1
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Rajput SS, Singh SB, Subramanyam D, Patil S. Soft glassy rheology of single cells with pathogenic protein aggregates. SOFT MATTER 2024; 20:6266-6274. [PMID: 39054893 DOI: 10.1039/d4sm00595c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/27/2024]
Abstract
A correlation between the mechanical properties of cells and various diseases has been emerging in recent years. Atomic force microscopy (AFM) has been widely used to measure a single cell's apparent Young's modulus by treating it as a fully elastic object. More recently, quantitative characterization of the complete viscoelasticity of single cells has become possible. We performed AFM-based nano-indentation experiments on hemocytes isolated from third instar larvae to determine their viscoelasticity and found that live hemocytes, like many other cells, follow a scale-free power-law rheology (PLR) akin to soft glasses. Further, we examined the changes in the rheological response of hemocytes in the presence of pathogenic protein aggregates known to cause neurodegenerative diseases such as Huntington's disorder and amyotrophic lateral sclerosis. Our results show that cells lose their fluidity and appear more solid-like in the presence of certain aggregates, in a manner correlated to actin reorganization. More solid-like cells also display reduced intracellular transport through clathrin-mediated endocytosis (CME). However, the cell's rheology remains largely unaffected and is similar to that of wild-type (WT) hemocytes, if aggregates do not perturb the actin organization and CME. Moreover, the fluid-like nature was significantly recovered when actin organization was rescued by overexpressing specific actin interacting proteins or chaperones. Our study, for the first time, underscores a direct correlation between parameters governing glassy dynamics, actin organization and CME.
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Affiliation(s)
- Shatruhan Singh Rajput
- Department of Physics, Indian Institute of Science Education and Research, Pune 411008, India
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, UK
| | - Surya Bansi Singh
- National Centre for Cell Science, SP Pune University Campus, Pune 411007, India.
- SP Pune University, Pune 411007, India
| | - Deepa Subramanyam
- National Centre for Cell Science, SP Pune University Campus, Pune 411007, India.
| | - Shivprasad Patil
- Department of Physics, Indian Institute of Science Education and Research, Pune 411008, India.
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2
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Wu MC, Yu HW, Chen YQ, Ou MH, Serrano R, Huang GL, Wang YK, Lin KH, Fan YJ, Wu CC, Del Álamo JC, Chiou A, Chien S, Kuo JC. Early committed polarization of intracellular tension in response to cell shape determines the osteogenic differentiation of mesenchymal stromal cells. Acta Biomater 2023; 163:287-301. [PMID: 36328121 PMCID: PMC11389728 DOI: 10.1016/j.actbio.2022.10.052] [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: 04/15/2022] [Revised: 10/24/2022] [Accepted: 10/25/2022] [Indexed: 11/07/2022]
Abstract
Within the heterogeneous tissue architecture, a comprehensive understanding of how cell shapes regulate cytoskeletal mechanics by adjusting focal adhesions (FAs) signals to correlate with the lineage commitment of mesenchymal stromal cells (MSCs) remains obscure. Here, via engineered extracellular matrices, we observed that the development of mature FAs, coupled with a symmetrical pattern of radial fiber bundles, appeared at the right-angle vertices in cells with square shape. While circular cells aligned the transverse fibers parallel to the cell edge, and moved them centripetally in a counter-clockwise direction, symmetrical bundles of radial fibers at the vertices of square cells disrupted the counter-clockwise swirling and bridged the transverse fibers to move centripetally. In square cells, the contractile force, generated by the myosin IIA-enriched transverse fibers, were concentrated and transmitted outwards along the symmetrical bundles of radial fibers, to the extracellular matrix through FAs, and thereby driving FA organization and maturation. The symmetrical radial fiber bundles concentrated the transverse fibers contractility inward to the linkage between the actin cytoskeleton and the nuclear envelope. The tauter cytoskeletal network adjusted the nuclear-actomyosin force balance to cause nuclear deformability and to increase nuclear translocation of the transcription co-activator YAP, which in turn modulated the switch in MSC commitment. Thus, FAs dynamically respond to geometric cues and remodel actin cytoskeletal network to re-distribute intracelluar tension towards the cell nucleus, and thereby controlling YAP mechanotransduction signaling in regulating MSC fate decision. STATEMENT OF SIGNIFICANCE: We decipher how cellular mechanics is self-organized depending on extracellular geometric features to correlate with mesenchymal stromal cell lineage commitment. In response to geometry constrains on cell morphology, symmetrical radial fiber bundles are assembled and clustered depending on the maturation state of focal adhesions and bridge with the transverse fibers, and thereby establishing the dynamic cytoskeletal network. Contractile force, generated by the myosin-IIA-enriched transverse fibers, is transmitted and dynamically drives the retrograde movement of the actin cytoskeletal network, which appropriately adjusts the nuclear-actomyosin force balance and deforms the cell nucleus for YAP mechano-transduction signaling in regulating mesenchymal stromal cell fate decision.
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Affiliation(s)
- Ming-Chung Wu
- Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan
| | - Helen Wenshin Yu
- Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan; Institute of Biophotonics, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan
| | - Yin-Quan Chen
- Cancer Progression Research Center, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan
| | - Meng-Hsin Ou
- Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan
| | - Ricardo Serrano
- Department of Bioengineering and Institute of Engineering in Medicine, University of California at San Diego, La Jolla, CA 92093, USA; Department of Mechanical and Aerospace Engineering, University of California at San Diego, La Jolla, CA 92093, USA; Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Guan-Lin Huang
- Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan
| | - Yang-Kao Wang
- Department of Cell Biology and Anatomy, National Cheng Kung University, Tainan, 70101, Taiwan
| | - Kung-Hui Lin
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - Yu-Jui Fan
- School of Biomedical Engineering, Taipei Medical University, Taipei 110, Taiwan
| | - Chi-Chang Wu
- Department of Electronic Engineering, National Chin-Yi University of Technology, Taichung 411030, Taiwan
| | - Juan C Del Álamo
- Department of Bioengineering and Institute of Engineering in Medicine, University of California at San Diego, La Jolla, CA 92093, USA; Department of Mechanical and Aerospace Engineering, University of California at San Diego, La Jolla, CA 92093, USA; Center for Cardiovascular Biology, University of Washington, School of Medicine, Seattle, WA, 98109, USA; Mechanical Engineering Department, University of Washington, Seattle, WA, 98195, USA
| | - Arthur Chiou
- Institute of Biophotonics, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan
| | - Shu Chien
- Department of Bioengineering and Institute of Engineering in Medicine, University of California at San Diego, La Jolla, CA 92093, USA
| | - Jean-Cheng Kuo
- Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan; Cancer Progression Research Center, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan.
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3
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Aifuwa I, Kim BC, Kamat P, Starich B, Agrawal A, Tanrioven D, Luperchio TR, Valencia AMJ, Perestrelo T, Reddy K, Ha T, Philip JM. Senescent stroma induces nuclear deformations in cancer cells via the inhibition of RhoA/ROCK/myosin II-based cytoskeletal tension. PNAS NEXUS 2023; 2:pgac270. [PMID: 36712940 PMCID: PMC9830950 DOI: 10.1093/pnasnexus/pgac270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 12/02/2022] [Indexed: 06/18/2023]
Abstract
The presence of senescent cells within tissues has been functionally linked to malignant transformations. Here, using tension-gauge tethers technology, particle-tracking microrheology, and quantitative microscopy, we demonstrate that senescent-associated secretory phenotype (SASP) derived from senescent fibroblasts impose nuclear lobulations and volume shrinkage on malignant cells, which stems from the loss of RhoA/ROCK/myosin II-based cortical tension. This loss in cytoskeletal tension induces decreased cellular contractility, adhesion, and increased mechanical compliance. These SASP-induced morphological changes are, in part, mediated by Lamin A/C. These findings suggest that SASP induces defective outside-in mechanotransduction from actomyosin fibers in the cytoplasm to the nuclear lamina, thereby triggering a cascade of biophysical and biomolecular changes in cells that associate with malignant transformations.
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Affiliation(s)
- Ivie Aifuwa
- Johns Hopkins Physical Sciences - Oncology Center, Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Byoung Choul Kim
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
- Division of Nano-Bioengineering, Incheon National University, Incheon 22012, South Korea
| | - Pratik Kamat
- Johns Hopkins Physical Sciences - Oncology Center, Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Bartholomew Starich
- Johns Hopkins Physical Sciences - Oncology Center, Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Anshika Agrawal
- Johns Hopkins Physical Sciences - Oncology Center, Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Derin Tanrioven
- Johns Hopkins Physical Sciences - Oncology Center, Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Teresa R Luperchio
- Department of Biological Chemistry, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Angela M Jimenez Valencia
- Johns Hopkins Physical Sciences - Oncology Center, Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Tania Perestrelo
- Johns Hopkins Physical Sciences - Oncology Center, Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Karen Reddy
- Department of Biological Chemistry, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Taekjip Ha
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
- Howard Hughes Medical Institute, Baltimore, MD 21205, USA
| | - Jude M Philip
- Johns Hopkins Physical Sciences - Oncology Center, Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Oncology, Sidney Kimmel Cancer Center, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
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4
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Wang Z, Wang X, Zhang Y, Xu W, Han X. Principles and Applications of Single Particle Tracking in Cell Research. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2005133. [PMID: 33533163 DOI: 10.1002/smll.202005133] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 11/24/2020] [Indexed: 06/12/2023]
Abstract
It is a tough challenge for many decades to decipher the complex relationships between cell behaviors and cellular physical properties. Single particle tracking (SPT) with high spatial and temporal resolution has been applied extensively in cell research to understand physicochemical properties of cells and their bio-functions by tracking endogenous or exogenous probes. This review describes the fundamental principles of SPT as well as its applications in intracellular mechanics, membrane dynamics, organelles distribution, and processes of internalization and transport. Finally, challenges and future directions of SPT are also discussed.
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Affiliation(s)
- Zhao Wang
- State Key Laboratory of Urban Water Resource and Environment, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, China
| | - Xuejing Wang
- College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, 310058, China
| | - Ying Zhang
- School of Materials and Chemical Engineering, Heilongjiang Institute of Technology, Harbin, 150027, China
| | - Weili Xu
- State Key Laboratory of Urban Water Resource and Environment, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, China
| | - Xiaojun Han
- State Key Laboratory of Urban Water Resource and Environment, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, China
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5
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Dawson MR, Xuan B, Hsu J, Ghosh D. Force balancing ACT-IN the tumor microenvironment: Cytoskeletal modifications in cancer and stromal cells to promote malignancy. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2020; 360:1-31. [PMID: 33962748 DOI: 10.1016/bs.ircmb.2020.09.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The tumor microenvironment is a complex milieu that dictates the growth, invasion, and metastasis of cancer cells. Both cancer and stromal cells in the tumor tissue encounter and adapt to a variety of extracellular factors, and subsequently contribute and drive the progression of the disease to more advanced stages. As the disease progresses, a small population of cancer cells becomes more invasive through a complex process known as epithelial-mesenchymal transition, and nearby stromal cells assume a carcinoma associated fibroblast phenotype characterized by enhanced migration, cell contractility, and matrix secretion with the ability to reorganize extracellular matrices. As cells transition into more malignant phenotypes their biophysical properties, controlled by the organization of cytoskeletal proteins, are altered. Actin and its associated proteins are essential modulators and facilitators of these changes. As the cells respond to the cues in the microenvironment, actin driven mechanical forces inside and outside the cells also evolve. Recent advances in biophysical techniques have enabled us to probe these actin driven changes in cancer and stromal cells and demarcate their role in driving changes in the microenvironment. Understanding the underlying biophysical mechanisms that drive cancer progression could provide critical insight on novel therapeutic approaches in the fight against cancer.
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Affiliation(s)
- Michelle R Dawson
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Brown University, Providence, RI, United States; Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, United States; Brown University, Center for Biomedical Engineering, Providence, RI, United States.
| | - Botai Xuan
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Brown University, Providence, RI, United States
| | - Jeffrey Hsu
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Brown University, Providence, RI, United States
| | - Deepraj Ghosh
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Brown University, Providence, RI, United States
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6
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Hafner J, Oelschlaeger C, Willenbacher N. Microrheology imaging of fiber suspensions - a case study for lyophilized collagen I in HCl solutions. SOFT MATTER 2020; 16:9014-9027. [PMID: 32821895 DOI: 10.1039/d0sm01096k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In fiber suspensions with low optical contrast, the in situ characterization of structural properties with conventional microscopy methods fails. However, overlaying subsequent images of multiple particle tracking (MPT) videos including short trajectories usually discarded in MPT analysis allowed for direct visualization of individual fibers and the network structure of lyophilized collagen I (Coll) distributed in hydrochloric acid solutions. MPT yielded a broad distribution of mean square displacements (MSDs). Freely diffusing tracer particles yielded viscosities indicating that, irrespective of concentration, a constant amount of Coll is dissolved in the aqueous phase. Particles found elastically trapped within fibrous Coll structures exhibited a broad range of time-independent MSDs and we propose a structure comprising multiple fiber bundles with dense regions inaccessible to tracers and elastic regions of different stiffness in between. Bulky aggregates inaccessible to the 0.2 μm tracers exist even at low Coll concentrations, a network of slender fibers evolves above the sol-gel transition and these fibers densify with increasing Coll concentration. This novel MPT-based imaging technique possesses great potential to characterize the fiber distribution in and structural properties of a broad range of biological and technical suspensions showing low contrast when imaged with conventional techniques. Thus, MPT imaging and microrheology will help to better understand the effect of fiber distribution and network structure on the viscoelastic properties of complex suspensions.
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Affiliation(s)
- Johanna Hafner
- Department of Mechanical Engineering and Mechanics, Applied Mechanics Group, Karlsruhe Institute of Technology, Karlsruhe, Germany.
| | - Claude Oelschlaeger
- Department of Mechanical Engineering and Mechanics, Applied Mechanics Group, Karlsruhe Institute of Technology, Karlsruhe, Germany.
| | - Norbert Willenbacher
- Department of Mechanical Engineering and Mechanics, Applied Mechanics Group, Karlsruhe Institute of Technology, Karlsruhe, Germany.
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7
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Agarwal M, Biswas P, Bhattacharya A, Sinha DK. Reactive oxygen species-mediated cytoplasmic stiffening impairs the phagocytic ability of the macrophage. J Cell Sci 2020; 133:jcs.236471. [PMID: 32005700 DOI: 10.1242/jcs.236471] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 01/17/2020] [Indexed: 12/12/2022] Open
Abstract
The phagocytic ability of macrophages empowers them to enforce innate immunity. RAW264.7, THP-1 and peripheral blood mononuclear cell-derived macrophages display considerable variability with regards to their phagocytic ability. We identify the underlying causes that attenuate the phagocytic abilities of a macrophage. Deformability of the cytoplasm and cortex influences the macrophage's phagocytic ability, and macrophages use the large cell-to-cell variability of their cytoplasmic stiffness to modulate their phagocytic ability. We find that the more-deformable macrophages have a higher phagocytic ability than those that are less deformable. Further, the subcellular spatial variability of cortex stiffness gives rise to more-deformable subdomains on the membrane for pathogen ingestion. We report a previously unknown negative-feedback loop that is triggered by the phagocytic oxidative burst. Macrophages utilize the excess reactive oxygen species to stiffen the cytoplasm, reducing their phagocytic propensity. In organisms, ageing or pathological conditions impair the phagocytic ability of macrophages. Our findings identify the targets that could potentially be utilized for restoring the phagocytic ability of the defunct macrophages.
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Affiliation(s)
- Mahesh Agarwal
- School of Biological Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 32, India
| | - Parijat Biswas
- School of Biological Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 32, India
| | - Anindita Bhattacharya
- School of Biological Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 32, India
| | - Deepak Kumar Sinha
- School of Biological Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 32, India
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8
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Martinac B, Nikolaev YA, Silvani G, Bavi N, Romanov V, Nakayama Y, Martinac AD, Rohde P, Bavi O, Cox CD. Cell membrane mechanics and mechanosensory transduction. CURRENT TOPICS IN MEMBRANES 2020; 86:83-141. [DOI: 10.1016/bs.ctm.2020.08.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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9
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Schierbaum N, Rheinlaender J, Schäffer TE. Combined atomic force microscopy (AFM) and traction force microscopy (TFM) reveals a correlation between viscoelastic material properties and contractile prestress of living cells. SOFT MATTER 2019; 15:1721-1729. [PMID: 30657157 DOI: 10.1039/c8sm01585f] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Living cells exhibit a complex mechanical behavior, whose underlying mechanisms are still largely unknown. Emerging from the molecular structure and dynamics of the cytoskeleton, the mechanical behavior comprises "passive" viscoelastic material properties and "active" contractile prestress. To directly investigate the connection between these quantities at the single-cell level, we here present the combination of atomic force microscopy (AFM) with traction force microscopy (TFM). With this combination, we simultaneously measure viscoelastic material parameters (stiffness, fluidity) and contractile prestress of adherent fibroblast and epithelial cells. Although stiffness, fluidity, and contractile prestress greatly vary within a cell population, they are highly correlated: stiffer cells have a lower fluidity and a larger prestress than softer cells. We show that viscoelastic material properties and contractile prestress are both governed by the activity of the actomyosin machinery. Our results underline the connection between a cell's viscoelastic material properties and its contractile prestress and their importance in cell mechanics.
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Affiliation(s)
- Nicolas Schierbaum
- Institute of Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany.
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10
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Lee G, Han SB, Lee JH, Kim HW, Kim DH. Cancer Mechanobiology: Microenvironmental Sensing and Metastasis. ACS Biomater Sci Eng 2019; 5:3735-3752. [PMID: 33405888 DOI: 10.1021/acsbiomaterials.8b01230] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The cellular microenvironment plays an important role in regulating cancer progress. Cancer can physically and chemically remodel its surrounding extracellular matrix (ECM). Critical cellular behaviors such as recognition of matrix geometry and rigidity, cell polarization and motility, cytoskeletal reorganization, and proliferation can be changed as a consequence of these ECM alternations. Here, we present an overview of cancer mechanobiology in detail, focusing on cancer microenvironmental sensing of exogenous cues and quantification of cancer-substrate interactions. In addition, mechanics of metastasis classified with tumor progression will be discussed. The mechanism underlying cancer mechanosensation and tumor progression may provide new insights into therapeutic strategies to alleviate cancer malignancy.
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Affiliation(s)
- GeonHui Lee
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, South Korea
| | - Seong-Beom Han
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, South Korea
| | - Jung-Hwan Lee
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan 31116, South Korea.,Department of Biomaterials Science, College of Dentistry, Dankook University, Cheonan 31116, South Korea
| | - Hae-Won Kim
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan 31116, South Korea.,Department of Biomaterials Science, College of Dentistry, Dankook University, Cheonan 31116, South Korea.,Department of Nanobiomedical Science and BK21 PLUS Global Research Center for Regenerative Medicine, Dankook University, Cheonan 31116, South Korea
| | - Dong-Hwee Kim
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, South Korea
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11
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Xuan B, Ghosh D, Cheney EM, Clifton EM, Dawson MR. Dysregulation in Actin Cytoskeletal Organization Drives Increased Stiffness and Migratory Persistence in Polyploidal Giant Cancer Cells. Sci Rep 2018; 8:11935. [PMID: 30093656 PMCID: PMC6085392 DOI: 10.1038/s41598-018-29817-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 07/16/2018] [Indexed: 02/06/2023] Open
Abstract
Polyploidal giant cancer cells (PGCCs) have been observed by pathologists in patient tumor samples and are especially prominent in late stage, high grade disease or after chemotherapy. However, they are often overlooked due to their apparent dormancy. Recent research has shown PGCCs to be chemoresistant and express stem-like features, traits associated with disease progression and relapse. Here, we show the preferential survival of PGCCs during Paclitaxel (PTX) treatment and used multiple particle tracking analysis to probe their unique biophysical phenotype. We show that PGCCs have higher inherent cytoplasmic and nuclear stiffness in order to withstand the mechanical stress associated with their increased size and the chemical stress from PTX treatment. Inhibitor studies show the involvement of a dysregulated RhoA-Rock1 pathway and overall actin cytoskeletal network as the underlying mechanism for the altered biophysical phenotype of PGCCs. Furthermore, PGCCs exhibit a slow but persistent migratory phenotype, a trait commonly associated with metastatic dissemination and invasiveness. This work demonstrates the clinical relevance and the need to study this subpopulation, in order to devise therapeutic strategies to combat disease relapse. By highlighting the unique biophysical phenotype of PGCCs, we hope to provide unique avenues for therapeutic targeting of these cells in disease treatment.
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Affiliation(s)
- Botai Xuan
- Brown University, Department of Molecular Pharmacology, Physiology, and Biotechnology, Providence, 02912, USA
| | - Deepraj Ghosh
- Brown University, Department of Molecular Pharmacology, Physiology, and Biotechnology, Providence, 02912, USA
| | - Emily M Cheney
- Brown University, Department of Molecular Pharmacology, Physiology, and Biotechnology, Providence, 02912, USA
| | - Elizabeth M Clifton
- Brown University, Department of Molecular Pharmacology, Physiology, and Biotechnology, Providence, 02912, USA
| | - Michelle R Dawson
- Brown University, Department of Molecular Pharmacology, Physiology, and Biotechnology, Providence, 02912, USA.
- Brown University, Center for Biomedical Engineering, Providence, 02912, USA.
- Brown University, School of Engineering, Providence, 02912, USA.
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12
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Wu PH, Aroush DRB, Asnacios A, Chen WC, Dokukin ME, Doss BL, Durand-Smet P, Ekpenyong A, Guck J, Guz NV, Janmey PA, Lee JSH, Moore NM, Ott A, Poh YC, Ros R, Sander M, Sokolov I, Staunton JR, Wang N, Whyte G, Wirtz D. A comparison of methods to assess cell mechanical properties. Nat Methods 2018; 15:491-498. [PMID: 29915189 DOI: 10.1038/s41592-018-0015-1] [Citation(s) in RCA: 377] [Impact Index Per Article: 62.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 12/11/2017] [Indexed: 01/06/2023]
Abstract
The mechanical properties of cells influence their cellular and subcellular functions, including cell adhesion, migration, polarization, and differentiation, as well as organelle organization and trafficking inside the cytoplasm. Yet reported values of cell stiffness and viscosity vary substantially, which suggests differences in how the results of different methods are obtained or analyzed by different groups. To address this issue and illustrate the complementarity of certain approaches, here we present, analyze, and critically compare measurements obtained by means of some of the most widely used methods for cell mechanics: atomic force microscopy, magnetic twisting cytometry, particle-tracking microrheology, parallel-plate rheometry, cell monolayer rheology, and optical stretching. These measurements highlight how elastic and viscous moduli of MCF-7 breast cancer cells can vary 1,000-fold and 100-fold, respectively. We discuss the sources of these variations, including the level of applied mechanical stress, the rate of deformation, the geometry of the probe, the location probed in the cell, and the extracellular microenvironment.
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Affiliation(s)
- Pei-Hsun Wu
- Department of Chemical and Biomolecular Engineering and Departments of Pathology and Oncology, The Johns Hopkins University and Johns Hopkins School of Medicine, Baltimore, MD, USA.
| | - Dikla Raz-Ben Aroush
- Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Atef Asnacios
- Laboratoire Matière et Systèmes Complexes, Unité Mixte de Recherche 7057, Centre National de la Recherche Scientifique (CNRS) and Université Paris-Diderot (Paris 7), Sorbonne Paris Cité, Paris, France.
| | - Wei-Chiang Chen
- Department of Chemical and Biomolecular Engineering and Departments of Pathology and Oncology, The Johns Hopkins University and Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Maxim E Dokukin
- Department of Mechanical Engineering, Tufts University, Medford, MA, USA
| | - Bryant L Doss
- Department of Physics, Arizona State University, Tempe, AZ, USA
| | - Pauline Durand-Smet
- Laboratoire Matière et Systèmes Complexes, Unité Mixte de Recherche 7057, Centre National de la Recherche Scientifique (CNRS) and Université Paris-Diderot (Paris 7), Sorbonne Paris Cité, Paris, France
| | - Andrew Ekpenyong
- Biotechnology Center, Technische Universität Dresden, Dresden, Germany
| | - Jochen Guck
- Biotechnology Center, Technische Universität Dresden, Dresden, Germany.
| | - Nataliia V Guz
- Department of Physics, Clarkson University, Potsdam, NY, USA
| | - Paul A Janmey
- Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA, USA.
| | - Jerry S H Lee
- Department of Chemical and Biomolecular Engineering and Departments of Pathology and Oncology, The Johns Hopkins University and Johns Hopkins School of Medicine, Baltimore, MD, USA.,Center for Strategic Scientific Initiatives, National Cancer Institute, Bethesda, MD, USA
| | - Nicole M Moore
- Department of Mechanical Science and Engineering, College of Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Albrecht Ott
- Biological Experimental Physics Department, Saarland University, Saarbruecken, Germany.
| | - Yeh-Chuin Poh
- Department of Mechanical Science and Engineering, College of Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Robert Ros
- Department of Physics, Arizona State University, Tempe, AZ, USA.
| | - Mathias Sander
- Biological Experimental Physics Department, Saarland University, Saarbruecken, Germany
| | - Igor Sokolov
- Department of Mechanical Engineering, Tufts University, Medford, MA, USA.
| | - Jack R Staunton
- Department of Physics, Arizona State University, Tempe, AZ, USA
| | - Ning Wang
- Department of Mechanical Science and Engineering, College of Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
| | - Graeme Whyte
- Biotechnology Center, Technische Universität Dresden, Dresden, Germany
| | - Denis Wirtz
- Department of Chemical and Biomolecular Engineering and Departments of Pathology and Oncology, The Johns Hopkins University and Johns Hopkins School of Medicine, Baltimore, MD, USA.
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13
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Musashi-1 Enhances Glioblastoma Cell Migration and Cytoskeletal Dynamics through Translational Inhibition of Tensin3. Sci Rep 2017; 7:8710. [PMID: 28821879 PMCID: PMC5562834 DOI: 10.1038/s41598-017-09504-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 07/26/2017] [Indexed: 01/11/2023] Open
Abstract
The RNA-binding protein Musashi-1 (MSI1) exerts essential roles in multiple cellular functions, such as maintenance of self-renewal and pluripotency of stem cells. MSI1 overexpression has been observed in several tumor tissues, including glioblastoma (GBM), and is considered as a well-established marker for tumor metastasis and recurrence. However, the molecular mechanisms by which MSI1 regulates cell migration are still undetermined. Here we reported that MSI1 alters cell morphology, promotes cell migration, and increases viscoelasticity of GBM cells. We also found that MSI1 directly binds to the 3′UTR of Tensin 3 (TNS3) mRNA, a negative regulator of cell migration, to inhibit its translation. Additionally, we identified that RhoA-GTP could be a potential regulator in MSI1/TNS3-mediated cell migration and morphological changes. In a xenograft animal model, high expression ratio of MSI1 to TNS3 enhanced GBM tumor migration. We also confirmed that MSI1 and TNS3 expressions are mutually exclusive in migratory tumor lesions, and GBM patients with MSI1high/TNS3low pattern tend to have poor clinical outcome. Taken together, our findings suggested a critical role of MSI1-TNS3 axis in regulating GBM migration and highlighted that the ratio of MSI1/TNS3 could predict metastatic and survival outcome of GBM patients.
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14
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Probing cytoskeletal modulation of passive and active intracellular dynamics using nanobody-functionalized quantum dots. Nat Commun 2017; 8:14772. [PMID: 28322225 PMCID: PMC5364406 DOI: 10.1038/ncomms14772] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 01/27/2017] [Indexed: 11/08/2022] Open
Abstract
The cytoplasm is a highly complex and heterogeneous medium that is structured by the cytoskeleton. How local transport depends on the heterogeneous organization and dynamics of F-actin and microtubules is poorly understood. Here we use a novel delivery and functionalization strategy to utilize quantum dots (QDs) as probes for active and passive intracellular transport. Rapid imaging of non-functionalized QDs reveals two populations with a 100-fold difference in diffusion constant, with the faster fraction increasing upon actin depolymerization. When nanobody-functionalized QDs are targeted to different kinesin motor proteins, their trajectories do not display strong actin-induced transverse displacements, as suggested previously. Only kinesin-1 displays subtle directional fluctuations, because the subset of microtubules used by this motor undergoes prominent undulations. Using actin-targeting agents reveals that F-actin suppresses most microtubule shape remodelling, rather than promoting it. These results demonstrate how the spatial heterogeneity of the cytoskeleton imposes large variations in non-equilibrium intracellular dynamics.
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15
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Mapping intracellular mechanics on micropatterned substrates. Proc Natl Acad Sci U S A 2016; 113:E7159-E7168. [PMID: 27799529 DOI: 10.1073/pnas.1605112113] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The mechanical properties of cells impact on their architecture, their migration, intracellular trafficking, and many other cellular functions and have been shown to be modified during cancer progression. We have developed an approach to map the intracellular mechanical properties of living cells by combining micropatterning and optical tweezers-based active microrheology. We optically trap micrometer-sized beads internalized in cells plated on crossbow-shaped adhesive micropatterns and track their displacement following a step displacement of the cell. The local intracellular complex shear modulus is measured from the relaxation of the bead position assuming that the intracellular microenvironment of the bead obeys power-law rheology. We also analyze the data with a standard viscoelastic model and compare with the power-law approach. We show that the shear modulus decreases from the cell center to the periphery and from the cell rear to the front along the polarity axis of the micropattern. We use a variety of inhibitors to quantify the spatial contribution of the cytoskeleton, intracellular membranes, and ATP-dependent active forces to intracellular mechanics and apply our technique to differentiate normal and cancer cells.
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16
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Elastic properties of epithelial cells probed by atomic force microscopy. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:3075-82. [PMID: 26193077 DOI: 10.1016/j.bbamcr.2015.07.010] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 06/30/2015] [Accepted: 07/10/2015] [Indexed: 12/21/2022]
Abstract
Cellular mechanics plays a crucial role in many biological processes such as cell migration, cell growth, embryogenesis, and oncogenesis. Epithelia respond to environmental cues comprising biochemical and physical stimuli through defined changes in cell elasticity. For instance, cells can differentiate between certain properties such as viscoelasticity or topography of substrates by adapting their own elasticity and shape. A living cell is a complex viscoelastic body that not only exhibits a shell architecture composed of a membrane attached to a cytoskeleton cortex but also generates contractile forces through its actomyosin network. Here we review cellular mechanics of single cells in the context of epithelial cell layers responding to chemical and physical stimuli. This article is part of a Special Issue entitled: Mechanobiology.
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17
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Iannone M, Ventre M, Formisano L, Casalino L, Patriarca EJ, Netti PA. Nanoengineered surfaces for focal adhesion guidance trigger mesenchymal stem cell self-organization and tenogenesis. NANO LETTERS 2015; 15:1517-1525. [PMID: 25699511 DOI: 10.1021/nl503737k] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The initial conditions for morphogenesis trigger a cascade of events that ultimately dictate structure and functions of tissues and organs. Here we report that surface nanopatterning can control the initial assembly of focal adhesions, hence guiding human mesenchymal stem cells (hMSCs) through the process of self-organization and differentiation. This process self-sustains, leading to the development of macroscopic tissues with molecular profiles and microarchitecture reminiscent of embryonic tendons. Therefore, material surfaces can be in principle engineered to set off the hMSC program toward tissuegenesis in a deterministic manner by providing adequate sets of initial environmental conditions.
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Affiliation(s)
- Maria Iannone
- Center for Advanced Biomaterials for Healthcare@CRIB, Istituto Italiano di Tecnologia , Largo Barsanti e Matteucci 53, 80125 Naples, Italy
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18
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Yu HW, Chen YQ, Huang CM, Liu CY, Chiou A, Wang YK, Tang MJ, Kuo JC. β-PIX controls intracellular viscoelasticity to regulate lung cancer cell migration. J Cell Mol Med 2015; 19:934-47. [PMID: 25683605 PMCID: PMC4420597 DOI: 10.1111/jcmm.12441] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 08/22/2014] [Indexed: 01/08/2023] Open
Abstract
Cancer metastasis occurs via a progress involving abnormal cell migration. Cell migration, a dynamic physical process, is controlled by the cytoskeletal system, which includes the dynamics of actin organization and cellular adhesive organelles, focal adhesions (FAs). However, it is not known whether the organization of actin cytoskeletal system has a regulatory role in the physiologically relevant aspects of cancer metastasis. In the present studies, it was found that lung adenocarcinoma cells isolated from the secondary lung cancer of the lymph nodes, H1299 cells, show specific dynamics in terms of the actin cytoskeleton and FAs. This results in a higher level of mobility and this is regulated by an immature FA component, β-PIX (PAK-interacting exchange factor-β). In H1299 cells, β-PIX's activity was found not to be down-regulated by sequestration onto stress fibres, as the cells did not bundle actin filaments into stress fibres. Thus, β-PIX mainly remained localized at FAs, which allowed maturation of nascent adhesions into focal complexes; this resulted in actin polymerization, increased actin network integrity, changes in the intracellular microrheology at the peripheral of the cell, and cell polarity, which in turn regulated cell migration. Perturbation of β-PIX caused an inhibition of cell migration, including migration velocity, accumulated distance and directional persistence. Our results demonstrate the importance of β-PIX to the regulation of high mobility of lung adenocarcinoma cell line H1299 and that this occurs via regulation of FA dynamics, changes in actin cytoskeleton organization and cell polarity.
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Affiliation(s)
- Helen Wenshin Yu
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan
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19
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Cribb J, Osborne LD, Hsiao JPL, Vicci L, Meshram A, O'Brien ET, Spero RC, Taylor R, Superfine R. A high throughput array microscope for the mechanical characterization of biomaterials. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2015; 86:023711. [PMID: 25725856 PMCID: PMC4344474 DOI: 10.1063/1.4907705] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 01/26/2015] [Indexed: 05/24/2023]
Abstract
In the last decade, the emergence of high throughput screening has enabled the development of novel drug therapies and elucidated many complex cellular processes. Concurrently, the mechanobiology community has developed tools and methods to show that the dysregulation of biophysical properties and the biochemical mechanisms controlling those properties contribute significantly to many human diseases. Despite these advances, a complete understanding of the connection between biomechanics and disease will require advances in instrumentation that enable parallelized, high throughput assays capable of probing complex signaling pathways, studying biology in physiologically relevant conditions, and capturing specimen and mechanical heterogeneity. Traditional biophysical instruments are unable to meet this need. To address the challenge of large-scale, parallelized biophysical measurements, we have developed an automated array high-throughput microscope system that utilizes passive microbead diffusion to characterize mechanical properties of biomaterials. The instrument is capable of acquiring data on twelve-channels simultaneously, where each channel in the system can independently drive two-channel fluorescence imaging at up to 50 frames per second. We employ this system to measure the concentration-dependent apparent viscosity of hyaluronan, an essential polymer found in connective tissue and whose expression has been implicated in cancer progression.
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Affiliation(s)
- Jeremy Cribb
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, 345 Chapman Hall, CB #3255, Chapel Hill, North Carolina 27599, USA
| | - Lukas D Osborne
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, 345 Chapman Hall, CB #3255, Chapel Hill, North Carolina 27599, USA
| | - Joe Ping-Lin Hsiao
- Department of Computer Science, University of North Carolina at Chapel Hill, Sitterson Hall, CB #3175, Chapel Hill, North Carolina 27599, USA
| | - Leandra Vicci
- Department of Computer Science, University of North Carolina at Chapel Hill, Sitterson Hall, CB #3175, Chapel Hill, North Carolina 27599, USA
| | - Alok Meshram
- Department of Computer Science, University of North Carolina at Chapel Hill, Sitterson Hall, CB #3175, Chapel Hill, North Carolina 27599, USA
| | - E Tim O'Brien
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, 345 Chapman Hall, CB #3255, Chapel Hill, North Carolina 27599, USA
| | - Richard Chasen Spero
- Rheomics Inc., B40 Chapman Hall CB #3255, Chapel Hill, North Carolina 27599, USA
| | - Russell Taylor
- Department of Computer Science, University of North Carolina at Chapel Hill, Sitterson Hall, CB #3175, Chapel Hill, North Carolina 27599, USA
| | - Richard Superfine
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, 345 Chapman Hall, CB #3255, Chapel Hill, North Carolina 27599, USA
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20
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Chen YQ, Su PT, Chen YH, Wei MT, Huang CH, Osterday K, del Álamo JC, Syu WJ, Chiou A. The effect of enterohemorrhagic E. coli infection on the cell mechanics of host cells. PLoS One 2014; 9:e112137. [PMID: 25369259 PMCID: PMC4219835 DOI: 10.1371/journal.pone.0112137] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 10/13/2014] [Indexed: 11/18/2022] Open
Abstract
Enterohaemorrhagic E. coli (EHEC) is a type of human pathogenic bacteria. The main virulence characteristics of EHEC include the formation of attaching and effacing lesions (A/E lesions) and the production of one or more Shiga-like toxins, which may induce human uremic complications. When EHEC infects host cells, it releases translocated intimin receptor (Tir) and effector proteins inside the host cells, inducing the rearrangement and accumulation of the F-actin cytoskeleton, a phenotype leading to the formation of pedestals in the apical cell surface, and the growth of stress fibers at the base of the cells. To examine the effect of EHEC infection on cell mechanics, we carried out a series of experiments to examine HeLa cells with and without EHEC infection to quantify the changes in (1) focal adhesion area, visualized by anti-vinculin staining; (2) the distribution and orientation of stress fibers; and (3) the intracellular viscoelasticity, via directional video particle tracking microrheology. Our results indicated that in EHEC-infected HeLa cells, the focal adhesion area increased and the actin stress fibers became thicker and more aligned. The cytoskeletal reorganization induced by EHEC infection mediated a dramatic increase in the cytoplasmic elastic shear modulus of the infected cells, and a transition in the viscoelastic behavior of the cells from viscous-like to elastic-like. These changes in mechanobiological characteristics might modulate the attachments between EHEC and the host cell to withstand exfoliation, and between the host cell and the extracellular matrix, and might also alter epithelial integrity.
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Affiliation(s)
- Yin-Quan Chen
- Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan, Republic of China
| | - Pin-Tzu Su
- Institute of Microbiology & Immunology, National Yang-Ming University, Taipei, Taiwan, Republic of China
- Biophotonics & Molecular Imaging Research Center (BMIRC), National Yang-Ming University, Taipei, Taiwan, Republic of China
| | - Yu-Hsuan Chen
- Institute of Microbiology & Immunology, National Yang-Ming University, Taipei, Taiwan, Republic of China
| | - Ming-Tzo Wei
- Bioengineering Program, Lehigh University, Bethlehem, PA, United States of America
| | - Chien-Hsiu Huang
- Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan, Republic of China
| | - Kathryn Osterday
- Department of Mechanical and Aerospace Engineering, San Diego, California, United States of America
| | - Juan C. del Álamo
- Department of Mechanical and Aerospace Engineering, San Diego, California, United States of America
- Institute of Engineering in Medicine, University of California San Diego, San Diego, California, United States of America
- * E-mail: (JCA); (WJS); (AC)
| | - Wan-Jr Syu
- Institute of Microbiology & Immunology, National Yang-Ming University, Taipei, Taiwan, Republic of China
- Biophotonics & Molecular Imaging Research Center (BMIRC), National Yang-Ming University, Taipei, Taiwan, Republic of China
- * E-mail: (JCA); (WJS); (AC)
| | - Arthur Chiou
- Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan, Republic of China
- Biophotonics & Molecular Imaging Research Center (BMIRC), National Yang-Ming University, Taipei, Taiwan, Republic of China
- * E-mail: (JCA); (WJS); (AC)
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21
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Moeendarbary E, Harris AR. Cell mechanics: principles, practices, and prospects. WILEY INTERDISCIPLINARY REVIEWS. SYSTEMS BIOLOGY AND MEDICINE 2014; 6:371-88. [PMID: 25269160 PMCID: PMC4309479 DOI: 10.1002/wsbm.1275] [Citation(s) in RCA: 156] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cells generate and sustain mechanical forces within their environment as part of their normal physiology. They are active materials that can detect mechanical stimulation by the activation of mechanosensitive signaling pathways, and respond to physical cues through cytoskeletal re-organization and force generation. Genetic mutations and pathogens that disrupt the cytoskeletal architecture can result in changes to cell mechanical properties such as elasticity, adhesiveness, and viscosity. On the other hand, perturbations to the mechanical environment can affect cell behavior. These transformations are often a hallmark and symptom of a variety of pathologies. Consequently, there are now a myriad of experimental techniques and theoretical models adapted from soft matter physics and mechanical engineering to characterize cell mechanical properties. Interdisciplinary research combining modern molecular biology with advanced cell mechanical characterization techniques now paves the way for furthering our fundamental understanding of cell mechanics and its role in development, physiology, and disease. We describe a generalized outline for measuring cell mechanical properties including loading protocols, tools, and data interpretation.We summarize recent advances in the field and explain how cell biomechanics research can be adopted by physicists, engineers, biologists, and clinicians alike.
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Affiliation(s)
- Emad Moeendarbary
- Department of Physiology, Development and Neuroscience, University of CambridgeCambridge, UK
- Hughes Hall, University of CambridgeCambridge, UK
| | - Andrew R Harris
- Department of Bioengineering, University of California BerkeleyBerkeley, CA, USA
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22
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McAndrews KM, McGrail DJ, Quach ND, Dawson MR. Spatially coordinated changes in intracellular rheology and extracellular force exertion during mesenchymal stem cell differentiation. Phys Biol 2014; 11:056004. [PMID: 25156989 DOI: 10.1088/1478-3975/11/5/056004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The mechanical properties within the cell are regulated by the organization of the actin cytoskeleton, which is linked to the extracellular environment through focal adhesion proteins that transmit force. Chemical and mechanical stimuli alter the organization of cytoskeletal actin, which results in changes in cell shape, adhesion, and differentiation. By combining particle-tracking microrheology and traction force cytometry, we can monitor the mechanical properties of the actin meshwork and determine how changes in the intracellular network contribute to force generation. In this study, we investigated the effects of chemical (differentiation factors) and mechanical (substrate rigidity) stimuli important in mesenchymal stem cell (MSC) differentiation on the intracellular mechanics and traction stress generation. We found the presence of adipogenic factors resulted in stiffening of the actin meshwork regardless of substrate rigidity. In contrast, these factors increased traction stresses on hard substrates, which was associated with increased expression of contractility genes. Furthermore, MSCs cultured on hard substrates expressed both adipogenic and osteogenic markers indicative of mixed differentiation. On hard substrates, heterogeneity in the local elastic modulus-traction stress correlation was also increased in response to adipogenic factors, indicating that these mechanical properties may be reflective of differences in the level of MSC differentiation. These results suggest intracellular rheology and traction stress generation are spatially regulated and contribute insight into how single cell mechanical forces contribute to MSC differentiation.
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Affiliation(s)
- Kathleen M McAndrews
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
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23
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Guo M, Ehrlicher AJ, Jensen MH, Renz M, Moore JR, Goldman RD, Lippincott-Schwartz J, Mackintosh FC, Weitz DA. Probing the stochastic, motor-driven properties of the cytoplasm using force spectrum microscopy. Cell 2014; 158:822-832. [PMID: 25126787 PMCID: PMC4183065 DOI: 10.1016/j.cell.2014.06.051] [Citation(s) in RCA: 335] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 04/28/2014] [Accepted: 06/29/2014] [Indexed: 01/17/2023]
Abstract
Molecular motors in cells typically produce highly directed motion; however, the aggregate, incoherent effect of all active processes also creates randomly fluctuating forces, which drive diffusive-like, nonthermal motion. Here, we introduce force-spectrum-microscopy (FSM) to directly quantify random forces within the cytoplasm of cells and thereby probe stochastic motor activity. This technique combines measurements of the random motion of probe particles with independent micromechanical measurements of the cytoplasm to quantify the spectrum of force fluctuations. Using FSM, we show that force fluctuations substantially enhance intracellular movement of small and large components. The fluctuations are three times larger in malignant cells than in their benign counterparts. We further demonstrate that vimentin acts globally to anchor organelles against randomly fluctuating forces in the cytoplasm, with no effect on their magnitude. Thus, FSM has broad applications for understanding the cytoplasm and its intracellular processes in relation to cell physiology in healthy and diseased states.
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Affiliation(s)
- Ming Guo
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Allen J Ehrlicher
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA; Beth Israel Deaconess Medical Center, Boston, MA 02115, USA
| | - Mikkel H Jensen
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA; Department of Physiology and Biophysics, Boston University, Boston, MA 02118, USA
| | - Malte Renz
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jeffrey R Moore
- Department of Physiology and Biophysics, Boston University, Boston, MA 02118, USA
| | - Robert D Goldman
- Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Jennifer Lippincott-Schwartz
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | | | - David A Weitz
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA; Department of Physics, Harvard University, Cambridge, MA 02138, USA.
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24
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Chi Q, Yin T, Gregersen H, Deng X, Fan Y, Zhao J, Liao D, Wang G. Rear actomyosin contractility-driven directional cell migration in three-dimensional matrices: a mechano-chemical coupling mechanism. J R Soc Interface 2014; 11:20131072. [PMID: 24647903 DOI: 10.1098/rsif.2013.1072] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Cell migration is of vital importance in many biological processes, including organismal development, immune response and development of vascular diseases. For instance, migration of vascular smooth muscle cells from the media to intima is an essential part of the development of atherosclerosis and restenosis after stent deployment. While it is well characterized that cells use actin polymerization at the leading edge to propel themselves to move on two-dimensional substrates, the migration modes of cells in three-dimensional matrices relevant to in vivo environments remain unclear. Intracellular tension, which is created by myosin II activity, fulfils a vital role in regulating cell migration. We note that there is compelling evidence from theoretical and experimental work that myosin II accumulates at the cell rear, either isoform-dependent or -independent, leading to three-dimensional migration modes driven by posterior myosin II tension. The scenario is not limited to amoeboid migration, and it is also seen in mesenchymal migration in which a two-dimensional-like migration mode based on front protrusions is often expected, suggesting that there may exist universal underlying mechanisms. In this review, we aim to shed some light on how anisotropic myosin II localization induces cell motility in three-dimensional environments from a biomechanical view. We demonstrate an interesting mechanism where an interplay between mechanical myosin II recruitment and biochemical myosin II activation triggers directional migration in three-dimensional matrices. In the case of amoeboid three-dimensional migration, myosin II first accumulates at the cell rear to induce a slight polarization displayed as a uropod-like structure under the action of a tension-dependent mechanism. Subsequent biochemical signalling pathways initiate actomyosin contractility, producing traction forces on the adhesion system or creating prominent motile forces through blebbing activity, to drive cells to move. In mesenchymal three-dimensional migration, cells can also take advantage of the elastic properties of three-dimensional matrices to move. A minor myosin isoform, myosin IIB, is retained by relatively stiff three-dimensional matrices at the posterior side, then activated by signalling cascades, facilitating prominent cell polarization by establishing front-back polarity and creating cell rear. Myosin IIB initiates cell polarization and coordinates with the major isoform myosin IIA-assembled stress fibres, to power the directional migration of cells in the three-dimensional matrix.
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Affiliation(s)
- Qingjia Chi
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education; Chongqing Engineering Laboratory in Vascular Implants; Bioengineering College of Chongqing University, , Chongqing, People's Republic of China
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25
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Nampe D, Tsutsui H. Engineered micromechanical cues affecting human pluripotent stem cell regulations and fate. ACTA ACUST UNITED AC 2013; 18:482-93. [PMID: 24062363 DOI: 10.1177/2211068213503156] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The survival, growth, self-renewal, and differentiation of human pluripotent stem cells (hPSCs) are influenced by their microenvironment, or so-called "niche," consisting of particular chemical and physical cues. Previous studies on mesenchymal stem cells and other stem cells have collectively uncovered the importance of physical cues and have begun to shed light on how stem cells sense and process such cues. In an attempt to support similar progress in mechanobiology of hPSCs, we review mechanosensory machinery, which plays an important role in cell-extracellular matrix interactions, cell-cell interactions, and subsequent intracellular responses. In addition, we review recent studies on the mechanobiology of hPSCs, in which engineered micromechanical environments were used to investigate effects of specific physical cues. Identifying key physical cues and understanding their mechanism will ultimately help in harnessing the full potential of hPSCs for clinical applications.
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Affiliation(s)
- Daniel Nampe
- 1Department of Bioengineering, University of California, Riverside, CA, USA
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26
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Kim DH, Wirtz D. Predicting how cells spread and migrate: focal adhesion size does matter. Cell Adh Migr 2013; 7:293-6. [PMID: 23628962 DOI: 10.4161/cam.24804] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Efficient cell migration is central to the normal development of tissues and organs and is involved in a wide range of human diseases, including cancer metastasis, immune responses, and cardiovascular disorders. Mesenchymal migration is modulated by focal-adhesion proteins, which organize into large integrin-rich protein complexes at the basal surface of adherent cells. Whether the extent of clustering of focal-adhesion proteins is actually required for effective migration is unclear. We recently demonstrated that the depletion of major focal-adhesion proteins, as well as modulation of matrix compliance, actin assembly, mitochondrial activity, and DNA recombination, all converged into highly predictable, inter-related, biphasic changes in focal adhesion size and cell migration. Herein, we further discuss the role of focal adhesions in controlling cell spreading and test their potential role in cell migration.
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Affiliation(s)
- Dong-Hwee Kim
- Johns Hopkins Physical Sciences - Oncology Center, The Johns Hopkins University, Baltimore, MD, USA
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27
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Wei Q, Reidler D, Shen MY, Huang H. Keratinocyte cytoskeletal roles in cell sheet engineering. BMC Biotechnol 2013; 13:17. [PMID: 23442760 PMCID: PMC3599259 DOI: 10.1186/1472-6750-13-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Accepted: 02/22/2013] [Indexed: 01/27/2023] Open
Abstract
Background There is an increasing need to understand cell-cell interactions for cell and tissue engineering purposes, such as optimizing cell sheet constructs, as well as for examining adhesion defect diseases. For cell-sheet engineering, one major obstacle to sheet function is that cell sheets in suspension are fragile and, over time, will contract. While the role of the cytoskeleton in maintaining the structure and adhesion of cells cultured on a rigid substrate is well-characterized, a systematic examination of the role played by different components of the cytoskeleton in regulating cell sheet contraction and cohesion in the absence of a substrate has been lacking. Results In this study, keratinocytes were cultured until confluent and cell sheets were generated using dispase to remove the influence of the substrate. The effects of disrupting actin, microtubules or intermediate filaments on cell-cell interactions were assessed by measuring cell sheet cohesion and contraction. Keratin intermediate filament disruption caused comparable effects on cell sheet cohesion and contraction, when compared to actin or microtubule disruption. Interfering with actomyosin contraction demonstrated that interfering with cell contraction can also diminish cell cohesion. Conclusions All components of the cytoskeleton are involved in maintaining cell sheet cohesion and contraction, although not to the same extent. These findings demonstrate that substrate-free cell sheet biomechanical properties are dependent on the integrity of the cytoskeleton network.
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Affiliation(s)
- Qi Wei
- Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace, 500 W 120th Street, MC 8904, New York, NY 10027, USA
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Abstract
Focal adhesions are large protein complexes organized at the basal surface of cells, which physically connect the extracellular matrix to the cytoskeleton and have long been speculated to mediate cell migration. However, whether clustering of these molecular components into focal adhesions is actually required for these proteins to regulate cell motility is unclear. Here we use quantitative microscopy to characterize descriptors of focal adhesion and cell motility for mouse embryonic fibroblasts and human fibrosarcoma cells, across a wide range of matrix compliance and following genetic manipulations of focal adhesion proteins (vinculin, talin, zyxin, FAK, and paxilin). This analysis reveals a tight, biphasic gaussian relationship between mean size of focal adhesions (not their number, surface density, or shape) and cell speed. The predictive power of this relationship is comprehensively validated by disrupting nonfocal adhesion proteins (α-actinin, F-actin, and myosin II) and subcellular organelles (mitochondria, nuclear DNA, etc.) not known to affect either focal adhesions or cell migration. This study suggests that the mean size of focal adhesions robustly and precisely predicts cell speed independently of focal adhesion surface density and molecular composition.
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Affiliation(s)
- Dong-Hwee Kim
- Johns Hopkins Physical Sciences-Oncology Center and Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
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29
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Shen MY, Michaelson J, Huang H. Rheological responses of cardiac fibroblasts to mechanical stretch. Biochem Biophys Res Commun 2012; 430:1028-33. [PMID: 23261449 DOI: 10.1016/j.bbrc.2012.12.044] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Accepted: 12/10/2012] [Indexed: 10/27/2022]
Abstract
Rheological characterization of cells using passive particle tracking techniques can yield substantial information regarding local cellular material properties. However, limited work has been done to establish the changes in material properties of mechanically-responsive cells that experience external stimuli. In this study, cardiac fibroblasts plated on either fibronectin or collagen were treated with cytochalasin, mechanically stretched, or both, and their trajectories and complex moduli were extracted. Results demonstrate that both solid and fluid components were altered by such treatments in a receptor-dependent manner, and that, interestingly, cells treated with cytochalasin were still capable of stiffening in response to mechanical stimuli despite gross stress fiber disruption. These results suggest that the material properties of cells are dependent on a variety of environmental cues and can provide insight into physiological and disease processes.
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Affiliation(s)
- Min Ye Shen
- Columbia University, New York, NY 10027, USA
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30
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Functions of nonmuscle myosin II in assembly of the cellular contractile system. PLoS One 2012; 7:e40814. [PMID: 22808267 PMCID: PMC3396643 DOI: 10.1371/journal.pone.0040814] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Accepted: 06/17/2012] [Indexed: 01/13/2023] Open
Abstract
The contractile system of nonmuscle cells consists of interconnected actomyosin networks and bundles anchored to focal adhesions. The initiation of the contractile system assembly is poorly understood structurally and mechanistically, whereas system's maturation heavily depends on nonmuscle myosin II (NMII). Using platinum replica electron microscopy in combination with fluorescence microscopy, we characterized the structural mechanisms of the contractile system assembly and roles of NMII at early stages of this process. We show that inhibition of NMII by a specific inhibitor, blebbistatin, in addition to known effects, such as disassembly of stress fibers and mature focal adhesions, also causes transformation of lamellipodia into unattached ruffles, loss of immature focal complexes, loss of cytoskeleton-associated NMII filaments and peripheral accumulation of activated, but unpolymerized NMII. After blebbistatin washout, assembly of the contractile system begins with quick and coordinated recovery of lamellipodia and focal complexes that occurs before reappearance of NMII bipolar filaments. The initial formation of focal complexes and subsequent assembly of NMII filaments preferentially occurred in association with filopodial bundles and concave actin bundles formed by filopodial roots at the lamellipodial base. Over time, accumulating NMII filaments help to transform the precursor structures, focal complexes and associated thin bundles, into stress fibers and mature focal adhesions. However, semi-sarcomeric organization of stress fibers develops at much slower rate. Together, our data suggest that activation of NMII motor activity by light chain phosphorylation occurs at the cell edge and is uncoupled from NMII assembly into bipolar filaments. We propose that activated, but unpolymerized NMII initiates focal complexes, thus providing traction for lamellipodial protrusion. Subsequently, the mechanical resistance of focal complexes activates a load-dependent mechanism of NMII polymerization in association with attached bundles, leading to assembly of stress fibers and maturation of focal adhesions.
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31
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Bertseva E, Grebenkov D, Schmidhauser P, Gribkova S, Jeney S, Forró L. Optical trapping microrheology in cultured human cells. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2012; 35:63. [PMID: 22821510 DOI: 10.1140/epje/i2012-12063-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Revised: 11/08/2011] [Accepted: 06/20/2012] [Indexed: 05/26/2023]
Abstract
We present the microrheological study of the two close human epithelial cell lines: non-cancerous HCV29 and cancerous T24. The optical tweezers tracking was applied to extract the several seconds long trajectories of endogenous lipid granules at time step of 1μs. They were analyzed using a recently proposed equation for mean square displacement (MSD) in the case of subdiffusion influenced by an optical trap. This equation leads to an explicit form for viscoelastic moduli. The moduli of the two cell lines were found to be the same within the experimental accuracy for frequencies 10(2) - 10(5) Hz. For both cell lines subdiffusion was observed with the exponent close to 3/4, the value predicted by the theory of semiflexible polymers. For times longer than 0.1s the MSD of cancerous cells exceeds the MSD of non-cancerous cells for all values of the trapping force. Such behavior can be interpreted as a signature of the active processes and prevents the extraction of the low-frequency viscoelastic moduli for the living cells by passive microrheology.
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Affiliation(s)
- E Bertseva
- Laboratory of Physics of Complex Matter, Ecole polytechnique federale de Lausanne (EPFL), Lausanne VD, Switzerland.
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32
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Vitolo MI, Boggs AE, Whipple RA, Yoon JR, Thompson K, Matrone MA, Cho EH, Balzer EM, Martin SS. Loss of PTEN induces microtentacles through PI3K-independent activation of cofilin. Oncogene 2012; 32:2200-10. [PMID: 22689060 DOI: 10.1038/onc.2012.234] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Loss of PTEN tumor suppressor enhances metastatic risk in breast cancer, although the underlying mechanisms are poorly defined. We report that homozygous deletion of PTEN in mammary epithelial cells induces tubulin-based microtentacles (McTNs) that facilitate cell reattachment and homotypic aggregation. Treatment with contractility-modulating drugs showed that McTNs in PTEN(-/-) cells are suppressible by controlling the actin cytoskeleton. Because outward microtubule extension is counteracted by actin cortical contraction, increased activity of actin-severing proteins could release constraints on McTN formation in PTEN(-/-) cells. One such actin-severing protein, cofilin, is activated in detached PTEN(-/-) cells that could weaken the actin cortex to promote McTNs. Expression of wild-type cofilin, an activated mutant (S3A), and an inactive mutant (S3E) demonstrated that altering cofilin phosphorylation directly affects McTNs formation. Chemical inhibition of PI3K did not reduce McTNs or inactivate cofilin in PTEN(-/-) cells. Additionally, knock-in expression of the two most common PI3K-activating mutations observed in human cancer patients did not increase McTNs or activate cofilin. PTEN loss and PI3K activation also caused differential activation of the cofilin regulators, LIM-kinase1 (LIMK) and Slingshot-1L (SSH). Furthermore, McTNs were suppressed and cofilin was inactivated by restoration of PTEN in the PTEN(-/-) cells, indicating that both the elevation of McTNs and the activation of cofilin are specific results arising from PTEN loss. These data identify a novel mechanism by which PTEN loss could remodel the cortical actin network to facilitate McTNs that promote tumor cell reattachment and aggregation. Using isogenic MCF-10A PTEN(-/-) and PIK3CA mutants, we have further demonstrated that there are clear differences in activation of cofilin, LIMK and SSH between PTEN loss and PI3K activation, providing a new evidence that these mutations yield distinct cytoskeletal phenotypes, which could have an impact on tumor biology.
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Affiliation(s)
- M I Vitolo
- University of Maryland Marlene and Stewart Greenebaum NCI Cancer Center, Baltimore, MD 21201, USA
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33
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Abstract
High-throughput ballistic injection nanorheology is a method for the quantitative study of cell mechanics. Cell mechanics are measured by ballistic injection of submicron particles into the cytoplasm of living cells and tracking the spontaneous displacement of the particles at high spatial resolution. The trajectories of the cytoplasm-embedded particles are transformed into mean-squared displacements, which are subsequently transformed into frequency-dependent viscoelastic moduli and time-dependent creep compliance of the cytoplasm. This method allows for the study of a wide range of cellular conditions, including cells inside a 3D matrix, cell subjected to shear flows and biochemical stimuli, and cells in a live animal. Ballistic injection lasts <1 min and is followed by overnight incubation. Multiple particle tracking for one cell lasts <1 min. Forty cells can be examined in <1 h.
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Robert D, Aubertin K, Bacri JC, Wilhelm C. Magnetic nanomanipulations inside living cells compared with passive tracking of nanoprobes to get consensus for intracellular mechanics. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 85:011905. [PMID: 22400589 DOI: 10.1103/physreve.85.011905] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Indexed: 05/31/2023]
Abstract
During the last decade, the development of nanomaterials to penetrate inside living cells has been the focus of a large number of studies, with applications for the biomedical field. However, the further dynamics of these nanomaterials inside the cells is dictated by the intracellular environment and in particular its mechanical properties. The mechanical characteristics of the cell interior can be probed with either active or passive microrheological approaches. However, active intracellular microrheology is still in its infancy, owing to the difficulty of inserting probes that can be manipulated by external forces. Here we review recent active microrheology studies using magnetic nanoprobes inserted into endosomes or phagosomes as useful approaches for measuring frequency-dependent viscoelasticity, for mapping the viscoelastic landscape, as well as for identifying the contribution of individual cytoskeleton components and the influence of cell motility. The results of such direct measurements challenge the validity of more typical passive approaches in which the spontaneous displacement of embedded nanoprobes is measured. Here we discuss that one must distinguish probes suitable for use in conditions of thermal equilibrium, whose movements reflect the mechanical environment from probes that interact actively with the cytoplasm and cytoskeleton, in a state of nonequilibrium for which fluctuation-dissipation theorem no longer holds. However, when data on these probes' viscoelastic microenvironment is available, such passive probe movements can yield useful information on the forces responsible for intracellular activity.
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Affiliation(s)
- Damien Robert
- Laboratoire Matière et Systèmes Complexes, CNRS UMR 7057, Université Paris 7, 75013 Paris, France
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35
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Hale CM, Chen WC, Khatau SB, Daniels BR, Lee JSH, Wirtz D. SMRT analysis of MTOC and nuclear positioning reveals the role of EB1 and LIC1 in single-cell polarization. J Cell Sci 2011; 124:4267-85. [PMID: 22193958 DOI: 10.1242/jcs.091231] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In several migratory cells, the microtubule-organizing center (MTOC) is repositioned between the leading edge and nucleus, creating a polarized morphology. Although our understanding of polarization has progressed as a result of various scratch-wound and cell migration studies, variations in culture conditions required for such assays have prevented a unified understanding of the intricacies of MTOC and nucleus positioning that result in cell polarization. Here, we employ a new SMRT (for sparse, monolayer, round, triangular) analysis that uses a universal coordinate system based on cell centroid to examine the pathways regulating MTOC and nuclear positions in cells plated in a variety of conditions. We find that MTOC and nucleus positioning are crucially and independently affected by cell shape and confluence; MTOC off-centering correlates with the polarization of single cells; acto-myosin contractility and microtubule dynamics are required for single-cell polarization; and end binding protein 1 and light intermediate chain 1, but not Par3 and light intermediate chain 2, are required for single-cell polarization and directional cell motility. Using various cellular geometries and conditions, we implement a systematic and reproducible approach to identify regulators of MTOC and nucleus positioning that depend on extracellular guidance cues.
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Affiliation(s)
- Christopher M Hale
- Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218, USA
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36
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Direct detection of cellular adaptation to local cyclic stretching at the single cell level by atomic force microscopy. Biophys J 2011; 100:564-572. [PMID: 21281570 DOI: 10.1016/j.bpj.2010.12.3693] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2010] [Revised: 10/29/2010] [Accepted: 12/02/2010] [Indexed: 01/13/2023] Open
Abstract
The cellular response to external mechanical forces has important effects on numerous biological phenomena. The sequences of molecular events that underlie the observed changes in cellular properties have yet to be elucidated in detail. Here we have detected the responses of a cultured cell against locally applied cyclic stretching and compressive forces, after creating an artificial focal adhesion under a glass bead attached to the cantilever of an atomic force microscope. The cell tension initially increased in response to the tensile stress and then decreased within ∼1 min as a result of viscoelastic properties of the cell. This relaxation was followed by a gradual increase in tension extending over several minutes. The slow recovery of tension ceased after several cycles of force application. This tension-recovering activity was inhibited when cells were treated with cytochalasin D, an inhibitor of actin polymerization, or with (-)-blebbistatin, an inhibitor of myosin II ATPase activity, suggesting that the activity was driven by actin-myosin interaction. To our knowledge, this is the first quantitative analysis of cellular mechanical properties during the process of adaptation to locally applied cyclic external force.
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Modulating malignant epithelial tumor cell adhesion, migration and mechanics with nanorod surfaces. Biomed Microdevices 2011; 13:89-95. [PMID: 20830527 DOI: 10.1007/s10544-010-9473-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The failure of tumor stents used for palliative therapy is due in part to the adhesion of tumor cells to the stent surface. It is therefore desirable to develop approaches to weaken the adhesion of malignant tumor cells to surfaces. We have previously developed SiO₂ coated nanorods that resist the adhesion of normal endothelial cells and fibroblasts. The adhesion mechanisms in malignant tumor cells are significantly altered from normal cells; therefore, it is unclear if nanorods can similarly resist tumor cell adhesion. In this study, we show that the morphology of tumor epithelial cells cultured on nanorods is rounded compared to flat surfaces and associated with decreased cellular stiffness and non-muscle myosin II phosphorylation. Tumor cell viability and proliferation was unchanged on nanorods. Adherent cell numbers were significantly decreased while single tumor cell motility was increased on nanorods compared to flat surfaces. Together, these results suggest that nanorods can be used to weaken malignant tumor cell adhesion, and therefore potentially improve tumor stent performance.
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38
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Daniels BR, Hale CM, Khatau SB, Kusuma S, Dobrowsky TM, Gerecht S, Wirtz D. Differences in the microrheology of human embryonic stem cells and human induced pluripotent stem cells. Biophys J 2011; 99:3563-70. [PMID: 21112280 DOI: 10.1016/j.bpj.2010.10.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Revised: 10/05/2010] [Accepted: 10/07/2010] [Indexed: 01/24/2023] Open
Abstract
Embryonic and adult fibroblasts can be returned to pluripotency by the expression of reprogramming genes. Multiple lines of evidence suggest that these human induced pluripotent stem (hiPS) cells and human embryonic stem (hES) cells are behaviorally, karyotypically, and morphologically similar. Here we sought to determine whether the physical properties of hiPS cells, including their micromechanical properties, are different from those of hES cells. To this end, we use the method of particle tracking microrheology to compare the viscoelastic properties of the cytoplasm of hES cells, hiPS cells, and the terminally differentiated parental human fibroblasts from which our hiPS cells are derived. Our results indicate that although the cytoplasm of parental fibroblasts is both viscous and elastic, the cytoplasm of hiPS cells does not exhibit any measurable elasticity and is purely viscous over a wide range of timescales. The viscous phenotype of hiPS cells is recapitulated in parental cells with disassembled actin filament network. The cytoplasm of hES cells is predominantly viscous but contains subcellular regions that are also elastic. This study supports the hypothesis that intracellular elasticity correlates with the degree of cellular differentiation and reveals significant differences in the mechanical properties of hiPS cells and hES cells. Because mechanical stimuli have been shown to mediate the precise fate of differentiating stem cells, our results support the concept that stem cell "softness" is a key feature of force-mediated differentiation of stem cells and suggest there may be subtle functional differences between force-mediated differentiation of hiPS cells and hES cells.
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Affiliation(s)
- Brian R Daniels
- Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, Baltimore, Maryland, USA
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39
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Abstract
When tissue cells are plated on a flexible substrate, durotaxis, the directed migration of cells toward mechanically stiff regions, has been observed. Environmental mechanical signals are not only important in cell migration but also seem to influence all aspects of cell differentiation and development, including the metastatic process in cancer cells. Based on a theoretical model suggesting that this mechanosensation has a mechanical basis, we introduce a simple model of a cell by considering the contraction of F-actin bundles containing myosin motors (stress fibers) mediated by the movement of adhesions. We show that, when presented with a linear stiffness gradient, this simple model exhibits durotaxis. Interestingly, since stress fibers do not form on soft surfaces and since adhesion sliding occurs very slowly on hard surfaces, the model predicts that the expected cell velocity reaches a maximum at an intermediate stiffness. This prediction can be experimentally tested. We therefore argue that stiffness-dependent cellular adaptations (mechanosensation) and durotaxis are intimately related and may share a mechanical basis. We therefore identify the essential physical ingredients, which combined with additional biochemical mechanisms can explain durotaxis and mechanosensation in cells.
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Affiliation(s)
- Ben Harland
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
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Contractility dominates adhesive ligand density in regulating cellular de-adhesion and retraction kinetics. Ann Biomed Eng 2010; 39:1163-73. [PMID: 21046466 PMCID: PMC3069333 DOI: 10.1007/s10439-010-0195-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Accepted: 10/17/2010] [Indexed: 01/09/2023]
Abstract
Cells that are enzymatically detached from a solid substrate rapidly round up as the tensile prestress in the cytoskeleton is suddenly unopposed by cell-ECM adhesions. We recently showed that this retraction follows sigmoidal kinetics with time constants that correlate closely with cortical stiffness values. This raises the promising prospect that these de-adhesion measurements may be used for high-throughput screening of cell mechanical properties; however, an important limitation to doing so is the possibility that the retraction kinetics may also be influenced and potentially rate-limited by the time needed to sever matrix adhesions. In this study, we address this open question by separating contributions of contractility and adhesion to cellular de-adhesion and retraction kinetics. We first develop serum-free conditions under which U373 MG glioma cells can be cultured on substrates of fixed fibronectin density without direct matrix contributions from the medium. We show that while spreading area increases with ECM protein density, cortical stiffness and the time constants of retraction do not. Conversely, addition of lysophosphatidic acid (LPA) to stimulate cell contractility strongly speeds retraction, independent of the initial matrix protein density and LPA's contributions to spreading area. All of these trends hold in serum-rich medium commonly used in tissue culture, with the time constants of retraction much more closely tracking cortical stiffness than adhesive ligand density or cell spreading. These results support the use of cellular de-adhesion measurements to track cellular mechanical properties.
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Abstract
Cells use actin bundles infused with myosin to exert contractile forces on the extracellular environment. This active tension is essential for cellular mechanosensation. Now, the role of actin crosslinkers in stabilizing and repairing the actin bundles is coming into clearer view.
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Affiliation(s)
- Sean X Sun
- Johns Hopkins University, Department of Mechanical Engineering, Institute for NanoBioTechnology, and Physical Science for Oncology Center, Baltimore, MD 21218, USA.
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In vivo determination of fluctuating forces during endosome trafficking using a combination of active and passive microrheology. PLoS One 2010; 5:e10046. [PMID: 20386607 PMCID: PMC2850365 DOI: 10.1371/journal.pone.0010046] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2009] [Accepted: 03/07/2010] [Indexed: 11/19/2022] Open
Abstract
Background Regulation of intracellular trafficking is a central issue in cell biology. The forces acting on intracellular vesicles (endosomes) can be assessed in living cells by using a combination of active and passive microrheology. Methodology/Principal Findings This dual approach is based on endosome labeling with magnetic nanoparticles. The resulting magnetic endosomes act both as probes that can be manipulated with external magnetic fields to infer the viscoelastic modulus of their surrounding microenvironment, and as biological vehicles that are trafficked along the microtubule network by means of forces generated by molecular motors. The intracellular viscoelastic modulus exhibits power law dependence with frequency, which is microtubule and actin-dependent. The mean square displacements of endosomes do not follow the predictions of the fluctuation-dissipation theorem, which offers evidence for active force generation. Microtubule disruption brings the intracellular medium closer to thermal equilibrium: active forces acting on the endosomes depend on microtubule-associated motors. The power spectra of these active forces, deduced through the use of a generalized Langevin equation, show a power law decrease with frequency and reveal an actin-dependent persistence of the force with time. Experimental spectra have been reproduced by a simple model consisting in a series of force steps power-law distributed in time. This model enlightens the role of the cytoskeleton dependent force exerted on endosomes to perform intracellular trafficking. Conclusions/Significance In this work, the influence of cytoskeleton components and molecular motors on intracellular viscoelasticity and transport is addressed. The use of an original probe, the magnetic endosome, allows retrieving the power spectrum of active forces on these organelles thanks to interrelated active and passive measures. Finally a computational model gives estimates of the force itself and hence of the number of the motors pulling on endosomes.
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