151
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Shashikanth N, Petrova YI, Park S, Chekan J, Maiden S, Spano M, Ha T, Gumbiner BM, Leckband DE. Allosteric Regulation of E-Cadherin Adhesion. J Biol Chem 2015; 290:21749-61. [PMID: 26175155 DOI: 10.1074/jbc.m115.657098] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Indexed: 11/06/2022] Open
Abstract
Cadherins are transmembrane adhesion proteins that maintain intercellular cohesion in all tissues, and their rapid regulation is essential for organized tissue remodeling. Despite some evidence that cadherin adhesion might be allosterically regulated, testing of this has been hindered by the difficulty of quantifying altered E-cadherin binding affinity caused by perturbations outside the ectodomain binding site. Here, measured kinetics of cadherin-mediated intercellular adhesion demonstrated quantitatively that treatment with activating, anti-E-cadherin antibodies or the dephosphorylation of a cytoplasmic binding partner, p120(ctn), increased the homophilic binding affinity of E-cadherin. Results obtained with Colo 205 cells, which express inactive E-cadherin and do not aggregate, demonstrated that four treatments, which induced Colo 205 aggregation and p120(ctn) dephosphorylation, triggered quantitatively similar increases in E-cadherin affinity. Several processes can alter cell aggregation, but these results directly demonstrated the allosteric regulation of cell surface E-cadherin by p120(ctn) dephosphorylation.
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Affiliation(s)
| | - Yuliya I Petrova
- the Department of Cell Biology, School of Medicine, University of Virginia, Charlottesville, Virginia 22908, and
| | | | - Jillian Chekan
- Chemical and Biomolecular Engineering, University of Illinois, Urbana-Champaign, Illinois 61801
| | - Stephanie Maiden
- the Department of Cell Biology, School of Medicine, University of Virginia, Charlottesville, Virginia 22908, and
| | - Martha Spano
- the Department of Cell Biology, School of Medicine, University of Virginia, Charlottesville, Virginia 22908, and
| | - Taekjip Ha
- From the Departments of Biochemistry, Physics, and the Howard Hughes Medical Institute, Urbana, Illinois 61801
| | - Barry M Gumbiner
- the Department of Cell Biology, School of Medicine, University of Virginia, Charlottesville, Virginia 22908, and
| | - Deborah E Leckband
- From the Departments of Biochemistry, Chemical and Biomolecular Engineering, University of Illinois, Urbana-Champaign, Illinois 61801,
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152
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Kuo TY, Tseng WH, Chen CH. Force Spectroscopy of Metal-Crown Ether Multivalency: Effect of Local Environments on Energy Landscape and Sensing Kinetics. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201503948] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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153
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Kuo TY, Tseng WH, Chen CH. Force Spectroscopy of Metal-Crown Ether Multivalency: Effect of Local Environments on Energy Landscape and Sensing Kinetics. Angew Chem Int Ed Engl 2015; 54:9213-7. [DOI: 10.1002/anie.201503948] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Indexed: 11/09/2022]
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154
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Mugler A, Tans SJ, Mashaghi A. Circuit topology of self-interacting chains: implications for folding and unfolding dynamics. Phys Chem Chem Phys 2015; 16:22537-44. [PMID: 25228051 DOI: 10.1039/c4cp03402c] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Understanding the relationship between molecular structure and folding is a central problem in disciplines ranging from biology to polymer physics and DNA origami. Topology can be a powerful tool to address this question. For a folded linear chain, the arrangement of intra-chain contacts is a topological property because rearranging the contacts requires discontinuous deformations. Conversely, the topology is preserved when continuously stretching the chain while maintaining the contact arrangement. Here we investigate how the folding and unfolding of linear chains with binary contacts is guided by the topology of contact arrangements. We formalize the topology by describing the relations between any two contacts in the structure, which for a linear chain can either be in parallel, in series, or crossing each other. We show that even when other determinants of folding rate such as contact order and size are kept constant, this 'circuit' topology determines folding kinetics. In particular, we find that the folding rate increases with the fractions of parallel and crossed relations. Moreover, we show how circuit topology constrains the conformational phase space explored during folding and unfolding: the number of forbidden unfolding transitions is found to increase with the fraction of parallel relations and to decrease with the fraction of series relations. Finally, we find that circuit topology influences whether distinct intermediate states are present, with crossed contacts being the key factor. The approach presented here can be more generally applied to questions on molecular dynamics, evolutionary biology, molecular engineering, and single-molecule biophysics.
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Affiliation(s)
- Andrew Mugler
- Department of Physics, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907, USA
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155
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Nguyen TH, Greinacher A, Delcea M. Quantitative description of thermodynamic and kinetic properties of the platelet factor 4/heparin bonds. NANOSCALE 2015; 7:10130-9. [PMID: 25981976 DOI: 10.1039/c5nr02132d] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Heparin is the most important antithrombotic drug in hospitals. It binds to the endogenous tetrameric protein platelet factor 4 (PF4) forming PF4/heparin complexes which may cause a severe immune-mediated adverse drug reaction, so-called heparin-induced thrombocytopenia (HIT). Although new heparin drugs have been synthesized to reduce such a risk, detailed bond dynamics of the PF4/heparin complexes have not been clearly understood. In this study, single molecule force spectroscopy (SMFS) is utilized to characterize the interaction of PF4 with heparins of defined length (5-, 6-, 8-, 12-, and 16-mers). Analysis of the force-distance curves shows that PF4/heparin binding strength rises with increasing heparin length. In addition, two binding pathways in the PF4/short heparins (≤8-mers) and three binding pathways in the PF4/long heparins (≥8-mers) are identified. We provide a model for the PF4/heparin complexes in which short heparins bind to one PF4 tetramer, while long heparins bind to two PF4 tetramers. We propose that the interaction between long heparins and PF4s is not only due to charge differences as generally assumed, but also due to hydrophobic interaction between two PF4s which are brought close to each other by long heparin. This complicated interaction induces PF4/heparin complexes more stable than other ligand-receptor interactions. Our results also reveal that the boundary between antigenic and non-antigenic heparins is between 8- and 12-mers. These observations are particularly important to understand processes in which PF4-heparin interactions are involved and to develop new heparin-derived drugs.
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Affiliation(s)
- Thi-Huong Nguyen
- Nanostructure Group, ZIK HIKE - Center for Innovation Competence, Humoral Immune Reactions in Cardiovascular Diseases, Ernst-Moritz-Arndt-Universität Greifswald, 17489 Greifswald, Germany.
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156
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te Riet J, Reinieren-Beeren I, Figdor CG, Cambi A. AFM force spectroscopy reveals how subtle structural differences affect the interaction strength betweenCandida albicansand DC-SIGN. J Mol Recognit 2015; 28:687-98. [DOI: 10.1002/jmr.2481] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Revised: 04/24/2015] [Accepted: 04/27/2015] [Indexed: 11/07/2022]
Affiliation(s)
- Joost te Riet
- Department of Tumor Immunology; Radboud Institute for Molecular Life Sciences, Radboud UMC; P.O. Box 9101 6500HB Nijmegen The Netherlands
| | - Inge Reinieren-Beeren
- Department of Tumor Immunology; Radboud Institute for Molecular Life Sciences, Radboud UMC; P.O. Box 9101 6500HB Nijmegen The Netherlands
| | - Carl G. Figdor
- Department of Tumor Immunology; Radboud Institute for Molecular Life Sciences, Radboud UMC; P.O. Box 9101 6500HB Nijmegen The Netherlands
| | - Alessandra Cambi
- Department of Tumor Immunology; Radboud Institute for Molecular Life Sciences, Radboud UMC; P.O. Box 9101 6500HB Nijmegen The Netherlands
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157
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Two-tiered coupling between flowing actin and immobilized N-cadherin/catenin complexes in neuronal growth cones. Proc Natl Acad Sci U S A 2015; 112:6997-7002. [PMID: 26038554 DOI: 10.1073/pnas.1423455112] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Neuronal growth cones move forward by dynamically connecting actin-based motility to substrate adhesion, but the mechanisms at the individual molecular level remain unclear. We cultured primary neurons on N-cadherin-coated micropatterned substrates, and imaged adhesion and cytoskeletal proteins at the ventral surface of growth cones using single particle tracking combined to photoactivated localization microscopy (sptPALM). We demonstrate transient interactions in the second time scale between flowing actin filaments and immobilized N-cadherin/catenin complexes, translating into a local reduction of the actin retrograde flow. Normal actin flow on micropatterns was rescued by expression of a dominant negative N-cadherin construct competing for the coupling between actin and endogenous N-cadherin. Fluorescence recovery after photobleaching (FRAP) experiments confirmed the differential kinetics of actin and N-cadherin, and further revealed a 20% actin population confined at N-cadherin micropatterns, contributing to local actin accumulation. Computer simulations with relevant kinetic parameters modeled N-cadherin and actin turnover well, validating this mechanism. Such a combination of short- and long-lived interactions between the motile actin network and spatially restricted adhesive complexes represents a two-tiered clutch mechanism likely to sustain dynamic environment sensing and provide the force necessary for growth cone migration.
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158
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Petrosyan R, Bippes CA, Walheim S, Harder D, Fotiadis D, Schimmel T, Alsteens D, Müller DJ. Single-molecule force spectroscopy of membrane proteins from membranes freely spanning across nanoscopic pores. NANO LETTERS 2015; 15:3624-3633. [PMID: 25879249 DOI: 10.1021/acs.nanolett.5b01223] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Single-molecule force spectroscopy (SMFS) provides detailed insight into the mechanical (un)folding pathways and structural stability of membrane proteins. So far, SMFS could only be applied to membrane proteins embedded in native or synthetic membranes adsorbed to solid supports. This adsorption causes experimental limitations and raises the question to what extent the support influences the results obtained by SMFS. Therefore, we introduce here SMFS from native purple membrane freely spanning across nanopores. We show that correct analysis of the SMFS data requires extending the worm-like chain model, which describes the mechanical stretching of a polypeptide, by the cubic extension model, which describes the bending of a purple membrane exposed to mechanical stress. This new experimental and theoretical approach allows to characterize the stepwise (un)folding of the membrane protein bacteriorhodopsin and to assign the stability of single and grouped secondary structures. The (un)folding and stability of bacteriorhodopsin shows no significant difference between freely spanning and directly supported purple membranes. Importantly, the novel experimental SMFS setup opens an avenue to characterize any protein from freely spanning cellular or synthetic membranes.
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Affiliation(s)
- Rafayel Petrosyan
- ‡Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule (ETH) Zurich, 4058 Basel, Switzerland
| | - Christian A Bippes
- ‡Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule (ETH) Zurich, 4058 Basel, Switzerland
| | - Stefan Walheim
- †Institute of Applied Physics and Center for Functional Nanostructures (CFN) and Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), 76021 Karlsruhe, Germany
| | - Daniel Harder
- §Institute of Biochemistry and Molecular Medicine, University of Bern, 3012 Bern, Switzerland
| | - Dimitrios Fotiadis
- §Institute of Biochemistry and Molecular Medicine, University of Bern, 3012 Bern, Switzerland
| | - Thomas Schimmel
- †Institute of Applied Physics and Center for Functional Nanostructures (CFN) and Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), 76021 Karlsruhe, Germany
| | - David Alsteens
- ‡Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule (ETH) Zurich, 4058 Basel, Switzerland
| | - Daniel J Müller
- ‡Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule (ETH) Zurich, 4058 Basel, Switzerland
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159
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Prasad A, Huefner A, Mahajan S, Seshia AA. Investigating biomechanical noise in neuroblastoma cells using the quartz crystal microbalance. J R Soc Interface 2015; 12:rsif.2014.1389. [PMID: 25878129 DOI: 10.1098/rsif.2014.1389] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Quantifying cellular behaviour by motility and morphology changes is increasingly important in formulating an understanding of fundamental physiological phenomena and cellular mechanisms of disease. However, cells are complex biological units, which often respond to external environmental factors by manifesting subtle responses that may be difficult to interpret using conventional biophysical measurements. This paper describes the adaptation of the quartz crystal microbalance (QCM) to monitor neuroblastoma cells undergoing environmental stress wherein the frequency stability of the device can be correlated to changes in cellular state. By employing time domain analysis of the resulting frequency fluctuations, it is possible to study the variations in cellular motility and distinguish between different cell states induced by applied external heat stress. The changes in the frequency fluctuation data are correlated to phenotypical physical response recorded using optical microscopy under identical conditions of environmental stress. This technique, by probing the associated biomechanical noise, paves the way for its use in monitoring cell activity, and intrinsic motility and morphology changes, as well as the modulation resulting from the action of drugs, toxins and environmental stress.
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Affiliation(s)
- Abhinav Prasad
- Nanoscience Centre, Department of Engineering, University of Cambridge, 11 JJ Thomson Avenue, Cambridge CB3 0FF, UK
| | - Anna Huefner
- Cavendish Laboratory, Department of Physics, University of Cambridge, 19 JJ Thomson Avenue, Cambridge CB3 0HE, UK Institute of Life Sciences, University of Southampton, Highfield, Southampton SO17 1BJ, UK
| | - Sumeet Mahajan
- Institute of Life Sciences, University of Southampton, Highfield, Southampton SO17 1BJ, UK
| | - Ashwin A Seshia
- Nanoscience Centre, Department of Engineering, University of Cambridge, 11 JJ Thomson Avenue, Cambridge CB3 0FF, UK
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160
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Frey EW, Li J, Wijeratne SS, Kiang CH. Reconstructing multiple free energy pathways of DNA stretching from single molecule experiments. J Phys Chem B 2015; 119:5132-5. [PMID: 25825924 DOI: 10.1021/jp511348r] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Free energy landscapes provide information on the dynamics of proteins and nucleic acid folding. It has been demonstrated that such landscapes can be reconstructed from single molecule force measurement data using Jarzynski's equality, which requires only stretching data. However, when the process is reversible, the Crooks fluctuation theorem combines both stretch and relaxation force data for the analysis and can offer more rapid convergence of free energy estimates of different states. Here we demonstrate that, similar to Jarzynski's equality, the Crooks fluctuation theorem can be used to reconstruct the full free energy landscapes. In addition, when the free energy landscapes exhibit multiple folding pathways, one can use Jarzynski's equality to reconstruct individual free energy pathways if the experimental data show distinct work distributions. We applied the method to reconstruct the overstretching transition of poly(dA) to demonstrate that the nonequilibrium work theorem combined with single molecule force measurements provides a clear picture of the free energy landscapes.
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Affiliation(s)
- Eric W Frey
- †Department of Physics and Astronomy and ‡Department of Bioengineering, Rice University, Houston, Texas 77005, United States
| | - Jingqiang Li
- †Department of Physics and Astronomy and ‡Department of Bioengineering, Rice University, Houston, Texas 77005, United States
| | - Sithara S Wijeratne
- †Department of Physics and Astronomy and ‡Department of Bioengineering, Rice University, Houston, Texas 77005, United States
| | - Ching-Hwa Kiang
- †Department of Physics and Astronomy and ‡Department of Bioengineering, Rice University, Houston, Texas 77005, United States
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161
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Podlipec R, Štrancar J. Cell-scaffold adhesion dynamics measured in first seconds predicts cell growth on days scale – optical tweezers study. ACS APPLIED MATERIALS & INTERFACES 2015; 7:6782-6791. [PMID: 25764169 DOI: 10.1021/acsami.5b00235] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Understanding the cell-biomaterial interface from the very first contact is of crucial importance for their successful implementation and function in damaged tissues. However, the lack of bio- and mechano-analytical methods to investigate and probe the initial processes on the interface, especially in 3D, raises the need for applying new experimental techniques. In our study, optical tweezers combined with confocal fluorescence microscopy were optimized to investigate the initial cell-scaffold contact and to investigate its correlation with the material-dependent cell growth. By the optical tweezers-induced cell manipulation accompanied by force detection up to 100 pN and position detection by fluorescence microscopy, accurate adhesion dynamics and strength analysis was implemented, where several attachment sites were formed on the interface in the first few seconds. More importantly, we have shown that dynamics of cell adhesion on scaffold surfaces correlates with cell growth on the days scale, which indicates that the first seconds of the contact could markedly direct further cell response. Such a contact dynamics analysis on 3D scaffold surfaces, applied for the first time, can thus serve to predict scaffold biocompatibility.
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Affiliation(s)
- Rok Podlipec
- Centre of Excellence NAMASTE, Jamova cesta 39, SI-1000 Ljubljana, Slovenia
- Laboratory of Biophysics, Condensed Matter Physics Department, "Jožef Stefan" Institute, Jamova cesta 39, Ljubljana SI-1000, Slovenia
| | - Janez Štrancar
- Centre of Excellence NAMASTE, Jamova cesta 39, SI-1000 Ljubljana, Slovenia
- Laboratory of Biophysics, Condensed Matter Physics Department, "Jožef Stefan" Institute, Jamova cesta 39, Ljubljana SI-1000, Slovenia
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162
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Force-induced on-rate switching and modulation by mutations in gain-of-function von Willebrand diseases. Proc Natl Acad Sci U S A 2015; 112:4648-53. [PMID: 25810255 DOI: 10.1073/pnas.1501689112] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Mutations in the ultralong vascular protein von Willebrand factor (VWF) cause the common human bleeding disorder, von Willebrand disease (VWD). The A1 domain in VWF binds to glycoprotein Ibα (GPIbα) on platelets, in a reaction triggered, in part, by alterations in flow during bleeding. Gain-of-function mutations in A1 and GPIbα in VWD suggest conformational regulation. We report that force application switches A1 and/or GPIbα to a second state with faster on-rate, providing a mechanism for activating VWF binding to platelets. Switching occurs near 10 pN, a force that also induces a state of the receptor-ligand complex with slower off-rate. Force greatly increases the effects of VWD mutations, explaining pathophysiology. Conversion of single molecule kon (s(-1)) to bulk phase kon (s(-1)M(-1)) and the kon and koff values extrapolated to zero force for the low-force pathways show remarkably good agreement with bulk-phase measurements.
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163
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Papadopulos A, Gomez GA, Martin S, Jackson J, Gormal RS, Keating DJ, Yap AS, Meunier FA. Activity-driven relaxation of the cortical actomyosin II network synchronizes Munc18-1-dependent neurosecretory vesicle docking. Nat Commun 2015; 6:6297. [DOI: 10.1038/ncomms7297] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2014] [Accepted: 01/14/2015] [Indexed: 01/08/2023] Open
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164
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Shi R, Cui H, Bi Y, Huang X, Song B, Cheng C, Zhang L, Liu J, He C, Wang F, Jia Z, Yang B, Wang J, Dong J, DU Z, Xiao S, Cui Y, Cheng X. Artesunate altered cellular mechanical properties leading to deregulation of cell proliferation and migration in esophageal squamous cell carcinoma. Oncol Lett 2015; 9:2249-2255. [PMID: 26137051 DOI: 10.3892/ol.2015.2982] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 02/10/2015] [Indexed: 11/05/2022] Open
Abstract
Esophageal squamous cell carcinoma (ESCC) is one of the most common types of cancer in China. Artesunate (ART) is used clinically as an anti-malarial agent and exhibits potent antiproliferative activity. In addition, ART has demonstrated remarkable antitumor activity, presenting a novel candidate for cancer chemotherapy. However, its effect on ESCC remains unknown. The present study analyzed the antitumor effects of ART in the KYSE-150 ESCC line by assessing cell proliferation, cell death, cell migration/invasion and the biomechanical properties of ART-treated KYSE-150 cells. ART treatment significantly suppressed the proliferation of KYSE-150 cells in a dose- and time-dependent manner, as assessed by MTT assay. Following treatment with 30 mg/l ART, the cell population in the G0/G1 phase and the level of cell apoptosis significantly increased from 54±1.5 to 68.1±0.3%, and from 4.53±0.58 to 12.45±0.62%, respectively. Furthermore, the cell migration and invasion of KYSE-150 cells treated with 30 mg/l ART was markedly inhibited. The cell membrane and biomechanical properties were investigated using atomic force microscopy, as targets of ART action. ESCC cells treated with 30 mg/l ART exhibited increased adhesive force, increased cytomembrane roughness and reduced elasticity compared with the control group (KYSE-150 cells without ART treatment). The biomechanical properties of KYSE-150 cells treated with 30 mg/l ART were similar to those of the SHEE normal human esophageal epithelial cell line. In conclusion, the present study demonstrated that ART may inhibit cell proliferation and migration in ESCC through changes in the biomechanical properties of the ESCC cells.
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Affiliation(s)
- Ruyi Shi
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China ; Department of Cell Biology and Genetics, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
| | - Heyang Cui
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China ; Department of Cell Biology and Genetics, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
| | - Yanghui Bi
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China ; Department of Cell Biology and Genetics, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
| | - Xun Huang
- Department of Materials Science and Engineering, Jinan University, Guangzhou, Guangdong 510630, P.R. China
| | - Bin Song
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China ; Department of Oncology, The First Hospital, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
| | - Caixia Cheng
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China ; Department of Cell Biology and Genetics, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China ; Department of Pathology, The First Hospital, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
| | - Ling Zhang
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China ; Department of Cell Biology and Genetics, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China ; Department of Pathology, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
| | - Jing Liu
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China ; Department of General Surgery, The First Hospital, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
| | - Chanting He
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China ; Department of Cell Biology and Genetics, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
| | - Fang Wang
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
| | - Zhiwu Jia
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
| | - Bin Yang
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
| | - Juan Wang
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China ; Department of Cell Biology and Genetics, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
| | - Jinyao Dong
- Department of General Surgery, The First Hospital, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
| | - Zhijie DU
- Department of General Surgery, The First Hospital, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
| | - Shuaishuai Xiao
- Department of General Surgery, The First Hospital, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
| | - Yongping Cui
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China ; Department of Cell Biology and Genetics, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
| | - Xiaolong Cheng
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China ; Institute of Dissection, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
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165
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Ushiyama A, Ono M, Kataoka-Hamai C, Taguchi T, Kaizuka Y. Induction of intermembrane adhesion by incorporation of synthetic adhesive molecules into cell membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:1988-1998. [PMID: 25614390 DOI: 10.1021/la504523c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Modulation of cell adhesion by synthetic materials is useful for a wide range of biomedical applications. Here, we characterized cell adhesion mediated by a semisynthetic molecule, cholesteryl-modified gelatin (chol-gelatin). We found that this hybrid molecule facilitated cell adhesion by connecting two apposed membranes via multiple cholesterol moieties on the gelatin molecules, whereas unmodified gelatin did not bind to cell membranes. Analyses revealed that the rate of the formation of cell adhesions was increased by displaying more cholesterol moieties on the cell membrane. In contrast, the area of the cell adhesion site was unchanged by increasing the number of cholesterol molecules, suggesting that chol-gelatin may suppress cell spreading. Such restriction was not observed in cell adhesion mediated by the mutant of physiological adhesion protein CD2, which lacked its cytoplasmic domain and was unable to connect to cytoplasmic actin filaments, but had a similar affinity for its ligand compared with the chol-gelatin-cell membrane interaction. Further analysis suggested the restriction of cell spreading by chol-gelatin was largely independent of the modulation of the surface force, and thus we hypothesize that the restriction could be in part due to the modulation of cell membrane mechanics by membrane-incorporated chol-gelatin. Our study dissected the two roles of the hybrid molecule in cell adhesion, namely the formation of a molecular connection and the restriction of spreading, and may be useful for designing other novel synthetic agents to modulate various types of cell adhesions.
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Affiliation(s)
- Ai Ushiyama
- National Institute for Materials Science, International Center for Materials Nanoarchitectonics , 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
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166
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Wang C, Jin Y, Desai UR, Yadavalli VK. Investigation of the heparin-thrombin interaction by dynamic force spectroscopy. Biochim Biophys Acta Gen Subj 2015; 1850:1099-106. [PMID: 25647100 DOI: 10.1016/j.bbagen.2015.01.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 01/08/2015] [Accepted: 01/25/2015] [Indexed: 11/28/2022]
Abstract
BACKGROUND The interaction between heparin and thrombin is a vital step in the blood (anti)coagulation process. Unraveling the molecular basis of the interactions is therefore extremely important in understanding the mechanisms of this complex biological process. METHODS In this study, we use a combination of an efficient thiolation chemistry of heparin, a self-assembled monolayer-based single molecule platform, and a dynamic force spectroscopy to provide new insights into the heparin-thrombin interaction from an energy viewpoint at the molecular scale. RESULTS Well-separated single molecules of heparin covalently attached to mixed self-assembled monolayers are demonstrated, whereby interaction forces with thrombin can be measured via atomic force microscopy-based spectroscopy. Further these interactions are studied at different loading rates and salt concentrations to directly obtain kinetic parameters. CONCLUSIONS An increase in the loading rate shows a higher interaction force between the heparin and thrombin, which can be directly linked to the kinetic dissociation rate constant (koff). The stability of the heparin/thrombin complex decreased with increasing NaCl concentration such that the off-rate was found to be driven primarily by non-ionic forces. GENERAL SIGNIFICANCE These results contribute to understanding the role of specific and nonspecific forces that drive heparin-thrombin interactions under applied force or flow conditions.
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Affiliation(s)
- Congzhou Wang
- Department of Chemical and Life Science Engineering, Virginia Commonwealth University, Richmond VA 23284, United States
| | - Yingzi Jin
- Department of Medicinal Chemistry, Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, VA 23298, United States
| | - Umesh R Desai
- Department of Medicinal Chemistry, Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, VA 23298, United States
| | - Vamsi K Yadavalli
- Department of Chemical and Life Science Engineering, Virginia Commonwealth University, Richmond VA 23284, United States.
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167
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Chen X, Mao Z, Chen B. Probing time-dependent mechanical behaviors of catch bonds based on two-state models. Sci Rep 2015; 5:7868. [PMID: 25598078 PMCID: PMC4297987 DOI: 10.1038/srep07868] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 12/11/2014] [Indexed: 01/13/2023] Open
Abstract
With lifetime counter-intuitively being prolonged under forces, catch bonds can play critical roles in various sub-cellular processes. By adopting different “catching” strategies within the framework of two-state models, we construct two types of catch bonds that have a similar force-lifetime profile upon a constant force-clamp load. However, when a single catch bond of either type is subjected to varied forces, we find that they can behave very differently in both force history dependence and bond strength. We further find that a cluster of catch bonds of either type generally becomes unstable when subjected to a periodically oscillating force, which is consistent with experimental results. These results provide important insights into versatile time-dependent mechanical behaviors of catch bonds. We suggest that it is necessary to further differentiate those bonds that are all phenomenologically referred to as “Catch bonds”.
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Affiliation(s)
- Xiaofeng Chen
- Department of Engineering Mechanics, Zhejiang University, Hangzhou 310027, P. R. China
| | - Zhixiu Mao
- Department of Engineering Mechanics, Zhejiang University, Hangzhou 310027, P. R. China
| | - Bin Chen
- Department of Engineering Mechanics, Zhejiang University, Hangzhou 310027, P. R. China
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168
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Cheng B, Cui S. Supramolecular Chemistry and Mechanochemistry of Macromolecules: Recent Advances by Single-Molecule Force Spectroscopy. Top Curr Chem (Cham) 2015; 369:97-134. [DOI: 10.1007/128_2015_628] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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169
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Chen S, Lu X, Hu Y, Lu Q. Biomimetic honeycomb-patterned surface as the tunable cell adhesion scaffold. Biomater Sci 2015. [DOI: 10.1039/c4bm00233d] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PS honeycomb structured surfaces were modified into both cell-philic and cell-phobic by dip-coating and casting polySBMA, respectively, which was inspired by two typically adhesive behaviours of fish skin and Parthenocissus tricuspidata.
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Affiliation(s)
- Shuangshuang Chen
- School of Chemistry and Chemical Engineering
- State Key Laboratory of Metal Matrix Composite
- Shanghai Jiao Tong University
- Shanghai 200240
- People's Republic of China
| | - Xuemin Lu
- School of Chemistry and Chemical Engineering
- State Key Laboratory of Metal Matrix Composite
- Shanghai Jiao Tong University
- Shanghai 200240
- People's Republic of China
| | - Ying Hu
- School of Chemistry and Chemical Engineering
- State Key Laboratory of Metal Matrix Composite
- Shanghai Jiao Tong University
- Shanghai 200240
- People's Republic of China
| | - Qinghua Lu
- School of Chemistry and Chemical Engineering
- State Key Laboratory of Metal Matrix Composite
- Shanghai Jiao Tong University
- Shanghai 200240
- People's Republic of China
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170
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Hydrogen Bonding in Supramolecular Polymer Networks: Glasses, Melts, and Elastomers. SUPRAMOLECULAR POLYMER NETWORKS AND GELS 2015. [DOI: 10.1007/978-3-319-15404-6_2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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171
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Haugstad KE, Stokke BT, Brewer CF, Gerken TA, Sletmoen M. Single molecule study of heterotypic interactions between mucins possessing the Tn cancer antigen. Glycobiology 2014; 25:524-34. [PMID: 25527429 DOI: 10.1093/glycob/cwu183] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Mucins are linear, heavily O-glycosylated proteins with physiological roles that include cell signaling, cell adhesion, inflammation, immune response and tumorgenesis. Cancer-associated mucins often differ from normal mucins by presenting truncated carbohydrate chains. Characterization of the binding properties of mucins with truncated carbohydrate side chains could thus prove relevant for understanding their role in cancer mechanisms such as metastasis and recognition by the immune system. In this work, heterotypic interactions of model mucins that possess the Tn (GalNAcαThr/Ser) and T (Galβ1-3GalNAcαThr/Ser) cancer antigens derived from porcine submaxillary mucin (PSM) were studied using atomic force microscopy. PSM possessing only the Tn antigen (Tn-PSM) was found to bind to PSM analogs possessing a combination of T, Tn and STn antigens as well as biosynthetic analogs of the core 1 blood group A tetrasaccharide (GalNAcα1-3[Fucα1-2] Galβ1-3GalNAcαSer/Thr). The rupture forces for the heterotypic interactions ranged from 18- to 31 pN at a force-loading rate of ∼0.5 nN/s. The thermally averaged distance from the bound complex to the transition state (xβ) was estimated to be in the range 0.37-0.87 nm for the first barrier of the Bell Evans analysis and within 0.34-0.64 nm based on a lifetime analysis. These findings reveal that the binding strength and energy landscape for heterotypic interactions of Tn-PSM with the above mucins, resemble homotypic interactions of Tn-PSM. This suggests common carbohydrate epitope interactions for the Tn cancer antigen with the above mucin analogs, a finding that may be important to the role of the Tn antigen in cancer cells.
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Affiliation(s)
- Kristin E Haugstad
- Department of Physics, Biophysics and Medical Technology, The Norwegian University of Science and Technology, Trondheim NO-7491, Norway
| | - Bjørn T Stokke
- Department of Physics, Biophysics and Medical Technology, The Norwegian University of Science and Technology, Trondheim NO-7491, Norway
| | - C Fred Brewer
- Department of Molecular Pharmacology Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Thomas A Gerken
- W.A. Bernbaum Center for Cystic Fibrosis Research, Departments of Pediatrics, Biochemistry and Chemistry, Case Western Reserve University School of Medicine, Cleveland, OH 44106-4948, USA
| | - Marit Sletmoen
- Department of Physics, Biophysics and Medical Technology, The Norwegian University of Science and Technology, Trondheim NO-7491, Norway
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172
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A microwell pattern for C17.2 cell aggregate formation with concave cylindrical surface induced cell peeling. Biomaterials 2014; 35:9423-37. [DOI: 10.1016/j.biomaterials.2014.07.046] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 07/23/2014] [Indexed: 01/17/2023]
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173
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Maciaszek JL, Partola K, Zhang J, Andemariam B, Lykotrafitis G. Single-cell force spectroscopy as a technique to quantify human red blood cell adhesion to subendothelial laminin. J Biomech 2014; 47:3855-61. [PMID: 25458578 DOI: 10.1016/j.jbiomech.2014.10.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 09/18/2014] [Accepted: 10/11/2014] [Indexed: 01/16/2023]
Abstract
Single-cell force spectroscopy (SCFS), an atomic force microscopy (AFM)-based assay, enables quantitative study of cell adhesion while maintaining the native state of surface receptors in physiological conditions. Human healthy and pathological red blood cells (RBCs) express a large number of surface proteins which mediate cell-cell interactions, or cell adhesion to the extracellular matrix. In particular, RBCs adhere with high affinity to subendothelial matrix laminin via the basal cell adhesion molecule and Lutheran protein (BCAM/Lu). Here, we established SCFS as an in vitro technique to study human RBC adhesion at baseline and following biochemical treatment. Using blood obtained from healthy human subjects, we recorded adhesion forces from single RBCs attached to AFM cantilevers as the cell was pulled-off of substrates coated with laminin protein. We found that an increase in the overall cell adhesion measured via SCFS is correlated with an increase in the resultant total force measured on 1 µm(2) areas of the RBC membrane. Further, we showed that SCFS can detect significant changes in the adhesive response of RBCs to modulation of the cyclic adenosine monophosphate (cAMP) and protein kinase A (PKA) pathway. Lastly, we identified variability in the RBC adhesion force to laminin amongst the human subjects, suggesting that RBCs maintain diverse levels of active BCAM/Lu adhesion receptors. By using single-cell measurements, we established a powerful new method for the quantitative measurement of single RBC adhesion with specific receptor-mediated binding.
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Affiliation(s)
- Jamie L Maciaszek
- Department of Biomedical Engineering, University of Connecticut, Storrs, CT, USA; Department of Hematology, Division of Experimental Hematology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Kostyantyn Partola
- Department of Mechanical Engineering, University of Connecticut, Storrs, CT, USA
| | - Jing Zhang
- Department of Mechanical Engineering, University of Connecticut, Storrs, CT, USA
| | - Biree Andemariam
- Adult Sickle Cell Disease Center, University of Connecticut Health Center, Farmington, CT, USA
| | - George Lykotrafitis
- Department of Biomedical Engineering, University of Connecticut, Storrs, CT, USA; Department of Mechanical Engineering, University of Connecticut, Storrs, CT, USA.
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174
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Affiliation(s)
- D.E. Leckband
- Departments of Chemical and Biomolecular Engineering, Chemistry, and Biochemistry, University of Illinois, Urbana, Illinois 61801;
| | - J. de Rooij
- Molecular Cancer Research, Center for Molecular Medicine, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands;
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175
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Exploiting the kinetic interplay between GPIbα-VWF binding interfaces to regulate hemostasis and thrombosis. Blood 2014; 124:3799-807. [PMID: 25293780 DOI: 10.1182/blood-2014-04-569392] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Platelet-von Willebrand factor (VWF) interactions must be tightly regulated in order to promote effective hemostasis and prevent occlusive thrombus formation. However, it is unclear what role the inherent properties of the bond formed between the platelet receptor glycoprotein Ibα and the A1 domain of VWF play in these processes. Using VWF-A1 knock-in mice with mutations that enhance (I1309V) or disrupt (R1326H) platelet receptor glycoprotein Ibα binding, we now demonstrate that the kinetic interplay between two distinct contact surfaces influences the site and extent to which platelets bind VWF. Incorporation of R1326H mutation into the major site shortened bond lifetime, yielding defects in hemostasis and thrombosis comparable to VWF-deficient animals. Similarly, disrupting this region of contact with an allosteric inhibitor impaired human platelet accrual in damaged arterioles. In contrast, the I1309V mutation near the minor site prolonged bond lifetime, which was essential for the development of a type 2B-like VWD phenotype. However, combining the R1326H and I1309V mutations normalized both bond kinetics and the hemostatic and thrombotic properties of VWF. These findings broaden our understanding of mechanisms governing platelet-VWF interactions in health and disease, and underscore the importance of combined biophysical and genetic approaches in identifying potential therapeutic avenues for treating bleeding and thrombotic disorders.
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176
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Anjukandi P, Dopieralski P, Ribas–Arino J, Marx D. The effect of tensile stress on the conformational free energy landscape of disulfide bonds. PLoS One 2014; 9:e108812. [PMID: 25286308 PMCID: PMC4186883 DOI: 10.1371/journal.pone.0108812] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 08/25/2014] [Indexed: 11/19/2022] Open
Abstract
Disulfide bridges are no longer considered to merely stabilize protein structure, but are increasingly recognized to play a functional role in many regulatory biomolecular processes. Recent studies have uncovered that the redox activity of native disulfides depends on their C-C-S-S dihedrals, χ2 and χ'2. Moreover, the interplay of chemical reactivity and mechanical stress of disulfide switches has been recently elucidated using force-clamp spectroscopy and computer simulation. The χ2 and χ'2 angles have been found to change from conformations that are open to nucleophilic attack to sterically hindered, so-called closed states upon exerting tensile stress. In view of the growing evidence of the importance of C-C-S-S dihedrals in tuning the reactivity of disulfides, here we present a systematic study of the conformational diversity of disulfides as a function of tensile stress. With the help of force-clamp metadynamics simulations, we show that tensile stress brings about a large stabilization of the closed conformers, thereby giving rise to drastic changes in the conformational free energy landscape of disulfides. Statistical analysis shows that native TDi, DO and interchain Ig protein disulfides prefer open conformations, whereas the intrachain disulfide bridges in Ig proteins favor closed conformations. Correlating mechanical stress with the distance between the two a-carbons of the disulfide moiety reveals that the strain of intrachain Ig protein disulfides corresponds to a mechanical activation of about 100 pN. Such mechanical activation leads to a severalfold increase of the rate of the elementary redox S(N)2 reaction step. All these findings constitute a step forward towards achieving a full understanding of functional disulfides.
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Affiliation(s)
- Padmesh Anjukandi
- Lehrstuhl für Theoretische Chemie, Ruhr–Universität Bochum, Bochum, Germany
- * E-mail:
| | - Przemyslaw Dopieralski
- Lehrstuhl für Theoretische Chemie, Ruhr–Universität Bochum, Bochum, Germany
- Faculty of Chemistry, University of Wroclaw, Wroclaw, Poland
| | - Jordi Ribas–Arino
- Lehrstuhl für Theoretische Chemie, Ruhr–Universität Bochum, Bochum, Germany
| | - Dominik Marx
- Lehrstuhl für Theoretische Chemie, Ruhr–Universität Bochum, Bochum, Germany
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177
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Greenfield BPJ, Lord AM, Dudley E, Butt TM. Conidia of the insect pathogenic fungus, Metarhizium anisopliae, fail to adhere to mosquito larval cuticle. ROYAL SOCIETY OPEN SCIENCE 2014; 1:140193. [PMID: 26064542 PMCID: PMC4448906 DOI: 10.1098/rsos.140193] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 09/23/2014] [Indexed: 05/12/2023]
Abstract
Adhesion of conidia of the insect pathogenic fungus, Metarhizium anisopliae, to the arthropod host cuticle initially involves hydrophobic forces followed by consolidation facilitated by the action of extracellular enzymes and secretion of mucilage. Gene expression analysis and atomic force microscopy were used to directly quantify recognition and adhesion between single conidia of M. anisopliae and the cuticle of the aquatic larval stage of Aedes aegypti and a representative terrestrial host, Tenebrio molitor. Gene expression data indicated recognition by the pathogen of both hosts; however, the forces for adhesion to the mosquito were approximately five times lower than those observed for Tenebrio. Although weak forces were recorded in response to Aedes, Metarhizium was unable to consolidate firm attachment. An analysis of the cuticular composition revealed an absence of long-chain hydrocarbons in Aedes larvae which are thought to be required for fungal development on host cuticle. This study provides, to our knowledge, the first evidence that Metarhizium does not form firm attachment to Ae. aegypti larvae in situ, therefore preventing the normal route of invasion and pathogenesis from occuring.
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Affiliation(s)
- Bethany P. J. Greenfield
- College of Science, Swansea University, Singleton Park, Swansea SA2 8PP, UK
- Author for correspondence: Bethany P. J. Greenfield e-mail:
| | - Alex M. Lord
- College of Engineering, Swansea University, Singleton Park, Swansea SA2 8PP, UK
| | - Ed Dudley
- College of Medicine, Swansea University, Singleton Park, Swansea SA2 8PP, UK
| | - Tariq M. Butt
- College of Science, Swansea University, Singleton Park, Swansea SA2 8PP, UK
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178
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Riggio C, Calatayud MP, Giannaccini M, Sanz B, Torres TE, Fernández-Pacheco R, Ripoli A, Ibarra MR, Dente L, Cuschieri A, Goya GF, Raffa V. The orientation of the neuronal growth process can be directed via magnetic nanoparticles under an applied magnetic field. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2014; 10:1549-58. [DOI: 10.1016/j.nano.2013.12.008] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Accepted: 12/23/2013] [Indexed: 12/15/2022]
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179
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Shi R, Bai Y, Li S, Wei H, Zhang X, Li L, Tian XC, Jiang Q, Wang C, Qin L, Cai J, Zhang S. Characteristics of spermatogonial stem cells derived from neonatal porcine testis. Andrologia 2014; 47:765-78. [PMID: 25251288 DOI: 10.1111/and.12327] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/16/2014] [Indexed: 12/18/2022] Open
Abstract
The aim of this study was to isolate and characterise porcine spermatogonial stem cells (PSSCs). The putative porcine germline stem cells from testis were isolated successfully by an improving way of enrichment with lymphocyte separation medium (LSM). Results from RT-PCR analyses showed that PSSCs were positive for OCT4, SOX2, NANOG, PGP9.5, c-MYC, KEL4 and PRDM-14 which are multipotent stem cell markers. At the protein level, the results of immunofluorescence analyses showed that PSSCs were positive for OCT4, PGP9.5, SOX2 and CD29. We successfully differentiated these PSSCs into adipocytes and muscle cells and then defined their characteristics, including morphology, surface stem cell markers, and mechanical properties. But the experiment of teratoma formation was negative. The results indicated the PSSCs could be multipotent. Atomic force microscopy was used to characterise the morphological and mechanical properties of undifferentiated PSSCs, as well as the differentiated adipocytes and muscle cells, which could be potentially useful for distinguishing PSSCs from differentiated cells.
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Affiliation(s)
- R Shi
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China.,Key Laboratory of Cellular Physiology, Ministry of Education, Department of Cell Biology and Genetics, Shanxi Medical University, Taiyuan, Shanxi, China
| | - Y Bai
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - S Li
- Life Science and Technology College, Jinan University, Guangzhou, China
| | - H Wei
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - X Zhang
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China.,South-China Primate Research and Development Center, Guangdong Entomological Institute, Guangzhou, China
| | - L Li
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - X C Tian
- Department of Animal Science/Center for Regenerative Biology, University of Connecticut, Storrs, CT, USA
| | - Q Jiang
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - C Wang
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - L Qin
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - J Cai
- Life Science and Technology College, Jinan University, Guangzhou, China
| | - S Zhang
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China
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180
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S S S, Sthanam LK, Padinhateeri R, Inamdar MM, Sen S. Probing cellular mechanoadaptation using cell-substrate de-adhesion dynamics: experiments and model. PLoS One 2014; 9:e106915. [PMID: 25197799 PMCID: PMC4157833 DOI: 10.1371/journal.pone.0106915] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 08/01/2014] [Indexed: 11/19/2022] Open
Abstract
Physical properties of the extracellular matrix (ECM) are known to regulate cellular processes ranging from spreading to differentiation, with alterations in cell phenotype closely associated with changes in physical properties of cells themselves. When plated on substrates of varying stiffness, fibroblasts have been shown to exhibit stiffness matching property, wherein cell cortical stiffness increases in proportion to substrate stiffness up to 5 kPa, and subsequently saturates. Similar mechanoadaptation responses have also been observed in other cell types. Trypsin de-adhesion represents a simple experimental framework for probing the contractile mechanics of adherent cells, with de-adhesion timescales shown to scale inversely with cortical stiffness values. In this study, we combine experiments and computation in deciphering the influence of substrate properties in regulating de-adhesion dynamics of adherent cells. We first show that NIH 3T3 fibroblasts cultured on collagen-coated polyacrylamide hydrogels de-adhere faster on stiffer substrates. Using a simple computational model, we qualitatively show how substrate stiffness and cell-substrate bond breakage rate collectively influence de-adhesion timescales, and also obtain analytical expressions of de-adhesion timescales in certain regimes of the parameter space. Finally, by comparing stiffness-dependent experimental and computational de-adhesion responses, we show that faster de-adhesion on stiffer substrates arises due to force-dependent breakage of cell-matrix adhesions. In addition to illustrating the utility of employing trypsin de-adhesion as a biophysical tool for probing mechanoadaptation, our computational results highlight the collective interplay of substrate properties and bond breakage rate in setting de-adhesion timescales.
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Affiliation(s)
- Soumya S S
- Department of Civil Engineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra, India
| | - Lakshmi Kavitha Sthanam
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra, India
| | - Ranjith Padinhateeri
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra, India
- * E-mail: (RP); (MMI); (SS)
| | - Mandar M. Inamdar
- Department of Civil Engineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra, India
- * E-mail: (RP); (MMI); (SS)
| | - Shamik Sen
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra, India
- * E-mail: (RP); (MMI); (SS)
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181
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Rakshit S, Sivasankar S. Biomechanics of cell adhesion: how force regulates the lifetime of adhesive bonds at the single molecule level. Phys Chem Chem Phys 2014; 16:2211-23. [PMID: 24419646 DOI: 10.1039/c3cp53963f] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Cell adhesion proteins play critical roles in positioning cells during development, segregating cells into distinct tissue compartments and in maintaining tissue integrity. The principle function of these proteins is to bind cells together and resist mechanical force. Adhesive proteins also enable migrating cells to adhere and roll on surfaces even in the presence of shear forces exerted by fluid flow. Recently, several experimental and theoretical studies have provided quantitative insights into the physical mechanisms by which adhesion proteins modulate their unbinding kinetics in response to tensile force. This perspective reviews these biophysical investigations. We focus on single molecule studies of cadherins, selectins, integrins, the von Willebrand factor and FimH adhesion proteins; the effect of mechanical force on the lifetime of these interactions has been extensively characterized. We review both theoretical models and experimental investigations and discuss future directions in this exciting area of research.
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Affiliation(s)
- Sabyasachi Rakshit
- Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA.
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182
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Liu N, Chen Y, Peng B, Lin Y, Wang Q, Su Z, Zhang W, Li H, Shen J. Single-molecule force spectroscopy study on the mechanism of RNA disassembly in tobacco mosaic virus. Biophys J 2014; 105:2790-800. [PMID: 24359751 DOI: 10.1016/j.bpj.2013.10.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 09/22/2013] [Accepted: 10/09/2013] [Indexed: 12/17/2022] Open
Abstract
To explore the disassembly mechanism of tobacco mosaic virus (TMV), a model system for virus study, during infection, we have used single-molecule force spectroscopy to mimic and follow the process of RNA disassembly from the protein coat of TMV by the replisome (molecular motor) in vivo, under different pH and Ca(2+) concentrations. Dynamic force spectroscopy revealed the unbinding free-energy landscapes as that at pH 4.7 the disassembly process is dominated by one free-energy barrier, whereas at pH 7.0 the process is dominated by one barrier and that there exists a second barrier. The additional free-energy barrier at longer distance has been attributed to the hindrance of disordered loops within the inner channel of TMV, and the biological function of those protein loops was discussed. The combination of pH increase and Ca(2+) concentration drop could weaken RNA-protein interactions so much that the molecular motor replisome would be able to pull and disassemble the rest of the genetic RNA from the protein coat in vivo. All these facts provide supporting evidence at the single-molecule level, to our knowledge for the first time, for the cotranslational disassembly mechanism during TMV infection under physiological conditions.
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Affiliation(s)
- Ningning Liu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, P. R. China; School of Chemistry and Material Science, Liaoning Shihua University, Fushun, P. R. China
| | - Ying Chen
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, P. R. China
| | - Bo Peng
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, P. R. China
| | - Yuan Lin
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, P. R. China
| | - Qian Wang
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, P. R. China; Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina.
| | - Zhaohui Su
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, P. R. China
| | - Wenke Zhang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, P. R. China.
| | - Hongbin Li
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, P. R. China; Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jiacong Shen
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, P. R. China
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183
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184
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Brüggemann D, Frohnmayer JP, Spatz JP. Model systems for studying cell adhesion and biomimetic actin networks. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2014; 5:1193-202. [PMID: 25161853 PMCID: PMC4142981 DOI: 10.3762/bjnano.5.131] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 06/25/2014] [Indexed: 05/28/2023]
Abstract
Many cellular processes, such as migration, proliferation, wound healing and tumor progression are based on cell adhesion. Amongst different cell adhesion molecules, the integrin receptors play a very significant role. Over the past decades the function and signalling of various such integrins have been studied by incorporating the proteins into lipid membranes. These proteolipid structures lay the foundation for the development of artificial cells, which are able to adhere to substrates. To build biomimetic models for studying cell shape and spreading, actin networks can be incorporated into lipid vesicles, too. We here review the mechanisms of integrin-mediated cell adhesion and recent advances in the field of minimal cells towards synthetic adhesion. We focus on reconstituting integrins into lipid structures for mimicking cell adhesion and on the incorporation of actin networks and talin into model cells.
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Affiliation(s)
- Dorothea Brüggemann
- Department of New Materials and Biosystems, Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, D-70569 Stuttgart, Germany
- Department of Biophysical Chemistry, University of Heidelberg, INF 253, D-69120 Heidelberg, Germany
| | - Johannes P Frohnmayer
- Department of New Materials and Biosystems, Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, D-70569 Stuttgart, Germany
- Department of Biophysical Chemistry, University of Heidelberg, INF 253, D-69120 Heidelberg, Germany
| | - Joachim P Spatz
- Department of New Materials and Biosystems, Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, D-70569 Stuttgart, Germany
- Department of Biophysical Chemistry, University of Heidelberg, INF 253, D-69120 Heidelberg, Germany
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185
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Fairhead M, Shen D, Chan LKM, Lowe ED, Donohoe TJ, Howarth M. Love-Hate ligands for high resolution analysis of strain in ultra-stable protein/small molecule interaction. Bioorg Med Chem 2014; 22:5476-86. [PMID: 25128469 DOI: 10.1016/j.bmc.2014.07.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 07/16/2014] [Accepted: 07/17/2014] [Indexed: 12/19/2022]
Abstract
The pathway of ligand dissociation and how binding sites respond to force are not well understood for any macromolecule. Force effects on biological receptors have been studied through simulation or force spectroscopy, but not by high resolution structural experiments. To investigate this challenge, we took advantage of the extreme stability of the streptavidin-biotin interaction, a paradigm for understanding non-covalent binding as well as a ubiquitous research tool. We synthesized a series of biotin-conjugates having an unchanged strong-binding biotin moiety, along with pincer-like arms designed to clash with the protein surface: 'Love-Hate ligands'. The Love-Hate ligands contained various 2,6-di-ortho aryl groups, installed using Suzuki coupling as the last synthetic step, making the steric repulsion highly modular. We determined binding affinity, as well as solving 1.1-1.6Å resolution crystal structures of streptavidin bound to Love-Hate ligands. Striking distortion of streptavidin's binding contacts was found for these complexes. Hydrogen bonds to biotin's ureido and thiophene rings were preserved for all the ligands, but biotin's valeryl tail was distorted from the classic conformation. Streptavidin's L3/4 loop, normally forming multiple energetically-important hydrogen bonds to biotin, was forced away by clashes with Love-Hate ligands, but Ser45 from L3/4 could adapt to hydrogen-bond to a different part of the ligand. This approach of preparing conflicted ligands represents a direct way to visualize strained biological interactions and test protein plasticity.
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Affiliation(s)
- Michael Fairhead
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Di Shen
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Louis K M Chan
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Ed D Lowe
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Timothy J Donohoe
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, UK.
| | - Mark Howarth
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
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186
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Abstract
Blood is renewed throughout the entire life. The stem cells of the blood, called hematopoietic stem cells (HSCs), are responsible for maintaining a supply of all types of fresh blood cells. In contrast to other stem cells, the clinical application of these cells is well established and HSC transplantation is an established life-saving therapy for patients suffering from haematological disorders. Despite their efficient functionality throughout life in vivo, controlling HSC behaviour in vitro (including their proliferation and differentiation) is still a major task that has not been resolved with standard cell culture systems. Targeted HSC multiplication in vitro could be beneficial for many patients, because HSC supply is limited. The biology of these cells and their natural microenvironment - their niche - remain a matter of ongoing research. In recent years, evidence has come to light that HSCs are susceptible to physical stimuli. This makes the regulation of HSCs by engineering physical parameters a promising approach for the targeted manipulation of these cells for clinical applications. Nevertheless, the biophysical regulation of these cells is still poorly understood. This review sheds light on the role of biophysical parameters in HSC biology and outlines which knowledge on biophysical regulation identified in other cell types could be applied to HSCs.
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Affiliation(s)
- C Lee-Thedieck
- Karlsruhe Institute of Technology (KIT), Institute of Functional Interfaces, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
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187
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Schubert R, Strohmeyer N, Bharadwaj M, Ramanathan SP, Krieg M, Friedrichs J, Franz CM, Muller DJ. Assay for characterizing the recovery of vertebrate cells for adhesion measurements by single-cell force spectroscopy. FEBS Lett 2014; 588:3639-48. [PMID: 24928443 DOI: 10.1016/j.febslet.2014.06.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 05/30/2014] [Accepted: 06/02/2014] [Indexed: 11/30/2022]
Abstract
Single-cell force spectroscopy (SCFS) is becoming a widely used method to quantify the adhesion of a living cell to a substrate, another cell or tissue. The high sensitivity of SCFS permits determining the contributions of individual cell adhesion molecules (CAMs) to the adhesion force of an entire cell. However, to prepare adherent cells for SCFS, they must first be detached from tissue-culture flasks or plates. EDTA and trypsin are often applied for this purpose. Because cellular properties can be affected by this treatment, cells need to recover before being further characterized by SCFS. Here we introduce atomic force microscopy (AFM)-based SCFS to measure the mechanical and adhesive properties of HeLa cells and mouse embryonic kidney fibroblasts while they are recovering after detachment from tissue-culture. We find that mechanical and adhesive properties of both cell lines recover quickly (<10 min) after detachment using EDTA, while trypsin-detached fibroblasts require >60 min to fully recover. Our assay introduced to characterize the recovery of mammalian cells after detachment can in future be used to estimate the recovery behavior of other adherent cell types.
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Affiliation(s)
- Rajib Schubert
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Nico Strohmeyer
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Mitasha Bharadwaj
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Subramanian P Ramanathan
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Michael Krieg
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA
| | - Jens Friedrichs
- Leibniz Institute of Polymer Research Dresden, Institute for Biofunctional Polymer Materials, Hohe Str. 6, 01069 Dresden, Germany
| | - Clemens M Franz
- Karlsruhe Institute of Technology (KIT), DFG-Center for Functional Nanostructures, Wolfgang-Gaede-Str. 1a, 76131 Karlsruhe, Germany
| | - Daniel J Muller
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland.
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188
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Chinnadurai R, Garcia M, Sakurai Y, Lam W, Kirk A, Galipeau J, Copland I. Actin cytoskeletal disruption following cryopreservation alters the biodistribution of human mesenchymal stromal cells in vivo. Stem Cell Reports 2014; 3:60-72. [PMID: 25068122 PMCID: PMC4110775 DOI: 10.1016/j.stemcr.2014.05.003] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 05/05/2014] [Accepted: 05/06/2014] [Indexed: 12/14/2022] Open
Abstract
Mesenchymal stromal cells have shown clinical promise; however, variations in treatment responses are an ongoing concern. We previously demonstrated that MSCs are functionally stunned after thawing. Here, we investigated whether this cryopreservation/thawing defect also impacts the postinfusion biodistribution properties of MSCs. Under both static and physiologic flow, compared with live MSCs in active culture, MSCs thawed from cryopreservation bound poorly to fibronectin (40% reduction) and human endothelial cells (80% reduction), respectively. This reduction correlated with a reduced cytoskeletal F-actin content in post-thaw MSCs (60% reduction). In vivo, live human MSCs could be detected in murine lung tissues for up to 24 hr, whereas thawed MSCs were undetectable. Similarly, live MSCs whose actin cytoskeleton was chemically disrupted were undetectable at 24 hr postinfusion. Our data suggest that post-thaw cryopreserved MSCs are distinct from live MSCs. This distinction could significantly affect the utility of MSCs as a cellular therapeutic. Immediately after thawing, MSCs display attenuated binding and engraftment potential Immediately after thawing, MSCs display defective actin polymerization Disrupting actin cytoskeleton in MSCs replicates post-thaw MSC engraftment defect A 48 hr culture recovery of MSCs post-thaw restores in vivo engraftment potential
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Affiliation(s)
- Raghavan Chinnadurai
- Department of Hematology and Oncology, Emory University School of Medicine, Atlanta, GA 30322, USA
- Winship Cancer Institute, Emory University, Atlanta, GA 30322, USA
| | | | - Yumiko Sakurai
- Department of Pediatrics, Emory University, Atlanta, GA 30322, USA
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Tech and Emory University, Atlanta, GA 30322, USA
| | - Wilbur A. Lam
- Department of Pediatrics, Emory University, Atlanta, GA 30322, USA
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Tech and Emory University, Atlanta, GA 30322, USA
| | - Allan D. Kirk
- Department of Surgery, Division of Transplantation, Emory University School of Medicine, Atlanta, GA 30322, USA
- Emory Transplant Center, Emory University, Atlanta, GA 30322, USA
| | - Jacques Galipeau
- Department of Hematology and Oncology, Emory University School of Medicine, Atlanta, GA 30322, USA
- Winship Cancer Institute, Emory University, Atlanta, GA 30322, USA
- Department of Pediatrics, Emory University, Atlanta, GA 30322, USA
- Aflac Cancer and Blood Disorders Center, Children’s Healthcare of Atlanta, Atlanta, GA 30322, USA
| | - Ian B. Copland
- Department of Hematology and Oncology, Emory University School of Medicine, Atlanta, GA 30322, USA
- Winship Cancer Institute, Emory University, Atlanta, GA 30322, USA
- Corresponding author
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189
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Heureaux J, Chen D, Murray VL, Deng CX, Liu AP. Activation of a bacterial mechanosensitive channel in mammalian cells by cytoskeletal stress. Cell Mol Bioeng 2014; 7:307-319. [PMID: 25606062 DOI: 10.1007/s12195-014-0337-8] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Cells can sense a myriad of mechanical stimuli. Mechanosensitive channel of large conductance (MscL) found in bacteria is a well-characterized mechanosensitive channel that rapidly responds to an increase in turgor pressure. Functional expression of MscL in mammalian cells has recently been demonstrated, revealing that molecular delivery or transport can be achieved by charge-induced activation of MscL. Despite a well-accepted mechanism for MscL activation by membrane tension in bacteria, it is not clear whether and how MscL can be opened by other modes of force transduction in mammalian cells. In this work, we used a variety of techniques to characterize the gating of MscL expressed in mammalian cells, using both wild type and a G22S mutant which activates at a lower threshold. In particular, employing a new technique, acoustic tweezing cytometry (ATC), we show that ultrasound actuation of integrin-bound microbubbles can lead to MscL opening and that ATC induced MscL activation was dependent on the functional linkage of the microbubbles with an intact actin cytoskeleton. Our results indicate that localized mechanical stress can mediate opening of MscL that requires force transduction through the actin cytoskeleton, revealing a new mode of MscL activation that may prove to be a useful tool for mechanobiology and drug delivery research.
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Affiliation(s)
- Johanna Heureaux
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Di Chen
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Victoria L Murray
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Cheri X Deng
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Allen P Liu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America ; Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America ; Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan, United States of America ; Biophysics Program, University of Michigan, Ann Arbor, Michigan, United States of America
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190
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Meinel A, Tränkle B, Römer W, Rohrbach A. Induced phagocytic particle uptake into a giant unilamellar vesicle. SOFT MATTER 2014; 10:3667-78. [PMID: 24676395 DOI: 10.1039/c3sm52964a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Phagocytosis, the uptake and ingestion of solid particles into living cells, is a central mechanism of our immune system. Due to the complexity of the uptake mechanism, the different forces involved in this process are only partly understood. Therefore the usage of a giant unilamellar vesicle (GUV) as the simplest biomimetic model for a cell allows one to investigate the influence of the lipid membrane on the energetics of the uptake process. Here, a photonic force microscope (PFM) is used to approach an optically trapped 1 μm latex bead to an immobilized GUV to finally insert the particle into the GUV. By analysing the mean displacement and the position fluctuations of the trapped particle during the uptake process in 3D with nanometre precision, we are able to record force and energy profiles, as well as changes in the viscous drag and the stiffness. After observing a global followed by a local deformation of the GUV, we measured uptake energies of 2000 kT to 5500 kT and uptake forces of 4 pN to 16 pN for Egg-PC GUVs with sizes of 18-26 μm and varying membrane tension. The measured energy profiles, which are compared to a Helfrich energy model for local and global deformation, show good coincidence with the theoretical results. Our proof-of-principle study opens the door to a large number of similar experiments with GUVs containing more biochemical components and complexity. This bottom-up strategy should allow for a better understanding of the physics of phagocytosis.
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Affiliation(s)
- Andreas Meinel
- Department of Microsystems Engineering (IMTEK), University of Freiburg, 79110 Freiburg, Germany.
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191
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Lepzelter D, Zaman MH. Modeling persistence in mesenchymal cell motility using explicit fibers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:5506-5509. [PMID: 24800650 PMCID: PMC4334298 DOI: 10.1021/la404832t] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 04/28/2014] [Indexed: 06/03/2023]
Abstract
Cell motility is central to a variety of fundamental processes ranging from cancer metastasis to immune responses, but it is still poorly understood in realistic native environments. Previous theoretical work has tended to focus on intracellular mechanisms or on small pieces of interaction with the environment. In this article, we present a simulation which accounts for mesenchymal movement in a 3D environment with explicit collagen fibers and show that this representation highlights the importance of both the concentration and alignment of fibers. We show good agreement with experimental results regarding cell motility and persistence in 3D environments and predict a specific effect on average instantaneous cell speed and persistence. Importantly, we show that a significant part of persistence in 3D is directly dependent on the physical environment, instead of indirectly dependent on the environment through the biochemical feedback that occurs in cell motility. Thus, new models of motility in three dimensions will need to account for the effects of explicit individual fibers on cells. This model can also be used to analyze cellular persistence in both mesenchymal and nonmesenchymal motility in complex three-dimensional environments to provide insights into mechanisms of cell motion seen in various cancer cell types in vivo.
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192
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Pfreundschuh M, Alsteens D, Hilbert M, Steinmetz MO, Müller DJ. Localizing chemical groups while imaging single native proteins by high-resolution atomic force microscopy. NANO LETTERS 2014; 14:2957-2964. [PMID: 24766578 DOI: 10.1021/nl5012905] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Simultaneous high-resolution imaging and localization of chemical interaction sites on single native proteins is a pertinent biophysical, biochemical, and nanotechnological challenge. Such structural mapping and characterization of binding sites is of importance in understanding how proteins interact with their environment and in manipulating such interactions in a plethora of biotechnological applications. Thus far, this challenge remains to be tackled. Here, we introduce force-distance curve-based atomic force microscopy (FD-based AFM) for the high-resolution imaging of SAS-6, a protein that self-assembles into cartwheel-like structures. Using functionalized AFM tips bearing Ni(2+)-N-nitrilotriacetate groups, we locate specific interaction sites on SAS-6 at nanometer resolution and quantify the binding strength of the Ni(2+)-NTA groups to histidine residues. The FD-based AFM approach can readily be applied to image any other native protein and to locate and structurally map histidine residues. Moreover, the surface chemistry used to functionalize the AFM tip can be modified to map other chemical interaction sites.
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Affiliation(s)
- Moritz Pfreundschuh
- Department of Biosystems Science and Engineering, ETH Zurich , Mattenstrasse 26, 4058 Basel, Switzerland
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193
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Lamprecht C, Hinterdorfer P, Ebner A. Applications of biosensing atomic force microscopy in monitoring drug and nanoparticle delivery. Expert Opin Drug Deliv 2014; 11:1237-53. [PMID: 24809228 DOI: 10.1517/17425247.2014.917078] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
INTRODUCTION The therapeutic effects of medicinal drugs not only depend on their properties, but also on effective transport to the target receptor. Here we highlight recent developments in this discipline and show applications of atomic force microscopy (AFM) that enable us to track the effects of drugs and the effectiveness of nanoparticle delivery at the single molecule level. AREAS COVERED Physiological AFM imaging enables visualization of topographical changes to cells as a result of drug exposure and allows observation of cellular responses that yield morphological changes. When we upgrade the regular measuring tip to a molecular biosensor, it enables investigation of functional changes at the molecular level via single molecule force spectroscopy. EXPERT OPINION Biosensing AFM techniques have generated powerful tools to monitor drug delivery in (living) cells. While technical developments in actual AFM methods have simplified measurements at relevant physiological conditions, understanding both the biological and technical background is still a crucial factor. However, due to its potential impact, we expect the number of application-based biosensing AFM techniques to further increase in the near future.
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Affiliation(s)
- Constanze Lamprecht
- University of Kiel, Institute of Materials Science Biocompatible Nanomaterials , Kaiserstr.2, 24143 Kiel , Germany
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194
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Transduction channels' gating can control friction on vibrating hair-cell bundles in the ear. Proc Natl Acad Sci U S A 2014; 111:7185-90. [PMID: 24799674 DOI: 10.1073/pnas.1402556111] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Hearing starts when sound-evoked mechanical vibrations of the hair-cell bundle activate mechanosensitive ion channels, giving birth to an electrical signal. As for any mechanical system, friction impedes movements of the hair bundle and thus constrains the sensitivity and frequency selectivity of auditory transduction. Friction is generally thought to result mainly from viscous drag by the surrounding fluid. We demonstrate here that the opening and closing of the transduction channels produce internal frictional forces that can dominate viscous drag on the micrometer-sized hair bundle. We characterized friction by analyzing hysteresis in the force-displacement relation of single hair-cell bundles in response to periodic triangular stimuli. For bundle velocities high enough to outrun adaptation, we found that frictional forces were maximal within the narrow region of deflections that elicited significant channel gating, plummeted upon application of a channel blocker, and displayed a sublinear growth for increasing bundle velocity. At low velocity, the slope of the relation between the frictional force and velocity was nearly fivefold larger than the hydrodynamic friction coefficient that was measured when the transduction machinery was decoupled from bundle motion by severing tip links. A theoretical analysis reveals that channel friction arises from coupling the dynamics of the conformational change associated with channel gating to tip-link tension. Varying channel properties affects friction, with faster channels producing smaller friction. We propose that this intrinsic source of friction may contribute to the process that sets the hair cell's characteristic frequency of responsiveness.
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195
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Paturej J, Dubbeldam JLA, Rostiashvili VG, Milchev A, Vilgis TA. Force spectroscopy of polymer desorption: theory and molecular dynamics simulations. SOFT MATTER 2014; 10:2785-2799. [PMID: 24667897 DOI: 10.1039/c3sm52618f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Forced detachment of a single polymer chain, strongly adsorbed on a solid substrate, is investigated by two complementary methods: a coarse-grained analytical dynamical model, based on the Onsager stochastic equation, and Molecular Dynamics (MD) simulations with a Langevin thermostat. The suggested approach makes it possible to go beyond the limitations of the conventional Bell-Evans model. We observe a series of characteristic force spikes when the pulling force is measured against the cantilever displacement during detachment at constant velocity vc (displacement control mode) and find that the average magnitude of this force increases as vc increases. The probability distributions of the pulling force and the end-monomer distance from the surface at the moment of the final detachment are investigated for different adsorption energies ε and pulling velocities vc. Our extensive MD simulations validate and support the main theoretical findings. Moreover, the simulations reveal a novel behavior: for a strong-friction and massive cantilever the force spike pattern is smeared out at large vc. As a challenging task for experimental bio-polymer sequencing in future we suggest the fabrication of a stiff, super-light, nanometer-sized AFM probe.
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Affiliation(s)
- Jarosław Paturej
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA.
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196
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Sharma AK, Shtylla B, Chowdhury D. Distribution of lifetimes of kinetochore–microtubule attachments: interplay of energy landscape, molecular motors and microtubule (de-)polymerization. Phys Biol 2014; 11:036004. [DOI: 10.1088/1478-3975/11/3/036004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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197
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Cao Z, Stevens MJ, Dobrynin AV. Adhesion and Wetting of Nanoparticles on Soft Surfaces. Macromolecules 2014. [DOI: 10.1021/ma500317q] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Zhen Cao
- Polymer
Program, Institute of Materials Science and Department of Physics, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Mark J. Stevens
- Center
for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, New Mexico 87185-1315, United States
| | - Andrey V. Dobrynin
- Polymer
Program, Institute of Materials Science and Department of Physics, University of Connecticut, Storrs, Connecticut 06269, United States
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198
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Gardinier JD, Gangadharan V, Wang L, Duncan RL. Hydraulic Pressure during Fluid Flow Regulates Purinergic Signaling and Cytoskeleton Organization of Osteoblasts. Cell Mol Bioeng 2014; 7:266-277. [PMID: 24910719 DOI: 10.1007/s12195-014-0329-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
During physiological activities, osteoblasts experience a variety of mechanical forces that stimulate anabolic responses at the cellular level necessary for the formation of new bone. Previous studies have primarily investigated the osteoblastic response to individual forms of mechanical stimuli. However in this study, we evaluated the response of osteoblasts to two simultaneous, but independently controlled stimuli; fluid flow-induced shear stress (FSS) and static or cyclic hydrostatic pressure (SHP or CHP, respectively). MC3T3-E1 osteoblasts-like cells were subjected to 12dyn/cm2 FSS along with SHP or CHP of varying magnitudes to determine if pressure enhances the anabolic response of osteoblasts during FSS. For both SHP and CHP, the magnitude of hydraulic pressure that induced the greatest release of ATP during FSS was 15 mmHg. Increasing the hydraulic pressure to 50 mmHg or 100 mmHg during FSS attenuated the ATP release compared to 15 mmHg during FSS. Decreasing the magnitude of pressure during FSS to atmospheric pressure reduced ATP release to that of basal ATP release from static cells and inhibited actin reorganization into stress fibers that normally occurred during FSS with 15 mmHg of pressure. In contrast, translocation of nuclear factor kappa B (NFκB) to the nucleus was independent of the magnitude of hydraulic pressure and was found to be mediated through the activation of phospholipase-C (PLC), but not src kinase. In conclusion, hydraulic pressure during FSS was found to regulate purinergic signaling and actin cytoskeleton reorganization in the osteoblasts in a biphasic manner, while FSS alone appeared to stimulate NFκB translocation. Understanding the effects of hydraulic pressure on the anabolic responses of osteoblasts during FSS may provide much needed insights into the physiologic effects of coupled mechanical stimuli on osteogenesis.
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Affiliation(s)
- Joseph D Gardinier
- Biomechanics and Movement Science, University of Delaware, Newark, DE, 19716 ; Department of Biological and Materials Science, University of Michigan, Ann Arbor, MI 48109
| | | | - Liyun Wang
- Biomechanics and Movement Science, University of Delaware, Newark, DE, 19716 ; Department of Mechanical Engineering, University of Delaware, Newark, DE, 19716
| | - Randall L Duncan
- Biomechanics and Movement Science, University of Delaware, Newark, DE, 19716 ; Department of Mechanical Engineering, University of Delaware, Newark, DE, 19716 ; Biological Sciences, University of Delaware, Newark, DE, 19716
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199
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Fichtner D, Lorenz B, Engin S, Deichmann C, Oelkers M, Janshoff A, Menke A, Wedlich D, Franz CM. Covalent and density-controlled surface immobilization of E-cadherin for adhesion force spectroscopy. PLoS One 2014; 9:e93123. [PMID: 24675966 PMCID: PMC3968077 DOI: 10.1371/journal.pone.0093123] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 03/02/2014] [Indexed: 11/18/2022] Open
Abstract
E-cadherin is a key cell-cell adhesion molecule but the impact of receptor density and the precise contribution of individual cadherin ectodomains in promoting cell adhesion are only incompletely understood. Investigating these mechanisms would benefit from artificial adhesion substrates carrying different cadherin ectodomains at defined surface density. We therefore developed a quantitative E-cadherin surface immobilization protocol based on the SNAP-tag technique. Extracellular (EC) fragments of E-cadherin fused to the SNAP-tag were covalently bound to self-assembled monolayers (SAM) of thiols carrying benzylguanine (BG) head groups. The adhesive functionality of the different E-cadherin surfaces was then assessed using cell spreading assays and single-cell (SCSF) and single-molecule (SMSF) force spectroscopy. We demonstrate that an E-cadherin construct containing only the first and second outmost EC domain (E1-2) is not sufficient for mediating cell adhesion and yields only low single cadherin-cadherin adhesion forces. In contrast, a construct containing all five EC domains (E1-5) efficiently promotes cell spreading and generates strong single cadherin and cell adhesion forces. By varying the concentration of BG head groups within the SAM we determined a lateral distance of 5–11 nm for optimal E-cadherin functionality. Integrating the results from SCMS and SMSF experiments furthermore demonstrated that the dissolution of E-cadherin adhesion contacts involves a sequential unbinding of individual cadherin receptors rather than the sudden rupture of larger cadherin receptor clusters. Our method of covalent, oriented and density-controlled E-cadherin immobilization thus provides a novel and versatile platform to study molecular mechanisms underlying cadherin-mediated cell adhesion under defined experimental conditions.
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Affiliation(s)
- Dagmar Fichtner
- Karlsruhe Institute of Technology (KIT), DFG-Center for Functional Nanostructures, Karlsruhe, Germany
| | - Bärbel Lorenz
- University of Göttingen, Institute of Physical Chemistry, Göttingen, Germany
| | - Sinem Engin
- Karlsruhe Institute of Technology (KIT), DFG-Center for Functional Nanostructures, Karlsruhe, Germany
| | - Christina Deichmann
- Karlsruhe Institute of Technology (KIT), DFG-Center for Functional Nanostructures, Karlsruhe, Germany
| | - Marieelen Oelkers
- University of Göttingen, Institute of Physical Chemistry, Göttingen, Germany
| | - Andreas Janshoff
- University of Göttingen, Institute of Physical Chemistry, Göttingen, Germany
| | - Andre Menke
- Justus-Liebig-University Gieβen, Molecular Oncology of Solid Tumors, Gieβen, Germany
| | - Doris Wedlich
- Karlsruhe Institute of Technology (KIT), DFG-Center for Functional Nanostructures, Karlsruhe, Germany
| | - Clemens M. Franz
- Karlsruhe Institute of Technology (KIT), DFG-Center for Functional Nanostructures, Karlsruhe, Germany
- * E-mail:
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Barry AK, Tabdili H, Muhamed I, Wu J, Shashikanth N, Gomez GA, Yap AS, Gottardi CJ, de Rooij J, Wang N, Leckband DE. α-catenin cytomechanics--role in cadherin-dependent adhesion and mechanotransduction. J Cell Sci 2014; 127:1779-91. [PMID: 24522187 DOI: 10.1242/jcs.139014] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The findings presented here demonstrate the role of α-catenin in cadherin-based adhesion and mechanotransduction in different mechanical contexts. Bead-twisting measurements in conjunction with imaging, and the use of different cell lines and α-catenin mutants reveal that the acute local mechanical manipulation of cadherin bonds triggers vinculin and actin recruitment to cadherin adhesions in an actin- and α-catenin-dependent manner. The modest effect of α-catenin on the two-dimensional binding affinities of cell surface cadherins further suggests that force-activated adhesion strengthening is due to enhanced cadherin-cytoskeletal interactions rather than to α-catenin-dependent affinity modulation. Complementary investigations of cadherin-based rigidity sensing also suggest that, although α-catenin alters traction force generation, it is not the sole regulator of cell contractility on compliant cadherin-coated substrata.
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Affiliation(s)
- Adrienne K Barry
- Department of Biochemistry, University of Illinois, Urbana, IL 61801-3709, USA
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