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Matsunaga S, Masaoka T, Sawasaki T, Morishita R, Iwatani Y, Tatsumi M, Endo Y, Yamamoto N, Sugiura W, Ryo A. A cell-free enzymatic activity assay for the evaluation of HIV-1 drug resistance to protease inhibitors. Front Microbiol 2015; 6:1220. [PMID: 26583013 PMCID: PMC4628118 DOI: 10.3389/fmicb.2015.01220] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 10/19/2015] [Indexed: 12/27/2022] Open
Abstract
Due to their high frequency of genomic mutations, human retroviruses often develop resistance to antiretroviral drugs. The emergence of drug-resistant human immunodeficiency virus type 1 (HIV-1) is a significant obstacle to the effective long-term treatment of HIV infection. The development of a rapid and versatile drug-susceptibility assay would enable acquisition of phenotypic information and facilitate determination of the appropriate choice of antiretroviral agents. In this study, we developed a novel in vitro method, termed the Cell-free drug susceptibility assay (CFDSA), for monitoring phenotypic information regarding the drug resistance of HIV-1 protease (PR). The CFDSA utilizes a wheat germ cell-free protein production system to synthesize enzymatically active HIV-1 PRs directly from PCR products amplified from HIV-1 molecular clones or clinical isolates in a rapid one-step procedure. Enzymatic activity of PRs can be readily measured by AlphaScreen (Amplified Luminescent Proximity Homogeneous Assay Screen) in the presence or absence of clinically used protease inhibitors (PIs). CFDSA measurement of drug resistance was based on the fold resistance to the half-maximal inhibitory concentration (IC50) of various PIs. The CFDSA could serve as a non-infectious, rapid, accessible, and reliable alternative to infectious cell-based phenotypic assays for evaluation of PI-resistant HIV-1.
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Affiliation(s)
- Satoko Matsunaga
- Department of Microbiology, School of Medicine, Yokohama City University Yokohama, Japan
| | - Takashi Masaoka
- Department of Infection and Immunology, Clinical Research Center, National Hospital Organization Nagoya Medical Center Nagoya, Japan
| | | | - Ryo Morishita
- Department of Microbiology, School of Medicine, Yokohama City University Yokohama, Japan ; CellFree Sciences Co., Ltd. Matsuyama, Japan
| | - Yasumasa Iwatani
- Department of Infection and Immunology, Clinical Research Center, National Hospital Organization Nagoya Medical Center Nagoya, Japan ; Department of AIDS Research, Nagoya University Graduate School of Medicine Nagoya, Japan
| | - Masashi Tatsumi
- Department of AIDS Research, AIDS Research Center, National Institute of Infectious Diseases Tokyo, Japan
| | - Yaeta Endo
- Proteo-Science Center, Ehime University Matsuyama, Japan
| | - Naoki Yamamoto
- Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore Singapore, Singapore
| | - Wataru Sugiura
- Department of Infection and Immunology, Clinical Research Center, National Hospital Organization Nagoya Medical Center Nagoya, Japan ; Department of AIDS Research, Nagoya University Graduate School of Medicine Nagoya, Japan
| | - Akihide Ryo
- Department of Microbiology, School of Medicine, Yokohama City University Yokohama, Japan
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2
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Yoon HK, Yoo TH. A novel protease activity assay method based on an engineered autoinhibited protein using an enzyme-linked immunoassay. Analyst 2013; 138:7164-8. [DOI: 10.1039/c3an01336g] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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3
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Welser K, Adsley R, Moore BM, Chan WC, Aylott JW. Protease sensing with nanoparticle based platforms. Analyst 2010; 136:29-41. [PMID: 20877821 DOI: 10.1039/c0an00429d] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Nanoparticulate systems in various unique configurations are highly effective at detecting protease activity both in vivo and in vitro. In this article, we have summarised the conventional modern methods for monitoring protease activity, and critically appraised recent advances in protease-responsive nanosensors.
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Affiliation(s)
- Katharina Welser
- School of Pharmacy, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham, UK NG7 2RD
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4
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Clé C, Martin C, Field RA, Kuzmič P, Bornemann S. Detection of enzyme-catalyzed polysaccharide synthesis on surfaces. BIOCATAL BIOTRANSFOR 2009. [DOI: 10.3109/10242420903388744] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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5
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Iga M, Matsuda Z, Okayama A, Sugiura W, Hashida S, Morishita K, Nagai Y, Tsubouchi H. Rapid phenotypic assay for human immunodeficiency virus type 1 protease using in vitro translation. J Virol Methods 2002; 106:25-37. [PMID: 12367727 DOI: 10.1016/s0166-0934(02)00133-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A rapid in vitro phenotyping method for human immunodeficiency virus type 1 (HIV-1) protease was developed. In this system, both HIV-1 protease and substrates are prepared using a rabbit reticulocyte based coupled in vitro transcription/translation system. The activity of protease is evaluated by the amount of cleaved substrate measured by ELISA. In this system, wild-type protease derived from strain HXB2 was specifically inhibited in a dose-dependent manner by the protease inhibitors, indinavir and nelfinavir. Three drug-resistant proteases carrying a single mutation, D30N, L90M, and V82F, were analyzed in the absence of the inhibitors. Reflecting their impaired fitness, they exhibited decreased protease activity compared with the wild type. The apparent protease activity was greater for a Gag-Pol substrate encompassing the Gag-protease-reverse transcriptase junctions than for a substrate only covering the Gag region. Using the Gag-Pol substrate as the target, the indinavir-resistant mutant V82F was evaluated further. V82F showed 9-fold resistance to its cognitive protease inhibitor, indinavir; however, it manifested only moderate (2-fold) resistance to a non-cognitive inhibitor, nelfinavir. This simple and rapid method may be useful for phenotyping of drug-resistant HIV-1 protease as well as for screening new inhibitors of HIV-1 protease.
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Affiliation(s)
- Mutsunori Iga
- Department of Internal Medicine II, Miyazaki Medical College, 5200 Kihara, Kiyotake, Miyazaki 889-1601, Japan
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6
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Gutiérrez OA, Salas E, Hernández Y, Lissi EA, Castrillo G, Reyes O, Garay H, Aguilar A, García B, Otero A, Chavez MA, Duarte CA. An immunoenzymatic solid-phase assay for quantitative determination of HIV-1 protease activity. Anal Biochem 2002; 307:18-24. [PMID: 12137774 DOI: 10.1016/s0003-2697(02)00009-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A novel immunoenzymatic procedure for the quantitative determination of HIV protease activity is provided. An N-terminal biotinylated peptide (DU1) that comprises an HIV-1 protease (HIV-PR) cleavage sequence was bound to streptavidin-coated microtiter plates. The bound peptide can be quantified by an immunoenzymatic procedure (enzyme-linked immunosorbent assay, ELISA) that includes a monoclonal antibody (Mab 332) against the peptide (DU1) C-terminal. The incubation of the bound peptide with HIV-PR in solution resulted in a signal decrement, as the peptide was hydrolyzed and the released C-terminal segment washed away. An equation that relates the amount of added enzyme to the kinetics of the reaction was written in order to describe this heterogeneous enzyme-quasi-saturable system. This equation allows quantitative determination of protease activity, a feature widely underrated in previous similar assays. The assay also allows evaluation of the inhibitory activity of HIV-PR inhibitors. Due to the intrinsic advantages of the ELISA format, this method could be used in high-throughput screening of HIV protease inhibitors. The assay can be extended to other proteolytic enzymes.
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Affiliation(s)
- Omar A Gutiérrez
- Facultad de Biología, Centro de Estudios de la Proteínas, Universidad de la Habana, Ciudad Habana, Cuba.
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7
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Tai HY, Sun KH, Kung SH, Liu WT. A quantitative assay for measuring human foamy virus using an established indicator cell line. J Virol Methods 2001; 94:155-62. [PMID: 11337050 DOI: 10.1016/s0166-0934(01)00285-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
In order to improve the accuracy for detecting human foamy virus (HFV), an indicator cell line was established by co-transfecting baby hamster kidney-21 cells with two plasmids: one containing a G418 antibiotic resistance marker and the other including the luc gene which was placed downstream of the inducible HFV long terminal repeat promoter (from -533 to +20). Among 11 independent subclones, IdB14 was found to be stable with a low basal level of luciferase activity. Although the changes in luciferase activity in infected clones showed time-dependency and peaked at day 8, it is possible to differentiate infected and uninfected cells on day 2. The sensitivity of the foamy virus activated luciferase (FAL) assay was 400 times higher than the end-point syncytium formation by TCID(50). The HFV LTR promoter in the IdB14 cell line was specific for this virus. Moreover, a linear relationship was found between the MOI and the activated intensity of luciferase expression. These findings suggest that the FAL assay using the IdB14 indicator cell line is a simple and useful technique for rapid diagnosis and quantitation of active HFV infection.
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Affiliation(s)
- H Y Tai
- Institute of Biotechnology in Medicine, School of Medical Technology and Engineering, National Yang-Ming University, 155 Section 2, Lie-Nong Street, 112, Taipei, Taiwan, ROC
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8
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Chang YY, Yu SL, Syu WJ. Organization of HIV-1 pol is critical for Pol polyprotein processing. J Biomed Sci 1999; 6:333-41. [PMID: 10494040 DOI: 10.1007/bf02253522] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The HIV pol sequentially encodes protease (PR), reverse transcriptase (RT), and integrase (IN) from the 5'-3' direction. We explored the significance of this gene arrangement. All six possible gene dispositions were examined. In two situations where PR was removed from the leading place and no two genes were in their original location, viral polyprotein processing was abolished. Processing of the polyprotein did not occur when IN was translocated to the front of PR-RT. However, in the following two arrangements, the polyprotein was processed but only at specific sites. First, PR remained in the leading position while the locations of RT and IN were exchanged; viral polyprotein was processed at a site between the upstream transframe peptide (TF) and PR. Second, PR was placed after RT-IN and located at the distal end of Pol. Processing occurred only at the created junction between TF and RT. These results indicated that cleavage after TF occurred autocatalytically but did not proceed to a second site, which needed an extraneous PR for trans-action. Therefore, arranging Pol in the order of PR-RT-IN warrants the streamline processing of the polyprotein once the autocleavage is initiated.
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Affiliation(s)
- Y Y Chang
- Institute of Microbiology and Immunology, National Yang Ming University, Taipei, Taiwan, ROC
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Tan XD, Hsueh W, Chang H, Wei KR, Gonzalez-Crussi F. Characterization of a putative receptor for intestinal trefoil factor in rat small intestine: identification by in situ binding and ligand blotting. Biochem Biophys Res Commun 1997; 237:673-7. [PMID: 9299425 DOI: 10.1006/bbrc.1997.7144] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Intestinal trefoil factor (ITF), a small peptide secreted by intestinal goblet cells, maintains mucosal integrity and promotes epithelial wound healing. Although ITF has been cloned, the detailed mechanism by which ITF interacts with intestinal epithelium remains elusive. In the present study, we expressed mature rat ITF (rITF) with pXa (a prokaryotic expression vector) in Escherichia coli to generate a biotinylated rITF fusion protein (bTag-ITF). By using bTag-ITF probe, we identified ITF binding cells in the crypts of the small intestine and mucous cells of the region of gastric glands. Using a ligand blotting technique, we further characterized a 50 kDa glycosylated protein from the membrane fraction of the small intestine, which bound to bTag-ITF. Our data suggest that this 50 kDa membrane glycoprotein is a putative receptor for ITF in the gastrointestinal tract.
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Affiliation(s)
- X D Tan
- Department of Pathology, Children's Memorial Hospital, Northwestern University, Chicago, Illinois 60614, USA.
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10
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Abstract
Integration of reverse transcribed viral DNA of HIV into host chromosomes is mediated by the viral enzyme, integrase. This enzymatic activity can be monitored in vitro by integration of a small labeled DNA (donor) into a second unlabeled DNA (target). The methodology usually involves isotope labeling and gel electrophoresis. To simplify the measurement, a method mimicking enzyme-linked immunosorbent assay (ELISA) procedures was developed. Fragments of DNA were adsorbed directly on 96-well plates and used as the target DNA. The donor was a synthetic 21-bp DNA duplex of HIV-1 U5 LTR; biotin was incorporated into the 5' end of one strand whose two nucleotides at the 3' end were specifically removed during the integration. As a result of integration, the biotin-labeled donor DNA was joined with the target DNA and became immobilized on plates. These integration products were then measured by binding of avidin-alkaline phosphatase on plates. The method is simple and straightforward and can easily be adapted for high throughput screening of integrase inhibitors.
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Affiliation(s)
- Y C Chang
- Institute of Microbiology and Immunology, National Yang-Ming University, Taiwan, ROC
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