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Cai C, Sun H, Hu L, Fan Z. Visualization of integrin molecules by fluorescence imaging and techniques. ACTA ACUST UNITED AC 2021; 45:229-257. [PMID: 34219865 PMCID: PMC8249084 DOI: 10.32604/biocell.2021.014338] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Integrin molecules are transmembrane αβ heterodimers involved in cell adhesion, trafficking, and signaling. Upon activation, integrins undergo dynamic conformational changes that regulate their affinity to ligands. The physiological functions and activation mechanisms of integrins have been heavily discussed in previous studies and reviews, but the fluorescence imaging techniques -which are powerful tools for biological studies- have not. Here we review the fluorescence labeling methods, imaging techniques, as well as Förster resonance energy transfer assays used to study integrin expression, localization, activation, and functions.
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Affiliation(s)
- Chen Cai
- Department of Immunology, School of Medicine, UConn Health, Farmington, 06030, USA
| | - Hao Sun
- Department of Medicine, University of California, San Diego, La Jolla, 92093, USA
| | - Liang Hu
- Cardiovascular Institute of Zhengzhou University, Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450051, China
| | - Zhichao Fan
- Department of Immunology, School of Medicine, UConn Health, Farmington, 06030, USA
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Jansen MAA, van Herwijnen MJC, van Kooten PJS, Hoek A, van der Zee R, van Eden W, Broere F. Generation of the First TCR Transgenic Mouse with CD4(+) T Cells Recognizing an Anti-inflammatory Regulatory T Cell-Inducing Hsp70 Peptide. Front Immunol 2016; 7:90. [PMID: 27014269 PMCID: PMC4783572 DOI: 10.3389/fimmu.2016.00090] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 02/22/2016] [Indexed: 01/26/2023] Open
Abstract
Antigen-specific regulatory T cells (Tregs) directed at self-antigens are difficult to study since suitable specific tools to isolate and characterize these cells are lacking. A T cell receptor (TCR)-transgenic mouse would generate possibilities to study such antigen-specific T cells. As was shown previously, immunization with the mycobacterial heat shock protein (Hsp) 70-derived peptide B29 and its mouse homologs mB29a and mB29b induced anti-inflammatory responses. Furthermore, B29 induced antigen-specific Tregs in vivo. To study mB29b-specific Tregs, we isolated the TCR from T cell hybridomas generated against mB29b and produced a TCR transgenic mouse that expresses a MHC-class II restricted mB29b-specific TCR. These TCR transgenic CD4+ T cells were found to cross-react with the B29 epitope as identified with peptide-induced proliferation and IL-2 production. Thus, we have successfully generated a novel mouse model with antigen-specific CD4+ T cells that recognize self and bacterial Hsp 70-derived peptides. With this novel mouse model, it will be possible to study primary antigen-specific T cells with specificity for a regulatory Hsp70 T cell epitope. This will enable the isolation and characterization CD4+CD25+ Tregs with a proven specificity. This will provide useful knowledge of the induction, activation, and mode of action of Hsp70-specific Tregs, for instance, during experimental arthritis.
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Affiliation(s)
- Manon A A Jansen
- Department of Infectious Diseases and Immunology, Utrecht University , Utrecht , Netherlands
| | | | - Peter J S van Kooten
- Department of Infectious Diseases and Immunology, Utrecht University , Utrecht , Netherlands
| | - Aad Hoek
- Department of Infectious Diseases and Immunology, Utrecht University , Utrecht , Netherlands
| | - Ruurd van der Zee
- Department of Infectious Diseases and Immunology, Utrecht University , Utrecht , Netherlands
| | - Willem van Eden
- Department of Infectious Diseases and Immunology, Utrecht University , Utrecht , Netherlands
| | - Femke Broere
- Department of Infectious Diseases and Immunology, Utrecht University , Utrecht , Netherlands
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Kang M, Wu T, Wijeratne EMK, Lau EC, Mason DJ, Mesa C, Tillotson J, Zhang DD, Gunatilaka AAL, La Clair JJ, Chapman E. Functional chromatography reveals three natural products that target the same protein with distinct mechanisms of action. Chembiochem 2014; 15:2125-31. [PMID: 25125376 PMCID: PMC4187115 DOI: 10.1002/cbic.201402258] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2014] [Indexed: 01/12/2023]
Abstract
Access to lead compounds with defined molecular targets continues to be a barrier to the translation of natural product resources. As a solution, we developed a system that uses discrete, recombinant proteins as the vehicles for natural product isolation. Here, we describe the use of this functional chromatographic method to identify natural products that bind to the AAA+ chaperone, p97, a promising cancer target. Application of this method to a panel of fungal and plant extracts identified rheoemodin, 1-hydroxydehydroherbarin, and phomapyrrolidone A as distinct p97 modulators. Excitingly, each of these molecules displayed a unique mechanism of p97 modulation. This discovery provides strong support for the application of functional chromatography to the discovery of protein modulators that would likely escape traditional high-throughput or phenotypic screening platforms.
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Affiliation(s)
- MinJin Kang
- College of Pharmacy, Department of Pharmacology and Toxicology, University of Arizona, Tucson, AZ 85721-0207, United States
| | - Tongde Wu
- College of Pharmacy, Department of Pharmacology and Toxicology, University of Arizona, Tucson, AZ 85721-0207, United States
| | - E. M. Kithsiri Wijeratne
- Southwest Center for Natural Products Research and Commercialization, School of Natural Resources and the Environment, College of Agriculture and Life Sciences, University of Arizona, Tucson, AZ 85706-6800, United States
| | - Eric C. Lau
- College of Pharmacy, Department of Pharmacology and Toxicology, University of Arizona, Tucson, AZ 85721-0207, United States
| | - Damian J. Mason
- College of Pharmacy, Department of Pharmacology and Toxicology, University of Arizona, Tucson, AZ 85721-0207, United States
| | - Celestina Mesa
- College of Pharmacy, Department of Pharmacology and Toxicology, University of Arizona, Tucson, AZ 85721-0207, United States
| | - Joseph Tillotson
- College of Pharmacy, Department of Pharmacology and Toxicology, University of Arizona, Tucson, AZ 85721-0207, United States
| | - Donna D. Zhang
- College of Pharmacy, Department of Pharmacology and Toxicology, University of Arizona, Tucson, AZ 85721-0207, United States
| | - A. A. Leslie Gunatilaka
- Southwest Center for Natural Products Research and Commercialization, School of Natural Resources and the Environment, College of Agriculture and Life Sciences, University of Arizona, Tucson, AZ 85706-6800, United States
| | - James J. La Clair
- Xenobe Research Institute, P. O. Box 3052, San Diego, CA 92163-1052, United States
| | - Eli Chapman
- College of Pharmacy, Department of Pharmacology and Toxicology, University of Arizona, Tucson, AZ 85721-0207, United States
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Miranda SCCC, Silva GAB, Mendes RM, Abreu FAM, Caliari MV, Alves JB, Goes AM. Mesenchymal stem cells associated with porous chitosan-gelatin scaffold: A potential strategy for alveolar bone regeneration. J Biomed Mater Res A 2012; 100:2775-86. [DOI: 10.1002/jbm.a.34214] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2011] [Revised: 02/15/2012] [Accepted: 03/30/2012] [Indexed: 12/26/2022]
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He L, Wu X, Siegel R, Lipsky PE. TRAF6 regulates cell fate decisions by inducing caspase 8-dependent apoptosis and the activation of NF-kappaB. J Biol Chem 2006; 281:11235-49. [PMID: 16436380 DOI: 10.1074/jbc.m508779200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Tumor necrosis factor receptor-associated factor 6 (TRAF6) functions as an adaptor, positively regulating the NF-kappaB pathway. Here we report a new function of human TRAF6, the direct stimulation of apoptosis. The mechanism of apoptosis induction results from the capacity of human TRAF6 to interact and activate caspase 8. Both the C-terminal TRAF domain of human TRAF6, which directly interacts with the death effector domain of pro-caspase 8, and the N-terminal RING domain, which is required for activation of caspase 8, are necessary for the induction of apoptosis. The role of endogenous TRAF6 in regulating apoptosis was confirmed by extinguishing TRAF6 expression with specific small-hairpin RNA that resulted in diminished spontaneous apoptosis and resistance to induced apoptosis. In contrast to the human molecule, murine TRAF6 displayed less ability to induce apoptosis and a greater capacity to stimulate NF-kappaB activity. Human and murine TRAF6 are similar except in the region between zinc finger 5 and the TRAF domains. Reciprocal transfer of this connecting region completely exchanged the ability of human and murine TRAF6 to induce apoptosis and activate NF-kappaB. Unique regions of TRAF6 therefore play an important role in determining cell fate.
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Affiliation(s)
- Liusheng He
- Flow Cytometry Section, Office of Science and Technology, NIAMS, National Institutes of Health, Bethesda, Maryland 20892, USA.
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New trends in tumor biology: transfection of a human hepatoblastoma cell line with green fluorescent protein. J Pediatr Surg 2005; 40:653-7. [PMID: 15852273 DOI: 10.1016/j.jpedsurg.2004.12.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND/PURPOSE Enhanced green fluorescent protein (eGFP) is widely used as a marker in different biologic systems. After vector transfection, eGFP is expressed by eukaryotic cells and can be visualized using fluorescent microscopy. The aim of this study was to establish an eGFP-transfected human hepatoblastoma (HB) cell line as tool for further basic research studies. METHODS The HB cell line HUH6 was transfected with the pEGFP-N1 vector by liposomal transfection. Enhanced green fluorescent protein-positive cells were sorted out by fluorescence-activated cell sort and selected using G418 resistance. Expression of eGFP-messenger RNA was assessed by single-cell reverse transcriptase polymerase chain reaction after laser microdissection. Original and transfected cells were compared biologically and cytomorphologically. RESULTS Vector transfection produced up to 15% eGFP-positive cells. After fluorescence-activated cell sort and G418 selection, a pure cell line was established with 100% eGFP-positive cells. Reverse transcriptase polymerase chain reaction revealed constant expression of eGFP-messenger RNA in fluorescending cells. Analysis of cell characteristics revealed no differences between transfected and original cells. CONCLUSIONS For the first time, the authors established an eGFP-transfected HB cell line. This cell line can serve as a promising tool for further studies investigating HB in vitro and in vivo. Our model might also be a basis for similar work on other pediatric solid tumors.
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Cahalan MD, Parker I, Wei SH, Miller MJ. Two-photon tissue imaging: seeing the immune system in a fresh light. Nat Rev Immunol 2002; 2:872-80. [PMID: 12415310 PMCID: PMC2749751 DOI: 10.1038/nri935] [Citation(s) in RCA: 345] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Many lymphocyte functions, such as antigen recognition, take place deep in densely populated lymphoid organs. Because direct in vivo observation was not possible, the dynamics of immune-cell interactions have been inferred or extrapolated from in vitro studies. Two-photon fluorescence excitation uses extremely brief (<1 picosecond) and intense pulses of light to 'see' directly into living tissues, to a greater depth and with less phototoxicity than conventional imaging methods. Two-photon microscopy, in combination with newly developed indicator molecules, promises to extend single-cell approaches to the in vivo setting and to reveal in detail the cellular collaborations that underlie the immune response.
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Affiliation(s)
- Michael D Cahalan
- Department of Physiology, University of California, Irvine, California 92697-4561, USA.
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Schrum AG, Turka LA. The proliferative capacity of individual naive CD4(+) T cells is amplified by prolonged T cell antigen receptor triggering. J Exp Med 2002; 196:793-803. [PMID: 12235212 PMCID: PMC2194051 DOI: 10.1084/jem.20020158] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Strong antigenic encounter by T cells rapidly induces immunological synapse formation and surface T cell receptor (TCR) downregulation. Although surface TCR expression can remain low for several days, T cells can still sustain antigenic signaling. It has been unclear whether prolonged antigenic signaling occurs in the absence of surface TCR replenishment, being maintained by a few "nondownregulatable" surface TCRs that might reside in a synaptosomal structure. Alternatively, the low surface TCR level induced by antigen might represent a dynamic state of expression involving continual surface TCR replenishment, reengagement by antigen, and ongoing downregulation. To resolve this issue, we studied in vivo-generated, dual-specificity primary naive CD4(+) T cells. On these cells, antigenic stimulus exclusively downregulated antigen-specific, but not antigen-nonspecific, TCRs. In addition to providing a means to track TCR engagement, this also allowed us to use the antigen nonspecific TCR to track TCR expression in isolation from TCR engagement by antigen. Surface TCR replenishment began within the first day of stimulation, and occurred synchronously with continuous antigen-specific TCR engagement and downregulation. Furthermore, by enhancing CD25 expression, extended signaling through surface-replenishing TCRs significantly amplified the number of daughter cells generated by naive CD4(+) T cells that had already committed to proliferate. This effect required TCR engagement and could not be substituted for by interleukin 2. These data demonstrate that TCR triggering and consumption can occur over an extended period of time, with a significant impact on the effector responses evoked from naive CD4(+) T cells.
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Affiliation(s)
- Adam G Schrum
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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