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Vicente ED, Figueiredo D, Alves C. Toxicity of particulate emissions from residential biomass combustion: An overview of in vitro studies using cell models. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 927:171999. [PMID: 38554951 DOI: 10.1016/j.scitotenv.2024.171999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 03/07/2024] [Accepted: 03/24/2024] [Indexed: 04/02/2024]
Abstract
This article aims to critically review the current state of knowledge on in vitro toxicological assessments of particulate emissions from residential biomass heating systems. The review covers various aspects of particulate matter (PM) toxicity, including oxidative stress, inflammation, genotoxicity, and cytotoxicity, all of which have important implications for understanding the development of diseases. Studies in this field have highlighted the different mechanisms that biomass combustion particles activate, which vary depending on the combustion appliances and fuels. In general, particles from conventional combustion appliances are more potent in inducing cytotoxicity, DNA damage, inflammatory responses, and oxidative stress than those from modern appliances. The sensitivity of different cell lines to the toxic effects of biomass combustion particles is also influenced by cell type and culture conditions. One of the main challenges in this field is the considerable variation in sampling strategies, sample processing, experimental conditions, assays, and extraction techniques used in biomass burning PM studies. Advanced culture systems, such as co-cultures and air-liquid interface exposures, can provide more accurate insights into the effects of biomass combustion particles compared to simpler submerged monocultures. This review provides critical insights into the complex field of toxicity from residential biomass combustion emissions, underscoring the importance of continued research and standardisation of methodologies to better understand the associated health hazards and to inform targeted interventions.
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Affiliation(s)
- E D Vicente
- Department of Environment and Planning, Centre for Environmental and Marine Studies (CESAM), University of Aveiro, 3810-193 Aveiro, Portugal
| | - D Figueiredo
- Department of Environment and Planning, Centre for Environmental and Marine Studies (CESAM), University of Aveiro, 3810-193 Aveiro, Portugal; Department of Biology, Centre for Environmental and Marine Studies, University of Aveiro, 3810-193 Aveiro, Portugal
| | - C Alves
- Department of Environment and Planning, Centre for Environmental and Marine Studies (CESAM), University of Aveiro, 3810-193 Aveiro, Portugal.
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2
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Crooks I, Clements J, Curren R, Guo X, Hollings M, Lloyd M, Smart D, Thorne D, Weber E, Moore M. Key Challenges for In Vitro Testing of Tobacco Products for Regulatory Applications: Recommendations for the In Vitro Mouse Lymphoma Assay. Altern Lab Anim 2024; 52:42-59. [PMID: 38055860 DOI: 10.1177/02611929231219153] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2023]
Abstract
The Institute for In Vitro Sciences (IIVS) is sponsoring a series of workshops to develop recommendations for optimal scientific and technical approaches for conducting in vitro assays to assess potential toxicity within and across traditional tobacco and various tobacco and nicotine next-generation products (NGPs), including Heated Tobacco Products (HTPs) and Electronic Nicotine Delivery Systems (ENDS). This report was developed by a working group composed of attendees of the seventh IIVS workshop, 'Approaches and recommendations for conducting the mouse lymphoma gene mutation assay (MLA) and introduction to in vitro disease models', which was held virtually on 21-23 June 2022. This publication provides a background overview of the MLA, and includes the description of assay conduct and data interpretation, key challenges and recommended best practices for evaluating tobacco and nicotine products, with a focus on the evaluation of NGPs, and a summary of how the assay has been used to evaluate and compare tobacco and nicotine products.
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Affiliation(s)
- Ian Crooks
- B.A.T. (Investments) Limited, Southampton, UK
| | | | - Rodger Curren
- Institute for In Vitro Sciences, Gaithersburg, MD, USA
| | - Xiaoqing Guo
- National Center for Toxicological Research, Jefferson, AR, USA
| | | | - Mel Lloyd
- Labcorp Early Development Services, Harrogate, UK
| | - Daniel Smart
- Philip Morris International R&D, Philip Morris Products S.A., Neuchatel, Switzerland
| | | | - Elisabeth Weber
- Oekolab Ges. F. Umweltanalytik, A member of the JT International Group of Companies, Vienna, Austria
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Malach P, Kay C, Tinworth C, Patel F, Joosse B, Wade J, Rosa do Carmo M, Donovan B, Brugman M, Montiel-Equihua C, Francis N. Identification of a small molecule for enhancing lentiviral transduction of T cells. Mol Ther Methods Clin Dev 2023; 31:101113. [PMID: 37790244 PMCID: PMC10544093 DOI: 10.1016/j.omtm.2023.101113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 09/13/2023] [Indexed: 10/05/2023]
Abstract
Genetic modification of cells using viral vectors has shown huge therapeutic benefit in multiple diseases. However, inefficient transduction contributes to the high cost of these therapies. Several transduction-enhancing small molecules have previously been identified; however, some may be toxic to the cells or patient, otherwise alter cellular characteristics, or further increase manufacturing complexity. In this study, we aimed to identify molecules capable of enhancing lentiviral transduction of T cells from available small-molecule libraries. We conducted a high-throughput flow-cytometry-based screen of 27,892 compounds, which subsequently was narrowed down to six transduction-enhancing small molecules for further testing with two therapeutic lentiviral vectors used to manufacture GSK's clinical T cell therapy products. We demonstrate enhanced transduction without a negative impact on other product attributes. Furthermore, we present results of transcriptomic analysis, suggesting alteration of ribosome biogenesis, resulting in reduced interferon response, as a potential mechanism of action for the transduction-enhancing activity of the lead compound. Finally, we demonstrate the ability of the lead transduction enhancer to produce a comparable T cell product using a 3-fold reduction in vector volume in our clinical manufacturing process, resulting in a predicted 15% reduction in the overall cost of goods.
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Affiliation(s)
- Paulina Malach
- Product Development, Cell and Gene Therapy, GSK Medicine Research Centre, Stevenage, Hertfordshire SG1 2NY, UK
| | - Charlotte Kay
- Product Development, Cell and Gene Therapy, GSK Medicine Research Centre, Stevenage, Hertfordshire SG1 2NY, UK
| | - Chris Tinworth
- Medicinal Chemistry, Medicine Design, GSK Medicine Research Centre, Stevenage, Hertfordshire SG1 2NY, UK
| | - Florence Patel
- Screening, Profiling and Molecular Biology, Medicine Design, GSK Upper Providence, Collegeville, PA 19426, USA
| | - Bryan Joosse
- Screening, Profiling and Molecular Biology, Medicine Design, GSK Upper Providence, Collegeville, PA 19426, USA
| | - Jennifer Wade
- Product Development, Cell and Gene Therapy, GSK Medicine Research Centre, Stevenage, Hertfordshire SG1 2NY, UK
| | - Marlene Rosa do Carmo
- Product Development, Cell and Gene Therapy, GSK Medicine Research Centre, Stevenage, Hertfordshire SG1 2NY, UK
| | - Brian Donovan
- Screening, Profiling and Molecular Biology, Medicine Design, GSK Upper Providence, Collegeville, PA 19426, USA
| | - Martijn Brugman
- Analytical Development, Cell and Gene Therapy, GSK Medicine Research Centre, Stevenage, Hertfordshire SG1 2NY, UK
| | - Claudia Montiel-Equihua
- Product Development, Cell and Gene Therapy, GSK Medicine Research Centre, Stevenage, Hertfordshire SG1 2NY, UK
| | - Natalie Francis
- Product Development, Cell and Gene Therapy, GSK Medicine Research Centre, Stevenage, Hertfordshire SG1 2NY, UK
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Sandoval-Herrera N, Castillo JP, Ching MEA, Herrera M LG, Faure PA, Welch K. Non-destructive methods to assess pesticide exposure in free-living bats. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 870:162011. [PMID: 36737017 DOI: 10.1016/j.scitotenv.2023.162011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 12/20/2022] [Accepted: 01/30/2023] [Indexed: 06/18/2023]
Abstract
Bat populations are dwindling worldwide due to anthropogenic activities like agriculture, however the role that pesticide exposure plays on these declines is unclear. To address these research gaps, we first need to develop reliable methods to detect and monitor exposure to environmental pollutants and its effects on free-living bats. The use of biomarkers is a sensitive and informative tool to study sublethal effects in wildlife, however it requires laboratory validation and integrative approaches to be applicable to free-living species. In this study, we propose a set of non-destructive biomarkers to evaluate pesticide exposure in free-ranging bats and validated their suitability with dose-exposure experiments in captivity. We selected three biomarkers that have been widely used in vertebrate ecotoxicology and that combined represent sensitive, specific, and ecologically relevant responses to pollutants: DNA damage, AChE activity, and leukocyte profiles. We used two insectivorous bat species as model species Eptesicus fuscus (laboratory) and Pteronotus mexicanus (field). We found that micronuclei frequency (genotoxicity) and AChE activity (exposure and neurotoxicity) were robust indicators of toxicant exposure. The validity of this set of endpoints was supported by their consistent performance in laboratory and field experiments as well as by the significant correlation among them. Leukocyte profile (systemic stress) results were not consistent between laboratory and field studies, suggesting further evaluation of its suitability is needed. Integrative approaches, like the one we used here, maximize the insights about toxicant effects by combining the information of single biomarkers into more meaningful inferences, which can be applied to environmental risk assessments in wildlife. Furthermore, the use of non-destructive, cost-effective biomarkers is imperative when assessing toxicant exposure and effects in vulnerable wildlife and it should be a priority in the field of wildlife toxicology.
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Affiliation(s)
- Natalia Sandoval-Herrera
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada; Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada.
| | - Jesusa Paz Castillo
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Ma Enrica Angela Ching
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - L Gerardo Herrera M
- Estación de Biología Chamela, Instituto de Biología, Universidad Nacional Autónoma de México, San Patricio, Jalisco, Mexico
| | - Paul A Faure
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontario, Canada
| | - Kenneth Welch
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada; Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
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5
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Crosby ME, Ciurlionis R, Brayman TG, Kondratiuk A, Nicolette JJ. Exploring the molecular and functional cellular response to hydrazine via transcriptomics and DNA repair mutant cell lines. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2022; 63:336-350. [PMID: 36176055 PMCID: PMC9828720 DOI: 10.1002/em.22508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 09/23/2022] [Indexed: 05/04/2023]
Abstract
Hydrazine is a rodent carcinogen and is classified as a probable human carcinogen by IARC. Though hydrazine is positive in both in vitro and in vivo DNA strand break (comet) assays, hydrazine was reported to be negative in an in vitro mutation Muta Mouse lung epithelial cell (FE1) test, as well as in a regulatory-compliant, in vivo Big Blue mouse mutation test. In this article, mechanistic studies explored the cellular response to hydrazine. When tested in a regulatory-compliant mouse lymphoma assay, hydrazine yielded unusual, weakly positive results. This prompted an investigation into the transcriptional response to hydrazine in FE1 cells via RNA sequencing. Amongst the changes identified was a dose-dependent increase in G2/M DNA damage checkpoint activation associated genes. Flow cytometric experiments in FE1 cells revealed that hydrazine exposure led to S-phase cell cycle arrest. Clonogenic assays in a variety of cell lines harboring key DNA repair protein deficiencies indicated that hydrazine could sensitize cells lacking homology dependent repair proteins (Brca2 and Fancg). Lastly, hprt assays with hydrazine were conducted to determine whether a lack of DNA repair could lead to mutagenicity. However, no robust, dose-dependent induction of mutations was noted. The transcriptional and cell cycle response to hydrazine, coupled with functional investigations of DNA repair-deficient cell lines support the inconsistencies noted in the genetic toxicology regulatory battery. In summary, while hydrazine may be genotoxic, transcriptional and functional processes involved in cell cycle regulation and DNA repair appear to play a nuanced role in mediating the mutagenic potential.
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Affiliation(s)
- Meredith E. Crosby
- Pre‐Clinical Safety, AbbVie Inc.North ChicagoIllinoisUnited States
- Drug Safety and PharmacometricsRegeneron Pharmaceuticals Inc.TarrytownNew YorkUnited States
| | - Rita Ciurlionis
- Pre‐Clinical Safety, AbbVie Inc.North ChicagoIllinoisUnited States
| | | | | | - John J. Nicolette
- Pre‐Clinical Safety, AbbVie Inc.North ChicagoIllinoisUnited States
- Preclinical Sciences and Translational SafetyJanssen Research and DevelopmentRaritanNew JerseyUnited States
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Kullmann A, Kridner D, Mertens S, Christianson M, Rosa D, Diaz-Botia CA. First Food and Drug Administration Cleared Thin-Film Electrode for Intracranial Stimulation, Recording, and Monitoring of Brain Activity—Part 1: Biocompatibility Testing. Front Neurosci 2022; 16:876877. [PMID: 35573282 PMCID: PMC9100917 DOI: 10.3389/fnins.2022.876877] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 03/28/2022] [Indexed: 11/16/2022] Open
Abstract
Subdural strip and grid invasive electroencephalography electrodes are routinely used for surgical evaluation of patients with drug-resistant epilepsy (DRE). Although these electrodes have been in the United States market for decades (first FDA clearance 1985), their fabrication, materials, and properties have hardly changed. Existing commercially available electrodes are made of silicone, are thick (>0.5 mm), and do not optimally conform to brain convolutions. New thin-film polyimide electrodes (0.08 mm) have been manufactured to address these issues. While different thin-film electrodes are available for research use, to date, only one electrode is cleared by Food and Drug Administration (FDA) for use in clinical practice. This study describes the biocompatibility tests that led to this clearance. Biocompatibility was tested using standard methods according to International Organization for Standardization (ISO) 10993. Electrodes and appropriate control materials were bent, folded, and placed in the appropriate extraction vehicles, or implanted. The extracts were used for in vitro and in vivo tests, to assess the effects of any potential extractable and leachable materials that may be toxic to the body. In vitro studies included cytotoxicity tested in L929 cell line, genotoxicity tested using mouse lymphoma assay (MLA) and Ames assay, and hemolysis tested in rabbit whole blood samples. The results indicated that the electrodes were non-cytotoxic, non-mutagenic, non-clastogenic, and non-hemolytic. In vivo studies included sensitization tested in guinea pigs, irritation tested in rabbits, acute systemic toxicity testing in mice, pyrogenicity tested in rabbits, and a prolonged 28-day subdural implant in sheep. The results indicated that the electrodes induced no sensitization and irritation, no weight loss, and no temperature increase. Histological examination of the sheep brain tissue showed no or minimal immune cell accumulation, necrosis, neovascularization, fibrosis, and astrocyte infiltration, with no differences from the control material. In summary, biocompatibility studies indicated that these new thin-film electrodes are appropriate for human use. As a result, the electrodes were cleared by the FDA for use in clinical practice [510(k) K192764], making it the first thin-film subdural electrode to progress from research to clinic. Its readiness as a commercial product ensures availability to all patients undergoing surgical evaluation for DRE.
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Groff K, Evans SJ, Doak SH, Pfuhler S, Corvi R, Saunders S, Stoddart G. In vitro and integrated in vivo strategies to reduce animal use in genotoxicity testing. Mutagenesis 2021; 36:389-400. [PMID: 34555171 DOI: 10.1093/mutage/geab035] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 09/17/2021] [Indexed: 11/13/2022] Open
Abstract
Scientific, financial, and ethical drivers have led to unprecedented interest in implementing human-relevant, mechanistic in vitro and in silico testing approaches. Further, as non-animal approaches are being developed and validated, researchers are interested in strategies that can immediately reduce the use of animals in toxicology testing. Here, we aim to outline a testing strategy for assessing genotoxicity beginning with standard in vitro methods, such as the bacterial reverse mutation test and the in vitro micronucleus test, followed by a second tier of in vitro assays including those using advanced 3D tissue models. Where regulatory agencies require in vivo testing, one demonstrated strategy is to combine genotoxicity studies traditionally conducted separately into a single test or to integrate genotoxicity studies into other toxicity studies. Standard setting organisations and regulatory agencies have encouraged such strategies, and examples of their use can be found in the scientific literature. Employing approaches outlined here will reduce animal use as well as study time and costs.
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Affiliation(s)
- Katherine Groff
- PETA Science Consortium International e.V., Stuttgart, Germany
| | | | | | | | - Raffaella Corvi
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | | | - Gilly Stoddart
- PETA Science Consortium International e.V., Stuttgart, Germany
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8
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Pradeep P, Judson R, DeMarini DM, Keshava N, Martin TM, Dean J, Gibbons CF, Simha A, Warren SH, Gwinn MR, Patlewicz G. Evaluation of Existing QSAR Models and Structural Alerts and Development of New Ensemble Models for Genotoxicity Using a Newly Compiled Experimental Dataset. ACTA ACUST UNITED AC 2021; 18. [PMID: 34504984 DOI: 10.1016/j.comtox.2021.100167] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Regulatory agencies world-wide face the challenge of performing risk-based prioritization of thousands of substances in commerce. In this study, a major effort was undertaken to compile a large genotoxicity dataset (54,805 records for 9299 substances) from several public sources (e.g., TOXNET, COSMOS, eChemPortal). The names and outcomes of the different assays were harmonized, and assays were annotated by type: gene mutation in Salmonella bacteria (Ames assay) and chromosome mutation (clastogenicity) in vitro or in vivo (chromosome aberration, micronucleus, and mouse lymphoma Tk +/- assays). This dataset was then evaluated to assess genotoxic potential using a categorization scheme, whereby a substance was considered genotoxic if it was positive in at least one Ames or clastogen study. The categorization dataset comprised 8442 chemicals, of which 2728 chemicals were genotoxic, 5585 were not and 129 were inconclusive. QSAR models (TEST and VEGA) and the OECD Toolbox structural alerts/profilers (e.g., OASIS DNA alerts for Ames and chromosomal aberrations) were used to make in silico predictions of genotoxicity potential. The performance of the individual QSAR tools and structural alerts resulted in balanced accuracies of 57-73%. A Naïve Bayes consensus model was developed using combinations of QSAR models and structural alert predictions. The 'best' consensus model selected had a balanced accuracy of 81.2%, a sensitivity of 87.24% and a specificity of 75.20%. This in silico scheme offers promise as a first step in ranking thousands of substances as part of a prioritization approach for genotoxicity.
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Affiliation(s)
- Prachi Pradeep
- Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee, USA
- Center for Computational Toxicology and Exposure, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA
| | - Richard Judson
- Center for Computational Toxicology and Exposure, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA
| | - David M DeMarini
- Center for Computational Toxicology and Exposure, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA
| | - Nagalakshmi Keshava
- Center for Computational Toxicology and Exposure, U.S. Environmental Protection Agency, Cincinnati, Ohio, USA
| | - Todd M Martin
- Center for Computational Toxicology and Exposure, U.S. Environmental Protection Agency, Cincinnati, Ohio, USA
| | - Jeffry Dean
- Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Cincinnati, Ohio, USA
| | - Catherine F Gibbons
- Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Washington, District of Columbia, USA
| | - Anita Simha
- ORAU, contractor to U.S. Environmental Protection Agency through the National Student Services Contract, Research Triangle Park, North Carolina, USA
| | - Sarah H Warren
- Center for Computational Toxicology and Exposure, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA
| | - Maureen R Gwinn
- Center for Computational Toxicology and Exposure, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA
| | - Grace Patlewicz
- Center for Computational Toxicology and Exposure, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA
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Sandoval-Herrera N, Paz Castillo J, Herrera Montalvo LG, Welch KC. Micronucleus Test Reveals Genotoxic Effects in Bats Associated with Agricultural Activity. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2021; 40:202-207. [PMID: 33283353 DOI: 10.1002/etc.4907] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 09/28/2020] [Accepted: 10/13/2020] [Indexed: 06/12/2023]
Abstract
Bats play a vital role in our ecosystems and economies as natural pest-control agents, seed dispersers, and pollinators. Agricultural intensification, however, can impact bats foraging near crops, affecting the ecosystem services they provide. Exposure to pesticides, for example, may induce chromosome breakage or missegregation that can result in micronucleus formation. Detection of micronuclei is a simple, inexpensive, and relatively minimally invasive technique commonly used to evaluate chemical genotoxicity but rarely applied to assess wildlife genotoxic effects. We evaluated the suitability of the micronucleus test as a biomarker of genotoxicity for biomonitoring field studies in bats. We collected blood samples from insectivorous bats roosting in caves surrounded by different levels of disturbance (agriculture, human settlements) in Colima and Jalisco, west central Mexico. Then, we examined the frequency of micronucleus inclusions in erythrocytes using differentially stained blood smears. Bats from caves surrounded by proportionately more (53%) land used for agriculture and irrigated year-round had higher micronucleus frequency than bats from a less disturbed site (15% agriculture). We conclude that the micronucleus test is a sensitive method to evaluate genotoxic effects in free-ranging bats and could provide a useful biomarker for evaluating risk of exposure in wild populations. Environ Toxicol Chem 2021;40:202-207. © 2020 SETAC.
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Affiliation(s)
- Natalia Sandoval-Herrera
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
- Department of Biological Sciences, University of Toronto Scarborough, Scarborough, Ontario, Canada
| | - Jesusa Paz Castillo
- Department of Biological Sciences, University of Toronto Scarborough, Scarborough, Ontario, Canada
| | - L Gerardo Herrera Montalvo
- Estación de Biología Chamela, Instituto de Biología, Universidad Nacional Autónoma de México, San Patricio, Jalisco, Mexico
| | - Kenneth C Welch
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
- Department of Biological Sciences, University of Toronto Scarborough, Scarborough, Ontario, Canada
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Genotoxicity studies with an ethanolic extract of Kalanchoe pinnata leaves. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2020; 856-857:503229. [PMID: 32928369 DOI: 10.1016/j.mrgentox.2020.503229] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 06/28/2020] [Accepted: 07/07/2020] [Indexed: 11/23/2022]
Abstract
Kalanchoe pinnata is a medicinal plant, used mainly in African, Brazilian, and Indian traditional medicine for the treatment of several human disorders. Whole leaf extracts, crude juice of the leaves, and aqueous and organic extracts of the leaves are used. Over the last decade, ethanolic extracts have become the most popular form of Kalanchoe medicinal preparation. In this study, an ethanolic extract of this plant leaf was tested in a battery of standard regulatory genetic toxicology tests. This extract did not induce reverse mutations in the Salmonella/microsome assay but induces a weak genotoxic response in the mouse lymphoma assay and the in vivo micronucleus assay in mice. Our results indicate that this material may cause DNA damage, and its use should be restricted.
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11
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Pinter E, Rainer B, Czerny T, Riegel E, Schilter B, Marin-Kuan M, Tacker M. Evaluation of the Suitability of Mammalian In Vitro Assays to Assess the Genotoxic Potential of Food Contact Materials. Foods 2020; 9:foods9020237. [PMID: 32098342 PMCID: PMC7074469 DOI: 10.3390/foods9020237] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 02/12/2020] [Accepted: 02/19/2020] [Indexed: 01/25/2023] Open
Abstract
Background: Non-targeted screening of food contact materials (FCM) for non-intentionally added substances (NIAS) reveals a great number of unknown and unidentified substances present at low concentrations. In the absence of toxicological data, the application of the threshold of toxicological concern (TTC) or of EU Regulation 10/2011 requires methods able to fulfill safety threshold criteria. In this review, mammalian in vitro genotoxicity assays are analyzed for their ability to detect DNA-damaging substances at limits of biological detection (LOBD) corresponding to the appropriate safety thresholds. Results: The ability of the assays to detect genotoxic effects varies greatly between substance classes. Especially for direct-acting mutagens, the assays lacked the ability to detect most DNA reactive substances below the threshold of 10 ppb, making them unsuitable to pick up potential genotoxicants present in FCM migrates. However, suitability for the detection of chromosomal damage or investigation of other modes of action makes them a complementary tool as part of a standard test battery aimed at giving additional information to ensure safety. Conclusion: improvements are necessary to comply with regulatory thresholds to consider mammalian genotoxicity in vitro assays to assess FCM safety.
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Affiliation(s)
- Elisabeth Pinter
- Department of Applied Life Sciences, University of Applied Sciences, FH Campus Wien, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria
- Correspondence: ; Tel.: +43-1-606-6877-3584
| | - Bernhard Rainer
- Department of Applied Life Sciences, University of Applied Sciences, FH Campus Wien, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria
| | - Thomas Czerny
- Department of Applied Life Sciences, University of Applied Sciences, FH Campus Wien, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria
| | - Elisabeth Riegel
- Department of Applied Life Sciences, University of Applied Sciences, FH Campus Wien, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria
| | - Benoît Schilter
- Nestlé Research Center, Route du Jorat 57, 1000 Lausanne, Switzerland
| | | | - Manfred Tacker
- Department of Applied Life Sciences, University of Applied Sciences, FH Campus Wien, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria
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12
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Analysis of In Vivo Mutation in the Hprt and Tk Genes of Mouse Lymphocytes. Methods Mol Biol 2020. [PMID: 31989565 DOI: 10.1007/978-1-0716-0223-2_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Determining mutant frequencies in endogenous reporter genes is a tool for identifying potentially genotoxic environmental agents, and discovering phenotypes prone to genomic instability and diseases, such as cancer. Here, we describe a high-throughput method for identifying mouse spleen lymphocytes with mutations in the endogenous X-linked hypoxanthine guanine phosphoribosyl transferase (Hprt) gene and the endogenous autosomal thymidine kinase (Tk) gene. The selective clonal expansion of mutant lymphocytes is based upon the phenotypic properties of HPRT- and TK-deficient cells. The same procedure can be utilized for quantifying Hprt mutations in most strains of mice (and, with minor changes, in other mammalian species), while mutations in the Tk gene can be determined only in transgenic mice that are heterozygous for inactivation of this gene. Expanded mutant clones can be further analyzed to classify the types of mutations in the Tk gene (small intragenic mutations vs. large chromosomal mutations) and to determine the nature of intragenic mutation at both the Hprt and Tk genes.
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13
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Albulescu R, Popa AC, Enciu AM, Albulescu L, Dudau M, Popescu ID, Mihai S, Codrici E, Pop S, Lupu AR, Stan GE, Manda G, Tanase C. Comprehensive In Vitro Testing of Calcium Phosphate-Based Bioceramics with Orthopedic and Dentistry Applications. MATERIALS 2019; 12:ma12223704. [PMID: 31717621 PMCID: PMC6888321 DOI: 10.3390/ma12223704] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 10/29/2019] [Accepted: 11/05/2019] [Indexed: 02/07/2023]
Abstract
Recently, a large spectrum of biomaterials emerged, with emphasis on various pure, blended, or doped calcium phosphates (CaPs). Although basic cytocompatibility testing protocols are referred by International Organization for Standardization (ISO) 10993 (parts 1-22), rigorous in vitro testing using cutting-edge technologies should be carried out in order to fully understand the behavior of various biomaterials (whether in bulk or low-dimensional object form) and to better gauge their outcome when implanted. In this review, current molecular techniques are assessed for the in-depth characterization of angiogenic potential, osteogenic capability, and the modulation of oxidative stress and inflammation properties of CaPs and their cation- and/or anion-substituted derivatives. Using such techniques, mechanisms of action of these compounds can be deciphered, highlighting the signaling pathway activation, cross-talk, and modulation by microRNA expression, which in turn can safely pave the road toward a better filtering of the truly functional, application-ready innovative therapeutic bioceramic-based solutions.
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Affiliation(s)
- Radu Albulescu
- Victor Babes National Institute of Pathology, Biochemistry-Proteomics Department, 050096 Bucharest, Romania; (R.A.); (L.A.); (M.D.); (I.D.P.); (S.M.); (E.C.); (S.P.); (A.-R.L.); (G.M.)
- Department Pharmaceutical Biotechnology, National Institute for Chemical-Pharmaceutical R&D, 031299, Bucharest, Romania
| | - Adrian-Claudiu Popa
- National Institute of Materials Physics, 077125 Magurele, Romania (G.E.S.)
- Army Centre for Medical Research, 010195 Bucharest, Romania
| | - Ana-Maria Enciu
- Victor Babes National Institute of Pathology, Biochemistry-Proteomics Department, 050096 Bucharest, Romania; (R.A.); (L.A.); (M.D.); (I.D.P.); (S.M.); (E.C.); (S.P.); (A.-R.L.); (G.M.)
- Department of Cellular and Molecular Biology and Histology, Carol Davila University of Medicine and Pharmacy, 050047 Bucharest, Romania
| | - Lucian Albulescu
- Victor Babes National Institute of Pathology, Biochemistry-Proteomics Department, 050096 Bucharest, Romania; (R.A.); (L.A.); (M.D.); (I.D.P.); (S.M.); (E.C.); (S.P.); (A.-R.L.); (G.M.)
| | - Maria Dudau
- Victor Babes National Institute of Pathology, Biochemistry-Proteomics Department, 050096 Bucharest, Romania; (R.A.); (L.A.); (M.D.); (I.D.P.); (S.M.); (E.C.); (S.P.); (A.-R.L.); (G.M.)
- Department of Cellular and Molecular Biology and Histology, Carol Davila University of Medicine and Pharmacy, 050047 Bucharest, Romania
| | - Ionela Daniela Popescu
- Victor Babes National Institute of Pathology, Biochemistry-Proteomics Department, 050096 Bucharest, Romania; (R.A.); (L.A.); (M.D.); (I.D.P.); (S.M.); (E.C.); (S.P.); (A.-R.L.); (G.M.)
| | - Simona Mihai
- Victor Babes National Institute of Pathology, Biochemistry-Proteomics Department, 050096 Bucharest, Romania; (R.A.); (L.A.); (M.D.); (I.D.P.); (S.M.); (E.C.); (S.P.); (A.-R.L.); (G.M.)
| | - Elena Codrici
- Victor Babes National Institute of Pathology, Biochemistry-Proteomics Department, 050096 Bucharest, Romania; (R.A.); (L.A.); (M.D.); (I.D.P.); (S.M.); (E.C.); (S.P.); (A.-R.L.); (G.M.)
| | - Sevinci Pop
- Victor Babes National Institute of Pathology, Biochemistry-Proteomics Department, 050096 Bucharest, Romania; (R.A.); (L.A.); (M.D.); (I.D.P.); (S.M.); (E.C.); (S.P.); (A.-R.L.); (G.M.)
| | - Andreea-Roxana Lupu
- Victor Babes National Institute of Pathology, Biochemistry-Proteomics Department, 050096 Bucharest, Romania; (R.A.); (L.A.); (M.D.); (I.D.P.); (S.M.); (E.C.); (S.P.); (A.-R.L.); (G.M.)
- Cantacuzino National Medico-Military Institute for Research and Development, 050096 Bucharest, Romania
| | - George E. Stan
- National Institute of Materials Physics, 077125 Magurele, Romania (G.E.S.)
| | - Gina Manda
- Victor Babes National Institute of Pathology, Biochemistry-Proteomics Department, 050096 Bucharest, Romania; (R.A.); (L.A.); (M.D.); (I.D.P.); (S.M.); (E.C.); (S.P.); (A.-R.L.); (G.M.)
| | - Cristiana Tanase
- Victor Babes National Institute of Pathology, Biochemistry-Proteomics Department, 050096 Bucharest, Romania; (R.A.); (L.A.); (M.D.); (I.D.P.); (S.M.); (E.C.); (S.P.); (A.-R.L.); (G.M.)
- Cajal Institute, Titu Maiorescu University, 004051 Bucharest, Romania
- Correspondence:
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14
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Dusinska M, Mariussen E, Rundén-Pran E, Hudecova AM, Elje E, Kazimirova A, El Yamani N, Dommershausen N, Tharmann J, Fieblinger D, Herzberg F, Luch A, Haase A. In Vitro Approaches for Assessing the Genotoxicity of Nanomaterials. Methods Mol Biol 2019; 1894:83-122. [PMID: 30547457 DOI: 10.1007/978-1-4939-8916-4_6] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Genotoxicity is associated with serious health effects and includes different types of DNA lesions, gene mutations, structural chromosome aberrations involving breakage and/or rearrangements of chromosomes (referred to as clastogenicity) and numerical chromosome aberrations (referred to as aneuploidy). Assessing the potential genotoxic properties of chemicals, including nanomaterials (NMs), is a key element in regulatory safety assessment. State-of-the-art genotoxicity testing includes a battery of assays covering gene mutations, structural and numerical chromosome aberrations. Typically various in vitro assays are performed in the first tier. It is not very likely that NMs may induce as yet unknown types of genotoxic damage beyond what is already known for chemicals. Thus, principles of genotoxicity testing as established for chemicals should be applicable to NMs as well. However, established test guidelines (i.e., OECD TG) may require adaptations for NM testing, as currently under discussion at the OECD. This chapter gives an overview of genotoxicity testing of NMs in vitro based on experiences from various research projects. We recommend a combination of a mammalian gene mutation assay (at either Tk or HPRT locus), the in vitro comet assay, and the cytokinesis-block micronucleus assay, which are discussed in detail here. In addition we also include the Cell Transformation Assay (CTA) as a promising novel test for predicting NM-induced cell transformation in vitro.
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Affiliation(s)
- Maria Dusinska
- Health Effects Laboratory, Department of Environmental Chemistry, Norwegian Institute for Air Research (NILU), Kjeller, Norway.
| | - Espen Mariussen
- Health Effects Laboratory, Department of Environmental Chemistry, Norwegian Institute for Air Research (NILU), Kjeller, Norway
| | - Elise Rundén-Pran
- Health Effects Laboratory, Department of Environmental Chemistry, Norwegian Institute for Air Research (NILU), Kjeller, Norway
| | - Alexandra Misci Hudecova
- Health Effects Laboratory, Department of Environmental Chemistry, Norwegian Institute for Air Research (NILU), Kjeller, Norway
| | - Elisabeth Elje
- Health Effects Laboratory, Department of Environmental Chemistry, Norwegian Institute for Air Research (NILU), Kjeller, Norway
| | - Alena Kazimirova
- Health Effects Laboratory, Department of Environmental Chemistry, Norwegian Institute for Air Research (NILU), Kjeller, Norway
| | - Naouale El Yamani
- Health Effects Laboratory, Department of Environmental Chemistry, Norwegian Institute for Air Research (NILU), Kjeller, Norway
| | - Nils Dommershausen
- Department of Chemical and Product Safety, German Federal Institute for Risk Assessment (BfR), Berlin, Germany
| | - Julian Tharmann
- Department of Chemical and Product Safety, German Federal Institute for Risk Assessment (BfR), Berlin, Germany
| | - Dagmar Fieblinger
- Department of Chemical and Product Safety, German Federal Institute for Risk Assessment (BfR), Berlin, Germany
| | - Frank Herzberg
- Department of Chemical and Product Safety, German Federal Institute for Risk Assessment (BfR), Berlin, Germany
| | - Andreas Luch
- Department of Chemical and Product Safety, German Federal Institute for Risk Assessment (BfR), Berlin, Germany
| | - Andrea Haase
- Department of Chemical and Product Safety, German Federal Institute for Risk Assessment (BfR), Berlin, Germany.
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15
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A comparison of in vitro cytotoxicity assays in medical device regulatory studies. Regul Toxicol Pharmacol 2018; 97:24-32. [PMID: 29885342 DOI: 10.1016/j.yrtph.2018.06.003] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 06/05/2018] [Indexed: 11/20/2022]
Abstract
Medical device biocompatibility testing is used to evaluate the risk of adverse effects on tissues from exposure to leachates/extracts. A battery of tests is typically recommended in accordance with regulatory standards to determine if the device is biocompatible. In vitro cytotoxicity, a key element of the standards, is a required endpoint for all types of medical devices. Each validated cytotoxicity method has different methodology and acceptance criteria that could influence the selection of a specific test. In addition, some guidances are more specific than others as to the recommended test methods. For example, the International Organization for Standardization (ISO1) cites preference for quantitative methods (e.g., tetrazolium (MTT/XTT), neutral red (NR), or colony formation assays (CFA)) over qualitative methods (e.g., elution, agar overlay/diffusion, or direct), while a recent ISO standard for contact lens/lens care solutions specifically requires a qualitative direct test. Qualitative methods are described in United States Pharmacopeia (USP) while quantitative CFAs are listed in Japan guidance. The aim of this review is to compare the methodologies such as test article preparation, test conditions, and criteria for six cytotoxicity methods recommended in regulatory standards in order to inform decisions on which method(s) to select during the medical device safety evaluation.
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16
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Suh M, Proctor D, Chappell G, Rager J, Thompson C, Borghoff S, Finch L, Ellis-Hutchings R, Wiench K. A review of the genotoxic, mutagenic, and carcinogenic potentials of several lower acrylates. Toxicology 2018; 402-403:50-67. [PMID: 29689363 DOI: 10.1016/j.tox.2018.04.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 03/28/2018] [Accepted: 04/19/2018] [Indexed: 01/29/2023]
Abstract
Lower alkyl acrylate monomers include methyl-, ethyl-, n-butyl-, and 2-ethylhexyl acrylate. These acrylates are used in the manufacture of acrylic polymers and copolymers for plastics, food packaging, adhesives, and cosmetic formulations. Although there is limited potential for human environmental exposure, occupational exposure can occur via inhalation and dermal contact. Recently, new genotoxicity data have been generated, along with in silico and in vitro read-cross analyses, for these acrylates. The availability of high-throughput screening (HTS) data through the ToxCast™/Tox21 databases allows for consideration of computational toxicology and organization of these data according to the ten key characteristics of carcinogens. Therefore, we conducted a comprehensive review to evaluate the mechanistic, toxicokinetic, animal, and human data, including HTS data, for characterizing the potential carcinogenicity, mutagenicity, and genotoxicity of these acrylates. Toxicokinetic data demonstrate that these acrylates are metabolized rapidly by carboxylesterase hydrolysis and conjugation with glutathione. HTS data demonstrated an overall lack of bioactivity in cancer-related pathways. Overall, the genotoxicity and mutagenicity data support a cytotoxic, non-genotoxic mechanism for these acrylates. Cancer bioassay studies conducted by the oral, dermal, and inhalation routes in animal models with these acrylates did not show any increase in tumor incidence, with two exceptions. At high doses, and secondary to chronic site-of-contact irritation and corrosion, rodent forestomach tumors were induced by oral gavage dosing with ethyl acrylate, and skin tumors were observed following chronic dermal dosing with 2-ethylhexyl acrylate in C3H/HeJ inbred mice (a strain with deficiencies in wound healing), but not in the outbred NMRI strain. For both dermal and forestomach cancers, tumorigenesis is secondary to high doses and long-term tissue damage, shown to be reversible. With evidence that these chemicals are not genotoxic, and that they cause forestomach and dermal tumors through chronic irritation and regenerative proliferation mechanisms, these acrylates are unlikely to pose a human cancer hazard.
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Affiliation(s)
- Mina Suh
- ToxStrategies, Inc., Mission Viejo, CA 92692, United States
| | | | | | - Julia Rager
- ToxStrategies, Inc., Austin, TX 78759, United States
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17
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Nakatsuji T, Chen TH, Butcher AM, Trzoss LL, Nam SJ, Shirakawa KT, Zhou W, Oh J, Otto M, Fenical W, Gallo RL. A commensal strain of Staphylococcus epidermidis protects against skin neoplasia. SCIENCE ADVANCES 2018; 4:eaao4502. [PMID: 29507878 PMCID: PMC5834004 DOI: 10.1126/sciadv.aao4502] [Citation(s) in RCA: 156] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 01/24/2018] [Indexed: 05/04/2023]
Abstract
We report the discovery that strains of Staphylococcus epidermidis produce 6-N-hydroxyaminopurine (6-HAP), a molecule that inhibits DNA polymerase activity. In culture, 6-HAP selectively inhibited proliferation of tumor lines but did not inhibit primary keratinocytes. Resistance to 6-HAP was associated with the expression of mitochondrial amidoxime reducing components, enzymes that were not observed in cells sensitive to this compound. Intravenous injection of 6-HAP in mice suppressed the growth of B16F10 melanoma without evidence of systemic toxicity. Colonization of mice with an S. epidermidis strain producing 6-HAP reduced the incidence of ultraviolet-induced tumors compared to mice colonized by a control strain that did not produce 6-HAP. S. epidermidis strains producing 6-HAP were found in the metagenome from multiple healthy human subjects, suggesting that the microbiome of some individuals may confer protection against skin cancer. These findings show a new role for skin commensal bacteria in host defense.
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Affiliation(s)
- Teruaki Nakatsuji
- Department of Dermatology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Tiffany H. Chen
- Department of Dermatology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Anna M. Butcher
- Department of Dermatology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Lynnie L. Trzoss
- Scripps Institute of Oceanography, University of California, San Diego, La Jolla, CA 92093, USA
| | - Sang-Jip Nam
- Scripps Institute of Oceanography, University of California, San Diego, La Jolla, CA 92093, USA
| | - Karina T. Shirakawa
- Department of Dermatology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Wei Zhou
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA
| | - Julia Oh
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA
| | - Michael Otto
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - William Fenical
- Scripps Institute of Oceanography, University of California, San Diego, La Jolla, CA 92093, USA
| | - Richard L. Gallo
- Department of Dermatology, University of California, San Diego, La Jolla, CA 92093, USA
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18
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Development of a quantitative cytotoxicity assay using mouse lymphoma TK cells. Toxicol In Vitro 2017; 45:172-180. [DOI: 10.1016/j.tiv.2017.09.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 08/10/2017] [Accepted: 09/04/2017] [Indexed: 11/21/2022]
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19
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Brass DM, Palmer SM. Models of toxicity of diacetyl and alternative diones. Toxicology 2017; 388:15-20. [PMID: 28232124 PMCID: PMC5540796 DOI: 10.1016/j.tox.2017.02.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 01/23/2017] [Accepted: 02/17/2017] [Indexed: 11/28/2022]
Abstract
Diacetyl (DA; 2,3-butanedione), with the chemical formula (CH3CO)2 is a volatile organic compound with a deep yellow color and a strong buttery flavor and aroma. These properties have made DA a particularly useful and common food flavoring ingredient. However, because of this increased occupational use, workers can be exposed to high vapor concentrations in the workplace. Despite being listed by the USFDA to be 'generally regarded as safe' (GRAS), multiple lines of evidence suggest that exposure to high concentrations of DA vapor causes long-term impairments in lung function with lung function testing indicating evidence of either restrictive or obstructive airway narrowing in affected individuals. A growing number of pre-clinical studies have now addressed the short and long-term toxicity associated with DA exposure providing further insight into the toxicity of DA and related diones. This review summarizes these observations.
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Affiliation(s)
- David M Brass
- Division of Pulmonary, Allergy, and Critical Care Medicine, Duke University Medical Center, Durham, NC, USA.
| | - Scott M Palmer
- Division of Pulmonary, Allergy, and Critical Care Medicine, Duke University Medical Center, Durham, NC, USA
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20
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Basarab GS, Doig P, Galullo V, Kern G, Kimzey A, Kutschke A, Newman JP, Morningstar M, Mueller J, Otterson L, Vishwanathan K, Zhou F, Gowravaram M. Discovery of Novel DNA Gyrase Inhibiting Spiropyrimidinetriones: Benzisoxazole Fusion with N-Linked Oxazolidinone Substituents Leading to a Clinical Candidate (ETX0914). J Med Chem 2015; 58:6264-82. [PMID: 26158756 DOI: 10.1021/acs.jmedchem.5b00863] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A novel class of bacterial type-II topoisomerase inhibitor displaying a spiropyrimidinetrione architecture fused to a benzisoxazole scaffold shows potent activity against Gram-positive and fastidious Gram-negative bacteria. Here, we describe a series of N-linked oxazolidinone substituents on the benzisoxazole that improve upon the antibacterial activity of initially described compounds of the class, show favorable PK properties, and demonstrate efficacy in an in vivo Staphylococcus aureus infection model. Inhibition of the topoisomerases DNA gyrase and topoisomerase IV from both Gram-positive and a Gram-negative organisms was demonstrated. Compounds showed a clean in vitro toxicity profile, including no genotoxicity and no bone marrow toxicity at the highest evaluated concentrations or other issues that have been problematic for some fluoroquinolones. Compound 1u was identified for advancement into human clinical trials for treatment of uncomplicated gonorrhea based on a variety of beneficial attributes including the potent activity and the favorable safety profile.
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21
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Analysis of in vivo mutation in the Hprt and Tk genes of mouse lymphocytes. Methods Mol Biol 2014; 1105:255-70. [PMID: 24623234 DOI: 10.1007/978-1-62703-739-6_20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Assays measuring mutant frequencies in endogenous reporter genes are used for identifying potentially genotoxic environmental agents and discovering phenotypes prone to genomic instability and diseases, such as cancer. Here, we describe methods for identifying mouse spleen lymphocytes with mutations in the endogenous X-linked hypoxanthine guanine phosphoribosyl transferase (Hprt) gene and the endogenous autosomal thymidine kinase (Tk) gene. The selective clonal expansion of mutant lymphocytes is based upon the phenotypic properties of HPRT- and TK-deficient cells. The same procedure can be utilized for quantifying Hprt mutations in most strains of mice (and, with minor changes, in other mammalian species), while mutations in the Tk gene can be determined only in transgenic mice that are heterozygous for inactivation of this gene. Expanded mutant clones can be further analyzed to classify the types of mutations in the Tk gene (small intragenic mutations vs. large chromosomal mutations) and to determine the nature of intragenic mutation in both the Hprt and Tk genes.
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22
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Basarab GS, Hill PJ, Garner CE, Hull K, Green O, Sherer BA, Dangel PB, Manchester JI, Bist S, Hauck S, Zhou F, Uria-Nickelsen M, Illingworth R, Alm R, Rooney M, Eakin AE. Optimization of pyrrolamide topoisomerase II inhibitors toward identification of an antibacterial clinical candidate (AZD5099). J Med Chem 2014; 57:6060-82. [PMID: 24959892 DOI: 10.1021/jm500462x] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
AZD5099 (compound 63) is an antibacterial agent that entered phase 1 clinical trials targeting infections caused by Gram-positive and fastidious Gram-negative bacteria. It was derived from previously reported pyrrolamide antibacterials and a fragment-based approach targeting the ATP binding site of bacterial type II topoisomerases. The program described herein varied a 3-piperidine substituent and incorporated 4-thiazole substituents that form a seven-membered ring intramolecular hydrogen bond with a 5-position carboxylic acid. Improved antibacterial activity and lower in vivo clearances were achieved. The lower clearances were attributed, in part, to reduced recognition by the multidrug resistant transporter Mrp2. Compound 63 showed notable efficacy in a mouse neutropenic Staphylococcus aureus infection model. Resistance frequency versus the drug was low, and reports of clinical resistance due to alteration of the target are few. Hence, 63 could offer a novel treatment for serious issues of resistance to currently used antibacterials.
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Affiliation(s)
- Gregory S Basarab
- Infection Innovative Medicines, AstraZeneca R&D Boston , 35 Gatehouse Drive, Waltham, Massachusetts 02451, United States
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23
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Cheng TF, Patton GW, Muldoon-Jacobs K. Can the L5178Y Tk+/- mouse lymphoma assay detect epigenetic silencing? Food Chem Toxicol 2013; 59:187-90. [PMID: 23778052 DOI: 10.1016/j.fct.2013.06.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 05/17/2013] [Accepted: 06/05/2013] [Indexed: 12/14/2022]
Abstract
The mouse lymphoma L5178Y Tk(+/-) assay is broadly used in toxicology to assess genotoxicity because of its known sensitivity to genotoxicants that act through a variety of mechanisms, which may include epigenetic DNA methylation. This brief article highlights the studies that have contributed to this conjecture and suggests an addition to the experimental design that could identify if the test substance is a potential epimutagen acting via hypermethylation.
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Affiliation(s)
- Tsu-Fan Cheng
- US Food and Drug Administration, Center for Food Safety and Applied Nutrition, Office of Food Additive Safety, Division of Food Contact Notification, College Park, MD 20740, USA
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