1
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Sengupta K, Dillard P, Limozin L. Morphodynamics of T-lymphocytes: Scanning to spreading. Biophys J 2024; 123:2224-2233. [PMID: 38425041 PMCID: PMC11331044 DOI: 10.1016/j.bpj.2024.02.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 01/29/2024] [Accepted: 02/26/2024] [Indexed: 03/02/2024] Open
Abstract
Binding of the T cell receptor complex to its ligand, the subsequent molecular rearrangement, and the concomitant cell-scale shape changes represent the very first steps of adaptive immune recognition. The first minutes of the interaction of T cells and antigen presenting cells have been extensively scrutinized; yet, gaps remain in our understanding of how the biophysical properties of the environment may impact the sequence of events. In particular, many pioneering experiments were done on immobilized ligands and gave major insights into the process of T cell activation, whereas later experiments have indicated that ligand mobility was of paramount importance, especially to enable the formation of T cell receptor clusters. Systematic experiments to compare and reconcile the two schools are still lacking. Furthermore, recent investigations using compliant substrates have elucidated other intriguing aspects of T cell mechanics. Here we review experiments on interaction of T cells with planar artificial antigen presenting cells to explore the impact of mechanics on adhesion and actin morphodynamics during the spreading process. We enumerate a sequence tracing first contact to final spread state that is consistent with current understanding. Finally, we interpret the presented experimental results in light of a mechanical model that captures all the different morphodynamic states.
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Affiliation(s)
- Kheya Sengupta
- Aix-Marseille Université, CNRS, CINAM, Turing Centre for Living Systems, Marseille, France.
| | - Pierre Dillard
- Aix-Marseille Université, CNRS, CINAM, Turing Centre for Living Systems, Marseille, France; Aix-Marseille Université, CNRS, INSERM, LAI, Turing Centre for Living Systems, Marseille, France
| | - Laurent Limozin
- Aix-Marseille Université, CNRS, INSERM, LAI, Turing Centre for Living Systems, Marseille, France.
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2
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Nieves DJ, Pandzic E, Gunasinghe SD, Goyette J, Owen DM, Justin Gooding J, Gaus K. The T cell receptor displays lateral signal propagation involving non-engaged receptors. NANOSCALE 2022; 14:3513-3526. [PMID: 35171177 DOI: 10.1039/d1nr05855j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
T cells are highly sensitive to low levels of antigen, but how this sensitivity is achieved is currently unknown. Here, we imaged proximal TCR-CD3 signal propagation with single molecule localization microscopy (SMLM) in T cells activated with nanoscale clusters of TCR stimuli. We observed the formation of large TCR-CD3 clusters that exceeded the area of the ligand clusters, and required multivalent interactions facilitated by TCR-CD3 phosphorylation for assembly. Within these clustered TCR-CD3 domains, TCR-CD3 signaling spread laterally for ∼500 nm, far beyond the activating site, via non-engaged receptors. Local receptor density determined the functional cooperativity between engaged and non-engaged receptors, but lateral signal propagation was not influenced by the genetic deletion of ZAP70. Taken together, our data demonstrates that clustered ligands induced the clustering of non-ligated TCR-CD3 into domains that cooperatively facilitate lateral signal propagation.
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Affiliation(s)
- Daniel J Nieves
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences and the ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney, Australia
- Institute of Immunology and Immunotherapy, School of Mathematics, and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK.
| | - Elvis Pandzic
- Katharina Gaus Light Microscopy Facility, Mark Wainwright Analytical Centre, University of New South Wales, Sydney, Australia
| | - Sachith D Gunasinghe
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences and the ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney, Australia
| | - Jesse Goyette
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences and the ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney, Australia
| | - Dylan M Owen
- Institute of Immunology and Immunotherapy, School of Mathematics, and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK.
| | - J Justin Gooding
- School of Chemistry and Australian Centre for NanoMedicine, University of New South Wales, Sydney, Australia
| | - Katharina Gaus
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences and the ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney, Australia
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3
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Nassereddine A, Abdelrahman A, Benard E, Bedu F, Ozerov I, Limozin L, Sengupta K. Ligand Nanocluster Array Enables Artificial-Intelligence-Based Detection of Hidden Features in T-Cell Architecture. NANO LETTERS 2021; 21:5606-5613. [PMID: 34170136 DOI: 10.1021/acs.nanolett.1c01073] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Protein patterning has emerged as a powerful means to interrogate adhering cells. However, the tools to apply a sub-micrometer periodic stimulus and the analysis of the response are still being standardized. We propose a technique combining electron beam lithography and surface functionalization to fabricate nanopatterns compatible with advanced imaging. The repetitive pattern enables a deep-learning algorithm to reveal that T cells organize their membrane and actin network differently depending upon whether the ligands are clustered or homogeneously distributed, an effect invisible to the unassisted human eye even after extensive image analysis. This fabrication and analysis toolbox should be useful, both together and separately, for exploring general correlation between a spatially structured subcellular stimulation and a subtle cellular response.
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Affiliation(s)
- Aya Nassereddine
- Aix Marseille Univ, CNRS, CINAM, 13009 Marseille, France
- Aix Marseille Univ, CNRS, INSERM, LAI, Turing Centre for Living Systems, 13009 Marseille, France
| | - Ahmed Abdelrahman
- Aix Marseille Univ, CNRS, CINAM, 13009 Marseille, France
- Aix Marseille Univ, CNRS, INSERM, LAI, Turing Centre for Living Systems, 13009 Marseille, France
| | | | - Frederic Bedu
- Aix Marseille Univ, CNRS, CINAM, 13009 Marseille, France
| | - Igor Ozerov
- Aix Marseille Univ, CNRS, CINAM, 13009 Marseille, France
| | - Laurent Limozin
- Aix Marseille Univ, CNRS, INSERM, LAI, Turing Centre for Living Systems, 13009 Marseille, France
| | - Kheya Sengupta
- Aix Marseille Univ, CNRS, CINAM, 13009 Marseille, France
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4
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Li L, Stumpf BH, Smith AS. Molecular Biomechanics Controls Protein Mixing and Segregation in Adherent Membranes. Int J Mol Sci 2021; 22:3699. [PMID: 33918167 PMCID: PMC8037219 DOI: 10.3390/ijms22073699] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Revised: 03/22/2021] [Accepted: 03/25/2021] [Indexed: 01/28/2023] Open
Abstract
Cells interact with their environment by forming complex structures involving a multitude of proteins within assemblies in the plasma membrane. Despite the omnipresence of these assemblies, a number of questions about the correlations between the organisation of domains and the biomechanical properties of the involved proteins, namely their length, flexibility and affinity, as well as about the coupling to the elastic, fluctuating membrane, remain open. Here we address these issues by developing an effective Kinetic Monte Carlo simulation to model membrane adhesion. We apply this model to a typical experiment in which a cell binds to a functionalized solid supported bilayer and use two ligand-receptor pairs to study these couplings. We find that differences in affinity and length of proteins forming adhesive contacts result in several characteristic features in the calculated phase diagrams. One such feature is mixed states occurring even with proteins with length differences of 10 nm. Another feature are stable nanodomains with segregated proteins appearing on time scales of cell experiments, and for biologically relevant parameters. Furthermore, we show that macroscopic ring-like patterns can spontaneously form as a consequence of emergent protein fluxes. The capacity to form domains is captured by an order parameter that is founded on the virial coefficients for the membrane mediated interactions between bonds, which allow us to collapse all the data. These findings show that taking into account the role of the membrane allows us to recover a number of experimentally observed patterns. This is an important perspective in the context of explicit biological systems, which can now be studied in significant detail.
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Affiliation(s)
- Long Li
- PULS Group, Institute for Theoretical Physics and Interdisciplinary Center for Nanostructured Films, Friedrich-Alexander-University Erlangen-Nürnberg, Cauerstrasse 3, 91058 Erlangen, Germany; (L.L.); (B.H.S.)
- 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
| | - Bernd Henning Stumpf
- PULS Group, Institute for Theoretical Physics and Interdisciplinary Center for Nanostructured Films, Friedrich-Alexander-University Erlangen-Nürnberg, Cauerstrasse 3, 91058 Erlangen, Germany; (L.L.); (B.H.S.)
| | - Ana-Sunčana Smith
- PULS Group, Institute for Theoretical Physics and Interdisciplinary Center for Nanostructured Films, Friedrich-Alexander-University Erlangen-Nürnberg, Cauerstrasse 3, 91058 Erlangen, Germany; (L.L.); (B.H.S.)
- Group for Computational Life Sciences, Division of Physical Chemistry, Ruđer Bošković Institute, Bijenička cesta, 10000 Zagreb, Croatia
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5
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González C, Chames P, Kerfelec B, Baty D, Robert P, Limozin L. Nanobody-CD16 Catch Bond Reveals NK Cell Mechanosensitivity. Biophys J 2019; 116:1516-1526. [PMID: 30979550 PMCID: PMC6486492 DOI: 10.1016/j.bpj.2019.03.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 02/16/2019] [Accepted: 03/06/2019] [Indexed: 12/15/2022] Open
Abstract
Antibodies are key tools in biomedical research and medicine. Their binding properties are classically measured in solution and characterized by an affinity. However, in physiological conditions, antibodies can bridge an immune effector cell and an antigen-presenting cell, implying that mechanical forces may apply to the bonds. For example, in antibody-dependent cell cytotoxicity-a major mode of action of therapeutic monoclonal antibodies-the Fab domains bind the antigens on the target cell, whereas the Fc domain binds to the activating receptor CD16 (also known as FcgRIII) of an immune effector cell, in a quasi-bidimensional environment (2D). Therefore, there is a strong need to investigate antigen/antibody binding under force (2D) to better understand and predict antibody activity in vivo. We used two anti-CD16 nanobodies targeting two different epitopes and laminar flow chamber assay to measure the association and dissociation of single bonds formed between microsphere-bound CD16 antigens and surface-bound anti-CD16 nanobodies (or single-domain antibodies), simulating 2D encounters. The two nanobodies exhibit similar 2D association kinetics, characterized by a strong dependence on the molecular encounter duration. However, their 2D dissociation kinetics strongly differ as a function of applied force: one exhibits a slip bond behavior in which off rate increases with force, and the other exhibits a catch-bond behavior in which off rate decreases with force. This is the first time, to our knowledge, that catch-bond behavior was reported for antigen-antibody bond. Quantification of natural killer cells spreading on surfaces coated with the nanobodies provides a comparison between 2D and three-dimensional adhesion in a cellular context, supporting the hypothesis of natural killer cell mechanosensitivity. Our results may also have strong implications for the design of efficient bispecific antibodies for therapeutic applications.
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Affiliation(s)
- Cristina González
- Aix Marseille Univ, CNRS, INSERM, LAI, Laboratoire Adhesion et Inflammation, Marseille, France
| | - Patrick Chames
- Aix Marseille Univ, CNRS, INSERM, Institut Paoli-Calmettes, CRCM, Centre de Recherche en Cancérologie de Marseille, Marseille, France
| | - Brigitte Kerfelec
- Aix Marseille Univ, CNRS, INSERM, Institut Paoli-Calmettes, CRCM, Centre de Recherche en Cancérologie de Marseille, Marseille, France
| | - Daniel Baty
- Aix Marseille Univ, CNRS, INSERM, Institut Paoli-Calmettes, CRCM, Centre de Recherche en Cancérologie de Marseille, Marseille, France
| | - Philippe Robert
- Aix Marseille Univ, CNRS, INSERM, LAI, Laboratoire Adhesion et Inflammation, Marseille, France; Laboratoire d'Immunologie, Assistance Publique - Hôpitaux de Marseille, Marseille, France.
| | - Laurent Limozin
- Aix Marseille Univ, CNRS, INSERM, LAI, Laboratoire Adhesion et Inflammation, Marseille, France.
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Hortigüela V, Larrañaga E, Lagunas A, Acosta GA, Albericio F, Andilla J, Loza-Alvarez P, Martínez E. Large-Area Biomolecule Nanopatterns on Diblock Copolymer Surfaces for Cell Adhesion Studies. NANOMATERIALS (BASEL, SWITZERLAND) 2019; 9:E579. [PMID: 30970600 PMCID: PMC6523780 DOI: 10.3390/nano9040579] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 04/02/2019] [Accepted: 04/03/2019] [Indexed: 11/16/2022]
Abstract
Cell membrane receptors bind to extracellular ligands, triggering intracellular signal transduction pathways that result in specific cell function. Some receptors require to be associated forming clusters for effective signaling. Increasing evidences suggest that receptor clustering is subjected to spatially controlled ligand distribution at the nanoscale. Herein we present a method to produce in an easy, straightforward process, nanopatterns of biomolecular ligands to study ligand⁻receptor processes involving multivalent interactions. We based our platform in self-assembled diblock copolymers composed of poly(styrene) (PS) and poly(methyl methacrylate) (PMMA) that form PMMA nanodomains in a closed-packed hexagonal arrangement. Upon PMMA selective functionalization, biomolecular nanopatterns over large areas are produced. Nanopattern size and spacing can be controlled by the composition of the block-copolymer selected. Nanopatterns of cell adhesive peptides of different size and spacing were produced, and their impact in integrin receptor clustering and the formation of cell focal adhesions was studied. Cells on ligand nanopatterns showed an increased number of focal contacts, which were, in turn, more matured than those found in cells cultured on randomly presenting ligands. These findings suggest that our methodology is a suitable, versatile tool to study and control receptor clustering signaling and downstream cell behavior through a surface-based ligand patterning technique.
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Affiliation(s)
- Verónica Hortigüela
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), 08028 Barcelona, Spain.
| | - Enara Larrañaga
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), 08028 Barcelona, Spain.
| | - Anna Lagunas
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), 08028 Barcelona, Spain.
- Centro de Investigación Biomédica en Red (CIBER), 28029 Madrid, Spain.
| | - Gerardo A Acosta
- Centro de Investigación Biomédica en Red (CIBER), 28029 Madrid, Spain.
- Department of Organic Chemistry, University of Barcelona, 08028 Barcelona, Spain.
| | - Fernando Albericio
- Centro de Investigación Biomédica en Red (CIBER), 28029 Madrid, Spain.
- Department of Organic Chemistry, University of Barcelona, 08028 Barcelona, Spain.
| | - Jordi Andilla
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology (BIST), Castelldefels, 08860 Barcelona, Spain.
| | - Pablo Loza-Alvarez
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology (BIST), Castelldefels, 08860 Barcelona, Spain.
| | - Elena Martínez
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), 08028 Barcelona, Spain.
- Centro de Investigación Biomédica en Red (CIBER), 28029 Madrid, Spain.
- Department of Electronics and Biomedical Engineering, University of Barcelona, 08028 Barcelona, Spain.
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7
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Biphasic mechanosensitivity of T cell receptor-mediated spreading of lymphocytes. Proc Natl Acad Sci U S A 2019; 116:5908-5913. [PMID: 30850545 DOI: 10.1073/pnas.1811516116] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Mechanosensing by T cells through the T cell receptor (TCR) is at the heart of immune recognition. While the mechanobiology of the TCR at the molecular level is increasingly well documented, its link to cell-scale response is poorly understood. Here we explore T cell spreading response as a function of substrate rigidity and show that remarkably, depending on the surface receptors stimulated, the cellular response may be either biphasic or monotonous. When adhering solely via the TCR complex, T cells respond to environmental stiffness in an unusual fashion, attaining maximal spreading on an optimal substrate stiffness comparable to that of professional antigen-presenting cells. However, in the presence of additional ligands for the integrin LFA-1, this biphasic response is abrogated and the cell spreading increases monotonously with stiffness up to a saturation value. This ligand-specific mechanosensing is effected through an actin-polymerization-dependent mechanism. We construct a mesoscale semianalytical model based on force-dependent bond rupture and show that cell-scale biphasic or monotonous behavior emerges from molecular parameters. As the substrate stiffness is increased, there is a competition between increasing effective stiffness of the bonds, which leads to increased cell spreading and increasing bond breakage, which leads to decreased spreading. We hypothesize that the link between actin and the receptors (TCR or LFA-1), rather than the ligand/receptor linkage, is the site of this mechanosensing.
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8
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Benard E, Nunès JA, Limozin L, Sengupta K. T Cells on Engineered Substrates: The Impact of TCR Clustering Is Enhanced by LFA-1 Engagement. Front Immunol 2018; 9:2085. [PMID: 30279692 PMCID: PMC6154019 DOI: 10.3389/fimmu.2018.02085] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 08/23/2018] [Indexed: 12/15/2022] Open
Abstract
We created APC-mimetic synthetic substrates to study the impact of ligand clustering on T cell activation and spreading. The substrates exhibit antibodies directed against the TCR-complex in the form of a patterned array of sub micrometric dots surrounded by a fluid supported lipid bilayer (SLB) which may itself be functionalized with another bio-molecule. We show that for T cell adhesion mediated by T cell receptor (TCR) alone, in the patterned, but not in the corresponding homogeneous controls, the TCR, ZAP-70 and actin are present in the form of clusters or patches that co-localize with the ligand-dots. However, global cell scale parameters like cell area and actin distribution are only weakly impacted by ligand clustering. In presence of ICAM-1 - the ligand of the T cell integrin LFA-1 - on the SLB, the TCR is still clustered due to the patterning of its ligands, but now global parameters are also impacted. The actin organization changes to a peripheral ring, resembling the classical actin distribution seen on homogeneous substrates, the patterned membrane topography disappears and the membrane is flat, whereas the cell area increases significantly. These observations taken together point to a possible pivotal role for LFA-1 in amplifying the effect of TCR-clustering. No such effect is evident for co-engagement of CD28, affected via its ligand B7.2. Unlike on ICAM-1, on B7.2 cell spreading and actin organization are similar for homogeneous and patterned substrates. However, TCR and ZAP-70 clusters are still formed in the patterned case. These results indicate complementary role for LFA-1 and CD28 in the regulation and putative coupling of TCR micro-clusters to actin. The engineered substrates presented here clearly have the potential to act as platform for fundamental research in immune cell biology, as well as translational analyses in immunotherapy, for example to screen molecules for their role in T cell adhesion/activation.
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Affiliation(s)
| | - Jacques A Nunès
- CNRS, UMR7258, Centre de Recherche en Cancerologie de Marseille, Immunity and Cancer Team, Institut Paoli-Calmettes, Inserm, U1068, Aix-Marseille Université UM 105, Marseille, France
| | - Laurent Limozin
- LAI, CNRS UMR 7333, INSERM UMR 1067, Aix-Marseille Université, Marseille, France
| | - Kheya Sengupta
- CNRS, CINaM UMR 7325, Aix-Marseille Université, Marseille, France
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Bartelt SM, Chervyachkova E, Steinkühler J, Ricken J, Wieneke R, Tampé R, Dimova R, Wegner SV. Dynamic blue light-switchable protein patterns on giant unilamellar vesicles. Chem Commun (Camb) 2018; 54:948-951. [DOI: 10.1039/c7cc08758f] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The photoswitchable iLID/Nano interaction allows for specific, non-invasive, reversible and dynamic protein photopatterning on GUVs with high spatiotemporal control.
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Affiliation(s)
- S. M. Bartelt
- Max Planck Institute for Polymer Research
- Mainz
- Germany
| | | | - J. Steinkühler
- Department of Theory and Biosystems
- Max Planck Institute of Colloids and Interfaces
- Potsdam
- Germany
| | - J. Ricken
- Max Planck Institute for Polymer Research
- Mainz
- Germany
| | - R. Wieneke
- Institut für Biochemie, Biozentrum
- Cluster of Excellence Frankfurt
- Goethe-Universität Frankfurt
- Frankfurt
- Germany
| | - R. Tampé
- Institut für Biochemie, Biozentrum
- Cluster of Excellence Frankfurt
- Goethe-Universität Frankfurt
- Frankfurt
- Germany
| | - R. Dimova
- Department of Theory and Biosystems
- Max Planck Institute of Colloids and Interfaces
- Potsdam
- Germany
| | - S. V. Wegner
- Max Planck Institute for Polymer Research
- Mainz
- Germany
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Alameddine R, Wahl A, Pi F, Bouzalmate K, Limozin L, Charrier A, Sengupta K. Printing Functional Protein Nanodots on Soft Elastomers: From Transfer Mechanism to Cell Mechanosensing. NANO LETTERS 2017; 17:4284-4290. [PMID: 28580787 DOI: 10.1021/acs.nanolett.7b01254] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Living cells sense the physical and chemical nature of their micro/nano environment with exquisite sensitivity. In this context, there is a growing need to functionalize soft materials with micro/nanoscale biochemical patterns for applications in mechanobiology. This, however, is still an engineering challenge. Here a new method is proposed, where submicronic protein-patterns are first formed on glass and are then printed on to an elastomer. The degree of transfer is shown to be governed mainly by hydrophobic interactions and to be influenced by grafting an appropriate fluorophore onto the core protein of interest. The transfer mechanism is probed by measuring the forces of adhesion/cohesion using atomic force microscopy. The transfer of functional arrays of dots with size down to about 400 nm, on elastomers with stiffness ranging from 3 kPa to 7 MPa, is demonstrated. Pilot studies on adhesion of T lymphocytes on such soft patterned substrates are reported.
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Affiliation(s)
| | - Astrid Wahl
- Aix Marseille University, CNRS, CINAM , Marseille, France
| | - Fuwei Pi
- Aix Marseille University, CNRS, CINAM , Marseille, France
| | | | - Laurent Limozin
- Aix Marseille University, CNRS, INSERM, LAI , Marseille, France
| | - Anne Charrier
- Aix Marseille University, CNRS, CINAM , Marseille, France
| | - Kheya Sengupta
- Aix Marseille University, CNRS, CINAM , Marseille, France
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11
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Benard E, Pi F, Ozerov I, Charrier A, Sengupta K. Ligand Nano-cluster Arrays in a Supported Lipid Bilayer. J Vis Exp 2017:55060. [PMID: 28518120 PMCID: PMC5565094 DOI: 10.3791/55060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Currently there is considerable interest in creating ordered arrays of adhesive protein islands in a sea of passivated surface for cell biological studies. In the past years, it has become increasingly clear that living cells respond, not only to the biochemical nature of the molecules presented to them but also to the way these molecules are presented. Creating protein micro-patterns is therefore now standard in many biology laboratories; nano-patterns are also more accessible. However, in the context of cell-cell interactions, there is a need to pattern not only proteins but also lipid bilayers. Such dual proteo-lipidic patterning has so far not been easily accessible. We offer a facile technique to create protein nano-dots supported on glass and propose a method to backfill the inter-dot space with a supported lipid bilayer (SLB). From photo-bleaching of tracer fluorescent lipids included in the SLB, we demonstrate that the bilayer exhibits considerable in-plane fluidity. Functionalizing the protein dots with fluorescent groups allows us to image them and to show that they are ordered in a regular hexagonal lattice. The typical dot size is about 800 nm and the spacing demonstrated here is 2 microns. These substrates are expected to serve as useful platforms for cell adhesion, migration and mechano-sensing studies.
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Affiliation(s)
| | - Fuwei Pi
- Aix-Marseille Université, CNRS, UMR 7325, CINaM; State Key Laboratory of Food Science and Technology, School of Food Science of Jiangnan University
| | - Igor Ozerov
- Aix-Marseille Université, CNRS, UMR 7325, CINaM
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