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McDowell LL, Quinn CL, Leeds JA, Silverman JA, Silver LL. Perspective on Antibacterial Lead Identification Challenges and the Role of Hypothesis-Driven Strategies. SLAS DISCOVERY 2020; 24:440-456. [PMID: 30890054 DOI: 10.1177/2472555218818786] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
For the past three decades, the pharmaceutical industry has undertaken many diverse approaches to discover novel antibiotics, with limited success. We have witnessed and personally experienced many mistakes, hurdles, and dead ends that have derailed projects and discouraged scientists and business leaders. Of the many factors that affect the outcomes of screening campaigns, a lack of understanding of the properties that drive efflux and permeability requirements across species has been a major barrier for advancing hits to leads. Hits that possess bacterial spectrum have seldom also possessed druglike properties required for developability and safety. Persistence in solving these two key barriers is necessary for the reinvestment into discovering antibacterial agents. This perspective narrates our experience in antibacterial discovery-our lessons learned about antibacterial challenges as well as best practices for screening strategies. One of the tenets that guides us is that drug discovery is a hypothesis-driven science. Application of this principle, at all steps in the antibacterial discovery process, should improve decision making and possibly the odds of what has become, in recent decades, an increasingly challenging endeavor with dwindling success rates.
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Affiliation(s)
- Laura L McDowell
- 1 Novartis Institutes for Biomedical Research, Emeryville, CA, USA
| | | | - Jennifer A Leeds
- 1 Novartis Institutes for Biomedical Research, Emeryville, CA, USA
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Esteban Florez FL, Hiers RD, Zhao Y, Merritt J, Rondinone AJ, Khajotia SS. Optimization of a real-time high-throughput assay for assessment of Streptococcus mutans metabolism and screening of antibacterial dental adhesives. Dent Mater 2020; 36:353-365. [PMID: 31952798 PMCID: PMC7042092 DOI: 10.1016/j.dental.2019.12.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 09/17/2019] [Accepted: 12/18/2019] [Indexed: 12/25/2022]
Abstract
Objective. The present work shows the optimization of a high-throughput bioluminescence assay to assess the metabolism of intact Streptococcus mutans biofilms and its utility as a screening method for nanofilled antibacterial dental materials. Methods. The assay was optimized by monitoring changes in bioluminescence mediated by variation of the experimental parameters investigated (growth media and sucrose concentration, inoculum:D-Luciferin ratio, dilution factor, inoculum volume, luminescence wavelength, replicate and luciferase metabolic activity). Confocal microscopy was then used to demonstrate the impact of biofilm growth conditions on the 3-D distribution of extracellular polymeric substance (EPS) within Streptococcus mutans biofilms and its implications as confounding factors in high-throughput studies (HTS). Results. Relative Luminescence Unit (RLU) values from the HTS optimization were analyzed by multivariate ANOVA (α = 0.05) and coefficients of variation, whereas data from 3-D structural parameters and RLU values of biofilms grown on experimental antibacterial dental adhesive resins were analyzed using General Linear Models and Student–Newman–Keuls post hoc tests (α = 0.05). Confocal microscopy demonstrated that biofilm growth conditions significantly influenced the quantity and distribution of EPS within the 3-D structures of the biofilms. An optimized HTS bioluminescence assay was developed and its applicability as a screening method in dentistry was demonstrated using nanofilled experimental antibacterial dental adhesive resins. Significance. The present study is anticipated to positively impact the direction of future biofilm research in dentistry, because it offers fundamental information for the design of metabolic-based assays, increases the current levels of standardization and reproducibility while offering a tool to decrease intra-study variability.
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Affiliation(s)
- Fernando Luis Esteban Florez
- The University of Oklahoma Health Sciences Center, Department of Restorative Sciences, Division of Dental Biomaterials, College of Dentistry, 1201 N. Stonewall Avenue, Oklahoma City, OK, 73117, USA.
| | - Rochelle Denise Hiers
- The University of Oklahoma Health Sciences Center, Department of Restorative Sciences, Division of Dental Biomaterials, College of Dentistry, 1201 N. Stonewall Avenue, Oklahoma City, OK, 73117, USA.
| | - Yan Zhao
- The University of Oklahoma Health Sciences Center, Department of Biostatistics and Epidemiology, College of Public Health, 801 NE 13th Street, Oklahoma City, OK, 73126, USA.
| | - Justin Merritt
- Oregon Health & Science University, Department of Restorative Dentistry, School of Dentistry, MRB424, 3181 SW Sam Jackson Park Rd., Portland, OR, 97239, USA.
| | - Adam Justin Rondinone
- Oak Ridge National Laboratory, Center for Nanophase Materials Sciences, Oak Ridge, TN, 37831, USA.
| | - Sharukh Soli Khajotia
- The University of Oklahoma Health Sciences Center, Department of Restorative Sciences, Division of Dental Biomaterials, College of Dentistry, 1201 N. Stonewall Avenue, Oklahoma City, OK, 73117, USA.
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El Kheir SM, Cherrat L, Awussi AA, Ramia NE, Taha S, Rahman A, Passerini D, Leroi F, Petit J, Mangavel C, Revol-Junelles AM, Borges F. High-Throughput Identification of Candidate Strains for Biopreservation by Using Bioluminescent Listeria monocytogenes. Front Microbiol 2018; 9:1883. [PMID: 30174662 PMCID: PMC6107680 DOI: 10.3389/fmicb.2018.01883] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 07/26/2018] [Indexed: 12/14/2022] Open
Abstract
This article describes a method for high-throughput competition assays using a bioluminescent strain of L. monocytogenes. This method is based on the use of the luminescent indicator strain L. monocytogenes EGDelux. The luminescence of this strain is correlated to growth, which make it suitable to monitor the growth of L. monocytogenes in mixed cultures. To this aim, luminescence kinetics were converted into a single numerical value, called the Luminescence Disturbance Indicator (LDI), which takes into account growth inhibition phenomena resulting in latency increase, decrease in the luminescence rate, or reduction of the maximum luminescence. The LDI allows to automatically and simultaneously handle multiple competition assays which are required for high-throughput screening (HTS) approaches. The method was applied to screen a collection of 1810 strains isolated from raw cow’s milk in order to identify non-acidifying strains with anti-L. monocytogenes bioprotection properties. This method was also successfully used to identify anti-L. monocytogenes candidates within a collection of Lactococcus piscium, a species where antagonism was previously described as non-diffusible and requiring cell-to-cell contact. In conclusion, bioluminescent L. monocytogenes can be used in HTS to identify strains with anti-L. monocytogenes bioprotection properties, irrespectively of the inhibition mechanism.
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Affiliation(s)
- Sara M El Kheir
- Université de Lorraine, LIBio, Nancy, France.,Laboratoire de Biotechnologies Appliquées, EDST, Université Libanaise, Tripoli, Lebanon
| | | | | | - Nancy E Ramia
- Université de Lorraine, LIBio, Nancy, France.,Laboratoire de Biotechnologies Appliquées, EDST, Université Libanaise, Tripoli, Lebanon
| | - Samir Taha
- Laboratoire de Biotechnologies Appliquées, EDST, Université Libanaise, Tripoli, Lebanon
| | - Abdur Rahman
- Department of Industrial Biotechnology, Atta-ur-Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad, Pakistan
| | - Delphine Passerini
- Laboratoire Ecosystèmes Microbiens et Molécules Marines pour les Biotechnologies, Ifremer, Nantes, France
| | - Françoise Leroi
- Laboratoire Ecosystèmes Microbiens et Molécules Marines pour les Biotechnologies, Ifremer, Nantes, France
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Järvinen P, Nybond S, Marcourt L, Ferreira Queiroz E, Wolfender JL, Mettälä A, Karp M, Vuorela H, Vuorela P, Hatakka A, Tammela P. Cell-based bioreporter assay coupled to HPLC micro-fractionation in the evaluation of antimicrobial properties of the basidiomycete fungus Pycnoporus cinnabarinus. PHARMACEUTICAL BIOLOGY 2016; 54:1108-1115. [PMID: 26808592 DOI: 10.3109/13880209.2015.1103754] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
CONTEXT Identification of bioactive components from complex natural product extracts can be a tedious process that aggravates the use of natural products in drug discovery campaigns. OBJECTIVE This study presents a new approach for screening antimicrobial potential of natural product extracts by employing a bioreporter assay amenable to HPLC-based activity profiling. MATERIALS AND METHODS A library of 116 crude extracts was prepared from fungal culture filtrates by liquid-liquid extraction with ethyl acetate, lyophilised, and screened against Escherichia coli using TLC bioautography. Active extracts were studied further with a broth microdilution assay, which was, however, too insensitive for identifying the active microfractions after HPLC separation. Therefore, an assay based on bioluminescent E. coli K-12 (pTetLux1) strain was coupled with HPLC micro-fractionation. RESULTS Preliminary screening yielded six fungal extracts with potential antimicrobial activity. A crude extract from a culture filtrate of the wood-rotting fungus, Pycnoporus cinnabarinus (Jacq.) P. Karst. (Polyporaceae), was selected for evaluating the functionality of the bioreporter assay in HPLC-based activity profiling. In the bioreporter assay, the IC50 value for the crude extract was 0.10 mg/mL. By integrating the bioreporter assay with HPLC micro-fractionation, the antimicrobial activity was linked to LC-UV peak of a compound in the chromatogram of the extract. This compound was isolated and identified as a fungal pigment phlebiarubrone. DISCUSSION AND CONCLUSION HPLC-based activity profiling using the bioreporter-based approach is a valuable tool for identifying antimicrobial compound(s) from complex crude extracts, and offers improved sensitivity and speed compared with traditional antimicrobial assays, such as the turbidimetric measurement.
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Affiliation(s)
- Päivi Järvinen
- a Centre for Drug Research, Division of Pharmaceutical Biosciences, Faculty of Pharmacy , University of Helsinki , Helsinki , Finland
- b Department of Food and Environmental Sciences, Faculty of Agriculture and Forestry , University of Helsinki , Helsinki , Finland
| | - Susanna Nybond
- a Centre for Drug Research, Division of Pharmaceutical Biosciences, Faculty of Pharmacy , University of Helsinki , Helsinki , Finland
| | - Laurence Marcourt
- c School of Pharmaceutical Sciences, EPGL , University of Geneva, University of Lausanne , Geneva , Switzerland
| | - Emerson Ferreira Queiroz
- c School of Pharmaceutical Sciences, EPGL , University of Geneva, University of Lausanne , Geneva , Switzerland
| | - Jean-Luc Wolfender
- c School of Pharmaceutical Sciences, EPGL , University of Geneva, University of Lausanne , Geneva , Switzerland
| | - Aila Mettälä
- b Department of Food and Environmental Sciences, Faculty of Agriculture and Forestry , University of Helsinki , Helsinki , Finland
| | - Matti Karp
- d Department of Chemistry and Bioengineering , Tampere University of Technology , Tampere , Finland
| | - Heikki Vuorela
- e Pharmaceutical Biology, Division of Pharmaceutical Biosciences, Faculty of Pharmacy , University of Helsinki , Helsinki , Finland
| | - Pia Vuorela
- e Pharmaceutical Biology, Division of Pharmaceutical Biosciences, Faculty of Pharmacy , University of Helsinki , Helsinki , Finland
| | - Annele Hatakka
- b Department of Food and Environmental Sciences, Faculty of Agriculture and Forestry , University of Helsinki , Helsinki , Finland
| | - Päivi Tammela
- a Centre for Drug Research, Division of Pharmaceutical Biosciences, Faculty of Pharmacy , University of Helsinki , Helsinki , Finland
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Rosa F, Sales KC, Cunha BR, Couto A, Lopes MB, Calado CRC. A comprehensive high-throughput FTIR spectroscopy-based method for evaluating the transfection event: estimating the transfection efficiency and extracting associated metabolic responses. Anal Bioanal Chem 2015; 407:8097-108. [PMID: 26329279 DOI: 10.1007/s00216-015-8983-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 07/29/2015] [Accepted: 08/14/2015] [Indexed: 12/11/2022]
Abstract
Reporter genes are routinely used in every laboratory for molecular and cellular biology for studying heterologous gene expression and general cellular biological mechanisms, such as transfection processes. Although well characterized and broadly implemented, reporter genes present serious limitations, either by involving time-consuming procedures or by presenting possible side effects on the expression of the heterologous gene or even in the general cellular metabolism. Fourier transform mid-infrared (FT-MIR) spectroscopy was evaluated to simultaneously analyze in a rapid (minutes) and high-throughput mode (using 96-wells microplates), the transfection efficiency, and the effect of the transfection process on the host cell biochemical composition and metabolism. Semi-adherent HEK and adherent AGS cell lines, transfected with the plasmid pVAX-GFP using Lipofectamine, were used as model systems. Good partial least squares (PLS) models were built to estimate the transfection efficiency, either considering each cell line independently (R (2) ≥ 0.92; RMSECV ≤ 2 %) or simultaneously considering both cell lines (R (2) = 0.90; RMSECV = 2 %). Additionally, the effect of the transfection process on the HEK cell biochemical and metabolic features could be evaluated directly from the FT-IR spectra. Due to the high sensitivity of the technique, it was also possible to discriminate the effect of the transfection process from the transfection reagent on KEK cells, e.g., by the analysis of spectral biomarkers and biochemical and metabolic features. The present results are far beyond what any reporter gene assay or other specific probe can offer for these purposes.
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Affiliation(s)
- Filipa Rosa
- Faculdade de Engenharia, Universidade Católica Portuguesa, Estrada Otávio Pato, 2635-631, Rio de Mouro, Portugal
| | - Kevin C Sales
- Faculdade de Engenharia, Universidade Católica Portuguesa, Estrada Otávio Pato, 2635-631, Rio de Mouro, Portugal
| | - Bernardo R Cunha
- Faculdade de Engenharia, Universidade Católica Portuguesa, Estrada Otávio Pato, 2635-631, Rio de Mouro, Portugal
| | - Andreia Couto
- Faculdade de Engenharia, Universidade Católica Portuguesa, Estrada Otávio Pato, 2635-631, Rio de Mouro, Portugal
| | - Marta B Lopes
- Faculdade de Engenharia, Universidade Católica Portuguesa, Estrada Otávio Pato, 2635-631, Rio de Mouro, Portugal.,Instituto de Telecomunicações, Instituto Superior Técnico, 1049-001, Lisbon, Portugal
| | - Cecília R C Calado
- Instituto Superior de Engenharia de Lisboa, Rua Conselheiro Emídio Navarro 1, 1959-007, Lisbon, Portugal.
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Nybond S, Karp M, Yrjönen T, Tammela P. Bioluminescent whole-cell reporter gene assays as screening tools in the identification of antimicrobial natural product extracts. J Microbiol Methods 2015; 114:54-6. [PMID: 25937087 DOI: 10.1016/j.mimet.2015.04.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 04/29/2015] [Accepted: 04/29/2015] [Indexed: 10/23/2022]
Abstract
We describe novel tools, bioluminescent whole-cell reporter gene assays, for facilitating the use of natural products in antimicrobial drug discovery. As proof-of-concept, a plant extract library was screened and follow-up experiments were carried out. Primary results can be obtained in 2-4h with high sensitivity, leading to significant improvements of the process.
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Affiliation(s)
- Susanna Nybond
- Centre for Drug Research, Division of Pharmaceutical Biosciences, University of Helsinki, Helsinki, Finland
| | - Matti Karp
- Department of Chemistry and Bioengineering, Tampere University of Technology, Tampere, Finland
| | - Teijo Yrjönen
- Centre for Drug Research, Division of Pharmaceutical Biosciences, University of Helsinki, Helsinki, Finland
| | - Päivi Tammela
- Centre for Drug Research, Division of Pharmaceutical Biosciences, University of Helsinki, Helsinki, Finland.
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Nybond S, Ghemtio L, Nawrot DA, Karp M, Xhaard H, Tammela P. Integrated In Vitro–In Silico Screening Strategy for the Discovery of Antibacterial Compounds. Assay Drug Dev Technol 2015; 13:25-33. [DOI: 10.1089/adt.2014.625] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Affiliation(s)
- Susanna Nybond
- Centre for Drug Research, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Leo Ghemtio
- Centre for Drug Research, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Dorota A. Nawrot
- Centre for Drug Research, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Matti Karp
- Department of Chemistry and Bioengineering, Tampere University of Technology, Tampere, Finland
| | - Henri Xhaard
- Centre for Drug Research, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
- Division of Pharmaceutical Chemistry and Technology, University of Helsinki, Helsinki, Finland
| | - Päivi Tammela
- Centre for Drug Research, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
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