51
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Cartagena-Rivera AX, Van Itallie CM, Anderson JM, Chadwick RS. Apical surface supracellular mechanical properties in polarized epithelium using noninvasive acoustic force spectroscopy. Nat Commun 2017; 8:1030. [PMID: 29044161 PMCID: PMC5715111 DOI: 10.1038/s41467-017-01145-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 08/18/2017] [Indexed: 11/24/2022] Open
Abstract
Maintenance of epithelial tissue integrity requires coordination between cell–cell adherens junctions, tight junctions (TJ), and the perijunctional actomyosin cytoskeleton. Here we addressed the hypothesis that alterations in TJ structure and remodeling of the actomyosin cytoskeleton modify epithelial mechanics. Current methods to measure supracellular mechanical properties disrupt intact monolayers, therefore, we developed a novel method using noncontact acoustic frequency-modulation atomic force microscopy (FM-AFM) and tested it on MDCK polarized monolayers. Our results show that double knockdown (dKD) of ZO-1/ZO-2 elevates the apical epithelial tension and effective viscosity. Interestingly, epithelial tension is more sensitive to inhibition of myosin II ATPase activity than to inhibition of ROCK activity, but viscosity is highly sensitive to both. Additionally, we showed epithelial intercellular pulling forces at tricellular junctions and adhesion forces in dKD cells are elevated with an increase in contractility. In conclusion, FM-AFM enables the physiological and quantitative investigation of mechanics in intact epithelium. Determination of apical tension, fluidity, and intercellular adhesive forces in an epithelial monolayer are currently disruptive. Here the authors present a method using acoustic force microscopy to measure changes in these parameters upon tight junction structural alterations in a MDCK monolayer.
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Affiliation(s)
- Alexander X Cartagena-Rivera
- Section on Auditory Mechanics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Christina M Van Itallie
- Laboratory of Tight Junction Structure and Function, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - James M Anderson
- Laboratory of Tight Junction Structure and Function, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Richard S Chadwick
- Section on Auditory Mechanics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA.
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52
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Clathrin-Independent Endocytosis Suppresses Cancer Cell Blebbing and Invasion. Cell Rep 2017; 20:1893-1905. [DOI: 10.1016/j.celrep.2017.08.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 06/15/2017] [Accepted: 07/28/2017] [Indexed: 01/09/2023] Open
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53
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Brückner BR, Nöding H, Janshoff A. Viscoelastic Properties of Confluent MDCK II Cells Obtained from Force Cycle Experiments. Biophys J 2017; 112:724-735. [PMID: 28256232 PMCID: PMC5340129 DOI: 10.1016/j.bpj.2016.12.032] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 12/01/2016] [Accepted: 12/15/2016] [Indexed: 01/04/2023] Open
Abstract
The local mechanical properties of cells are frequently probed by force indentation experiments carried out with an atomic force microscope. Application of common contact models provides a single parameter, the Young’s modulus, to describe the elastic properties of cells. The viscoelastic response of cells, however, is generally measured in separate microrheological experiments that provide complex shear moduli as a function of time or frequency. Here, we present a straightforward way to obtain rheological properties of cells from regular force distance curves collected in typical force indentation measurements. The method allows us to record the stress-strain relationship as well as changes in the weak power law of the viscoelastic moduli. We derive an analytical function based on the elastic-viscoelastic correspondence principle applied to Hertzian contact mechanics to model both indentation and retraction curves. Rheological properties are described by standard viscoelastic models and the paradigmatic weak power law found to interpret the viscoelastic properties of living cells best. We compare our method with atomic force microscopy-based active oscillatory microrheology and show that the method to determine the power law coefficient is robust against drift and largely independent of the indentation depth and indenter geometry. Cells were subject to Cytochalasin D treatment to provoke a drastic change in the power law coefficient and to demonstrate the feasibility of the approach to capture rheological changes extremely fast and precisely. The method is easily adaptable to different indenter geometries and acquires viscoelastic data with high spatiotemporal resolution.
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Affiliation(s)
| | - Helen Nöding
- Georg-August-Universität Göttingen, Institute of Physical Chemistry, Göttingen, Germany
| | - Andreas Janshoff
- Georg-August-Universität Göttingen, Institute of Physical Chemistry, Göttingen, Germany.
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54
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Peña-Oyarzun D, Troncoso R, Kretschmar C, Hernando C, Budini M, Morselli E, Lavandero S, Criollo A. Hyperosmotic stress stimulates autophagy via polycystin-2. Oncotarget 2017; 8:55984-55997. [PMID: 28915568 PMCID: PMC5593539 DOI: 10.18632/oncotarget.18995] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 06/21/2017] [Indexed: 12/13/2022] Open
Abstract
Various intracellular mechanisms are activated in response to stress, leading to adaptation or death. Autophagy, an intracellular process that promotes lysosomal degradation of proteins, is an adaptive response to several types of stress. Osmotic stress occurs under both physiological and pathological conditions, provoking mechanical stress and activating various osmoadaptive mechanisms. Polycystin-2 (PC2), a membrane protein of the polycystin family, is a mechanical sensor capable of activating the cell signaling pathways required for cell adaptation and survival. Here we show that hyperosmotic stress provoked by treatment with hyperosmolar concentrations of sorbitol or mannitol induces autophagy in HeLa and HCT116 cell lines. In addition, we show that mTOR and AMPK, two stress sensor proteins involved modulating autophagy, are downregulated and upregulated, respectively, when cells are subjected to hyperosmotic stress. Finally, our findings show that PC2 is required to promote hyperosmotic stress-induced autophagy. Downregulation of PC2 prevents inhibition of hyperosmotic stress-induced mTOR pathway activation. In conclusion, our data provide new insight into the role of PC2 as a mechanosensor that modulates autophagy under hyperosmotic stress conditions.
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Affiliation(s)
- Daniel Peña-Oyarzun
- Advanced Center for Chronic Diseases, Facultad Ciencias Quimicas y Farmaceuticas & Facultad Medicina, Universidad de Chile, Santiago, Chile.,Center for Molecular Studies of the Cell, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Rodrigo Troncoso
- Advanced Center for Chronic Diseases, Facultad Ciencias Quimicas y Farmaceuticas & Facultad Medicina, Universidad de Chile, Santiago, Chile.,Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile, Santiago, Chile
| | - Catalina Kretschmar
- Advanced Center for Chronic Diseases, Facultad Ciencias Quimicas y Farmaceuticas & Facultad Medicina, Universidad de Chile, Santiago, Chile.,Instituto de Investigación en Ciencias Odontológicas, Facultad de Odontología, Universidad de Chile, Santiago, Chile
| | - Cecilia Hernando
- Advanced Center for Chronic Diseases, Facultad Ciencias Quimicas y Farmaceuticas & Facultad Medicina, Universidad de Chile, Santiago, Chile.,Instituto de Investigación en Ciencias Odontológicas, Facultad de Odontología, Universidad de Chile, Santiago, Chile
| | - Mauricio Budini
- Instituto de Investigación en Ciencias Odontológicas, Facultad de Odontología, Universidad de Chile, Santiago, Chile
| | - Eugenia Morselli
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Sergio Lavandero
- Advanced Center for Chronic Diseases, Facultad Ciencias Quimicas y Farmaceuticas & Facultad Medicina, Universidad de Chile, Santiago, Chile.,Center for Molecular Studies of the Cell, Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Department of Internal Medicine (Cardiology Division), University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Alfredo Criollo
- Advanced Center for Chronic Diseases, Facultad Ciencias Quimicas y Farmaceuticas & Facultad Medicina, Universidad de Chile, Santiago, Chile.,Instituto de Investigación en Ciencias Odontológicas, Facultad de Odontología, Universidad de Chile, Santiago, Chile
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55
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Malinverno C, Corallino S, Giavazzi F, Bergert M, Li Q, Leoni M, Disanza A, Frittoli E, Oldani A, Martini E, Lendenmann T, Deflorian G, Beznoussenko GV, Poulikakos D, Haur ONGK, Uroz M, Trepat X, Parazzoli D, Maiuri P, Yu W, Ferrari A, Cerbino R, Scita G. Endocytic reawakening of motility in jammed epithelia. NATURE MATERIALS 2017; 16:587-596. [PMID: 28135264 PMCID: PMC5407454 DOI: 10.1038/nmat4848] [Citation(s) in RCA: 150] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 12/15/2016] [Indexed: 05/05/2023]
Abstract
Dynamics of epithelial monolayers has recently been interpreted in terms of a jamming or rigidity transition. How cells control such phase transitions is, however, unknown. Here we show that RAB5A, a key endocytic protein, is sufficient to induce large-scale, coordinated motility over tens of cells, and ballistic motion in otherwise kinetically arrested monolayers. This is linked to increased traction forces and to the extension of cell protrusions, which align with local velocity. Molecularly, impairing endocytosis, macropinocytosis or increasing fluid efflux abrogates RAB5A-induced collective motility. A simple model based on mechanical junctional tension and an active cell reorientation mechanism for the velocity of self-propelled cells identifies regimes of monolayer dynamics that explain endocytic reawakening of locomotion in terms of a combination of large-scale directed migration and local unjamming. These changes in multicellular dynamics enable collectives to migrate under physical constraints and may be exploited by tumours for interstitial dissemination.
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Affiliation(s)
- Chiara Malinverno
- IFOM-FIRC Institute of Molecular Oncology, Via Adamello, 16 20139, Milan, Italy
| | - Salvatore Corallino
- IFOM-FIRC Institute of Molecular Oncology, Via Adamello, 16 20139, Milan, Italy
| | - Fabio Giavazzi
- Università degli Studi di Milano, Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, I-20090, Segrate, Italy
- Corresponding authors: , or , or , or
| | - Martin Bergert
- ETH Zurich, Laboratory of Thermodynamics in Emerging Technologies Sonneggstrasse 3,8092 Zurich, Switzerland
| | - Qingsen Li
- IFOM-FIRC Institute of Molecular Oncology, Via Adamello, 16 20139, Milan, Italy
| | - Marco Leoni
- Institut Curie, 26 rue d'Ulm 75248 PARIS CEDEX 05 - France
| | - Andrea Disanza
- IFOM-FIRC Institute of Molecular Oncology, Via Adamello, 16 20139, Milan, Italy
| | - Emanuela Frittoli
- IFOM-FIRC Institute of Molecular Oncology, Via Adamello, 16 20139, Milan, Italy
| | - Amanda Oldani
- IFOM-FIRC Institute of Molecular Oncology, Via Adamello, 16 20139, Milan, Italy
| | - Emanuele Martini
- IFOM-FIRC Institute of Molecular Oncology, Via Adamello, 16 20139, Milan, Italy
| | - Tobias Lendenmann
- ETH Zurich, Laboratory of Thermodynamics in Emerging Technologies Sonneggstrasse 3,8092 Zurich, Switzerland
| | - Gianluca Deflorian
- IFOM-FIRC Institute of Molecular Oncology, Via Adamello, 16 20139, Milan, Italy
| | | | - Dimos Poulikakos
- ETH Zurich, Laboratory of Thermodynamics in Emerging Technologies Sonneggstrasse 3,8092 Zurich, Switzerland
| | - ONG Kok Haur
- Institute of Molecular and Cell Biology (IMCB), A(∗)STAR, Singapore 138673, Singapore
| | - Marina Uroz
- Institute for Bioengineering of Catalonia, Barcelona, Barcelona, 08028 Spain; Catalan Institution for Research and Advanced Studies (ICREA), 08010, Barcelona, Spain; CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), 28029 Madrid, Spain; Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
| | - Xavier Trepat
- Institute for Bioengineering of Catalonia, Barcelona, Barcelona, 08028 Spain; Catalan Institution for Research and Advanced Studies (ICREA), 08010, Barcelona, Spain; CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), 28029 Madrid, Spain; Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
| | - Dario Parazzoli
- IFOM-FIRC Institute of Molecular Oncology, Via Adamello, 16 20139, Milan, Italy
| | - Paolo Maiuri
- IFOM-FIRC Institute of Molecular Oncology, Via Adamello, 16 20139, Milan, Italy
| | - Weimiao Yu
- Institute of Molecular and Cell Biology (IMCB), A(∗)STAR, Singapore 138673, Singapore
| | - Aldo Ferrari
- ETH Zurich, Laboratory of Thermodynamics in Emerging Technologies Sonneggstrasse 3,8092 Zurich, Switzerland
- Corresponding authors: , or , or , or
| | - Roberto Cerbino
- Università degli Studi di Milano, Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, I-20090, Segrate, Italy
- Corresponding authors: , or , or , or
| | - Giorgio Scita
- IFOM-FIRC Institute of Molecular Oncology, Via Adamello, 16 20139, Milan, Italy
- Università degli Studi di Milano, Dipartimento di Oncologia e Emato-Oncologia , I-20133, Milan, Italy
- Corresponding authors: , or , or , or
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56
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Haase K, Shendruk TN, Pelling AE. Rapid dynamics of cell-shape recovery in response to local deformations. SOFT MATTER 2017; 13:567-577. [PMID: 27942684 DOI: 10.1039/c6sm02560a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
It is vital that cells respond rapidly to mechanical cues within their microenvironment through changes in cell shape and volume, which rely upon the mechanical properties of cells' highly interconnected cytoskeletal networks and intracellular fluid redistributions. While previous research has largely investigated deformation mechanics, we now focus on the immediate cell-shape recovery response following mechanical perturbation by inducing large, local, and reproducible cellular deformations using AFM. By continuous imaging within the plane of deformation, we characterize the membrane and cortical response of HeLa cells to unloading, and model the recovery via overdamped viscoelastic dynamics. Importantly, the majority (90%) of HeLa cells recover their cell shape in <1 s. Despite actin remodelling on this time scale, we show that cell-shape recovery time is not affected by load duration, nor magnitude for untreated cells. To further explore this rapid recovery response, we expose cells to cytoskeletal destabilizers and osmotic shock conditions, which uncovers the interplay between actin and osmotic pressure. We show that the rapid dynamics of recovery depend crucially on intracellular pressure, and provide strong evidence that cortical actin is the key regulator in the cell-shape recovery processes, in both cancerous and non-cancerous epithelial cells.
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Affiliation(s)
- Kristina Haase
- Department of Physics, University of Ottawa, MacDonald Hall, 150 Louis Pasteur, Canada.
| | - Tyler N Shendruk
- The Rudolf Peierls Centre for Theoretical Physics, Department of Physics, University of Oxford, 1 Keble Road, Oxford, OX1 3NP, UK
| | - Andrew E Pelling
- Department of Physics, University of Ottawa, MacDonald Hall, 150 Louis Pasteur, Canada. and Department of Biology, University of Ottawa, Gendron Hall, 30 Marie Curie, Canada and Institute for Science, Society and Policy, University of Ottawa, Simard Hall, 60 University, Ottawa, ON K1N 6N5, Canada and SymbioticA, School of Anatomy, Physiology and Human Biology, University of Western Australia, Perth WA 6009, Australia
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57
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Li N, Sharifi-Mood N, Tu F, Lee D, Radhakrishnan R, Baumgart T, Stebe KJ. Curvature-Driven Migration of Colloids on Tense Lipid Bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:600-610. [PMID: 28036186 PMCID: PMC5706785 DOI: 10.1021/acs.langmuir.6b03406] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Inspired by proteins that generate membrane curvature, sense the underlying membrane geometry, and migrate driven by curvature gradients, we explore the question: Can colloids, adhered to lipid bilayers, also sense and respond to membrane geometry? We report the migration of Janus microparticles adhered to giant unilamellar vesicles elongated to present spatially varying curvatures. In our experiments, colloids migrate only when the membranes are tense, suggesting that they migrate to minimize membrane area. By determining the energy dissipated along a trajectory, the energy field is inferred to depend on the local deviatoric curvature, like curvature driven capillary migration on interfaces between immiscible fluids. In this latter system, energy gradients are larger, so colloids move deterministically, whereas the paths traced by colloids on vesicles have significant fluctuations. By addressing the role of Brownian motion, we show that the observed migration is analogous to curvature driven capillary migration, with membrane tension playing the role of interfacial tension. Since this motion is mediated by membrane shape, it can be turned on and off by dynamically deforming the vesicle. While particle-particle interactions on lipid membranes have been considered in many contributions, we report here an exciting and previously unexplored modality to actively direct the migration of colloids to desired locations on lipid bilayers.
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Affiliation(s)
- N. Li
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, 220 South 33rd Street, 311A Towne Building, Philadelphia, PA 19104, USA
| | - N. Sharifi-Mood
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, 220 South 33rd Street, 311A Towne Building, Philadelphia, PA 19104, USA
| | - F. Tu
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, 220 South 33rd Street, 311A Towne Building, Philadelphia, PA 19104, USA
| | - D. Lee
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, 220 South 33rd Street, 311A Towne Building, Philadelphia, PA 19104, USA
| | - R. Radhakrishnan
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, 220 South 33rd Street, 311A Towne Building, Philadelphia, PA 19104, USA
- Department of Bioengineering, University of Pennsylvania, 210 S. 33rd St., 240 Skirkanich Hall, Philadelphia, PA 19104, USA
| | - T. Baumgart
- Department of Chemistry, University of Pennsylvania, 231 S. 34 Street, Philadelphia, PA 19104, USA
| | - K. J. Stebe
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, 220 South 33rd Street, 311A Towne Building, Philadelphia, PA 19104, USA
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58
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Nriagu J, Darroudi F, Shomar B. Health effects of desalinated water: Role of electrolyte disturbance in cancer development. ENVIRONMENTAL RESEARCH 2016; 150:191-204. [PMID: 27295409 DOI: 10.1016/j.envres.2016.05.038] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Revised: 05/18/2016] [Accepted: 05/20/2016] [Indexed: 06/06/2023]
Abstract
This review contends that "healthy" water in terms of electrolyte balance is as important as "pure" water in promoting public health. It considers the growing use of desalination (demineralization) technologies in drinking water treatment which often results in tap water with very low concentrations of sodium, potassium, magnesium and calcium. Ingestion of such water can lead to electrolyte abnormalities marked by hyponatremia, hypokalemia, hypomagnesemia and hypocalcemia which are among the most common and recognizable features in cancer patients. The causal relationships between exposure to demineralized water and malignancies are poorly understood. This review highlights some of the epidemiological and in vivo evidence that link dysregulated electrolyte metabolism with carcinogenesis and the development of cancer hallmarks. It discusses how ingestion of demineralized water can have a procarcinogenic effect through mediating some of the critical pathways and processes in the cancer microenvironment such as angiogenesis, genomic instability, resistance to programmed cell death, sustained proliferative signaling, cell immortalization and tumorigenic inflammation. Evidence that hypoosmotic stress-response processes can upregulate a number of potential oncogenes is well supported by a number studies. In view of the rising production and consumption of demineralized water in most parts of the world, there is a strong need for further research on the biological importance and protean roles of electrolyte abnormalities in promoting, antagonizing or otherwise enabling the development of cancer. The countries of the Gulf Cooperative Council (GCC) where most people consume desalinated water would be a logical place to start this research.
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Affiliation(s)
- Jerome Nriagu
- Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, MI 48109, United States.
| | - Firouz Darroudi
- Centre of Human Safety and Environmental Research, Department of Health Sciences, College of North Atlantic, Doha, Qatar; Centre of Human Safety & Health and Diagnostic Genome Analysis, Red Crescent Hospital, Dubai, United Arab Emirates
| | - Basem Shomar
- Qatar Environmental and Energy Research Institute (QEERI), Qatar Foundation, Doha, Qatar
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59
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Byun S, Hecht VC, Manalis SR. Characterizing Cellular Biophysical Responses to Stress by Relating Density, Deformability, and Size. Biophys J 2016; 109:1565-73. [PMID: 26488647 DOI: 10.1016/j.bpj.2015.08.038] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 07/23/2015] [Accepted: 08/24/2015] [Indexed: 01/28/2023] Open
Abstract
Cellular physical properties are important indicators of specific cell states. Although changes in individual biophysical parameters, such as cell size, density, and deformability, during cellular processes have been investigated in great detail, relatively little is known about how they are related. Here, we use a suspended microchannel resonator (SMR) to measure single-cell density, volume, and passage time through a narrow constriction of populations of cells subjected to a variety of environmental stresses. Osmotic stress significantly affects density and volume, as previously shown. In contrast to density and volume, the effect of an osmotic challenge on passage time is relatively small. Deformability, as determined by comparing passage times for cells with similar volume, exhibits a strong dependence on osmolarity, indicating that passage time alone does not always provide a meaningful proxy for deformability. Finally, we find that protein synthesis inhibition, cell-cycle arrest, protein kinase inhibition, and cytoskeletal disruption result in unexpected relationships among deformability, density, and volume. Taken together, our results suggest that by measuring multiple biophysical parameters, one can detect unique characteristics that more specifically reflect cellular behaviors.
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Affiliation(s)
- Sangwon Byun
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts; Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Vivian C Hecht
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Scott R Manalis
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts; Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts; Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts.
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60
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López-Ortega O, Ovalle-García E, Ortega-Blake I, Antillón A, Chávez-Munguía B, Patiño-López G, Fragoso-Soriano R, Santos-Argumedo L. Myo1g is an active player in maintaining cell stiffness in B-lymphocytes. Cytoskeleton (Hoboken) 2016; 73:258-68. [DOI: 10.1002/cm.21299] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 04/11/2016] [Accepted: 04/13/2016] [Indexed: 12/11/2022]
Affiliation(s)
- O. López-Ortega
- Departamento De Biomedicina Molecular; Centro De Investigación Y De Estudios Avanzados Del Instituto Politécnico Nacional; Ciudad De México C. P. 07360 México
- Facultad De Medicina, Universidad Nacional Autónoma De México; Ciudad De México C. P. 04510 México
| | - E. Ovalle-García
- Universidad Autónoma De Nuevo León, UANL. Facultad De Ingeniería Mecánica Y Eléctrica, Av. Universidad S/N, Ciudad Universitaria, San Nicolás De Los Garza; Nuevo León C. P. 66451 México
| | - I. Ortega-Blake
- Instituto De Ciencias Físicas, UNAM; Cuernavaca Morelos C. P. 62210 México
| | - A. Antillón
- Instituto De Ciencias Físicas, UNAM; Cuernavaca Morelos C. P. 62210 México
| | - B. Chávez-Munguía
- Departamento De Infectómica Y Patogénesis Molecular; Centro De Investigación Y De Estudios Avanzados Del Instituto Politécnico Nacional; Ciudad De México C. P. 07360 México
| | - G. Patiño-López
- Laboratorio De Investigación En Inmunología Y Proteómica, Hospital Infantil De México, “Federico Gómez”; Ciudad De México C. P. 06720 México
| | - R. Fragoso-Soriano
- Departamento De Física; Centro De Investigación Y De Estudios Avanzados Del Instituto Politécnico Nacional; Ciudad De México C. P. 07360 México
| | - L. Santos-Argumedo
- Departamento De Biomedicina Molecular; Centro De Investigación Y De Estudios Avanzados Del Instituto Politécnico Nacional; Ciudad De México C. P. 07360 México
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61
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Jia Z, Ikeda R, Ling J, Viatchenko-Karpinski V, Gu JG. Regulation of Piezo2 Mechanotransduction by Static Plasma Membrane Tension in Primary Afferent Neurons. J Biol Chem 2016; 291:9087-104. [PMID: 26929410 DOI: 10.1074/jbc.m115.692384] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Indexed: 11/06/2022] Open
Abstract
The Piezo2 channel is a newly identified mammalian mechanical transducer that confers rapidly adapting mechanically activated (RA-MA) currents in primary afferent neurons. The Piezo2 channels sense rapid membrane displacement, but it is not clear whether they are sensitive to osmotic swelling, which slowly increases static plasma membrane tension (SPMT). Here, we show that SPMT exerts a profound impact on the mechanical sensitivity of RA-MA channels in primary afferent neurons. RA-MA currents are greatly enhanced, and the mechanical threshold was reduced in both primary afferent neurons of rat dorsal root ganglia (DRG) and HEK293 cells heterologously expressing Piezo2 when these cells undergo osmotic swelling to increase SPMT. Osmotic swelling switches the kinetics of RA-MA currents to the slowly adapting type in both cultured DRG neurons and HEK293 cells heterologously expressing Piezo2. The potentiation of RA-MA currents is abolished when cultured DRG neurons are treated with cytochalasin D, an actin filament disruptor that prevents SPMT of cultured DRG neurons from an increase by osmotic swelling. Osmotic swelling significantly increases DRG neuron mechano-excitability such that a subthreshold mechanical stimulus can result in action potential firing. Behaviorally, the mechanical hind paw withdrawal threshold in rats is reduced following the injection of a hypotonic solution, but this osmotic effect is abolished when cytochalasin D or Gd(3+) is co-administered with the hypo-osmotic solution. Taken together, our findings suggest that Piezo2-mediated mechanotransduction is regulated by SPMT in primary afferent neurons. Because SPMT can be changed by multiple biological factors, our findings may have broad implications in mechanical sensitivity under physiological and pathological conditions.
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Affiliation(s)
- Zhanfeng Jia
- the Department of Anesthesiology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267-0531, the Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei Province 050017, China, and
| | - Ryo Ikeda
- the Department of Anesthesiology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267-0531, the Department of Orthopedic Surgery, Jikei University School of Medicine, 3-25-8 Nishi-Shinbashi, Minato-ku, Tokyo 105-8461, Japan
| | - Jennifer Ling
- the Department of Anesthesiology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267-0531, From the Department of Anesthesiology and Perioperative Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Viacheslav Viatchenko-Karpinski
- From the Department of Anesthesiology and Perioperative Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Jianguo G Gu
- the Department of Anesthesiology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267-0531, From the Department of Anesthesiology and Perioperative Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294,
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Shan Y, Wang H. The structure and function of cell membranes examined by atomic force microscopy and single-molecule force spectroscopy. Chem Soc Rev 2016; 44:3617-38. [PMID: 25893228 DOI: 10.1039/c4cs00508b] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The cell membrane is one of the most complicated biological complexes, and long-term fierce debates regarding the cell membrane persist because of technical hurdles. With the rapid development of nanotechnology and single-molecule techniques, our understanding of cell membranes has substantially increased. Atomic force microscopy (AFM) has provided several unprecedented advances (e.g., high resolution, three-dimensional and in situ measurements) in the study of cell membranes and has been used to systematically dissect the membrane structure in situ from both sides of membranes; as a result, novel models of cell membranes have recently been proposed. This review summarizes the new progress regarding membrane structure using in situ AFM and single-molecule force spectroscopy (SMFS), which may shed light on the study of the structure and functions of cell membranes.
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Affiliation(s)
- Yuping Shan
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, P. R. China.
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63
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Ezrin is a Major Regulator of Membrane Tension in Epithelial Cells. Sci Rep 2015; 5:14700. [PMID: 26435322 PMCID: PMC4592969 DOI: 10.1038/srep14700] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2015] [Accepted: 09/07/2015] [Indexed: 11/12/2022] Open
Abstract
Plasma membrane tension is responsible for a variety of cellular functions such as motility, cell division, and endocytosis. Since membrane tension is dominated by the attachment of the actin cortex to the inner leaflet of the plasma membrane, we investigated the importance of ezrin, a major cross-linker of the membrane-cytoskeleton interface, for cellular mechanics of confluent MDCK II cells. For this purpose, we carried out ezrin depletion experiments and also enhanced the number of active ezrin molecules at the interface. Mechanical properties were assessed by force indentation experiments followed by membrane tether extraction. PIP2 micelles were injected into individual living cells to reinforce the linkage between plasma membrane and actin-cortex, while weakening of this connection was reached by ezrin siRNA and administration of the inhibitors neomycin and NSC 668394, respectively. We observed substantial stiffening of cells and an increase in membrane tension after addition of PIP2 micelles. In contrast, reduction of active ezrin led to a decrease of membrane tension accompanied by loss of excess surface area, increase in cortical tension, remodelling of actin cytoskeleton, and reduction of cell height. The data confirm the importance of the ezrin-mediated connection between plasma membrane and cortex for cellular mechanics and cell morphology.
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64
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Membrane tension and membrane fusion. Curr Opin Struct Biol 2015; 33:61-7. [PMID: 26282924 DOI: 10.1016/j.sbi.2015.07.010] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2015] [Revised: 07/19/2015] [Accepted: 07/24/2015] [Indexed: 12/29/2022]
Abstract
Diverse cell biological processes that involve shaping and remodeling of cell membranes are regulated by membrane lateral tension. Here we focus on the role of tension in driving membrane fusion. We discuss the physics of membrane tension, forces that can generate the tension in plasma membrane of a cell, and the hypothesis that tension powers expansion of membrane fusion pores in late stages of cell-to-cell and exocytotic fusion. We propose that fusion pore expansion can require unusually large membrane tensions or, alternatively, low line tensions of the pore resulting from accumulation in the pore rim of membrane-bending proteins. Increase of the inter-membrane distance facilitates the reaction.
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65
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Zwiewka M, Nodzyński T, Robert S, Vanneste S, Friml J. Osmotic Stress Modulates the Balance between Exocytosis and Clathrin-Mediated Endocytosis in Arabidopsis thaliana. MOLECULAR PLANT 2015; 8:1175-87. [PMID: 25795554 DOI: 10.1016/j.molp.2015.03.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 03/04/2015] [Accepted: 03/05/2015] [Indexed: 05/18/2023]
Abstract
The sessile life style of plants creates the need to deal with an often adverse environment, in which water availability can change on a daily basis, challenging the cellular physiology and integrity. Changes in osmotic conditions disrupt the equilibrium of the plasma membrane: hypoosmotic conditions increase and hyperosmotic environment decrease the cell volume. Here, we show that short-term extracellular osmotic treatments are closely followed by a shift in the balance between endocytosis and exocytosis in root meristem cells. Acute hyperosmotic treatments (ionic and nonionic) enhance clathrin-mediated endocytosis simultaneously attenuating exocytosis, whereas hypoosmotic treatments have the opposite effects. In addition to clathrin recruitment to the plasma membrane, components of early endocytic trafficking are essential during hyperosmotic stress responses. Consequently, growth of seedlings defective in elements of clathrin or early endocytic machinery is more sensitive to hyperosmotic treatments. We also found that the endocytotic response to a change of osmotic status in the environment is dominant over the presumably evolutionary more recent regulatory effect of plant hormones, such as auxin. These results imply that osmotic perturbation influences the balance between endocytosis and exocytosis acting through clathrin-mediated endocytosis. We propose that tension on the plasma membrane determines the addition or removal of membranes at the cell surface, thus preserving cell integrity.
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Affiliation(s)
- Marta Zwiewka
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 5, CZ-625 00 Brno, Czech Republic; Department of Plant Systems Biology, VIB and Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, 9052 Gent, Belgium
| | - Tomasz Nodzyński
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 5, CZ-625 00 Brno, Czech Republic; Department of Plant Systems Biology, VIB and Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, 9052 Gent, Belgium
| | - Stéphanie Robert
- Department of Plant Systems Biology, VIB and Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, 9052 Gent, Belgium
| | - Steffen Vanneste
- Department of Plant Systems Biology, VIB and Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, 9052 Gent, Belgium
| | - Jiří Friml
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 5, CZ-625 00 Brno, Czech Republic; Department of Plant Systems Biology, VIB and Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, 9052 Gent, Belgium; Institute of Science and Technology (IST) Austria, Am Campus 1, 3400 Klosterneuburg, Austria.
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66
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Elastic properties of epithelial cells probed by atomic force microscopy. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:3075-82. [PMID: 26193077 DOI: 10.1016/j.bbamcr.2015.07.010] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 06/30/2015] [Accepted: 07/10/2015] [Indexed: 12/21/2022]
Abstract
Cellular mechanics plays a crucial role in many biological processes such as cell migration, cell growth, embryogenesis, and oncogenesis. Epithelia respond to environmental cues comprising biochemical and physical stimuli through defined changes in cell elasticity. For instance, cells can differentiate between certain properties such as viscoelasticity or topography of substrates by adapting their own elasticity and shape. A living cell is a complex viscoelastic body that not only exhibits a shell architecture composed of a membrane attached to a cytoskeleton cortex but also generates contractile forces through its actomyosin network. Here we review cellular mechanics of single cells in the context of epithelial cell layers responding to chemical and physical stimuli. This article is part of a Special Issue entitled: Mechanobiology.
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67
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Schäfer E, Vache M, Kliesch TT, Janshoff A. Mechanical response of adherent giant liposomes to indentation with a conical AFM-tip. SOFT MATTER 2015; 11:4487-95. [PMID: 25946988 DOI: 10.1039/c5sm00191a] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Indentation of giant liposomes with a conical indenter is described by means of a tension-based membrane model. We found that nonlinear membrane theory neglecting the impact of bending sufficiently describes the mechanical response of liposomes to indentation as measured by atomic force microscopy. Giant vesicles are gently adsorbed on glassy surfaces via avidin-biotin linkages and indented centrally using an atomic force microscope equipped with conventional sharp tips mounted on top of an inverted microscope. Force indentation curves display a nonlinear response that allows to extract pre-stress of the bilayer T0 and the area compressibility modulus KA by computing the contour of the vesicle at a given force. The values for KA of fluid membranes correspond well to what is known from micropipet suction experiments and inferred from membrane undulation monitoring. Assembly of actin shells inside the liposome considerably stiffens the vesicles resulting in significantly larger area compressibility modules. The analysis can be easily extended to different indenter geometries with rotational symmetry.
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Affiliation(s)
- Edith Schäfer
- Department of Chemistry, University of Goettingen, Goettingen, Germany.
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68
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Mullen CA, Vaughan TJ, Voisin MC, Brennan MA, Layrolle P, McNamara LM. Cell morphology and focal adhesion location alters internal cell stress. J R Soc Interface 2014; 11:20140885. [PMID: 25297316 PMCID: PMC4223909 DOI: 10.1098/rsif.2014.0885] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2014] [Accepted: 09/15/2014] [Indexed: 12/30/2022] Open
Abstract
Extracellular mechanical cues have been shown to have a profound effect on osteogenic cell behaviour. However, it is not known precisely how these cues alter intracellular mechanics to initiate changes in cell behaviour. In this study, a combination of in vitro culture of MC3T3-E1 cells and finite-element modelling was used to investigate the effects of passive differences in substrate stiffness on intracellular mechanics. Cells on collagen-based substrates were classified based on the presence of cell processes and the dimensions of various cellular features were quantified. Focal adhesion (FA) density was quantified from immunohistochemical staining, while cell and substrate stiffnesses were measured using a live-cell atomic force microscope. Computational models of cell morphologies were developed using an applied contraction of the cell body to simulate active cell contraction. The results showed that FA density is directly related to cell morphology, while the effect of substrate stiffness on internal cell tension was modulated by both cell morphology and FA density, as investigated by varying the number of adhesion sites present in each morphological model. We propose that the cells desire to achieve a homeostatic stress state may play a role in osteogenic cell differentiation in response to extracellular mechanical cues.
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Affiliation(s)
- C A Mullen
- Centre for Biomechanics Research (BMEC), Department of Biomedical Engineering, NUI Galway, Galway, Republic of Ireland National Centre for Biomedical Engineering Science (NCBES), NUI Galway, Galway, Republic of Ireland
| | - T J Vaughan
- Centre for Biomechanics Research (BMEC), Department of Biomedical Engineering, NUI Galway, Galway, Republic of Ireland
| | - M C Voisin
- Centre for Biomechanics Research (BMEC), Department of Biomedical Engineering, NUI Galway, Galway, Republic of Ireland National Centre for Biomedical Engineering Science (NCBES), NUI Galway, Galway, Republic of Ireland
| | - M A Brennan
- INSERM UMR957, Laboratory of the Pathophysiology of Bone Resorption, Faculty of Medicine, University of Nantes, Nantes, France
| | - P Layrolle
- INSERM UMR957, Laboratory of the Pathophysiology of Bone Resorption, Faculty of Medicine, University of Nantes, Nantes, France
| | - L M McNamara
- Centre for Biomechanics Research (BMEC), Department of Biomedical Engineering, NUI Galway, Galway, Republic of Ireland National Centre for Biomedical Engineering Science (NCBES), NUI Galway, Galway, Republic of Ireland
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69
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Abstract
Glycosphingolipids are important structural constituents of cellular membranes. They are involved in the formation of nanodomains ("lipid rafts"), which serve as important signaling platforms. Invasive bacterial pathogens exploit these signaling domains to trigger actin polymerization for the bending of the plasma membrane and the engulfment of the bacterium--a key process in bacterial uptake. However, it is unknown whether glycosphingolipids directly take part in the membrane invagination process. Here, we demonstrate that a "lipid zipper," which is formed by the interaction between the bacterial surface lectin LecA and its cellular receptor, the glycosphingolipid Gb3, triggers plasma membrane bending during host cell invasion of the bacterium Pseudomonas aeruginosa. In vitro experiments with Gb3-containing giant unilamellar vesicles revealed that LecA/Gb3-mediated lipid zippering was sufficient to achieve complete membrane engulfment of the bacterium. In addition, theoretical modeling elucidated that the adhesion energy of the LecA-Gb3 interaction is adequate to drive the engulfment process. In cellulo experiments demonstrated that inhibition of the LecA/Gb3 lipid zipper by either lecA knockout, Gb3 depletion, or application of soluble sugars that interfere with LecA binding to Gb3 significantly lowered P. aeruginosa uptake by host cells. Of note, membrane engulfment of P. aeruginosa occurred independently of actin polymerization, thus corroborating that lipid zippering alone is sufficient for this crucial first step of bacterial host-cell entry. Our study sheds new light on the impact of glycosphingolipids in the cellular invasion of bacterial pathogens and provides a mechanistic explication of the initial uptake processes.
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70
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Kuhlmann JW, Mey IP, Steinem C. Modulating the lateral tension of solvent-free pore-spanning membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:8186-8192. [PMID: 24950370 DOI: 10.1021/la5019086] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The plasma membrane of animal cells is attached to the cytoskeleton, which significantly contributes to the lateral tension of the membrane. Lateral membrane tension has been shown to be an important physical regulator of cellular processes such as cell motility and morphology as well as exo- and endocytosis. Here, we report on lipid bilayers spanning highly ordered pore arrays, where we can control the lateral membrane tension by chemically varying the surface functionalization of the porous substrate. Surface functionalization was achieved by a gold coating on top of the pore rims of the hexagonal array of pores in silicon nitride substrates with pore radii of 600 nm followed by subsequent incubation with various n-propanolic mixtures of 6-mercapto-1-hexanol (6MH) and O-cholesteryl N-(8'-mercapto-3',6'-dioxaoctyl)carbamate (CPEO3). Pore-spanning membranes composed of 1,2-diphytanoyl-sn-glycero-3-phosphocholine were prepared by spreading giant unilamellar vesicles on these functionalized porous silicon nitride substrates. Different mixtures of 6MH and CPEO3 provided self-assembled monolayers (SAMs) with different compositions as analyzed by contact angle and PM-IRRAS measurements. Site specific force-indentation experiments on the pore-spanning membranes attached to the different SAMs revealed a clear dependence of the amount of CPEO3 in the monolayer on the lateral membrane tension. While bilayers on pure 6MH monolayers show an average lateral membrane tension of 1.4 mN m(-1), a mixed monolayer of CPEO3 and 6MH obtained from a solution with 9.1 mol % CPEO3 exhibits a lateral tension of 5.0 mN m(-1). From contact angle and PM-IRRAS results, the mole fraction of CPEO3 in solution can be roughly translated into a CPEO3 surface concentration of 40 mol %. Our results clearly demonstrate that the free energy difference between the supported and freestanding part of the membrane depends on the chemical composition of the SAM, which controls the lateral membrane tension.
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Affiliation(s)
- Jan W Kuhlmann
- Institute of Organic and Biomolecular Chemistry, University of Göttingen , Tammannstraße 2, 37077 Göttingen, Germany
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71
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Shvets E, Ludwig A, Nichols BJ. News from the caves: update on the structure and function of caveolae. Curr Opin Cell Biol 2014; 29:99-106. [PMID: 24908346 DOI: 10.1016/j.ceb.2014.04.011] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 04/03/2014] [Accepted: 04/24/2014] [Indexed: 10/25/2022]
Abstract
Recent data from the study of the cell biology of caveolae have provided insights both into how these flask-shaped invaginations of the plasma membrane are formed and how they may function in different contexts. This review discusses experiments that analyse the composition and ultrastructural distribution of protein complexes responsible for generating caveolae, that suggest functions for caveolae in response to mechanical stress or damage to the plasma membrane, that show that caveolae may have an important role during the signalling events for regulation of metabolism, and that imply that caveolae can act as endocytic vesicles at the plasma membrane. We also highlight unexpected roles for caveolar proteins in regulating circadian rhythms and new insights into the way in which caveolae may be involved in fatty acid uptake in the intestine. Current outstanding questions in the field are emphasised.
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Affiliation(s)
| | - Alexander Ludwig
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
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72
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Gabella C, Bertseva E, Bottier C, Piacentini N, Bornert A, Jeney S, Forró L, Sbalzarini IF, Meister JJ, Verkhovsky AB. Contact angle at the leading edge controls cell protrusion rate. Curr Biol 2014; 24:1126-32. [PMID: 24794299 DOI: 10.1016/j.cub.2014.03.050] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 02/04/2014] [Accepted: 03/18/2014] [Indexed: 02/02/2023]
Abstract
Plasma membrane tension and the pressure generated by actin polymerization are two antagonistic forces believed to define the protrusion rate at the leading edge of migrating cells [1-5]. Quantitatively, resistance to actin protrusion is a product of membrane tension and mean local curvature (Laplace's law); thus, it depends on the local geometry of the membrane interface. However, the role of the geometry of the leading edge in protrusion control has not been yet investigated. Here, we manipulate both the cell shape and substrate topography in the model system of persistently migrating fish epidermal keratocytes. We find that the protrusion rate does not correlate with membrane tension, but, instead, strongly correlates with cell roundness, and that the leading edge of the cell exhibits pinning on substrate ridges-a phenomenon characteristic of spreading of liquid drops. These results indicate that the leading edge could be considered a triple interface between the substrate, membrane, and extracellular medium and that the contact angle between the membrane and the substrate determines the load on actin polymerization and, therefore, the protrusion rate. Our findings thus illuminate a novel relationship between the 3D shape of the cell and its dynamics, which may have implications for cell migration in 3D environments.
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Affiliation(s)
- Chiara Gabella
- Laboratory of Cell Biophysics, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
| | - Elena Bertseva
- Laboratory of Cell Biophysics, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland; Laboratory of Physics of Complex Matter, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Céline Bottier
- Laboratory of Cell Biophysics, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Niccolò Piacentini
- Laboratory of Cell Biophysics, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Alicia Bornert
- Laboratory of Cell Biophysics, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Sylvia Jeney
- Laboratory of Physics of Complex Matter, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - László Forró
- Laboratory of Physics of Complex Matter, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Ivo F Sbalzarini
- MOSAIC Group, Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Jean-Jacques Meister
- Laboratory of Cell Biophysics, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Alexander B Verkhovsky
- Laboratory of Cell Biophysics, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
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73
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Schneider D, Baronsky T, Pietuch A, Rother J, Oelkers M, Fichtner D, Wedlich D, Janshoff A. Tension monitoring during epithelial-to-mesenchymal transition links the switch of phenotype to expression of moesin and cadherins in NMuMG cells. PLoS One 2013; 8:e80068. [PMID: 24339870 PMCID: PMC3855076 DOI: 10.1371/journal.pone.0080068] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 10/09/2013] [Indexed: 01/06/2023] Open
Abstract
Structural alterations during epithelial-to-mesenchymal transition (EMT) pose a substantial challenge to the mechanical response of cells and are supposed to be key parameters for an increased malignancy during metastasis. Herein, we report that during EMT, apical tension of the epithelial cell line NMuMG is controlled by cell-cell contacts and the architecture of the underlying actin structures reflecting the mechanistic interplay between cellular structure and mechanics. Using force spectroscopy we find that tension in NMuMG cells slightly increases 24 h after EMT induction, whereas upon reaching the final mesenchymal-like state characterized by a complete loss of intercellular junctions and a concerted down-regulation of the adherens junction protein E-cadherin, the overall tension becomes similar to that of solitary adherent cells and fibroblasts. Interestingly, the contribution of the actin cytoskeleton on apical tension increases significantly upon EMT induction, most likely due to the formation of stable and highly contractile stress fibers which dominate the elastic properties of the cells after the transition. The structural alterations lead to the formation of single, highly motile cells rendering apical tension a good indicator for the cellular state during phenotype switching. In summary, our study paves the way towards a more profound understanding of cellular mechanics governing fundamental morphological programs such as the EMT.
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Affiliation(s)
- David Schneider
- Institute of Physical Chemistry, Georg-August-University Göttingen, Göttingen, Germany
| | - Thilo Baronsky
- Institute of Physical Chemistry, Georg-August-University Göttingen, Göttingen, Germany
| | - Anna Pietuch
- Institute of Physical Chemistry, Georg-August-University Göttingen, Göttingen, Germany
| | - Jan Rother
- Institute of Physical Chemistry, Georg-August-University Göttingen, Göttingen, Germany
| | - Marieelen Oelkers
- Institute of Physical Chemistry, Georg-August-University Göttingen, Göttingen, Germany
| | - Dagmar Fichtner
- Institute for Cell and Developmental Biology, Karlsruhe Institute of Technology (KIT), Fritz Haber Weg 2, Karlsruhe, Germany
| | - Doris Wedlich
- Institute for Cell and Developmental Biology, Karlsruhe Institute of Technology (KIT), Fritz Haber Weg 2, Karlsruhe, Germany
| | - Andreas Janshoff
- Institute of Physical Chemistry, Georg-August-University Göttingen, Göttingen, Germany
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74
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Gómez-Martínez R, Hernández-Pinto AM, Duch M, Vázquez P, Zinoviev K, de la Rosa EJ, Esteve J, Suárez T, Plaza JA. Silicon chips detect intracellular pressure changes in living cells. NATURE NANOTECHNOLOGY 2013; 8:517-521. [PMID: 23812188 DOI: 10.1038/nnano.2013.118] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 05/24/2013] [Indexed: 06/02/2023]
Abstract
The ability to measure pressure changes inside different components of a living cell is important, because it offers an alternative way to study fundamental processes that involve cell deformation. Most current techniques such as pipette aspiration, optical interferometry or external pressure probes use either indirect measurement methods or approaches that can damage the cell membrane. Here we show that a silicon chip small enough to be internalized into a living cell can be used to detect pressure changes inside the cell. The chip, which consists of two membranes separated by a vacuum gap to form a Fabry-Pérot resonator, detects pressure changes that can be quantified from the intensity of the reflected light. Using this chip, we show that extracellular hydrostatic pressure is transmitted into HeLa cells and that these cells can endure hypo-osmotic stress without significantly increasing their intracellular hydrostatic pressure.
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Affiliation(s)
- Rodrigo Gómez-Martínez
- Instituto de Microelectrónica de Barcelona, IMB-CNM (CSIC), Esfera UAB, Campus UAB, 08193, Cerdanyola, Barcelona, Spain
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