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Bernard C, Carotenuto AR, Pugno NM, Fraldi M, Deseri L. Modelling lipid rafts formation through chemo-mechanical interplay triggered by receptor-ligand binding. Biomech Model Mechanobiol 2024; 23:485-505. [PMID: 38060155 DOI: 10.1007/s10237-023-01787-2] [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: 07/28/2023] [Accepted: 10/21/2023] [Indexed: 12/08/2023]
Abstract
Cell membranes, mediator of many biological mechanisms from adhesion and metabolism up to mutation and infection, are highly dynamic and heterogeneous environments exhibiting a strong coupling between biochemical events and structural re-organisation. This involves conformational changes induced, at lower scales, by lipid order transitions and by the micro-mechanical interplay of lipids with transmembrane proteins and molecular diffusion. Particular attention is focused on lipid rafts, ordered lipid microdomains rich of signalling proteins, that co-localise to enhance substance trafficking and activate different intracellular biochemical pathways. In this framework, the theoretical modelling of the dynamic clustering of lipid rafts implies a full multiphysics coupling between the kinetics of phase changes and the mechanical work performed by transmembrane proteins on lipids, involving the bilayer elasticity. This mechanism produces complex interspecific dynamics in which membrane stresses and chemical potentials do compete by determining different morphological arrangements, alteration in diffusive walkways and coalescence phenomena, with a consequent influence on both signalling potential and intracellular processes. Therefore, after identifying the leading chemo-mechanical interactions, the present work investigates from a modelling perspective the spatio-temporal evolution of raft domains to theoretically explain co-localisation and synergy between proteins' activation and raft formation, by coupling diffusive and mechanical phenomena to observe different morphological patterns and clustering of ordered lipids. This could help to gain new insights into the remodelling of cell membranes and could potentially suggest mechanically based strategies to control their selectivity, by orienting intracellular functions and mechanotransduction.
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Affiliation(s)
- Chiara Bernard
- Department of Civil, Environmental and Mechanical Engineering, University of Trento, Trento, Italy
| | - Angelo Rosario Carotenuto
- Department of Structures for Engineering and Architecture, University of Naples "Federico II", Naples, Italy
- Laboratory of Integrated Mechanics and Imaging for Testing and Simulation (LIMITS), University of Naples "Federico II", Naples, Italy
| | - Nicola Maria Pugno
- Department of Civil, Environmental and Mechanical Engineering, University of Trento, Trento, Italy
- Laboratory for Bioinspired, Bionic, Nano, Meta Materials and Mechanics, University of Trento, Trento, Italy
- School of Engineering and Materials Science, Queen Mary University of London, London, UK
| | - Massimiliano Fraldi
- Department of Structures for Engineering and Architecture, University of Naples "Federico II", Naples, Italy
- Laboratory of Integrated Mechanics and Imaging for Testing and Simulation (LIMITS), University of Naples "Federico II", Naples, Italy
- Département de Physique, LPENS, École Normale Supérieure-PSL, Paris, France
| | - Luca Deseri
- Department of Civil, Environmental and Mechanical Engineering, University of Trento, Trento, Italy.
- Department of Mechanical Engineering and Material Sciences, MEMS-SSoE, University of Pittsburgh, Pittsburgh, USA.
- Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, USA.
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, USA.
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2
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do Nascimento Amorim MDS, Silva França ÁR, Santos-Oliveira R, Rodrigues Sanches J, Marinho Melo T, Araújo Serra Pinto B, Barbosa LRS, Alencar LMR. Atomic Force Microscopy Applied to the Study of Tauopathies. ACS Chem Neurosci 2024; 15:699-715. [PMID: 38305187 DOI: 10.1021/acschemneuro.3c00819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2024] Open
Abstract
Atomic force microscopy (AFM) is a scanning probe microscopy technique which has a physical principle, the measurement of interatomic forces between a very thin tip and the surface of a sample, allowing the obtaining of quantitative data at the nanoscale, contributing to the surface study and mechanical characterization. Due to its great versatility, AFM has been used to investigate the structural and nanomechanical properties of several inorganic and biological materials, including neurons affected by tauopathies. Tauopathies are neurodegenerative diseases featured by aggregation of phosphorylated tau protein inside neurons, leading to functional loss and progressive neurotoxicity. In the broad universe of neurodegenerative diseases, tauopathies comprise the most prevalent, with Alzheimer's disease as its main representative. This review highlights the use of AFM as a suitable research technique for the study of cellular damages in tauopathies, even in early stages, allowing elucidation of pathogenic mechanisms of these diseases.
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Affiliation(s)
- Maria do Socorro do Nascimento Amorim
- Laboratory of Biophysics and Nanosystems, Department of Physics, Federal University of Maranhão, Campus Bacanga, São Luís 65080-805, Maranhão, Brazil
| | - Álefe Roger Silva França
- Laboratory of Biophysics and Nanosystems, Department of Physics, Federal University of Maranhão, Campus Bacanga, São Luís 65080-805, Maranhão, Brazil
| | - Ralph Santos-Oliveira
- Nuclear Engineering Institute, Brazilian Nuclear Energy Commission, Rio de Janeiro 21941906, Brazil
- Laboratory of Nanoradiopharmacy, Rio de Janeiro State University, Rio de Janeiro 23070200, Brazil
| | - Jonas Rodrigues Sanches
- Laboratory of Experimental Physiology, Department of Physiological Sciences, Federal University of Maranhão, Campus Bacanga, São Luís, 65080-805, Maranhão, Brazil
| | - Thamys Marinho Melo
- Laboratory of Experimental Physiology, Department of Physiological Sciences, Federal University of Maranhão, Campus Bacanga, São Luís, 65080-805, Maranhão, Brazil
| | - Bruno Araújo Serra Pinto
- Laboratory of Experimental Physiology, Department of Physiological Sciences, Federal University of Maranhão, Campus Bacanga, São Luís, 65080-805, Maranhão, Brazil
| | - Leandro R S Barbosa
- Department of General Physics, Institute of Physics, University of São Paulo, São Paulo 05508-000, SP, Brazil
- Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas 13083-100, SP, Brazil
| | - Luciana Magalhães Rebelo Alencar
- Laboratory of Biophysics and Nanosystems, Department of Physics, Federal University of Maranhão, Campus Bacanga, São Luís 65080-805, Maranhão, Brazil
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3
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Angom RS, Kulkarni T, Wang E, Kumar Dutta S, Bhattacharya S, Das P, Mukhopadhyay D. Vascular Endothelial Growth Factor Receptor-1 Modulates Hypoxia-Mediated Endothelial Senescence and Cellular Membrane Stiffness via YAP-1 Pathways. Front Cell Dev Biol 2022; 10:903047. [PMID: 35846360 PMCID: PMC9283904 DOI: 10.3389/fcell.2022.903047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 06/13/2022] [Indexed: 11/23/2022] Open
Abstract
Hypoxia-induced endothelial cell (EC) dysfunction has been implicated as potential initiators of different pathogenesis, including Alzheimer’s disease and vascular dementia. However, in-depth structural, mechanical, and molecular mechanisms leading to EC dysfunction and pathology need to be revealed. Here, we show that ECs exposed to hypoxic conditions readily enter a senescence phenotype. As expected, hypoxia upregulated the expression of vascular endothelial growth factor (VEGFs) and its receptors (VEGFRs) in the ECs. Interestingly, Knockdown of VEGFR-1 expression prior to hypoxia exposure prevented EC senescence, suggesting an important role of VEGFR-1 expression in the induction of EC senescence. Using atomic force microscopy, we showed that senescent ECs had a flattened cell morphology, decreased membrane ruffling, and increased membrane stiffness, demonstrating unique morphological and nanomechanical signatures. Furthermore, we show that hypoxia inhibited the Hippo pathway Yes-associated protein (YAP-1) expression and knockdown of YAP-1 induced senescence in the ECs, supporting a key role of YAP-1 expression in the induction of EC senescence. And importantly, VEGFR-1 Knockdown in the ECs modulated YAP-1 expression, suggesting a novel VEGFR-1-YAP-1 axis in the induction of hypoxia-mediated EC senescence. In conclusion, VEGFR-1 is overexpressed in ECs undergoing hypoxia-mediated senescence, and the knockdown of VEGFR-1 restores cellular structural and nanomechanical integrity by recovering YAP-1 expression.
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Affiliation(s)
| | - Tanmay Kulkarni
- Department of Biochemistry and Molecular Biology, Jacksonville, FL, United States
| | - Enfeng Wang
- Department of Biochemistry and Molecular Biology, Jacksonville, FL, United States
| | - Shamit Kumar Dutta
- Department of Biochemistry and Molecular Biology, Jacksonville, FL, United States
| | - Santanu Bhattacharya
- Department of Biochemistry and Molecular Biology, Jacksonville, FL, United States
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Jacksonville, FL, United States
| | - Pritam Das
- Department of Biochemistry and Molecular Biology, Jacksonville, FL, United States
| | - Debabrata Mukhopadhyay
- Department of Biochemistry and Molecular Biology, Jacksonville, FL, United States
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Jacksonville, FL, United States
- *Correspondence: Debabrata Mukhopadhyay,
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4
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Avetisov SE, Osipyan GA, Abukerimova AK, Akovantseva AA, Efremov YM, Frolova AA, Kotova SL, Timashev PS. [Experimental studies of the biomechanical properties of the cornea]. Vestn Oftalmol 2022; 138:124-131. [PMID: 35801891 DOI: 10.17116/oftalma2022138031124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The review presents the results of experimental studies of the biomechanical properties of the cornea. Selective evaluation of the individual corneal structures (for example, limiting membranes) using classical mechanical tests is to a certain extent limited due to the rather small thickness of these structures and the related difficulties in sample fixation. In real practice, the use of a method better adapted for conducting such studies - atomic force microscopy (AFM) - remains promising, since on the one hand it eliminates the need for mechanical capture and retention of the sample, and on the other - provides the capability for studying its segments separately.
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Affiliation(s)
- S E Avetisov
- I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
- Research Institute of Eye Diseases, Moscow, Russia
| | - G A Osipyan
- Research Institute of Eye Diseases, Moscow, Russia
| | | | - A A Akovantseva
- Institute of Photonic Technologies of the Crystallography and Photonics Research Center, Moscow, Russia
| | - Yu M Efremov
- Institute of Regenerative Medicine of the I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
| | - A A Frolova
- Digital Biodesign and Personalized Healthcare Center of the I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
| | - S L Kotova
- Institute of Regenerative Medicine of the I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
- N.N. Semenov Federal Research Center for Chemical Physics, Moscow, Russia
| | - P S Timashev
- Institute of Regenerative Medicine of the I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
- Digital Biodesign and Personalized Healthcare Center of the I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
- N.N. Semenov Federal Research Center for Chemical Physics, Moscow, Russia
- Lomonosov Moscow State University, Moscow, Russia
- Institute of Photonic Technologies of the Crystallography and Photonics Research Center, Moscow, Russia
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5
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Alsharif N, Eshaghi B, Reinhard BM, Brown KA. Physiologically Relevant Mechanics of Biodegradable Polyester Nanoparticles. NANO LETTERS 2020; 20:7536-7542. [PMID: 32986433 PMCID: PMC7834348 DOI: 10.1021/acs.nanolett.0c03004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Despite the extensive use of biodegradable polyester nanoparticles for drug delivery, and reports of the strong influence of nanoparticle mechanics on nano-bio interactions, there is a lack of systematic studies on the mechanics of these nanoparticles under physiologically relevant conditions. Here, we report indentation experiments on poly(lactic acid) and poly(lactide-co-glycolide) nanoparticles using atomic force microscopy. While dried nanoparticles were found to be rigid at room temperature, their elastic modulus was found to decrease by as much as 30 fold under simulated physiological conditions (i.e., in water at 37 °C). Differential scanning calorimetry confirms that this softening can be attributed to the glass transition of the nanoparticles. Using a combination of mechanical and thermoanalytical characterization, the plasticizing effects of miniaturization, molecular weight, and immersion in water were investigated. Collectively, these experiments provide insight for experimentalists exploring the relationship between polymer nanoparticle mechanics and in vivo behavior.
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Affiliation(s)
- Nourin Alsharif
- Department of Mechanical Engineering, Boston University, Boston, Massachusetts 02215, United States
| | - Behnaz Eshaghi
- Department of Chemistry and the Photonics Center, Boston University, Boston, Massachusetts, 02215, United States
| | - Björn M. Reinhard
- Department of Chemistry and the Photonics Center, Boston University, Boston, Massachusetts, 02215, United States
| | - Keith A. Brown
- Department of Mechanical Engineering, Boston University, Boston, Massachusetts 02215, United States
- Physics Department and Division of Materials Science and Engineering, Boston University, Boston, Massachusetts 02215, United States
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6
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Applications of atomic force microscopy in immunology. Front Med 2020; 15:43-52. [PMID: 32820379 DOI: 10.1007/s11684-020-0769-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 03/04/2020] [Indexed: 01/20/2023]
Abstract
Cellular mechanics, a major regulating factor of cellular architecture and biological functions, responds to intrinsic stresses and extrinsic forces exerted by other cells and the extracellular matrix in the microenvironment. Cellular mechanics also acts as a fundamental mediator in complicated immune responses, such as cell migration, immune cell activation, and pathogen clearance. The principle of atomic force microscopy (AFM) and its three running modes are introduced for the mechanical characterization of living cells. The peak force tapping mode provides the most delicate and desirable virtues to collect high-resolution images of morphology and force curves. For a concrete description of AFM capabilities, three AFM applications are discussed. These applications include the dynamic progress of a neutrophil-extracellular-trap release by neutrophils, the immunological functions of macrophages, and the membrane pore formation mediated by perforin, streptolysin O, gasdermin D, or membrane attack complex.
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7
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Cosgun ZC, Fels B, Kusche-Vihrog K. Nanomechanics of the Endothelial Glycocalyx. THE AMERICAN JOURNAL OF PATHOLOGY 2020; 190:732-741. [DOI: 10.1016/j.ajpath.2019.07.021] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Revised: 07/10/2019] [Accepted: 07/30/2019] [Indexed: 12/12/2022]
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8
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Recent advances in bioimaging with high-speed atomic force microscopy. Biophys Rev 2020; 12:363-369. [PMID: 32172451 DOI: 10.1007/s12551-020-00670-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 02/26/2020] [Indexed: 01/13/2023] Open
Abstract
Among various microscopic techniques for characterizing protein structures and functions, high-speed atomic force microscopy (HS-AFM) is a unique technique in that it allows direct visualization of structural changes and molecular interactions of proteins without any labeling in a liquid environment. Since the development of the HS-AFM was first reported in 2001, it has been applied to analyze the dynamics of various types of proteins, including motor proteins, membrane proteins, DNA-binding proteins, amyloid proteins, and artificial proteins. This method has now become a versatile tool indispensable for biophysical research. This short review summarizes some bioimaging applications of HS-AFM reported in the last few years and novel applications of HS-AFM utilizing the unique ability of AFM to gain mechanical properties of samples in addition to structural information.
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9
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Andrei L, Kasas S, Ochoa Garrido I, Stanković T, Suárez Korsnes M, Vaclavikova R, Assaraf YG, Pešić M. Advanced technological tools to study multidrug resistance in cancer. Drug Resist Updat 2020; 48:100658. [DOI: 10.1016/j.drup.2019.100658] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 09/26/2019] [Accepted: 09/27/2019] [Indexed: 02/06/2023]
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10
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Rubiano A, Galitz C, Simmons CS. Mechanical Characterization by Mesoscale Indentation: Advantages and Pitfalls for Tissue and Scaffolds. Tissue Eng Part C Methods 2019; 25:619-629. [PMID: 30848168 DOI: 10.1089/ten.tec.2018.0372] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Regenerative medicine and tissue engineering are hindered by the lack of consistent measurements and standards for the mechanical characterization of tissue and scaffolds. Indentation methods for soft matter are favored because of their compatibility with small, arbitrarily shaped samples, but contact mechanics models required to interpret data are often inappropriate for soft, viscous materials. In this study, we demonstrate indentation experiments on a variety of human biopsies, animal tissue, and engineered scaffolds, and we explore the complexities of fitting analytical models to these data. Although objections exist to using Hertz contact models for soft, viscoelastic biological materials since soft matter violates their original assumptions, we demonstrate the experimental conditions that enable consistency and comparability (regardless of arguable misappropriation). Appropriate experimental conditions involving sample hydration, the indentation depth, and the ratio of the probe size to sample thickness enable repeatable metrics that are valuable when comparing synthetic scaffolds and host tissue, and bounds on these parameters are carefully described and discussed. We have also identified a reliable quasistatic parameter that can be derived from indentation data to help researchers compare results across materials and experiments. Although Hertz contact mechanics and linear viscoelastic models may constitute oversimplification for biological materials, the reporting of such simple metrics alongside more complex models is expected to support researchers in tissue engineering and regenerative medicine by providing consistency across efforts to characterize soft matter. Impact Statement To engineer replacement tissue requires a deep understanding of its biomechanical properties. Mesoscale indentation (between micron and millimeter length scales) is well-suited to characterize tissue and engineered replacements as it accommodates small, oddly shaped samples. However, it is easy to run afoul of the assumptions for common contact models when working with biological materials. In this study, we describe experimental procedures and modeling approaches that allow researchers to take advantage of indentation for biomechanical characterization while minimizing its weaknesses.
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Affiliation(s)
- Andrés Rubiano
- Department of Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering, Gainesville, Florida
| | - Carly Galitz
- Department of Mathematics, College of Liberal Arts and Sciences, Gainesville, Florida
| | - Chelsey S Simmons
- Department of Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering, Gainesville, Florida.,J. Crayton Pruitt Family Department of Biomedical Engineering Herbert Wertheim College of Engineering, Gainesville, Florida.,Division of Cardiovascular Medicine, College of Medicine, University of Florida, Gainesville, Florida
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11
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Cárdenas-Pérez S, Chanona-Pérez JJ, Méndez-Méndez JV, Arzate-Vázquez I, Hernández-Varela JD, Vera NG. Recent advances in atomic force microscopy for assessing the nanomechanical properties of food materials. Trends Food Sci Technol 2019. [DOI: 10.1016/j.tifs.2018.04.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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12
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Milani P, Chlasta J, Abdayem R, Kezic S, Haftek M. Changes in nano-mechanical properties of human epidermal cornified cells depending on their proximity to the skin surface. J Mol Recognit 2018; 31:e2722. [DOI: 10.1002/jmr.2722] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 03/14/2018] [Accepted: 04/04/2018] [Indexed: 12/23/2022]
Affiliation(s)
| | | | - Rawad Abdayem
- CNRS UMR5305, Laboratory of Tissue Biology and Therapeutic Engineering (LBTI); Lyon France
- L'Oréal, R&I, Aulnay sous Bois; France
| | - Sanja Kezic
- Coronel Institute of Occupational Health, Amsterdam Public Health Research Institute, Academic Medical Center; University of Amsterdam; Amsterdam The Netherlands
| | - Marek Haftek
- CNRS UMR5305, Laboratory of Tissue Biology and Therapeutic Engineering (LBTI); Lyon France
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13
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Abstract
Imaging of nano-sized particles and sample features is crucial in a variety of research fields. For instance in biological sciences, where it is paramount to investigate structures at the single particle level. Often two-dimensional images are not sufficient and further information such as topography and mechanical properties are required. Furthermore, to increase the biological relevance, it is desired to perform the imaging in close to physiological environments. Atomic force microscopy (AFM) meets these demands in an all-in-one instrument. It provides high-resolution images including surface height information leading to three-dimensional information on sample morphology. AFM can be operated both in air and in buffer solutions. Moreover, it has the capacity to determine protein and membrane material properties via the force spectroscopy mode. Here we discuss the principles of AFM operation and provide examples of how biomolecules can be studied. By including new approaches such as high-speed AFM (HS-AFM) we show how AFM can be used to study a variety of static and dynamic single biomolecules and biomolecular assemblies.
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Affiliation(s)
- Melissa C Piontek
- Moleculaire Biofysica, Zernike Instituut, Rijksuniversiteit Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Wouter H Roos
- Moleculaire Biofysica, Zernike Instituut, Rijksuniversiteit Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands.
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14
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Dinarelli S, Girasole M, Longo G. Methods for Atomic Force Microscopy of Biological and Living Specimens. Methods Mol Biol 2018; 1814:529-539. [PMID: 29956253 DOI: 10.1007/978-1-4939-8591-3_31] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Two main precautions must be taken into account to obtain high-resolution morphological and nanomechanical characterization of biological specimens with an atomic force microscope: the tip-sample interaction and the sample-substrate adhesion. In this chapter we discuss the necessary steps for a correct preparation of three types of biological samples: erythrocytes, bacteria, and osteoblasts. The main goal is to deliver reproducible protocols to produce good cellular adhesion and minimizing the morphological alterations of the specimens.
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Affiliation(s)
- Simone Dinarelli
- Istituto di Struttura della Materia ISM - CNR, Via del Fosso del Cavaliere 100, Rome, Italy
| | - Marco Girasole
- Istituto di Struttura della Materia ISM - CNR, Via del Fosso del Cavaliere 100, Rome, Italy
| | - Giovanni Longo
- Istituto di Struttura della Materia ISM - CNR, Via del Fosso del Cavaliere 100, Rome, Italy.
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15
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Prystopiuk V, Fels B, Simon CS, Liashkovich I, Pasrednik D, Kronlage C, Wedlich-Söldner R, Oberleithner H, Fels J. A two-phase response of endothelial cells to hydrostatic pressure. J Cell Sci 2018; 131:jcs.206920. [DOI: 10.1242/jcs.206920] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 05/10/2018] [Indexed: 01/15/2023] Open
Abstract
The vascular endothelium is exposed to three types of mechanical forces: blood flow-mediated shear stress, vessel-diameter dependent wall tension and hydrostatic pressure. Despite considerable variations of blood pressure in normal and pathological physiology, little is known about the acute molecular and cellular effects of hydrostatic pressure on endothelial cells. Here, we used a combination of quantitative fluorescence microscopy, atomic force microscopy and molecular perturbations to characterize the specific response of endothelial cells to pressure application. We identified a two-phase response of endothelial cells to acute (1 h) vs. chronic (24 h) pressure application (100 mmHg). While both regimes induce cortical stiffening, the acute response is linked to calcium-mediated myosin activation, whereas the chronic cell response is dominated by increased cortical actin density and a loss in endothelial barrier function. GsMTx-4 and amiloride inhibit the acute pressure response, which suggest the sodium channel ENaC as key player in endothelial pressure sensing. The described two-phase pressure response may participate in the differential effects of transient changes in blood pressure and hypertension.
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Affiliation(s)
- Valeria Prystopiuk
- Institute of Physiology II, University of Münster, Robert-Koch-Str. 27b, 48149 Münster, Germany
- Cells-In-Motion Cluster of Excellence (EXC1003-CiM), University of Münster, 48149, Münster, Germany
- current address: Institute of Life Sciences, Université Catholique de Louvain, Croix du Sud, 4-5, bte L7.07.06, Louvain-la-Neuve B-1348, Belgium
| | - Benedikt Fels
- Institute of Physiology II, University of Münster, Robert-Koch-Str. 27b, 48149 Münster, Germany
- Cells-In-Motion Cluster of Excellence (EXC1003-CiM), University of Münster, 48149, Münster, Germany
| | - Caroline Sophie Simon
- Institute of Cell Dynamics and Imaging, University of Münster, Von-Esmarch-Str. 56, 48149 Münster, Germany
- Cells-In-Motion Cluster of Excellence (EXC1003-CiM), University of Münster, 48149, Münster, Germany
| | - Ivan Liashkovich
- Institute of Physiology II, University of Münster, Robert-Koch-Str. 27b, 48149 Münster, Germany
- Cells-In-Motion Cluster of Excellence (EXC1003-CiM), University of Münster, 48149, Münster, Germany
| | - Dzmitry Pasrednik
- Institute of Physiology II, University of Münster, Robert-Koch-Str. 27b, 48149 Münster, Germany
- Cells-In-Motion Cluster of Excellence (EXC1003-CiM), University of Münster, 48149, Münster, Germany
| | - Cornelius Kronlage
- Institute of Physiology II, University of Münster, Robert-Koch-Str. 27b, 48149 Münster, Germany
- Cells-In-Motion Cluster of Excellence (EXC1003-CiM), University of Münster, 48149, Münster, Germany
| | - Roland Wedlich-Söldner
- Institute of Cell Dynamics and Imaging, University of Münster, Von-Esmarch-Str. 56, 48149 Münster, Germany
- Cells-In-Motion Cluster of Excellence (EXC1003-CiM), University of Münster, 48149, Münster, Germany
| | - Hans Oberleithner
- Institute of Physiology II, University of Münster, Robert-Koch-Str. 27b, 48149 Münster, Germany
- Cells-In-Motion Cluster of Excellence (EXC1003-CiM), University of Münster, 48149, Münster, Germany
| | - Johannes Fels
- Institute of Cell Dynamics and Imaging, University of Münster, Von-Esmarch-Str. 56, 48149 Münster, Germany
- Cells-In-Motion Cluster of Excellence (EXC1003-CiM), University of Münster, 48149, Münster, Germany
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16
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Amadeu de Oliveira F, MacVinish LJ, Amin S, Herath D, Jeggle P, Mela I, Pieri M, Sharma C, Jarvis GE, Levy FM, Santesso MR, Khan ZN, Leite AL, Oliveira RC, Buzalaf MAR, Edwardson JM. The effect of fluoride on the structure, function, and proteome of intestinal epithelia. ENVIRONMENTAL TOXICOLOGY 2018; 33:63-71. [PMID: 29068160 DOI: 10.1002/tox.22495] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 10/06/2017] [Accepted: 10/06/2017] [Indexed: 06/07/2023]
Abstract
Fluoride exposure is widespread, with drinking water commonly containing natural and artificially added sources of the ion. Ingested fluoride undergoes absorption across the gastric and intestinal epithelia. Previous studies have reported adverse gastrointestinal effects with high levels of fluoride exposure. Here, we examined the effects of fluoride on the transepithelial ion transport and resistance of three intestinal epithelia. We used the Caco-2 cell line as a model of human intestinal epithelium, and rat and mouse colonic epithelia for purposes of comparison. Fluoride caused a concentration-dependent decline in forskolin-induced Cl- secretion and transepithelial resistance of Caco-2 cell monolayers, with an IC50 for fluoride of about 3 mM for both parameters. In the presence of 5 mM fluoride, transepithelial resistance fell exponentially with time, with a t1/2 of about 7 hours. Subsequent imaging by immunofluorescence and scanning electron microscopy showed structural abnormalities in Caco-2 cell monolayers exposed to fluoride. The Young's modulus of the epithelium was not affected by fluoride, although proteomic analysis revealed changes in expression of a number of proteins, particularly those involved in cell-cell adhesion. In line with its effects on Caco-2 cell monolayers, fluoride, at 5 mM, also had profound effects on Cl- secretion and transepithelial resistance of both rat and mouse colonic epithelia. Our results show that treatment with fluoride has major effects on the structure, function, and proteome of intestinal epithelia, but only at concentrations considerably higher than those likely to be encountered in vivo, when much lower fluoride doses are normally ingested on a chronic basis.
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Affiliation(s)
- Flávia Amadeu de Oliveira
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
- Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, São Paulo, Brazil
| | - Lesley J MacVinish
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Simran Amin
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Duleni Herath
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Pia Jeggle
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Ioanna Mela
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Maria Pieri
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Chetanya Sharma
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Gavin E Jarvis
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Flávia M Levy
- Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, São Paulo, Brazil
| | - Mariana R Santesso
- Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, São Paulo, Brazil
| | - Zohaib N Khan
- Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, São Paulo, Brazil
| | - Aline L Leite
- Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, São Paulo, Brazil
| | - Rodrigo C Oliveira
- Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, São Paulo, Brazil
| | - Marília A R Buzalaf
- Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, São Paulo, Brazil
| | - J Michael Edwardson
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
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17
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A single point mutation in precursor protein VI doubles the mechanical strength of human adenovirus. J Biol Phys 2017; 44:119-132. [PMID: 29243050 PMCID: PMC5928017 DOI: 10.1007/s10867-017-9479-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 11/10/2017] [Indexed: 12/23/2022] Open
Abstract
Viruses are extensively studied as vectors for vaccine applications and gene therapies. For these applications, understanding the material properties of viruses is crucial for creating optimal functionality. Using atomic force microscopy (AFM) nanoindentation, we studied the mechanical properties of human adenovirus type 5 with the fiber of type 35 (Ad5F35) and compared it to viral capsids with a single point mutation in the protein VI precursor protein (pVI-S28C). Surprisingly, the pVI-S28C mutant turned out to be twice as stiff as the Ad5F35 capsids. We suggest that this major increase in strength is the result of the DNA crosslinking activity of precursor protein VII, as this protein was detected in the pVI-S28C mutant capsids. The infectivity was similar for both capsids, indicating that mutation did not affect the ability of protein VI to lyse the endosomal membrane. This study highlights that it is possible to increase the mechanical stability of a capsid even with a single point mutation while not affecting the viral life cycle. Such insight can help enable the development of more stable vectors for therapeutic applications.
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18
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The endothelial αENaC contributes to vascular endothelial function in vivo. PLoS One 2017; 12:e0185319. [PMID: 28950003 PMCID: PMC5614594 DOI: 10.1371/journal.pone.0185319] [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: 03/22/2017] [Accepted: 09/11/2017] [Indexed: 11/19/2022] Open
Abstract
The Epithelial Sodium Channel (ENaC) is a key player in renal sodium homeostasis. The expression of α β γ ENaC subunits has also been described in the endothelium and vascular smooth muscle, suggesting a role in vascular function. We recently demonstrated that endothelial ENaC is involved in aldosterone-modulated endothelial stiffness. Here we explore the functional role of the endothelial αENaC subunit in vascular function in vivo. Compared to littermates, mice with conditional αENaC subunit gene inactivation in the endothelium only (endo-αENaC Knock Out mice) had no difference in their physiological parameters such as systolic blood pressure or heart rate. Acute and long-term renal Na+ handlings were not affected, indicating that endothelial αENaC subunit is not involved in renal sodium balance. Pharmacological inhibition of ENaC with benzamil blunted acetylcholine-induced nitric oxide production in mesenteric arteries from wild type mice but not in endo-αENaC KO mice, suggesting a critical role of endothelial ENaC in agonist-induced nitric oxide production. In endo-αENaC KO mice, compensatory mechanisms occurred and steady state vascular function was not altered except for flow-mediated dilation. Our data suggest that endothelial αENaC contributes to vascular endothelial function in vivo.
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19
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Madsen CD, Cox TR. Relative Stiffness Measurements of Tumour Tissues by Shear Rheology. Bio Protoc 2017; 7:e2265. [PMID: 34541251 DOI: 10.21769/bioprotoc.2265] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Revised: 02/04/2017] [Accepted: 04/05/2017] [Indexed: 12/13/2022] Open
Abstract
The microenvironment of solid tumours is a critical contributor to the progression of tumours and offers a promising target for therapeutic intervention (Cox and Erler, 2011; Barker et al., 2012 ; Cox et al., 2016; Cox and Erler, 2016). The properties of the tumour microenvironment vary significantly from that of the original tissue in both biochemistry and biomechanics. At present, the complex interplay between the biomechanical properties of the microenvironment and tumour cell phenotype is under intense investigation. The ability to measure the biomechanical properties of tumour samples from cancer models will increase our understanding of their importance in solid tumour biology. Here we report a simple method to measure the viscoelastic properties of tumour specimens using a controlled strain rotational rheometer.
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Affiliation(s)
- Chris D Madsen
- Department of Laboratory Medicine, Division of Translational Cancer Research, Lund University, Lund, Sweden
| | - Thomas R Cox
- The Garvan Institute of Medical Research and The Kinghorn Cancer Centre, Cancer Division, St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Australia
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20
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Schierke F, Wyrwoll MJ, Wisdorf M, Niedzielski L, Maase M, Ruck T, Meuth SG, Kusche-Vihrog K. Nanomechanics of the endothelial glycocalyx contribute to Na +-induced vascular inflammation. Sci Rep 2017; 7:46476. [PMID: 28406245 PMCID: PMC5390251 DOI: 10.1038/srep46476] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 03/20/2017] [Indexed: 12/11/2022] Open
Abstract
High dietary salt (NaCl) is a known risk factor for cardiovascular pathologies and inflammation. High plasma Na+ concentrations (high Na+) have been shown to stiffen the endothelial cortex and decrease nitric oxide (NO) release, a hallmark of endothelial dysfunction. Here we report that chronic high Na+ damages the endothelial glycocalyx (eGC), induces release of inflammatory cytokines from the endothelium and promotes monocyte adhesion. Single cell force spectroscopy reveals that high Na+ enhances vascular adhesion protein-1 (VCAM-1)-dependent adhesion forces between monocytes and endothelial surface, giving rise to increased numbers of adherent monocytes on the endothelial surface. Mineralocorticoid receptor antagonism with spironolactone prevents high Na+-induced eGC deterioration, decreases monocyte-endothelium interactions, and restores endothelial function, indicated by increased release of NO. Whereas high Na+ decreases NO release, it induces endothelial release of the pro-inflammatory cytokines IL-1ß and TNFα. However, in contrast to chronic salt load (hours), in vivo and in vitro, an acute salt challenge (minutes) does not impair eGC function. This study identifies the eGC as important mediator of inflammatory processes and might further explain how dietary salt contributes to endothelialitis and cardiovascular pathologies by linking endothelial nanomechanics with vascular inflammation.
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Affiliation(s)
- Florian Schierke
- Institute of Physiology II, University of Münster, 48149 Münster, Germany
| | - Margot J Wyrwoll
- Institute of Physiology II, University of Münster, 48149 Münster, Germany
| | - Martin Wisdorf
- Institute of Physiology II, University of Münster, 48149 Münster, Germany
| | - Leon Niedzielski
- Institute of Physiology II, University of Münster, 48149 Münster, Germany
| | - Martina Maase
- Institute of Physiology II, University of Münster, 48149 Münster, Germany
| | - Tobias Ruck
- Department of Neurology, University of Münster, 48149 Münster, Germany
| | - Sven G Meuth
- Department of Neurology, University of Münster, 48149 Münster, Germany
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21
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Antonio LS, Jeggle P, MacVinish LJ, Bartram JC, Miller H, Jarvis GE, Levy FM, Santesso MR, Leite AL, Oliveira RC, Buzalaf MAR, Edwardson JM. The effect of fluoride on the structure, function, and proteome of a renal epithelial cell monolayer. ENVIRONMENTAL TOXICOLOGY 2017; 32:1455-1467. [PMID: 27548804 DOI: 10.1002/tox.22338] [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: 03/29/2016] [Revised: 08/08/2016] [Accepted: 08/08/2016] [Indexed: 06/06/2023]
Abstract
High concentrations of fluoride in the body may cause toxic effects. Here, we investigated the effects of fluoride on the structure, function, and proteome of a cortical collecting duct epithelium in vitro. Kidney tubule cells (M-1) were chosen because the concentration of fluoride in the kidney is 4-5-fold higher than that in plasma. Mouse M-1 cell monolayers were incubated in fluoride-containing media, and the amiloride-sensitive short-circuit current and transepithelial resistance were measured. The Young's modulus of the epithelium was determined using atomic force microscopy, and the effect of fluoride on epithelial structure was assessed using scanning and transmission electron microscopy, and immunofluorescence. Differences in the expression of membrane proteins were evaluated using proteomics and bioinformatics. Fluoride exposure reduced both transepithelial Na+ transport and resistance. The IC50 for fluoride was ∼300 µM for both effects, and the half-times for the decays of ion transport and resistance were 8.4 h and 3.6 days, respectively. Fluoride treatment did not affect the sensitivity of Na+ transport to amiloride. The Young's modulus of the epithelium was also unaffected by fluoride; however, the functional effects of fluoride were accompanied by marked structural effects. Proteomic analysis revealed changes in expression of a number of proteins, and particularly mitochondrial proteins. Treatment with fluoride had profound effects on the structure, function and proteome of a model cortical collecting duct epithelium. Significantly, however, these effects were produced only at concentrations considerably higher than those likely to be encountered in vivo. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1455-1467, 2017.
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Affiliation(s)
- Ligia S Antonio
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Pia Jeggle
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Lesley J MacVinish
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - James C Bartram
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Henry Miller
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Gavin E Jarvis
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Flávia M Levy
- Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil
| | - Mariana R Santesso
- Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil
| | - Aline L Leite
- Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil
| | - Rodrigo C Oliveira
- Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil
| | - Marília A R Buzalaf
- Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil
| | - J Michael Edwardson
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
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22
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Cox TR, Madsen CD. Relative Stiffness Measurements of Cell-embedded Hydrogels by Shear Rheology in vitro. Bio Protoc 2017; 7:e2101. [PMID: 34458430 DOI: 10.21769/bioprotoc.2101] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Revised: 10/07/2016] [Accepted: 12/06/2016] [Indexed: 11/02/2022] Open
Abstract
Hydrogel systems composed of purified extracellular matrix (ECM) components (such as collagen, fibrin, Matrigel, and methylcellulose) are a mainstay of cell and molecular biology research. They are used extensively in many applications including tissue regeneration platforms, studying organ development, and pathological disease models such as cancer. Both the biochemical and biomechanical properties influence cellular and tissue compatibility, and these properties are altered in pathological disease progression (Cox and Erler, 2011; Bonnans et al., 2014 ). The use of cell-embedded hydrogels in disease models such as cancer, allow the interrogation of cell-induced changes in the biomechanics of the microenvironment ( Madsen et al., 2015 ). Here we report a simple method to measure these cell-induced changes in vitro using a controlled strain rotational rheometer.
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Affiliation(s)
- Thomas R Cox
- The Garvan Institute of Medical Research and The Kinghorn Cancer Centre, Cancer Division, St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, Australia
| | - Chris D Madsen
- Department of Laboratory Medicine, Division of Translational Cancer Research, Lund University, Lund, Sweden
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23
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Kim Y, Kim W, Park JW. Principles and Applications of Force Spectroscopy Using Atomic Force Microscopy. B KOREAN CHEM SOC 2016. [DOI: 10.1002/bkcs.11022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Youngkyu Kim
- Department of Chemistry; Pohang University of Science and Technology; Pohang 37673 Korea
| | - Woong Kim
- Department of Chemistry; Pohang University of Science and Technology; Pohang 37673 Korea
| | - Joon Won Park
- Department of Chemistry; Pohang University of Science and Technology; Pohang 37673 Korea
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24
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25
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Jeggle P, Hofschröer V, Maase M, Bertog M, Kusche‐Vihrog K. Aldosterone synthase knockout mouse as a model for sodium‐induced endothelial sodium channel up‐regulation in vascular endothelium. FASEB J 2015; 30:45-53. [DOI: 10.1096/fj.14-259606] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 08/13/2015] [Indexed: 12/31/2022]
Affiliation(s)
- Pia Jeggle
- Institute of Physiology II, University of MunsterMunsterGermany
| | | | - Martina Maase
- Institute of Physiology II, University of MunsterMunsterGermany
| | - Marko Bertog
- Institut für Zelluläre und Molekulare Physiologie, Friedrich‐Alexander Universität Erlangen‐NürnbergErlangenGermany
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26
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Szymonski M, Targosz-Korecka M, Malek-Zietek KE. Nano-mechanical model of endothelial dysfunction for AFM-based diagnostics at the cellular level. Pharmacol Rep 2015; 67:728-35. [DOI: 10.1016/j.pharep.2015.05.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 05/04/2015] [Accepted: 05/06/2015] [Indexed: 12/17/2022]
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27
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Goreham RV, Thompson VC, Samura Y, Gibson CT, Shapter JG, Köper I. Interaction of silver nanoparticles with tethered bilayer lipid membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:5868-5874. [PMID: 25950498 DOI: 10.1021/acs.langmuir.5b00586] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Silver nanoparticles are well-known for their antibacterial properties. However, the detailed mechanism describing the interaction between the nanoparticles and a cell membrane is not fully understood, which can impede the use of the particles in biomedical applications. Here, a tethered bilayer lipid membrane has been used as a model system to mimic a natural membrane and to study the effect of exposure to small silver nanoparticles with diameters of about 2 nm. The solid supported membrane architecture allowed for the application of surface analytical techniques such as electrochemical impedance spectroscopy and atomic force microscopy. Exposure of the membrane to solutions of the silver nanoparticles led to a small but completely reversible perturbation of the lipid bilayer.
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Affiliation(s)
- Renee V Goreham
- Flinders Centre for NanoScale Science and Technology and School of Chemical and Physical Sciences, Flinders University, Bedford Park, SA, Australia 5042
| | - Vanessa C Thompson
- Flinders Centre for NanoScale Science and Technology and School of Chemical and Physical Sciences, Flinders University, Bedford Park, SA, Australia 5042
| | - Yuya Samura
- Flinders Centre for NanoScale Science and Technology and School of Chemical and Physical Sciences, Flinders University, Bedford Park, SA, Australia 5042
| | - Christopher T Gibson
- Flinders Centre for NanoScale Science and Technology and School of Chemical and Physical Sciences, Flinders University, Bedford Park, SA, Australia 5042
| | - Joseph G Shapter
- Flinders Centre for NanoScale Science and Technology and School of Chemical and Physical Sciences, Flinders University, Bedford Park, SA, Australia 5042
| | - Ingo Köper
- Flinders Centre for NanoScale Science and Technology and School of Chemical and Physical Sciences, Flinders University, Bedford Park, SA, Australia 5042
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28
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Kohn JC, Lampi MC, Reinhart-King CA. Age-related vascular stiffening: causes and consequences. Front Genet 2015; 6:112. [PMID: 25926844 PMCID: PMC4396535 DOI: 10.3389/fgene.2015.00112] [Citation(s) in RCA: 229] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 03/03/2015] [Indexed: 01/18/2023] Open
Abstract
Arterial stiffening occurs with age and is closely associated with the progression of cardiovascular disease. Stiffening is most often studied at the level of the whole vessel because increased stiffness of the large arteries can impose increased strain on the heart leading to heart failure. Interestingly, however, recent evidence suggests that the impact of increased vessel stiffening extends beyond the tissue scale and can also have deleterious microscale effects on cellular function. Altered extracellular matrix (ECM) architecture has been recognized as a key component of the pre-atherogenic state. Here, the underlying causes of age-related vessel stiffening are discussed, focusing on age-related crosslinking of the ECM proteins as well as through increased matrix deposition. Methods to measure vessel stiffening at both the macro- and microscale are described, spanning from the pulse wave velocity measurements performed clinically to microscale measurements performed largely in research laboratories. Additionally, recent work investigating how arterial stiffness and the changes in the ECM associated with stiffening contributed to endothelial dysfunction will be reviewed. We will highlight how changes in ECM protein composition contribute to atherosclerosis in the vessel wall. Lastly, we will discuss very recent work that demonstrates endothelial cells (ECs) are mechano-sensitive to arterial stiffening, where changes in stiffness can directly impact EC health. Overall, recent studies suggest that stiffening is an important clinical target not only because of potential deleterious effects on the heart but also because it promotes cellular level dysfunction in the vessel wall, contributing to a pathological atherosclerotic state.
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Affiliation(s)
- Julie C Kohn
- Department of Biomedical Engineering, Cornell University Ithaca, NY, USA
| | - Marsha C Lampi
- Department of Biomedical Engineering, Cornell University Ithaca, NY, USA
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29
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Puricelli L, Galluzzi M, Schulte C, Podestà A, Milani P. Nanomechanical and topographical imaging of living cells by atomic force microscopy with colloidal probes. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2015; 86:033705. [PMID: 25832236 DOI: 10.1063/1.4915896] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Atomic Force Microscopy (AFM) has a great potential as a tool to characterize mechanical and morphological properties of living cells; these properties have been shown to correlate with cells' fate and patho-physiological state in view of the development of novel early-diagnostic strategies. Although several reports have described experimental and technical approaches for the characterization of cellular elasticity by means of AFM, a robust and commonly accepted methodology is still lacking. Here, we show that micrometric spherical probes (also known as colloidal probes) are well suited for performing a combined topographic and mechanical analysis of living cells, with spatial resolution suitable for a complete and accurate mapping of cell morphological and elastic properties, and superior reliability and accuracy in the mechanical measurements with respect to conventional and widely used sharp AFM tips. We address a number of issues concerning the nanomechanical analysis, including the applicability of contact mechanical models and the impact of a constrained contact geometry on the measured Young's modulus (the finite-thickness effect). We have tested our protocol by imaging living PC12 and MDA-MB-231 cells, in order to demonstrate the importance of the correction of the finite-thickness effect and the change in Young's modulus induced by the action of a cytoskeleton-targeting drug.
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Affiliation(s)
- Luca Puricelli
- CIMaINa and Department of Physics, Università degli Studi di Milano, Via Celoria 16, 20133 Milano, Italy
| | - Massimiliano Galluzzi
- CIMaINa and Department of Physics, Università degli Studi di Milano, Via Celoria 16, 20133 Milano, Italy
| | - Carsten Schulte
- CIMaINa and Department of Physics, Università degli Studi di Milano, Via Celoria 16, 20133 Milano, Italy
| | - Alessandro Podestà
- CIMaINa and Department of Physics, Università degli Studi di Milano, Via Celoria 16, 20133 Milano, Italy
| | - Paolo Milani
- CIMaINa and Department of Physics, Università degli Studi di Milano, Via Celoria 16, 20133 Milano, Italy
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30
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Investigation of resins suitable for the preparation of biological sample for 3-D electron microscopy. J Struct Biol 2014; 189:135-46. [PMID: 25433274 DOI: 10.1016/j.jsb.2014.10.009] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 10/15/2014] [Accepted: 10/17/2014] [Indexed: 11/20/2022]
Abstract
In the last two decades, the third-dimension has become a focus of attention in electron microscopy to better understand the interactions within subcellular compartments. Initially, transmission electron tomography (TEM tomography) was introduced to image the cell volume in semi-thin sections (∼ 500 nm). With the introduction of the focused ion beam scanning electron microscope, a new tool, FIB-SEM tomography, became available to image much larger volumes. During TEM tomography and FIB-SEM tomography, the resin section is exposed to a high electron/ion dose such that the stability of the resin embedded biological sample becomes an important issue. The shrinkage of a resin section in each dimension, especially in depth, is a well-known phenomenon. To ensure the dimensional integrity of the final volume of the cell, it is important to assess the properties of the different resins and determine the formulation which has the best stability in the electron/ion beam. Here, eight different resin formulations were examined. The effects of radiation damage were evaluated after different times of TEM irradiation. To get additional information on mass-loss and the physical properties of the resins (stiffness and adhesion), the topography of the irradiated areas was analysed with atomic force microscopy (AFM). Further, the behaviour of the resins was analysed after ion milling of the surface of the sample with different ion currents. In conclusion, two resin formulations, Hard Plus and the mixture of Durcupan/Epon, emerged that were considerably less affected and reasonably stable in the electron/ion beam and thus suitable for the 3-D investigation of biological samples.
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31
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Ghoneum A, Zhu H, Woo J, Zabinyakov N, Sharma S, Gimzewski JK. Biophysical and morphological effects of nanodiamond/nanoplatinum solution (DPV576) on metastatic murine breast cancer cells in vitro. NANOTECHNOLOGY 2014; 25:465101. [PMID: 25360614 DOI: 10.1088/0957-4484/25/46/465101] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Nanoparticles have recently gained increased attention as drug delivery systems for the treatment of cancer due to their minute size and unique chemical properties. However, very few studies have tested the biophysical changes associated with nanoparticles on metastatic cancer cells at the cellular and sub-cellular scales. Here, we investigated the mechanical and morphological properties of cancer cells by measuring the changes in cell Young's Modulus using AFM, filopodial retraction (FR) by time lapse optical light microscopy imaging and filopodial disorganization by high resolution AFM imaging of cells upon treatment with nanoparticles. In the current study, nanomechanical changes in live murine metastatic breast cancer cells (4T1) post exposure to a nanodiamond/nanoplatinum mixture dispersed in aqueous solution (DPV576), were monitored. Results showed a decrease in Young's modulus at two hours post treatment with DPV576 in a dose dependent manner. Partial FR at 20 min and complete FR at 40 min were observed. Moreover, analysis of the retraction distance (in microns) measured over time (minutes), showed that a DPV576 concentration of 15%v/v yielded the highest FR rate. In addition, DPV576 treated cells showed early signs of filopodial disorganization and disintegration. This study demonstrates the changes in cell stiffness and tracks early structural alterations of metastatic breast cancer cells post treatment with DPV576, which may have important implications in the role of nanodiamond/nanoplatinum based cancer cell therapy and sensitization to chemotherapy drugs.
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Affiliation(s)
- Alia Ghoneum
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California, USA
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32
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Structural transitions and energy landscape for Cowpea Chlorotic Mottle Virus capsid mechanics from nanomanipulation in vitro and in silico. Biophys J 2014; 105:1893-903. [PMID: 24138865 DOI: 10.1016/j.bpj.2013.08.032] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2013] [Revised: 08/20/2013] [Accepted: 08/26/2013] [Indexed: 12/23/2022] Open
Abstract
Physical properties of capsids of plant and animal viruses are important factors in capsid self-assembly, survival of viruses in the extracellular environment, and their cell infectivity. Combined AFM experiments and computational modeling on subsecond timescales of the indentation nanomechanics of Cowpea Chlorotic Mottle Virus capsid show that the capsid's physical properties are dynamic and local characteristics of the structure, which change with the depth of indentation and depend on the magnitude and geometry of mechanical input. Under large deformations, the Cowpea Chlorotic Mottle Virus capsid transitions to the collapsed state without substantial local structural alterations. The enthalpy change in this deformation state ΔHind = 11.5-12.8 MJ/mol is mostly due to large-amplitude out-of-plane excitations, which contribute to the capsid bending; the entropy change TΔSind = 5.1-5.8 MJ/mol is due to coherent in-plane rearrangements of protein chains, which mediate the capsid stiffening. Direct coupling of these modes defines the extent of (ir)reversibility of capsid indentation dynamics correlated with its (in)elastic mechanical response to the compressive force. This emerging picture illuminates how unique physico-chemical properties of protein nanoshells help define their structure and morphology, and determine their viruses' biological function.
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Progress in measuring biophysical properties of membrane proteins with AFM single-molecule force spectroscopy. ACTA ACUST UNITED AC 2014. [DOI: 10.1007/s11434-014-0290-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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34
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Abstract
The mechanical characteristics of endothelial cells reveal four distinct compartments, namely glycocalyx, cell cortex, cytoplasm and nucleus. There is accumulating evidence that endothelial nanomechanics of these individual compartments control vascular physiology. Depending on protein composition, filament formation and interaction with cross-linker proteins, these four compartments determine endothelial stiffness. Structural organization and mechanical properties directly influence physiological processes such as endothelial barrier function, nitric oxide release and gene expression. This review will focus on endothelial nanomechanics and its impact on vascular function.
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Calò A, Reguera D, Oncins G, Persuy MA, Sanz G, Lobasso S, Corcelli A, Pajot-Augy E, Gomila G. Force measurements on natural membrane nanovesicles reveal a composition-independent, high Young's modulus. NANOSCALE 2014; 6:2275-2285. [PMID: 24407152 DOI: 10.1039/c3nr05107b] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Mechanical properties of nano-sized vesicles made up of natural membranes are crucial to the development of stable, biocompatible nanocontainers with enhanced functional, recognition and sensing capabilities. Here we measure and compare the mechanical properties of plasma and inner membrane nanovesicles ∼80 nm in diameter obtained from disrupted yeast Saccharomyces cerevisiae cells. We provide evidence of a highly deformable behaviour for these vesicles, able to support repeated wall-to-wall compressions without irreversible deformations, accompanied by a noticeably high Young's modulus (∼300 MPa) compared to that obtained for reconstituted artificial liposomes of similar size and approaching that of some virus particles. Surprisingly enough, the results are approximately similar for plasma and inner membrane nanovesicles, in spite of their different lipid compositions, especially on what concerns the ergosterol content. These results point towards an important structural role of membrane proteins in the mechanical response of natural membrane vesicles and open the perspective to their potential use as robust nanocontainers for bioapplications.
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Affiliation(s)
- Annalisa Calò
- IBEC Institute for Bioengineering of Catalonia, C/Baldiri Reixac 10-12, 08028, Barcelona, Spain.
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36
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Antibiotic-induced modifications of the stiffness of bacterial membranes. J Microbiol Methods 2013; 93:80-4. [DOI: 10.1016/j.mimet.2013.01.022] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 01/31/2013] [Accepted: 01/31/2013] [Indexed: 11/23/2022]
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Jeggle P, Callies C, Tarjus A, Fassot C, Fels J, Oberleithner H, Jaisser F, Kusche-Vihrog K. Epithelial sodium channel stiffens the vascular endothelium in vitro and in Liddle mice. Hypertension 2013; 61:1053-9. [PMID: 23460285 DOI: 10.1161/hypertensionaha.111.199455] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Liddle syndrome, an inherited form of hypertension, is caused by gain-of-function mutations in the epithelial Na(+) channel (ENaC), the principal mediator of Na(+) reabsorption in the kidney. Accordingly, the disease pathology was ascribed to a primary renal mechanism. Whether this is the sole responsible mechanism, however, remains uncertain as dysregulation of ENaC in other tissues may also be involved. Previous work indicates that ENaC in the vascular endothelium is crucial for the regulation of cellular mechanics and thus vascular function. The hormone aldosterone has been shown to concomitantly increase ENaC surface expression and stiffness of the cell cortex in vascular endothelial cells. The latter entails a reduced release of the vasodilator nitric oxide, which eventually leads to an increase in vascular tone and blood pressure. Using atomic force microscopy, we have found a direct correlation between ENaC surface expression and the formation of cortical stiffness in endothelial cells. Stable knockdown of αENaC in endothelial cells evoked a reduced channel surface density and a lower cortical stiffness compared with the mock control. In turn, an increased αENaC expression induced an elevated cortical stiffness. More importantly, using ex vivo preparations from a mouse model for Liddle syndrome, we show that this disorder evokes enhanced ENaC expression and increased cortical stiffness in vascular endothelial cells in situ. We conclude that ENaC in the vascular endothelium determines cellular mechanics and hence might participate in the control of vascular function.
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Affiliation(s)
- Pia Jeggle
- Institute of Physiology II, University of Muenster, Muenster, Germany
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Kasas S, Radotic K, Longo G, Saha B, Alonso-Sarduy L, Dietler G, Roduit C. A universal fluid cell for the imaging of biological specimens in the atomic force microscope. Microsc Res Tech 2013; 76:357-63. [PMID: 23390022 DOI: 10.1002/jemt.22174] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Accepted: 12/30/2012] [Indexed: 11/06/2022]
Abstract
Recently, atomic force microscope (AFM) manufacturers have begun producing instruments specifically designed to image biological specimens. In most instances, they are integrated with an inverted optical microscope, which permits concurrent optical and AFM imaging. An important component of the set-up is the imaging chamber, whose design determines the nature of the experiments that can be conducted. Many different imaging chamber designs are available, usually designed to optimize a single parameter, such as the dimensions of the substrate or the volume of fluid that can be used throughout the experiment. In this report, we present a universal fluid cell, which simultaneously optimizes all of the parameters that are important for the imaging of biological specimens in the AFM. This novel imaging chamber has been successfully tested using mammalian, plant, and microbial cells.
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Affiliation(s)
- Sandor Kasas
- Laboratoire de Physique de la Matière Vivante, EPFL, CH-1015, Lausanne, Switzerland.
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Last JA, Thomasy SM, Croasdale CR, Russell P, Murphy CJ. Compliance profile of the human cornea as measured by atomic force microscopy. Micron 2012; 43:1293-8. [PMID: 22421334 PMCID: PMC3622051 DOI: 10.1016/j.micron.2012.02.014] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2011] [Revised: 02/17/2012] [Accepted: 02/17/2012] [Indexed: 11/30/2022]
Abstract
The ability to accurately determine the elastic modulus of each layer of the human cornea is a crucial step in the design of better corneal prosthetics. In addition, knowledge of the elastic modulus will allow design of substrates with relevant mechanical properties for in vitro investigations of cellular behavior. Previously, we have reported elastic modulus values for the anterior basement membrane and Descemet's membrane of the human cornea, the surfaces in contact with the epithelial and endothelial cells, respectively. We have completed the compliance profile of the stromal elements of the human cornea by obtaining elastic modulus values for Bowman's layer and the anterior stroma. Atomic force microscopy (AFM) was used to determine the elastic modulus, which is a measure of the tissue stiffness and is inversely proportional to the compliance. The elastic response of the tissue allows analysis with the Hertz equation, a model that provides a relationship between the indentation force and depth and is a function of the tip radius and the modulus of the substrate. The elastic modulus values for each layer of the cornea are: 7.5±4.2 kPa (anterior basement membrane), 109.8±13.2 kPa (Bowman's layer), 33.1±6.1 kPa (anterior stroma), and 50±17.8 kPa (Descemet's membrane). These results indicate that the biophysical properties, including elastic modulus, of each layer of the human cornea are unique and may play a role in the maintenance of homeostasis as well as in the response to therapeutic agents and disease states. The data will also inform the design and fabrication of improved corneal prosthetics.
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Affiliation(s)
- Julie A. Last
- Laboratory for Optical and Computational Instrumentation and the Materials Science Center, University of Wisconsin-Madison
| | - Sara M. Thomasy
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis
| | | | - Paul Russell
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis
| | - Christopher J. Murphy
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis
- Department of Ophthalmology and Vision Science, School of Medicine, University of California, Davis
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40
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Nanoscale mechanical properties of lipid bilayers and their relevance in biomembrane organization and function. Micron 2012; 43:1212-23. [DOI: 10.1016/j.micron.2012.03.013] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Revised: 03/19/2012] [Accepted: 03/20/2012] [Indexed: 12/27/2022]
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Fels J, Jeggle P, Kusche-Vihrog K, Oberleithner H. Cortical actin nanodynamics determines nitric oxide release in vascular endothelium. PLoS One 2012; 7:e41520. [PMID: 22844486 PMCID: PMC3402397 DOI: 10.1371/journal.pone.0041520] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Accepted: 06/21/2012] [Indexed: 02/05/2023] Open
Abstract
The release of the main vasodilator nitric oxide (NO) by the endothelial NO synthase (eNOS) is a hallmark of endothelial function. We aim at elucidating the underlying mechanism how eNOS activity depends on cortical stiffness (К(cortex)) of living endothelial cells. It is hypothesized that cortical actin dynamics determines К(cortex) and directly influences eNOS activity. By combined atomic force microscopy and fluorescence imaging we generated mechanical and optical sections of single living cells. This approach allows the discrimination between К(cortex) and bulk cell stiffness (К(bulk)) and, additionally, the simultaneous analysis of submembranous actin web dynamics. We show that К(cortex) softens when cortical F-actin depolymerizes and that this shift from a gel-like stiff cortex to a soft G-actin rich layer, triggers the stiffness-sensitive eNOS activity. The results implicate that stiffness changes in the ∼100 nm phase of the submembranous actin web, without affecting К(bulk), regulate NO release and thus determines endothelial function.
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Affiliation(s)
- Johannes Fels
- Institute of Physiology II, University of Muenster, Muenster, Germany.
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43
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Measuring the elastic properties of living cells through the analysis of current-displacement curves in scanning ion conductance microscopy. Pflugers Arch 2012; 464:307-16. [PMID: 22744227 DOI: 10.1007/s00424-012-1127-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2012] [Revised: 06/05/2012] [Accepted: 06/07/2012] [Indexed: 12/21/2022]
Abstract
Knowledge of mechanical properties of living cells is essential to understand their physiological and pathological conditions. To measure local cellular elasticity, scanning probe techniques have been increasingly employed. In particular, non-contact scanning ion conductance microscopy (SICM) has been used for this purpose; thanks to the application of a hydrostatic pressure via the SICM pipette. However, the measurement of sample deformations induced by weak pressures at a short distance has not yet been carried out. A direct quantification of the applied pressure has not been also achieved up to now. These two issues are highly relevant, especially when one addresses the investigation of thin cell regions. In this paper, we present an approach to solve these problems based on the use of a setup integrating SICM, atomic force microscopy, and optical microscopy. In particular, we describe how we can directly image the pipette aperture in situ. Additionally, we can measure the force induced by a constant hydrostatic pressure applied via the pipette over the entire probe-sample distance range from a remote point to contact. Then, we demonstrate that the sample deformation induced by an external pressure applied to the pipette can be indirectly and reliably evaluated from the analysis of the current-displacement curves. This method allows us to measure the linear relationship between indentation and applied pressure on uniformly deformable elastomers of known Young's modulus. Finally, we apply the method to murine fibroblasts and we show that it is sensitive to local and temporally induced variations of the cell surface elasticity.
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Abstract
Vascular endothelium plays a key role in blood pressure regulation. Recently, it has been shown that a 5% increase of plasma sodium concentration (sodium excess) stiffens endothelial cells by about 25%, leading to cellular dysfunction. Surface measurements demonstrated that the endothelial glycocalyx (eGC), an anionic biopolymer, deteriorates when sodium is elevated. In view of these results, a two-barrier model for sodium exiting the circulation across the endothelium is suggested. The first sodium barrier is the eGC which selectively buffers sodium ions with its negatively charged proteoglycans. The second sodium barrier is the endothelial plasma membrane which contains sodium channels. Sodium excess, in the presence of aldosterone, leads to eGC break-down and, in parallel, to an up-regulation of plasma membrane sodium channels. The following hypothesis is postulated: Sodium excess increases vascular sodium permeability. Under such conditions (e.g. high-sodium diet), day-by-day ingested sodium, instead of being readily buffered by the eGC and then rapidly excreted by the kidneys, is distributed in the whole body before being finally excreted. Gradually, the sodium overload damages the organism.
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Affiliation(s)
- Hans Oberleithner
- Institute of Physiology II, University of Münster, Münster, Germany.
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45
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Targosz-Korecka M, Biedron R, Szczygiel AM, Brzezinka G, Szczerbinski J, Zuk A. Stiffness changes of tumor HEp2 cells correlates with the inhibition and release of TRAIL-induced apoptosis pathways. J Mol Recognit 2012; 25:299-308. [DOI: 10.1002/jmr.2192] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
| | - Rafal Biedron
- Chair of Immunology, Medical College; Jagiellonian University; Czysta 18; 31-121; Krakow; Poland
| | | | - Grzegorz Brzezinka
- Institute of Physics; Jagiellonian University; Reymonta 4; 30-059; Krakow; Poland
| | - Jacek Szczerbinski
- Institute of Physics; Jagiellonian University; Reymonta 4; 30-059; Krakow; Poland
| | - Anna Zuk
- Institute of Physics; Jagiellonian University; Reymonta 4; 30-059; Krakow; Poland
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46
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Longo G, Rio LM, Roduit C, Trampuz A, Bizzini A, Dietler G, Kasas S. Force volume and stiffness tomography investigation on the dynamics of stiff material under bacterial membranes. J Mol Recognit 2012; 25:278-84. [DOI: 10.1002/jmr.2171] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Giovanni Longo
- Laboratory of Physics of Living Matter; EPFL; Lausanne; Switzerland
| | - Laura Marques Rio
- Infectious Diseases Service, Department of Medicine; University Hospital Lausanne (CHUV); Lausanne; Switzerland
| | - Charles Roduit
- Laboratory of Physics of Living Matter; EPFL; Lausanne; Switzerland
| | - Andrej Trampuz
- Infectious Diseases Service, Department of Medicine; University Hospital Lausanne (CHUV); Lausanne; Switzerland
| | | | - Giovanni Dietler
- Laboratory of Physics of Living Matter; EPFL; Lausanne; Switzerland
| | - Sandor Kasas
- Laboratory of Physics of Living Matter; EPFL; Lausanne; Switzerland
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47
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Fernandes AN, Chen X, Scotchford CA, Walker J, Wells DM, Roberts CJ, Everitt NM. Mechanical properties of epidermal cells of whole living roots of Arabidopsis thaliana: an atomic force microscopy study. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 85:021916. [PMID: 22463253 DOI: 10.1103/physreve.85.021916] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Revised: 08/10/2011] [Indexed: 05/06/2023]
Abstract
The knowledge of mechanical properties of root cell walls is vital to understand how these properties interact with relevant genetic and physiological processes to bring about growth. Expansion of cell walls is an essential component of growth, and the regulation of cell wall expansion is one of the ways in which the mechanics of growth is controlled, managed and directed. In this study, the inherent surface mechanical properties of living Arabidopsis thaliana whole-root epidermal cells were studied at the nanoscale using the technique of atomic force microscopy (AFM). A novel methodology was successfully developed to adapt AFM to live plant roots. Force-Indentation (F-I) experiments were conducted to investigate the mechanical properties along the length of the root. F-I curves for epidermal cells of roots were also generated by varying turgor pressure. The F-I curves displayed a variety of features due to the heterogeneity of the surface. Hysteresis is observed. Application of conventional models to living biological systems such as cell walls in nanometer regimes tends to increase error margins to a large extent. Hence information from the F-I curves were used in a preliminary semiquantitative analysis to infer material properties and calculate two parameters. The work done in the loading and unloading phases (hysteresis) of the force measurements were determined separately and were expressed in terms of "Index of Plasticity" (η), which characterized the elasticity properties of roots as a viscoelastic response. Scaling approaches were used to find the ratio of hardness to reduced modulus (H/E(*)).
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Affiliation(s)
- Anwesha N Fernandes
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, England LE12 5RD.
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48
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Measurement of nanomechanical properties of biomolecules using atomic force microscopy. Micron 2012; 43:116-28. [DOI: 10.1016/j.micron.2011.07.017] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Revised: 07/29/2011] [Accepted: 07/30/2011] [Indexed: 12/27/2022]
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Peters W, Drüppel V, Kusche-Vihrog K, Schubert C, Oberleithner H. Nanomechanics and sodium permeability of endothelial surface layer modulated by hawthorn extract WS 1442. PLoS One 2012; 7:e29972. [PMID: 22253842 PMCID: PMC3254622 DOI: 10.1371/journal.pone.0029972] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Accepted: 12/09/2011] [Indexed: 12/12/2022] Open
Abstract
The endothelial glycocalyx (eGC) plays a pivotal role in the physiology of the vasculature. By binding plasma proteins, the eGC forms the endothelial surface layer (ESL) which acts as an interface between bloodstream and endothelial cell surface. The functions of the eGC include mechanosensing of blood flow induced shear stress and thus flow dependent vasodilation. There are indications that levels of plasma sodium concentrations in the upper range of normal and beyond impair flow dependent regulation of blood pressure and may therefore increase the risk for hypertension. Substances, therefore, that prevent sodium induced endothelial dysfunction may be attractive for the treatment of cardiovascular disease. By means of combined atomic force - epifluorescence microscopy we studied the impact of the hawthorn (Crataegus spp.) extract WS 1442, a herbal therapeutic with unknown mechanism of action, on the mechanics of the ESL of ex vivo murine aortae. Furthermore, we measured the impact of WS 1442 on the sodium permeability of endothelial EA.hy 926 cell monolayer. The data show that (i) the ESL contributes by about 11% to the total endothelial barrier resistance for sodium and (ii) WS 1442 strengthens the ESL resistance for sodium up to about 45%. This mechanism may explain some of the vasoprotective actions of this herbal therapeutic.
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Affiliation(s)
- Wladimir Peters
- Institute of Physiology II, University of Münster, Münster, Germany.
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50
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Ramachandran S, Teran Arce F, Lal R. Potential role of atomic force microscopy in systems biology. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2011; 3:702-16. [PMID: 21766465 DOI: 10.1002/wsbm.154] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Systems biology is a quantitative approach for understanding a biological system at its global level through systematic perturbation and integrated analysis of all its components. Simultaneous acquisition of information data sets pertaining to the system components (e.g., genome, proteome) is essential to implement this approach. There are limitations to such an approach in measuring gene expression levels and accounting for all proteins in the system. The success of genomic studies is critically dependent on polymerase chain reaction (PCR) for its amplification, but PCR is very uneven in amplifying the samples, ineffective in scarce samples and unreliable in low copy number transcripts. On the other hand, lack of amplifying techniques for proteins critically limits their identification to only a small fraction of high concentration proteins. Atomic force microscopy (AFM), AFM cantilever sensors, and AFM force spectroscopy in particular, could address these issues directly. In this article, we reviewed and assessed their potential role in systems biology.
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