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Wilhelm KB, Vissa A, Groves JT. Differential Roles of Kinetic On- and Off-Rates in T-Cell Receptor Signal Integration Revealed with a Modified Fab'-DNA Ligand. bioRxiv 2024:2024.04.01.587588. [PMID: 38617215 PMCID: PMC11014569 DOI: 10.1101/2024.04.01.587588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Antibody-derived T-cell receptor (TCR) agonists are commonly used to activate T cells. While antibodies can trigger TCRs regardless of clonotype, they bypass native T cell signal integration mechanisms that rely on monovalent, membrane-associated, and relatively weakly-binding ligand in the context of cellular adhesion. Commonly used antibodies and their derivatives bind much more strongly than native peptide-MHC (pMHC) ligands bind their cognate TCRs. Because ligand dwell time is a critical parameter that tightly correlates with physiological function of the TCR signaling system, there is a general need, both in research and therapeutics, for universal TCR ligands with controlled kinetic binding parameters. To this end, we have introduced point mutations into recombinantly expressed α-TCRβ H57 Fab to modulate the dwell time of monovalent Fab binding to TCR. When tethered to a supported lipid bilayer via DNA complementation, these monovalent Fab'-DNA ligands activate T cells with potencies well-correlated with their TCR binding dwell time. Single-molecule tracking studies in live T cells reveal that individual binding events between Fab'-DNA ligands and TCRs elicit local signaling responses closely resembling native pMHC. The unique combination of high on- and off-rate of the H57 R97L mutant enables direct observations of cooperative interplay between ligand binding and TCR-proximal condensation of the linker for activation of T cells (LAT), which is not readily visualized with pMHC. This work provides insights into how T cells integrate kinetic information from synthetic ligands and introduces a method to develop affinity panels for polyclonal T cells, such as cells from a human patient.
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Affiliation(s)
- Kiera B Wilhelm
- Department of Chemistry, University of California-Berkeley, Berkeley, CA, 93720
| | - Anand Vissa
- Department of Chemistry, University of California-Berkeley, Berkeley, CA, 93720
| | - Jay T Groves
- Department of Chemistry, University of California-Berkeley, Berkeley, CA, 93720
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2
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Rogers J, Ma R, Foote A, Hu Y, Salaita K. Force-Induced Site-Specific Enzymatic Cleavage Probes Reveal That Serial Mechanical Engagement Boosts T Cell Activation. J Am Chem Soc 2024; 146:7233-7242. [PMID: 38451498 PMCID: PMC10958510 DOI: 10.1021/jacs.3c08137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 01/11/2024] [Accepted: 01/12/2024] [Indexed: 03/08/2024]
Abstract
The T cell membrane is studded with >104 T cell receptors (TCRs) that are used to scan target cells to identify short peptide fragments associated with viral infection or cancerous mutation. These peptides are presented as peptide-major-histocompatibility complexes (pMHCs) on the surface of virtually all nucleated cells. The TCR-pMHC complex forms at cell-cell junctions, is highly transient, and experiences mechanical forces. An important question in this area pertains to the role of the force duration in immune activation. Herein, we report the development of force probes that autonomously terminate tension within a time window following mechanical triggering. Force-induced site-specific enzymatic cleavage (FUSE) probes tune the tension duration by controlling the rate of a force-triggered endonuclease hydrolysis reaction. This new capability provides a method to study how the accumulated force duration contributes to T cell activation. We screened DNA sequences and identified FUSE probes that disrupt mechanical interactions with F > 7.1 piconewtons (pN) between TCRs and pMHCs. This rate of disruption, or force lifetime (τF), is tunable from tens of minutes down to 1.9 min. T cells challenged with FUSE probes with F > 7.1 pN presenting cognate antigens showed up to a 23% decrease in markers of early activation. FUSE probes with F > 17.0 pN showed weaker influence on T cell triggering further showing that TCR-pMHC with F > 17.0 pN are less frequent compared to F > 7.1 pN. Taken together, FUSE probes allow a new strategy to investigate the role of force dynamics in mechanotransduction broadly and specifically suggest a model of serial mechanical engagement boosting TCR activation.
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Affiliation(s)
- Jhordan Rogers
- Department
of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Rong Ma
- Department
of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Alexander Foote
- Department
of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Yuesong Hu
- Department
of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Khalid Salaita
- Department
of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
- Wallace
H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332, United States
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Jeffreys N, Brockman JM, Zhai Y, Ingber DE, Mooney DJ. Mechanical forces amplify TCR mechanotransduction in T cell activation and function. Appl Phys Rev 2024; 11:011304. [PMID: 38434676 PMCID: PMC10848667 DOI: 10.1063/5.0166848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 12/08/2023] [Indexed: 03/05/2024]
Abstract
Adoptive T cell immunotherapies, including engineered T cell receptor (eTCR) and chimeric antigen receptor (CAR) T cell immunotherapies, have shown efficacy in treating a subset of hematologic malignancies, exhibit promise in solid tumors, and have many other potential applications, such as in fibrosis, autoimmunity, and regenerative medicine. While immunoengineering has focused on designing biomaterials to present biochemical cues to manipulate T cells ex vivo and in vivo, mechanical cues that regulate their biology have been largely underappreciated. This review highlights the contributions of mechanical force to several receptor-ligand interactions critical to T cell function, with central focus on the TCR-peptide-loaded major histocompatibility complex (pMHC). We then emphasize the role of mechanical forces in (i) allosteric strengthening of the TCR-pMHC interaction in amplifying ligand discrimination during T cell antigen recognition prior to activation and (ii) T cell interactions with the extracellular matrix. We then describe approaches to design eTCRs, CARs, and biomaterials to exploit TCR mechanosensitivity in order to potentiate T cell manufacturing and function in adoptive T cell immunotherapy.
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Affiliation(s)
| | | | - Yunhao Zhai
- Wyss Institute for Biologically Inspired Engineering, Boston, Massachusetts 02115, USA
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4
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Hou Y, Treanor B. DNA origami: Interrogating the nano-landscape of immune receptor activation. Biophys J 2023:S0006-3495(23)00649-5. [PMID: 37838832 DOI: 10.1016/j.bpj.2023.10.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 09/22/2023] [Accepted: 10/12/2023] [Indexed: 10/16/2023] Open
Abstract
The immune response is orchestrated by elaborate protein interaction networks that interweave ligand-mediated receptor reorganization with signaling cascades. While the biochemical processes have been extensively investigated, delineating the biophysical principles governing immune receptor activation has remained challenging due to design limitations of traditional ligand display platforms. These constraints have been overcome by advances in DNA origami nanotechnology, enabling unprecedented control over ligand geometry on configurable scaffolds. It is now possible to systematically dissect the independent roles of ligand stoichiometry, spatial distribution, and rigidity in immune receptor activation, signaling, and cooperativity. In this review, we highlight pioneering efforts in manipulating the ligand presentation landscape to understand immune receptor triggering and to engineer functional immune responses.
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Affiliation(s)
- Yuchen Hou
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario.
| | - Bebhinn Treanor
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario; Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario; Department of Immunology, University of Toronto, Toronto, Ontario.
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5
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Rogers J, Ma R, Hu Y, Salaita K. Force-induced site-specific enzymatic cleavage probes reveal that serial mechanical engagement boosts T cell activation. bioRxiv 2023:2023.08.07.552310. [PMID: 37609308 PMCID: PMC10441320 DOI: 10.1101/2023.08.07.552310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
The surface of T cells is studded with T cell receptors (TCRs) that are used to scan target cells to identify peptide-major histocompatibility complexes (pMHCs) signatures of viral infection or cancerous mutation. It is now established that the TCR-pMHC complex is highly transient and experiences mechanical forces that augment the fidelity of T cell activation. An important question in this area pertains to the role of force duration in immune activation. Herein, we report the development of force probes that autonomously terminate tension within a time window following mechanical triggering. Force-induced site-specific enzymatic cleavage (FUSE) probes tune tension duration by controlling the rate of a force-triggered endonuclease hydrolysis reaction. This new capability provides a method to study how accumulated force duration contributes to T cell activation. We screened DNA sequences and identified FUSE probes that disrupt mechanical interactions with F >7.1 piconewtons (pN) between TCRs and pMHCs. Force lifetimes (τF) are tunable from tens of min down to 1.9 min. T cells challenged with FUSE probes presenting cognate antigens with τF of 1.9 min demonstrated dampened markers of early activation, thus demonstrating that repeated mechanical sampling boosts TCR activation. Repeated mechanical sampling F >7.1 pN was found to be particularly critical at lower pMHC antigen densities, wherein the T cell activation declined by 23% with τF of 1.9 min. FUSE probes with F >17.0 pN response showed weaker influence on T cell triggering further showing that TCR-pMHC with F >17.0 pN are less frequent compared to F >7.1 pN. Taken together, FUSE probes allow a new strategy to investigate the role of force dynamics in mechanotransduction broadly and specifically suggest a model of serial mechanical engagement in antigen recognition.
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Affiliation(s)
- Jhordan Rogers
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia, 30322, USA
| | - Rong Ma
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia, 30322, USA
| | - Yuesong Hu
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia, 30322, USA
| | - Khalid Salaita
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia, 30322, USA
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, 30332, USA
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Webster ER, Liu KN, Rawle RJ, Boxer SG. Modulating the Influenza A Virus-Target Membrane Fusion Interface With Synthetic DNA-Lipid Receptors. Langmuir 2022; 38:2354-2362. [PMID: 35143209 PMCID: PMC9038422 DOI: 10.1021/acs.langmuir.1c03247] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Influenza A virus (IAV) binds to sialylated glycans on the cell membrane before endocytosis and fusion. Cell-surface glycans are highly heterogeneous in length and glycosylation density, which leads to variations in the distance and rigidity with which IAV is held away from the cell membrane. To gain mechanistic insight into how receptor length and rigidity impact the mechanism of IAV entry, we employed synthetic DNA-lipids as highly tunable surrogate receptors. We tethered IAV to target membranes with a panel of DNA-lipids to investigate the effects of the distance and tether flexibility between virions and target membranes on the kinetics of IAV binding and fusion. Tether length and the presence of a flexible linker led to higher rates of IAV binding, while the efficiencies of lipid and content mixing were typically lower for longer and more rigid DNA tethers. For all DNA tether modifications, we found that the rates of IAV lipid and content mixing were unchanged. These results suggest that variations in the interface between IAV and a target membrane do not significantly impact the rate-limiting step of fusion or the low-pH-triggered engagement of viral fusion peptides with the target membrane. However, our results imply that the flexibility of the viral receptor is important for ensuring that hemifusion events are able to successfully proceed to pore formation.
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Affiliation(s)
- Elizabeth R Webster
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Katherine N Liu
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Robert J Rawle
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Steven G Boxer
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
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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] [What about the content of this article? (0)] [Affiliation(s)] [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.
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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,
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