1
|
Li L, Wang S, Han K, Qi X, Ma S, Li L, Yin J, Li D, Li X, Qian J. Quantifying Shear-induced Margination and Adhesion of Platelets in Microvascular Blood Flow. J Mol Biol 2023; 435:167824. [PMID: 36108775 DOI: 10.1016/j.jmb.2022.167824] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 09/04/2022] [Accepted: 09/06/2022] [Indexed: 02/04/2023]
Abstract
Platelet margination and adhesion are two critical and closely related steps in thrombus formation. Using dissipative particle dynamics (DPD) method that seamlessly models blood cells, blood plasma, and vessel walls with functionalized surfaces, we quantify the shear-induced margination and adhesion of platelets in microvascular blood flow. The results show that the occurrence of shear-induced RBC-platelet collisions has a remarkable influence on the degree of platelet margination. We characterize the lateral motion of individual platelets by a mean square displacement analysis of platelet trajectories, and find that the wall-induced lift force and the shear-induced displacement in wall-bounded flow cause the variation in near-wall platelet distribution. We then investigate the platelet adhesive dynamics under different flow conditions, by conducting DPD simulations of blood flow in a microtube with fibrinogen-coated wall surfaces. We find that the platelet adhesion is enhanced with the increase of fibrinogen concentration level but decreased with the increase of shear rate. These results are consistent with available experimental results. In addition, we demonstrate that the adherent platelets have a negative impact on the margination dynamics of the circulating platelets, which is mainly due to the climbing effect induced by the adherent ones. Taken together, these findings provide useful insights into the platelet margination and adhesion dynamics, which may facilitate the understanding of the predominant processes governing the initial stage of thrombus formation.
Collapse
Affiliation(s)
- Lujuan Li
- State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou, China; Department of Engineering Mechanics, Zhejiang University, Hangzhou, China
| | - Shuo Wang
- State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou, China; Department of Engineering Mechanics, Zhejiang University, Hangzhou, China
| | - Keqin Han
- State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou, China; Department of Engineering Mechanics, Zhejiang University, Hangzhou, China
| | - Xiaojing Qi
- State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou, China; Department of Engineering Mechanics, Zhejiang University, Hangzhou, China
| | - Shuhao Ma
- State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou, China; Department of Engineering Mechanics, Zhejiang University, Hangzhou, China
| | - Li Li
- Department of Endocrinology and Metabolism, Ningbo First Hospital, Ningbo, China
| | - Jun Yin
- State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou, China; School of Mechanical Engineering, Zhejiang University, Hangzhou, China
| | - Dechang Li
- State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou, China; Department of Engineering Mechanics, Zhejiang University, Hangzhou, China.
| | - Xuejin Li
- State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou, China; Department of Engineering Mechanics, Zhejiang University, Hangzhou, China; The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China.
| | - Jin Qian
- State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou, China; Department of Engineering Mechanics, Zhejiang University, Hangzhou, China.
| |
Collapse
|
2
|
Zhang Z, Ahmed D. Light-driven high-precision cell adhesion kinetics. LIGHT, SCIENCE & APPLICATIONS 2022; 11:266. [PMID: 36100594 PMCID: PMC9470670 DOI: 10.1038/s41377-022-00963-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Existing single-cell adhesion kinetics methods are performed under conditions highly unlike the physiological cell adhesion conditions. Now, researchers have developed a new optical technique for high-precision measurement of cell lateral adhesion kinetics in complex clinical samples.
Collapse
Affiliation(s)
- Zhiyuan Zhang
- Acoustic Robotics Systems Laboratory, Institute of Robotics and Intelligent Systems, Department of Mechanical and Process Engineering, ETH Zurich, Säumerstrasse 4, CH-8803, Zurich, Switzerland
| | - Daniel Ahmed
- Acoustic Robotics Systems Laboratory, Institute of Robotics and Intelligent Systems, Department of Mechanical and Process Engineering, ETH Zurich, Säumerstrasse 4, CH-8803, Zurich, Switzerland.
| |
Collapse
|
3
|
Light-driven single-cell rotational adhesion frequency assay. ELIGHT 2022; 2:13. [PMID: 35965781 PMCID: PMC9358104 DOI: 10.1186/s43593-022-00020-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 06/28/2022] [Accepted: 07/07/2022] [Indexed: 01/13/2023]
Abstract
The interaction between cell surface receptors and extracellular ligands is highly related to many physiological processes in living systems. Many techniques have been developed to measure the ligand-receptor binding kinetics at the single-cell level. However, few techniques can measure the physiologically relevant shear binding affinity over a single cell in the clinical environment. Here, we develop a new optical technique, termed single-cell rotational adhesion frequency assay (scRAFA), that mimics in vivo cell adhesion to achieve label-free determination of both homogeneous and heterogeneous binding kinetics of targeted cells at the subcellular level. Moreover, the scRAFA is also applicable to analyze the binding affinities on a single cell in native human biofluids. With its superior performance and general applicability, scRAFA is expected to find applications in study of the spatial organization of cell surface receptors and diagnosis of infectious diseases.
Collapse
|
4
|
Liu Y, Ding H, Li J, Lou X, Yang M, Zheng Y. Light-driven single-cell rotational adhesion frequency assay. ELIGHT 2022; 2:13. [PMID: 35965781 DOI: 10.1186/s43593-022-00013-3] [Citation(s) in RCA: 56] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 06/28/2022] [Accepted: 07/07/2022] [Indexed: 05/23/2023]
Abstract
UNLABELLED The interaction between cell surface receptors and extracellular ligands is highly related to many physiological processes in living systems. Many techniques have been developed to measure the ligand-receptor binding kinetics at the single-cell level. However, few techniques can measure the physiologically relevant shear binding affinity over a single cell in the clinical environment. Here, we develop a new optical technique, termed single-cell rotational adhesion frequency assay (scRAFA), that mimics in vivo cell adhesion to achieve label-free determination of both homogeneous and heterogeneous binding kinetics of targeted cells at the subcellular level. Moreover, the scRAFA is also applicable to analyze the binding affinities on a single cell in native human biofluids. With its superior performance and general applicability, scRAFA is expected to find applications in study of the spatial organization of cell surface receptors and diagnosis of infectious diseases. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1186/s43593-022-00020-4.
Collapse
Affiliation(s)
- Yaoran Liu
- Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX 78712 USA
| | - Hongru Ding
- Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX 78712 USA
| | - Jingang Li
- Materials Science & Engineering Program and Texas Materials Institute, The University of Texas at Austin, Austin, TX 78712 USA
| | - Xin Lou
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Mingcheng Yang
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049 China
- Beijing National Laboratory for Condensed Matter Physics and Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190 China
- Songshan Lake Materials Laboratory, Dongguan, 523808 Guangdong China
| | - Yuebing Zheng
- Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX 78712 USA
- Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX 78712 USA
- Materials Science & Engineering Program and Texas Materials Institute, The University of Texas at Austin, Austin, TX 78712 USA
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712 USA
| |
Collapse
|
5
|
Dam T, Chouliara M, Junghans V, Jönsson P. Supported Lipid Bilayers and the Study of Two-Dimensional Binding Kinetics. Front Mol Biosci 2022; 9:833123. [PMID: 35252352 PMCID: PMC8896763 DOI: 10.3389/fmolb.2022.833123] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 01/27/2022] [Indexed: 11/13/2022] Open
Abstract
Binding between protein molecules on contacting cells is essential in initiating and regulating several key biological processes. In contrast to interactions between molecules in solution, these events are restricted to the two-dimensional (2D) plane of the meeting cell surfaces. However, converting between the more commonly available binding kinetics measured in solution and the so-called 2D binding kinetics has proven a complicated task since for the latter several factors other than the protein-protein interaction per se have an impact. A few important examples of these are: protein density, membrane fluctuations, force on the bond and the use of auxiliary binding molecules. The development of model membranes, and in particular supported lipid bilayers (SLBs), has made it possible to simplify the studied contact to analyze these effects and to measure 2D binding kinetics of individual protein-protein interactions. We will in this review give an overview of, and discuss, how different SLB systems have been used for this and compare different methods to measure binding kinetics in cell-SLB contacts. Typically, the SLB is functionalized with fluorescently labelled ligands whose interaction with the corresponding receptor on a binding cell can be detected. This interaction can either be studied 1) by an accumulation of ligands in the cell-SLB contact, whose magnitude depends on the density of the proteins and binding affinity of the interaction, or 2) by tracking single ligands in the SLB, which upon interaction with a receptor result in a change of motion of the diffusing ligand. The advantages and disadvantages of other methods measuring 2D binding kinetics will also be discussed and compared to the fluorescence-based methods. Although binding kinetic measurements in cell-SLB contacts have provided novel information on how ligands interact with receptors in vivo the number of these measurements is still limited. This is influenced by the complexity of the system as well as the required experimental time. Moreover, the outcome can vary significantly between studies, highlighting the necessity for continued development of methods to study 2D binding kinetics with higher precision and ease.
Collapse
Affiliation(s)
- Tommy Dam
- Department of Chemistry, Lund University, Lund, Sweden
| | | | - Victoria Junghans
- Nuffield Department of Medicine, CAMS Oxford Institute, University of Oxford, Oxford, United Kingdom
| | - Peter Jönsson
- Department of Chemistry, Lund University, Lund, Sweden
- *Correspondence: Peter Jönsson,
| |
Collapse
|
6
|
Yasunaga AB, Li ITS. Quantification of fast molecular adhesion by fluorescence footprinting. SCIENCE ADVANCES 2021; 7:7/34/eabe6984. [PMID: 34407937 PMCID: PMC8373131 DOI: 10.1126/sciadv.abe6984] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 06/29/2021] [Indexed: 05/07/2023]
Abstract
Rolling adhesion is a unique process in which the adhesion events are short-lived and operate under highly nonequilibrium conditions. These characteristics pose a challenge in molecular force quantification, where in situ measurement of these forces cannot be achieved with molecular force sensors that probe near equilibrium. Here, we demonstrated a quantitative adhesion footprint assay combining DNA-based nonequilibrium force probes and modeling to measure the molecular force involved in fast rolling adhesion. We were able to directly profile the ensemble molecular force distribution in our system during rolling adhesion with a dynamic range between 0 and 18 pN. Our results showed that the shear stress driving bead rolling motility directly controls the molecular tension on the probe-conjugated adhesion complex. Furthermore, the shear stress can steer the dissociation bias of components within the molecular force probe complex, favoring either DNA probe dissociation or receptor-ligand dissociation.
Collapse
Affiliation(s)
- Adam B Yasunaga
- Department of Chemistry, Biochemistry and Molecular Biology, The University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Isaac T S Li
- Department of Chemistry, Biochemistry and Molecular Biology, The University of British Columbia Okanagan, Kelowna, BC, Canada.
| |
Collapse
|
7
|
Li D, Wang Q, Xu C, Cheng Y, Zhang YW, Ji B. How Does Nature Evade the "Larger is Weaker" Fate of Ultralong Silk β-Sheet Nanocrystallites. NANO LETTERS 2020; 20:8516-8523. [PMID: 33054228 DOI: 10.1021/acs.nanolett.0c02968] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Silk protein builds up one of the strongest fibers superior to most synthetic and natural polymers. However, the strengthening mechanisms of the silk proteins remain largely elusive because of their complex nanocomposite structures. Here, we report an unusual behavior of this kind of material that is distinctively different from those of metals and other polymers. We find that there are multiple interface microcracks nucleating and stacking under the shear loading, dividing the interchain interface into small segments, by which the silk protein can achieve a high strength even with the ultralong chains. This is a new strategy of microstructure design of soft matter that could avoid the "larger is weaker" fate due to the increase of the chain length. This novel mechanism is crucial for building strong polymer materials with long chain molecules and at the same time retaining their complex functional and structural properties.
Collapse
Affiliation(s)
- Dechang Li
- Department of Engineering Mechanics, Zhejiang University, Hangzhou 310027, China
- Department of Applied Mechanics, Beijing Institute of Technology, Beijing 100081, China
| | - Qianchun Wang
- Department of Applied Mechanics, Beijing Institute of Technology, Beijing 100081, China
| | - Changjian Xu
- Department of Applied Mechanics, Beijing Institute of Technology, Beijing 100081, China
| | - Yuan Cheng
- Institute of High Performance Computing, Agency for Science Technology and Research (A*STAR), 1 Fusionopolis Way, Singapore 138632, Singapore
| | - Yong-Wei Zhang
- Institute of High Performance Computing, Agency for Science Technology and Research (A*STAR), 1 Fusionopolis Way, Singapore 138632, Singapore
| | - Baohua Ji
- Department of Engineering Mechanics, Zhejiang University, Hangzhou 310027, China
- Department of Applied Mechanics, Beijing Institute of Technology, Beijing 100081, China
| |
Collapse
|
8
|
Li L, Kang W, Wang J. Mechanical Model for Catch-Bond-Mediated Cell Adhesion in Shear Flow. Int J Mol Sci 2020; 21:ijms21020584. [PMID: 31963253 PMCID: PMC7013535 DOI: 10.3390/ijms21020584] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 01/13/2020] [Indexed: 12/31/2022] Open
Abstract
Catch bond, whose lifetime increases with applied tensile force, can often mediate rolling adhesion of cells in a hydrodynamic environment. However, the mechanical mechanism governing the kinetics of rolling adhesion of cells through catch-bond under shear flow is not yet clear. In this study, a mechanical model is proposed for catch-bond-mediated cell adhesion in shear flow. The stochastic reaction of bond formation and dissociation is described as a Markovian process, whereas the dynamic motion of cells follows classical analytical mechanics. The steady state of cells significantly depends on the shear rate of flow. The upper and lower critical shear rates required for cell detachment and attachment are extracted, respectively. When the shear rate increases from the lower threshold to the upper threshold, cell rolling became slower and more regular, implying the flow-enhanced adhesion phenomenon. Our results suggest that this flow-enhanced stability of rolling adhesion is attributed to the competition between stochastic reactions of bonds and dynamics of cell rolling, instead of force lengthening the lifetime of catch bonds, thereby challenging the current view in understanding the mechanism behind this flow-enhanced adhesion phenomenon. Moreover, the loading history of flow defining bistability of cell adhesion in shear flow is predicted. These theoretical predictions are verified by Monte Carlo simulations and are related to the experimental observations reported in literature.
Collapse
Affiliation(s)
- Long Li
- Key Laboratory of Mechanics on Disaster and Environment in Western China, Ministry of Education, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou 730000, China;
- PULS Group, Institute for Theoretical Physics, FAU Erlangen-Nürnberg, 91058 Erlangen, Germany
- Correspondence: (L.L.); (J.W.)
| | - Wei Kang
- Key Laboratory of Mechanics on Disaster and Environment in Western China, Ministry of Education, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou 730000, China;
| | - Jizeng Wang
- Key Laboratory of Mechanics on Disaster and Environment in Western China, Ministry of Education, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou 730000, China;
- Correspondence: (L.L.); (J.W.)
| |
Collapse
|
9
|
Bellino L, Florio G, Puglisi G. The influence of device handles in single-molecule experiments. SOFT MATTER 2019; 15:8680-8690. [PMID: 31621748 DOI: 10.1039/c9sm01376h] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We deduce a fully analytical model to predict the artifacts of the device handles in single molecule force spectroscopy experiments. As we show, neglecting the handle stiffness can lead to crucial overestimation or underestimation of the stability properties and unfolding thresholds of multistable molecules.
Collapse
Affiliation(s)
- Luca Bellino
- Politecnico di Bari, (DMMM) Dipartimento di Meccanica, Matematica e Management, Politecnico di Bari, Via Re David 200, 70125, Italy.
| | - Giuseppe Florio
- Politecnico di Bari, (DMMM) Dipartimento di Meccanica, Matematica e Management, Politecnico di Bari, Via Re David 200, 70125, Italy. and INFN, Sezione di Bari, I-70126, Italy
| | - Giuseppe Puglisi
- Politecnico di Bari, (DICAR) Dipartimento di Scienza dell'Ingegneria Civile e dell'Architettura, Politecnico di Bari, Via Re David 200, 70126, Italy.
| |
Collapse
|
10
|
Li D, Ji B. Protein conformational transitions coupling with ligand interactions: Simulations from molecules to medicine. MEDICINE IN NOVEL TECHNOLOGY AND DEVICES 2019. [DOI: 10.1016/j.medntd.2019.100026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
|
11
|
Unveiling the influence of device stiffness in single macromolecule unfolding. Sci Rep 2019; 9:4997. [PMID: 30899032 PMCID: PMC6428835 DOI: 10.1038/s41598-019-41330-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 03/01/2019] [Indexed: 11/23/2022] Open
Abstract
Single-molecule stretching experiments on DNA, RNA, and other biological macromolecules opened up the possibility of an impressive progress in many fields of life and medical sciences. The reliability of such experiments may be crucially limited by the possibility of determining the influence of the apparatus on the experimental outputs. Here we deduce a model that let us analytically evaluate such influence, fundamental for the interpretation of Single Molecule Force Spectroscopy experiments and intermolecular interactions phenomena. As we show, our model is coherent with previous numerical results and quantitively reproduce AFM experimental tests on titin macromolecules and P-selectin with variable probe stiffnesses.
Collapse
|
12
|
Li N, Yang H, Wang M, Lü S, Zhang Y, Long M. Ligand-specific binding forces of LFA-1 and Mac-1 in neutrophil adhesion and crawling. Mol Biol Cell 2017; 29:408-418. [PMID: 29282280 PMCID: PMC6014170 DOI: 10.1091/mbc.e16-12-0827] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 12/15/2017] [Accepted: 12/15/2017] [Indexed: 12/12/2022] Open
Abstract
The force spectra for various LFA-1/Mac-1–ligand bonds were compared and their functions tested in mediating PMN recruitment under flow. Multiple endothelial ligands present distinct bond rupture forces and lifetimes, which correlate well with their biological phenotypes. In addition to ICAM, JAM or RAGE is also crucial in cell adhesion and crawling. Lymphocyte function–associated antigen-1 (LFA-1) and macrophage-1 antigen (Mac-1) and their counterreceptors such as intercellular cell adhesion molecules (ICAM-1 and ICAM-2), junctional adhesion molecules (JAM-A, JAM-C), and receptors for advanced glycation end products (RAGE) are crucial for promoting polymorphonuclear leukocyte (neutrophil, PMN) recruitment. The underlying mechanisms of ligand-specific bindings in this cascade remain incompletely known. We compared the dynamic force spectra for various LFA-1/Mac-1–ligand bonds using single-molecule atomic force microscopy (AFM) and tested their functions in mediating PMN recruitment under in vitro shear flow. Distinct features of bond rupture forces and lifetimes were uncovered for these ligands, implying their diverse roles in regulating PMN adhesion on endothelium. LFA-1 dominates PMN adhesion on ICAM-1 and ICAM-2, while Mac-1 mediates PMN adhesion on RAGE, JAM-A, and JAM-C, which is consistent with their bond strength. All ligands can trigger PMN spreading and polarization, in which Mac-1 seems to induce outside-in signaling more effectively. LFA-1–ICAM-1 and LFA-1/Mac-1–JAM-C bonds can accelerate PMN crawling under high shear stress, presumably due to their high mechanical strength. This work provides new insight into basic molecular mechanisms of physiological ligands of β2 integrins in PMN recruitment.
Collapse
Affiliation(s)
- Ning Li
- Center of Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory), and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China.,School of Engineering Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.,Key Laboratory of Biorheological Science and Technology, Chongqing University, Ministry of Education, Chongqing 400044, China
| | - Hao Yang
- Center of Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory), and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China.,School of Engineering Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Manliu Wang
- Center of Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory), and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China.,School of Engineering Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shouqin Lü
- Center of Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory), and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China.,School of Engineering Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yan Zhang
- Center of Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory), and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China.,School of Engineering Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Mian Long
- Center of Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory), and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China .,School of Engineering Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| |
Collapse
|
13
|
Zhao X, Liu Y, Guo Z, Zhang Y, Li Y, Liu W. Mechanical response and deformation mechanics of Type IV pili investigated using steered coarse-grained molecular dynamics simulation. J Biomech 2017; 56:97-101. [PMID: 28365063 DOI: 10.1016/j.jbiomech.2017.03.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 03/09/2017] [Accepted: 03/11/2017] [Indexed: 12/20/2022]
Abstract
Type IV pili are long filamentous structures on the surface of bacteria, which can be rapidly assembled or disassembled with pilin subunits by molecular motors. They can generate force during retraction and are involved in many bacterial functions. Steered molecular dynamics simulations with coarse-grained MARTINI models are carried out to investigate the mechanical behaviors of pili under tension. Our study is the first to report a Young's modulus of 0.80±0.07GPa and a spring constant of 1294.6±116.5kJmol-1nm-2 for pilus. Our results show the mechanical responses of pili are different from those described by the worm-like chain model and the van der Waal's interactions play a critical role in the mechanical responses. Moreover, the effects of pulling rates and virtual spring constants of pilus on Young's modulus are studied and two distinct morphological stages with the conformational changes appear during the extension of pilus are observed. This work provide insight into the mechanics and the deformation mechanism of pilus assembly.
Collapse
Affiliation(s)
- Xiaoxi Zhao
- School of Water Conservancy and Environmental Engineering, Zhengzhou University, Zhengzhou 450001, China; Department of Modern Mechanics, University of Science and Technology of China, Hefei 230026, China
| | - Yankai Liu
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China
| | - Zhouhang Guo
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China
| | - Yizhe Zhang
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China
| | - Yongchi Li
- Department of Modern Mechanics, University of Science and Technology of China, Hefei 230026, China
| | - Wei Liu
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China.
| |
Collapse
|
14
|
Gupta VK. Effects of cellular viscoelasticity in lifetime extraction of single receptor-ligand bonds. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 91:062701. [PMID: 26172730 DOI: 10.1103/physreve.91.062701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Indexed: 05/15/2023]
Abstract
Single-molecule force spectroscopy is widely used to determine kinetic parameters of dissociation by analyzing bond rupture data obtained via applying mechanical force to cells, capsules, and beads that are attached to an intermolecular bond. The bond rupture data are obtained in experiments either at a constant force or at a constant loading rate. We explore the effect of cellular viscoelasticity in constant-force experiments. Specifically, we perform Monte Carlo simulations of bond rupture at a given constant force to obtain the bond lifetime as a function of force in the absence and in the presence of bond force modulation due to cellular viscoelasticity, to explore its effect on the bond lifetime.
Collapse
Affiliation(s)
- V K Gupta
- Colorado State University, Fort Collins, Colorado 80523, USA
| |
Collapse
|
15
|
Lü S, Chen S, Mao D, Zhang Y, Long M. Contribution of the CR domain to P-selectin lectin domain allostery by regulating the orientation of the EGF domain. PLoS One 2015; 10:e0118083. [PMID: 25675100 PMCID: PMC4326174 DOI: 10.1371/journal.pone.0118083] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2014] [Accepted: 01/04/2015] [Indexed: 12/01/2022] Open
Abstract
The allostery of P-selectin has been studied extensively with a focus on the Lec and EGF domains, whereas the contribution of the CR domain remains unclear. Here, molecular dynamics simulations (MDS) combined with homology modeling were preformed to investigate the impact of the CR domain on P-selectin allostery. The results indicated that the CR domain plays a role in the allosteric dynamics of P-selectin in two ways. First, the CR1 domain tends to stabilize the low affinity of P-selectin during the equilibration processes with the transition inhibition from the S1 to S1’ state by restraining the extension of the bent EGF orientation, or with the relaxation acceleration of the S2 state by promoting the bending of the extended EGF orientation. Second, the existence of CR domain increases intramolecular extension prior to complex separation, increasing the time available for the allosteric shift during forced dissociation with a prolonged bond duration. These findings further our understanding of the structure-function relationship of P-selectin with the enriched micro-structural bases of the CR domain.
Collapse
Affiliation(s)
- Shouqin Lü
- Key Laboratory of Microgravity (National Microgravity Laboratory), Institute of Mechanics, Chinese Academy of Sciences, Beijing, China
- Center of Biomechanics and Bioengineering, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China
- Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China
- * E-mail: (SQL); (ML)
| | - Shenbao Chen
- Key Laboratory of Microgravity (National Microgravity Laboratory), Institute of Mechanics, Chinese Academy of Sciences, Beijing, China
- Center of Biomechanics and Bioengineering, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China
- Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China
| | - Debin Mao
- Key Laboratory of Microgravity (National Microgravity Laboratory), Institute of Mechanics, Chinese Academy of Sciences, Beijing, China
- Center of Biomechanics and Bioengineering, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China
- Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China
| | - Yan Zhang
- Key Laboratory of Microgravity (National Microgravity Laboratory), Institute of Mechanics, Chinese Academy of Sciences, Beijing, China
- Center of Biomechanics and Bioengineering, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China
- Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China
| | - Mian Long
- Key Laboratory of Microgravity (National Microgravity Laboratory), Institute of Mechanics, Chinese Academy of Sciences, Beijing, China
- Center of Biomechanics and Bioengineering, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China
- Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China
- * E-mail: (SQL); (ML)
| |
Collapse
|
16
|
Gupta VK. Effects of cellular viscoelasticity in multiple-bond force spectroscopy. Biomech Model Mechanobiol 2014; 14:615-32. [PMID: 25326875 DOI: 10.1007/s10237-014-0626-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 10/04/2014] [Indexed: 12/17/2022]
Abstract
Receptor-ligand bonds are often subjected to forces that regulate their detachment via modulating off-rates. Though the dynamics of detachment is primarily controlled by the physical chemistry of adhesion molecules cellular features such as cell deformability and microvillus viscoelasticity have been shown to have an effect on it as well. In this work, Monte Carlo simulation of the rupture of multiple receptor-ligand bonds between substrate and a polymorphonuclear leukocyte (PMN) cell suspended in a Newtonian fluid is performed. It is demonstrated via various micromechanical models of the PMN cell adhered to the substrate by multiple receptor-ligand bonds that viscous drag caused by relative motion of cell suspended in a Newtonian fluid and cellular viscoelasticity modulate transmission of an applied external load to receptor-ligand bonds. It is demonstrated that due to cellular viscoelasticity the instantaneous intermolecular bond force is lower than the instantaneous applied force. It is also demonstrated that due to cellular viscoelasticity, the mean intermolecular bond rupture forces are lowered while the mean bond lifetime increases.
Collapse
Affiliation(s)
- V K Gupta
- Department of Mechanical Engineering, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD, 21250, USA,
| |
Collapse
|
17
|
Gupta VK. Stochastic simulation of single-molecule pulling experiments. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2014; 37:99. [PMID: 25348662 DOI: 10.1140/epje/i2014-14099-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 10/03/2014] [Accepted: 10/08/2014] [Indexed: 06/04/2023]
Abstract
Single-molecule pulling experiments are widely used for studying the structure, dynamics, and function of single biological molecules via applying mechanical forces on them in a controlled way. Pulling at a constant speed or at a constant force builds up a mechanical force on a molecule or molecular complex leading to a molecular transition such as the dissociation of a molecular complex, unfolding of a protein, or unwrapping of a higher-order structure. We perform Brownian dynamics and Monte Carlo simulations of single-molecule pulling experiments. Through our simulations we demonstrate that the molecular transition rate based on the Kramers theory in the high-barrier limit becomes unsuitable as the applied force approaches the critical force at which the barrier disappears. We also demonstrate that use of molecular transition rate based on mean first passage time (MFPT) approach would be more relevant in describing molecular transition especially as the applied force approaches the critical force.
Collapse
Affiliation(s)
- V K Gupta
- Colorado State University, 80523, Fort Collins, Colorado, USA,
| |
Collapse
|
18
|
Wang J, Lü D, Mao D, Long M. Mechanomics: an emerging field between biology and biomechanics. Protein Cell 2014; 5:518-31. [PMID: 24756566 PMCID: PMC4085284 DOI: 10.1007/s13238-014-0057-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 03/10/2014] [Indexed: 12/31/2022] Open
Abstract
Cells sense various in vivo mechanical stimuli, which initiate downstream signaling to mechanical forces. While a body of evidences is presented on the impact of limited mechanical regulators in past decades, the mechanisms how biomechanical responses globally affect cell function need to be addressed. Complexity and diversity of in vivo mechanical clues present distinct patterns of shear flow, tensile stretch, or mechanical compression with various parametric combination of its magnitude, duration, or frequency. Thus, it is required to understand, from the viewpoint of mechanobiology, what mechanical features of cells are, why mechanical properties are different among distinct cell types, and how forces are transduced to downstream biochemical signals. Meanwhile, those in vitro isolated mechanical stimuli are usually coupled together in vivo, suggesting that the different factors that are in effect individually could be canceled out or orchestrated with each other. Evidently, omics analysis, a powerful tool in the field of system biology, is advantageous to combine with mechanobiology and then to map the full-set of mechanically sensitive proteins and transcripts encoded by its genome. This new emerging field, namely mechanomics, makes it possible to elucidate the global responses under systematically-varied mechanical stimuli. This review discusses the current advances in the related fields of mechanomics and elaborates how cells sense external forces and activate the biological responses.
Collapse
Affiliation(s)
- Jiawen Wang
- Center for Biomechanics and Bioengineering and Key Laboratory of Microgravity, Institute of Mechanics, Chinese Academy of Sciences, Beijing, 100190, China
| | | | | | | |
Collapse
|
19
|
Li D, Ji B. Predicted rupture force of a single molecular bond becomes rate independent at ultralow loading rates. PHYSICAL REVIEW LETTERS 2014; 112:078302. [PMID: 24579639 DOI: 10.1103/physrevlett.112.078302] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2013] [Indexed: 05/15/2023]
Abstract
We present for the first time a theoretical model of studying the saturation of the rupture force of a single molecular bond that causes the rupture force to be rate independent under an ultralow loading rate. This saturation will obviously bring challenges to understanding the rupture behavior of the molecular bond using conventional methods. This intriguing feature implies that the molecular bond has a nonzero strength at a vanishing loading rate. We find that the saturation behavior is caused by bond rebinding when the loading rate is lower than a limiting value depending on the loading stiffness.
Collapse
Affiliation(s)
- Dechang Li
- Biomechanics and Biomaterials Laboratory, Department of Applied Mechanics, Beijing Institute of Technology, Beijing 100081, China
| | - Baohua Ji
- Biomechanics and Biomaterials Laboratory, Department of Applied Mechanics, Beijing Institute of Technology, Beijing 100081, China
| |
Collapse
|
20
|
Li N, Mao D, Lü S, Tong C, Zhang Y, Long M. Distinct binding affinities of Mac-1 and LFA-1 in neutrophil activation. THE JOURNAL OF IMMUNOLOGY 2013; 190:4371-81. [PMID: 23514737 DOI: 10.4049/jimmunol.1201374] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Macrophage-1 Ag (Mac-1) and lymphocyte function-associated Ag-1 (LFA-1), two β2 integrins expressed on neutrophils (PMNs), mediate PMN recruitment cascade by binding to intercellular adhesive molecule 1. Distinct functions of LFA-1-initiating PMN slow rolling and firm adhesion but Mac-1-mediating cell crawling are assumed to be governed by the differences in their binding affinities and kinetic rates. In this study, we applied an adhesion frequency approach to compare their kinetics in the quiescent and activated states using three molecular systems, constitutively expressed receptors on PMNs, wild-type and high-affinity (HA) full-length constructs transfected on 293T cells, and wild-type and HA recombinant extracellular constructs. Data indicate that the difference in binding affinity between Mac-1 and LFA-1 is on-rate dominated with slightly or moderately varied off-rate. This finding was further confirmed when both β2 integrins were activated by chemokines (fMLF or IL-8), divalent cations (Mg(2+) or Mn(2+)), or disulfide bond lockage on an HA state. Structural analyses reveal that such the kinetics difference is likely attributed to the distinct conformations at the interface of Mac-1 or LFA-1 and intercellular adhesive molecule 1. This work furthers the understandings in the kinetic differences between Mac-1 and LFA-1 and in their biological correlations with molecular activation and structural bases.
Collapse
Affiliation(s)
- Ning Li
- Key Laboratory of Microgravity (National Microgravity Laboratory) and Center of Biomechanics and Bioengineering, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
| | | | | | | | | | | |
Collapse
|
21
|
Xiao B, Tong C, Jia X, Guo R, Lü S, Zhang Y, McEver RP, Zhu C, Long M. Tyrosine replacement of PSGL-1 reduces association kinetics with P- and L-selectin on the cell membrane. Biophys J 2013; 103:777-85. [PMID: 22947939 DOI: 10.1016/j.bpj.2012.07.028] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 07/16/2012] [Accepted: 07/18/2012] [Indexed: 10/28/2022] Open
Abstract
Binding of selectins to P-selectin glycoprotein ligand-1 (PSGL-1) mediates tethering and rolling of leukocytes on the endothelium during inflammation. Previous measurements obtained with a flow-chamber assay have shown that mutations of three tyrosines at the PSGL-1 N-terminus (Y46, Y48, and Y51) increase the reverse rates and their sensitivity to the force of bonds with P- and L-selectin. However, the effects of these mutations on the binding affinities and forward rates have not been studied. We quantified these effects by using an adhesion frequency assay to measure two-dimensional affinity and kinetic rates at zero force. Wild-type PSGL-1 has 2.2- to 8.5-fold higher binding affinities for P- and L-selectin than PSGL-1 mutants with two of three tyrosines substituted by phenylalanines, and 9.6- to 49-fold higher affinities than the PSGL-1 mutant with all three tyrosines replaced. In descending order, the affinity decreased from wild-type to Y48/51F, Y46/51F, Y46/48F, and Y46/48/51F. The affinity differences were attributed to major changes in the forward rate and minor changes in the reverse rate, suggesting that these tyrosines regulate the accessibility of PSGL-1 to P- and L-selectin via electrostatic interactions, which is supported by molecular-dynamics simulations. Our results provide insights into the structure-function relationship of receptor-ligand binding at a single-residue level.
Collapse
Affiliation(s)
- Botao Xiao
- Key Laboratory of Microgravity, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China
| | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Gupta VK. Rupture of single receptor-ligand bonds: a new insight into probability distribution function. Colloids Surf B Biointerfaces 2013; 101:501-9. [PMID: 23010061 DOI: 10.1016/j.colsurfb.2012.07.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Revised: 07/11/2012] [Accepted: 07/16/2012] [Indexed: 11/18/2022]
Abstract
Single molecule force spectroscopy is widely used to determine kinetic parameters of dissociation by analyzing bond rupture data obtained via applying mechanical force to cells, capsules, and beads that are attached to an intermolecular bond. The current analysis assumes that the intermolecular bond force is equal to the externally applied mechanical force. We confirm that viscous drag alone or in combination with cellular deformation resulting in viscoelasticity modulates bond force so that the instantaneous intermolecular bond force is not equivalent to the applied force. The bond force modulation leads to bond rupture time and force histograms that differ from those predicted by probability distribution function (PDF) using the current approach. A new methodology that accounts for bond force modulation in obtaining PDF is presented. The predicted histograms from the new methodology are in excellent agreement with the respective histograms obtained from Monte Carlo simulation.
Collapse
Affiliation(s)
- V K Gupta
- University of Maryland Baltimore County, Baltimore, MD 21250, USA.
| |
Collapse
|
23
|
Effect of viscoelasticity on the analysis of single-molecule force spectroscopy on live cells. Biophys J 2012; 103:137-45. [PMID: 22828340 DOI: 10.1016/j.bpj.2012.05.044] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Revised: 04/30/2012] [Accepted: 05/24/2012] [Indexed: 10/28/2022] Open
Abstract
Single-molecule force spectroscopy is used to probe the kinetics of receptor-ligand bonds by applying mechanical forces to an intermediate media on which the molecules reside. When this intermediate media is a live cell, the viscoelastic properties can affect the calculation of rate constants. We theoretically investigate the effect of media viscoelasticity on the common assumption that the bond force is equal to the instantaneous applied force. Dynamic force spectroscopy is simulated between two cells of varying micromechanical properties adhered by a single bond with a constant kinetic off-rate. We show that cell and microvilli deformation, and hydrodynamic drag contribute to bond forces that can be 28-90% lower than the applied force for loading rates of 10(3)-10(7) pN/s, resulting in longer bond lifetimes. These longer bond lifetimes are not caused by changes in bond kinetics; rather, they are due to the mechanical response of the intermediate media on which the bonds reside. Under the assumption that the instantaneous bond force is equal to the applied force--thereby ignoring viscoelasticity--leads to 14-39% error in the determination of off-rates. We present an approach that incorporates viscoelastic properties in calculating the instantaneous bond force and kinetic dissociation parameter of the intermolecular bond.
Collapse
|
24
|
Gupta VK. Effect of viscous drag on multiple receptor-ligand bonds rupture force. Colloids Surf B Biointerfaces 2012; 100:229-39. [PMID: 22766301 PMCID: PMC3404210 DOI: 10.1016/j.colsurfb.2012.05.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 04/20/2012] [Accepted: 05/23/2012] [Indexed: 11/21/2022]
Abstract
Monte Carlo simulation of the rupture of multiple receptor-ligand bonds between two PMN cells suspended in a Newtonian fluid is performed. We demonstrate via micro-mechanical model of two cells adhered by multiple receptor-ligand bonds that viscous drag caused by relative motion of cell suspended in a Newtonian fluid modulates transmission of an applied external load to bonds. Specifically, it is demonstrated that at any time the intermolecular bond force is not equivalent to the instantaneous applied force. The difference in the instantaneous applied force and the intermolecular bond force depends on the viscosity of fluid, the size of cell, the applied loading rate, and the number of bonds at any instant of time. Viscous drag acting on cell reduces average bond rupture forces.
Collapse
Affiliation(s)
- V K Gupta
- University of Maryland Baltimore County, Baltimore, MD 21250, USA.
| |
Collapse
|
25
|
Gupta VK, Eggleton CD. A theoretical method to determine unstressed off-rate from multiple bond force spectroscopy. Colloids Surf B Biointerfaces 2012; 95:50-6. [PMID: 22417406 PMCID: PMC3348403 DOI: 10.1016/j.colsurfb.2012.02.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Revised: 02/07/2012] [Accepted: 02/08/2012] [Indexed: 12/24/2022]
Abstract
Using dynamic force spectroscopy to measure the kinetic off-rates of intermolecular bonds currently requires the isolation of single molecules. This requirement arises in part because no tractable analytic method for determining kinetic off-rates from the rupture of a large number of bonds under dynamic forces is currently available. We introduce a novel method for determining the unstressed off-rate from dynamic force spectroscopy experiments involving a large number of bonds. Using both the Bell and Dembo models we show that the unstressed off-rate calculated using the proposed method is in good agreement with the prescribed unstressed off-rate used in Monte-Carlo simulations of multiple bond dynamic force spectroscopy experiments given initial number of bonds (50-500) and loading rate 10(3)-10(6)pN/s.
Collapse
Affiliation(s)
- V K Gupta
- University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | | |
Collapse
|
26
|
Sarangapani KK, Qian J, Chen W, Zarnitsyna VI, Mehta P, Yago T, McEver RP, Zhu C. Regulation of catch bonds by rate of force application. J Biol Chem 2011; 286:32749-61. [PMID: 21775439 DOI: 10.1074/jbc.m111.240044] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The current paradigm for receptor-ligand dissociation kinetics assumes off-rates as functions of instantaneous force without impact from its prior history. This a priori assumption is the foundation for predicting dissociation from a given initial state using kinetic equations. Here we have invalidated this assumption by demonstrating the impact of force history with single-bond kinetic experiments involving selectins and their ligands that mediate leukocyte tethering and rolling on vascular surfaces during inflammation. Dissociation of bonds between L-selectin and P-selectin glycoprotein ligand-1 (PSGL-1) loaded at a constant ramp rate to a constant hold force behaved as catch-slip bonds at low ramp rates that transformed to slip-only bonds at high ramp rates. Strikingly, bonds between L-selectin and 6-sulfo-sialyl Lewis X were impervious to ramp rate changes. This ligand-specific force history effect resembled the effect of a point mutation at the L-selectin surface (L-selectinA108H) predicted to contact the former but not the latter ligand, suggesting that the high ramp rate induced similar structural changes as the mutation. Although the A108H substitution in L-selectin eliminated the ramp rate responsiveness of its dissociation from PSGL-1, the inverse mutation H108A in P-selectin acquired the ramp rate responsiveness. Our data are well explained by the sliding-rebinding model for catch-slip bonds extended to incorporate the additional force history dependence, with Ala-108 playing a pivotal role in this structural mechanism. These results call for a paradigm shift in modeling the mechanical regulation of receptor-ligand bond dissociation, which includes conformational coupling between binding pocket and remote regions of the interacting molecules.
Collapse
Affiliation(s)
- Krishna K Sarangapani
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | | | | | | | | | | | | | | |
Collapse
|
27
|
Gupta VK, Eggleton CD. Effect of cell and microvillus mechanics on the transmission of applied loads to single bonds in dynamic force spectroscopy. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 84:011912. [PMID: 21867218 DOI: 10.1103/physreve.84.011912] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Revised: 02/14/2011] [Indexed: 05/31/2023]
Abstract
Receptor-ligand interactions that mediate cellular adhesion are often subjected to forces that regulate their detachment via modulating off-rates. Although the dynamics of detachment is primarily controlled by the physical chemistry of adhesion molecules, cellular features such as cell deformability and microvillus viscoelasticity have been shown to affect the rolling velocity of leukocytes in vitro through experiments and simulation. In this work, we demonstrate via various micromechanical models of two cells adhered by a single (intramolecular) bond that cell deformability and microvillus viscoelasticity modulate transmission of an applied external load to an intramolecular bond, and thus the dynamics of detachment. Specifically, it is demonstrated that the intermolecular bond force is not equivalent to the instantaneous applied force and that the instantaneous bond force decreases with cellular and microvillus compliance. As cellular compliance increases, not only does the time lag between the applied load and the bond force increase, an initial response time is observed during which cell deformation is observed without transfer of force to the bond. It is further demonstrated that following tether formation the instantaneous intramoleular bond force increases linearly at a rate dependent on microvillus viscosity. Monte Carlo simulations with fixed kinetic parameters predict that both cell and microvillus compliance increase the average rupture time, although the average rupture force based on bond length remains nearly unchanged.
Collapse
Affiliation(s)
- V K Gupta
- University of Maryland Baltimore County, Baltimore, Maryland 21250, USA
| | | |
Collapse
|
28
|
Abstract
Protein-protein interactions are the basis of both biochemical and biophysical signaling of living cells. In many cases, the receptor is present on the cell surface while the ligand is in solution or linked to another support (extracellular matrix or another cell). In the case of cellular adhesion, forces are continuously applied to receptor-ligand complexes and, as a consequence, the dissociation kinetics of the bonds may change. It is, thus, relevant to study the kinetics of protein-protein interactions in response to applied forces, as this is the most physiologically relevant situation. The atomic force microscope (AFM) was one of the first nanotools to be applied to this end. However, new approaches need to be developed to better understand the complex energy landscape of molecular interactions under applied stress. In this chapter, we described the use of the AFM to carry out force-clamp measurements on receptor-ligand bonds. Force-clamp measurements on bonds consist of applying a constant and controlled force to a receptor-ligand bond and measure the resulting dissociation lifetime. The described methods include the required materials, functionalization of tips and substrates, force-clamping measurements, and processing and interpretation of the results. An illustrative example is given with the well-studied streptavidin-biotin complex.
Collapse
Affiliation(s)
- Félix Rico
- Miller School of Medicine, University of Miami, Miami, FL, USA
| | | | | |
Collapse
|
29
|
Rico F, Chu C, Abdulreda MH, Qin Y, Moy VT. Temperature modulation of integrin-mediated cell adhesion. Biophys J 2010; 99:1387-96. [PMID: 20816050 PMCID: PMC2931747 DOI: 10.1016/j.bpj.2010.06.037] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2010] [Revised: 06/02/2010] [Accepted: 06/14/2010] [Indexed: 10/19/2022] Open
Abstract
In response to external stimuli, cells modulate their adhesive state by regulating the number and intrinsic affinity of receptor/ligand bonds. A number of studies have shown that cell adhesion is dramatically reduced at room or lower temperatures as compared with physiological temperature. However, the underlying mechanism that modulates adhesion is still unclear. Here, we investigated the adhesion of the monocytic cell line THP-1 to a surface coated with intercellular adhesion molecule-1 (ICAM-1) as a function of temperature. THP-1 cells express the integrin lymphocyte function-associated antigen-1 (LFA-1), a receptor for ICAM-1. Direct force measurements of cell adhesion and cell elasticity were carried out by atomic force microscopy. Force measurements revealed an increase of the work of de-adhesion with temperature that was coupled to a gradual decrease in cellular stiffness. Of interest, single-molecule measurements revealed that the rupture force of the LFA-1/ICAM-1 complex decreased with temperature. A detailed analysis of the force curves indicated that temperature-modulated cell adhesion was mainly due to the enhanced ability of cells to deform and to form a greater number of longer membrane tethers at physiological temperatures. Together, these results emphasize the importance of cell mechanics and membrane-cytoskeleton interaction on the modulation of cell adhesion.
Collapse
Affiliation(s)
- Félix Rico
- Department of Physiology and Biophysics, University of Miami, Miller School of Medicine, Miami, Florida, USA.
| | | | | | | | | |
Collapse
|
30
|
Gefen A. Effects of Virus Size and Cell Stiffness on Forces, Work, and Pressures Driving Membrane Invagination in a Receptor-Mediated Endocytosis. J Biomech Eng 2010; 132:084501. [DOI: 10.1115/1.4001888] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A continuum model based on the contact mechanics theory was developed and used for evaluating virus indentation forces at the early stage of membrane invagination, as well as the work of the virus indentation forces and virus-cell contact pressures in a receptor-mediated endocytosis, depending on the virus size and virus/cell stiffnesses. The model indicated that early virus indentation forces are in the order of 1–10 pN and for a given extent of virus engulfment, they increase linearly with the elastic modulus of the host cell and also with the square of the virus radius. The work of invagination at the initial phase of virus endocytosis is in the order of tens of zeptojoules and peak virus-cell contact pressures at this stage are in the order of hundreds of Pascals to several kPa. For a given extent of virus engulfment, peak and average contact pressures increase linearly with the elastic modulus of the host cell but interestingly, they are negligibly affected by the virus size. The present model may be useful in the fields of cellular biomechanics, virology and nanodrug delivery to evaluate mechanical factors during the early phase of membrane invagination.
Collapse
Affiliation(s)
- Amit Gefen
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel
| |
Collapse
|
31
|
Wang D, Xie Y, Yuan B, Xu J, Gong P, Jiang X. A stretching device for imaging real-time molecular dynamics of live cells adhering to elastic membranes on inverted microscopes during the entire process of the stretch. Integr Biol (Camb) 2010; 2:288-93. [DOI: 10.1039/b920644b] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
32
|
Paik DH, Seol Y, Halsey WA, Perkins TT. Integrating a high-force optical trap with gold nanoposts and a robust gold-DNA bond. NANO LETTERS 2009; 9:2978-2983. [PMID: 19492836 DOI: 10.1021/nl901404s] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Gold-thiol chemistry is widely used in nanotechnology but has not been exploited in optical-trapping experiments due to laser-induced ablation of gold. We circumvented this problem by using an array of gold nanoposts (r = 50-250 nm, h approximately 20 nm) that allowed for quantitative optical-trapping assays without direct irradiation of the gold. DNA was covalently attached to the gold via dithiol phosphoramidite (DTPA). By using three DTPAs, the gold-DNA bond was not cleaved in the presence of excess thiolated compounds. This chemical robustness allowed us to reduce nonspecific sticking by passivating the unreacted gold with methoxy-(polyethylene glycol)-thiol. We routinely achieved single beads anchored to the nanoposts by single DNA molecules. We measured DNA's elasticity and its overstretching transition, demonstrating moderate- and high-force optical-trapping assays using gold-thiol chemistry. Force spectroscopy measurements were consistent with the rupture of the strepavidin-biotin bond between the bead and the DNA. This implied that the DNA remained anchored to the surface due to the strong gold-thiol bond. Consistent with this conclusion, we repeatedly reattached the trapped bead to the same individual DNA molecule. Thus, surface conjugation of biomolecules onto an array of gold nanostructures by chemically and mechanically robust bonds provides a unique way to carry out spatially controlled, repeatable measurements of single molecules.
Collapse
Affiliation(s)
- D Hern Paik
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309, USA
| | | | | | | |
Collapse
|
33
|
Sun G, Zhang Y, Huo B, Long M. Surface-bound selectin-ligand binding is regulated by carrier diffusion. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2009; 38:701-11. [PMID: 19274458 DOI: 10.1007/s00249-009-0428-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2008] [Revised: 02/06/2009] [Accepted: 02/15/2009] [Indexed: 11/26/2022]
Abstract
Two-dimensional (2D) kinetics of receptor-ligand interactions governs cell adhesion in many biological processes. While the dissociation kinetics of receptor-ligand bond is extensively investigated, the association kinetics has much less been quantified. Recently receptor-ligand interactions between two surfaces were investigated using a thermal fluctuation assay upon biomembrane force probe technique (Chen et al. in Biophys J 94:694-701, 2008). The regulating factors on association kinetics, however, are not well characterized. Here we developed an alternative thermal fluctuation assay using optical trap technique, which enables to visualize consecutive binding-unbinding transition and to quantify the impact of microbead diffusion on receptor-ligand binding. Three selectin constructs (sLs, sPs, and PLE) and their ligand P-selectin glycoprotein ligand 1 were used to conduct the measurements. It was indicated that bond formation was reduced by enhancing the diffusivity of selectin-coupled carrier, suggesting that carrier diffusion is crucial to determine receptor-ligand binding. It was also found that 2D forward rate predicted upon first-order kinetics was in the order of sPs > sLs > PLE and bond formation was history-dependent. These results further the understandings in regulating association kinetics of surface-bound receptor-ligand interactions.
Collapse
Affiliation(s)
- Ganyun Sun
- National Microgravity Laboratory and Center for Biomechanics and Bioengineering, Institute of Mechanics, Chinese Academy of Sciences, Beijing, PR China
| | | | | | | |
Collapse
|