fibronectin. In combination with confocal imaging, we could show that these two ECM components differ in their detachment properties from PNIPAm microgel films upon cell harvesting, and thus gained a deeper understanding of cell-sheet maturation and harvesting process and the involved partial ECM dissolution.
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Affiliation(s)
- Hyejeong Kim
- Max Planck Institute
for Dynamics and Self Organization (MPIDS), Am Fassberg 17, 37077 Göttingen, Germany
| | - Hannes Witt
- Max Planck Institute
for Dynamics and Self Organization (MPIDS), Am Fassberg 17, 37077 Göttingen, Germany
| | - Tabea A. Oswald
- Institute of Organic and Biomolecular Chemistry, University of Göttingen, Tammannstrasse 2, 37077 Göttingen, Germany
| | - Marco Tarantola
- Max Planck Institute
for Dynamics and Self Organization (MPIDS), Am Fassberg 17, 37077 Göttingen, Germany
- Institute for Dynamics of Complex Systems, University of Göttingen, Friedrich-Hund Platz 1, 37073 Göttingen, Germany
- E-mail: . Phone: +49-551-5176-316
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19
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Ferreira JPS, Kuang M, Parente MPL, Natal Jorge RM, Wang R, Eppell SJ, Damaser M. Altered mechanics of vaginal smooth muscle cells due to the lysyl oxidase-like1 knockout. Acta Biomater 2020; 110:175-187. [PMID: 32335309 DOI: 10.1016/j.actbio.2020.03.046] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 03/26/2020] [Accepted: 03/31/2020] [Indexed: 01/04/2023]
Abstract
The remodeling mechanisms that cause connective tissue of the vaginal wall, consisting mostly of smooth muscle, to weaken after vaginal delivery are not fully understood. Abnormal remodeling after delivery can contribute to development of pelvic organ prolapse and other pelvic floor disorders. The present study used vaginal smooth muscle cells (vSMCs) isolated from knockout mice lacking the expression of the lysyl oxidase-like1 (LOXL1) enzyme, a well-characterized animal model for pelvic organ prolapse. We tested if vaginal smooth muscle cells from LOXL1 knockout mice have altered mechanics including stiffness and surface adhesion. Using atomic force microscopy, we performed nanoindentations on both isolated and confluent cells to evaluate the effect of LOXL1 knockout on in vitro cultures of vSMCs cells from nulliparous mice. The results show that LOXL1 knockout vSMCs have increased stiffness in pre-confluent but decreased stiffness in confluent cultures (p* < 0.05) and significant decreased surface adhesion in pre-confluent cultures (p* < 0.05). This study provides evidence that the weakening of vaginal connective tissue in the absense of LOXL1 changes the mechanical properties of the vSMCs. STATEMENT OF SIGNIFICANCE: Pelvic organ prolapse is a common condition affecting millions of women worldwide, which significantly impacts their quality of life. Alterations in vaginal and pelvic floor mechanical properties can change their ability to support the pelvic organs. This study provides evidence of altered stiffness of vaginal smooth muscle cells from mice resembling pelvic organ prolapse. The results from this study set a foundation to develop pathophysiology-driven therapies focused on the interplay between smooth muscle mechanics and extracellular matrix remodeling.
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Affiliation(s)
- J P S Ferreira
- Department of Mechanical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal; Institute of Science and Innovation in Mechanical and Industrial Engineering, Porto, Portugal; Department of Biomedical Engineering, Lerner Research Institute and Glickman Urological Institute, Cleveland Clinic Foundation, OH, USA.
| | - M Kuang
- Department of Biomedical Engineering, Lerner Research Institute and Glickman Urological Institute, Cleveland Clinic Foundation, OH, USA
| | - M P L Parente
- Department of Mechanical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal; Institute of Science and Innovation in Mechanical and Industrial Engineering, Porto, Portugal
| | - R M Natal Jorge
- Department of Mechanical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal; Institute of Science and Innovation in Mechanical and Industrial Engineering, Porto, Portugal
| | - R Wang
- Department of Chemistry, Illinois Institute of Technology, Chicago, IL, USA
| | - S J Eppell
- Department of Biomedical Engineering, Case Western Reserve, Cleveland, OH, USA
| | - M Damaser
- Department of Biomedical Engineering, Lerner Research Institute and Glickman Urological Institute, Cleveland Clinic Foundation, OH, USA; Department of Biomedical Engineering, Case Western Reserve, Cleveland, OH, USA; Advanced Platform Technology Center, Louis Stokes Cleveland Veteran's Administration Medical Center, Cleveland, OH, USA.
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20
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Lv JQ, Chen PC, Góźdź WT, Li B. Mechanical adaptions of collective cells nearby free tissue boundaries. J Biomech 2020; 104:109763. [PMID: 32224050 DOI: 10.1016/j.jbiomech.2020.109763] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 03/16/2020] [Accepted: 03/18/2020] [Indexed: 11/19/2022]
Abstract
Mechanical adaptions of cells, including stiffness variation, cytoskeleton remodeling, motion coordination, and shape changing, are essential for tissue morphogenesis, wound healing, and malignant progression. In this paper, we take confluent monolayers of Madin-Darby canine kidney (MDCK) and mouse myoblast (C2C12) cells as model systems to probe how cells collectively adapt their mechanical features in response to a free tissue boundary. We show that the free boundary not only can trigger unjamming transition but also induces cell fluidization nearby the boundary. The Young's moduli of cells near the boundary are found to be much lower than those of interior cells. We demonstrate that the stiffness of cells in monolayers with a free tissue boundary exhibits negative dependence on the projected cell area, in contrast to previous studies where cells were found to stiffen as cellular area increases in a confluent MDCK monolayer without boundary. In addition, the free tissue boundary may activate cell remodeling, rendering volume enlargement and cell-specified cytoskeleton organization. Our study emphasizes the important role of geometrical boundary in regulating biomechanical properties of cell aggregates.
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Affiliation(s)
- Jian-Qing Lv
- Institute of Biomechanics and Medical Engineering, Applied Mechanics Laboratory, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
| | - Peng-Cheng Chen
- Institute of Biomechanics and Medical Engineering, Applied Mechanics Laboratory, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
| | - Wojciech T Góźdź
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Bo Li
- Institute of Biomechanics and Medical Engineering, Applied Mechanics Laboratory, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China.
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21
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Fink A, Brückner DB, Schreiber C, Röttgermann PJF, Broedersz CP, Rädler JO. Area and Geometry Dependence of Cell Migration in Asymmetric Two-State Micropatterns. Biophys J 2020; 118:552-564. [PMID: 31864660 PMCID: PMC7002917 DOI: 10.1016/j.bpj.2019.11.3389] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 10/11/2019] [Accepted: 11/12/2019] [Indexed: 12/19/2022] Open
Abstract
Microstructured surfaces provide a unique framework to probe cell migration and cytoskeletal dynamics in a standardized manner. Here, we report on the steady-state occupancy probability of cells in asymmetric two-state microstructures that consist of two fibronectin-coated adhesion sites connected by a thin guidance cue. In these dumbbell-like structures, cells transition between the two sites in a repeated and stochastic manner, and average dwell times in the respective microenvironments are determined from the cell trajectories. We study the dynamics of human breast carcinoma cells (MDA-MB-231) in these microstructures as a function of area, shape, and orientation of the adhesion sites. On square adhesive sites with different areas, we find that the occupancy probability ratio is directly proportional to the ratio of corresponding adhesion site areas. These asymmetries are well captured by a simple model for the stochastic nonlinear dynamics of the cells, which reveals generic features of the motion. Sites of equal area but different shape lead to equal occupancy if shapes are isotropic (e.g., squared or circular). In contrast, an asymmetry in the occupancy is induced by anisotropic shapes like rhombi, triangles, or rectangles that enable motion in the direction perpendicular to the transition axis. Analysis of the two-dimensional motion of cells between two rectangles with orthogonal orientation suggests that cellular transition rates depend on the cell polarization induced by anisotropic micropatterns. Taken together, our results illustrate how two-state micropatterns provide a dynamic migration assay with distinct dwell times and relative cell occupancy as readouts, which may be useful to probe cell-microenvironment interactions.
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Affiliation(s)
- Alexandra Fink
- Faculty of Physics and Center for NanoScience, Ludwig-Maximilians-Universität, München, Germany
| | - David B Brückner
- Faculty of Physics and Center for NanoScience, Ludwig-Maximilians-Universität, München, Germany; Arnold-Sommerfeld-Center for Theoretical Physics and Center for NanoScience, Ludwig-Maximilians-Universität, München, Germany
| | - Christoph Schreiber
- Faculty of Physics and Center for NanoScience, Ludwig-Maximilians-Universität, München, Germany
| | - Peter J F Röttgermann
- Faculty of Physics and Center for NanoScience, Ludwig-Maximilians-Universität, München, Germany
| | - Chase P Broedersz
- Faculty of Physics and Center for NanoScience, Ludwig-Maximilians-Universität, München, Germany; Arnold-Sommerfeld-Center for Theoretical Physics and Center for NanoScience, Ludwig-Maximilians-Universität, München, Germany
| | - Joachim O Rädler
- Faculty of Physics and Center for NanoScience, Ludwig-Maximilians-Universität, München, Germany.
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