scholarly journals High Throughput miRNA Screening Identifies miR-574-3p Hyperproductive Effect in CHO Cells

Biomolecules ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1125
Author(s):  
Živa Švab ◽  
Luca Braga ◽  
Corrado Guarnaccia ◽  
Ivan Labik ◽  
Jeremias Herzog ◽  
...  
Keyword(s):  
High Throughput ◽  
Cho Cells ◽  
High Throughput Screening ◽  
Single Gene ◽  
Chinese Hamster ◽  
Cost Effective ◽  
Good Alternative ◽  
Human Mirnas ◽  
Cell Productivity ◽  
Life Saving

CHO is the cell line of choice for the manufacturing of many complex biotherapeutics. The constant upgrading of cell productivity is needed to meet the growing demand for these life-saving drugs. Manipulation of small non-coding RNAs—miRNAs—is a good alternative to a single gene knockdown approach due to their post-transcriptional regulation of entire cellular pathways without posing translational burden to the production cell. In this study, we performed a high-throughput screening of 2042-human miRNAs and identified several candidates able to increase cell-specific and overall production of Erythropoietin and Etanercept in CHO cells. Some of these human miRNAs have not been found in Chinese hamster cells and yet were still effective in them. We identified miR-574-3p as being able, when overexpressed in CHO cells, to improve overall productivity of Erythropoietin and Etanercept titers from 1.3 to up to 2-fold. In addition, we validated several targets of miR-574-3p and identified p300 as a main target of miR-574-3p in CHO cells. Furthermore, we demonstrated that stable CHO cell overexpressing miRNAs from endogenous CHO pri-miRNA sequences outperform the cells with human pri-miRNA sequences. Our findings highlight the importance of flanking genomic sequences, and their secondary structure features, on pri-miRNA processing offering a novel, cost-effective and fast strategy as a valuable tool for efficient miRNAs engineering in CHO cells.

scholarly journals Identification and Characterization of a Small-Molecule Rabies Virus Entry Inhibitor

2020 ◽  
Vol 94 (13) ◽  
Author(s):  
Venice Du Pont ◽  
Christoph Wirblich ◽  
Jeong-Joong Yoon ◽  
Robert M. Cox ◽  
Matthias J. Schnell ◽  
...  
Keyword(s):  
G Protein ◽  
Small Molecule ◽  
High Throughput ◽  
Viral Entry ◽  
Cost Effective ◽  
Molecular Probe ◽  
Entry Inhibitor ◽  
Protein Fusion ◽  
Life Saving

ABSTRACT Rabies virus (RABV) causes a severe and fatal neurological disease, but morbidity is vaccine preventable and treatable prior to the onset of clinical symptoms. However, immunoglobulin (IgG)-based rabies postexposure prophylaxis (PEP) is expensive, restricting access to life-saving treatment, especially for patients in low-income countries where the clinical need is greatest, and does not confer cross-protection against newly emerging phylogroup II lyssaviruses. Toward identifying a cost-effective replacement for the IgG component of rabies PEP, we developed and implemented a high-throughput screening protocol utilizing a single-cycle RABV reporter strain. A large-scale screen and subsequent direct and orthogonal counterscreens identified a first-in-class direct-acting RABV inhibitor, GRP-60367, with a specificity index (SI) of >100,000. Mechanistic characterization through time-of-addition studies, transient cell-to-cell fusion assays, and chimeric vesicular stomatitis virus (VSV) recombinants expressing the RABV glycoprotein (G) demonstrated that GRP-60367 inhibits entry of a subset of RABV strains. Resistance profiling of the chemotype revealed hot spots in conserved hydrophobic positions of the RABV G protein fusion loop that were confirmed in transient cell-to-cell fusion assays. Transfer of RABV G genes with signature resistance mutations into a recombinant VSV backbone resulted in the recovery of replication-competent virions with low susceptibility to the inhibitor. This work outlines a tangible strategy for mechanistic characterization and resistance profiling of RABV drug candidates and identified a novel, well-behaved molecular probe chemotype that specifically targets the RABV G protein and prevents G-mediated viral entry. IMPORTANCE Rabies PEP depends on anti-RABV IgG, which is expensive and in limited supply in geographical areas with the highest disease burden. Replacing the IgG component with a cost-effective and shelf-stable small-molecule antiviral could address this unmet clinical need by expanding access to life-saving medication. This study has established a robust protocol for high-throughput anti-RABV drug screens and identified a chemically well-behaved, first-in-class hit with nanomolar anti-RABV potency that blocks RABV G protein-mediated viral entry. Resistance mapping revealed a druggable site formed by the G protein fusion loops that has not previously emerged as a target for neutralizing antibodies. Discovery of this RABV entry inhibitor establishes a new molecular probe to advance further mechanistic and structural characterization of RABV G that may aid in the design of a next-generation clinical candidate against RABV.

Development of a β-Lactamase Reporter Gene Assay for Metabotropic Glutamate Receptor 1 by Using Coexpression of Glutamate Transporter

2010 ◽  
Vol 15 (2) ◽  
pp. 148-158 ◽  
Author(s):  
Gentaroh Suzuki ◽  
Hiroshi Kawamoto ◽  
Hisashi Ohta
Keyword(s):  
High Throughput ◽  
High Throughput Screening ◽  
Metabotropic Glutamate Receptor ◽  
Chinese Hamster ◽  
High Sensitivity ◽  
Reporter Assay ◽  
Activated T Cells ◽  
Basal Activity ◽  
Gene Assay ◽  
Very High

mGluR1 antagonists have been postulated to be novel CNS drugs, including antipsychotics. Toward this end, the authors developed a β-lactamase reporter assay to identify mGluR1 antagonists. β-Lactamase has several interesting features for high-throughput screening, including very high sensitivity and less well-to-well variation than other reporter enzymes. mGluR1-expressing Chinese hamster ovary (CHO) cells with the β-lactamase gene under control of the nuclear factor of activated T cells (NFAT) promoter (CHO-NFAT-bla-hmGluR1b) exhibited very high basal activity, resulting in an inadequate signal-to-basal (S/B) ratio. Coexpression of glutamate/aspartate transporter (GLAST) with mGluR1 in the cell line (CHO-NFAT-bla-hmGluR1b-GLAST) dramatically decreased basal activity and improved the S/B ratio (from 2- to 20-fold). The contribution of GLAST to lowering basal activity and increasing the S/B ratio was validated by the expression level of GLAST mRNA and by a GLAST inhibitor. Antagonistic activities of known mGluR1 antagonists in the β-lactamase reporter assay were comparable with those in the conventional Ca2+ mobilization assay. The Z′ factor of the β-lactamase reporter assay was 0.89 under optimized conditions. Taken together, the β-lactamase reporter assay with CHO-NFAT-bla-hmGluR1b-GLAST could be a novel high-throughput assay for mGluR1 antagonist screening. This is the first description of a successful β-lactamase reporter assay among all mGluR subtypes.

scholarly journals Long-Term Storage of Compound Solutions for High-Throughput Screening by Using a Novel 1536-Well Microplate

2009 ◽  
Vol 14 (5) ◽  
pp. 492-498 ◽  
Author(s):  
Martin Joseph Pfeifer ◽  
Guenther Scheel
Keyword(s):  
High Throughput ◽  
High Throughput Screening ◽  
Cost Effective ◽  
The Novel ◽  
Long Term Storage ◽  
Plate Design ◽  
Minor Losses ◽  
Storage Times ◽  
Term Storage

This report describes the features and the performance of a new and significantly improved 1536-well microplate design. The design allows for simple, automation-friendly, and cost-effective storage of compound solutions for high-throughput screening. The plate design is based on Society for Biomolecular Sciences standards for microplates and can be molded from polystyrene or cycloolefin copolymer, thus making the plate suitable for use with acoustic dispensing as well as other conventional liquid dispensing in the nanoliter range. For a 9:1 DMSO/water mix as solvent, the novel plate design has shown to perform over 4 months with only minor losses in solvent. Thus, this novel plate design creates the basis for further reductions in compound storage volumes and allows for an increase in the storage times for microliter volumes for up to a year or more. The high protection against solvent evaporation is also visible for aqueous solutions, thus allowing for reduced edge effects during screening campaigns.

scholarly journals A Cell-Based Ultra-High-Throughput Screening Assay for Identifying Inhibitors of D-Amino Acid Oxidase

2006 ◽  
Vol 11 (5) ◽  
pp. 481-487 ◽  
Author(s):  
Philip E. Brandish ◽  
Chi-Sung Chiu ◽  
Jonathan Schneeweis ◽  
Nicholas J. Brandon ◽  
Clare L. Leech ◽  
...  
Keyword(s):  
Amino Acid ◽  
High Throughput ◽  
High Throughput Screening ◽  
Hormone Receptors ◽  
Chinese Hamster ◽  
Acid Oxidase ◽  
Amino Acid Oxidase ◽  
Compound Libraries ◽  
High Throughput Screening Assay ◽  
Artificial Environment

Enzymes are often considered less “druggable” targets than ligand-regulated proteins such as G-protein-coupled receptors, ion channels, or other hormone receptors. Reasons for this include cellular location (intracellular vs. cell surface), typically lower affinities for the binding of small molecules compared to ligand-specific receptors, and binding (catalytic) sites that are often charged or highly polar. A practical drawback to the discovery of compounds targeting enzymes is that screening of compound libraries is typically carried out in cell-free activity assays using purified protein in an inherently artificial environment. Cell-based assays, although often arduous to design for enzyme targets, are the preferred discovery tool for the screening of large compound libraries. The authors have recently described a novel cell-based approach to screening for inhibitors of a phosphatase enzyme and now report on the development and implementation of a homogeneous 3456-well plate assay for D-amino acid oxidase (DAO). Human DAO was stably expressed in Chinese hamster ovary (CHO) cells, and its activity was measured as the amount of hydrogen peroxide detected in the growth medium following feeding the cells with D-serine. In less than 12 weeks, the authors proved the concept in 96-and then 384-well formats, miniaturized the assay to the 3456-well (nanoplate) scale, and screened a library containing more than 1 million compounds. They have identified several cell-permeable inhibitors of DAO from this cell-based high-throughput screening, which provided the discovery program with a few novel and attractive lead structures.

scholarly journals Discovery of Acid-Stable Oxygen Evolution Catalysts : High-throughput Computational Screening of Equimolar Bimetallic Oxides

2020 ◽  
Author(s):  
Seoin Back ◽  
Kevin Tran ◽  
Zachary Ulissi
Keyword(s):  
Oxygen Evolution ◽  
High Throughput ◽  
High Throughput Screening ◽  
Noble Metals ◽  
Cost Effective ◽  
Oxide Catalysts ◽  
Computational Screening ◽  
Energy Conversion Systems ◽  
Acid Stable ◽  
Bimetallic Oxides

Discovering acid-stable, cost-effective and active catalysts for oxygen evolution reaction (OER) is critical since this reaction is bottlenecking many electrochemical energy conversion systems. Current systems use extremely expensive iridium oxide catalysts. Identifying Ir-free or catalysts with reduced Ir-composition has been suggested as goals, but no systematic strategy to discover such catalysts has been reported. In this work, we performed high-throughput computational screening to investigate bimetalic oxide catalysts with space groups derived from those of IrO$_x$, identified promising OER catalysts predicted to satisfy all the desired properties: Co-Ir, Fe-Ir and Mo-Ir bimetallic oxides. We find that for the given crystal structures explored, it is essential to include noble metals to maintain the acid-stability, although one-to-one mixing of noble and non-noble metal oxides could keep the materials survive under the acidic conditions. Based on the calculated results, we provide insights to efficiently perform future high-throughput screening to discover catalysts with desirable properties.

scholarly journals Sorting out antibiotics' mechanisms of action: a double fluorescent protein reporter for high throughput screening of ribosome and DNA biosynthesis inhibitors

2016 ◽  
pp. AAC.02117-16 ◽  
Author(s):  
Ilya A. Osterman ◽  
Ekaterina S. Komarova ◽  
Dmitry I. Shiryaev ◽  
Ilya A. Korniltsev ◽  
Irina M. Khven ◽  
...  
Keyword(s):  
High Throughput ◽  
High Throughput Screening ◽  
Protein Gene ◽  
Fluorescent Protein ◽  
Fluorescent Proteins ◽  
Cost Effective ◽  
High Signal ◽  
Red Fluorescent Protein ◽  
Reporter System ◽  
Ribosome Stalling

In order to accelerate drug discovery, a simple, reliable and cost-effective system for high-throughput identification of a potential antibiotic mechanism of action is required. To facilitate such screening of new antibiotics, we created a double reporter system for not only antimicrobial activity detection, but also for simultaneous sorting of potential antimicrobials into those that cause ribosome stalling, and others that induce SOS response due to DNA damage. In this reporter system the red fluorescent protein generfpwas placed under the control of the SOS-induciblesulApromoter. The far-red fluorescent protein genekatushka2Swas inserted downstream the tryptophan attenuator where two tryptophan codons were replaced by alanine codons, with simultaneous replacement of the complementary part of the attenuator, to preserve the ability to form secondary structures that influence transcription termination. This genetically modified attenuator makes possible Katushka2S expression only upon exposure to any ribosome stalling compounds. The application of red and far-red fluorescent proteins provides a high signal-to-background ratio without any need in enzymatic substrates for detection of the reporter activity. This reporter was shown to be efficient in high-throughput screening of both synthetic and natural chemicals.

High-throughput screening of drug-binding dynamics to HERG improves early drug safety assessment

2013 ◽  
Vol 304 (1) ◽  
pp. H104-H117 ◽  
Author(s):  
Giovanni Y. Di Veroli ◽  
Mark R. Davies ◽  
Henggui Zhang ◽  
Najah Abi-Gerges ◽  
Mark R. Boyett
Keyword(s):  
High Throughput ◽  
Drug Safety ◽  
High Throughput Screening ◽  
Chinese Hamster Ovary Cells ◽  
Torsade De Pointes ◽  
Chinese Hamster ◽  
Drug Binding ◽  
Binding Kinetics ◽  
Quantitative Prediction ◽  
Delayed Rectifier

The use of computational models to predict drug-induced changes in the action potential (AP) is a promising approach to reduce drug safety attrition but requires a better representation of more complex drug-target interactions to improve the quantitative prediction. The blockade of the human ether-a-go-go-related gene (HERG) channel is a major concern for QT prolongation and Torsade de Pointes risk. We aim to develop quantitative in-silico AP predictions based on a new electrophysiological protocol (suitable for high-throughput HERG screening) and mathematical modeling of ionic currents. Electrophysiological recordings using the IonWorks device were made from HERG channels stably expressed in Chinese hamster ovary cells. A new protocol that delineates inhibition over time was applied to assess dofetilide, cisapride, and almokalant effects. Dynamic effects displayed distinct profiles for these drugs compared with concentration-effects curves. Binding kinetics to specific states were identified using a new HERG Markov model. The model was then modified to represent the canine rapid delayed rectifier K+ current at 37°C and carry out AP predictions. Predictions were compared with a simpler model based on conductance reduction and were found to be much closer to experimental data. Improved sensitivity to concentration and pacing frequency variables was obtained when including binding kinetics. Our new electrophysiological protocol is suitable for high-throughput screening and is able to distinguish drug-binding kinetics. The association of this protocol with our modeling approach indicates that quantitative predictions of AP modulation can be obtained, which is a significant improvement compared with traditional conductance reduction methods.

scholarly journals Optimization of a Luminescence-Based High-Throughput Screening Assay for Detecting Apyrase Activity

2016 ◽  
Vol 22 (1) ◽  
pp. 94-101 ◽  
Author(s):  
John R. Veloria ◽  
Ashwini K. Devkota ◽  
Eun Jeong Cho ◽  
Kevin N. Dalby
Keyword(s):  
High Throughput ◽  
Herbicide Resistance ◽  
High Throughput Screening ◽  
Detection System ◽  
Cost Effective ◽  
Adenosine Monophosphate ◽  
Adenosine Diphosphate ◽  
Screening Assay ◽  
High Throughput Screening Assay ◽  
Automated Screening

Apyrase is a calcium-activated enzyme that catalyzes the conversion of adenosine triphosphate (ATP) to adenosine diphosphate (ADP), adenosine monophosphate (AMP), and Pi. It is currently used in studies involving cancer and platelet aggregation in humans, as well as herbicide resistance in plants. Inhibitors of apyrase are being investigated for their use to suppress tumors and combat herbicide resistance. Only a few inhibitors of apyrase have been reported, many of which were identified through automated screening using a 96-well plate format and colorimetric phosphate detection. However, these screens have had limitations, including large volumes, inconsistent reproducibility, high incidence of false hits, and lack of higher-throughput compatibility. A luciferin/luciferase-based detection system has been reported to examine potential inhibitors of apyrase; however, these reactions were performed in tubes with the assay completion in seconds, which necessitate the development of a high-throughput screening (HTS)–compatible format for screening. Therefore, a more cost-effective biochemical assay that improved the limitations of the previous assay formats using a commercially available luminescence-based detection system was developed. This new robust mix-and-read platform incorporates a low-volume luminescence-based protocol, formatted for use in 384-well microplates. This new format provides a simple and cost-effective method to screen for apyrase inhibitors and will facilitate larger HTS efforts to identify potent inhibitors of apyrase.

scholarly journals Discovery of Acid-Stable Oxygen Evolution Catalysts : High-throughput Computational Screening of Equimolar Bimetallic Oxides

2020 ◽  
Author(s):  
Seoin Back ◽  
Kevin Tran ◽  
Zachary Ulissi
Keyword(s):  
Oxygen Evolution ◽  
High Throughput ◽  
High Throughput Screening ◽  
Noble Metals ◽  
Cost Effective ◽  
Oxide Catalysts ◽  
Computational Screening ◽  
Energy Conversion Systems ◽  
Acid Stable ◽  
Bimetallic Oxides

Discovering acid-stable, cost-effective and active catalysts for oxygen evolution reaction (OER) is critical since this reaction is bottlenecking many electrochemical energy conversion systems. Current systems use extremely expensive iridium oxide catalysts. Identifying Ir-free or catalysts with reduced Ir-composition has been suggested as goals, but no systematic strategy to discover such catalysts has been reported. In this work, we performed high-throughput computational screening to investigate bimetalic oxide catalysts with space groups derived from those of IrO$_x$, identified promising OER catalysts predicted to satisfy all the desired properties: Co-Ir, Fe-Ir and Mo-Ir bimetallic oxides. We find that for the given crystal structures explored, it is essential to include noble metals to maintain the acid-stability, although one-to-one mixing of noble and non-noble metal oxides could keep the materials survive under the acidic conditions. Based on the calculated results, we provide insights to efficiently perform future high-throughput screening to discover catalysts with desirable properties.

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