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Zhou X, Su F, Tian Y, Meldrum DR. Dually fluorescent core-shell microgels for ratiometric imaging in live antigen-presenting cells. PLoS One 2014; 9:e88185. [PMID: 24505422 PMCID: PMC3913776 DOI: 10.1371/journal.pone.0088185] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 01/05/2014] [Indexed: 12/28/2022] Open
Abstract
Core-shell microgels containing sensors/dyes in a matrix were fabricated by two-stage free radical precipitation polymerization method for ratiometric sensing/imaging. The microgels composing of poly(N-isopropylacrylamide) (PNIPAm) shell exhibits a low critical solution temperature (LCST), underwent an entropically driven transition from a swollen state to a deswollen state, which exhibit a hydrodynamic radius of ∼450 nm at 25°C (in vitro) and ∼190 nm at 37°C (in vivo). The microgel’s ability of escaping from lysosome into cytosol makes the microgel be a potential candidate for cytosolic delivery of sensors/probes. Non-invasive imaging/sensing in Antigen-presenting cells (APCs) was feasible by monitoring the changes of fluorescence intensity ratios. Thus, these biocompatible microgels-based imaging/sensing agents may be expected to expand current molecular imaging/sensing techniques into methods applicable to studies in vivo, which could further drive APC-based treatments.
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Affiliation(s)
- Xianfeng Zhou
- Center for Biosignatures Discovery Automation, Biodesign Institute, Arizona State University, Tempe, Arrizona, United States of America
| | - Fengyu Su
- Center for Biosignatures Discovery Automation, Biodesign Institute, Arizona State University, Tempe, Arrizona, United States of America
| | - Yanqing Tian
- Center for Biosignatures Discovery Automation, Biodesign Institute, Arizona State University, Tempe, Arrizona, United States of America
- * E-mail:
| | - Deirdre R. Meldrum
- Center for Biosignatures Discovery Automation, Biodesign Institute, Arizona State University, Tempe, Arrizona, United States of America
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Lck mediates signal transmission from CD59 to the TCR/CD3 pathway in Jurkat T cells. PLoS One 2014; 9:e85934. [PMID: 24454946 PMCID: PMC3893272 DOI: 10.1371/journal.pone.0085934] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 12/03/2013] [Indexed: 01/09/2023] Open
Abstract
The glycosylphosphatidylinositol (GPI)-anchored molecule CD59 has been implicated in the modulation of T cell responses, but the underlying molecular mechanism of CD59 influencing T cell signaling remained unclear. Here we analyzed Jurkat T cells stimulated via anti-CD3ε- or anti-CD59-coated surfaces, using time-resolved single-cell Ca2+ imaging as a read-out for stimulation. This analysis revealed a heterogeneous Ca2+ response of the cell population in a stimulus-dependent manner. Further analysis of T cell receptor (TCR)/CD3 deficient or overexpressing cells showed that CD59-mediated signaling is strongly dependent on TCR/CD3 surface expression. In protein co-patterning and fluorescence recovery after photobleaching experiments no direct physical interaction was observed between CD59 and CD3 at the plasma membrane upon anti-CD59 stimulation. However, siRNA-mediated protein knock-downs of downstream signaling molecules revealed that the Src family kinase Lck and the adaptor molecule linker of activated T cells (LAT) are essential for both signaling pathways. Furthermore, flow cytometry measurements showed that knock-down of Lck accelerates CD3 re-expression at the cell surface after anti-CD59 stimulation similar to what has been observed upon direct TCR/CD3 stimulation. Finally, physically linking Lck to CD3ζ completely abolished CD59-triggered Ca2+ signaling, while signaling was still functional upon direct TCR/CD3 stimulation. Altogether, we demonstrate that Lck mediates signal transmission from CD59 to the TCR/CD3 pathway in Jurkat T cells, and propose that CD59 may act via Lck to modulate T cell responses.
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53
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Randriamampita C, Lellouch AC. Imaging early signaling events in T lymphocytes with fluorescent biosensors. Biotechnol J 2013; 9:203-12. [PMID: 24166755 DOI: 10.1002/biot.201300195] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Revised: 09/09/2013] [Accepted: 10/07/2013] [Indexed: 11/10/2022]
Abstract
Many recent advances in our understanding of T lymphocyte functions in adaptive immunity are derived from sophisticated imaging techniques used to visualize T lymphocyte behavior in vitro and in vivo. A current challenge is to couple such imaging techniques with methods that will allow researchers to visualize signaling phenomenon at the single-cell level. Fluorescent biosensors, either synthetic or genetically encoded, are emerging as important tools for revealing the spatio-temporal regulation of intracellular biochemical events, such as specific enzyme activities or fluctuations in metabolites. In this review, we revisit the development of fluorescent Ca(2+) sensors with which the first experiments visualizing T lymphocyte activation at the single-cell were performed, and which have since become routine tools in immunology. We then examine a number of examples of how fluorescence resonance energy transfer (FRET)-based biosensors have been developed and applied to T lymphocyte migration, adhesion and T-cell receptor (TCR)-mediated signal transduction. These include the study of small GTPases such as RhoA, Rac and Rap1, the tyrosine kinases Lck and ZAP-70, and metabolites such as cAMP and Ca(2+) . Future development and use of biosensors should allow immunologists to reconcile the vast wealth of existing biochemical data concerning T-cell functions with the power of dynamic live-cell imaging.
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Affiliation(s)
- Clotilde Randriamampita
- CNRS UMR8104, Institut Cochin, Paris, France; INSERM U567, Institut Cochin, Paris, France; Paris Descartes University, Institut Cochin, Paris, France.
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Zangle TA, Burnes D, Mathis C, Witte ON, Teitell MA. Quantifying biomass changes of single CD8+ T cells during antigen specific cytotoxicity. PLoS One 2013; 8:e68916. [PMID: 23935904 PMCID: PMC3720853 DOI: 10.1371/journal.pone.0068916] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 06/03/2013] [Indexed: 11/18/2022] Open
Abstract
Existing approaches that quantify cytotoxic T cell responses rely on bulk or surrogate measurements which impede the direct identification of single activated T cells of interest. Single cell microscopy or flow cytometry methodologies typically rely on fluorescent labeling, which limits applicability to primary cells such as human derived T lymphocytes. Here, we introduce a quantitative method to track single T lymphocyte mediated cytotoxic events within a mixed population of cells using live cell interferometry (LCI), a label-free microscopy technique that maintains cell viability. LCI quantifies the mass distribution within individual cells by measuring the phase shift caused by the interaction of light with intracellular biomass. Using LCI, we imaged cytotoxic T cells killing cognate target cells. In addition to a characteristic target cell mass decrease of 20–60% over 1–4 h following attack by a T cell, there was a significant 4-fold increase in T cell mass accumulation rate at the start of the cytotoxic event and a 2–3 fold increase in T cell mass relative to the mass of unresponsive T cells. Direct, label-free measurement of CD8+ T and target cell mass changes provides a kinetic, quantitative assessment of T cell activation and a relatively rapid approach to identify specific, activated patient-derived T cells for applications in cancer immunotherapy.
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Affiliation(s)
- Thomas A. Zangle
- Department of Pathology and Laboratory Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Daina Burnes
- Department of Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, California, United States of America
| | - Colleen Mathis
- Department of Microbiology, Immunology, and Molecular Genetics, University of California Los Angeles, Los Angeles, California, United States of America
| | - Owen N. Witte
- Department of Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Microbiology, Immunology, and Molecular Genetics, University of California Los Angeles, Los Angeles, California, United States of America
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California Los Angeles, Los Angeles, California, United States of America
- Howard Hughes Medical Institute, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail: (ONW); (MAT)
| | - Michael A. Teitell
- Department of Pathology and Laboratory Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California Los Angeles, Los Angeles, California, United States of America
- Bioengineering Interdepartmental Program, University of California Los Angeles, Los Angeles, California, United States of America
- Molecular Biology Institute, Jonsson Comprehensive Cancer Center, and California NanoSystems Institute, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail: (ONW); (MAT)
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55
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Noy E, Pauker MH, Barda-Saad M. Real-time live imaging of T-cell signaling complex formation. J Vis Exp 2013. [PMID: 23851483 DOI: 10.3791/50076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Protection against infectious diseases is mediated by the immune system (1,2). T lymphocytes are the master coordinators of the immune system, regulating the activation and responses of multiple immune cells (3,4). T-cell activation is dependent on the recognition of specific antigens displayed by antigen presenting cells (APCs). The T-cell antigen receptor (TCR) is specific to each T-cell clone and determines antigen specificity (5). The binding of the TCR to the antigen induces the phosphorylation of components of the TCR complex. In order to promote T-cell activation, this signal must be transduced from the membrane to the cytoplasm and the nucleus, initiating various crucial responses such as recruitment of signaling proteins to the TCR;APC site (the immune synapse), their molecular activation, cytoskeletal rearrangement, elevation of intracellular calcium concentration, and changes in gene expression (6,7). The correct initiation and termination of activating signals is crucial for appropriate T-cell responses. The activity of signaling proteins is dependent on the formation and termination of protein-protein interactions, post translational modifications such as protein phosphorylation, formation of protein complexes, protein ubiquitylation and the recruitment of proteins to various cellular sites (8). Understanding the inner workings of the T-cell activation process is crucial for both immunological research and clinical applications. Various assays have been developed in order to investigate protein-protein interactions; however, biochemical assays, such as the widely used co-immunoprecipitation method, do not allow protein location to be discerned, thus precluding the observation of valuable insights into the dynamics of cellular mechanisms. Additionally, these bulk assays usually combine proteins from many different cells that might be at different stages of the investigated cellular process. This can have a detrimental effect on temporal resolution. The use of real-time imaging of live cells allows both the spatial tracking of proteins and the ability to temporally distinguish between signaling events, thus shedding light on the dynamics of the process (9,10). We present a method of real-time imaging of signaling-complex formation during T-cell activation. Primary T-cells or T-cell lines, such as Jurkat, are transfected with plasmids encoding for proteins of interest fused to monomeric fluorescent proteins, preventing non-physiological oligomerization (11). Live T cells are dropped over a coverslip pre-coated with T-cell activating antibody (8,9), which binds to the CD3/TCR complex, inducing T-cell activation while overcoming the need for specific activating antigens. Activated cells are constantly imaged with the use of confocal microscopy. Imaging data are analyzed to yield quantitative results, such as the colocalization coefficient of the signaling proteins.
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Affiliation(s)
- Elad Noy
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University
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56
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Spatial Aspects of HIV Infection. LECTURE NOTES ON MATHEMATICAL MODELLING IN THE LIFE SCIENCES 2013. [DOI: 10.1007/978-1-4614-4178-6_1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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57
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Sherman E, Barr V, Samelson LE. Super-resolution characterization of TCR-dependent signaling clusters. Immunol Rev 2013; 251:21-35. [PMID: 23278738 PMCID: PMC3539238 DOI: 10.1111/imr.12010] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Multi-molecular signaling complexes drive the earliest events of immune cell activation via immunoreceptors with unexplained specificity and speed. Fluorescence microscopy has shown that these complexes form microclusters at the plasma membrane of activated T cells upon engagement of their antigen receptors (TCRs). Although crucial for cell function, much remains to be learned about the molecular content, fine structure, formation mechanisms, and function of these microclusters. Recent advancements in super-resolution microscopy have enabled the study of signaling microclusters at the single molecule level with resolution down to approximately 20 nm. These techniques have now helped to characterize the size distributions of signaling clusters at the plasma membrane of intact cells and to shed light on the formation mechanisms that govern their assembly. Surprisingly, dynamic and functional nanostructures have been identified within the signaling clusters. We expect that these novel methodologies, combined with older techniques, will shed new light on the nature of signaling clusters and their critical role in T-cell activation.
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Affiliation(s)
- Eilon Sherman
- Laboratory of Cellular and Molecular Biology, CCR, NCI, NIH, Bethesda, MD 20892-4256, USA.
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58
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Dorward DA, Lucas CD, Rossi AG, Haslett C, Dhaliwal K. Imaging inflammation: molecular strategies to visualize key components of the inflammatory cascade, from initiation to resolution. Pharmacol Ther 2012; 135:182-99. [PMID: 22627270 DOI: 10.1016/j.pharmthera.2012.05.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Accepted: 05/07/2012] [Indexed: 12/19/2022]
Abstract
Dysregulation of inflammation is central to the pathogenesis of innumerable human diseases. Understanding and tracking the critical events in inflammation are crucial for disease monitoring and pharmacological drug discovery and development. Recent progress in molecular imaging has provided novel insights into spatial associations, molecular events and temporal sequelae in the inflammatory process. While remaining a burgeoning field in pre-clinical research, increasing application in man affords researchers the opportunity to study disease pathogenesis in humans in situ thereby revolutionizing conventional understanding of pathophysiology and potential therapeutic targets. This review provides a description of commonly used molecular imaging modalities, including optical, radionuclide and magnetic resonance imaging, and details key advances and translational opportunities in imaging inflammation from initiation to resolution.
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Affiliation(s)
- D A Dorward
- MRC Centre for Inflammation Research, The Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK.
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59
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Abraham L, Bankhead P, Pan X, Engel U, Fackler OT. HIV-1 Nef limits communication between linker of activated T cells and SLP-76 to reduce formation of SLP-76-signaling microclusters following TCR stimulation. THE JOURNAL OF IMMUNOLOGY 2012; 189:1898-910. [PMID: 22802418 DOI: 10.4049/jimmunol.1200652] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Signal initiation by engagement of the TCR triggers actin rearrangements, receptor clustering, and dynamic organization of signaling complexes to elicit and sustain downstream signaling. Nef, a pathogenicity factor of HIV, disrupts early TCR signaling in target T cells. To define the mechanism underlying this Nef-mediated signal disruption, we employed quantitative single-cell microscopy following surface-mediated TCR stimulation that allows for dynamic visualization of distinct signaling complexes as microclusters (MCs). Despite marked inhibition of actin remodeling and cell spreading, the induction of MCs containing TCR-CD3 or ZAP70 was not affected significantly by Nef. However, Nef potently inhibited the subsequent formation of MCs positive for the signaling adaptor Src homology-2 domain-containing leukocyte protein of 76 kDa (SLP-76) to reduce MC density in Nef-expressing and HIV-1-infected T cells. Further analyses suggested that Nef prevents formation of SLP-76 MCs at the level of the upstream adaptor protein, linker of activated T cells (LAT), that couples ZAP70 to SLP-76. Nef did not disrupt pre-existing MCs positive for LAT. However, the presence of the viral protein prevented de novo recruitment of active LAT into MCs due to retargeting of LAT to an intracellular compartment. These modulations in MC formation and composition depended on Nef's ability to simultaneously disrupt both actin remodeling and subcellular localization of TCR-proximal machinery. Nef thus employs a dual mechanism to disturb early TCR signaling by limiting the communication between LAT and SLP-76 and preventing the dynamic formation of SLP-76-signaling MCs.
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Affiliation(s)
- Libin Abraham
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany
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60
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Campbell KA, Lipinski MJ, Doran AC, Skaflen MD, Fuster V, McNamara CA. Lymphocytes and the adventitial immune response in atherosclerosis. Circ Res 2012; 110:889-900. [PMID: 22427326 DOI: 10.1161/circresaha.111.263186] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Although much of the research on atherosclerosis has focused on the intimal accumulation of lipids and inflammatory cells, there is an increasing amount of interest in the role of the adventitia in coordinating the immune response in atherosclerosis. In this review of the contributions of the adventitia and adventitial lymphocytes to the development of atherosclerosis, we discuss recent research on the formation and structural nature of adventitial immune aggregates, potential mechanisms of crosstalk between the intima, media, and adventitia, specific contributions of B lymphocytes and T lymphocytes, and the role of the vasa vasorum and surrounding perivascular adipose tissue. Furthermore, we highlight techniques for the imaging of lymphocytes in the vasculature.
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Affiliation(s)
- Kirsti A Campbell
- Cardiovascular Research Center, University of Virginia, Charlottesville, USA
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61
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Crites TJ, Chen L, Varma R. A TIRF microscopy technique for real-time, simultaneous imaging of the TCR and its associated signaling proteins. J Vis Exp 2012:3892. [PMID: 22472646 PMCID: PMC3460565 DOI: 10.3791/3892] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Signaling is initiated through the T Cell Receptor (TCR) when it is engaged by antigenic peptide fragments bound by Major Histocompatibility Complex (pMHC) proteins expressed on the surface of antigen presenting cells (APCs). The TCR complex is composed of the ligand binding TCRαβ heterodimer that associates non-covalently with CD3 dimers (the εδ and εγ heterodimers and the ζζ homodimer)1. Upon engagement of the receptor, the CD3 ζ chains are phosphorylated by the Src family kinase, Lck. This leads to the recruitment of the Syk family kinase, Zap70, which is then phosphorylated and activated by Lck. After that, Zap70 phosphorylates the adapter proteins LAT and SLP76, initiating the formation of the proximal signaling complex containing a large number of different signaling molecules2. The formation of this complex eventually results in calcium and Ras-dependent transcription factor activation and the consequent initiation of a complex series of gene expression programs that give rise to T cell differentiation2. TCR signals (and the resulting state of differentiation) are modulated by many other factors, including antigen potency and crosstalk with co-stimulatory/co-inhibitory, chemokine, and cytokine receptors 3-4. Studying the spatial and temporal organization of the proximal signaling complex under various stimulation conditions is, therefore, key to understanding the TCR signaling pathway as well as its regulation by other signaling pathways. One very useful model system to study signaling initiated by the TCR at the plasma membrane in T cells is glass-supported lipid bilayers, as described previously5-6. They can be utilized to present antigenic pMHC complexes, adhesion, and co-stimulatory molecules to T cells-serving as artificial APCs. By imaging the T cells interacting with the lipid bilayer using total internal reflection fluorescence microscopy (TIRFM), we can restrict the excitation to within 100 nm of the space between the glass and the cell surface 7-8. This allows us to image primarily the signaling events occurring at the plasma membrane. As we are interested in imaging the recruitment of signaling proteins to the TCR complex, we describe a two-camera TIRF imaging system wherein the TCR, labeled with fluorescent Fab (fragment antigen binding) fragments of the H57 antibody (purified from hybridoma H57-597, ATCC, ATCC Number:HB-218) which is specific for TCRβ, and signaling proteins, tagged with GFP, may be imaged simultaneously and in real time. This strategy is necessary due to the highly dynamic nature of both the T cells and of the signaling events that are occurring at the TCR. This imaging modality has allowed researchers to image single ligands 9-11 as well as recruitment of signaling molecules to activated receptors and is an excellent system to study biochemistry in-situ12-16.
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Affiliation(s)
- Travis J Crites
- Laboratory of Cellular and Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health
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62
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Sage PT, Varghese LM, Martinelli R, Sciuto TE, Kamei M, Dvorak AM, Springer TA, Sharpe AH, Carman CV. Antigen recognition is facilitated by invadosome-like protrusions formed by memory/effector T cells. THE JOURNAL OF IMMUNOLOGY 2012; 188:3686-99. [PMID: 22442443 DOI: 10.4049/jimmunol.1102594] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Adaptive immunity requires that T cells efficiently scan diverse cell surfaces to identify cognate Ag. However, the basic cellular mechanisms remain unclear. In this study, we investigated this process using vascular endothelial cells, APCs that possess a unique and extremely advantageous, planar morphology. High-resolution imaging revealed that CD4 memory/effector T cells dynamically probe the endothelium by extending submicron-scale, actin-rich "invadosome/podosome-like protrusions" (ILPs). The intimate intercellular contacts enforced by ILPs consistently preceded and supported T cell activation in response to endothelial MHC class II/Ag. The resulting calcium flux stabilized dense arrays of ILPs (each enriched in TCR, protein kinase C-θ, ZAP70, phosphotyrosine, and HS1), forming what we term a podo-synapse. Similar findings were made using CD8 CTLs on endothelium. Furthermore, careful re-examination of both traditional APC models and professional APCs suggests broad relevance for ILPs in facilitating Ag recognition. Together, our results indicate that ILPs function as sensory organelles that serve as actuators of immune surveillance.
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Affiliation(s)
- Peter T Sage
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
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63
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Sagar D, Foss C, El Baz R, Pomper MG, Khan ZK, Jain P. Mechanisms of dendritic cell trafficking across the blood-brain barrier. J Neuroimmune Pharmacol 2012; 7:74-94. [PMID: 21822588 PMCID: PMC3276728 DOI: 10.1007/s11481-011-9302-7] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Accepted: 07/25/2011] [Indexed: 12/14/2022]
Abstract
Although the central nervous system (CNS) is considered to be an immunoprivileged site, it is susceptible to a host of autoimmune as well as neuroinflammatory disorders owing to recruitment of immune cells across the blood-brain barrier into perivascular and parenchymal spaces. Dendritic cells (DCs), which are involved in both primary and secondary immune responses, are the most potent immune cells in terms of antigen uptake and processing as well as presentation to T cells. In light of the emerging importance of DC traficking into the CNS, these cells represent good candidates for targeted immunotherapy against various neuroinflammatory diseases. This review focuses on potential physiological events and receptor interactions between DCs and the microvascular endothelial cells of the brain as they transmigrate into the CNS during degeneration and injury. A clear understanding of the underlying mechanisms involved in DC migration may advance the development of new therapies that manipulate these mechanistic properties via pharmacologic intervention. Furthermore, therapeutic validation should be in concurrence with the molecular imaging techniques that can detect migration of these cells in vivo. Since the use of noninvasive methods to image migration of DCs into CNS has barely been explored, we highlighted potential molecular imaging techniques to achieve this goal. Overall, information provided will bring this important leukocyte population to the forefront as key players in the immune cascade in the light of the emerging contribution of DCs to CNS health and disease.
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Affiliation(s)
- Divya Sagar
- Drexel Institute for Biotechnology and Virology Research, and Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Catherine Foss
- Department of Radiology and Radiological Sciences, Johns Hopkins Medical Institutions, Baltimore, MD 21231, USA
| | - Rasha El Baz
- Drexel Institute for Biotechnology and Virology Research, and Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Martin G. Pomper
- Department of Radiology and Radiological Sciences, Johns Hopkins Medical Institutions, Baltimore, MD 21231, USA
| | - Zafar K. Khan
- Drexel Institute for Biotechnology and Virology Research, and Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Pooja Jain
- Drexel Institute for Biotechnology and Virology Research, and Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA 19129, USA
- Department of Microbiology & Immunology, Drexel Institute for Biotechnology & Virology Research, Drexel University College of Medicine, 3805 Old Easton Road, Doylestown, PA 18902, USA
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64
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Hsu CJ, Hsieh WT, Waldman A, Clarke F, Huseby ES, Burkhardt JK, Baumgart T. Ligand mobility modulates immunological synapse formation and T cell activation. PLoS One 2012; 7:e32398. [PMID: 22384241 PMCID: PMC3284572 DOI: 10.1371/journal.pone.0032398] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 01/30/2012] [Indexed: 12/11/2022] Open
Abstract
T cell receptor (TCR) engagement induces clustering and recruitment to the plasma membrane of many signaling molecules, including the protein tyrosine kinase zeta-chain associated protein of 70 kDa (ZAP70) and the adaptor SH2 domain-containing leukocyte protein of 76 kDa (SLP76). This molecular rearrangement results in formation of the immunological synapse (IS), a dynamic protein array that modulates T cell activation. The current study investigates the effects of apparent long-range ligand mobility on T cell signaling activity and IS formation. We formed stimulatory lipid bilayers on glass surfaces from binary lipid mixtures with varied composition, and characterized these surfaces with respect to diffusion coefficient and fluid connectivity. Stimulatory ligands coupled to these surfaces with similar density and orientation showed differences in their ability to activate T cells. On less mobile membranes, central supramolecular activation cluster (cSMAC) formation was delayed and the overall accumulation of CD3ζ at the IS was reduced. Analysis of signaling microcluster (MC) dynamics showed that ZAP70 MCs exhibited faster track velocity and longer trajectories as a function of increased ligand mobility, whereas movement of SLP76 MCs was relatively insensitive to this parameter. Actin retrograde flow was observed on all surfaces, but cell spreading and subsequent cytoskeletal contraction were more pronounced on mobile membranes. Finally, increased tyrosine phosphorylation and persistent elevation of intracellular Ca2+ were observed in cells stimulated on fluid membranes. These results point to ligand mobility as an important parameter in modulating T cell responses.
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Affiliation(s)
- Chih-Jung Hsu
- Department of Chemistry, The Children's Hospital of Philadelphia and Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Wan-Ting Hsieh
- Department of Chemistry, The Children's Hospital of Philadelphia and Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Abraham Waldman
- Department of Chemistry, The Children's Hospital of Philadelphia and Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Fiona Clarke
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia and Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Eric S. Huseby
- Department of Pathology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Janis K. Burkhardt
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia and Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail: (TB); (JKB)
| | - Tobias Baumgart
- Department of Chemistry, The Children's Hospital of Philadelphia and Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail: (TB); (JKB)
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65
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Suzuki Y, Kabayama K. Convenient and rapid removal of detergent from glycolipids in detergent-resistant membrane microdomains. J Lipid Res 2012; 53:599-608. [PMID: 22217704 DOI: 10.1194/jlr.d020545] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Although detergents are often essential in protocols, they are usually incompatible with further biochemical analysis. There are several methods for detergent removal, but the procedures are complicated or suffer from sample loss. Here, we describe a convenient and rapid method for detergent removal from sialic acid-containing glycosphingolipids (gangliosides) and neutral glycolipids in detergent-resistant membrane (DRM) microdomain. It is based on selective detergent extraction, in which the sample is dried on a glass tube, followed by washing with organic solvent. We investigated 18 organic solvents and used high performance thin-layer chromatography (HPTLC) and matrix-assisted laser desorption/ionization quadrupole ion trap time-of-flight mass spectrometry (MALDI-QIT-TOF MS) to confirm that dichloroethane (DCE) was the most suitable solvent and completely removed the nonionic detergent Triton X-100. Furthermore, DCE extraction effectively removed interference caused by other nonionic, zwitterionic, or ionic detergents in MALDI-QIT-TOF MS analysis.
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Affiliation(s)
- Yusuke Suzuki
- Institute of Glycoscience, Tokai University, Kanagawa, Japan
| | - Kazuya Kabayama
- Institute of Glycoscience, Tokai University, Kanagawa, Japan.
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Davey A, Liu W, Sohn HW, Brzostowski J, Pierce SK. Understanding the initiation of B cell signaling through live cell imaging. Methods Enzymol 2012; 506:265-290. [PMID: 22341229 PMCID: PMC3761359 DOI: 10.1016/b978-0-12-391856-7.00038-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Antibody responses are initiated by the binding of antigens to clonally distributed cell surface B cell receptors (BCRs) that trigger signaling cascades resulting in B cell activation. Using conventional biochemical approaches, the components of the downstream BCR signaling pathways have been described in considerable detail. However, far less is known about the early molecular events by which the binding of antigens to the BCRs initiates BCR signaling. With the recent advent of high resolution, high speed, live cell, and single molecule imaging technologies, these events are just beginning to be elucidated. Understanding the molecular mechanisms underlying the initiation of BCR signaling may provide new targets for therapeutics to block dysregulated BCR signaling in systemic autoimmune diseases and in B cell tumors and to aid in the design of protein subunit vaccines. In this chapter, we describe the general procedures for using these new imaging techniques to investigate the early events in the initiation of BCR signaling.
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Affiliation(s)
- Angel Davey
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, NIH, Rockville, Maryland 20852
| | - Wanli Liu
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, NIH, Rockville, Maryland 20852
| | - Hae Won Sohn
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, NIH, Rockville, Maryland 20852
| | - Joseph Brzostowski
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, NIH, Rockville, Maryland 20852
| | - Susan K. Pierce
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, NIH, Rockville, Maryland 20852
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Zhong L, Zhang Z, Lu X, Huang D, Chen CY, Wang R, Chen ZW. NSOM/QD-based fluorescence-topographic image fusion directly reveals nano-spatial peak-valley polarities of CD69 and CD71 activation molecules on cell-membrane fluctuations during T-cell activation. Immunol Lett 2011; 140:44-51. [PMID: 21704079 DOI: 10.1016/j.imlet.2011.06.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2010] [Revised: 05/20/2011] [Accepted: 06/07/2011] [Indexed: 11/28/2022]
Abstract
Nano-spatial distribution of cell surface molecules on cell membrane fluctuations during T-cell activation has not been reported. In this study, we innovated application of near-field scanning optical microscopy (NSOM)/quantum dots (QDs)-based nanotechnology through three-dimensional image fusion algorithm to merge the simultaneously obtained dual-color fluorescence information and three-dimensional topography. This novel imaging system made it possible to visualize nano-spatial distribution and organization of early-activation molecules CD69 and late-activation molecules CD71 on cell-membrane fluctuations during T-cell activation. Interestingly, most CD69 molecules were clustered to form 250-500nm nano-domains polarizing predominantly in the peak of the cell-membrane fluctuations. In contrast, although CD71 molecules were also clustered as 250-500nm nano-domains, they polarized dominantly in the valley of the cell-membrane fluctuations. The peak-valley polarities of CD69 nano-domains and CD71 nano-domains implied their different functions. CD69 nano-domains polarizing on membrane-peak fluctuations might serve as transient platforms driving TCR/CD3-induced signaling and activation, whereas CD71 nano-domains distributing in the membrane-valley fluctuations appeared to facilitate iron uptake for increased metabolisms in T-cell activation. Importantly, this NSOM/QD-based fluorescence-topographic image fusion provides a powerful tool to visualize nano-spatial distribution of cell-surface molecules on cell-membrane fluctuations and enable better understanding of distribution-function relationship.
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Affiliation(s)
- Liyun Zhong
- Department of Microbiology & Immunology, Center for Primate Biomedical Research, University of Illinois College of Medicine at Chicago, Chicago, IL 60612, United States.
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Tolar P. Inside the microcluster: antigen receptor signalling viewed with molecular imaging tools. Immunology 2011; 133:271-7. [PMID: 21574995 DOI: 10.1111/j.1365-2567.2011.03452.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Over the last decade, live cell imaging has revealed the surprisingly complex orchestration of antigen receptor signalling at the immunological synapse. The imaging studies showed that one of the earliest steps in antigen receptor activation is the formation of submicroscopic clusters, which regulate the early signalling events. However, the molecular mechanisms operating inside these microclusters have remained beyond the resolution of optical microscopy. Recent development of imaging techniques that approach molecular resolution in intact cells offers a first view of the molecular processes inside these structures. Here I review the contributions of molecular imaging of the immunological synapse to our understanding of antigen receptor clustering, binding to antigens, and recruitment of signalling molecules. Finally, I provide an outlook on the future prospects of this rapidly advancing technology.
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Affiliation(s)
- Pavel Tolar
- Division of Immune Cell Biology, MRC National Institute for Medical Research, London, UK.
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