1
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Shivers JL, MacKintosh FC. Nonlinear Poisson effect in affine semiflexible polymer networks. Phys Rev E 2024; 110:014502. [PMID: 39160898 DOI: 10.1103/physreve.110.014502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2024] [Accepted: 06/28/2024] [Indexed: 08/21/2024]
Abstract
Stretching an elastic material along one axis typically induces contraction along the transverse axes, a phenomenon known as the Poisson effect. From these strains, one can compute the specific volume, which generally either increases or, in the incompressible limit, remains constant as the material is stretched. However, in networks of semiflexible or stiff polymers, which are typically highly compressible yet stiffen significantly when stretched, one instead sees a significant reduction in specific volume under finite strains. This volume reduction is accompanied by increasing alignment of filaments along the strain axis and a nonlinear elastic response, with stiffening of the apparent Young's modulus. For semiflexible networks, in which entropic bending elasticity governs the linear elastic regime, the nonlinear Poisson effect is caused by the nonlinear force-extension relationship of the constituent filaments, which produces a highly asymmetric response of the constituent polymers to stretching and compression. The details of this relationship depend on the geometric and elastic properties of the underlying filaments, which can vary greatly in experimental systems. Here, we provide a comprehensive characterization of the nonlinear Poisson effect in an affine network model and explore the influence of filament properties on essential features of both microscopic and macroscopic response, including strain-driven alignment and volume reduction.
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Affiliation(s)
- Jordan L Shivers
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, USA
- Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, USA
- James Franck Institute, University of Chicago, Chicago, Illinois 60637, USA
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, USA
| | - Fred C MacKintosh
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, USA
- Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, USA
- Department of Chemistry, Rice University, Houston, Texas 77005, USA
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
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2
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Ueda Y, Matsunaga D, Deguchi S. Asymmetric response emerges between creation and disintegration of force-bearing subcellular structures as revealed by percolation analysis. Integr Biol (Camb) 2024; 16:zyae012. [PMID: 38900169 DOI: 10.1093/intbio/zyae012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2024] [Revised: 05/23/2024] [Indexed: 06/21/2024]
Abstract
Cells dynamically remodel their internal structures by modulating the arrangement of actin filaments (AFs). In this process, individual AFs exhibit stochastic behavior without knowing the macroscopic higher-order structures they are meant to create or disintegrate, but the mechanism allowing for such stochastic process-driven remodeling of subcellular structures remains incompletely understood. Here we employ percolation theory to explore how AFs interacting only with neighboring ones without recognizing the overall configuration can nonetheless create a substantial structure referred to as stress fibers (SFs) at particular locations. We determined the interaction probabilities of AFs undergoing cellular tensional homeostasis, a fundamental property maintaining intracellular tension. We showed that the duration required for the creation of SFs is shortened by the increased amount of preexisting actin meshwork, while the disintegration occurs independently of the presence of actin meshwork, suggesting that the coexistence of tension-bearing and non-bearing elements allows cells to promptly transition to new states in accordance with transient environmental changes. The origin of this asymmetry between creation and disintegration, consistently observed in actual cells, is elucidated through a minimal model analysis by examining the intrinsic nature of mechano-signal transmission. Specifically, unlike the symmetric case involving biochemical communication, physical communication to sense environmental changes is facilitated via AFs under tension, while other free AFs dissociated from tension-bearing structures exhibit stochastic behavior. Thus, both the numerical and minimal models demonstrate the essence of intracellular percolation, in which macroscopic asymmetry observed at the cellular level emerges not from microscopic asymmetry in the interaction probabilities of individual molecules, but rather only as a consequence of the manner of the mechano-signal transmission. These results provide novel insights into the role of the mutual interplay between distinct subcellular structures with and without tension-bearing capability. Insight: Cells continuously remodel their internal elements or structural proteins in response to environmental changes. Despite the stochastic behavior of individual structural proteins, which lack awareness of the larger subcellular structures they are meant to create or disintegrate, this self-assembly process somehow occurs to enable adaptation to the environment. Here we demonstrated through percolation simulations and minimal model analyses that there is an asymmetry in the response between the creation and disintegration of subcellular structures, which can aid environmental adaptation. This asymmetry inherently arises from the nature of mechano-signal transmission through structural proteins, namely tension-mediated information exchange within cells, despite the stochastic behavior of individual proteins lacking asymmetric characters in themselves.
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Affiliation(s)
- Yuika Ueda
- Division of Bioengineering, Graduate School of Engineering Science, Osaka University
| | - Daiki Matsunaga
- Division of Bioengineering, Graduate School of Engineering Science, Osaka University
| | - Shinji Deguchi
- Division of Bioengineering, Graduate School of Engineering Science, Osaka University
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3
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Amiri S, Muresan C, Shang X, Huet-Calderwood C, Schwartz MA, Calderwood DA, Murrell M. Intracellular tension sensor reveals mechanical anisotropy of the actin cytoskeleton. Nat Commun 2023; 14:8011. [PMID: 38049429 PMCID: PMC10695988 DOI: 10.1038/s41467-023-43612-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 11/15/2023] [Indexed: 12/06/2023] Open
Abstract
The filamentous actin (F-actin) cytoskeleton is a composite material consisting of cortical actin and bundled F-actin stress fibers, which together mediate the mechanical behaviors of the cell, from cell division to cell migration. However, as mechanical forces are typically measured upon transmission to the extracellular matrix, the internal distribution of forces within the cytoskeleton is unknown. Likewise, how distinct F-actin architectures contribute to the generation and transmission of mechanical forces is unclear. Therefore, we have developed a molecular tension sensor that embeds into the F-actin cytoskeleton. Using this sensor, we measure tension within stress fibers and cortical actin, as the cell is subject to uniaxial stretch. We find that the mechanical response, as measured by FRET, depends on the direction of applied stretch relative to the cell's axis of alignment. When the cell is aligned parallel to the direction of the stretch, stress fibers and cortical actin both accumulate tension. By contrast, when aligned perpendicular to the direction of stretch, stress fibers relax tension while the cortex accumulates tension, indicating mechanical anisotropy within the cytoskeleton. We further show that myosin inhibition regulates this anisotropy. Thus, the mechanical anisotropy of the cell and the coordination between distinct F-actin architectures vary and depend upon applied load.
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Affiliation(s)
- Sorosh Amiri
- Systems Biology Institute, 850 West Campus Drive, Yale University, West Haven, CT, 06516, USA
- Department of Mechanical Engineering and Material Science, 17 Hillhouse Ave, Yale University, New Haven, CT, 06511, USA
| | - Camelia Muresan
- Systems Biology Institute, 850 West Campus Drive, Yale University, West Haven, CT, 06516, USA
- Department of Biomedical Engineering, 17 Hillhouse Ave, Yale University, New Haven, CT, 06511, USA
| | - Xingbo Shang
- Systems Biology Institute, 850 West Campus Drive, Yale University, West Haven, CT, 06516, USA
- Department of Biomedical Engineering, 17 Hillhouse Ave, Yale University, New Haven, CT, 06511, USA
| | | | - Martin A Schwartz
- Department of Biomedical Engineering, 17 Hillhouse Ave, Yale University, New Haven, CT, 06511, USA
- Department of Cell Biology, 333 Cedar St, Yale University, New Haven, CT, 06510, USA
- Yale Cardiovascular Research Center, 300 George St, New Haven, CT, 06511, USA
| | - David A Calderwood
- Department of Pharmacology, 333 Cedar St, Yale University, New Haven, CT, 06510, USA
- Department of Cell Biology, 333 Cedar St, Yale University, New Haven, CT, 06510, USA
| | - Michael Murrell
- Systems Biology Institute, 850 West Campus Drive, Yale University, West Haven, CT, 06516, USA.
- Department of Biomedical Engineering, 17 Hillhouse Ave, Yale University, New Haven, CT, 06511, USA.
- Department of Physics, 217 Prospect Street, Yale University, New Haven, CT, 06511, USA.
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4
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Giverso C, Loy N, Lucci G, Preziosi L. Cell orientation under stretch: A review of experimental findings and mathematical modelling. J Theor Biol 2023; 572:111564. [PMID: 37391125 DOI: 10.1016/j.jtbi.2023.111564] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Accepted: 06/15/2023] [Indexed: 07/02/2023]
Abstract
The key role of electro-chemical signals in cellular processes had been known for many years, but more recently the interplay with mechanics has been put in evidence and attracted substantial research interests. Indeed, the sensitivity of cells to mechanical stimuli coming from the microenvironment turns out to be relevant in many biological and physiological circumstances. In particular, experimental evidence demonstrated that cells on elastic planar substrates undergoing periodic stretches, mimicking native cyclic strains in the tissue where they reside, actively reorient their cytoskeletal stress fibres. At the end of the realignment process, the cell axis forms a certain angle with the main stretching direction. Due to the importance of a deeper understanding of mechanotransduction, such a phenomenon was studied both from the experimental and the mathematical modelling point of view. The aim of this review is to collect and discuss both the experimental results on cell reorientation and the fundamental features of the mathematical models that have been proposed in the literature.
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Affiliation(s)
- Chiara Giverso
- Department of Mathematical Sciences "G.L. Lagrange", Politecnico di Torino, Corso Duca degli Abruzzi 24, Turin, 10126, Italy.
| | - Nadia Loy
- Department of Mathematical Sciences "G.L. Lagrange", Politecnico di Torino, Corso Duca degli Abruzzi 24, Turin, 10126, Italy.
| | - Giulio Lucci
- Department of Mathematical Sciences "G.L. Lagrange", Politecnico di Torino, Corso Duca degli Abruzzi 24, Turin, 10126, Italy.
| | - Luigi Preziosi
- Department of Mathematical Sciences "G.L. Lagrange", Politecnico di Torino, Corso Duca degli Abruzzi 24, Turin, 10126, Italy.
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5
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Loy N, Preziosi L. A Statistical Mechanics Approach to Describe Cell Reorientation Under Stretch. Bull Math Biol 2023; 85:60. [PMID: 37249663 DOI: 10.1007/s11538-023-01161-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 04/25/2023] [Indexed: 05/31/2023]
Abstract
Experiments show that when a monolayer of cells cultured on an elastic substratum is subject to a cyclic stretch, cells tend to reorient either perpendicularly or at an oblique angle with respect to the main stretching direction. Due to stochastic effects, however, the distribution of angles achieved by the cells is broader and, experimentally, histograms over the interval [Formula: see text] are usually reported. Here we will determine the evolution and the stationary state of probability density functions describing the statistical distribution of the orientations of the cells using Fokker-Planck equations derived from microscopic rules for describing the reorientation process of the cell. As a first attempt, we shall use a stochastic differential equation related to a very general elastic energy that the cell tries to minimize and, we will show that the results of the time integration and of the stationary state of the related forward Fokker-Planck equation compare very well with experimental results obtained by different researchers. Then, in order to model more accurately the microscopic process of cell reorientation and to shed light on the mechanisms performed by cells that are subject to cyclic stretch, we consider discrete in time random processes that allow to recover Fokker-Planck equations through classical tools of kinetic theory. In particular, we shall introduce a model of reorientation as a function of the rotation angle as a result of an optimal control problem. Also in this latter case the results match very well with experiments.
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Affiliation(s)
- N Loy
- Politecnico di Torino, Torino, Italy.
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6
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Wen SM, Wen WC, Chao PHG. Zyxin and actin structure confer anisotropic YAP mechanotransduction. Acta Biomater 2022; 152:313-320. [PMID: 36089236 DOI: 10.1016/j.actbio.2022.08.079] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 08/24/2022] [Accepted: 08/31/2022] [Indexed: 11/01/2022]
Abstract
Tissues and the embedded cells experience anisotropic deformations due to their functions and anatomical locations. The resident cells, such as tenocytes and muscle cells, are often restricted by their extracellular matrix and organize parallel to their major loading direction, yet most studies on cellular responses to strains use isotropic substrates without predetermined organizations. To understand how confined cells sense and respond to anisotropic loading, we combine cell patterning and uniaxial stretch to have precise geometric control. Dynamic stretch parallel to the long axis of the cell activates YAP nuclear translocation, but not when stretched in the perpendicular direction. Looking at the initial cytoskeleton response, parallel stretch leads to actin breakage and repair within the first minute, mediated by zyxin, the focal adhesion protein. In addition, this zyxin-mediated repair response is controlled by focal adhesion kinase (FAK) and leads to YAP signaling. As these factors are intimately involved in a wide range of mechanical regulation, our findings point to new roles of zyxin and YAP in anisotropic mechanotransduction, and may provide additional perspectives in cellular adaptive responses and tissue homeostasis. STATEMENT OF SIGNIFICANCE: Structure and deformation of tissues control gene expression, migration, and proliferation of the resident cells. In an effort to understand the underlying mechanisms, we find that the transcription cofactor YAP respond to mechanical stretch in a direction-dependent manner. We demonstrate that parallel stretch induces actin cytoskeleton damage, focal adhesion kinase (FAK) activation, and zyxin relocation, which are involved in the anisotropic YAP signaling. Our findings provide additional perspectives in the interactions of tissue structure and cell mechanotransduction.
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Affiliation(s)
- Shin-Min Wen
- Department of Biomedical Engineering, School of Medicine and School of Engineering National Taiwan University
| | - Wen-Cih Wen
- Department of Biomedical Engineering, School of Medicine and School of Engineering National Taiwan University
| | - Pen-Hsiu Grace Chao
- Department of Biomedical Engineering, School of Medicine and School of Engineering National Taiwan University.
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7
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Microfabricated Stretching Devices for Studying the Effects of Tensile Stress on Cells and Tissues. BIOCHIP JOURNAL 2022. [DOI: 10.1007/s13206-022-00073-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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8
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Wang C, Qu K, Wang J, Qin R, Li B, Qiu J, Wang G. Biomechanical regulation of planar cell polarity in endothelial cells. Biochim Biophys Acta Mol Basis Dis 2022; 1868:166495. [PMID: 35850177 DOI: 10.1016/j.bbadis.2022.166495] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 07/09/2022] [Accepted: 07/11/2022] [Indexed: 01/03/2023]
Abstract
Cell polarity refers to the uneven distribution of certain cytoplasmic components in a cell with a spatial order. The planar cell polarity (PCP), the cell aligns perpendicular to the polar plane, in endothelial cells (ECs) has become a research hot spot. The planar polarity of ECs has a positive significance on the regulation of cardiovascular dysfunction, pathological angiogenesis, and ischemic stroke. The endothelial polarity is stimulated and regulated by biomechanical force. Mechanical stimuli promote endothelial polarization and make ECs produce PCP to maintain the normal physiological and biochemical functions. Here, we overview recent advances in understanding the interplay and mechanism between PCP and ECs function involved in mechanical forces, with a focus on PCP signaling pathways and organelles in regulating the polarity of ECs. And then showed the related diseases caused by ECs polarity dysfunction. This study provides new ideas and therapeutic targets for the treatment of endothelial PCP-related diseases.
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Affiliation(s)
- Caihong Wang
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing, China
| | - Kai Qu
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing, China
| | - Jing Wang
- Institute of Food and Nutrition Development, Ministry of Agriculture and Rural Affairs, Beijing, China
| | - Rui Qin
- College of Life Sciences, South-Central University for Nationalities, Wuhan, China
| | - Bingyi Li
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing, China
| | - Juhui Qiu
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing, China.
| | - Guixue Wang
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing, China.
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9
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Tsukamoto S, Chiam KH, Asakawa T, Sawasaki K, Takesue N, Sakamoto N. Compressive forces driven by lateral actin fibers are a key to the nuclear deformation under uniaxial cell-substrate stretching. Biochem Biophys Res Commun 2022; 597:37-43. [PMID: 35123264 DOI: 10.1016/j.bbrc.2022.01.107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 01/26/2022] [Indexed: 01/10/2023]
Abstract
Cells sense the direction of mechanical stimuli including substrate stretching and show morphological and functional responses. The nuclear deformation with respect to the direction of mechanical stimuli is thought of as a vital factor in mechanosensitive intracellular signaling and gene transcription, but the detailed relationship between the direction of stimuli and nuclear deformation behavior is not fully solved yet. Here, we assessed the role of actin cytoskeletons in nuclear deformation caused by cell substrate stretching with different directions. Cells on a PDMS stretching chamber were subjected to a step-strain and changes of long- and short-axes of nucleus before and after stretching were evaluated in terms of nuclear orientation against the direction of stretching. Nuclei oriented parallel to the stretching direction showed elongation and shrinkage in the long and short axes, respectively, and vice versa. However, calculation of the aspect ratio (ratio of long- and short-axes) changes revealed orientation-depend nuclear deformation: The nucleus oriented parallel to the stretching direction showed a greater aspect ratio change than it aligned in the perpendicular direction of the stretching. A decrease in actin cytoskeletal tension significantly changed the nuclear deformation only in the short axis direction, thereby abolishing the orientation-depend deformation of the nucleus. These results suggest that lateral compressive forces exerted by the actin cytoskeleton is a key factor of orientation-depend deformation in short axis of the nucleus under the cell-substrate stretching condition, and may be crucial for mechano-sensing and responses to the cell-substrate stretching direction.
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Affiliation(s)
- Shingo Tsukamoto
- Department of Mechanical Systems Engineering, Tokyo Metropolitan University, Hachioji, Tokyo, Japan; Bioinformatics Institute, A∗STAR, Singapore.
| | | | - Takumi Asakawa
- Department of Mechanical Systems Engineering, Tokyo Metropolitan University, Hachioji, Tokyo, Japan
| | - Kaoru Sawasaki
- Department of Mechanical Systems Engineering, Tokyo Metropolitan University, Hachioji, Tokyo, Japan
| | - Naoyuki Takesue
- Department of Mechanical Systems Engineering, Tokyo Metropolitan University, Hachioji, Tokyo, Japan
| | - Naoya Sakamoto
- Department of Mechanical Systems Engineering, Tokyo Metropolitan University, Hachioji, Tokyo, Japan.
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10
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Xu J, Xu X, Li X, He S, Li D, Ji B. Cellular mechanics of wound formation in single cell layer under cyclic stretching. Biophys J 2022; 121:288-299. [PMID: 34902328 PMCID: PMC8790211 DOI: 10.1016/j.bpj.2021.12.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 11/16/2021] [Accepted: 12/09/2021] [Indexed: 01/21/2023] Open
Abstract
Wounds can be produced when cells and tissues are subjected to excessive forces, for instance, under pathological conditions or nonphysiological loading. However, the cellular behaviors in the wound formation process are not clear. Here we tested the behaviors of wound formation in the epithelial layer with an in-suit uniaxial stretching device. We found that the wound often nucleates at the position where the cells are dividing. The polarization direction of cells near the wound is preferentially along the wound edge, whereas the cells far from the wound are preferentially perpendicular to the stretching direction. The larger the wound area is, the higher is the aspect ratio of the cells around the wound. Increasing the cell density will strengthen the cell layer. The higher the cell density is, the smaller is the area of the wounds, and the weaker is the effect of stretching on the polarization of the cells. Furthermore, we built a coarse-grained cell model that can explicitly consider the elasticity and viscoelasticity of cells, cell-cell interaction, and cell active stress, by which we simulated the wound formation process and quantitatively analyzed the force and stress fields in the cell layer, particularly around the wound. These analyses reveal the cellular mechanisms of wound formation behaviors in the cell layer under stretching and shed useful light on tissue engineering and regenerative medicine for biomedical applications.
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Affiliation(s)
- Jiayi Xu
- Department of Applied Mechanics, Beijing Institute of Technology, Beijing, China,Oujiang Laboratory, Zhejiang, Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, China,Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, China
| | - Xiangyu Xu
- Department of Applied Mechanics, Beijing Institute of Technology, Beijing, China,Oujiang Laboratory, Zhejiang, Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, China
| | - Xiaojun Li
- Department of Applied Mechanics, Beijing Institute of Technology, Beijing, China
| | - Shijie He
- Center for Engineering in Medicine and Surgery, Department of Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Dechang Li
- Department of Engineering Mechanics, Zhejiang University, Hangzhou, China,Corresponding author
| | - Baohua Ji
- Oujiang Laboratory, Zhejiang, Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, China,Department of Engineering Mechanics, Zhejiang University, Hangzhou, China,Corresponding author
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11
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Abraham JA, Blaschke S, Tarazi S, Dreissen G, Vay SU, Schroeter M, Fink GR, Merkel R, Rueger MA, Hoffmann B. NSCs Under Strain-Unraveling the Mechanoprotective Role of Differentiating Astrocytes in a Cyclically Stretched Coculture With Differentiating Neurons. Front Cell Neurosci 2021; 15:706585. [PMID: 34630042 PMCID: PMC8497758 DOI: 10.3389/fncel.2021.706585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 08/31/2021] [Indexed: 11/19/2022] Open
Abstract
The neural stem cell (NSC) niche is a highly vascularized microenvironment that supplies stem cells with relevant biological and chemical cues. However, the NSCs’ proximity to the vasculature also means that the NSCs are subjected to permanent tissue deformation effected by the vessels’ heartbeat-induced pulsatile movements. Cultivating NSCs under common culture conditions neglects the—yet unknown—influence of this cyclic mechanical strain on neural stem cells. Under the hypothesis that pulsatile strain should affect essential NSC functions, a cyclic uniaxial strain was applied under biomimetic conditions using an in-house developed stretching system based on cross-linked polydimethylsiloxane (PDMS) elastomer. While lineage commitment remained unaffected by cyclic deformation, strain affected NSC quiescence and cytoskeletal organization. Unexpectedly, cyclically stretched stem cells aligned in stretch direction, a phenomenon unknown for other types of cells in the mammalian organism. The same effect was observed for young astrocytes differentiating from NSCs. In contrast, young neurons differentiating from NSCs did not show mechanoresponsiveness. The exceptional orientation of NSCs and young astrocytes in the stretch direction was blocked upon RhoA activation and went along with a lack of stress fibers. Compared to postnatal astrocytes and mature neurons, NSCs and their young progeny displayed characteristic and distinct mechanoresponsiveness. Data suggest a protective role of young astrocytes in mixed cultures of differentiating neurons and astrocytes by mitigating the mechanical stress of pulsatile strain on developing neurons.
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Affiliation(s)
- Jella-Andrea Abraham
- Mechanobiology, Institute of Biological Information Processing (IBI-2), Research Centre Juelich, Juelich, Germany
| | - Stefan Blaschke
- Department of Neurology, Faculty of Medicine and University Hospital, University of Cologne, Cologne, Germany.,Cognitive Neuroscience, Institute of Neuroscience and Medicine (INM-3), Research Centre Juelich, Juelich, Germany
| | - Samar Tarazi
- Mechanobiology, Institute of Biological Information Processing (IBI-2), Research Centre Juelich, Juelich, Germany
| | - Georg Dreissen
- Mechanobiology, Institute of Biological Information Processing (IBI-2), Research Centre Juelich, Juelich, Germany
| | - Sabine U Vay
- Department of Neurology, Faculty of Medicine and University Hospital, University of Cologne, Cologne, Germany
| | - Michael Schroeter
- Department of Neurology, Faculty of Medicine and University Hospital, University of Cologne, Cologne, Germany.,Cognitive Neuroscience, Institute of Neuroscience and Medicine (INM-3), Research Centre Juelich, Juelich, Germany
| | - Gereon R Fink
- Department of Neurology, Faculty of Medicine and University Hospital, University of Cologne, Cologne, Germany.,Cognitive Neuroscience, Institute of Neuroscience and Medicine (INM-3), Research Centre Juelich, Juelich, Germany
| | - Rudolf Merkel
- Mechanobiology, Institute of Biological Information Processing (IBI-2), Research Centre Juelich, Juelich, Germany
| | - Maria A Rueger
- Department of Neurology, Faculty of Medicine and University Hospital, University of Cologne, Cologne, Germany.,Cognitive Neuroscience, Institute of Neuroscience and Medicine (INM-3), Research Centre Juelich, Juelich, Germany
| | - Bernd Hoffmann
- Mechanobiology, Institute of Biological Information Processing (IBI-2), Research Centre Juelich, Juelich, Germany
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12
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Zhang D, Zhang R, Song X, Yan KC, Liang H. Uniaxial Cyclic Stretching Promotes Chromatin Accessibility of Gene Loci Associated With Mesenchymal Stem Cells Morphogenesis and Osteogenesis. Front Cell Dev Biol 2021; 9:664545. [PMID: 34307349 PMCID: PMC8294092 DOI: 10.3389/fcell.2021.664545] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 05/28/2021] [Indexed: 01/08/2023] Open
Abstract
It has been previously demonstrated that uniaxial cyclic stretching (UCS) induces differentiation of mesenchymal stem cells (MSCs) into osteoblasts in vitro. It is also known that interactions between cells and external forces occur at various aspects including cell–matrix, cytoskeleton, nucleus membrane, and chromatin. However, changes in chromatin landscape during this process are still not clear. The present study was aimed to determine changes of chromatin accessibility under cyclic stretch. The influence of cyclic stretching on the morphology, proliferation, and differentiation of hMSCs was characterized. Changes of open chromatin sites were determined by assay for transposase accessible chromatin with high-throughput sequencing (ATAC-seq). Our results showed that UCS induced cell reorientation and actin stress fibers realignment, and in turn caused nuclear reorientation and deformation. Compared with unstrained group, the expression of osteogenic and chondrogenic marker genes were the highest in group of 1 Hz + 8% strain; this condition also led to lower cell proliferation rate. Furthermore, there were 2022 gene loci with upregulated chromatin accessibility in 1 Hz + 8% groups based on the analysis of chromatin accessibility. These genes are associated with regulation of cell morphogenesis, cell–substrate adhesion, and ossification. Signaling pathways involved in osteogenic differentiation were found in up-regulated GO biological processes. These findings demonstrated that UCS increased the openness of gene loci associated with regulation of cell morphogenesis and osteogenesis as well as the corresponding transcription activities. Moreover, the findings also connect the changes in chromatin accessibility with cell reorientation, nuclear reorientation, and deformation. Our study may provide reference for directed differentiation of stem cells induced by mechanical microenvironments.
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Affiliation(s)
- Duo Zhang
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei, China
| | - Ran Zhang
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei, China
| | - Xiaoyuan Song
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Brain Function and Disease, Division of Life Sciences and Medicine, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Karen Chang Yan
- Mechanical Engineering and Biomedical Engineering, The College of New Jersey, Ewing Township, NJ, United States
| | - Haiyi Liang
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei, China
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13
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Kim J, Tamura A, Tsukita S, Park S. Uniaxial stretching device for studying maturity-dependent morphological response of epithelial cell monolayers to tensile strain. J IND ENG CHEM 2021. [DOI: 10.1016/j.jiec.2021.04.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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14
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Dessalles CA, Leclech C, Castagnino A, Barakat AI. Integration of substrate- and flow-derived stresses in endothelial cell mechanobiology. Commun Biol 2021; 4:764. [PMID: 34155305 PMCID: PMC8217569 DOI: 10.1038/s42003-021-02285-w] [Citation(s) in RCA: 77] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Accepted: 06/02/2021] [Indexed: 02/05/2023] Open
Abstract
Endothelial cells (ECs) lining all blood vessels are subjected to large mechanical stresses that regulate their structure and function in health and disease. Here, we review EC responses to substrate-derived biophysical cues, namely topography, curvature, and stiffness, as well as to flow-derived stresses, notably shear stress, pressure, and tensile stresses. Because these mechanical cues in vivo are coupled and are exerted simultaneously on ECs, we also review the effects of multiple cues and describe burgeoning in vitro approaches for elucidating how ECs integrate and interpret various mechanical stimuli. We conclude by highlighting key open questions and upcoming challenges in the field of EC mechanobiology.
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Affiliation(s)
- Claire A Dessalles
- LadHyX, CNRS, Ecole polytechnique, Institut polytechnique de Paris, Palaiseau, France
| | - Claire Leclech
- LadHyX, CNRS, Ecole polytechnique, Institut polytechnique de Paris, Palaiseau, France
| | - Alessia Castagnino
- LadHyX, CNRS, Ecole polytechnique, Institut polytechnique de Paris, Palaiseau, France
| | - Abdul I Barakat
- LadHyX, CNRS, Ecole polytechnique, Institut polytechnique de Paris, Palaiseau, France.
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15
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Danielsson BE, Tieu KV, Bathula K, Armiger TJ, Vellala PS, Taylor RE, Dahl KN, Conway DE. Lamin microaggregates lead to altered mechanotransmission in progerin-expressing cells. Nucleus 2021; 11:194-204. [PMID: 32816594 PMCID: PMC7529416 DOI: 10.1080/19491034.2020.1802906] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The nuclear lamina is a meshwork of intermediate filament proteins, and lamin A is the primary mechanical protein. An altered splicing of lamin A, known as progerin, causes the disease Hutchinson-Gilford progeria syndrome. Progerin-expressing cells have altered nuclear shapes and stiffened nuclear lamina with microaggregates of progerin. Here, progerin microaggregate inclusions in the lamina are shown to lead to cellular and multicellular dysfunction. We show with Comsol simulations that stiffened inclusions causes redistribution of normally homogeneous forces, and this redistribution is dependent on the stiffness difference and relatively independent of inclusion size. We also show mechanotransmission changes associated with progerin expression in cells under confinement and cells under external forces. Endothelial cells expressing progerin do not align properly with patterning. Fibroblasts expressing progerin do not align properly to applied cyclic force. Combined, these studies show that altered nuclear lamina mechanics and microstructure impacts cytoskeletal force transmission through the cell.
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Affiliation(s)
- Brooke E Danielsson
- Department of Biomedical Engineering, Virginia Commonwealth University , Richmond, VA, USA
| | - Katie V Tieu
- Department of Biomedical Engineering, Virginia Commonwealth University , Richmond, VA, USA
| | - Kranthidhar Bathula
- Department of Biomedical Engineering, Virginia Commonwealth University , Richmond, VA, USA
| | - Travis J Armiger
- Chemical Engineering, Carnegie Mellon University , Pittsburgh, PA, USA
| | - Pragna S Vellala
- Department of Biomedical Engineering, Carnegie Mellon University , Pittsburgh, PA , USA
| | - Rebecca E Taylor
- Department of Biomedical Engineering, Carnegie Mellon University , Pittsburgh, PA , USA.,Department of Mechanical Engineering, Carnegie Mellon University , Pittsburgh, PA, USA
| | - Kris Noel Dahl
- Chemical Engineering, Carnegie Mellon University , Pittsburgh, PA, USA.,Department of Biomedical Engineering, Carnegie Mellon University , Pittsburgh, PA , USA
| | - Daniel E Conway
- Department of Biomedical Engineering, Virginia Commonwealth University , Richmond, VA, USA
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16
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Dey K, Roca E, Ramorino G, Sartore L. Progress in the mechanical modulation of cell functions in tissue engineering. Biomater Sci 2021; 8:7033-7081. [PMID: 33150878 DOI: 10.1039/d0bm01255f] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In mammals, mechanics at multiple stages-nucleus to cell to ECM-underlie multiple physiological and pathological functions from its development to reproduction to death. Under this inspiration, substantial research has established the role of multiple aspects of mechanics in regulating fundamental cellular processes, including spreading, migration, growth, proliferation, and differentiation. However, our understanding of how these mechanical mechanisms are orchestrated or tuned at different stages to maintain or restore the healthy environment at the tissue or organ level remains largely a mystery. Over the past few decades, research in the mechanical manipulation of the surrounding environment-known as substrate or matrix or scaffold on which, or within which, cells are seeded-has been exceptionally enriched in the field of tissue engineering and regenerative medicine. To do so, traditional tissue engineering aims at recapitulating key mechanical milestones of native ECM into a substrate for guiding the cell fate and functions towards specific tissue regeneration. Despite tremendous progress, a big puzzle that remains is how the cells compute a host of mechanical cues, such as stiffness (elasticity), viscoelasticity, plasticity, non-linear elasticity, anisotropy, mechanical forces, and mechanical memory, into many biological functions in a cooperative, controlled, and safe manner. High throughput understanding of key cellular decisions as well as associated mechanosensitive downstream signaling pathway(s) for executing these decisions in response to mechanical cues, solo or combined, is essential to address this issue. While many reports have been made towards the progress and understanding of mechanical cues-particularly, substrate bulk stiffness and viscoelasticity-in regulating the cellular responses, a complete picture of mechanical cues is lacking. This review highlights a comprehensive view on the mechanical cues that are linked to modulate many cellular functions and consequent tissue functionality. For a very basic understanding, a brief discussion of the key mechanical players of ECM and the principle of mechanotransduction process is outlined. In addition, this review gathers together the most important data on the stiffness of various cells and ECM components as well as various tissues/organs and proposes an associated link from the mechanical perspective that is not yet reported. Finally, beyond addressing the challenges involved in tuning the interplaying mechanical cues in an independent manner, emerging advances in designing biomaterials for tissue engineering are also explored.
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Affiliation(s)
- Kamol Dey
- Department of Applied Chemistry and Chemical Engineering, Faculty of Science, University of Chittagong, Bangladesh
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17
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Huang W, Matsui TS, Saito T, Kuragano M, Takahashi M, Kawahara T, Sato M, Deguchi S. Mechanosensitive myosin II but not cofilin primarily contributes to cyclic cell stretch-induced selective disassembly of actin stress fibers. Am J Physiol Cell Physiol 2021; 320:C1153-C1163. [PMID: 33881935 DOI: 10.1152/ajpcell.00225.2020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cells adapt to applied cyclic stretch (CS) to circumvent chronic activation of proinflammatory signaling. Currently, the molecular mechanism of the selective disassembly of actin stress fibers (SFs) in the stretch direction, which occurs at the early stage of the cellular response to CS, remains controversial. Here, we suggest that the mechanosensitive behavior of myosin II, a major cross-linker of SFs, primarily contributes to the directional disassembly of the actomyosin complex SFs in bovine vascular smooth muscle cells and human U2OS osteosarcoma cells. First, we identified that CS with a shortening phase that exceeds in speed the inherent contractile rate of individual SFs leads to the disassembly. To understand the biological basis, we investigated the effect of expressing myosin regulatory light-chain mutants and found that SFs with less actomyosin activities disassemble more promptly upon CS. We consequently created a minimal mathematical model that recapitulates the salient features of the direction-selective and threshold-triggered disassembly of SFs to show that disassembly or, more specifically, unbundling of the actomyosin bundle SFs is enhanced with sufficiently fast cell shortening. We further demonstrated that similar disassembly of SFs is inducible in the presence of an active LIM-kinase-1 mutant that deactivates cofilin, suggesting that cofilin is dispensable as opposed to a previously proposed mechanism.
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Affiliation(s)
- Wenjing Huang
- Department of Bioengineering, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
| | - Tsubasa S Matsui
- Division of Bioengineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Japan
| | - Takumi Saito
- Division of Bioengineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Japan
| | - Masahiro Kuragano
- Graduate School of Chemical Science and Engineering, Hokkaido University, Sapporo, Japan
| | - Masayuki Takahashi
- Graduate School of Chemical Science and Engineering, Hokkaido University, Sapporo, Japan
| | - Tomohiro Kawahara
- Department of Biological Functions Engineering, Kyushu Institute of Technology, Kitakyushu, Japan
| | - Masaaki Sato
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan
| | - Shinji Deguchi
- Division of Bioengineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Japan
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18
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Mao T, He Y, Gu Y, Yang Y, Yu Y, Wang X, Ding J. Critical Frequency and Critical Stretching Rate for Reorientation of Cells on a Cyclically Stretched Polymer in a Microfluidic Chip. ACS APPLIED MATERIALS & INTERFACES 2021; 13:13934-13948. [PMID: 33739805 DOI: 10.1021/acsami.0c21186] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The ability of cells to sense and respond to mechanical signals from their surrounding microenvironments is one of the key issues in tissue engineering and regeneration, yet a fundamental study of cells with both cell observation and mechanical stimulus is challenging and should be based upon an appropriate microdevice. Herein we designed and fabricated a two-layer microfluidic chip to enable simultaneous observation of live cells and cyclic stretching of an elastic polymer, polydimethylsiloxane (PDMS), with a modified surface for enhanced cell adhesion. Human mesenchymal stem cells (hMSCs) were examined with a series of frequencies from 0.00003 to 2 Hz and varied amplitudes of 2%, 5%, or 10%. The cells with an initial random orientation were confirmed to be reoriented perpendicular to the stretching direction at frequencies greater than a threshold value, which we term critical frequency (fc); additionally, the critical frequency fc was amplitude-dependent. We further introduced the concept of critical stretching rate (Rc) and found that this quantity can unify both frequency and amplitude dependences. The reciprocal value of Rc in this study reads 8.3 min, which is consistent with the turnover time of actin filaments reported in the literature, suggesting that the supramolecular relaxation in the cytoskeleton within a cell might be responsible for the underlying cell mechanotransduction. The theoretical calculation of cell reorientation based on a two-dimensional tensegrity model under uniaxial cyclic stretching is well consistent with our experiments. The above findings provide new insight into the crucial role of critical frequency and critical stretching rate in regulating cells on biomaterials under biomechanical stimuli.
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Affiliation(s)
- Tianjiao Mao
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200438, China
| | - Yingning He
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200438, China
| | - Yexin Gu
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200438, China
| | - Yuqian Yang
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200438, China
| | - Yue Yu
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200438, China
| | - Xinlei Wang
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200438, China
| | - Jiandong Ding
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200438, China
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19
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A Fully Integrated Arduino-Based System for the Application of Stretching Stimuli to Living Cells and Their Time-Lapse Observation: A Do-It-Yourself Biology Approach. Ann Biomed Eng 2021; 49:2243-2259. [PMID: 33728867 DOI: 10.1007/s10439-021-02758-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 02/20/2021] [Indexed: 10/21/2022]
Abstract
Mechanobiology has nowadays acquired the status of a topic of fundamental importance in a degree in Biological Sciences. It is inherently a multidisciplinary topic where biology, physics and engineering competences are required. A course in mechanobiology should include lab experiences where students can appreciate how mechanical stimuli from outside affect living cell behaviour. Here we describe all the steps to build a cell stretcher inside an on-stage cell incubator. This device allows exposing living cells to a periodic mechanical stimulus similar to what happens in physiological conditions such as, for example, in the vascular system or in the lungs. The reaction of the cells to the periodic mechanical stretching represents a prototype of a mechanobiological signal integrated by living cells. We also provide the theoretical and experimental aspects related to the calibration of the stretcher apparatus at a level accessible to researchers not used to dealing with topics like continuum mechanics and analysis of deformations. We tested our device by stretching cells of two different lines, U87-MG and Balb-3T3 cells, and we analysed and discussed the effect of the periodic stimulus on both cell reorientation and migration. We also discuss the basic aspects related to the quantitative analysis of the reorientation process and of cell migration. We think that the device we propose can be easily reproduced at low-cost within a project-oriented course in the fields of biology, biotechnology and medical engineering.
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20
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Pakravan HA, Saidi MS, Firoozabadi B. Endothelial Cells Morphology in Response to Combined WSS and Biaxial CS: Introduction of Effective Strain Ratio. Cell Mol Bioeng 2020; 13:647-657. [PMID: 33281993 DOI: 10.1007/s12195-020-00618-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Accepted: 05/05/2020] [Indexed: 11/24/2022] Open
Abstract
Introduction Endothelial cells (ECs) morphology strongly depends on the imposed mechanical stimuli. These mechanical stimuli include wall shear stress (WSS) and biaxial cyclic stretches (CS). Under combined loading, the effect of CS is not as simple as pure CS. The present study investigates the morphological response of ECs to the realistic mechanical stimuli. Methods The cell population is theoretically studied using our previous validated model. The mechanical stimuli on ECs are described using four parameters; WSS magnitude (0 to 2.0 Pa), WSS angle (- 50° to 50°), and biaxial CS in two perpendicular directions (0 to 10%). The morphology of ECs is reported using four parameters; average shape index (SI) and orientation angle (OA) of the cell population as well as the standard deviation (SD) of SI and OA as measures for scattering of cells' SI and OA from these average values. Results A new effective strain ratio (ESR) is defined as the ratio of the undesirable CS to the desirable one. The obtained results of the model, illustrated that the SI and OA of cells increase with absolute value of ESR. In addition, the scattering in the SI of cells decreases with the absolute value of ESR, which means that the cell shapes become more regular. It is shown that the angular irregularity of cells increases at higher ESR values. Conclusions The results indicated that, the defined ESR is a stand-alone parameter for describing the realistic mechanical loading on the ECs and their morphological response.
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Affiliation(s)
| | - Mohammad Said Saidi
- Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran
| | - Bahar Firoozabadi
- Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran
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21
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Kaunas R. Good advice for endothelial cells: Get in line, relax tension, and go with the flow. APL Bioeng 2020; 4:010905. [PMID: 32128470 PMCID: PMC7044000 DOI: 10.1063/1.5129812] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 01/19/2020] [Indexed: 11/26/2022] Open
Abstract
Endothelial cells (ECs) are continuously subjected to fluid wall shear stress (WSS) and cyclic strain caused by pulsatile blood flow and pressure. It is well established that these hemodynamic forces each play important roles in vascular disease, but their combined effects are not well understood. ECs remodel in response to both WSS and cyclic strain to align along the vessel axis, but in areas prone to atherogenesis, such an alignment is absent. In this perspective, experimental and clinical findings will be reviewed, which have revealed the characteristics of WSS and cyclic strain, which are associated with atherosclerosis, spanning studies on whole blood vessels to individual cells to mechanosensing molecules. Examples are described regarding the use of computational modeling to elucidate the mechanisms by which EC alignment contributes to mechanical homeostasis. Finally, the need to move toward an integrated understanding of how hemodynamic forces influence EC mechanotransduction is presented, which holds the potential to move our currently fragmented understanding to a true appreciation of the role of mechanical stimuli in atherosclerosis.
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Affiliation(s)
- Roland Kaunas
- Department of Biomedical Engineering and Department of Cellular and Molecular Medicine, Texas A&M University, College Station, Texas 77843-3120, USA
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22
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Helical structure of actin stress fibers and its possible contribution to inducing their direction-selective disassembly upon cell shortening. Biomech Model Mechanobiol 2019; 19:543-555. [PMID: 31549258 DOI: 10.1007/s10237-019-01228-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 09/10/2019] [Indexed: 12/21/2022]
Abstract
Mechanisms of the assembly of actin stress fibers (SFs) have been extensively studied, while those of the disassembly-particularly cell shortening-induced ones-remain unclear. Here, we show that SFs have helical structures composed of multi-subbundles, and they tend to be delaminated upon cell shortening. Specifically, we observed with atomic force microscopy delamination of helical SFs into their subbundles. We physically caught individual SFs using a pair of glass needles to observe rotational deformations during stretching as well as ATP-driven active contraction, suggesting that they deform in a manner reflecting their intrinsic helical structure. A minimal analytical model was then developed based on the Frenet-Serret formulas with force-strain measurement data to suggest that helical SFs can be delaminated into the constituent subbundles upon axial shortening. Given that SFs are large molecular clusters that bear cellular tension but must promptly disassemble upon loss of the tension, the resulting increase in their surface area due to the shortening-induced delamination may facilitate interaction with surrounding molecules to aid subsequent disintegration. Thus, our results suggest a new mechanism of the disassembly that occurs only in the specific SFs exposed to forced shortening.
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23
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Kumar A, Shutova MS, Tanaka K, Iwamoto DV, Calderwood DA, Svitkina TM, Schwartz MA. Filamin A mediates isotropic distribution of applied force across the actin network. J Cell Biol 2019; 218:2481-2491. [PMID: 31315944 PMCID: PMC6683746 DOI: 10.1083/jcb.201901086] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 05/03/2019] [Accepted: 06/17/2019] [Indexed: 12/02/2022] Open
Abstract
In this work, Kumar et al. use their previously developed talin tension sensor to study the immediate response of cells to uniaxial stretch. Tension measurements together with high-resolution electron microscopy reveal a novel role for the actin cross-linking protein filamin A in mediating tensional symmetry within the F-actin network. Cell sensing of externally applied mechanical strain through integrin-mediated adhesions is critical in development and physiology of muscle, lung, tendon, and arteries, among others. We examined the effects of strain on force transmission through the essential cytoskeletal linker talin. Using a fluorescence-based talin tension sensor (TS), we found that uniaxial stretch of cells on elastic substrates increased tension on talin, which was unexpectedly independent of the orientation of the focal adhesions relative to the direction of strain. High-resolution electron microscopy of the actin cytoskeleton revealed that stress fibers (SFs) are integrated into an isotropic network of cortical actin filaments in which filamin A (FlnA) localizes preferentially to points of intersection between SFs and cortical actin. Knockdown (KD) of FlnA resulted in more isolated, less integrated SFs. After FlnA KD, tension on talin was polarized in the direction of stretch, while FlnA reexpression restored tensional symmetry. These data demonstrate that a FlnA-dependent cortical actin network distributes applied forces over the entire cytoskeleton–matrix interface.
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Affiliation(s)
- Abhishek Kumar
- Yale Cardiovascular Research Center, Yale University School of Medicine, New Haven, CT
| | - Maria S Shutova
- Department of Biology, University of Pennsylvania, Philadelphia, PA
| | - Keiichiro Tanaka
- Yale Cardiovascular Research Center, Yale University School of Medicine, New Haven, CT
| | | | - David A Calderwood
- Department of Pharmacology, Yale University, New Haven, CT.,Department of Cell Biology, Yale University, New Haven, CT
| | | | - Martin A Schwartz
- Yale Cardiovascular Research Center, Yale University School of Medicine, New Haven, CT .,Department of Cell Biology, Yale University, New Haven, CT.,Department of Biomedical Engineering, Yale University, New Haven, CT
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24
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Springer R, Zielinski A, Pleschka C, Hoffmann B, Merkel R. Unbiased pattern analysis reveals highly diverse responses of cytoskeletal systems to cyclic straining. PLoS One 2019; 14:e0210570. [PMID: 30865622 PMCID: PMC6415792 DOI: 10.1371/journal.pone.0210570] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 12/26/2018] [Indexed: 01/09/2023] Open
Abstract
In mammalian cells, actin, microtubules, and various types of cytoplasmic intermediate filaments respond to external stretching. Here, we investigated the underlying processes in endothelial cells plated on soft substrates from silicone elastomer. After cyclic stretch (0.13 Hz, 14% strain amplitude) for periods ranging from 5 min to 8 h, cells were fixed and double-stained for microtubules and either actin or vimentin. Cell images were analyzed by a two-step routine. In the first step, micrographs were segmented for potential fibrous structures. In the second step, the resulting binary masks were auto- or cross-correlated. Autocorrelation of segmented images provided a sensitive and objective measure of orientational and translational order of the different cytoskeletal systems. Aligning of correlograms from individual cells removed the influence of only partial alignment between cells and enabled determination of intrinsic cytoskeletal order. We found that cyclic stretching affected the actin cytoskeleton most, microtubules less, and vimentin mostly only via reorientation of the whole cell. Pharmacological disruption of microtubules had barely any influence on actin ordering. The similarity, i.e., cross-correlation, between vimentin and microtubules was much higher than the one between actin and microtubules. Moreover, prolonged cyclic stretching slightly decoupled the cytoskeletal systems as it reduced the cross-correlations in both cases. Finally, actin and microtubules were more correlated at peripheral regions of cells whereas vimentin and microtubules correlated more in central regions.
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Affiliation(s)
- Ronald Springer
- Institute of Complex Systems 7, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Alexander Zielinski
- Institute of Complex Systems 7, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Catharina Pleschka
- Institute of Complex Systems 7, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Bernd Hoffmann
- Institute of Complex Systems 7, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Rudolf Merkel
- Institute of Complex Systems 7, Forschungszentrum Jülich GmbH, Jülich, Germany
- * E-mail:
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25
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Molina JJ, Yamamoto R. Modeling the mechanosensitivity of fast-crawling cells on cyclically stretched substrates. SOFT MATTER 2019; 15:683-698. [PMID: 30623962 DOI: 10.1039/c8sm01903g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The mechanosensitivity of cells, which determines how they are able to respond to mechanical signals, is crucial for the functioning of biological systems. Experimentally, this is investigated by studying the reorientation of cells on cyclically stretched substrates. The reorientation depends on the type of cell and on the stretching protocol, but the mechanisms responsible for the response are still not completely understood. Here, we introduce a computational model for fast crawling cells on cyclically stretched substrates that accounts for the sub-cellular elements responsible for cell shape and motility. This includes the dynamics of the cell membrane, the actin cytoskeleton, and the focal adhesions with the stretching substrate. These processes evolve over characteristic time scales that can vary by orders of magnitude and naturally give rise to the frequency dependent reorientation observed experimentally. Depending on which processes are being probed by the stretching and on the type of coupling with the substrate, our simulations predict either no reorientation, a bi-stability in the parallel and perpendicular directions, or a complete reorientation in either the parallel or perpendicular direction. In particular, we show that an asymmetry in the adhesion dynamics during the loading and unloading phases of the stretching, whether it comes from the response of the cell itself or from the precise stretching protocol, can be used to selectively align the cells. Our results provide further evidence for the importance of focal adhesion dynamics in determining the mechanosensitive response of cells, as well as a way to interpret recent experiments.
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Affiliation(s)
- John J Molina
- Department of Chemical Engineering, Kyoto University, Kyoto, Japan.
| | - Ryoichi Yamamoto
- Department of Chemical Engineering, Kyoto University, Kyoto, Japan. and Institute of Industrial Science, The University of Tokyo, Tokyo, 153-8505, Japan
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26
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Russo TA, Stoll D, Nader HB, Dreyfuss JL. Mechanical stretch implications for vascular endothelial cells: Altered extracellular matrix synthesis and remodeling in pathological conditions. Life Sci 2018; 213:214-225. [PMID: 30343127 DOI: 10.1016/j.lfs.2018.10.030] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 10/09/2018] [Accepted: 10/17/2018] [Indexed: 10/28/2022]
Abstract
AIMS Cardiovascular diseases such as hypertension, thrombosis and atherosclerosis are responses to mechanical forces applied to the endothelium. Endothelial cells respond to hemodynamic mechanical forces such as cellular mechanical stretching. We investigated the expression of glycosaminoglycans, proteoglycans and other extracellular matrix molecules in endothelial cells subjected to various mechanical stimuli. MAIN METHODS Endothelial cells were subjected to mechanical stretch in a vacuum system FlexCell™ to 5% (physiological condition) and 15% (pathological condition), for 4 h or 24 h. Culture plates not subjected to strain were used as controls. Subsequently, ECs were subjected to immunofluorescence, real-time PCR, PCR array, glycosaminoglycans biosynthesis using metabolic radiolabeling with 35S-sulfate and cell behavior assays (adhesion, migration and capillary tube formation). KEY FINDINGS Mechanical stretch induced changes in endothelial cell morphology. Pathological consequences of mechanical stretch included inhibited migration in 2-fold and capillary-like tube formation in 2-fold, when compared to physiological condition after 4 h of ECs exposure; it also reduced total sulfated glycosaminoglycans synthesis thereabout 1.5-fold. Pathological mechanical stretch conditions induced higher expression after 24 h of ECs exposure to mechanical stretch of syndecan-4 (3.5-fold), perlecan (9.1-fold), decorin (5.7-fold), adhesive proteins as fibronectin (5.6-fold) and collagen III α1 (2.2-fold) and growth factors, including VEGF-A (7.3-fold) and TGFβ-1 (14.6-fold) and TGFβ-3 (4.3-fold). SIGNIFICANCE Exposure of endothelial cells to mechanical stretch influenced remodeling of the extracellular matrix as well as cell-matrix interactions. These studies improve understanding of how vascular biology is affected by mechanical forces and how these molecules behave in cardiovascular diseases.
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Affiliation(s)
- T A Russo
- Department of Biochemistry, Molecular Biology Division, Carl Peter von Dietrich Laboratory, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil
| | - D Stoll
- Department of Nephrology, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil
| | - H B Nader
- Department of Biochemistry, Molecular Biology Division, Carl Peter von Dietrich Laboratory, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil
| | - J L Dreyfuss
- Department of Biochemistry, Molecular Biology Division, Carl Peter von Dietrich Laboratory, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil..
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27
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Zielinski A, Linnartz C, Pleschka C, Dreissen G, Springer R, Merkel R, Hoffmann B. Reorientation dynamics and structural interdependencies of actin, microtubules and intermediate filaments upon cyclic stretch application. Cytoskeleton (Hoboken) 2018; 75:385-394. [DOI: 10.1002/cm.21470] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 05/18/2018] [Accepted: 06/01/2018] [Indexed: 12/17/2022]
Affiliation(s)
- Alexander Zielinski
- Forschungszentrum Jülich, Institute of Complex Systems, ICS-7: Biomechanics; Jülich Germany
| | - Christina Linnartz
- Forschungszentrum Jülich, Institute of Complex Systems, ICS-7: Biomechanics; Jülich Germany
| | - Catharina Pleschka
- Forschungszentrum Jülich, Institute of Complex Systems, ICS-7: Biomechanics; Jülich Germany
| | - Georg Dreissen
- Forschungszentrum Jülich, Institute of Complex Systems, ICS-7: Biomechanics; Jülich Germany
| | - Ronald Springer
- Forschungszentrum Jülich, Institute of Complex Systems, ICS-7: Biomechanics; Jülich Germany
| | - Rudolf Merkel
- Forschungszentrum Jülich, Institute of Complex Systems, ICS-7: Biomechanics; Jülich Germany
| | - Bernd Hoffmann
- Forschungszentrum Jülich, Institute of Complex Systems, ICS-7: Biomechanics; Jülich Germany
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28
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Okimura C, Sakumura Y, Shimabukuro K, Iwadate Y. Sensing of substratum rigidity and directional migration by fast-crawling cells. Phys Rev E 2018; 97:052401. [PMID: 29906928 DOI: 10.1103/physreve.97.052401] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Indexed: 12/24/2022]
Abstract
Living cells sense the mechanical properties of their surrounding environment and respond accordingly. Crawling cells detect the rigidity of their substratum and migrate in certain directions. They can be classified into two categories: slow-moving and fast-moving cell types. Slow-moving cell types, such as fibroblasts, smooth muscle cells, mesenchymal stem cells, etc., move toward rigid areas on the substratum in response to a rigidity gradient. However, there is not much information on rigidity sensing in fast-moving cell types whose size is ∼10 μm and migration velocity is ∼10 μm/min. In this study, we used both isotropic substrata with different rigidities and an anisotropic substratum that is rigid on the x axis but soft on the y axis to demonstrate rigidity sensing by fast-moving Dictyostelium cells and neutrophil-like differentiated HL-60 cells. Dictyostelium cells exerted larger traction forces on a more rigid isotropic substratum. Dictyostelium cells and HL-60 cells migrated in the "soft" direction on the anisotropic substratum, although myosin II-null Dictyostelium cells migrated in random directions, indicating that rigidity sensing of fast-moving cell types differs from that of slow types and is induced by a myosin II-related process.
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Affiliation(s)
- Chika Okimura
- Faculty of Science, Yamaguchi University, Yamaguchi 753-8512, Japan
| | - Yuichi Sakumura
- School of Information Science and Technology, Aichi Prefectural University, Aichi 480-1198, Japan.,Graduate School of Science and Technology, Nara Institute of Science and Technology, Nara, 630-0192, Japan
| | - Katsuya Shimabukuro
- Department of Chemical and Biological Engineering, National Institute of Technology, Ube College, Ube 755-8555, Japan
| | - Yoshiaki Iwadate
- Faculty of Science, Yamaguchi University, Yamaguchi 753-8512, Japan
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29
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Matsui TS, Wu H, Deguchi S. Deformable 96-well cell culture plate compatible with high-throughput screening platforms. PLoS One 2018; 13:e0203448. [PMID: 30188938 PMCID: PMC6126838 DOI: 10.1371/journal.pone.0203448] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 07/03/2018] [Indexed: 12/22/2022] Open
Abstract
Adherent cells such as endothelial cells sense applied mechanical stretch to adapt to changes in their surrounding mechanical environment. Despite numerous studies, signaling pathways underlying the cellular mechanosensing and adaptation remain to be fully elucidated partly because of the lack of tools that allow for a comprehensive screening approach. Conventionally, multi-well cell culture plates of standard configurations are used for comprehensive analyses in cell biology study to identify key molecules in a high-throughput manner. Given that situation, here we design a 96-well cell culture plate made of elastic silicone and mechanically stretchable using a motorized device. Computational analysis suggested that highly uniform stretch can be applied to each of the wells other than the peripheral wells. Elastic image registration-based experimental evaluation on stretch distributions within individual wells revealed the presence of larger variations among wells compared to those in the computational analysis, but a stretch level of 10%–that has been employed in conventional studies on cellular response to stretch—was almost achieved with our setup. We exposed vascular smooth muscle cells to cyclic stretch using the device to demonstrate morphological repolarization of the cells, i.e. typical cellular response to cyclic stretch. Because the deformable multi-well plate validated here is compatible with other high-throughput screening-oriented technologies, we expect this novel system to be utilized for future comprehensive analyses of stretch-related signaling pathways.
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Affiliation(s)
- Tsubasa S Matsui
- Division of Bioengineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, Japan.,Department of Nanopharmaceutical Sciences, Nagoya Institute of Technology, Nagoya, Aichi, Japan
| | - Hugejile Wu
- Department of Nanopharmaceutical Sciences, Nagoya Institute of Technology, Nagoya, Aichi, Japan
| | - Shinji Deguchi
- Division of Bioengineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, Japan.,Department of Nanopharmaceutical Sciences, Nagoya Institute of Technology, Nagoya, Aichi, Japan
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30
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Wirshing ACE, Cram EJ. Spectrin regulates cell contractility through production and maintenance of actin bundles in the Caenorhabditis elegans spermatheca. Mol Biol Cell 2018; 29:2433-2449. [PMID: 30091661 PMCID: PMC6233056 DOI: 10.1091/mbc.e18-06-0347] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Disruption to the contractility of cells, including smooth muscle cells of the cardiovascular system and myoepithelial cells of the glandular epithelium, contributes to the pathophysiology of contractile tissue diseases, including asthma, hypertension, and primary Sjögren's syndrome. Cell contractility is determined by myosin activity and actomyosin network organization and is mediated by hundreds of protein-protein interactions, many directly involving actin. Here we use a candidate RNA interference screen of more than 100 Caenorhabditis elegans genes with predicted actin-binding and regulatory domains to identify genes that contribute to the contractility of the somatic gonad. We identify the spectrin cytoskeleton composed of SPC-1/α-spectrin, UNC-70/β-spectrin, and SMA-1/β heavy-spectrin as required for contractility and actin organization in the myoepithelial cells of the C. elegans spermatheca. We use imaging of fixed and live animals as well as tissue- and developmental-stage-specific disruption of the spectrin cytoskeleton to show that spectrin regulates the production of prominent central actin bundles and is required for maintenance of central actin bundles throughout successive rounds of stretch and contraction. We conclude that the spectrin cytoskeleton contributes to spermathecal contractility by promoting maintenance of the robust actomyosin bundles that drive contraction.
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Affiliation(s)
| | - Erin J Cram
- Department of Biology, Northeastern University, Boston, MA 02115
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31
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Kelley CA, Wirshing ACE, Zaidel-Bar R, Cram EJ. The myosin light-chain kinase MLCK-1 relocalizes during Caenorhabditis elegans ovulation to promote actomyosin bundle assembly and drive contraction. Mol Biol Cell 2018; 29:1975-1991. [PMID: 30088798 PMCID: PMC6232974 DOI: 10.1091/mbc.e18-01-0056] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
We identify the Caenorhabditis elegans myosin light-chain kinase, MLCK-1, required for contraction of spermathecae. During contraction, MLCK-1 moves from the apical cell boundaries to the basal actomyosin bundles, where it stabilizes myosin downstream of calcium signaling. MLCK and ROCK act in distinct subsets of cells to coordinate the timing of contraction.
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Affiliation(s)
| | | | - Ronen Zaidel-Bar
- Department of Cell and Developmental Biology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv 69978, Israel
| | - Erin J Cram
- Department of Biology, Northeastern University, Boston, MA 02115
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32
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Minami K, Hayashi T, Sato K, Nakahara T. Development of micro mechanical device having two-dimensional array of micro chambers for cell stretching. Biomed Microdevices 2018; 20:10. [PMID: 29305659 DOI: 10.1007/s10544-017-0256-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
This paper presents a novel cell stretching micro device having two-dimensional array of micro chambers. It enables an in situ time-lapse observation of stretched cell by using an optical microscope with high measurement efficiency. The presented device consists of a cell culture dish and the array of micro chambers made of silicone elastomer and extension structures made of photocurable resin, and is fabricated with MEMS technology. The fabrication process of the thin micro chamber array combines photoresist mold and lift-off process based on conventional photolithography. The fabricated device has 134micro chambers in 5μm or less thickness. It was demonstrated that the fabricated micro device could be used to make in-situ time-lapse observation of cell responses to stretching under optical microscopy. In addition, the influence of the chamber thickness to the quality of the microscope image observed was evaluated. It is confirmed that the proposed device having two-dimensional array of the thin micro chambers makes it possible to observe cell response for stretch stimuli with high quality and efficiency.
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Affiliation(s)
- K Minami
- Graduate School of Sciences and Technology for Innovation, Yamaguchi University, 2-6-1 Tokiwadai, Ube, Yamaguchi, 755-8611, Japan.
| | - T Hayashi
- Graduate School of Sciences and Technology for Innovation, Yamaguchi University, 2-6-1 Tokiwadai, Ube, Yamaguchi, 755-8611, Japan
| | - K Sato
- Graduate School of Technology, Industrial and Social Sciences, Tokushima University, 2-1 Minami Josanjima, Tokushima, Tokushima, 770-8506, Japan
| | - T Nakahara
- Graduate School of Sciences and Technology for Innovation, Yamaguchi University, 2-6-1 Tokiwadai, Ube, Yamaguchi, 755-8611, Japan
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33
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Pakravan HA, Saidi MS, Firoozabadi B. A multiscale approach for determining the morphology of endothelial cells at a coronary artery. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2017; 33. [PMID: 28445003 DOI: 10.1002/cnm.2891] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 04/11/2017] [Accepted: 04/23/2017] [Indexed: 06/07/2023]
Abstract
The morphology of endothelial cells (ECs) may be an indication for determining atheroprone sites. Until now, there has been no clinical imaging technique to visualize the morphology of ECs in the arteries. The present study introduces a computational technique for determining the morphology of ECs. This technique is a multiscale simulation consisting of the artery scale and the cell scale. The artery scale is a fluid-structure interaction simulation. The input for the artery scale is the geometry of the coronary artery, that is, the dynamic curvature of the artery due to the cardiac motion, blood flow, blood pressure, heart rate, and the mechanical properties of the blood and the arterial wall, the measurements of which can be obtained for a specific patient. The results of the artery scale are wall shear stress (WSS) and cyclic strains as the mechanical stimuli of ECs. The cell scale is an inventive mass-and-spring model that is able to determine the morphological response of ECs to any combination of mechanical stimuli. The results of the multiscale simulation show the morphology of ECs at different locations of the coronary artery. The results indicate that the atheroprone sites have at least 1 of 3 factors: low time-averaged WSS, high angle of WSS, and high longitudinal strain. The most probable sites for atherosclerosis are located at the bifurcation region and lie on the myocardial side of the artery. The results also indicated that a higher dynamic curvature is a negative factor and a higher pulse pressure is a positive factor for protection against atherosclerosis.
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Affiliation(s)
- Hossein Ali Pakravan
- Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran
- Department of Mechanical Engineering, Shiraz University, Shiraz, Iran
| | - Mohammad Said Saidi
- Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran
| | - Bahar Firoozabadi
- Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran
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34
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Wu Y, Zhuang J, Zhao D, Zhang F, Ma J, Xu C. Cyclic stretch-induced the cytoskeleton rearrangement and gene expression of cytoskeletal regulators in human periodontal ligament cells. Acta Odontol Scand 2017; 75:507-516. [PMID: 28681629 DOI: 10.1080/00016357.2017.1347823] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
OBJECTIVE This study aimed to explore the mechanism of the stretch-induced cell realignment and cytoskeletal rearrangement by identifying several mechanoresponsive genes related to cytoskeletal regulators in human PDL cells. MATERIAL AND METHODS After the cells were stretched by 1, 10 and 20% strains for 0.5, 1, 2, 4, 6, 12 or 24 h, the changes of the morphology and content of microfilaments were recorded and calculated. Meanwhile, the expression of 84 key genes encoding cytoskeletal regulators after 6 and 24 h stretches with 20% strain was detected by using real-time PCR array. Western blot was applied to identify the protein expression level of several cytoskeletal regulators encoded by these differentially expressed genes. RESULTS The confocal fluorescent staining results confirmed that stretch-induced realignment of cells and rearrangement of microfilaments. Among the 84 genes screened, one gene was up-regulated while two genes were down-regulated after 6 h stretch. Meanwhile, three genes were up-regulated while two genes were down-regulated after 24 h stretch. These genes displaying differential expression included genes regulating polymerization/depolymerization of microfilaments (CDC42EP2, FNBP1L, NCK2, PIKFYVE, WASL), polymerization/depolymerization of microtubules (STMN1), interacting between microfilaments and microtubules (MACF1), as well as a phosphatase (PPP1R12B). Among the proteins encoded by these genes, the protein expression level of Cdc42 effector protein-2 (encoded by CDC42EP2) and Stathmin-1 (encoded by STMN1) was down-regulated, while the protein expression level of N-WASP (encoded by WASL) was up-regulated. CONCLUSION The present study confirmed the cyclic stretch-induced cellular realignment and rearrangement of microfilaments in the human PDL cells and indicated several force-sensitive genes with regard to cytoskeletal regulators.
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Affiliation(s)
- Yaqin Wu
- Department of Prosthodontics, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China
| | - Jiabao Zhuang
- Department of Prosthodontics, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China
| | - Dan Zhao
- Department of Prosthodontics, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China
| | - Fuqiang Zhang
- Department of Prosthodontics, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China
| | - Jiayin Ma
- Department of Prosthodontics, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China
| | - Chun Xu
- Department of Prosthodontics, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China
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35
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van Haaften EE, Bouten CVC, Kurniawan NA. Vascular Mechanobiology: Towards Control of In Situ Regeneration. Cells 2017; 6:E19. [PMID: 28671618 PMCID: PMC5617965 DOI: 10.3390/cells6030019] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Revised: 06/16/2017] [Accepted: 06/23/2017] [Indexed: 01/08/2023] Open
Abstract
The paradigm of regenerative medicine has recently shifted from in vitro to in situ tissue engineering: implanting a cell-free, biodegradable, off-the-shelf available scaffold and inducing the development of functional tissue by utilizing the regenerative potential of the body itself. This approach offers a prospect of not only alleviating the clinical demand for autologous vessels but also circumventing the current challenges with synthetic grafts. In order to move towards a hypothesis-driven engineering approach, we review three crucial aspects that need to be taken into account when regenerating vessels: (1) the structure-function relation for attaining mechanical homeostasis of vascular tissues, (2) the environmental cues governing cell function, and (3) the available experimental platforms to test instructive scaffolds for in situ tissue engineering. The understanding of cellular responses to environmental cues leads to the development of computational models to predict tissue formation and maturation, which are validated using experimental platforms recapitulating the (patho)physiological micro-environment. With the current advances, a progressive shift is anticipated towards a rational and effective approach of building instructive scaffolds for in situ vascular tissue regeneration.
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Affiliation(s)
- Eline E van Haaften
- Department of Biomedical Engineering, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.
- Institute for Complex Molecular Systems, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.
| | - Carlijn V C Bouten
- Department of Biomedical Engineering, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.
- Institute for Complex Molecular Systems, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.
| | - Nicholas A Kurniawan
- Department of Biomedical Engineering, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.
- Institute for Complex Molecular Systems, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.
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36
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Wirshing ACE, Cram EJ. Myosin activity drives actomyosin bundle formation and organization in contractile cells of the Caenorhabditis elegans spermatheca. Mol Biol Cell 2017; 28:1937-1949. [PMID: 28331075 PMCID: PMC5541844 DOI: 10.1091/mbc.e17-01-0029] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 03/14/2017] [Accepted: 03/17/2017] [Indexed: 12/04/2022] Open
Abstract
The contractile myoepithelial cells of the Caenorhabditis elegans somatic gonad are stretched by oocyte entry and subsequently contract to expel the fertilized embryo into the uterus. Formation of aligned, parallel actomyosin bundles during the first ovulation is triggered by oocyte entry and regulated by myosin contractility. Stress fibers—contractile actomyosin bundles—are important for cellular force production and adaptation to physical stress and have been well studied within the context of cell migration. However, less is known about actomyosin bundle formation and organization in vivo and in specialized contractile cells, such as smooth muscle and myoepithelial cells. The Caenorhabditis elegans spermatheca is a bag-like organ of 24 myoepithelial cells that houses the sperm and is the site of fertilization. During ovulation, spermathecal cells are stretched by oocyte entry and then coordinately contract to expel the fertilized embryo into the uterus. Here we use four-dimensional confocal microscopy of live animals to observe changes to spermathecal actomyosin network organization during cell stretch and contraction. Oocyte entry is required to trigger cell contraction and concomitant production of parallel actomyosin bundles. Actomyosin bundle size, connectivity, spacing, and orientation are regulated by myosin activity. We conclude that myosin drives actomyosin bundle production and that myosin activity is tightly regulated during ovulation to produce an optimally organized actomyosin network in C. elegans spermathecae.
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Affiliation(s)
| | - Erin J Cram
- Department of Biology, Northeastern University, Boston, MA 02115
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37
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Tamiello C, Halder M, Kamps MAF, Baaijens FPT, Broers JLV, Bouten CVC. Cellular strain avoidance is mediated by a functional actin cap - observations in an Lmna-deficient cell model. J Cell Sci 2017; 130:779-790. [PMID: 28062850 DOI: 10.1242/jcs.184838] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 12/29/2016] [Indexed: 01/18/2023] Open
Abstract
In adherent cells, the relevance of a physical mechanotransduction pathway provided by the perinuclear actin cap stress fibers has recently emerged. Here, we investigate the impact of a functional actin cap on the cellular adaptive response to topographical cues and uniaxial cyclic strain. Lmna-deficient fibroblasts are used as a model system because they do not develop an intact actin cap, but predominantly form a basal layer of actin stress fibers underneath the nucleus. We observe that topographical cues induce alignment in both normal and Lmna-deficient fibroblasts, suggesting that the topographical signal transmission occurs independently of the integrity of the actin cap. By contrast, in response to cyclic uniaxial strain, Lmna-deficient cells show a compromised strain avoidance response, which is completely abolished when topographical cues and uniaxial strain are applied along the same direction. These findings point to the importance of an intact and functional actin cap in mediating cellular strain avoidance.
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Affiliation(s)
- Chiara Tamiello
- Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, Eindhoven 5600 MB, The Netherlands
| | - Maurice Halder
- Department of Molecular Cell Biology, CARIM School for Cardiovascular Diseases, Maastricht University, P.O. Box 616, Maastricht 6200 MD, The Netherlands
| | - Miriam A F Kamps
- Department of Molecular Cell Biology, GROW - School for Oncology & Developmental Biology, Maastricht University, P.O. Box 616, Maastricht 6200 MD, The Netherlands
| | - Frank P T Baaijens
- Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, Eindhoven 5600 MB, The Netherlands.,Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, Eindhoven 5600 MB, The Netherlands
| | - Jos L V Broers
- Department of Molecular Cell Biology, CARIM School for Cardiovascular Diseases, Maastricht University, P.O. Box 616, Maastricht 6200 MD, The Netherlands
| | - Carlijn V C Bouten
- Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, Eindhoven 5600 MB, The Netherlands
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38
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Okimura C, Iwadate Y. Hybrid mechanosensing system to generate the polarity needed for migration in fish keratocytes. Cell Adh Migr 2016; 10:406-18. [PMID: 27124267 DOI: 10.1080/19336918.2016.1170268] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Crawling cells can generate polarity for migration in response to forces applied from the substratum. Such reaction varies according to cell type: there are both fast- and slow-crawling cells. In response to periodic stretching of the elastic substratum, the intracellular stress fibers in slow-crawling cells, such as fibroblasts, rearrange themselves perpendicular to the direction of stretching, with the result that the shape of the cells extends in that direction; whereas fast-crawling cells, such as neutrophil-like differentiated HL-60 cells and Dictyostelium cells, which have no stress fibers, migrate perpendicular to the stretching direction. Fish epidermal keratocytes are another type of fast-crawling cell. However, they have stress fibers in the cell body, which gives them a typical slow-crawling cell structure. In response to periodic stretching of the elastic substratum, intact keratocytes rearrange their stress fibers perpendicular to the direction of stretching in the same way as fibroblasts and migrate parallel to the stretching direction, while blebbistatin-treated stress fiber-less keratocytes migrate perpendicular to the stretching direction, in the same way as seen in HL-60 cells and Dictyostelium cells. Our results indicate that keratocytes have a hybrid mechanosensing system that comprises elements of both fast- and slow-crawling cells, to generate the polarity needed for migration.
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Affiliation(s)
- Chika Okimura
- a Faculty of Science , Yamaguchi University , Yamaguchi , Japan
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39
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Okimura C, Ueda K, Sakumura Y, Iwadate Y. Fast-crawling cell types migrate to avoid the direction of periodic substratum stretching. Cell Adh Migr 2016; 10:331-41. [PMID: 26980079 DOI: 10.1080/19336918.2015.1129482] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
To investigate the relationship between mechanical stimuli from substrata and related cell functions, one of the most useful techniques is the application of mechanical stimuli via periodic stretching of elastic substrata. In response to this stimulus, Dictyostelium discoideum cells migrate in a direction perpendicular to the stretching direction. The origins of directional migration, higher migration velocity in the direction perpendicular to the stretching direction or the higher probability of a switch of migration direction to perpendicular to the stretching direction, however, remain unknown. In this study, we applied periodic stretching stimuli to neutrophil-like differentiated HL-60 cells, which migrate perpendicular to the direction of stretch. Detailed analysis of the trajectories of HL-60 cells and Dictyostelium cells obtained in a previous study revealed that the higher probability of a switch of migration direction to that perpendicular to the direction of stretching was the main cause of such directional migration. This directional migration appears to be a strategy adopted by fast-crawling cells in which they do not migrate faster in the direction they want to go, but migrate to avoid a direction they do not want to go.
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Affiliation(s)
- Chika Okimura
- a Faculty of Science , Yamaguchi University , Yamaguchi , Japan
| | - Kazuki Ueda
- a Faculty of Science , Yamaguchi University , Yamaguchi , Japan
| | - Yuichi Sakumura
- b School of Information Science and Technology , Aichi Prefectural University , Aichi , Japan.,c Graduate School of Biological Sciences , Nara Institute of Science and Technology , Nara , Japan
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40
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Aydin O, Aksoy B, Akalin OB, Bayraktar H, Alaca BE. Time-resolved local strain tracking microscopy for cell mechanics. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:023905. [PMID: 26931864 DOI: 10.1063/1.4941715] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A uniaxial cell stretching technique to measure time-resolved local substrate strain while simultaneously imaging adherent cells is presented. The experimental setup comprises a uniaxial stretcher platform compatible with inverted microscopy and transparent elastomer samples with embedded fluorescent beads. This integration enables the acquisition of real-time spatiotemporal data, which is then processed using a single-particle tracking algorithm to track the positions of fluorescent beads for the subsequent computation of local strain. The present local strain tracking method is demonstrated using polydimethylsiloxane (PDMS) samples of rectangular and dogbone geometries. The comparison of experimental results and finite element simulations for the two sample geometries illustrates the capability of the present system to accurately quantify local deformation even when the strain distribution is non-uniform over the sample. For a regular dogbone sample, the experimentally obtained value of local strain at the center of the sample is 77%, while the average strain calculated using the applied cross-head displacement is 48%. This observation indicates that considerable errors may arise when cross-head measurement is utilized to estimate strain in the case of non-uniform sample geometry. Finally, the compatibility of the proposed platform with biological samples is tested using a unibody PDMS sample with a well to contain cells and culture media. HeLa S3 cells are plated on collagen-coated samples and cell adhesion and proliferation are observed. Samples with adherent cells are then stretched to demonstrate simultaneous cell imaging and tracking of embedded fluorescent beads.
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Affiliation(s)
- O Aydin
- Department of Mechanical Engineering, Koç University, Rumelifeneri Yolu, Sariyer 34450 Istanbul, Turkey
| | - B Aksoy
- Department of Mechanical Engineering, Koç University, Rumelifeneri Yolu, Sariyer 34450 Istanbul, Turkey
| | - O B Akalin
- Biomedical Science and Engineering, Koç University, Rumelifeneri Yolu, Sariyer 34450 Istanbul, Turkey
| | - H Bayraktar
- Biomedical Science and Engineering, Koç University, Rumelifeneri Yolu, Sariyer 34450 Istanbul, Turkey
| | - B E Alaca
- Department of Mechanical Engineering, Koç University, Rumelifeneri Yolu, Sariyer 34450 Istanbul, Turkey
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41
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Pakravan HA, Saidi MS, Firoozabadi B. A mechanical model for morphological response of endothelial cells under combined wall shear stress and cyclic stretch loadings. Biomech Model Mechanobiol 2016; 15:1229-43. [PMID: 26769119 DOI: 10.1007/s10237-015-0756-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 12/22/2015] [Indexed: 12/17/2022]
Abstract
The shape and morphology of endothelial cells (ECs) lining the blood vessels are a good indicator for atheroprone and atheroprotected sites. ECs of blood vessels experience both wall shear stress (WSS) and cyclic stretch (CS). These mechanical stimuli influence the shape and morphology of ECs. A few models have been proposed for predicting the morphology of ECs under WSS or CS. In the present study, a mathematical cell population model is developed to simulate the morphology of ECs under combined WSS and CS conditions. The model considers the cytoskeletal filaments, cell-cell interactions, and cell-extracellular matrix interactions. In addition, the reorientation and polymerization of microfilaments are implemented in the model. The simulations are performed for different conditions: without mechanical stimuli, under pure WSS, under pure CS, and under combined WSS and CS. The results are represented as shape and morphology of ECs, shape index, and angle of orientation. The model is validated qualitatively and quantitatively with several experimental studies, and good agreement with experimental studies is achieved. To the best of our knowledge, it is the first model for predicting the morphology of ECs under combined WSS and CS condition. The model can be used to indicate the atheroprone regions of a patient's artery.
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Affiliation(s)
- H A Pakravan
- Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran
| | - M S Saidi
- Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran.
| | - B Firoozabadi
- Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran
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Heading in the Right Direction: Understanding Cellular Orientation Responses to Complex Biophysical Environments. Cell Mol Bioeng 2015; 9:12-37. [PMID: 26900408 PMCID: PMC4746215 DOI: 10.1007/s12195-015-0422-7] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 10/10/2015] [Indexed: 01/09/2023] Open
Abstract
The aim of cardiovascular regeneration is to mimic the biological and mechanical functioning of tissues. For this it is crucial to recapitulate the in vivo cellular organization, which is the result of controlled cellular orientation. Cellular orientation response stems from the interaction between the cell and its complex biophysical environment. Environmental
biophysical cues are continuously detected and transduced to the nucleus through entwined mechanotransduction pathways. Next to the biochemical cascades invoked by the mechanical stimuli, the structural mechanotransduction pathway made of focal adhesions and the actin cytoskeleton can quickly transduce the biophysical signals directly to the nucleus. Observations linking cellular orientation response to biophysical cues have pointed out that the anisotropy and cyclic straining of the substrate influence cellular orientation. Yet, little is known about the mechanisms governing cellular orientation responses in case of cues applied separately and in combination. This review provides the state-of-the-art knowledge on the structural mechanotransduction pathway of adhesive cells, followed by an overview of the current understanding of cellular orientation responses to substrate anisotropy and uniaxial cyclic strain. Finally, we argue that comprehensive understanding of cellular orientation in complex biophysical environments requires systematic approaches based on the dissection of (sub)cellular responses to the individual cues composing the biophysical niche.
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Single cell active force generation under dynamic loading - Part I: AFM experiments. Acta Biomater 2015; 27:236-250. [PMID: 26360596 DOI: 10.1016/j.actbio.2015.09.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 08/14/2015] [Accepted: 09/06/2015] [Indexed: 12/27/2022]
Abstract
A novel series of experiments are performed on single cells using a bespoke AFM system where the response of cells to dynamic loading at physiologically relevant frequencies is uncovered. Measured forces for the untreated cells are dramatically different to cytochalasin-D (cyto-D) treated cells, indicating that the contractile actin cytoskeleton plays a critical role in the response of cells to dynamic loading. Following a change in applied strain magnitude, while maintaining a constant applied strain rate, the compression force for contractile cells recovers to 88.9±7.8% of the steady state force. In contrast, cyto-D cell compression forces recover to only 38.0±6.7% of the steady state force. Additionally, untreated cells exhibit strongly negative (pulling) forces during unloading half-cycles when the probe is retracted. In comparison, negligible pulling forces are measured for cyto-D cells during probe retraction. The current study demonstrates that active contractile forces, generated by actin-myosin cross-bridge cycling, dominate the response of single cells to dynamic loading. Such active force generation is shown to be independent of applied strain magnitude. Passive forces generated by the applied deformation are shown to be of secondary importance, exhibiting a high dependence on applied strain magnitude, in contrast to the active forces in untreated cells. STATEMENT OF SIGNIFICANCE A novel series of experiments are performed on single cells using a bespoke AFM system where the response of cells to dynamic loading at physiologically relevant frequencies is uncovered. Contractile cells, which contain the active force generation machinery of the actin cytoskeleton, are shown to be insensitive to applied strain magnitude, exhibiting high resistance to dynamic compression and stretching. Such trends are not observed for cells in which the actin cytoskeleton has been chemically disrupted. These biomechanical insights have not been previously reported. This detailed characterisation of single cell active and passive stress during dynamic loading has important implications for tissue engineering strategies, where applied deformation has been reported to significantly affect cell mechanotransduction and matrix synthesis.
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Sears C, Kaunas R. The many ways adherent cells respond to applied stretch. J Biomech 2015; 49:1347-1354. [PMID: 26515245 DOI: 10.1016/j.jbiomech.2015.10.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 10/05/2015] [Accepted: 10/10/2015] [Indexed: 10/24/2022]
Abstract
Cells in various tissues are subjected to mechanical stress and strain that have profound effects on cell architecture and function. The specific response of the cell to applied strain depends on multiple factors, including cell contractility, spatial and temporal strain pattern, and substrate dimensionality and rigidity. Recent work has demonstrated that the cell response to applied strain depends on a complex combination of these factors, but the way these factors interact to elicit a specific response is not intuitive. We submit that an understanding of the integrated response of a cell to these factors will provide new insight into mechanobiology and contribute to the effective design of deformable engineered scaffolds meant to provide appropriate mechanical cues to the resident cells.
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Affiliation(s)
- Candice Sears
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843-3120, USA
| | - Roland Kaunas
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843-3120, USA.
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PAKRAVAN HOSSEINALI, SAIDI MOHAMMADSAID, FIROOZABADI BAHAR. FSI SIMULATION OF A HEALTHY CORONARY BIFURCATION FOR STUDYING THE MECHANICAL STIMULI OF ENDOTHELIAL CELLS UNDER DIFFERENT PHYSIOLOGICAL CONDITIONS. J MECH MED BIOL 2015. [DOI: 10.1142/s021951941550089x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Atherosclerosis is a world-spread and well-known disease. This disease strongly relates to the endothelial cells (ECs) function. Normally, the endothelial cells align in the flow direction in the atheroprotected sites; however, in the case of atheroprone sites these cells orient randomly. The mechanical stimuli such as wall shear stress and strains could determine the morphology and function of the endothelial cells. In the present study, we numerically simulated the left main coronary artery (LCA) and its branches to left anterior descending (LAD) and left circumflex coronary (LCX) artery using fluid–structure interaction (FSI) modeling. The results were presented as longitudinal and circumferential strains of ECs as well as wall shear stress. Wide ranges of heart rate, cardiac motion, systolic and diastolic pressures were considered and their effects on mechanical stimuli were described in detail. The results showed that these factors could greatly influence the risk of atherosclerosis and the location of atherosclerotic lesions.
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Affiliation(s)
- HOSSEIN ALI PAKRAVAN
- Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran
| | - MOHAMMAD SAID SAIDI
- Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran
| | - BAHAR FIROOZABADI
- Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran
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Abiko H, Fujiwara S, Ohashi K, Hiatari R, Mashiko T, Sakamoto N, Sato M, Mizuno K. Rho guanine nucleotide exchange factors involved in cyclic-stretch-induced reorientation of vascular endothelial cells. J Cell Sci 2015; 128:1683-95. [PMID: 25795300 DOI: 10.1242/jcs.157503] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 03/13/2015] [Indexed: 12/31/2022] Open
Abstract
Cyclic stretch is an artificial model of mechanical force loading, which induces the reorientation of vascular endothelial cells and their stress fibers in a direction perpendicular to the stretch axis. Rho family GTPases are crucial for cyclic-stretch-induced endothelial cell reorientation; however, the mechanism underlying stretch-induced activation of Rho family GTPases is unknown. A screen of short hairpin RNAs targeting 63 Rho guanine nucleotide exchange factors (Rho-GEFs) revealed that at least 11 Rho-GEFs – Abr, alsin, ARHGEF10, Bcr, GEF-H1 (also known as ARHGEF2), LARG (also known as ARHGEF12), p190RhoGEF (also known as ARHGEF28), PLEKHG1, P-REX2, Solo (also known as ARHGEF40) and α-PIX (also known as ARHGEF6) – which specifically or broadly target RhoA, Rac1 and/or Cdc42, are involved in cyclic-stretch-induced perpendicular reorientation of endothelial cells. Overexpression of Solo induced RhoA activation and F-actin accumulation at cell-cell and cell-substrate adhesion sites. Knockdown of Solo suppressed cyclic-stretch- or tensile-force-induced RhoA activation. Moreover, knockdown of Solo significantly reduced cyclic-stretch-induced perpendicular reorientation of endothelial cells when cells were cultured at high density, but not when they were cultured at low density or pretreated with EGTA or VE-cadherin-targeting small interfering RNAs. These results suggest that Solo is involved in cell-cell-adhesion-mediated mechanical signal transduction during cyclic-stretch-induced endothelial cell reorientation.
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Affiliation(s)
- Hiyori Abiko
- Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Sachiko Fujiwara
- Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Kazumasa Ohashi
- Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Ryuichi Hiatari
- Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Toshiya Mashiko
- Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Naoya Sakamoto
- Department of Biomedical Engineering, Graduate School of Biomedical Engineering, Tohoku University, Sendai, Miyagi 980-8579, Japan
| | - Masaaki Sato
- Department of Biomedical Engineering, Graduate School of Biomedical Engineering, Tohoku University, Sendai, Miyagi 980-8579, Japan
| | - Kensaku Mizuno
- Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
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Haase K, Pelling AE. Investigating cell mechanics with atomic force microscopy. J R Soc Interface 2015; 12:20140970. [PMID: 25589563 PMCID: PMC4345470 DOI: 10.1098/rsif.2014.0970] [Citation(s) in RCA: 216] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 12/18/2014] [Indexed: 12/12/2022] Open
Abstract
Transmission of mechanical force is crucial for normal cell development and functioning. However, the process of mechanotransduction cannot be studied in isolation from cell mechanics. Thus, in order to understand how cells 'feel', we must first understand how they deform and recover from physical perturbations. Owing to its versatility, atomic force microscopy (AFM) has become a popular tool to study intrinsic cellular mechanical properties. Used to directly manipulate and examine whole and subcellular reactions, AFM allows for top-down and reconstitutive approaches to mechanical characterization. These studies show that the responses of cells and their components are complex, and largely depend on the magnitude and time scale of loading. In this review, we generally describe the mechanotransductive process through discussion of well-known mechanosensors. We then focus on discussion of recent examples where AFM is used to specifically probe the elastic and inelastic responses of single cells undergoing deformation. We present a brief overview of classical and current models often used to characterize observed cellular phenomena in response to force. Both simple mechanistic models and complex nonlinear models have been used to describe the observed cellular behaviours, however a unifying description of cell mechanics has not yet been resolved.
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Affiliation(s)
- Kristina Haase
- Department of Physics, Centre for Interdisciplinary NanoPhysics, MacDonald Hall, University of Ottawa, 150 Louis Pasteur, Ottawa, Ontario, Canada
| | - Andrew E Pelling
- Department of Physics, Centre for Interdisciplinary NanoPhysics, MacDonald Hall, University of Ottawa, 150 Louis Pasteur, Ottawa, Ontario, Canada Department of Biology, Gendron Hall, 30 Marie Curie, University of Ottawa, Ottawa, Ontario, Canada Institute for Science Society and Policy, Desmarais Building, 55 Laurier Ave. East, University of Ottawa, Ottawa, Ontario, Canada K1N 6N5
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Greiner AM, Biela SA, Chen H, Spatz JP, Kemkemer R. Temporal responses of human endothelial and smooth muscle cells exposed to uniaxial cyclic tensile strain. Exp Biol Med (Maywood) 2015; 240:1298-309. [PMID: 25687334 DOI: 10.1177/1535370215570191] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 12/05/2014] [Indexed: 01/23/2023] Open
Abstract
The physiology of vascular cells depends on stimulating mechanical forces caused by pulsatile flow. Thus, mechano-transduction processes and responses of primary human endothelial cells (ECs) and smooth muscle cells (SMCs) have been studied to reveal cell-type specific differences which may contribute to vascular tissue integrity. Here, we investigate the dynamic reorientation response of ECs and SMCs cultured on elastic membranes over a range of stretch frequencies from 0.01 to 1 Hz. ECs and SMCs show different cell shape adaptation responses (reorientation) dependent on the frequency. ECs reveal a specific threshold frequency (0.01 Hz) below which no responses is detectable while the threshold frequency for SMCs could not be determined and is speculated to be above 1 Hz. Interestingly, the reorganization of the actin cytoskeleton and focal adhesions system, as well as changes in the focal adhesion area, can be observed for both cell types and is dependent on the frequency. RhoA and Rac1 activities are increased for ECs but not for SMCs upon application of a uniaxial cyclic tensile strain. Analysis of membrane protrusions revealed that the spatial protrusion activity of ECs and SMCs is independent of the application of a uniaxial cyclic tensile strain of 1 Hz while the total number of protrusions is increased for ECs only. Our study indicates differences in the reorientation response and the reaction times of the two cell types in dependence of the stretching frequency, with matching data for actin cytoskeleton, focal adhesion realignment, RhoA/Rac1 activities, and membrane protrusion activity. These are promising results which may allow cell-type specific activation of vascular cells by frequency-selective mechanical stretching. This specific activation of different vascular cell types might be helpful in improving strategies in regenerative medicine.
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Affiliation(s)
- Alexandra M Greiner
- Department of Cell- and Neurobiology, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany
| | - Sarah A Biela
- Department of New Materials and Biosystems, Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Hao Chen
- Department of Cell- and Neurobiology, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany
| | - Joachim P Spatz
- Department of New Materials and Biosystems, Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany Department of Biophysical Chemistry, University of Heidelberg, 69120 Heidelberg, Germany
| | - Ralf Kemkemer
- Department of New Materials and Biosystems, Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany Department of Applied Chemistry, Reutlingen University, 72762 Reutlingen, Germany
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49
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Huang L, Helmke BP. Polarized actin structural dynamics in response to cyclic uniaxial stretch. Cell Mol Bioeng 2014; 8:160-177. [PMID: 25821527 DOI: 10.1007/s12195-014-0370-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Endothelial cell (EC) alignment to directional flow or stretch supports anti-inflammatory functions, but mechanisms controlling polarized structural adaptation in response to physical cues remain unclear. This study aimed to determine whether factors associated with early actin edge ruffling implicated in cell polarization are prerequisite for stress fiber (SF) reorientation in response to cyclic uniaxial stretch. Time-lapse analysis of EGFP-actin in confluent ECs showed that onset of either cyclic uniaxial or equibiaxial stretch caused a non-directional increase in edge ruffling. Edge activity was concentrated in a direction perpendicular to the stretch axis after 60 min, consistent with the direction of SF alignment. Rho-kinase inhibition caused reorientation of both stretch-induced edge ruffling and SF alignment parallel to the stretch axis. Arp2/3 inhibition attenuated stretch-induced cell elongation and disrupted polarized edge dynamics and microtubule organizing center reorientation, but it had no effect on the extent of SF reorientation. Disrupting localization of p21-activated kinase (PAK) did not prevent stretch-induced SF reorientation, suggesting that this Rac effector is not critical in regulating stretch-induced cytoskeletal remodeling. Overall, these results suggest that directional edge ruffling is not a primary mechanism that guides SF reorientation in response to stretch; the two events are coincident but not causal.
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Affiliation(s)
- Lawrence Huang
- Department of Biomedical Engineering, University of Virginia, P. O. Box 800759, Charlottesville, Virginia 22908
| | - Brian P Helmke
- Department of Biomedical Engineering, University of Virginia, P. O. Box 800759, Charlottesville, Virginia 22908 ; Robert M. Berne Cardiovascular Research Center, University of Virginia, P. O. Box 800759, Charlottesville, Virginia 22908
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50
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Janoštiak R, Pataki AC, Brábek J, Rösel D. Mechanosensors in integrin signaling: The emerging role of p130Cas. Eur J Cell Biol 2014; 93:445-54. [DOI: 10.1016/j.ejcb.2014.07.002] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 06/11/2014] [Accepted: 07/01/2014] [Indexed: 12/17/2022] Open
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