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Gaur NK, Urankar S, Sengupta D, Chepuri VR, Makde RD, Kulkarni K. A cell based assay using virus-like particles to screen AM type mimics for SARS-CoV-2 neutralisation. Biochem Biophys Res Commun 2024; 718:150082. [PMID: 38735141 DOI: 10.1016/j.bbrc.2024.150082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2024] [Accepted: 05/07/2024] [Indexed: 05/14/2024]
Abstract
A number of small molecule and protein therapeutic candidates have been developed in the last four years against SARS-CoV-2 spike. However, there are hardly a few molecules that have advanced through the subsequent discovery steps to eventually work as a therapeutic agent. This is majorly because of the hurdles in determining the affinity of potential therapeutics with live SARS-CoV-2 virus. Furthermore, affinity determined for the receptor binding domain (RBD) of the SARS-CoV-2 spike protein, at times, fails to mimic physiological conditions of the host-virus interaction. To bridge this gap between in vitro and in vivo methods of therapeutic agent screening, we report an improved screening protocol for therapeutic candidates using SARS-CoV-2 virus like particles (VLPs). To minimise the interference from the bulkier reporters like GPF in the affinity studies, a smaller hemagglutinin (HA) tag has been fused to one of the proteins of VLP. This HA tag serves as readout, when probed with fluorescent anti-HA antibodies. Outcome of this study sheds light on the lesser known virus neutralisation capabilities of AM type miniprotein mimics. Further, to assess the stability of SARS-CoV-2 spike - miniprotein complex, we have performed molecular dynamic simulations on the membrane embedded protein complex. Simulation results reveal extremely stable intermolecular interactions between RBD and one of the AM type miniproteins, AM1. Furthermore, we discovered a robust network of intramolecular interactions that help stabilise AM1. Findings from our in vitro and in silico experiments concurrently highlight advantages and capabilities of mimic based miniprotein therapeutics.
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Affiliation(s)
- Neeraj Kailash Gaur
- Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune- 411008, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad- 201002, India
| | - Shreegauri Urankar
- Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune- 411008, India
| | - Durba Sengupta
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad- 201002, India; Division of Physical and Material Chemistry, CSIR- National Chemical Laboratory, Pune, 411008, India
| | - V Ramana Chepuri
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad- 201002, India; Division of Organic Chemistry, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 411 008, India
| | - Ravindra D Makde
- Beamline Development and Application Section, Bhabha Atomic Research Centre, Mumbai, India
| | - Kiran Kulkarni
- Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune- 411008, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad- 201002, India.
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Du Pasquier D, Salinier B, Coady KK, Jones A, Körner O, LaRocca J, Lemkine G, Robin-Duchesne B, Weltje L, Wheeler JR, Lagadic L. How the Xenopus eleutheroembryonic thyroid assay compares to the amphibian metamorphosis assay for detecting thyroid active chemicals. Regul Toxicol Pharmacol 2024; 149:105619. [PMID: 38614220 DOI: 10.1016/j.yrtph.2024.105619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 02/05/2024] [Accepted: 04/03/2024] [Indexed: 04/15/2024]
Abstract
The Xenopus Eleutheroembryonic Thyroid Assay (XETA) was recently published as an OECD Test Guideline for detecting chemicals acting on the thyroid axis. However, the OECD validation did not cover all mechanisms that can potentially be detected by the XETA. This study was therefore initiated to investigate and consolidate the applicability domain of the XETA regarding the following mechanisms: thyroid hormone receptor (THR) agonism, sodium-iodide symporter (NIS) inhibition, thyroperoxidase (TPO) inhibition, deiodinase (DIO) inhibition, glucocorticoid receptor (GR) agonism, and uridine 5'-diphospho-glucuronosyltransferase (UDPGT) induction. In total, 22 chemicals identified as thyroid-active or -inactive in Amphibian Metamorphosis Assays (AMAs) were tested using the XETA OECD Test Guideline. The comparison showed that both assays are highly concordant in identifying chemicals with mechanisms of action related to THR agonism, DIO inhibition, and GR agonism. They also consistently identified the UDPGT inducers as thyroid inactive. NIS inhibition, investigated using sodium perchlorate, was not detected in the XETA. TPO inhibition requires further mechanistic investigations as the reference chemicals tested resulted in opposing response directions in the XETA and AMA. This study contributes refining the applicability domain of the XETA, thereby helping to clarify the conditions where it can be used as an ethical alternative to the AMA.
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Affiliation(s)
- David Du Pasquier
- Laboratoire WatchFrog, 1 Rue Pierre Fontaine, 91000, Évry-Courcouronnes, France
| | - Benoît Salinier
- Laboratoire WatchFrog, 1 Rue Pierre Fontaine, 91000, Évry-Courcouronnes, France
| | - Katherine K Coady
- Bayer Crop Science, Environmental Safety, 700 Chesterfield Parkway West, Chesterfield, MO, USA
| | - Alan Jones
- ADAMA US, Environmental Safety, 3120 Highwoods Blvd., Raleigh, NC, 27604, USA
| | - Oliver Körner
- ADAMA, Environmental Safety, Edmund-Rumpler-Strasse 6, 51149, Cologne, Germany
| | - Jessica LaRocca
- Corteva Agriscience, 9330 Zionsville Road, Indianapolis, IN, 46268, USA
| | - Gregory Lemkine
- Laboratoire WatchFrog, 1 Rue Pierre Fontaine, 91000, Évry-Courcouronnes, France
| | | | - Lennart Weltje
- BASF SE, Agricultural Solutions - Ecotoxicology, Speyerer Strasse 2, 67117, Limburgerhof, Germany
| | - James R Wheeler
- Corteva Agriscience, Zuid-Oostsingel 24D, 4611 BB, Bergen op Zoom, the Netherlands
| | - Laurent Lagadic
- Bayer AG R&D Crop Science, Alfred-Nobel-Strasse 50, 40789, Monheim am Rhein, Germany.
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Ma L, Li Q, Xie Y, Jianyuan Zhao, Yi D, Guo S, Guo F, Wang J, Yang L, Cen S. Repurposing of HIV/HCV protease inhibitors against SARS-CoV-2 3CL pro. Antiviral Res 2022; 207:105419. [PMID: 36155070 PMCID: PMC9499987 DOI: 10.1016/j.antiviral.2022.105419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 08/18/2022] [Accepted: 09/12/2022] [Indexed: 11/29/2022]
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the pathogen that caused the global COVID-19 outbreak. The 3C-like protease (3CLpro) of SARS-CoV-2 plays a key role in virus replication and has become an ideal target for antiviral drug design. In this work, we have employed bioluminescence resonance energy transfer (BRET) technology to establish a cell-based assay for screening inhibitors against SARS-CoV-2 3CLpro, and then applied the assay to screen a collection of known HIV/HCV protease inhibitors. Our results showed that the assay is capable of quantification of the cleavage efficiency of 3CLpro with good reproducibility (Z' factor is 0.59). Using the assay, we found that 9 of 26 protease inhibitors effectively inhibited the activity of SARS-CoV-2 3CLpro in a dose-dependent manner. Among them, four compounds exhibited the ability to bind to 3CLproin vitro. HCV protease inhibitor simeprevir showed the most potency against 3CLpro with an EC50 vale of 2.6 μM, bound to the active site pocket of 3CLpro in a predicted model, and importantly, exhibited a similar activity against the protease containing the mutations P132H in Omicron variants. Taken together, this work demonstrates the feasibility of using the cell-based BRET assay for screening 3CLpro inhibitors and supports the potential of simeprevir for the development of 3CLpro inhibitors.
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Affiliation(s)
- Ling Ma
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Science, Beijing, China
| | - Quanjie Li
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Science, Beijing, China
| | - Yongli Xie
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Science, Beijing, China
| | - Jianyuan Zhao
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Science, Beijing, China
| | - Dongrong Yi
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Science, Beijing, China
| | - Saisai Guo
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Science, Beijing, China
| | - Fei Guo
- Institute of Pathogen Biology, Chinese Academy of Medical Science, Beijing, China
| | - Jing Wang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Science, Beijing, China.
| | - Long Yang
- School of Integrative Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, 301617, China.
| | - Shan Cen
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Science, Beijing, China.
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4
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Jasim RK, Singh D, Gam LH. Development and validation of ELISA for screening of Kratom (Mitragyna speciosa) habitual users using urinary AZ122 biomarker. Biotechnol Appl Biochem 2022; 70:707-715. [PMID: 35931067 DOI: 10.1002/bab.2392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 07/22/2022] [Indexed: 11/07/2022]
Abstract
Background Kratom (Mitragyna speciosa korth), has been used traditionally in Southeast Asia for its therapeutic properties. The major alkaloid of kratom, mitragynine binds to opioid receptors to give opioid-like effects that causes addiction. In our previous study, we have identified AZ122 as a unique biomarker in habitual or regular kratom users through analysis of their urinary protein profiles. We aimed to develop and validate a screening method by means of ELISA for detection of kratom habitual users. Methods An ELISA approach was applied for the development of a screening method using urinary AZ122 as biomarker. Method validation was carried out using 3 QC materials at different concentration of AZ122. The data was analyzed statistically using SPSS (Version 25). Results The ELISA was presented with Pearson correlation coefficient of 0.9993. The repeatability and reproducibility were presented at CV <7%, while the accuracy ranged from 78% to 96% at various AZ112 concentrations. Upon testing on 176 male respondents (n = 88 regular kratom users, and n = 88 healthy controls), the specificity and sensitivity of the assay were both 100%. Conclusions The ELISA has been validated and can be potentially used as a reliable screening test for detection of kratom habitual users.
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Affiliation(s)
- Rana Khudhair Jasim
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, Penang, 11800, Malaysia
| | - Darshan Singh
- Centre of Drug Research, Universiti Sains Malaysia, Penang, 11800, Malaysia
| | - Lay-Harn Gam
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, Penang, 11800, Malaysia
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Ximenes IAT, Albino M, Sangregorio C, Cass QB, de Moraes MC. On-flow magnetic particle activity assay for the screening of human purine nucleoside phosphorylase inhibitors. J Chromatogr A 2021; 1663:462740. [PMID: 34942489 DOI: 10.1016/j.chroma.2021.462740] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 12/02/2021] [Accepted: 12/05/2021] [Indexed: 12/13/2022]
Abstract
Human purine nucleoside phosphorylase (HsPNP) catalyzes reversible phosphorolysis of nucleosides and deoxynucleosides in the purine cascade. HsPNP has been a target on behalf of the development of new leads for the treatment of a variety of T-cell mediated disorders. Several studies on the HsPNP are focused on the identification of effective, safe, and selective inhibitors. Therefore, this study describes the development of direct, simple, reliable, and inexpensive enzymatic assays to screen HsPNP inhibitors. Initially, HsPNP was covalently immobilized on the surface of magnetic particles (MPs). Due to the versatility of the MPs as solid support for enzyme immobilization, two different methods to monitor the enzyme activity are presented. Firstly, the activity of HsPNP-MPs was assessed offline by HPLC-DAD quantifying the formed hypoxanthine. Then, HsPNP-MPs were trapped in a peek tube, furnishing a microreactor which was inserted on-flow in an HPLC-DAD system to monitor the enzyme activity by the hypoxanthine quantification. Kinetic assays provided KMapp values for the inosine substrate of 488.2 ± 49.1 and 1084 ± 111 µM for the offline and on-flow assays, respectively. For the first time, kinetic studies for Pi as substrate using the HsPNP-MPs exhibits a Michaelis-Menten kinetic, yielding KMapp values for offline and on-flow of 521.2 ± 62.9 µM and 601 ± 66.5 µM, respectively. Inhibition studies conducted with a fourth generation immucillin derivative (DI4G) were employed as proof of concept to validate the use of the HsPNP-MPs assays for screening purposes. Additionally, a small library containing 11 compounds was used to assess the selectivity of the developed assays. The results showed that both presented assays can be applied to selectively recognizing and characterizing HsPNP inhibitors. Particularly, the on-flow method exhibited a high throughput and performance because of its automation and represents an easy and practical approach to reuse the HsPNP-MPs. Besides, this novel enzyme activity assay model can be further applied to other biological targets.
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Affiliation(s)
- I A T Ximenes
- Instituto de Química, Universidade Federal Fluminense. Niterói, Rio de Janeiro, 24020-141, Brazil
| | - M Albino
- INSTM and Dept. of Chemistry "Ugo Schiff", University of Florence, via della Lastruccia 3, 50019 Sesto Fiorentino, Italy
| | - C Sangregorio
- INSTM and Dept. of Chemistry "Ugo Schiff", University of Florence, via della Lastruccia 3, 50019 Sesto Fiorentino, Italy; ICCOM-CNR, via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy
| | - Q B Cass
- SEPARARE - Núcleo de Pesquisa em Cromatografia, Department of Chemistry, Federal University of São Carlos, Rod. Washington Luiz, Km 235, São Carlos, SP, Brazil
| | - M C de Moraes
- Instituto de Química, Universidade Federal Fluminense. Niterói, Rio de Janeiro, 24020-141, Brazil.
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Medan J, Sleebs BE, Lackovic K, Watson KG, Evison BJ, Phillips DR, Cutts SM. Development of an automated assay for accelerated in vitro detection of DNA adduct-inducing and crosslinking agents. Bioorg Med Chem Lett 2021; 35:127813. [PMID: 33486050 DOI: 10.1016/j.bmcl.2021.127813] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 12/21/2020] [Accepted: 01/17/2021] [Indexed: 10/22/2022]
Abstract
Current techniques for the identification of DNA adduct-inducing and DNA interstrand crosslinking agents include electrophoretic crosslinking assays, electrophoretic gel shift assays, DNA and RNA stop assays, mass spectrometry-based methods and 32P-post-labelling. While these assays provide considerable insight into the site and stability of the interaction, they are relatively expensive, time-consuming and sometimes rely on the use of radioactively-labelled components, and thus are ill-suited to screening large numbers of compounds. A novel medium throughput assay was developed to overcome these limitations and was based on the attachment of a biotin-tagged double stranded (ds) oligonucleotide to Corning DNA-Bind plates. We aimed to detect anthracycline and anthracenedione DNA adducts which form by initial non-covalent intercalation with duplex DNA, and subsequent covalent adduct formation which is mediated by formaldehyde. Following drug treatment, DNA samples were subjected to a denaturation step, washing and then measurement by fluorescence to detect remaining drug-DNA species using streptavidin-europium. This dissociation-enhanced lanthanide fluorescent immunoassay (DELFIA) is a time-resolved fluorescence intensity assay where the fluorescence signal arises only from stabilised drug-DNA complexes. We applied this new methodology to the identification of anthracycline-like compounds with the ability to functionally crosslink double-strand oligonucleotides. The entire procedure can be performed by robotics, requiring low volumes of compounds and reagents, thereby reducing costs and enabling multiple compounds to be assessed on a single microtitre plate.
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Affiliation(s)
- Jelena Medan
- La Trobe Institute for Molecular Science, La Trobe University, Victoria 3086, Australia; Walter and Eliza Hall Institute, Parkville, Victoria 3052, Australia
| | - Brad E Sleebs
- Walter and Eliza Hall Institute, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Kurt Lackovic
- Walter and Eliza Hall Institute, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia; Cancer Trials Australia, Melbourne, Victoria 3000, Australia
| | - Keith G Watson
- Walter and Eliza Hall Institute, Parkville, Victoria 3052, Australia
| | - Benny J Evison
- La Trobe Institute for Molecular Science, La Trobe University, Victoria 3086, Australia; Nyrada Inc, 828 Pacific Highway, Gordon, NSW 2072, Australia
| | - Don R Phillips
- La Trobe Institute for Molecular Science, La Trobe University, Victoria 3086, Australia
| | - Suzanne M Cutts
- La Trobe Institute for Molecular Science, La Trobe University, Victoria 3086, Australia.
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7
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Godelaine J, Bossuyt X, Poesen K. The clinical significance of atypical indirect immunofluorescence patterns on primate cerebellum in paraneoplastic antibody screening. Auto Immun Highlights 2020; 10:6. [PMID: 32257062 PMCID: PMC7065332 DOI: 10.1186/s13317-019-0116-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 07/12/2019] [Indexed: 11/25/2022]
Abstract
Purpose Screening for paraneoplastic antibodies is often performed by means of indirect immunofluorescence on primate cerebellar slices. However, atypical immunofluorescence patterns, i.e. patterns that are not specifically related to paraneoplastic antibodies, are often reported. The clinical significance of these patterns is not clear. Therefore, the purpose of this study was to determine the significance and diagnostic value—in terms of a paraneoplastic neurological syndrome or other neurological disease being diagnosed in the patient—of such atypical immunofluorescence screening patterns on primate cerebellum. Methods This study is a retrospective single center study including atypical indirect immunofluorescence screening patterns of patients with a negative or absent typing assay for intraneuronal and anti-amphiphysin paraneoplastic antibodies. Patients with a positive typing assay or without final diagnosis were excluded. Included patients were grouped according to (i) reported immunofluorescence pattern and (ii) established diagnosis, after which contingency table analyses were performed to investigate an interrelation between reported pattern and diagnostic group. Results In 3.7% of cases, patients with an atypical pattern obtained a final diagnosis of a paraneoplastic neurological syndrome. The presence of atypical patterns was more prominent in patients with epilepsy or peripheral neuropathies (pMonte Carlo simulation= 0.026), without, however, adding any diagnostic information. Conclusions An atypical indirect immunofluorescence pattern on primate cerebellum in the screening for paraneoplastic antibodies has only very minor relevance with respect to paraneoplastic neurological syndromes or any other neurological disease, recommending clinicians to interpret the results of positive screening assays for such antibodies with care. Electronic supplementary material The online version of this article (10.1186/s13317-019-0116-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Joris Godelaine
- 1Department of Neurosciences, Laboratory for Molecular Neurobiomarker Research, KU Leuven (University of Leuven), Herestraat 49, 3000 Leuven, Belgium.,2Laboratory Medicine, University Hospitals Leuven, UZ Herestraat 49, Leuven, Belgium
| | - Xavier Bossuyt
- 2Laboratory Medicine, University Hospitals Leuven, UZ Herestraat 49, Leuven, Belgium.,3Department of Microbiology and Immunology, Clinical and Diagnostic Immunology, KU Leuven (University of Leuven) Leuven, Herestraat 49, Leuven, Belgium
| | - Koen Poesen
- 1Department of Neurosciences, Laboratory for Molecular Neurobiomarker Research, KU Leuven (University of Leuven), Herestraat 49, 3000 Leuven, Belgium.,2Laboratory Medicine, University Hospitals Leuven, UZ Herestraat 49, Leuven, Belgium
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Abstract
Mono-ADP-ribosyltransferases of the PARP/ARTD enzyme family are enzymes catalyzing the transfer of a single ADP-ribose unit to target proteins. The enzymes have various roles in vital cellular processes such as DNA repair and transcription, and many of the enzymes are linked to cancer-relevant functions. Thus inhibition of the enzymes is a potential way to discover and develop new drugs against cancer. Here we describe an activity-based screening assay for mono-ADP-ribosyltransferases. The assay utilizes the natural substrate of the enzymes, NAD+, and it is based on chemically converting the leftover substrate to a fluorophore and measuring its relative concentration after the enzymatic reaction. The assay is homogenous, robust, and cost-effective and, most importantly, applicable to mono-ADP-ribosyltransferases as well as poly-ADP-ribosyltransferases for screening of small-molecule inhibitors against the enzymes.
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Affiliation(s)
- Teemu Haikarainen
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Sudarshan Murthy
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Mirko M Maksimainen
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Lari Lehtiö
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland.
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Roush KS, Jeffries MKS. Gonadosomatic index as a confounding variable in fish-based screening assays for the detection of anti-estrogens and nonaromatizable androgens. Environ Toxicol Chem 2019; 38:603-615. [PMID: 30614037 DOI: 10.1002/etc.4353] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Revised: 09/19/2018] [Accepted: 12/27/2018] [Indexed: 06/09/2023]
Abstract
The presence of reproductive endocrine-disrupting compounds (REDCs) in the environment poses a potential threat to fish and wildlife, because exposures are capable of altering sexual development, reproductive success, and behavior. Fish-based screening assays are often utilized to screen for the presence of REDCs in surface waters and to assess single chemicals for potential endocrine-disrupting activity. In an effort to improve such screening assays, the goal of the present study was to determine whether the gonadosomatic index (GSI) of female fathead minnows (Pimephales promelas), as assessed via external characteristics, influences their response to REDC exposure. Specifically, we sought to determine whether low-GSI females differed from high-GSI females in their responses to the model anti-estrogen fadrozole and the model androgen 17β-trenbolone, and whether there was a preferable classification in the context of REDC screening. Low-GSI females were more sensitive to fadrozole at the lower concentration of fadrozole (5 µg/L) and to the higher concentration of trenbolone (50 ng/L), whereas high-GSI females were more sensitive at the lower concentration of trenbolone (5 ng/L). The differential response of low- and high-GSI females to REDCs indicates that GSI influences exposure outcome, and should subsequently be taken into consideration in the implementation of screening assays, as failure to utilize fish of the appropriate reproductive status may skew the test results. Environ Toxicol Chem 2019;38:603-615. © 2019 SETAC.
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Affiliation(s)
- Kyle S Roush
- Department of Biology, Texas Christian University, Fort Worth, Texas, USA
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Weingartner AM, Sauer DF, Dhoke GV, Davari MD, Ruff AJ, Schwaneberg U. A hydroquinone-specific screening system for directed P450 evolution. Appl Microbiol Biotechnol 2018; 102:9657-9667. [PMID: 30191291 PMCID: PMC6208966 DOI: 10.1007/s00253-018-9328-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 08/10/2018] [Accepted: 08/14/2018] [Indexed: 11/24/2022]
Abstract
The direct hydroxylation of benzene to hydroquinone (HQ) under mild reaction conditions is a challenging task for chemical catalysts. Cytochrome P450 (CYP) monooxygenases are known to catalyze the oxidation of a variety of aromatic compounds with atmospheric dioxygen. Protein engineering campaigns led to the identification of novel P450 variants, which yielded improvements in respect to activity, specificity, and stability. An effective screening strategy is crucial for the identification of improved enzymes with desired characteristics in large mutant libraries. Here, we report a first screening system designed for screening of P450 variants capable to produce hydroquinones. The hydroquinone quantification assay is based on the interaction of 4-nitrophenylacetonitrile (NpCN) with hydroquinones under alkaline conditions. In the 96-well plate format, a low detection limit (5 μM) and a broad linear detection range (5 to 250 μM) were obtained. The NpCN assay can be used for the quantification of dihydroxylated aromatic compounds such as hydroquinones, catechols, and benzoquinones. We chose the hydroxylation of pseudocumene by P450 BM3 as a target reaction and screened for improved trimethylhydroquinone (TMHQ) formation. The new P450 BM3 variant AW2 (R47Q, Y51F, I401M, A330P) was identified by screening a saturation mutagenesis library of amino acid position A330 with the NpCN assay. In summary, a 70-fold improved TMHQ formation was achieved with P450 BM3 AW2 when compared to the wild type (WT) and a 1.8-fold improved TMHQ formation compared to the recently reported P450 BM3 M3 (R47S, Y51W, A330F, I401M).
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Affiliation(s)
| | - Daniel F Sauer
- Institute of Biotechnology, RWTH Aachen University, Worringerweg 3, 52074, Aachen, Germany
| | - Gaurao V Dhoke
- Institute of Biotechnology, RWTH Aachen University, Worringerweg 3, 52074, Aachen, Germany
| | - Mehdi D Davari
- Institute of Biotechnology, RWTH Aachen University, Worringerweg 3, 52074, Aachen, Germany
| | - Anna Joëlle Ruff
- Institute of Biotechnology, RWTH Aachen University, Worringerweg 3, 52074, Aachen, Germany.
| | - Ulrich Schwaneberg
- Institute of Biotechnology, RWTH Aachen University, Worringerweg 3, 52074, Aachen, Germany.
- DWI - Leibniz Institut für Interaktive Materialien, Forckenbeckstraße 50, 52074, Aachen, Germany.
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Arini A, Mittal K, Dornbos P, Head J, Rutkiewicz J, Basu N. A cell-free testing platform to screen chemicals of potential neurotoxic concern across twenty vertebrate species. Environ Toxicol Chem 2017; 36:3081-3090. [PMID: 28594109 DOI: 10.1002/etc.3880] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 03/09/2017] [Accepted: 06/05/2017] [Indexed: 05/20/2023]
Abstract
There is global demand for new in vitro testing tools for ecological risk assessment. The objective of the present study was to apply a set of cell-free neurochemical assays to screen many chemicals across many species in a relatively high-throughput manner. The platform assessed 7 receptors and enzymes that mediate neurotransmission of γ-aminobutyric acid, dopamine, glutamate, and acetylcholine. Each assay was optimized to work across 20 vertebrate species (5 fish, 5 birds, 7 mammalian wildlife, 3 biomedical species including humans). We tested the screening assay platform against 80 chemicals (23 pharmaceuticals and personal care products, 20 metal[loid]s, 22 polycyclic aromatic hydrocarbons and halogenated organic compounds, 15 pesticides). In total, 10 800 species-chemical-assay combinations were tested, and significant differences were found in 4041 cases. All 7 assays were significantly affected by at least one chemical in each species tested. Among the 80 chemicals tested, nearly all resulted in a significant impact on at least one species and one assay. The 5 most active chemicals were prochloraz, HgCl2 , Sn, benzo[a]pyrene, and vinclozolin. Clustering analyses revealed groupings according to chemicals, species, and chemical-assay combinations. The results show that cell-free assays can screen a large number of samples in a short period of time in a cost-effective manner in a range of animals not easily studied using traditional approaches. Strengths and limitations of this approach are discussed, as well as next steps. Environ Toxicol Chem 2017;36:3081-3090. © 2017 SETAC.
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Affiliation(s)
- Adeline Arini
- Department of Environmental Health Sciences, University of Michigan, Ann Arbor, Michigan, USA
- Faculty of Agricultural and Environmental Sciences, McGill University, Montreal, Quebec, Canada
| | - Krittika Mittal
- Department of Environmental Health Sciences, University of Michigan, Ann Arbor, Michigan, USA
- Faculty of Agricultural and Environmental Sciences, McGill University, Montreal, Quebec, Canada
| | - Peter Dornbos
- Department of Environmental Health Sciences, University of Michigan, Ann Arbor, Michigan, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
- Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan, USA
| | - Jessica Head
- Department of Environmental Health Sciences, University of Michigan, Ann Arbor, Michigan, USA
| | - Jennifer Rutkiewicz
- Department of Environmental Health Sciences, University of Michigan, Ann Arbor, Michigan, USA
- ToxServices, Ann Arbor, Michigan, USA
| | - Niladri Basu
- Department of Environmental Health Sciences, University of Michigan, Ann Arbor, Michigan, USA
- Faculty of Agricultural and Environmental Sciences, McGill University, Montreal, Quebec, Canada
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12
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Heuson E, Petit JL, Charmantray F, de Bérardinis V, Gefflaut T. Continuous High-Throughput Colorimetric Assays for α-Transaminases. Methods Mol Biol 2018; 1685:233-45. [PMID: 29086312 DOI: 10.1007/978-1-4939-7366-8_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Transaminases are efficient tools for the stereoselective conversion of prochiral ketones into valuable chiral amines. Notably, the diversity of naturally occurring α-transaminases offers access to a wide range of L- and D-α-amino acids. We describe here two continuous colorimetric assays for the quantification of transamination activities between a keto acid and a standard donor substrate (L- or D-Glutamic acid or cysteine sulfinic acid). These assays are helpful for kinetic studies as well as for high-throughput screening of enzyme collections.
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13
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Otero-Guerra L, Fernández-Blázquez A, Vazquez F. Rapid diagnosis of sexually transmitted infections. Enferm Infecc Microbiol Clin 2017; 35:444-450. [PMID: 28238505 DOI: 10.1016/j.eimc.2017.01.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 01/05/2017] [Indexed: 10/20/2022]
Abstract
Sexually transmitted infections (STIs) are responsible for an enormous burden of morbidity and mortality. Worldwide, millions of cases of STIs, such as syphilis, chlamydia, or gonorrhoea occur every year, and there is now an increase in antimicrobial resistance in pathogens, such as gonococcus. Delay in diagnosis is one of the factors that justifies the difficulty in controlling these infections. Rapid diagnostic tests allow the introduction of aetiological treatment at the first visit, and also leads to treating symptomatic and asymptomatic patients more effectively, as well as to interrupt the epidemiological transmission chain without delay. The World Health Organisation includes these tests in its global strategy against STIs.
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Affiliation(s)
| | | | - Fernando Vazquez
- Servicio de Microbiología, Hospital Universitario Central de Asturias, Oviedo, España; Departamento de Biología Funcional, Área de Microbiología, Facultad de Medicina, Oviedo, España; Fundación de Investigación Oftalmológica, Instituto Oftalmológico Fernández-Vega, Oviedo, España.
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14
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Chan LLY, Smith T, Kumph KA, Kuksin D, Kessel S, Déry O, Cribbes S, Lai N, Qiu J. A high-throughput AO/PI-based cell concentration and viability detection method using the Celigo image cytometry. Cytotechnology 2016; 68:2015-25. [PMID: 27488883 DOI: 10.1007/s10616-016-0015-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 07/25/2016] [Indexed: 01/26/2023] Open
Abstract
To ensure cell-based assays are performed properly, both cell concentration and viability have to be determined so that the data can be normalized to generate meaningful and comparable results. Cell-based assays performed in immuno-oncology, toxicology, or bioprocessing research often require measuring of multiple samples and conditions, thus the current automated cell counter that uses single disposable counting slides is not practical for high-throughput screening assays. In the recent years, a plate-based image cytometry system has been developed for high-throughput biomolecular screening assays. In this work, we demonstrate a high-throughput AO/PI-based cell concentration and viability method using the Celigo image cytometer. First, we validate the method by comparing directly to Cellometer automated cell counter. Next, cell concentration dynamic range, viability dynamic range, and consistency are determined. The high-throughput AO/PI method described here allows for 96-well to 384-well plate samples to be analyzed in less than 7 min, which greatly reduces the time required for the single sample-based automated cell counter. In addition, this method can improve the efficiency for high-throughput screening assays, where multiple cell counts and viability measurements are needed prior to performing assays such as flow cytometry, ELISA, or simply plating cells for cell culture.
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Affiliation(s)
- Leo Li-Ying Chan
- Department of Technology R&D, Nexcelom Bioscience LLC, 360 Merrimack St. Building 9, Lawrence, MA, 01843, USA.
| | - Tim Smith
- Department of Technology R&D, Nexcelom Bioscience LLC, 360 Merrimack St. Building 9, Lawrence, MA, 01843, USA
| | - Kendra A Kumph
- Department of Technology R&D, Nexcelom Bioscience LLC, 360 Merrimack St. Building 9, Lawrence, MA, 01843, USA
| | - Dmitry Kuksin
- Department of Technology R&D, Nexcelom Bioscience LLC, 360 Merrimack St. Building 9, Lawrence, MA, 01843, USA
| | - Sarah Kessel
- Department of Technology R&D, Nexcelom Bioscience LLC, 360 Merrimack St. Building 9, Lawrence, MA, 01843, USA
| | - Olivier Déry
- Department of Technology R&D, Nexcelom Bioscience LLC, 360 Merrimack St. Building 9, Lawrence, MA, 01843, USA
| | - Scott Cribbes
- Department of Technology R&D, Nexcelom Bioscience LLC, 360 Merrimack St. Building 9, Lawrence, MA, 01843, USA
| | - Ning Lai
- Department of Technology R&D, Nexcelom Bioscience LLC, 360 Merrimack St. Building 9, Lawrence, MA, 01843, USA
| | - Jean Qiu
- Department of Technology R&D, Nexcelom Bioscience LLC, 360 Merrimack St. Building 9, Lawrence, MA, 01843, USA
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Abstract
The bioluminescent resonance energy transfer (BRET) assay has been extensively used in cell-based and in vivo imaging systems for detecting protein-protein interactions in the native environment of living cells. These protein-protein interactions are essential for the functional response of many signaling pathways to environmental chemicals. BRET has been used as a toxicological tool for identifying chemicals that either induce or inhibit these protein-protein interactions. This chapter focuses on describing the toxicological applications of BRET and its optimization as a high-throughput detection system in live cells. Here we review the construction of BRET fusion proteins, describe the BRET methodology, and outline strategies to overcome obstacles that may arise. Furthermore, we describe the advantage of BRET over other resonance energy transfer methods for monitoring protein-protein interactions.
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Affiliation(s)
- Carlos Coriano
- Department of Oncology, University of Wisconsin-Madison, 7459 WIMR II, 1111 Highland Avenue, Madison, WI, 53705-2275, USA
| | - Emily Powell
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Wei Xu
- Department of Oncology, University of Wisconsin-Madison, 7459 WIMR II, 1111 Highland Avenue, Madison, WI, 53705-2275, USA.
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16
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Zhang Y, Li Y, Qin Z, Wang H, Li J. A screening assay for thyroid hormone signaling disruption based on thyroid hormone-response gene expression analysis in the frog Pelophylax nigromaculatus. J Environ Sci (China) 2015; 34:143-154. [PMID: 26257357 DOI: 10.1016/j.jes.2015.01.028] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2014] [Revised: 12/30/2014] [Accepted: 01/16/2015] [Indexed: 06/04/2023]
Abstract
Amphibian metamorphosis provides a wonderful model to study the thyroid hormone (TH) signaling disrupting activity of environmental chemicals, with Xenopus laevis as the most commonly used species. This study aimed to establish a rapid and sensitive screening assay based on TH-response gene expression analysis using Pelophylax nigromaculatus, a native frog species distributed widely in East Asia, especially in China. To achieve this, five candidate TH-response genes that were sensitive to T3 induction were chosen as molecular markers, and T3 induction was determined as 0.2 nmol/L T3 exposure for 48 hr. The developed assay can detect the agonistic activity of T3 with a lowest observed effective concentration of 0.001 nmol/L and EC50 at around 0.118-1.229 nmol/L, exhibiting comparable or higher sensitivity than previously reported assays. We further validated the efficiency of the developed assay by detecting the TH signaling disrupting activity of tetrabromobisphenol A (TBBPA), a known TH signaling disruptor. In accordance with previous reports, we found a weak TH agonistic activity for TBBPA in the absence of T3, whereas a TH antagonistic activity was found for TBBPA at higher concentrations in the presence of T3, showing that the P. nigromaculatus assay is effective for detecting TH signaling disrupting activity. Importantly, we observed non-monotonic dose-dependent disrupting activity of TBBPA in the presence of T3, which is difficult to detect with in vitro reporter gene assays. Overall, the developed P. nigromaculatus assay can be used to screen TH signaling disrupting activity of environmental chemicals with high sensitivity.
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Affiliation(s)
- Yinfeng Zhang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.; Department of Environmental Bio-Technology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Yuanyuan Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Zhanfen Qin
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China..
| | - Huili Wang
- Department of Environmental Bio-Technology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Jianzhong Li
- Department of Environmental Bio-Technology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
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17
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Vidal N, Cavaille J, Graziani F, Robin M, Ouari O, Pietri S, Stocker P. High throughput assay for evaluation of reactive carbonyl scavenging capacity. Redox Biol 2014; 2:590-8. [PMID: 24688895 PMCID: PMC3969608 DOI: 10.1016/j.redox.2014.01.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 01/16/2014] [Accepted: 01/20/2014] [Indexed: 11/19/2022] Open
Abstract
Many carbonyl species from either lipid peroxidation or glycoxidation are extremely reactive and can disrupt the function of proteins and enzymes. 4-hydroxynonenal and methylglyoxal are the most abundant and toxic lipid-derived reactive carbonyl species. The presence of these toxics leads to carbonyl stress and cause a significant amount of macromolecular damages in several diseases. Much evidence indicates trapping of reactive carbonyl intermediates may be a useful strategy for inhibiting or decreasing carbonyl stress-associated pathologies. There is no rapid and convenient analytical method available for the assessment of direct carbonyl scavenging capacity, and a very limited number of carbonyl scavengers have been identified to date, their therapeutic potential being highlighted only recently. In this context, we have developed a new and rapid sensitive fluorimetric method for the assessment of reactive carbonyl scavengers without involvement glycoxidation systems. Efficacy of various thiol- and non-thiol-carbonyl scavenger pharmacophores was tested both using this screening assay adapted to 96-well microplates and in cultured cells. The scavenging effects on the formation of Advanced Glycation End-product of Bovine Serum Albumin formed with methylglyoxal, 4-hydroxynonenal and glucose-glycated as molecular models were also examined. Low molecular mass thiols with an α-amino-β-mercaptoethane structure showed the highest degree of inhibitory activity toward both α,β-unsaturated aldehydes and dicarbonyls. Cysteine and cysteamine have the best scavenging ability toward methylglyoxal. WR-1065 which is currently approved for clinical use as a protective agent against radiation and renal toxicity was identified as the best inhibitor of 4-hydroxynonenal. We describe a rapid method for assessment of reactive carbonyl scavengers. We evaluated the carbonyl scavenger activity of various pharmacophores. α-amino-β-mercaptoethane structure showed the highest degree of activity.
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Affiliation(s)
- N. Vidal
- Aix Marseille Université, CNRS, ICR UMR 7273, 13397, Marseille, France
| | - J.P. Cavaille
- Aix Marseille Université, CNRS, ICR UMR 7273, 13397, Marseille, France
| | - F. Graziani
- Aix Marseille Université, CNRS, ISM2 UMR 7313, 13397, Marseille, France
| | - M. Robin
- Aix Marseille Université, CNRS, ICR UMR 7273, 13397, Marseille, France
| | - O. Ouari
- Aix Marseille Université, CNRS, ICR UMR 7273, 13397, Marseille, France
| | - S. Pietri
- Aix Marseille Université, CNRS, ICR UMR 7273, 13397, Marseille, France
| | - P. Stocker
- Aix Marseille Université, CNRS, ICR UMR 7273, 13397, Marseille, France
- Corresponding author. Tel.: +33 4 91 28 87 92; fax: +33 4 91 28 87 58.
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18
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Walsh KB, DeRoller N, Zhu Y, Koley G. Application of ion-sensitive field effect transistors for ion channel screening. Biosens Bioelectron 2013; 54:448-54. [PMID: 24315877 DOI: 10.1016/j.bios.2013.11.038] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 11/04/2013] [Accepted: 11/11/2013] [Indexed: 11/25/2022]
Abstract
Cell-based screening assays are now widely used for identifying compounds that serve as ion channel modulators. However, instrumentation for the automated, real-time analysis of ion flux from clonal and primary cells is lacking. This study describes the initial development of an ion-sensitive field effect transistor (ISFET)-based screening assay for the acquisition of K(+) efflux data from cells cultured in multi-well plates. Silicon-based K(+)-sensitive ISFETs were tested for their electrical response to varying concentrations of KCl and were found to display a linear response relationship to KCl in the range of 10 µM-1 mM. The ISFETs, along with reference electrodes, were inserted into fast-flow chambers containing either human colonic T84 epithelial cells or U251-MG glioma cells. Application of the Ca(2+) ionophore A23187 (1 µM), to activate Ca(2+)-activated non-selective cation (NSC) channels (T84 cells) and large conductance Ca(2+)-activated K(+) (BK) channels (U251 cells), resulted in time-dependent increases in the extracellular K(+) concentration ([K(+)]o) as measured with the ISFETs. Treatment of the cells with blockers of either the NSC or BK channels, caused a strong inhibition of the A23187-induced increase in [K(+)]o. These results were consistent with ion current measurements obtained using the whole-cell arrangement of the patch clamp procedure. In addition, K(+) efflux data could be acquired in parallel from multiple cell chambers using the ISFET sensors. Given the non-invasive properties of the probes, the ISFET-based assay should be adaptable for screening ion channels in various cell types.
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Affiliation(s)
- Kenneth B Walsh
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina, School of Medicine, Columbia, SC 29209, USA.
| | - Nicholas DeRoller
- Department of Electrical Engineering, University of South Carolina, School of Engineering, Columbia, SC 29208, USA
| | - Yihao Zhu
- Department of Electrical Engineering, University of South Carolina, School of Engineering, Columbia, SC 29208, USA
| | - Goutam Koley
- Department of Electrical Engineering, University of South Carolina, School of Engineering, Columbia, SC 29208, USA
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Wheeler JR, Panter GH, Weltje L, Thorpe KL. Test concentration setting for fish in vivo endocrine screening assays. Chemosphere 2013; 92:1067-1076. [PMID: 23481302 DOI: 10.1016/j.chemosphere.2013.01.102] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Revised: 12/21/2012] [Accepted: 01/24/2013] [Indexed: 06/01/2023]
Abstract
Fish in vivo screening methods to detect endocrine active substances, specifically interacting with the hypothalamic-pituitary-gonadal axis, have been developed by both the Organization for Economic Co-operation and Development (OECD) and United States Environmental Protection Agency (US-EPA). In application of these methods, i.e. regulatory testing, this paper provides a proposal on the setting of test concentrations using all available acute and chronic data and also discusses the importance of avoiding the confounding effects of systemic toxicity on endocrine endpoints. This guidance is aimed at reducing the number of false positives and subsequently the number of inappropriate definitive vertebrate studies potentially triggered by effects consequent to systemic, rather than endocrine, toxicity. At the same time it provides a pragmatic approach that maximizes the probability of detecting an effect, if it exists, thus limiting the potential for false negative outcomes.
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Affiliation(s)
- James R Wheeler
- Syngenta Environmental Safety, Jealott's Hill International Research Centre, Bracknell, Berkshire RG42 6EY, United Kingdom.
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Lau WH, Leong WS, Ismail Z, Gam LH. Qualification and application of an ELISA for the determination of Tamm Horsfall protein (THP) in human urine and its use for screening of kidney stone disease. Int J Biol Sci 2008; 4:215-22. [PMID: 18695745 PMCID: PMC2500153 DOI: 10.7150/ijbs.4.215] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2008] [Accepted: 08/02/2008] [Indexed: 11/05/2022] Open
Abstract
Kidney stone disease affects 1 - 20% of the general population. At present, the diagnosis of a stone is done using radiography method when noticeable symptoms appeared. We developed a non-invasive quantitative assay for urinary THP, namely ELISA; whereby our previous study and other reports had shown the usefulness of THP as biomarker for kidney stone disease. Since urine is biological fluid that is easily obtainable, this method could be used as a screening assay for kidney stone prior to confirmation with radiography. The ELISA gave assay linearity r(2) > 0.999 within the range of 109 ng/mL to 945 ng/mL THP. Assay precisions were < 4% (C.V.) for repeatability and < 5% (C.V.) for reproducibility. Assay accuracy range from 97.7% to 101.2% at the various THP concentrations tested. Assay specificity and sensitivity were 80% and 86%, respectively. The cut-off points at P < 0.05 were 37.0 and 41.2 mug/mL for male and female, respectively. The assay is cost effective and rapid whereby the cost for assaying each urine sample in duplicate is approximately USD0.35 and within 5 hours, 37 samples can be assayed alongside full range of standards and 3 QC samples in each plate. Furthermore, sample preparation is relatively easy where urine sample was diluted 10 times in TEA buffer. The usability of the ELISA method for diagnosis of kidney stone disease is evaluated with 117 healthy subjects and 58 stone formers.
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Affiliation(s)
- Wai-Hoe Lau
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, USM, Penang, Malaysia
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