1
|
Ding M, Baker D. Recent advances in high-throughput flow cytometry for drug discovery. Expert Opin Drug Discov 2020; 16:303-317. [PMID: 33054417 DOI: 10.1080/17460441.2021.1826433] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION High-throughput flow cytometry (HTFC) has proven to be an important technology in drug discovery. The use of HTFC enables multi-parametric screening of suspension cells containing heterogenous cell populations and coated particles for screening proteins of interest. Novel targets, novel cell markers and compound clusters for drug development have been identified from HTFC screens. AREAS COVERED In this article, the authors focus on reviewing the recent HTFC applications reported during the last 5-6 years, including drug discovery screens and studies for immune, immune-oncology, infectious and inflammatory diseases. The main HTFC approaches, development of HTFC systems, and automated sample preparation systems for HTFC are also discussed. EXPERT OPINION The advance of HTFC technology coupled with automated sample acquisition and sample preparation has demonstrated its utility in screening large numbers of compounds using suspension cells, facilitated screening of disease-relevant human primary cells, and enabled deep understanding of mechanism of action by analyzing multiple parameters. The authors see HTFC as a very valuable tool in immune, immune-oncology, infectious and inflammatory diseases where immune cells play essential roles.
Collapse
Affiliation(s)
- Mei Ding
- Discovery Biology, Discovery Sciences, R&D, AstraZeneca, Gothenburg, Sweden
| | - David Baker
- Discovery Biology, Discovery Sciences, R&D, AstraZeneca, Cambridge, UK
| |
Collapse
|
2
|
Perkins LA, Bruchez MP. Fluorogen activating protein toolset for protein trafficking measurements. Traffic 2020; 21:333-348. [PMID: 32080949 PMCID: PMC7462100 DOI: 10.1111/tra.12722] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 02/17/2020] [Accepted: 02/18/2020] [Indexed: 12/11/2022]
Abstract
Throughout the past decade the use of fluorogen activating proteins (FAPs) has expanded with several unique reporter dyes that support a variety of methods to specifically quantify protein trafficking events. The platform's capabilities have been demonstrated in several systems and shared for widespread use. This review will highlight the current FAP labeling techniques for protein traffic measurements and focus on the use of the different designed fluorogenic dyes for selective and specific labeling applications.
Collapse
Affiliation(s)
- Lydia A. Perkins
- School of MedicineUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Marcel P. Bruchez
- The Department of Biological SciencesCarnegie MellonPittsburghPennsylvaniaUSA
- Department of ChemistryCarnegie MellonPittsburghPennsylvaniaUSA
- Molecular and Biosensor Imaging CenterCarnegie MellonPittsburghPennsylvaniaUSA
| |
Collapse
|
3
|
Ding M, Clark R, Bardelle C, Backmark A, Norris T, Williams W, Wigglesworth M, Howes R. Application of High-Throughput Flow Cytometry in Early Drug Discovery: An AstraZeneca Perspective. SLAS DISCOVERY 2018; 23:719-731. [PMID: 29787326 DOI: 10.1177/2472555218775074] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Flow cytometry is a powerful tool providing multiparametric analysis of single cells or particles. The introduction of faster plate-based sampling technologies on flow cytometers has transformed the technology into one that has become attractive for higher throughput drug discovery screening. This article describes AstraZeneca's perspectives on the deployment and application of high-throughput flow cytometry (HTFC) platforms for small-molecule high-throughput screening (HTS), structure-activity relationship (SAR) and phenotypic screening, and antibody screening. We describe the overarching HTFC workflow, including the associated automation and data analysis, along with a high-level overview of our HTFC assay portfolio. We go on to discuss the practical challenges encountered and solutions adopted in the course of our deployment of HTFC, as well as future enhancements and expansion of the technology to new areas of drug discovery.
Collapse
Affiliation(s)
- Mei Ding
- 1 Discovery Sciences, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - Roger Clark
- 2 Discovery Sciences, IMED Biotech Unit, AstraZeneca, Cambridge, UK
| | | | - Anna Backmark
- 1 Discovery Sciences, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - Tyrrell Norris
- 1 Discovery Sciences, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - Wendy Williams
- 4 Antibody Discovery and Protein Engineering, MedImmune, Cambridge, UK
| | - Mark Wigglesworth
- 3 Discovery Sciences, IMED Biotech Unit, AstraZeneca, Macclesfield, UK
| | - Rob Howes
- 1 Discovery Sciences, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| |
Collapse
|
4
|
Xu S, Hu HY. Fluorogen-activating proteins: beyond classical fluorescent proteins. Acta Pharm Sin B 2018; 8:339-348. [PMID: 29881673 PMCID: PMC5989828 DOI: 10.1016/j.apsb.2018.02.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 02/11/2018] [Accepted: 02/18/2018] [Indexed: 01/09/2023] Open
Abstract
Fluorescence imaging is a powerful technique for the real-time noninvasive monitoring of protein dynamics. Recently, fluorogen activating proteins (FAPs)/fluorogen probes for protein imaging were developed. Unlike the traditional fluorescent proteins (FPs), FAPs do not fluoresce unless bound to their specific small-molecule fluorogens. When using FAPs/fluorogen probes, a washing step is not required for the removal of free probes from the cells, thus allowing rapid and specific detection of proteins in living cells with high signal-to-noise ratio. Furthermore, with different fluorogens, living cell multi-color proteins labeling system was developed. In this review, we describe about the discovery of FAPs, the design strategy of FAP fluorogens, the application of the FAP technology and the advances of FAP technology in protein labeling systems.
Collapse
Affiliation(s)
- Shengnan Xu
- State Key Laboratory of Bioactive Substances and Function of Natural Medicine, Institute of Materia Medica, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing 100050, China
| | - Hai-Yu Hu
- State Key Laboratory of Bioactive Substances and Function of Natural Medicine, Institute of Materia Medica, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing 100050, China
- Beijing Key Laboratory of Active Substances Discovery and Drugability Evaluation, Institute of Materia Medica, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing 100050, China
| |
Collapse
|
5
|
A cell surface display fluorescent biosensor for measuring MMP14 activity in real-time. Sci Rep 2018; 8:5916. [PMID: 29651043 PMCID: PMC5897415 DOI: 10.1038/s41598-018-24080-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 03/23/2018] [Indexed: 01/16/2023] Open
Abstract
Despite numerous recent advances in imaging technologies, one continuing challenge for cell biologists and microscopists is the visualization and measurement of endogenous proteins as they function within living cells. Achieving this goal will provide a tool that investigators can use to associate cellular outcomes with the behavior and activity of many well-studied target proteins. Here, we describe the development of a plasmid-based fluorescent biosensor engineered to measure the location and activity of matrix metalloprotease-14 (MMP14). The biosensor design uses fluorogen-activating protein technology coupled with a MMP14-selective protease sequence to generate a binary, “switch-on” fluorescence reporter capable of measuring MMP14 location, activity, and temporal dynamics. The MMP14-fluorogen activating protein biosensor approach is applicable to both short and long-term imaging modalities and contains an adaptable module that can be used to study many membrane-bound proteases. This MMP14 biosensor promises to serve as a tool for the advancement of a broad range of investigations targeting MMP14 activity during cell migration in health and disease.
Collapse
|
6
|
Li C, Tebo AG, Gautier A. Fluorogenic Labeling Strategies for Biological Imaging. Int J Mol Sci 2017; 18:ijms18071473. [PMID: 28698494 PMCID: PMC5535964 DOI: 10.3390/ijms18071473] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 07/03/2017] [Accepted: 07/06/2017] [Indexed: 12/27/2022] Open
Abstract
The spatiotemporal fluorescence imaging of biological processes requires effective tools to label intracellular biomolecules in living systems. This review presents a brief overview of recent labeling strategies that permits one to make protein and RNA strongly fluorescent using synthetic fluorogenic probes. Genetically encoded tags selectively binding the exogenously applied molecules ensure high labeling selectivity, while high imaging contrast is achieved using fluorogenic chromophores that are fluorescent only when bound to their cognate tag, and are otherwise dark. Beyond avoiding the need for removal of unbound synthetic dyes, these approaches allow the development of sophisticated imaging assays, and open exciting prospects for advanced imaging, particularly for multiplexed imaging and super-resolution microscopy.
Collapse
Affiliation(s)
- Chenge Li
- École Normale Supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Département de Chimie, PASTEUR, 24 rue Lhomond, 75005 Paris, France.
- Sorbonne Universités, UPMC Univ Paris 06, ENS, CNRS, PASTEUR, 75005 Paris, France.
| | - Alison G Tebo
- École Normale Supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Département de Chimie, PASTEUR, 24 rue Lhomond, 75005 Paris, France.
- Sorbonne Universités, UPMC Univ Paris 06, ENS, CNRS, PASTEUR, 75005 Paris, France.
| | - Arnaud Gautier
- École Normale Supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Département de Chimie, PASTEUR, 24 rue Lhomond, 75005 Paris, France.
- Sorbonne Universités, UPMC Univ Paris 06, ENS, CNRS, PASTEUR, 75005 Paris, France.
| |
Collapse
|
7
|
Effect of human cytomegalovirus (HCMV) US27 on CXCR4 receptor internalization measured by fluorogen-activating protein (FAP) biosensors. PLoS One 2017; 12:e0172042. [PMID: 28207860 PMCID: PMC5313195 DOI: 10.1371/journal.pone.0172042] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 01/30/2017] [Indexed: 01/08/2023] Open
Abstract
Human cytomegalovirus (HCMV) is a widespread pathogen and a member of the Herpesviridae family. HCMV has a large genome that encodes many genes that are non-essential for virus replication but instead play roles in manipulation of the host immune environment. One of these is the US27 gene, which encodes a protein with homology to the chemokine receptor family of G protein-coupled receptors (GPCRs). The US27 protein has no known chemokine ligands but can modulate the signaling activity of host receptor CXCR4. We investigated the mechanism for enhanced CXCR4 signaling in the presence of US27 using a novel biosensor system comprised of fluorogen activating proteins (FAPs). FAP-tagged CXCR4 and US27 were used to explore receptor internalization and recovery dynamics, and the results demonstrate that significantly more CXCR4 internalization was observed in the presence of US27 compared to CXCR4 alone upon stimulation with CXCL12. While ligand-induced endocytosis rates were higher, steady state internalization of CXCR4 was not affected by US27. Additionally, US27 underwent rapid endocytosis at a rate that was independent of either CXCR4 expression or CXCL12 stimulation. These results demonstrate that one mechanism by which US27 can enhance CXCR4 signaling is to alter receptor internalization dynamics, which could ultimately have the effect of promoting virus dissemination by increasing trafficking of HCMV-infected cells to tissues where CXCL12 is highly expressed.
Collapse
|
8
|
Wu Y, Stauffer SR, Stanfield RL, Tapia PH, Ursu O, Fisher GW, Szent-Gyorgyi C, Evangelisti A, Waller A, Strouse JJ, Carter MB, Bologa C, Gouveia K, Poslusney M, Waggoner AS, Lindsley CW, Jarvik JW, Sklar LA. Discovery of Small-Molecule Nonfluorescent Inhibitors of Fluorogen-Fluorogen Activating Protein Binding Pair. ACTA ACUST UNITED AC 2015; 21:74-87. [PMID: 26442911 DOI: 10.1177/1087057115609145] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 09/09/2015] [Indexed: 11/17/2022]
Abstract
A new class of biosensors, fluorogen activating proteins (FAPs), has been successfully used to track receptor trafficking in live cells. Unlike the traditional fluorescent proteins (FPs), FAPs do not fluoresce unless bound to their specific small-molecule fluorogens, and thus FAP-based assays are highly sensitive. Application of the FAP-based assay for protein trafficking in high-throughput flow cytometry resulted in the discovery of a new class of compounds that interferes with the binding between fluorogens and FAP, thus blocking the fluorescence signal. These compounds are high-affinity, nonfluorescent analogs of fluorogens with little or no toxicity to the tested cells and no apparent interference with the normal function of FAP-tagged receptors. The most potent compound among these, N,4-dimethyl-N-(2-oxo-2-(4-(pyridin-2-yl)piperazin-1-yl)ethyl)benzenesulfonamide (ML342), has been investigated in detail. X-ray crystallographic analysis revealed that ML342 competes with the fluorogen, sulfonated thiazole orange coupled to diethylene glycol diamine (TO1-2p), for the same binding site on a FAP, AM2.2. Kinetic analysis shows that the FAP-fluorogen interaction is more complex than a homogeneous one-site binding process, with multiple conformational states of the fluorogen and/or the FAP, and possible dimerization of the FAP moiety involved in the process.
Collapse
Affiliation(s)
- Yang Wu
- Department of Pathology, University of New Mexico, Albuquerque, NM, USA Center for Molecular Discovery, University of New Mexico, Albuquerque, NM, USA
| | - Shaun R Stauffer
- Vanderbilt Specialized Chemistry Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Robyn L Stanfield
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Phillip H Tapia
- Center for Molecular Discovery, University of New Mexico, Albuquerque, NM, USA
| | - Oleg Ursu
- Center for Molecular Discovery, University of New Mexico, Albuquerque, NM, USA
| | - Gregory W Fisher
- Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, PA, USA
| | | | - Annette Evangelisti
- Center for Molecular Discovery, University of New Mexico, Albuquerque, NM, USA
| | - Anna Waller
- Center for Molecular Discovery, University of New Mexico, Albuquerque, NM, USA
| | - J Jacob Strouse
- Center for Molecular Discovery, University of New Mexico, Albuquerque, NM, USA
| | - Mark B Carter
- Center for Molecular Discovery, University of New Mexico, Albuquerque, NM, USA
| | - Cristian Bologa
- Center for Molecular Discovery, University of New Mexico, Albuquerque, NM, USA
| | - Kristine Gouveia
- Center for Molecular Discovery, University of New Mexico, Albuquerque, NM, USA
| | - Mike Poslusney
- Vanderbilt Specialized Chemistry Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Alan S Waggoner
- Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, PA, USA Department of Biological Science, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Craig W Lindsley
- Vanderbilt Specialized Chemistry Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Jonathan W Jarvik
- Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, PA, USA Department of Biological Science, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Larry A Sklar
- Department of Pathology, University of New Mexico, Albuquerque, NM, USA Center for Molecular Discovery, University of New Mexico, Albuquerque, NM, USA
| |
Collapse
|
9
|
Bruchez MP. Dark dyes-bright complexes: fluorogenic protein labeling. Curr Opin Chem Biol 2015; 27:18-23. [PMID: 26056741 DOI: 10.1016/j.cbpa.2015.05.014] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 05/15/2015] [Accepted: 05/19/2015] [Indexed: 11/16/2022]
Abstract
Complexes formed between organic dyes and genetically encoded proteins combine the advantages of stable and tunable fluorescent molecules and targetable, biologically integrated labels. To overcome the challenges imposed by labeling with bright fluorescent dyes, a number of approaches now exploit chemical or environmental changes to control the properties of a bound dye, converting dyes from a weakly fluorescent state to a bright, easily detectable complex. Optimized, such approaches avoid the need for removal of unbound dyes, facilitate rapid and simple assays in cultured cells and enable hybrid labeling to function more robustly in living model organisms.
Collapse
Affiliation(s)
- Marcel P Bruchez
- Molecular Biosensor and Imaging Center, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA; Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA; Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA.
| |
Collapse
|
10
|
Yapici I, Lee KSS, Berbasova T, Nosrati M, Jia X, Vasileiou C, Wang W, Santos EM, Geiger JH, Borhan B. "Turn-on" protein fluorescence: in situ formation of cyanine dyes. J Am Chem Soc 2015; 137:1073-80. [PMID: 25534273 PMCID: PMC4311949 DOI: 10.1021/ja506376j] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Protein reengineering of cellular retinoic acid binding protein II (CRABPII) has yielded a genetically addressable system, capable of binding a profluorophoric chromophore that results in fluorescent protein/chromophore complexes. These complexes exhibit far-red emission, with high quantum efficiencies and brightness and also exhibit excellent pH stability spanning the range of 2-11. In the course of this study, it became evident that single mutations of L121E and R59W were most effective in improving the fluorescent characteristics of CRABPII mutants as well as the kinetics of complex formation. The readily crystallizable nature of these proteins was invaluable to provide clues for the observed spectroscopic behavior that results from single mutation of key residues.
Collapse
Affiliation(s)
- Ipek Yapici
- Department of Chemistry, Michigan State University , East Lansing, Michigan 48824, United States
| | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Fisher GW, Fuhrman MH, Adler SA, Szent-Gyorgyi C, Waggoner AS, Jarvik JW. Self-Checking Cell-Based Assays for GPCR Desensitization and Resensitization. ACTA ACUST UNITED AC 2014; 19:1220-6. [DOI: 10.1177/1087057114534299] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 04/09/2014] [Indexed: 11/15/2022]
Abstract
G protein–coupled receptors (GPCRs) play stimulatory or modulatory roles in numerous physiological states and processes, including growth and development, vision, taste and olfaction, behavior and learning, emotion and mood, inflammation, and autonomic functions such as blood pressure, heart rate, and digestion. GPCRs constitute the largest protein superfamily in the human and are the largest target class for prescription drugs, yet most are poorly characterized, and of the more than 350 nonolfactory human GPCRs, over 100 are orphans for which no endogenous ligand has yet been convincingly identified. We here describe new live-cell assays that use recombinant GPCRs to quantify two general features of GPCR cell biology—receptor desensitization and resensitization. The assays employ a fluorogen-activating protein (FAP) reporter that reversibly complexes with either of two soluble organic molecules (fluorogens) whose fluorescence is strongly enhanced when complexed with the FAP. Both assays require no wash or cleanup steps and are readily performed in microwell plates, making them adaptable to high-throughput drug discovery applications.
Collapse
Affiliation(s)
- Gregory W. Fisher
- Department of Biological Sciences and Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Margaret H. Fuhrman
- Department of Biological Sciences and Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Sally A. Adler
- Department of Biological Sciences and Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Christopher Szent-Gyorgyi
- Department of Biological Sciences and Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Alan S. Waggoner
- Department of Biological Sciences and Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Jonathan W. Jarvik
- Department of Biological Sciences and Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, PA, USA
| |
Collapse
|
12
|
Gallo E, Vasilev KV, Jarvik J. Fluorogen-activating-proteins as universal affinity biosensors for immunodetection. Biotechnol Bioeng 2014; 111:475-84. [PMID: 24122476 PMCID: PMC4334571 DOI: 10.1002/bit.25127] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 09/13/2013] [Accepted: 10/02/2013] [Indexed: 11/11/2022]
Abstract
Fluorogen-activating-proteins (FAPs) are a novel platform of fluorescence biosensors utilized for protein discovery. The technology currently demands molecular manipulation methods that limit its application and adaptability. Here, we highlight an alternative approach based on universal affinity reagents for protein detection. The affinity reagents were engineered as bi-partite fusion proteins, where the specificity moiety is derived from IgG-binding proteins-Protein A or Protein G-and the signaling element is a FAP. In this manner, primary antibodies provide the antigenic selectivity against a desired protein in biological samples, while FAP affinity reagents target the constant region (Fc) of antibodies and provide the biosensor component of detection. Fluorescence results using various techniques indicate minimal background and high target specificity for exogenous and endogenous proteins in mammalian cells. Additionally, FAP-based affinity reagents provide enhanced properties of detection previously absent using conventional affinity systems. Distinct features explored in this report include: (1) unfixed signal wavelengths (excitation and emission) determined by the particular fluorogen chosen, (2) real-time user controlled fluorescence on-set and off-set, (3) signal wavelength substitution while performing live analysis, and (4) enhanced resistance to photobleaching.
Collapse
Affiliation(s)
- Eugenio Gallo
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA 15213
| | - Kalin V. Vasilev
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA 15213
| | - Jonathan Jarvik
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA 15213
- Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA 15213
| |
Collapse
|
13
|
Fluorogen-Activating scFv Biosensors Target Surface Markers on Live Cells Via Streptavidin or Single-Chain Avidin. Mol Biotechnol 2014; 56:585-90. [DOI: 10.1007/s12033-014-9732-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
14
|
Induction of HIV-blocking anti-CCR5 IgA in Peyers's patches without histopathological alterations. J Virol 2014; 88:3623-35. [PMID: 24403594 DOI: 10.1128/jvi.03663-13] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
UNLABELLED The chemokine receptor CCR5 is essential for HIV infection and is thus a potential target for vaccine development. However, because CCR5 is a host protein, generation of anti-CCR5 antibodies requires the breaking of immune tolerance and thus carries the risk of autoimmune responses. In this study, performed in mice, we compared 3 different immunogens representing surface domains of murine CCR5, 4 different adjuvants, and 13 different immunization protocols, with the goal of eliciting HIV-blocking activity without inducing autoimmune dysfunction. In all cases the CCR5 sequences were presented as fusions to the Flock House virus (FHV) capsid precursor protein. We found that systemic immunization and mucosal boosting elicited CCR5-specific antibodies and achieved consistent priming in Peyer's patches, where most cells showed a phenotype corresponding to activated B cells and secreted high levels of IgA, representing up to one-third of the total HIV-blocking activity. Histopathological analysis revealed mild to moderate chronic inflammation in some tissues but failed in reporting signs of autoimmune dysfunction associated with immunizations. Antisera against immunogens representing the N terminus and extracellular loops 1 and 2 (Nter1 and ECL1 and ECL2) of CCR5 were generated. All showed specific anti-HIV activity, which was stronger in the anti-ECL1 and -ECL2 sera than in the anti-Nter sera. ECL1 and ECL2 antisera induced nearly complete long-lasting CCR5 downregulation of the receptor, and especially, their IgG-depleted fractions prevented HIV infection in neutralization and transcytosis assays. In conclusion, the ECL1 and ECL2 domains could offer a promising path to achieve significant anti-HIV activity in vivo. IMPORTANCE The study was the first to adopt a systematic strategy to compare the immunogenicities of all extracellular domains of the CCR5 molecule and to set optimal conditions leading to generation of specific antibodies in the mouse model. There were several relevant findings, which could be translated into human trials. (i) Prime (systemic) and boost (mucosal) immunization is the best protocol to induce anti-self antibodies with the expected properties. (ii) Aluminum is the best adjuvant in mice and thus can be easily used in nonhuman primates (NHP) and humans. (iii) The Flock House virus (FHV) system represents a valid delivery system, as the structure is well known and is not pathogenic for humans, and it is possible to introduce constrained regions able to elicit antibodies that recognize conformational epitopes. (iv) The best CCR5 vaccine candidate should include either extracellular loop 1 or 2 (ECL1 or ECL2), but not N terminus domains.
Collapse
|
15
|
Wu Y, Tapia PH, Jarvik J, Waggoner AS, Sklar LA. Real-time detection of protein trafficking with high-throughput flow cytometry (HTFC) and fluorogen-activating protein (FAP) base biosensor. ACTA ACUST UNITED AC 2014; 67:9.43.1-9.43.11. [PMID: 24510772 DOI: 10.1002/0471142956.cy0943s67] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We combined fluorogen-activating protein (FAP) technology with high-throughput flow cytometry to detect real-time protein trafficking to and from the plasma membrane in living cells. The hybrid platform allows drug discovery for trafficking receptors, such as G protein-coupled receptors, receptor tyrosine kinases, and ion channels, which were previously not suitable for high-throughput screening by flow cytometry. The system has been validated using the β2-adrenergic receptor (β2AR) system and extended to other GPCRs. When a chemical library containing ∼ 1200 off-patent drugs was screened against cells expressing FAP-tagged β2AR, all known β2AR active ligands in the library were successfully identified, together with a few compounds that were later confirmed to regulate receptor internalization in a nontraditional manner. The unexpected discovery of new ligands by this approach indicates the potential of using this protocol for GPCR de-orphanization. In addition, screens of multiplexed targets promise improved efficiency with minor protocol modification.
Collapse
Affiliation(s)
- Yang Wu
- Center for Molecular Discovery, University of New Mexico School of Medicine, Albuquerque, New Mexico.,Department of Pathology, University of New Mexico School of Medicine, Albuquerque, New Mexico
| | - Phillip H Tapia
- Center for Molecular Discovery, University of New Mexico School of Medicine, Albuquerque, New Mexico
| | - Jonathan Jarvik
- Department of Biological Sciences, Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Alan S Waggoner
- Department of Biological Sciences, Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Larry A Sklar
- Center for Molecular Discovery, University of New Mexico School of Medicine, Albuquerque, New Mexico.,Department of Pathology, University of New Mexico School of Medicine, Albuquerque, New Mexico
| |
Collapse
|