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Martin MM, Carpenter AF, Shafer TJ, Paul Friedman K, Carstens KE. Chemical effects on neural network activity: Comparison of acute versus network formation exposure in microelectrode array assays. Toxicology 2024; 505:153842. [PMID: 38788893 DOI: 10.1016/j.tox.2024.153842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 05/08/2024] [Accepted: 05/21/2024] [Indexed: 05/26/2024]
Abstract
New approach methodologies (NAMs) can address information gaps on potential neurotoxicity or developmental neurotoxicity hazard for data-poor chemicals. Two assays have been previously developed using microelectrode arrays (MEA), a technology which measures neural activity. The MEA acute network function assay (AcN) uses dissociated rat cortical cells cultured at postnatal day 0 and evaluates network activity during a 40-minute chemical exposure on day in vitro (DIV)13 or 15. In contrast, the MEA network formation assay (NFA) uses a developmental exposure paradigm spanning DIV0 through DIV12. Measures of network activity over time at DIV5, 7, 9, and 12 in the NFA are reduced to an estimated area under the curve to facilitate concentration-response evaluation. Here, we evaluated the hypothesis that chemicals with effects in the AcN also perturb the NFA by examining quantitative and qualitative concordance between assays. Out of 243 chemicals screened in both assays, we observed 70.3% concordance between the AcN and NFA after eliminating activity inferred to be cytotoxic (selective activity), with the majority of discordance explained by chemicals that altered selective activity in the AcN but not NFA. The NFA detected more active chemicals when evaluating activity associated with cytotoxicity. Median potency values were lower in the NFA compared to the AcN, but within-chemical potency values were not uniformly lower in the NFA than the AcN. Lastly, the AcN and NFA captured unique bioactivity fingerprints; the AcN was more informative for identifying chemicals with a shared mode of action, while the NFA provided information relevant to developmental exposure. Taken together, this analysis provides a rationale for using both approaches for chemical evaluation with consideration of the context of use, such as screening/ prioritization, hazard identification, or to address questions regarding biological mechanism or function.
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Affiliation(s)
- Melissa M Martin
- Computational Toxicology & Bioinformatics Branch, Biomolecular and Computational Toxicology Division, CCTE/ORD, US. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Amy F Carpenter
- Computational Toxicology & Bioinformatics Branch, Biomolecular and Computational Toxicology Division, CCTE/ORD, US. Environmental Protection Agency, Research Triangle Park, NC 27711, USA; Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, TN, USA
| | - Timothy J Shafer
- Computational Toxicology & Bioinformatics Branch, Biomolecular and Computational Toxicology Division, CCTE/ORD, US. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Katie Paul Friedman
- Computational Toxicology & Bioinformatics Branch, Biomolecular and Computational Toxicology Division, CCTE/ORD, US. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Kelly E Carstens
- Computational Toxicology & Bioinformatics Branch, Biomolecular and Computational Toxicology Division, CCTE/ORD, US. Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
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2
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Godderis L, De Ryck E, Baeyens W, Geerts L, Jacobs G, Maesen P, Mertens B, Schroyen G, Van Belleghem F, Vanoirbeek J, Van Larebeke N. Towards a more effective REACH legislation in protecting human health. Toxicol Sci 2024; 199:194-202. [PMID: 38419586 DOI: 10.1093/toxsci/kfae025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024] Open
Abstract
There is growing evidence indicating the substantial contribution of man-made products to an increase in the risk of diseases of civilization. In this article, the Belgian Scientific Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) Committee gives a critical view on the working of REACH. The current regulatory framework needs to further evolve taking into account data generated using modern science and technology. There is a need for improved assessment process not only before but also after entering the market. Objectivity, transparency, and the follow-up after market access can be optimized. Additionally, no guidance documents exist for regulation of mixture effects. Further, the lengthiness before regulatory action is a big concern. Decision-making often takes several years leading to uncertainties for both producers and end users. A first proposed improvement is the implementation of independent toxicity testing, to assure objectivity, transparency, and check and improve compliance. A "no data, no market" principle could prevent access of hazardous chemicals to the market. Additionally, the introduction of novel testing could improve information on endpoints such as endocrine disrupting abilities, neurotoxicity, and immunotoxicity. An adapted regulatory framework that integrates data from different sources and comparing the outputs with estimates of exposure is required. Fast toxicology battery testing and toxicokinetic testing could improve speed of decision-making. Hereby, several improvements have been proposed that could improve the current REACH legislation.
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Affiliation(s)
- Lode Godderis
- Department Public Health and Primary Care, Centre for Environment and Health, Catholic University Leuven, 3000 Leuven, Belgium
- External Service for Prevention and Protection at Work, IDEWE, 3001 Heverlee, Belgium
| | - Evi De Ryck
- Department Public Health and Primary Care, Centre for Environment and Health, Catholic University Leuven, 3000 Leuven, Belgium
| | - Willy Baeyens
- Analytical, Environmental and Geo-Chemistry, VUB, 1050 Brussels, Belgium
| | - Lieve Geerts
- Flemish Institute for Technological Research, VITO, 2400 Mol, Belgium
| | - Griet Jacobs
- Flemish Institute for Technological Research, VITO, 2400 Mol, Belgium
| | - Phillippe Maesen
- Faculté de Gembloux Agro-Bio Tech, Uliège, 5030 Gembloux, Belgium
| | - Birgit Mertens
- Department of Chemical and Physical Health Risks, Sciensano, 1050 Brussels, Belgium
| | - Guy Schroyen
- Institut Scientifique de Service Public, ISSeP, 4000 Liège, Belgium
| | - Frank Van Belleghem
- Department of Environmental Sciences, Faculty of Science, Open Universiteit, 6419 Heerlen, The Netherlands
- Zoology: Biodiversity and Toxicology, Centre for Environmental Sciences, Hasselt University, 3590 Diepenbeek, Belgium
| | - Jeroen Vanoirbeek
- Department Public Health and Primary Care, Centre for Environment and Health, Catholic University Leuven, 3000 Leuven, Belgium
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3
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Henriquez JE, Badwaik VD, Bianchi E, Chen W, Corvaro M, LaRocca J, Lunsman TD, Zu C, Johnson KJ. From Pipeline to Plant Protection Products: Using New Approach Methodologies (NAMs) in Agrochemical Safety Assessment. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:10710-10724. [PMID: 38688008 DOI: 10.1021/acs.jafc.4c00958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
The human population will be approximately 9.7 billion by 2050, and food security has been identified as one of the key issues facing the global population. Agrochemicals are an important tool available to farmers that enable high crop yields and continued access to healthy foods, but the average new agrochemical active ingredient takes more than ten years, 350 million dollars, and 20,000 animals to develop and register. The time, monetary, and animal costs incentivize the use of New Approach Methodologies (NAMs) in early-stage screening to prioritize chemical candidates. This review outlines NAMs that are currently available or can be adapted for use in early-stage screening agrochemical programs. It covers new in vitro screens that are on the horizon in key areas of regulatory concern. Overall, early-stage screening with NAMs enables the prioritization of development for agrochemicals without human and environmental health concerns through a more directed, agile, and iterative development program before animal-based regulatory testing is even considered.
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Affiliation(s)
| | - Vivek D Badwaik
- Corteva Agriscience, Indianapolis, Indiana 46268, United States
| | - Enrica Bianchi
- Corteva Agriscience, Indianapolis, Indiana 46268, United States
| | - Wei Chen
- Corteva Agriscience, Indianapolis, Indiana 46268, United States
| | | | - Jessica LaRocca
- Corteva Agriscience, Indianapolis, Indiana 46268, United States
| | | | - Chengli Zu
- Corteva Agriscience, Indianapolis, Indiana 46268, United States
| | - Kamin J Johnson
- Corteva Agriscience, Indianapolis, Indiana 46268, United States
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4
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Tal T, Myhre O, Fritsche E, Rüegg J, Craenen K, Aiello-Holden K, Agrillo C, Babin PJ, Escher BI, Dirven H, Hellsten K, Dolva K, Hessel E, Heusinkveld HJ, Hadzhiev Y, Hurem S, Jagiello K, Judzinska B, Klüver N, Knoll-Gellida A, Kühne BA, Leist M, Lislien M, Lyche JL, Müller F, Colbourne JK, Neuhaus W, Pallocca G, Seeger B, Scharkin I, Scholz S, Spjuth O, Torres-Ruiz M, Bartmann K. New approach methods to assess developmental and adult neurotoxicity for regulatory use: a PARC work package 5 project. FRONTIERS IN TOXICOLOGY 2024; 6:1359507. [PMID: 38742231 PMCID: PMC11089904 DOI: 10.3389/ftox.2024.1359507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 03/18/2024] [Indexed: 05/16/2024] Open
Abstract
In the European regulatory context, rodent in vivo studies are the predominant source of neurotoxicity information. Although they form a cornerstone of neurotoxicological assessments, they are costly and the topic of ethical debate. While the public expects chemicals and products to be safe for the developing and mature nervous systems, considerable numbers of chemicals in commerce have not, or only to a limited extent, been assessed for their potential to cause neurotoxicity. As such, there is a societal push toward the replacement of animal models with in vitro or alternative methods. New approach methods (NAMs) can contribute to the regulatory knowledge base, increase chemical safety, and modernize chemical hazard and risk assessment. Provided they reach an acceptable level of regulatory relevance and reliability, NAMs may be considered as replacements for specific in vivo studies. The European Partnership for the Assessment of Risks from Chemicals (PARC) addresses challenges to the development and implementation of NAMs in chemical risk assessment. In collaboration with regulatory agencies, Project 5.2.1e (Neurotoxicity) aims to develop and evaluate NAMs for developmental neurotoxicity (DNT) and adult neurotoxicity (ANT) and to understand the applicability domain of specific NAMs for the detection of endocrine disruption and epigenetic perturbation. To speed up assay time and reduce costs, we identify early indicators of later-onset effects. Ultimately, we will assemble second-generation developmental neurotoxicity and first-generation adult neurotoxicity test batteries, both of which aim to provide regulatory hazard and risk assessors and industry stakeholders with robust, speedy, lower-cost, and informative next-generation hazard and risk assessment tools.
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Affiliation(s)
- Tamara Tal
- Helmholtz Centre for Environmental Research – UFZ, Chemicals in the Environment Research Section, Leipzig, Germany
- University of Leipzig, Medical Faculty, Leipzig, Germany
| | - Oddvar Myhre
- Norwegian Institute of Public Health – NIPH, Department of Chemical Toxicology, Oslo, Norway
| | - Ellen Fritsche
- IUF – Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany
- DNTOX GmbH, Düsseldorf, Germany
- Swiss Centre for Applied Human Toxicology, University of Basel, Basel, Switzerland
| | - Joëlle Rüegg
- Uppsala University, Department of Organismal Biology, Uppsala, Sweden
| | - Kai Craenen
- European Chemicals Agency (ECHA), Helsinki, Finland
| | | | - Caroline Agrillo
- Uppsala University, Department of Organismal Biology, Uppsala, Sweden
| | - Patrick J. Babin
- Université de Bordeaux, Institut National de la Santé et de la Recherche Médicale (INSERM), Maladies Rares: Génétique et Métabolisme (MRGM), Pessac, France
| | - Beate I. Escher
- Helmholtz Centre for Environmental Research – UFZ, Chemicals in the Environment Research Section, Leipzig, Germany
| | - Hubert Dirven
- Norwegian Institute of Public Health – NIPH, Department of Chemical Toxicology, Oslo, Norway
| | | | - Kristine Dolva
- University of Oslo, Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, Olso, Norway
| | - Ellen Hessel
- Dutch Nation Institute for Public Health and the Environment (RIVM), Centre for Health Protection, Bilthoven, Netherlands
| | - Harm J. Heusinkveld
- Dutch Nation Institute for Public Health and the Environment (RIVM), Centre for Health Protection, Bilthoven, Netherlands
| | - Yavor Hadzhiev
- University of Birmingham, Centre for Environmental Research and Justice, Birmingham, UK
| | - Selma Hurem
- Norwegian University of Life Sciences (NMBU), Faculty of Veterinary Medicine, Ås, Norway
| | - Karolina Jagiello
- University of Gdansk, Laboratory of Environmental Chemoinformatics, Gdansk, Poland
| | - Beata Judzinska
- University of Gdansk, Laboratory of Environmental Chemoinformatics, Gdansk, Poland
| | - Nils Klüver
- Helmholtz Centre for Environmental Research – UFZ, Chemicals in the Environment Research Section, Leipzig, Germany
| | - Anja Knoll-Gellida
- Université de Bordeaux, Institut National de la Santé et de la Recherche Médicale (INSERM), Maladies Rares: Génétique et Métabolisme (MRGM), Pessac, France
| | - Britta A. Kühne
- University of Veterinary Medicine Hannover, Foundation, Institute for Food Quality and Food Safety, Hannover, Germany
| | - Marcel Leist
- University of Konstanz, In Vitro Toxicology and Biomedicine/CAAT-Europe, Konstanz, Germany
| | - Malene Lislien
- Norwegian Institute of Public Health – NIPH, Department of Chemical Toxicology, Oslo, Norway
| | - Jan L. Lyche
- Norwegian University of Life Sciences (NMBU), Faculty of Veterinary Medicine, Ås, Norway
| | - Ferenc Müller
- University of Birmingham, Centre for Environmental Research and Justice, Birmingham, UK
| | - John K. Colbourne
- University of Birmingham, Centre for Environmental Research and Justice, Birmingham, UK
| | - Winfried Neuhaus
- AIT Austrian Institute of Technology GmbH, Competence Unit Molecular Diagnostics, Center Health and Bioresources, Vienna, Austria
- Danube Private University, Faculty of Dentistry and Medicine, Department of Medicine, Krems, Austria
| | - Giorgia Pallocca
- University of Konstanz, In Vitro Toxicology and Biomedicine/CAAT-Europe, Konstanz, Germany
| | - Bettina Seeger
- University of Veterinary Medicine Hannover, Foundation, Institute for Food Quality and Food Safety, Hannover, Germany
| | - Ilka Scharkin
- IUF – Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany
| | - Stefan Scholz
- Helmholtz Centre for Environmental Research – UFZ, Chemicals in the Environment Research Section, Leipzig, Germany
| | - Ola Spjuth
- Uppsala University and Science for Life Laboratory, Department of Pharmaceutical Biosciences, Uppsala, Sweden
| | - Monica Torres-Ruiz
- Instituto de Salud Carlos III (ISCIII), Centro Nacional de Sanidad Ambiental (CNSA), Environmental Toxicology Unit, Majadahonda, Spain
| | - Kristina Bartmann
- IUF – Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany
- DNTOX GmbH, Düsseldorf, Germany
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5
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Ishibashi Y, Nagafuku N, Kanda Y, Suzuki I. Evaluation of neurotoxicity for pesticide-related compounds in human iPS cell-derived neurons using microelectrode array. Toxicol In Vitro 2023; 93:105668. [PMID: 37633473 DOI: 10.1016/j.tiv.2023.105668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 06/30/2023] [Accepted: 08/23/2023] [Indexed: 08/28/2023]
Abstract
In vivo evaluations of chemicals in neurotoxicity have certain limitations due to the considerable time and cost required, necessity of extrapolation from rodents to humans, and limited information on toxicity mechanisms. To address this issue, the development of in vitro test methods using new approach methodologies (NAMs) is important to evaluate the chemicals in neurotoxicity. Microelectrode array (MEA) allows the assessment of changes in neural network activity caused by compound administration. However, studies on compound evaluation criteria are scarce. In this study, we evaluated the impact of pesticides on neural activity using MEA measurements of human iPSC-derived neurons. A principal component analysis was performed on the electrical physiological parameters obtained by MEA measurements, and the influence of excessive neural activity due to compound addition was defined using the standard deviation of neural activity with solvent addition as the reference. By using known seizurogenic compounds as positive controls for neurotoxicity in MEA and evaluating pesticides with insufficient verification of their neurotoxicity in humans, we demonstrated that these pesticides exhibit neurotoxicity in humans. In conclusion, our data suggest that the neurotoxicity evaluation method in human iPSC neurons using MEA measurements could be one of the in vitro neurotoxicity test methods that could replace animal experiments.
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Affiliation(s)
- Yuto Ishibashi
- Department of Electronics, Graduate School of Engineering, Tohoku Institute of Technology, 35-1 Yagiyama Kasumicho, Taihaku-ku, Sendai, Miyagi 982-8577, Japan
| | - Nami Nagafuku
- Department of Electronics, Graduate School of Engineering, Tohoku Institute of Technology, 35-1 Yagiyama Kasumicho, Taihaku-ku, Sendai, Miyagi 982-8577, Japan
| | - Yasunari Kanda
- Division of Pharmacology, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-9501, Japan
| | - Ikuro Suzuki
- Department of Electronics, Graduate School of Engineering, Tohoku Institute of Technology, 35-1 Yagiyama Kasumicho, Taihaku-ku, Sendai, Miyagi 982-8577, Japan.
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6
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Kubickova B, Martinkova S, Bohaciakova D, Nezvedova M, Liu R, Brozman O, Spáčil Z, Hilscherova K. Effects of all-trans and 9-cis retinoic acid on differentiating human neural stem cells in vitro. Toxicology 2023; 487:153461. [PMID: 36805303 PMCID: PMC10019519 DOI: 10.1016/j.tox.2023.153461] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 02/02/2023] [Accepted: 02/14/2023] [Indexed: 02/17/2023]
Abstract
Cyanobacterial blooms are known sources of environmentally-occurring retinoid compounds, including all-trans and 9-cis retinoic acids (RAs). The developmental hazard for aquatic organisms has been described, while the implications for human health hazard assessment are not yet sufficiently characterized. Here, we employ a human neural stem cell model that can differentiate in vitro into a mixed culture of neurons and glia. Cells were exposed to non-cytotoxic 8-1000 nM all-trans or 9-cis RA for 9-18 days (DIV13 and DIV22, respectively). Impact on biomarkers was analyzed on gene expression (RT-qPCR) and protein level (western blot and proteomics) at both time points; network patterning (immunofluorescence) on DIV22. RA exposure significantly concentration-dependently increased gene expression of retinoic acid receptors and the metabolizing enzyme CYP26A1, confirming the chemical-specific response of the model. Expression of thyroid hormone signaling-related genes remained mostly unchanged. Markers of neural progenitors/stem cells (PAX6, SOX1, SOX2, NESTIN) were decreased with increasing RA concentrations, though a basal population remained. Neural markers (DCX, TUJ1, MAP2, NeuN, SYP) remained unchanged or were decreased at high concentrations (200-1000 nM). Conversely, (astro-)glial marker S100β was increased concentration-dependently on DIV22. Together, the biomarker analysis indicates an RA-dependent promotion of glial cell fates over neural differentiation, despite the increased abundance of neural protein biomarkers during differentiation. Interestingly, RA exposure induced substantial changes to the cell culture morphology: while low concentrations resulted in a network-like differentiation pattern, high concentrations (200-1000 nM RA) almost completely prevented such network patterning. After functional confirmation for implications in network function, such morphological features could present a proxy for network formation assessment, an apical key event in (neuro-)developmental Adverse Outcome Pathways. The described application of a human in vitro model for (developmental) neurotoxicity to emerging environmentally-relevant retinoids contributes to the evidence-base for the use of differentiating human in vitro models for human health hazard and risk assessment.
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Affiliation(s)
- Barbara Kubickova
- RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, Brno, Czech Republic.
| | - Sarka Martinkova
- RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, Brno, Czech Republic.
| | - Dasa Bohaciakova
- Masaryk University, Faculty of Medicine, Department of Histology and Embryology, Kamenice 3, 62500 Brno, Czech Republic.
| | - Marketa Nezvedova
- RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, Brno, Czech Republic.
| | - Runze Liu
- RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, Brno, Czech Republic.
| | - Ondrej Brozman
- RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, Brno, Czech Republic.
| | - Zdeněk Spáčil
- RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, Brno, Czech Republic.
| | - Klara Hilscherova
- RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, Brno, Czech Republic.
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7
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Pressman P, Clemens R, Hayes AW. Significant shifts in preclinical and clinical neurotoxicology: a review and commentary. Toxicol Mech Methods 2023; 33:173-182. [PMID: 35920262 DOI: 10.1080/15376516.2022.2109228] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
The ever-expanding prevalence of adverse neurotoxic reactions of the brain in response to therapeutic and recreational drugs, dietary supplements, environmental hazards, cosmetic ingredients, a spectrum of herbals, health status, and environmental stressors continues to prompt the development of novel cell-based assays to better determine neurotoxic hazard. Neurotoxicants may cause direct and epigenetic damage to the nervous tissue and alter the chemistry, structure, or normal activity of the nervous system. In severe neurotoxicity due to exposure to physical or psychosocial toxicants, neurons are disrupted or killed, and a consistent pattern of clinical neural dysfunction appears. In utero exposure to neurotoxicants can lead to altered development of the nervous system [developmental neurotoxicity (DNT)]. Patients with certain disorders and certain genomic makeup may be particularly susceptible to neurotoxicants. Traditional cytotoxicity measurements, like cell death, are easy to measure, but insufficient at identifying current routine biomarkers of toxicity including functional impairment in cell communication, which often occurs before or even in the absence of cell death. The present paper examines some of the limitations of existing neurotoxicology in light of the increasing need to develop tools to meet the challenges of achieving greater sensitivity in detection and developing and standardizing methods for exploring the toxicologic risk of such neurotoxic entities as engineered nanomaterials and even variables associated with poverty.
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Affiliation(s)
- Peter Pressman
- Clinical Medicine, Saba University School of Medicine, The Bottom, Caribbean, The Netherlands
| | - Roger Clemens
- School of Pharmacy, University of Southern California, Los Angeles, CA, USA
| | - A Wallace Hayes
- College of Public Health, University of South Florida, Tampa, FL, USA
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8
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Blum J, Masjosthusmann S, Bartmann K, Bendt F, Dolde X, Dönmez A, Förster N, Holzer AK, Hübenthal U, Keßel HE, Kilic S, Klose J, Pahl M, Stürzl LC, Mangas I, Terron A, Crofton KM, Scholze M, Mosig A, Leist M, Fritsche E. Establishment of a human cell-based in vitro battery to assess developmental neurotoxicity hazard of chemicals. CHEMOSPHERE 2023; 311:137035. [PMID: 36328314 DOI: 10.1016/j.chemosphere.2022.137035] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 10/20/2022] [Accepted: 10/24/2022] [Indexed: 06/16/2023]
Abstract
Developmental neurotoxicity (DNT) is a major safety concern for all chemicals of the human exposome. However, DNT data from animal studies are available for only a small percentage of manufactured compounds. Test methods with a higher throughput than current regulatory guideline methods, and with improved human relevance are urgently needed. We therefore explored the feasibility of DNT hazard assessment based on new approach methods (NAMs). An in vitro battery (IVB) was assembled from ten individual NAMs that had been developed during the past years to probe effects of chemicals on various fundamental neurodevelopmental processes. All assays used human neural cells at different developmental stages. This allowed us to assess disturbances of: (i) proliferation of neural progenitor cells (NPC); (ii) migration of neural crest cells, radial glia cells, neurons and oligodendrocytes; (iii) differentiation of NPC into neurons and oligodendrocytes; and (iv) neurite outgrowth of peripheral and central neurons. In parallel, cytotoxicity measures were obtained. The feasibility of concentration-dependent screening and of a reliable biostatistical processing of the complex multi-dimensional data was explored with a set of 120 test compounds, containing subsets of pre-defined positive and negative DNT compounds. The battery provided alerts (hit or borderline) for 24 of 28 known toxicants (82% sensitivity), and for none of the 17 negative controls. Based on the results from this screen project, strategies were developed on how IVB data may be used in the context of risk assessment scenarios employing integrated approaches for testing and assessment (IATA).
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Affiliation(s)
- Jonathan Blum
- In Vitro Toxicology and Biomedicine, Dept Inaugurated By the Doerenkamp-Zbinden Foundation, University of Konstanz, 78457, Konstanz, Germany.
| | - Stefan Masjosthusmann
- IUF - Leibniz Research Institute for Environmental Medicine, 40225, Düsseldorf, Germany
| | - Kristina Bartmann
- IUF - Leibniz Research Institute for Environmental Medicine, 40225, Düsseldorf, Germany
| | - Farina Bendt
- IUF - Leibniz Research Institute for Environmental Medicine, 40225, Düsseldorf, Germany
| | - Xenia Dolde
- In Vitro Toxicology and Biomedicine, Dept Inaugurated By the Doerenkamp-Zbinden Foundation, University of Konstanz, 78457, Konstanz, Germany
| | - Arif Dönmez
- IUF - Leibniz Research Institute for Environmental Medicine, 40225, Düsseldorf, Germany
| | - Nils Förster
- Bioinformatics Group, Ruhr University Bochum, 44801, Bochum, Germany
| | - Anna-Katharina Holzer
- In Vitro Toxicology and Biomedicine, Dept Inaugurated By the Doerenkamp-Zbinden Foundation, University of Konstanz, 78457, Konstanz, Germany
| | - Ulrike Hübenthal
- IUF - Leibniz Research Institute for Environmental Medicine, 40225, Düsseldorf, Germany
| | - Hagen Eike Keßel
- IUF - Leibniz Research Institute for Environmental Medicine, 40225, Düsseldorf, Germany
| | - Sadiye Kilic
- In Vitro Toxicology and Biomedicine, Dept Inaugurated By the Doerenkamp-Zbinden Foundation, University of Konstanz, 78457, Konstanz, Germany
| | - Jördis Klose
- IUF - Leibniz Research Institute for Environmental Medicine, 40225, Düsseldorf, Germany
| | - Melanie Pahl
- IUF - Leibniz Research Institute for Environmental Medicine, 40225, Düsseldorf, Germany
| | - Lynn-Christin Stürzl
- IUF - Leibniz Research Institute for Environmental Medicine, 40225, Düsseldorf, Germany
| | - Iris Mangas
- European Food Safety Authority, PREV Unit, 43126, Parma, Italy
| | - Andrea Terron
- European Food Safety Authority, PREV Unit, 43126, Parma, Italy
| | | | - Martin Scholze
- Institute of Environment Health and Societies, Brunel University London, UK
| | - Axel Mosig
- Bioinformatics Group, Ruhr University Bochum, 44801, Bochum, Germany
| | - Marcel Leist
- In Vitro Toxicology and Biomedicine, Dept Inaugurated By the Doerenkamp-Zbinden Foundation, University of Konstanz, 78457, Konstanz, Germany.
| | - Ellen Fritsche
- IUF - Leibniz Research Institute for Environmental Medicine, 40225, Düsseldorf, Germany; Medical Faculty, Heinrich-Heine-University, 40225, Düsseldorf, Germany.
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9
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de Leeuw VC, van Oostrom CTM, Wackers PFK, Pennings JLA, Hodemaekers HM, Piersma AH, Hessel EVS. Neuronal differentiation pathways and compound-induced developmental neurotoxicity in the human neural progenitor cell test (hNPT) revealed by RNA-seq. CHEMOSPHERE 2022; 304:135298. [PMID: 35700809 PMCID: PMC9247748 DOI: 10.1016/j.chemosphere.2022.135298] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 05/30/2022] [Accepted: 06/08/2022] [Indexed: 05/27/2023]
Abstract
There is an increased awareness that the use of animals for compound-induced developmental neurotoxicity (DNT) testing has limitations. Animal-free innovations, especially the ones based on human stem cell-based models are pivotal in studying DNT since they can mimic processes relevant to human brain development. Here we present the human neural progenitor test (hNPT), a 10-day protocol in which neural progenitor cells differentiate into a neuron-astrocyte co-culture. The study aimed to characterise differentiation over time and to find neurodevelopmental processes sensitive to compound exposure using transcriptomics. 3992 genes regulated in unexposed control cultures (p ≤ 0.001, log2FC ≥ 1) showed Gene Ontology (GO-) term enrichment for neuronal and glial differentiation, neurite extension, synaptogenesis, and synaptic transmission. Exposure to known or suspected DNT compounds (acrylamide, chlorpyrifos, fluoxetine, methyl mercury, or valproic acid) at concentrations resulting in 95% cell viability each regulated unique combinations of GO-terms relating to neural progenitor proliferation, neuronal and glial differentiation, axon development, synaptogenesis, synaptic transmission, and apoptosis. Investigation of the GO-terms 'neuron apoptotic process' and 'axon development' revealed common genes that were responsive across compounds, and might be used as biomarkers for DNT. The GO-term 'synaptic signalling', on the contrary, whilst also responsive to all compounds tested, showed little overlap in gene expression regulation patterns between the conditions. This GO-term may articulate compound-specific effects that may be relevant for revealing differences in mechanism of toxicity. Given its focus on neural progenitor cell to mature multilineage neuronal cell maturation and its detailed molecular readout based on gene expression analysis, hNPT might have added value as a tool for neurodevelopmental toxicity testing in vitro. Further assessment of DNT-specific biomarkers that represent these processes needs further studies.
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Affiliation(s)
- Victoria C de Leeuw
- Centre for Health Protection, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands; Institute for Risk Assessment Sciences (IRAS), Utrecht University, Utrecht, the Netherlands.
| | - Conny T M van Oostrom
- Centre for Health Protection, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
| | - Paul F K Wackers
- Centre for Health Protection, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
| | - Jeroen L A Pennings
- Centre for Health Protection, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
| | - Hennie M Hodemaekers
- Centre for Health Protection, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
| | - Aldert H Piersma
- Centre for Health Protection, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands; Institute for Risk Assessment Sciences (IRAS), Utrecht University, Utrecht, the Netherlands
| | - Ellen V S Hessel
- Centre for Health Protection, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
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10
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El-Masri H, Paul Friedman K, Isaacs K, Wetmore BA. Advances in computational methods along the exposure to toxicological response paradigm. Toxicol Appl Pharmacol 2022; 450:116141. [PMID: 35777528 PMCID: PMC9619339 DOI: 10.1016/j.taap.2022.116141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 05/27/2022] [Accepted: 06/23/2022] [Indexed: 10/17/2022]
Abstract
Human health risk assessment is a function of chemical toxicity, bioavailability to reach target biological tissues, and potential environmental exposure. These factors are complicated by many physiological, biochemical, physical and lifestyle factors. Furthermore, chemical health risk assessment is challenging in view of the large, and continually increasing, number of chemicals found in the environment. These challenges highlight the need to prioritize resources for the efficient and timely assessment of those environmental chemicals that pose greatest health risks. Computational methods, either predictive or investigative, are designed to assist in this prioritization in view of the lack of cost prohibitive in vivo experimental data. Computational methods provide specific and focused toxicity information using in vitro high throughput screening (HTS) assays. Information from the HTS assays can be converted to in vivo estimates of chemical levels in blood or target tissue, which in turn are converted to in vivo dose estimates that can be compared to exposure levels of the screened chemicals. This manuscript provides a review for the landscape of computational methods developed and used at the U.S. Environmental Protection Agency (EPA) highlighting their potentials and challenges.
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Affiliation(s)
- Hisham El-Masri
- Center for Computational Toxicology and Exposure, Office of Research and Development, U. S. Environmental Protection Agency, Research Triangle Park, NC, USA.
| | - Katie Paul Friedman
- Center for Computational Toxicology and Exposure, Office of Research and Development, U. S. Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Kristin Isaacs
- Center for Computational Toxicology and Exposure, Office of Research and Development, U. S. Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Barbara A Wetmore
- Center for Computational Toxicology and Exposure, Office of Research and Development, U. S. Environmental Protection Agency, Research Triangle Park, NC, USA
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11
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Stucki AO, Barton-Maclaren TS, Bhuller Y, Henriquez JE, Henry TR, Hirn C, Miller-Holt J, Nagy EG, Perron MM, Ratzlaff DE, Stedeford TJ, Clippinger AJ. Use of new approach methodologies (NAMs) to meet regulatory requirements for the assessment of industrial chemicals and pesticides for effects on human health. FRONTIERS IN TOXICOLOGY 2022; 4:964553. [PMID: 36119357 PMCID: PMC9475191 DOI: 10.3389/ftox.2022.964553] [Citation(s) in RCA: 64] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 07/28/2022] [Indexed: 11/13/2022] Open
Abstract
New approach methodologies (NAMs) are increasingly being used for regulatory decision making by agencies worldwide because of their potential to reliably and efficiently produce information that is fit for purpose while reducing animal use. This article summarizes the ability to use NAMs for the assessment of human health effects of industrial chemicals and pesticides within the United States, Canada, and European Union regulatory frameworks. While all regulations include some flexibility to allow for the use of NAMs, the implementation of this flexibility varies across product type and regulatory scheme. This article provides an overview of various agencies’ guidelines and strategic plans on the use of NAMs, and specific examples of the successful application of NAMs to meet regulatory requirements. It also summarizes intra- and inter-agency collaborations that strengthen scientific, regulatory, and public confidence in NAMs, thereby fostering their global use as reliable and relevant tools for toxicological evaluations. Ultimately, understanding the current regulatory landscape helps inform the scientific community on the steps needed to further advance timely uptake of approaches that best protect human health and the environment.
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Affiliation(s)
- Andreas O. Stucki
- PETA Science Consortium International e.V., Stuttgart, Germany
- *Correspondence: Andreas O. Stucki,
| | - Tara S. Barton-Maclaren
- Safe Environments Directorate, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, ON, Canada
| | - Yadvinder Bhuller
- Pest Management Regulatory Agency, Health Canada, Ottawa, ON, Canada
| | | | - Tala R. Henry
- Office of Pollution Prevention and Toxics, US Environmental Protection Agency, Washington, DC, United States
| | - Carole Hirn
- Scientific and Regulatory Affairs, JT International SA, Geneva, Switzerland
| | | | - Edith G. Nagy
- Bergeson & Campbell PC, Washington, DC, United States
| | - Monique M. Perron
- Office of Pesticide Programs, US Environmental Protection Agency, Washington, DC, United States
| | - Deborah E. Ratzlaff
- Safe Environments Directorate, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, ON, Canada
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12
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Martin MM, Baker NC, Boyes WK, Carstens KE, Culbreth ME, Gilbert ME, Harrill JA, Nyffeler J, Padilla S, Friedman KP, Shafer TJ. An expert-driven literature review of "negative" chemicals for developmental neurotoxicity (DNT) in vitro assay evaluation. Neurotoxicol Teratol 2022; 93:107117. [PMID: 35908584 DOI: 10.1016/j.ntt.2022.107117] [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: 01/04/2022] [Revised: 06/27/2022] [Accepted: 07/18/2022] [Indexed: 11/26/2022]
Abstract
To date, approximately 200 chemicals have been tested in US Environmental Protection Agency (EPA) or Organization for Economic Co-operation and Development (OECD) developmental neurotoxicity (DNT) guideline studies, leaving thousands of chemicals without traditional animal information on DNT hazard potential. To address this data gap, a battery of in vitro DNT new approach methodologies (NAMs) has been proposed. Evaluation of the performance of this battery will increase the confidence in its use to determine DNT chemical hazards. One approach to evaluate DNT NAM performance is to use a set of chemicals to evaluate sensitivity and specificity. Since a list of chemicals with potential evidence of in vivo DNT has been established, this study aims to develop a curated list of "negative" chemicals for inclusion in a "DNT NAM evaluation set". A workflow, including a literature search followed by an expert-driven literature review, was used to systematically screen 39 chemicals for lack of DNT effect. Expert panel members evaluated the scientific robustness of relevant studies to inform chemical categorizations. Following review, the panel discussed each chemical and made categorical determinations of "Favorable", "Not Favorable", or "Indeterminate" reflecting acceptance, lack of suitability, or uncertainty given specific limitations and considerations, respectively. The panel determined that 10, 22, and 7 chemicals met the criteria for "Favorable", "Not Favorable", and "Indeterminate", for use as negatives in a DNT NAM evaluation set. Ultimately, this approach not only supports DNT NAM performance evaluation but also highlights challenges in identifying large numbers of negative DNT chemicals.
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Affiliation(s)
- Melissa M Martin
- Rapid Assay Development Branch, Biomolecular and Computational Toxicology Division, CCTE/ORD, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Nancy C Baker
- Leidos, Research Triangle Park, Research Triangle Park, NC 27711, USA
| | - William K Boyes
- Neurological and Endocrine Toxicology Branch, Public Health and Integrated Toxicology Division, CPHEA/ORD, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Kelly E Carstens
- Rapid Assay Development Branch, Biomolecular and Computational Toxicology Division, CCTE/ORD, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Megan E Culbreth
- Rapid Assay Development Branch, Biomolecular and Computational Toxicology Division, CCTE/ORD, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Mary E Gilbert
- Neurological and Endocrine Toxicology Branch, Public Health and Integrated Toxicology Division, CPHEA/ORD, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Joshua A Harrill
- Rapid Assay Development Branch, Biomolecular and Computational Toxicology Division, CCTE/ORD, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Johanna Nyffeler
- Rapid Assay Development Branch, Biomolecular and Computational Toxicology Division, CCTE/ORD, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA; Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, TN, USA
| | - Stephanie Padilla
- Rapid Assay Development Branch, Biomolecular and Computational Toxicology Division, CCTE/ORD, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Katie Paul Friedman
- Computational Toxicology & Bioinformatics Branch, Biomolecular and Computational Toxicology Division, CCTE/ORD, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Timothy J Shafer
- Rapid Assay Development Branch, Biomolecular and Computational Toxicology Division, CCTE/ORD, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
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13
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A bioinformatics framework for targeted gene expression assay design: Application to in vitro developmental neurotoxicity screening in a rat model. Regul Toxicol Pharmacol 2022; 133:105211. [PMID: 35724854 DOI: 10.1016/j.yrtph.2022.105211] [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: 02/03/2022] [Revised: 05/05/2022] [Accepted: 06/13/2022] [Indexed: 11/23/2022]
Abstract
Brain development involves a series of intricately choreographed neuronal differentiation and maturation steps that are acutely vulnerable to interferences from chemical exposures. Many genes involved in neurodevelopmental processes show evolutionarily conserved expression patterns in mammals and may constitute useful indicators/biomarkers for the evaluation of potential developmental neurotoxicity. Based on these premises, this study developed a bioinformatics framework to guide the design of a gene expression-based in vitro developmental neurotoxicity assay targeting evolutionary conserved genes associated with neuronal differentiation and maturation in rat cerebellar granule cells (CGCs). Rat, mouse and human genes involved in neurodevelopment and presenting one-to-one orthology were selected and orthologous exons within these genes were identified. PCR primer sets were designed within these orthologous exons and their specificity was evaluated in silico. The performance and specificity of rat, mouse and human PCR primer sets were then confirmed experimentally. Finally, RT-qPCR analyses in CGCs exposed in vitro to well-known neurotoxicants (Chlorpyrifos and Chlorpyrifos oxon) uncovered perturbations of expression levels for most of the selected genes. This bioinformatics framework for gene and target sequence selection may facilitate the identification of transcriptional biomarkers for developmental neurotoxicity assays and the comparison of gene expression data across experimental models from different mammalian species.
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14
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Application of the adverse outcome pathway concept for investigating developmental neurotoxicity potential of Chinese herbal medicines by using human neural progenitor cells in vitro. Cell Biol Toxicol 2022; 39:319-343. [PMID: 35701726 PMCID: PMC10042984 DOI: 10.1007/s10565-022-09730-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 05/10/2022] [Indexed: 12/16/2022]
Abstract
Adverse outcome pathways (AOPs) are organized sequences of key events (KEs) that are triggered by a xenobiotic-induced molecular initiating event (MIE) and summit in an adverse outcome (AO) relevant to human or ecological health. The AOP framework causally connects toxicological mechanistic information with apical endpoints for application in regulatory sciences. AOPs are very useful to link endophenotypic, cellular endpoints in vitro to adverse health effects in vivo. In the field of in vitro developmental neurotoxicity (DNT), such cellular endpoints can be assessed using the human "Neurosphere Assay," which depicts different endophenotypes for a broad variety of neurodevelopmental KEs. Combining this model with large-scale transcriptomics, we evaluated DNT hazards of two selected Chinese herbal medicines (CHMs) Lei Gong Teng (LGT) and Tian Ma (TM), and provided further insight into their modes-of-action (MoA). LGT disrupted hNPC migration eliciting an exceptional migration endophenotype. Time-lapse microscopy and intervention studies indicated that LGT disturbs laminin-dependent cell adhesion. TM impaired oligodendrocyte differentiation in human but not rat NPCs and activated a gene expression network related to oxidative stress. The LGT results supported a previously published AOP on radial glia cell adhesion due to interference with integrin-laminin binding, while the results of TM exposure were incorporated into a novel putative, stressor-based AOP. This study demonstrates that the combination of phenotypic and transcriptomic analyses is a powerful tool to elucidate compounds' MoA and incorporate the results into novel or existing AOPs for a better perception of the DNT hazard in a regulatory context.
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15
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Labba NA, Wæhler HA, Houdaifi N, Zosen D, Haugen F, Paulsen RE, Hadera MG, Eskeland R. Paracetamol perturbs neuronal arborization and disrupts the cytoskeletal proteins SPTBN1 and TUBB3 in both human and chicken in vitro models. Toxicol Appl Pharmacol 2022; 449:116130. [PMID: 35714712 DOI: 10.1016/j.taap.2022.116130] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 05/28/2022] [Accepted: 06/10/2022] [Indexed: 11/26/2022]
Abstract
Epidemiological studies have linked long-term/high-dose usage of paracetamol (N-acetyl-para-aminophenol, APAP) during pregnancy to adverse neuropsychiatric outcomes, primarily attention-deficit hyperactive disorder (ADHD), in the offspring. Though variable, ADHD has been associated with phenotypic alterations characterized by reductions in grey matter densities and aberrations in structural connectivity, effects which are thought to originate in neurodevelopment. We used embryonic chicken cerebellar granule neurons (CGNs) and neuronally differentiating human NTERA2 cells (NT2Ns) to investigate the in vitro effects of APAP on cell viability, migration, neuritogenesis, and the intracellular levels of various proteins involved in neurodevelopment as well as in the maintenance of the structure and function of neurites. Exposure to APAP ranging from 100 to 1600 μM yielded concentration- and time-dependent reductions in cell viability and levels of neurite arborization, as well as reductions in the levels of the cytoskeletal protein β2-spectrin, with the highest APAP concentration resulting in between 50 and 75% reductions in the aforementioned metrics over the course of 72 h. Exposure to APAP also reduced migration in the NT2Ns but not CGNs. Moreover, we found concentration- and time-dependent increases in punctate aggregation of the cytoskeletal protein β3-tubulin following exposure to APAP in both cell model systems, with the highest APAP concentration approximately doubling the number of aggregates over 72-120 h. Our findings demonstrate that APAP negatively perturbs neurite arborization degree, with concurrent reductions in the protein levels of β2-spectrin and disruption of the integrity of β3-tubulin, both proteins of which play important roles in neuronal structure and function.
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Affiliation(s)
- Nils-Anders Labba
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, Faculty of Mathematics and Natural Sciences, University of Oslo, Norway; Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Norway; PharmaTox Strategic Research Initiative, Faculty of Mathematics and Natural Sciences, University of Oslo, Norway
| | - Hallvard Austin Wæhler
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Norway; PharmaTox Strategic Research Initiative, Faculty of Mathematics and Natural Sciences, University of Oslo, Norway
| | - Nora Houdaifi
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, Faculty of Mathematics and Natural Sciences, University of Oslo, Norway
| | - Denis Zosen
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, Faculty of Mathematics and Natural Sciences, University of Oslo, Norway
| | - Fred Haugen
- Department of Work Psychology and Physiology, National Institute of Occupational Health (STAMI), Oslo, Norway
| | - Ragnhild Elisabeth Paulsen
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, Faculty of Mathematics and Natural Sciences, University of Oslo, Norway; PharmaTox Strategic Research Initiative, Faculty of Mathematics and Natural Sciences, University of Oslo, Norway
| | - Mussie Ghezu Hadera
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, Faculty of Mathematics and Natural Sciences, University of Oslo, Norway; PharmaTox Strategic Research Initiative, Faculty of Mathematics and Natural Sciences, University of Oslo, Norway
| | - Ragnhild Eskeland
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Norway; PharmaTox Strategic Research Initiative, Faculty of Mathematics and Natural Sciences, University of Oslo, Norway.
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16
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Crofton KM, Bassan A, Behl M, Chushak YG, Fritsche E, Gearhart JM, Marty MS, Mumtaz M, Pavan M, Ruiz P, Sachana M, Selvam R, Shafer TJ, Stavitskaya L, Szabo DT, Szabo ST, Tice RR, Wilson D, Woolley D, Myatt GJ. Current status and future directions for a neurotoxicity hazard assessment framework that integrates in silico approaches. COMPUTATIONAL TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2022; 22:100223. [PMID: 35844258 PMCID: PMC9281386 DOI: 10.1016/j.comtox.2022.100223] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
Neurotoxicology is the study of adverse effects on the structure or function of the developing or mature adult nervous system following exposure to chemical, biological, or physical agents. The development of more informative alternative methods to assess developmental (DNT) and adult (NT) neurotoxicity induced by xenobiotics is critically needed. The use of such alternative methods including in silico approaches that predict DNT or NT from chemical structure (e.g., statistical-based and expert rule-based systems) is ideally based on a comprehensive understanding of the relevant biological mechanisms. This paper discusses known mechanisms alongside the current state of the art in DNT/NT testing. In silico approaches available today that support the assessment of neurotoxicity based on knowledge of chemical structure are reviewed, and a conceptual framework for the integration of in silico methods with experimental information is presented. Establishing this framework is essential for the development of protocols, namely standardized approaches, to ensure that assessments of NT and DNT based on chemical structures are generated in a transparent, consistent, and defendable manner.
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Affiliation(s)
| | - Arianna Bassan
- Innovatune srl, Via Giulio Zanon 130/D, 35129 Padova,
Italy
| | - Mamta Behl
- Division of the National Toxicology Program, National
Institutes of Environmental Health Sciences, Durham, NC 27709, USA
| | - Yaroslav G. Chushak
- Henry M Jackson Foundation for the Advancement of Military
Medicine, Wright-Patterson AFB, OH 45433, USA
| | - Ellen Fritsche
- IUF – Leibniz Research Institute for Environmental
Medicine & Medical Faculty Heinrich-Heine-University, Düsseldorf,
Germany
| | - Jeffery M. Gearhart
- Henry M Jackson Foundation for the Advancement of Military
Medicine, Wright-Patterson AFB, OH 45433, USA
| | | | - Moiz Mumtaz
- Agency for Toxic Substances and Disease Registry, US
Department of Health and Human Services, Atlanta, GA, USA
| | - Manuela Pavan
- Innovatune srl, Via Giulio Zanon 130/D, 35129 Padova,
Italy
| | - Patricia Ruiz
- Agency for Toxic Substances and Disease Registry, US
Department of Health and Human Services, Atlanta, GA, USA
| | - Magdalini Sachana
- Environment Health and Safety Division, Environment
Directorate, Organisation for Economic Co-Operation and Development (OECD), 75775
Paris Cedex 16, France
| | - Rajamani Selvam
- Office of Clinical Pharmacology, Office of Translational
Sciences, Center for Drug Evaluation and Research (CDER), U.S. Food and Drug
Administration (FDA), Silver Spring, MD 20993, USA
| | - Timothy J. Shafer
- Biomolecular and Computational Toxicology Division, Center
for Computational Toxicology and Exposure, US EPA, Research Triangle Park, NC,
USA
| | - Lidiya Stavitskaya
- Office of Clinical Pharmacology, Office of Translational
Sciences, Center for Drug Evaluation and Research (CDER), U.S. Food and Drug
Administration (FDA), Silver Spring, MD 20993, USA
| | | | | | | | - Dan Wilson
- The Dow Chemical Company, Midland, MI 48667, USA
| | | | - Glenn J. Myatt
- Instem, Columbus, OH 43215, USA
- Corresponding author.
(G.J. Myatt)
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17
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Dobreniecki S, Mendez E, Lowit A, Freudenrich TM, Wallace K, Carpenter A, Wetmore BA, Kreutz A, Korol-Bexell E, Friedman KP, Shafer TJ. Integration of toxicodynamic and toxicokinetic new approach methods into a weight-of-evidence analysis for pesticide developmental neurotoxicity assessment: A case-study with DL- and L-glufosinate. Regul Toxicol Pharmacol 2022; 131:105167. [PMID: 35413399 DOI: 10.1016/j.yrtph.2022.105167] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 02/14/2022] [Accepted: 04/06/2022] [Indexed: 01/13/2023]
Abstract
DL-glufosinate ammonium (DL-GLF) is a registered herbicide for which a guideline Developmental Neurotoxicity (DNT) study has been conducted. Offspring effects included altered brain morphometrics, decreased body weight, and increased motor activity. Guideline DNT studies are not available for its enriched isomers L-GLF acid and L-GLF ammonium; conducting one would be time consuming, resource-intensive, and possibly redundant given the existing DL-GLF DNT. To support deciding whether to request a guideline DNT study for the L-GLF isomers, DL-GLF and the L-GLF isomers were screened using in vitro assays for network formation and neurite outgrowth. DL-GLF and L-GLF isomers were without effects in both assays. DL-GLF and L-GLF (1-100 μM) isomers increased mean firing rate of mature networks to 120-140% of baseline. In vitro toxicokinetic assessments were used to derive administered equivalent doses (AEDs) for the in vitro testing concentrations. The AED for L-GLF was ∼3X higher than the NOAEL from the DL-GLF DNT indicating that the available guideline study would be protective of potential DNT due to L-GLF exposure. Based in part on the results of these in vitro studies, EPA is not requiring L-GLF isomer guideline DNT studies, thereby providing a case study for a useful application of DNT screening assays.
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Affiliation(s)
| | | | - Anna Lowit
- Office of Pesticide Programs USEPA, Washington, DC, USA
| | - Theresa M Freudenrich
- Center for Computational Toxicology and Exposure, Office of Research and Development. US Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Kathleen Wallace
- Center for Computational Toxicology and Exposure, Office of Research and Development. US Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Amy Carpenter
- Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, TN, USA
| | - Barbara A Wetmore
- Center for Computational Toxicology and Exposure, Office of Research and Development. US Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Anna Kreutz
- Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, TN, USA
| | | | - Katie Paul Friedman
- Center for Computational Toxicology and Exposure, Office of Research and Development. US Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Timothy J Shafer
- Center for Computational Toxicology and Exposure, Office of Research and Development. US Environmental Protection Agency, Research Triangle Park, NC, USA.
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18
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Nunes C, Gorczyca G, Mendoza-deGyves E, Ponti J, Bogni A, Carpi D, Bal-Price A, Pistollato F. Upscaling biological complexity to boost neuronal and oligodendroglia maturation and improve in vitro developmental neurotoxicity (DNT) evaluation. Reprod Toxicol 2022; 110:124-140. [PMID: 35378221 DOI: 10.1016/j.reprotox.2022.03.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 02/14/2022] [Accepted: 03/29/2022] [Indexed: 12/14/2022]
Abstract
Human induced pluripotent stem cell (iPSC)-derived neuronal and glial cell models are suitable to assess the effects of environmental chemicals on the developing brain. Such test systems can recapitulate several key neurodevelopmental features, such as neural stem cell formation and differentiation towards different neuronal subtypes and astrocytes, neurite outgrowth, synapse formation and neuronal network formation and function, which are crucial for brain development. While monolayer, two-dimensional (2D) cultures of human iPSC-neuronal or glial derivatives are generally suited for high-throughput testing, they also show some limitations. In particular, differentiation towards myelinating oligodendrocytes can only be achieved after extended periods in differentiation. In recent years, the implementation of three-dimensional (3D) neuronal and glial models obtained from human iPSCs has been shown to compensate for such limitations, enabling robust differentiation towards both neuronal and glial cell populations, myelination and formation of more mature neuronal network activity. Here we compared the differentiation capacity of human iPSC-derived neural stem cells cultured either as 2D monolayer or as 3D neurospheres, and assessed chlorpyrifos (CPF) effects. Data indicate that 3D neurospheres differentiate towards neurons and oligodendroglia more rapidly than 2D cultures; however, the 2D model is more suitable to assess neuronal functionality by analysis of spontaneous electrical activity using multielectrode array. Moreover, 2D and 3D test systems are diversely susceptible to CPF treatment. In conclusion, the selection of the most suitable in vitro test system (either 2D or 3D) should take into account the context of use and intended research goals ('fit for purpose' principle).
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Affiliation(s)
- Carolina Nunes
- Department of Biomedical Sciences, University of Lausanne, CH-1005 Lausanne, Switzerland
| | - Gabriela Gorczyca
- Department of Endocrinology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University in Krakow, Kraków, Poland
| | | | - Jessica Ponti
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | - Alessia Bogni
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | - Donatella Carpi
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | - Anna Bal-Price
- European Commission, Joint Research Centre (JRC), Ispra, Italy
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19
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Koch K, Bartmann K, Hartmann J, Kapr J, Klose J, Kuchovská E, Pahl M, Schlüppmann K, Zühr E, Fritsche E. Scientific Validation of Human Neurosphere Assays for Developmental Neurotoxicity Evaluation. FRONTIERS IN TOXICOLOGY 2022; 4:816370. [PMID: 35295221 PMCID: PMC8915868 DOI: 10.3389/ftox.2022.816370] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 01/21/2022] [Indexed: 01/06/2023] Open
Abstract
There is a call for a paradigm shift in developmental neurotoxicity (DNT) evaluation, which demands the implementation of faster, more cost-efficient, and human-relevant test systems than current in vivo guideline studies. Under the umbrella of the Organisation for Economic Co-operation and Development (OECD), a guidance document is currently being prepared that instructs on the regulatory use of a DNT in vitro battery (DNT IVB) for fit-for-purpose applications. One crucial issue for OECD application of methods is validation, which for new approach methods (NAMs) requires novel approaches. Here, mechanistic information previously identified in vivo, as well as reported neurodevelopmental adversities in response to disturbances on the cellular and tissue level, are of central importance. In this study, we scientifically validate the Neurosphere Assay, which is based on human primary neural progenitor cells (hNPCs) and an integral part of the DNT IVB. It assesses neurodevelopmental key events (KEs) like NPC proliferation (NPC1ab), radial glia cell migration (NPC2a), neuronal differentiation (NPC3), neurite outgrowth (NPC4), oligodendrocyte differentiation (NPC5), and thyroid hormone-dependent oligodendrocyte maturation (NPC6). In addition, we extend our work from the hNPCs to human induced pluripotent stem cell-derived NPCs (hiNPCs) for the NPC proliferation (iNPC1ab) and radial glia assays (iNPC2a). The validation process we report for the endpoints studied with the Neurosphere Assays is based on 1) describing the relevance of the respective endpoints for brain development, 2) the confirmation of the cell type-specific morphologies observed in vitro, 3) expressions of cell type-specific markers consistent with those morphologies, 4) appropriate anticipated responses to physiological pertinent signaling stimuli and 5) alterations in specific in vitro endpoints upon challenges with confirmed DNT compounds. With these strong mechanistic underpinnings, we posit that the Neurosphere Assay as an integral part of the DNT in vitro screening battery is well poised for DNT evaluation for regulatory purposes.
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Affiliation(s)
- Katharina Koch
- IUF—Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Kristina Bartmann
- IUF—Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Julia Hartmann
- IUF—Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Julia Kapr
- IUF—Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Jördis Klose
- IUF—Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Eliška Kuchovská
- IUF—Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Melanie Pahl
- IUF—Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Kevin Schlüppmann
- IUF—Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Etta Zühr
- IUF—Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Ellen Fritsche
- IUF—Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
- Medical Faculty, Heinrich-Heine-University, Duesseldorf, Germany
- *Correspondence: Ellen Fritsche,
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20
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Cediel-Ulloa A, Lupu DL, Johansson Y, Hinojosa M, Özel F, Rüegg J. Impact of endocrine disrupting chemicals on neurodevelopment: the need for better testing strategies for endocrine disruption-induced developmental neurotoxicity. Expert Rev Endocrinol Metab 2022; 17:131-141. [PMID: 35255767 DOI: 10.1080/17446651.2022.2044788] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 02/17/2022] [Indexed: 10/19/2022]
Abstract
INTRODUCTION Brain development is highly dependent on hormonal regulation. Exposure to chemicals disrupting endocrine signaling has been associated with neurodevelopmental impairment. This raises concern about exposure to the suspected thousands of endocrine disruptors, and has resulted in efforts to improve regulation of these chemicals. Yet, the causal links between endocrine disruption and developmental neurotoxicity, which would be required for regulatory action, are still largely missing. AREAS COVERED In this review, we illustrate the importance of two endocrine systems, thyroid hormone and retinoic acid pathways, for neurodevelopment. We place special emphasis on TH and RA synthesis, metabolism, and how endocrine disrupting chemicals known or suspected to affect these systems are associated with developmental neurotoxicity. EXPERT OPINION While it is clear that neurodevelopment is dependent on proper hormonal functioning, and evidence is increasing for developmental neurotoxicity induced by endocrine disrupting chemicals, this is not grasped by current chemical testing. Thus, there is an urgent need to develop test methods detecting endocrine disruption in the context of neurodevelopment. Key to this development is further mechanistic insights on the involvement of endocrine signaling in neurodevelopment as well as increased support to develop and validate new test methods for the regulatory context.
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Affiliation(s)
| | | | - Ylva Johansson
- Department of Biochemistry and Biophysics, Stockholm University, Sweden
| | - Maria Hinojosa
- Department of Biochemistry and Biophysics, Stockholm University, Sweden
| | - Fatih Özel
- Department of Organismal Biology, Uppsala University, Sweden
- Centre for Women's Mental Health during the Reproductive Lifespan - Womher, Uppsala University, Sweden
- Department of Health Sciences, Karlstad University, Karlstad, Sweden
| | - Joëlle Rüegg
- Department of Organismal Biology, Uppsala University, Sweden
- Department of Health Sciences, Karlstad University, Karlstad, Sweden
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21
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Culbreth M, Nyffeler J, Willis C, Harrill JA. Optimization of Human Neural Progenitor Cells for an Imaging-Based High-Throughput Phenotypic Profiling Assay for Developmental Neurotoxicity Screening. FRONTIERS IN TOXICOLOGY 2022; 3:803987. [PMID: 35295155 PMCID: PMC8915842 DOI: 10.3389/ftox.2021.803987] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 12/27/2021] [Indexed: 11/13/2022] Open
Abstract
Studies in in vivo rodent models have been the accepted approach by regulatory agencies to evaluate potential developmental neurotoxicity (DNT) of chemicals for decades. These studies, however, are inefficient and cannot meet the demand for the thousands of chemicals that need to be assessed for DNT hazard. As such, several in vitro new approach methods (NAMs) have been developed to circumvent limitations of these traditional studies. The DNT NAMs, some of which utilize human-derived cell models, are intended to be employed in a testing battery approach, each focused on a specific neurodevelopmental process. The need for multiple assays, however, to evaluate each process can prolong testing and prioritization of chemicals for more in depth assessments. Therefore, a multi-endpoint higher-throughput approach to assess DNT hazard potential would be of value. Accordingly, we have adapted a high-throughput phenotypic profiling (HTPP) approach for use with human-derived neural progenitor (hNP1) cells. HTPP is a fluorescence-based assay that quantitatively measures alterations in cellular morphology. This approach, however, required optimization of several laboratory procedures prior to chemical screening. First, we had to determine an appropriate cell plating density in 384-well plates. We then had to identify the minimum laminin concentration required for optimal cell growth and attachment. And finally, we had to evaluate whether addition of antibiotics to the culture medium would alter cellular morphology. We selected 6,000 cells/well as an appropriate plating density, 20 µg/ml laminin for optimal cell growth and attachment, and antibiotic addition in the culture medium. After optimizing hNP1 cell culture conditions for HTPP, it was then necessary to select appropriate in-plate assay controls from a reference chemical set. These reference chemicals were previously demonstrated to elicit unique phenotypic profiles in various other cell types. Aphidicolin, bafilomycin A1, berberine chloride, and cucurbitacin I induced robust phenotypic profiles as compared to dimethyl sulfoxide vehicle control in the hNP1 cells, and thus can be employed as in-plate assay controls for subsequent chemical screens. We have optimized HTPP for hNP1 cells, and consequently this approach can now be assessed as a potential NAM for DNT hazard evaluation and results compared to previously developed DNT assays.
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Affiliation(s)
- Megan Culbreth
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Durham, NC, United States
| | - Johanna Nyffeler
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Durham, NC, United States
- Oak Ridge Institute for Science and Education (ORISE) Postdoctoral Fellow, Oak Ridge, TN, United States
| | - Clinton Willis
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Durham, NC, United States
| | - Joshua A. Harrill
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Durham, NC, United States
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22
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Spînu N, Cronin MT, Lao J, Bal-Price A, Campia I, Enoch SJ, Madden JC, Mora Lagares L, Novič M, Pamies D, Scholz S, Villeneuve DL, Worth AP. Probabilistic modelling of developmental neurotoxicity based on a simplified adverse outcome pathway network. COMPUTATIONAL TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2022; 21:100206. [PMID: 35211661 PMCID: PMC8857173 DOI: 10.1016/j.comtox.2021.100206] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 11/08/2021] [Accepted: 11/25/2021] [Indexed: 12/14/2022]
Abstract
In a century where toxicology and chemical risk assessment are embracing alternative methods to animal testing, there is an opportunity to understand the causal factors of neurodevelopmental disorders such as learning and memory disabilities in children, as a foundation to predict adverse effects. New testing paradigms, along with the advances in probabilistic modelling, can help with the formulation of mechanistically-driven hypotheses on how exposure to environmental chemicals could potentially lead to developmental neurotoxicity (DNT). This investigation aimed to develop a Bayesian hierarchical model of a simplified AOP network for DNT. The model predicted the probability that a compound induces each of three selected common key events (CKEs) of the simplified AOP network and the adverse outcome (AO) of DNT, taking into account correlations and causal relations informed by the key event relationships (KERs). A dataset of 88 compounds representing pharmaceuticals, industrial chemicals and pesticides was compiled including physicochemical properties as well as in silico and in vitro information. The Bayesian model was able to predict DNT potential with an accuracy of 76%, classifying the compounds into low, medium or high probability classes. The modelling workflow achieved three further goals: it dealt with missing values; accommodated unbalanced and correlated data; and followed the structure of a directed acyclic graph (DAG) to simulate the simplified AOP network. Overall, the model demonstrated the utility of Bayesian hierarchical modelling for the development of quantitative AOP (qAOP) models and for informing the use of new approach methodologies (NAMs) in chemical risk assessment.
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Key Words
- ADMET, Absorption, distribution, metabolism, excretion, and toxicity
- AO, Adverse outcome
- AOP, Adverse outcome pathway
- Adverse Outcome Pathway
- BBB, Blood-brain-barrier
- BDNF, Brain-derived neurotrophic factor
- Bayesian hierarchical model
- CAS RN, Chemical Abstracts Service Registry Number
- CI, Credible interval CKE, Common key event
- CNS, Central nervous system
- CRA, Chemical risk assessment
- Common Key Event
- DAG, Directed acyclic graph
- DNT, Developmental neurotoxicity
- DTXSID, The US EPA Comptox Chemical Dashboard substance identifier
- Developmental Neurotoxicity
- EC, Effective concentration
- HDI, Highest density interval
- IATA, Integrated Approaches to Testing and Assessment
- KE, Key event
- KER, Key event relationship
- LDH, Lactate dehydrogenase
- MCMC, Markov chain Monte Carlo
- MIE, Molecular initiating event
- NAM, New approach methodology
- New Approach Methodology
- OECD, Organisation for Economic Cooperation and Development
- P-gp, P-glycoprotein
- PBK, Physiologically-based kinetic
- QSAR, Quantitative structure-activity relationship
- SMILES, Simplified molecular input line entry system
- qAOP, Quantitative adverse outcome pathway
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Affiliation(s)
- Nicoleta Spînu
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK
| | - Mark T.D. Cronin
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK
| | - Junpeng Lao
- Department of Psychology, University of Fribourg, Fribourg CH-1700, Switzerland
| | - Anna Bal-Price
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | - Ivana Campia
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | - Steven J. Enoch
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK
| | - Judith C. Madden
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK
| | - Liadys Mora Lagares
- Jožef Stefan International Postgraduate School, 1000 Ljubljana, Slovenia
- Theory Department, Laboratory for Cheminformatics, National Institute of Chemistry, 1000 Ljubljana, Slovenia
| | - Marjana Novič
- Theory Department, Laboratory for Cheminformatics, National Institute of Chemistry, 1000 Ljubljana, Slovenia
| | - David Pamies
- Department of Biomedical Science, University of Lausanne, Lausanne, Vaud, Switzerland
- Swiss Centre for Applied Human Toxicology (SCAHT), Switzerland
| | - Stefan Scholz
- Helmholtz-Centre for Environmental Research − UFZ, Department of Bioanalytical Ecotoxicology, Permoserstrasse 15, 04318 Leipzig, Germany
| | - Daniel L. Villeneuve
- US Environmental Protection Agency, Great Lakes Toxicology and Ecology Division, Duluth, MN 55804, MN, USA
| | - Andrew P. Worth
- European Commission, Joint Research Centre (JRC), Ispra, Italy
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23
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Carstens KE, Carpenter AF, Martin MM, Harrill JA, Shafer TJ, Paul Friedman K. OUP accepted manuscript. Toxicol Sci 2022; 187:62-79. [PMID: 35172012 PMCID: PMC9421662 DOI: 10.1093/toxsci/kfac018] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In vivo developmental neurotoxicity (DNT) testing is resource intensive and lacks information on cellular processes affected by chemicals. To address this, DNT new approach methodologies (NAMs) are being evaluated, including: the microelectrode array neuronal network formation assay; and high-content imaging to evaluate proliferation, apoptosis, neurite outgrowth, and synaptogenesis. This work addresses 3 hypotheses: (1) a broad screening battery provides a sensitive marker of DNT bioactivity; (2) selective bioactivity (occurring at noncytotoxic concentrations) may indicate functional processes disrupted; and, (3) a subset of endpoints may optimally classify chemicals with in vivo evidence for DNT. The dataset was comprised of 92 chemicals screened in all 57 assay endpoints sourced from publicly available data, including a set of DNT NAM evaluation chemicals with putative positives (53) and negatives (13). The DNT NAM battery provides a sensitive marker of DNT bioactivity, particularly in cytotoxicity and network connectivity parameters. Hierarchical clustering suggested potency (including cytotoxicity) was important for classifying positive chemicals with high sensitivity (93%) but failed to distinguish patterns of disrupted functional processes. In contrast, clustering of selective values revealed informative patterns of differential activity but demonstrated lower sensitivity (74%). The false negatives were associated with several limitations, such as the maximal concentration tested or gaps in the biology captured by the current battery. This work demonstrates that this multi-dimensional assay suite provides a sensitive biomarker for DNT bioactivity, with selective activity providing possible insight into specific functional processes affected by chemical exposure and a basis for further research.
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Affiliation(s)
- Kelly E Carstens
- Center for Computational Toxicology and Exposure, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711, USA
- Oak Ridge Associated Universities, Oak Ridge, Tennessee 37830, USA
| | - Amy F Carpenter
- Center for Computational Toxicology and Exposure, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711, USA
- Oak Ridge Associated Universities, Oak Ridge, Tennessee 37830, USA
| | - Melissa M Martin
- Center for Computational Toxicology and Exposure, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711, USA
| | - Joshua A Harrill
- Center for Computational Toxicology and Exposure, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711, USA
| | - Timothy J Shafer
- Center for Computational Toxicology and Exposure, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711, USA
| | - Katie Paul Friedman
- Center for Computational Toxicology and Exposure, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711, USA
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24
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Förster N, Butke J, Keßel HE, Bendt F, Pahl M, Li L, Fan X, Leung PC, Klose J, Masjosthusmann S, Fritsche E, Mosig A. Reliable identification and quantification of neural cells in microscopic images of neurospheres. Cytometry A 2021; 101:411-422. [PMID: 34747115 DOI: 10.1002/cyto.a.24514] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 09/28/2021] [Accepted: 10/28/2021] [Indexed: 12/30/2022]
Abstract
Neurosphere cultures consisting of primary human neural stem/progenitor cells (hNPC) are used for studying the effects of substances on early neurodevelopmental processes in vitro. Differentiating hNPCs migrate and differentiate into radial glia, neurons, astrocytes, and oligodendrocytes upon plating on a suitable extracellular matrix and thus model processes of early neural development. In order to characterize alterations in hNPC development, it is thus an essential task to reliably identify the cell type of each migrated cell in the migration area of a neurosphere. To this end, we introduce and validate a deep learning approach for identifying and quantifying cell types in microscopic images of differentiated hNPC. As we demonstrate, our approach performs with high accuracy and is robust against typical potential confounders. We demonstrate that our deep learning approach reproduces the dose responses of well-established developmental neurotoxic compounds and controls, indicating its potential in medium or high throughput in vitro screening studies. Hence, our approach can be used for studying compound effects on neural differentiation processes in an automated and unbiased process.
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Affiliation(s)
- Nils Förster
- Department of Bioinformatics, Center for Protein Diagnostics, Ruhr-University Bochum, Gesundheitscampus 4, Bochum, Germany
| | - Joshua Butke
- Bioinformatics, Faculty of Biology and Biotechnology, Ruhr-University Bochum, Universitätsstr 150, Bochum, Germany
| | - Hagen Eike Keßel
- IUF - Leibniz Research Institute for Environmental Medicine, Düsseldorf, North Rhine-Westphalia, Germany
| | - Farina Bendt
- IUF - Leibniz Research Institute for Environmental Medicine, Düsseldorf, North Rhine-Westphalia, Germany
| | - Melanie Pahl
- IUF - Leibniz Research Institute for Environmental Medicine, Düsseldorf, North Rhine-Westphalia, Germany
| | - Lu Li
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
- Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Shatin New Town, Hong Kong
- Institute of Chinese Medicine, The Chinese University of Hong Kong, Shatin New Town, Hong Kong
| | - Xiaohui Fan
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Ping-Chung Leung
- Institute of Chinese Medicine, The Chinese University of Hong Kong, Shatin New Town, Hong Kong
| | - Jördis Klose
- IUF - Leibniz Research Institute for Environmental Medicine, Düsseldorf, North Rhine-Westphalia, Germany
| | - Stefan Masjosthusmann
- IUF - Leibniz Research Institute for Environmental Medicine, Düsseldorf, North Rhine-Westphalia, Germany
| | - Ellen Fritsche
- IUF - Leibniz Research Institute for Environmental Medicine, Düsseldorf, North Rhine-Westphalia, Germany
| | - Axel Mosig
- Department of Bioinformatics, Center for Protein Diagnostics, Ruhr-University Bochum, Gesundheitscampus 4, Bochum, Germany
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25
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Arnesdotter E, Rogiers V, Vanhaecke T, Vinken M. An overview of current practices for regulatory risk assessment with lessons learnt from cosmetics in the European Union. Crit Rev Toxicol 2021; 51:395-417. [PMID: 34352182 DOI: 10.1080/10408444.2021.1931027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Risk assessments of various types of chemical compounds are carried out in the European Union (EU) foremost to comply with legislation and to support regulatory decision-making with respect to their safety. Historically, risk assessment has relied heavily on animal experiments. However, the EU is committed to reduce animal experimentation and has implemented several legislative changes, which have triggered a paradigm shift towards human-relevant animal-free testing in the field of toxicology, in particular for risk assessment. For some specific endpoints, such as skin corrosion and irritation, validated alternatives are available whilst for other endpoints, including repeated dose systemic toxicity, the use of animal data is still central to meet the information requirements stipulated in the different legislations. The present review aims to provide an overview of established and more recently introduced methods for hazard assessment and risk characterisation for human health, in particular in the context of the EU Cosmetics Regulation (EC No 1223/2009) as well as the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) Regulation (EC 1907/2006).
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Affiliation(s)
- Emma Arnesdotter
- Department of Pharmaceutical and Pharmacological Sciences, Research Group of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel, Brussels, Belgium
| | - Vera Rogiers
- Department of Pharmaceutical and Pharmacological Sciences, Research Group of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel, Brussels, Belgium
| | - Tamara Vanhaecke
- Department of Pharmaceutical and Pharmacological Sciences, Research Group of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel, Brussels, Belgium
| | - Mathieu Vinken
- Department of Pharmaceutical and Pharmacological Sciences, Research Group of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel, Brussels, Belgium
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26
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Hernández‐Jerez A, Adriaanse P, Aldrich A, Berny P, Coja T, Duquesne S, Focks A, Marinovich M, Millet M, Pelkonen O, Pieper S, Tiktak A, Topping C, Widenfalk A, Wilks M, Wolterink G, Crofton K, Hougaard Bennekou S, Paparella M, Tzoulaki I. Development of Integrated Approaches to Testing and Assessment (IATA) case studies on developmental neurotoxicity (DNT) risk assessment. EFSA J 2021. [DOI: 10.2903/j.efsa.2021.6599] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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27
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Pistollato F, Madia F, Corvi R, Munn S, Grignard E, Paini A, Worth A, Bal-Price A, Prieto P, Casati S, Berggren E, Bopp SK, Zuang V. Current EU regulatory requirements for the assessment of chemicals and cosmetic products: challenges and opportunities for introducing new approach methodologies. Arch Toxicol 2021; 95:1867-1897. [PMID: 33851225 PMCID: PMC8166712 DOI: 10.1007/s00204-021-03034-y] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 03/18/2021] [Indexed: 12/28/2022]
Abstract
The EU Directive 2010/63/EU on the protection of animals used for scientific purposes and other EU regulations, such as REACH and the Cosmetic Products Regulation advocate for a change in the way toxicity testing is conducted. Whilst the Cosmetic Products Regulation bans animal testing altogether, REACH aims for a progressive shift from in vivo testing towards quantitative in vitro and computational approaches. Several endpoints can already be addressed using non-animal approaches including skin corrosion and irritation, serious eye damage and irritation, skin sensitisation, and mutagenicity and genotoxicity. However, for systemic effects such as acute toxicity, repeated dose toxicity and reproductive and developmental toxicity, evaluation of chemicals under REACH still heavily relies on animal tests. Here we summarise current EU regulatory requirements for the human health assessment of chemicals under REACH and the Cosmetic Products Regulation, considering the more critical endpoints and identifying the main challenges in introducing alternative methods into regulatory testing practice. This supports a recent initiative taken by the International Cooperation on Alternative Test Methods (ICATM) to summarise current regulatory requirements specific for the assessment of chemicals and cosmetic products for several human health-related endpoints, with the aim of comparing different jurisdictions and coordinating the promotion and ultimately the implementation of non-animal approaches worldwide. Recent initiatives undertaken at European level to promote the 3Rs and the use of alternative methods in current regulatory practice are also discussed.
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Affiliation(s)
- Francesca Pistollato
- Directorate F-Health, Consumers and Reference Materials, Unit F3 Chemicals Safety and Alternative Methods, European Commission, Joint Research Centre (JRC), Via E. Fermi, 2749. TP126, 21027, Ispra, VA, Italy
| | - Federica Madia
- Directorate F-Health, Consumers and Reference Materials, Unit F3 Chemicals Safety and Alternative Methods, European Commission, Joint Research Centre (JRC), Via E. Fermi, 2749. TP126, 21027, Ispra, VA, Italy
| | - Raffaella Corvi
- Directorate F-Health, Consumers and Reference Materials, Unit F3 Chemicals Safety and Alternative Methods, European Commission, Joint Research Centre (JRC), Via E. Fermi, 2749. TP126, 21027, Ispra, VA, Italy
| | - Sharon Munn
- Directorate F-Health, Consumers and Reference Materials, Unit F3 Chemicals Safety and Alternative Methods, European Commission, Joint Research Centre (JRC), Via E. Fermi, 2749. TP126, 21027, Ispra, VA, Italy
| | - Elise Grignard
- Directorate F-Health, Consumers and Reference Materials, Unit F3 Chemicals Safety and Alternative Methods, European Commission, Joint Research Centre (JRC), Via E. Fermi, 2749. TP126, 21027, Ispra, VA, Italy
| | - Alicia Paini
- Directorate F-Health, Consumers and Reference Materials, Unit F3 Chemicals Safety and Alternative Methods, European Commission, Joint Research Centre (JRC), Via E. Fermi, 2749. TP126, 21027, Ispra, VA, Italy
| | - Andrew Worth
- Directorate F-Health, Consumers and Reference Materials, Unit F3 Chemicals Safety and Alternative Methods, European Commission, Joint Research Centre (JRC), Via E. Fermi, 2749. TP126, 21027, Ispra, VA, Italy
| | - Anna Bal-Price
- Directorate F-Health, Consumers and Reference Materials, Unit F3 Chemicals Safety and Alternative Methods, European Commission, Joint Research Centre (JRC), Via E. Fermi, 2749. TP126, 21027, Ispra, VA, Italy
| | - Pilar Prieto
- Directorate F-Health, Consumers and Reference Materials, Unit F3 Chemicals Safety and Alternative Methods, European Commission, Joint Research Centre (JRC), Via E. Fermi, 2749. TP126, 21027, Ispra, VA, Italy
| | - Silvia Casati
- Directorate F-Health, Consumers and Reference Materials, Unit F3 Chemicals Safety and Alternative Methods, European Commission, Joint Research Centre (JRC), Via E. Fermi, 2749. TP126, 21027, Ispra, VA, Italy
| | - Elisabet Berggren
- Directorate F-Health, Consumers and Reference Materials, Unit F3 Chemicals Safety and Alternative Methods, European Commission, Joint Research Centre (JRC), Via E. Fermi, 2749. TP126, 21027, Ispra, VA, Italy
| | - Stephanie K Bopp
- Directorate F-Health, Consumers and Reference Materials, Unit F3 Chemicals Safety and Alternative Methods, European Commission, Joint Research Centre (JRC), Via E. Fermi, 2749. TP126, 21027, Ispra, VA, Italy
| | - Valérie Zuang
- Directorate F-Health, Consumers and Reference Materials, Unit F3 Chemicals Safety and Alternative Methods, European Commission, Joint Research Centre (JRC), Via E. Fermi, 2749. TP126, 21027, Ispra, VA, Italy.
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28
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Neurodevelopmental toxicity assessment of flame retardants using a human DNT in vitro testing battery. Cell Biol Toxicol 2021; 38:781-807. [PMID: 33969458 PMCID: PMC9525352 DOI: 10.1007/s10565-021-09603-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 03/11/2021] [Indexed: 12/12/2022]
Abstract
Due to their neurodevelopmental toxicity, flame retardants (FRs) like polybrominated diphenyl ethers are banned from the market and replaced by alternative FRs, like organophosphorus FRs, that have mostly unknown toxicological profiles. To study their neurodevelopmental toxicity, we evaluated the hazard of several FRs including phased-out polybrominated FRs and organophosphorus FRs: 2,2′,4,4′-tetrabromodiphenylether (BDE-47), 2,2′,4,4′,5-pentabromodiphenylether (BDE-99), tetrabromobisphenol A, triphenyl phosphate, tris(2-butoxyethyl) phosphate and its metabolite bis-(2-butoxyethyl) phosphate, isodecyl diphenyl phosphate, triphenyl isopropylated phosphate, tricresyl phosphate, tris(1,3-dichloro-2-propyl) phosphate, tert-butylphenyl diphenyl phosphate, 2-ethylhexyl diphenyl phosphate, tris(1-chloroisopropyl) phosphate, and tris(2-chloroethyl) phosphate. Therefore, we used a human cell–based developmental neurotoxicity (DNT) in vitro battery covering a large variety of neurodevelopmental endpoints. Potency according to the respective most sensitive benchmark concentration (BMC) across the battery ranked from <1 μM (5 FRs), 1<10 μM (7 FRs) to the >10 μM range (3 FRs). Evaluation of the data with the ToxPi tool revealed a distinct ranking (a) than with the BMC and (b) compared to the ToxCast data, suggesting that DNT hazard of these FRs is not well predicted by ToxCast assays. Extrapolating the DNT in vitro battery BMCs to human FR exposure via breast milk suggests low risk for individual compounds. However, it raises a potential concern for real-life mixture exposure, especially when different compounds converge through diverse modes-of-action on common endpoints, like oligodendrocyte differentiation in this study. This case study using FRs suggests that human cell–based DNT in vitro battery is a promising approach for neurodevelopmental hazard assessment and compound prioritization in risk assessment.
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Environmentally relevant developmental methylmercury exposures alter neuronal differentiation in a human-induced pluripotent stem cell model. Food Chem Toxicol 2021; 152:112178. [PMID: 33831500 DOI: 10.1016/j.fct.2021.112178] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 03/15/2021] [Accepted: 03/30/2021] [Indexed: 12/14/2022]
Abstract
Developmental methylmercury (MeHg) exposure selectively targets the cerebral and cerebellar cortices, as seen by disruption of cytoarchitecture and glutamatergic (GLUergic) neuron hypoplasia. To begin to understand the mechanisms of this loss of GLUergic neurons, we aimed to develop a model of developmental MeHg neurotoxicity in human-induced pluripotent stem cells differentiating into cortical GLUergic neurons. Three dosing paradigms at 0.1 μM and 1.0 μM MeHg, which span different stages of neurodevelopment and reflect toxicologically relevant accumulation levels seen in human studies and mammalian models, were established. With these exposure paradigms, no changes were seen in commonly studied endpoints of MeHg toxicity, including viability, proliferation, and glutathione levels. However, MeHg exposure induced changes in mitochondrial respiration and glycolysis and in markers of neuronal differentiation. Our novel data suggests that GLUergic neuron hypoplasia seen with MeHg toxicity may be due to the partial inhibition of neuronal differentiation, given the increased expression of the early dorsal forebrain marker FOXG1 and corresponding decrease in expression on neuronal markers MAP2 and DCX and the deep layer cortical neuronal marker TBR1. Future studies should examine the persistent and latent functional effects of this MeHg-induced disruption of neuronal differentiation as well as transcriptomic and metabolomic alterations that may mediate MeHg toxicity.
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Zare Jeddi M, Hopf NB, Viegas S, Price AB, Paini A, van Thriel C, Benfenati E, Ndaw S, Bessems J, Behnisch PA, Leng G, Duca RC, Verhagen H, Cubadda F, Brennan L, Ali I, David A, Mustieles V, Fernandez MF, Louro H, Pasanen-Kase R. Towards a systematic use of effect biomarkers in population and occupational biomonitoring. ENVIRONMENT INTERNATIONAL 2021; 146:106257. [PMID: 33395925 DOI: 10.1016/j.envint.2020.106257] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 09/25/2020] [Accepted: 10/30/2020] [Indexed: 06/12/2023]
Abstract
Effect biomarkers can be used to elucidate relationships between exposure to environmental chemicals and their mixtures with associated health outcomes, but they are often underused, as underlying biological mechanisms are not understood. We aim to provide an overview of available effect biomarkers for monitoring chemical exposures in the general and occupational populations, and highlight their potential in monitoring humans exposed to chemical mixtures. We also discuss the role of the adverse outcome pathway (AOP) framework and physiologically based kinetic and dynamic (PBK/D) modelling to strengthen the understanding of the biological mechanism of effect biomarkers, and in particular for use in regulatory risk assessments. An interdisciplinary network of experts from the European chapter of the International Society for Exposure Science (ISES Europe) and the Organization for Economic Co-operation and Development (OECD) Occupational Biomonitoring activity of Working Parties of Hazard and Exposure Assessment group worked together to map the conventional framework of biomarkers and provided recommendations for their systematic use. We summarized the key aspects of this work here, and discussed these in three parts. Part I, we inventory available effect biomarkers and promising new biomarkers for the general population based on the H2020 Human Biomonitoring for Europe (HBM4EU) initiative. Part II, we provide an overview AOP and PBK/D modelling use that improved the selection and interpretation of effect biomarkers. Part III, we describe the collected expertise from the OECD Occupational Biomonitoring subtask effect biomarkers in prioritizing relevant mode of actions (MoAs) and suitable effect biomarkers. Furthermore, we propose a tiered risk assessment approach for occupational biomonitoring. Several effect biomarkers, especially for use in occupational settings, are validated. They offer a direct assessment of the overall health risks associated with exposure to chemicals, chemical mixtures and their transformation products. Promising novel effect biomarkers are emerging for biomonitoring of the general population. Efforts are being dedicated to prioritizing molecular and biochemical effect biomarkers that can provide a causal link in exposure-health outcome associations. This mechanistic approach has great potential in improving human health risk assessment. New techniques such as in silico methods (e.g. QSAR, PBK/D modelling) as well as 'omics data will aid this process. Our multidisciplinary review represents a starting point for enhancing the identification of effect biomarkers and their mechanistic pathways following the AOP framework. This may help in prioritizing the effect biomarker implementation as well as defining threshold limits for chemical mixtures in a more structured way. Several ex vivo biomarkers have been proposed to evaluate combined effects including genotoxicity and xeno-estrogenicity. There is a regulatory need to derive effect-based trigger values using the increasing mechanistic knowledge coming from the AOP framework to address adverse health effects due to exposure to chemical mixtures. Such a mechanistic strategy would reduce the fragmentation observed in different regulations. It could also stimulate a harmonized use of effect biomarkers in a more comparable way, in particular for risk assessments to chemical mixtures.
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Affiliation(s)
- Maryam Zare Jeddi
- Unit of Biostatistics, Epidemiology and Public Health, Department of Cardio-Thoraco-Vascular Sciences and Public Health, University of Padova, Italy
| | - Nancy B Hopf
- Center for Primary Care and Public Health (Unisanté), University of Lausanne, Lausanne, Epalinges, Switzerland
| | - Susana Viegas
- NOVA National School of Public Health, Public Health Research Centre, Universidade NOVA de Lisboa, 1600-560 Lisbon, Portugal; Comprehensive Health Research Center (CHRC), 1150-090 Lisbon, Portugal; H&TRC-Health & Technology Research Center, ESTeSL-Escola Superior de Tecnologia da Saúde, Instituto Politécnico de Lisboa, 1990-096 Lisbon, Portugal
| | - Anna Bal Price
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | - Alicia Paini
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | - Christoph van Thriel
- Leibniz Research Centre for Working Environment and Human Factors at the Technical University of Dortmund (IfADo), Ardeystrasse 67, 44139 Dortmund, Germany
| | - Emilio Benfenati
- Laboratory of Environmental Chemistry and Toxicology, Istituto Di Ricerche Farmacologiche Mario Negri IRCCS, Via La Masa, 19, 20156 Milano, Italy
| | - Sophie Ndaw
- INRS-French National Research and Safety Institute, France
| | - Jos Bessems
- VITO - Flemish Institute for Technological Research, Belgium
| | - Peter A Behnisch
- BioDetection Systems b.v., Science Park 406, 1098 XH Amsterdam, the Netherlands
| | - Gabriele Leng
- Currenta GmbH Co. OHG, Institute of Biomonitoring, Leverkusen, Germany
| | - Radu-Corneliu Duca
- Unit Environmental Hygiene and Human Biological Monitoring, Department of Health Protection, National Health Laboratory, Dudelange, Luxembourg
| | - Hans Verhagen
- Food Safety & Nutrition Consultancy (FSNConsultancy), Zeist, the Netherlands
| | - Francesco Cubadda
- Istituto Superiore di Sanità-National Institute of Health, Rome, Italy
| | - Lorraine Brennan
- School of Agriculture and Food Science, Institute of Food and Health, University College Dublin, Dublin, Ireland
| | - Imran Ali
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Arthur David
- Univ Rennes, Inserm, EHESP, Irset (Institut de Recherche en Santé, Environnement et Travail)-UMR_S 1085, F-35000 Rennes, France
| | - Vicente Mustieles
- University of Granada, Center for Biomedical Research (CIBM), Granada, Spain; Consortium for Biomedical Research in Epidemiology & Public Health (CIBERESP), Madrid, Spain
| | - Mariana F Fernandez
- University of Granada, Center for Biomedical Research (CIBM), Granada, Spain; Consortium for Biomedical Research in Epidemiology & Public Health (CIBERESP), Madrid, Spain
| | - Henriqueta Louro
- National Institute of Health Dr. Ricardo Jorge, Department of Human Genetics, Lisboa and ToxOmics - Centre for Toxicogenomics and Human Health, NOVA Medical School, Universidade Nova de Lisboa, Portugal
| | - Robert Pasanen-Kase
- State Secretariat for Economic Affairs (SECO), Labour Directorate Section Chemicals and Work (ABCH), Switzerland.
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Marx-Stoelting P, Solano MDLM, Aoyama H, Adams RH, Bal-Price A, Buschmann J, Chahoud I, Clark R, Fang T, Fujiwara M, Gelinsky M, Grote K, Horimoto M, Bennekou SH, Kellner R, Kuwagata M, Leist M, Lang A, Li W, Mantovani A, Makris SL, Paumgartten F, Perron M, Sachana M, Schmitt A, Schneider S, Schönfelder G, Schulze F, Shiota K, Solecki R. 25th anniversary of the Berlin workshop on developmental toxicology: DevTox database update, challenges in risk assessment of developmental neurotoxicity and alternative methodologies in bone development and growth. Reprod Toxicol 2020; 100:155-162. [PMID: 33278556 DOI: 10.1016/j.reprotox.2020.11.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 11/06/2020] [Accepted: 11/08/2020] [Indexed: 12/26/2022]
Abstract
25 years after the first Berlin Workshop on Developmental Toxicity this 10th Berlin Workshop aimed to bring together international experts from authorities, academia and industry to consider scientific, methodologic and regulatory aspects in risk assessment of developmental toxicity and to debate alternative strategies in testing developmental effects in the future. Proposals for improvement of the categorization of developmental effects were discussed as well as the update of the DevTox database as valuable tool for harmonization. The development of adverse outcome pathways relevant to developmental neurotoxicity (DNT) was debated as a fundamental improvement to guide the screening and testing for DNT using alternatives to animal methods. A further focus was the implementation of an in vitro mechanism-based battery, which can support various regulatory applications associated with the assessment of chemicals and mixtures. More interdisciplinary and translation research should be initiated to accelerate the development of new technologies to test developmental toxicity. Technologies in the pipeline are (i) high throughput imaging techniques, (ii) models for DNT screening tests, (iii) use of computer tomography for assessment of thoracolumbar supernumerary ribs in animal models, and (iv) 3D biofabrication of bone development and regeneration tissue models. In addition, increased collaboration with the medical community was suggested to improve the relevance of test results to humans and identify more clinically relevant endpoints. Finally, the participants agreed that this conference facilitated better understanding innovative approaches that can be useful for the identification of developmental health risks due to exposure to chemical substances.
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Affiliation(s)
| | | | | | - Ralf H Adams
- Max Planck Institute for Molecular Biomedicine, Muenster, Germany
| | - Anna Bal-Price
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | | | - Ibrahim Chahoud
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität Zu Berlin, and Berlin Institute of Health, Germany
| | - Ruth Clark
- Ruth Clark Associates Ltd., United Kingdom
| | - Tian Fang
- NHC Key Lab. of Reproduction Regulation (Shanghai Institute of Planned Parenthood Research), Fudan University, China
| | | | | | - Konstanze Grote
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität Zu Berlin, and Berlin Institute of Health, Germany
| | | | | | - Rupert Kellner
- Fraunhofer Institute for Toxicology and Experimental Medicine, Hannover, Germany
| | | | | | - Annemarie Lang
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität Zu Berlin, and Berlin Institute of Health, Germany
| | - Weihua Li
- NHC Key Lab. of Reproduction Regulation (Shanghai Institute of Planned Parenthood Research), Fudan University, China
| | | | - Susan L Makris
- U.S. Environmental Protection Agency, Office of Research and Development, Center for Public Health and Environmental Assessment, Washington, D.C., USA
| | | | - Monique Perron
- U.S. Environmental Protection Agency, Office of Pesticides Programs, Washington, D.C, USA
| | - Magdalini Sachana
- Organisation for Economic Co-operation and Development (OECD), Environment Health and Safety Division, Paris, France
| | - Anne Schmitt
- German Federal Institute for Risk Assessment, Berlin, Germany
| | | | - Gilbert Schönfelder
- German Federal Institute for Risk Assessment, Berlin, Germany; Charité - Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität Zu Berlin, and Berlin Institute of Health, Germany
| | - Frank Schulze
- German Federal Institute for Risk Assessment, Berlin, Germany
| | | | - Roland Solecki
- German Federal Institute for Risk Assessment, Berlin, Germany
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Rosca A, Coronel R, Moreno M, González R, Oniga A, Martín A, López V, González MDC, Liste I. Impact of environmental neurotoxic: current methods and usefulness of human stem cells. Heliyon 2020; 6:e05773. [PMID: 33376823 PMCID: PMC7758368 DOI: 10.1016/j.heliyon.2020.e05773] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 11/10/2020] [Accepted: 12/15/2020] [Indexed: 12/12/2022] Open
Abstract
The development of central nervous system is a highly coordinated and complex process. Any alteration of this process can lead to disturbances in the structure and function of the brain, which can cause deficits in neurological development, resulting in neurodevelopmental disorders, including, for example, autism or attention-deficit hyperactivity disorder. Exposure to certain chemicals during the fetal period and childhood is known to cause developmental neurotoxicity and has serious consequences that persist into adult life. For regulatory purposes, determination of the potential for developmental neurotoxicity is performed according the OECD Guideline 426, in which the test substance is administered to animals during gestation and lactation. However, these animal models are expensive, long-time consuming and may not reflect the physiology in humans; that makes it an unsustainable model to test the large amount of existing chemical products, hence alternative models to the use of animals are needed. One of the most promising methods is based on the use of stem cell technology. Stem cells are undifferentiated cells with the ability to self-renew and differentiate into more specialized cell types. Because of these properties, these cells have gained increased attention as possible therapeutic agents or as disease models. Here, we provide an overview of the current models both animal and cellular, available to study developmental neurotoxicity and review in more detail the usefulness of human stem cells, their properties and how they are becoming an alternative to evaluate and study the mechanisms of action of different environmental toxicants.
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Affiliation(s)
- Andreea Rosca
- Unidad de Regeneración Neural, Unidad Funcional de Investigación de Enfermedades Crónicas (UFIEC), Instituto de Salud Carlos III, Madrid, Spain
- Toxicología Ambiental, Centro Nacional de Sanidad Ambiental, Instituto de Salud Carlos III, Madrid, Spain
| | - Raquel Coronel
- Unidad de Regeneración Neural, Unidad Funcional de Investigación de Enfermedades Crónicas (UFIEC), Instituto de Salud Carlos III, Madrid, Spain
| | - Miryam Moreno
- Unidad de Regeneración Neural, Unidad Funcional de Investigación de Enfermedades Crónicas (UFIEC), Instituto de Salud Carlos III, Madrid, Spain
| | - Rosa González
- Unidad de Biología Computacional, Unidad Funcional de Investigación de Enfermedades Crónicas (UFIEC), Instituto de Salud Carlos III, Madrid, Spain
| | - Andreea Oniga
- Toxicología Ambiental, Centro Nacional de Sanidad Ambiental, Instituto de Salud Carlos III, Madrid, Spain
| | - Alberto Martín
- Instituto de Investigación de Enfermedades Raras (IIER), Instituto de Salud Carlos III, Madrid, Spain
| | - Victoria López
- Unidad de Biología Computacional, Unidad Funcional de Investigación de Enfermedades Crónicas (UFIEC), Instituto de Salud Carlos III, Madrid, Spain
| | - María del Carmen González
- Toxicología Ambiental, Centro Nacional de Sanidad Ambiental, Instituto de Salud Carlos III, Madrid, Spain
| | - Isabel Liste
- Unidad de Regeneración Neural, Unidad Funcional de Investigación de Enfermedades Crónicas (UFIEC), Instituto de Salud Carlos III, Madrid, Spain
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Attoff K, Johansson Y, Cediel-Ulloa A, Lundqvist J, Gupta R, Caiment F, Gliga A, Forsby A. Acrylamide alters CREB and retinoic acid signalling pathways during differentiation of the human neuroblastoma SH-SY5Y cell line. Sci Rep 2020; 10:16714. [PMID: 33028897 PMCID: PMC7541504 DOI: 10.1038/s41598-020-73698-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 09/21/2020] [Indexed: 01/06/2023] Open
Abstract
Acrylamide (ACR) is a known neurotoxicant which crosses the blood–brain barrier, passes the placenta and has been detected in breast milk. Hence, early-life exposure to ACR could lead to developmental neurotoxicity. The aim of this study was to elucidate if non-cytotoxic concentrations of ACR alter neuronal differentiation by studying gene expression of markers significant for neurodevelopment in the human neuroblastoma SH-SY5Y cell model. Firstly, by using RNASeq we identified two relevant pathways that are activated during 9 days of retinoic acid (RA) induced differentiation i.e. RA receptor (RAR) activation and the cAMP response element-binding protein (CREB) signalling pathways. Next, by qPCR we showed that 1 and 70 µM ACR after 9 days exposure alter the expression of 13 out of 36 genes in the RAR activation pathway and 18 out of 47 in the CREB signalling pathway. Furthermore, the expression of established neuronal markers i.e. BDNF, STXBP2, STX3, TGFB1 and CHAT were down-regulated. Decreased protein expression of BDNF and altered ratio of phosphorylated CREB to total CREB were confirmed by western blot. Our results reveal that micromolar concentrations of ACR sustain proliferation, decrease neurite outgrowth and interfere with signalling pathways involved in neuronal differentiation in the SH-SY5Y cell model.
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Affiliation(s)
- Kristina Attoff
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Ylva Johansson
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Andrea Cediel-Ulloa
- Unit of Toxicology Sciences, Swedish Toxicology Sciences Research Center (Swetox), Karolinska Institutet, Södertälje, Sweden.,Department for organismal biology, Uppsala University, Uppsala, Sweden
| | - Jessica Lundqvist
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden.,Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Rajinder Gupta
- Department of Toxicogenomics, School of Oncology and Developmental Biology (GROW), Maastricht University, Maastricht, The Netherlands
| | - Florian Caiment
- Department of Toxicogenomics, School of Oncology and Developmental Biology (GROW), Maastricht University, Maastricht, The Netherlands
| | - Anda Gliga
- Unit of Toxicology Sciences, Swedish Toxicology Sciences Research Center (Swetox), Karolinska Institutet, Södertälje, Sweden
| | - Anna Forsby
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden. .,Department for organismal biology, Uppsala University, Uppsala, Sweden.
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Kamata S, Hashiyama R, Hana-Ika H, Ohkubo I, Saito R, Honda A, Anan Y, Akahoshi N, Noguchi K, Kanda Y, Ishii I. Cytotoxicity comparison of 35 developmental neurotoxicants in human induced pluripotent stem cells (iPSC), iPSC-derived neural progenitor cells, and transformed cell lines. Toxicol In Vitro 2020; 69:104999. [PMID: 32949729 DOI: 10.1016/j.tiv.2020.104999] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 08/05/2020] [Accepted: 09/09/2020] [Indexed: 11/27/2022]
Abstract
The Organization for Economic Co-operation and Development (OECD) test guideline 426 for developmental neurotoxicity (DNT) of industrial/environmental chemicals depends primarily on animal experimentation. This requirement raises various critical issues, such as high cost, long duration, the sacrifice of large numbers of animals, and interspecies differences. This study demonstrates an alternative protocol that is simple, quick, less expensive, and standardized to evaluate DNT of many chemicals using human induced pluripotent stem cells (iPSC) and their differentiation to neural progenitor cells (NPC). Initially, concentration-dependent cytotoxicity of 35 DNT chemicals, including industrial materials, insecticides, and clinical drugs, were compared among iPSC, NPC, and two transformed cells, Cos-7 and HepG2, using tetrazolium dye (MTS)-reducing colorimetric and ATP luciferase assays, and IC50 values were calculated. Next, inhibitory effects of the 14 representative chemicals (mainly insecticides) on iPSC differentiation to NPC were evaluated by measuring altered expression of neural differentiation and undifferentiation marker genes. Results show that both iPSC and NPC were much more sensitive to most DNT chemicals than the transformed cells, and 14 chemicals induced differential patterns of marker gene expression, highlighting the validity and utility of the protocol for evaluation and classification of DNT chemicals and preclinical DNT tests for safety assessment.
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Affiliation(s)
- Shotaro Kamata
- Department of Health Chemistry, Showa Pharmaceutical University, Machida, Tokyo 194-8543, Japan
| | - Reina Hashiyama
- Department of Health Chemistry, Showa Pharmaceutical University, Machida, Tokyo 194-8543, Japan
| | - Hiroto Hana-Ika
- Department of Health Chemistry, Showa Pharmaceutical University, Machida, Tokyo 194-8543, Japan
| | - Issei Ohkubo
- Department of Health Chemistry, Showa Pharmaceutical University, Machida, Tokyo 194-8543, Japan
| | - Ryota Saito
- Department of Health Chemistry, Showa Pharmaceutical University, Machida, Tokyo 194-8543, Japan
| | - Akihiro Honda
- Department of Health Chemistry, Showa Pharmaceutical University, Machida, Tokyo 194-8543, Japan
| | - Yasumi Anan
- Department of Health Chemistry, Showa Pharmaceutical University, Machida, Tokyo 194-8543, Japan
| | - Noriyuki Akahoshi
- Department of Health Chemistry, Showa Pharmaceutical University, Machida, Tokyo 194-8543, Japan
| | - Kohji Noguchi
- Laboratory of Molecular Target Therapy, Faculty of Pharmaceutical Sciences, Tokyo University of Science, Noda, Chiba 278-8510, Japan
| | - Yasunari Kanda
- Division of Pharmacology, National Institute of Health Sciences, Kawasaki, Kanagawa 210-9501, Japan.
| | - Isao Ishii
- Department of Health Chemistry, Showa Pharmaceutical University, Machida, Tokyo 194-8543, Japan.
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An efficient neuron-astrocyte differentiation protocol from human embryonic stem cell-derived neural progenitors to assess chemical-induced developmental neurotoxicity. Reprod Toxicol 2020; 98:107-116. [PMID: 32931842 DOI: 10.1016/j.reprotox.2020.09.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 08/13/2020] [Accepted: 09/07/2020] [Indexed: 01/10/2023]
Abstract
Human embryonic stem cell neuronal differentiation models provide promising in vitro tools for the prediction of developmental neurotoxicity of chemicals. Such models mimic essential elements of human relevant neuronal development, including the differentiation of a variety of brain cell types and their neuronal network formation as evidenced by specific gene and protein biomarkers. However, the reproducibility and lengthy culture duration of cell models present drawbacks and delay regulatory implementation. Here we present a relatively short and robust protocol to differentiate H9-derived neural progenitor cells (NPCs) into a neuron-astrocyte co-culture. When frozen-stored NPCs were re-cultured and induced into neuron-astrocyte differentiation, they showed gene- and protein expression typical for these cells, and most notably they exhibited spontaneous electrical activity within three days of culture as measured by a multi-well micro-electrode array. Modulating the ratio of astrocytes and neurons through different growth factors including glial cell line-derived neurotrophic factor (GDNF), brain-derived neurotrophic factor (BDNF), and ciliary neurotrophic factor (CNTF) did not compromise the ability to develop spontaneous electrical activity. This robust neuronal differentiation model may serve as a functional component of a testing strategy for unravelling mechanisms of developmental neurotoxicity.
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Paparella M, Bennekou SH, Bal-Price A. An analysis of the limitations and uncertainties of in vivo developmental neurotoxicity testing and assessment to identify the potential for alternative approaches. Reprod Toxicol 2020; 96:327-336. [PMID: 32781019 DOI: 10.1016/j.reprotox.2020.08.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 06/27/2020] [Accepted: 08/05/2020] [Indexed: 10/23/2022]
Abstract
Limitations of regulatory in vivo developmental neurotoxicity (DNT) testing and assessment are well known, such as the 3Rs conflict, low throughput, high costs, high specific expertise needed and the lack of deeper mechanistic information. Moreover, the standard in vivo DNT data variability and in the experimental animal to human real life extrapolation is uncertain. Here, knowledge about these limitations and uncertainties is systematically summarized using a tabular OECD format. We also outline a hypothesis how alternative, fit-for-purpose Integrated Approaches to Testing and Assessment (IATAs) for DNT could improve current standard animal testing: Relative gains in 3Rs compliance, reduced costs, higher throughput, improved basic study design, higher standardization of testing and assessment and validation without 3Rs conflict, increasing the availability and reliability of DNT data. This could allow a more reliable comparative toxicity assessment over a larger proportion of chemicals within our global environment. The use of early, mechanistic, sensitive indicators for potential DNT could better support human safety assessment and mixture extrapolation. Using kinetic modelling ideally these could provide - eventually context dependent - at least the same level of human health protection. Such new approaches could also lead to a new mechanistic understanding for chemical safety, permitting determination of a dose that is likely not to trigger defined toxicity traits or pathways, rather than a dose not causing the current apical organism endpoints. The manuscript shall motivate and guide the development of new alternative methods for IATAs with diverse applications and support decision-making for their regulatory acceptance.
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Affiliation(s)
- Martin Paparella
- Division of Medical Biochemistry, Biocenter, Medical University of Innsbruck, Innsbruck, Austria.
| | | | - Anna Bal-Price
- European Commission, Joint Research Centre (JRC), Ispra, Italy
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37
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Carlson LM, Champagne FA, Cory-Slechta DA, Dishaw L, Faustman E, Mundy W, Segal D, Sobin C, Starkey C, Taylor M, Makris SL, Kraft A. Potential frameworks to support evaluation of mechanistic data for developmental neurotoxicity outcomes: A symposium report. Neurotoxicol Teratol 2020; 78:106865. [PMID: 32068112 PMCID: PMC7160758 DOI: 10.1016/j.ntt.2020.106865] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 02/05/2020] [Accepted: 02/10/2020] [Indexed: 12/16/2022]
Abstract
A key challenge in systematically incorporating mechanistic data into human health assessments is that, compared to studies of apical health endpoints, these data are both more abundant (mechanistic studies routinely outnumber other studies by several orders of magnitude) and more heterogeneous (e.g. different species, test system, tissue, cell type, exposure paradigm, or specific assays performed). A structured decision-making process for organizing, integrating, and weighing mechanistic DNT data for use in human health risk assessments will improve the consistency and efficiency of such evaluations. At the Developmental Neurotoxicology Society (DNTS) 2016 annual meeting, a symposium was held to address the application of existing organizing principles and frameworks for evaluation of mechanistic data relevant to interpreting neurotoxicology data. Speakers identified considerations with potential to advance the use of mechanistic DNT data in risk assessment, including considering the context of each exposure, since epigenetics, tissue type, sex, stress, nutrition and other factors can modify toxicity responses in organisms. It was also suggested that, because behavior is a manifestation of complex nervous system function, the presence and absence of behavioral change itself could be used to organize the interpretation of multiple complex simultaneous mechanistic changes. Several challenges were identified with frameworks and their implementation, and ongoing research to develop these approaches represents an early step toward full evaluation of mechanistic DNT data for assessments.
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Affiliation(s)
- Laura M Carlson
- Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, RTP, NC.
| | | | - Deborah A Cory-Slechta
- Department of Environmental Medicine, University of Rochester Medical School Rochester, NY
| | - Laura Dishaw
- Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, RTP, NC
| | - Elaine Faustman
- School of Public Health, Institute for Risk Analysis and Risk Communication, University of Washington, Seattle, WA
| | - William Mundy
- Neurotoxicologist, Durham, NC (formerly National Health and Environmental Effects Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, RTP, NC))
| | - Deborah Segal
- Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Washington, DC
| | - Christina Sobin
- Dept of Public Health Sciences, The University of Texas at El Paso, El Paso, Texas, USA
| | - Carol Starkey
- Booz Allen Hamilton (formerly research fellow with the Oak Ridge Institute for Science and Engineering (ORISE) with Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Washington DC))
| | - Michele Taylor
- Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, RTP, NC
| | - Susan L Makris
- Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Washington, DC
| | - Andrew Kraft
- Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Washington, DC; Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, RTP, NC
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38
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Patisaul HB. Achieving CLARITY on bisphenol A, brain and behaviour. J Neuroendocrinol 2020; 32:e12730. [PMID: 31063678 PMCID: PMC10947534 DOI: 10.1111/jne.12730] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Revised: 04/28/2019] [Accepted: 05/02/2019] [Indexed: 12/18/2022]
Abstract
There is perhaps no endocrine disrupting chemical more controversial than bisphenol A (BPA). Comprising a high-volume production chemical used in a variety of applications, BPA has been linked to a litany of adverse health-related outcomes, including effects on brain sexual differentiation and behaviour. Risk assessors preferentially rely on classical guideline-compliant toxicity studies over studies published by academic scientists, and have generally downplayed concerns about the potential risks that BPA poses to human health. It has been argued, however, that, because traditional toxicity studies rarely contain neural endpoints, and only a paucity of endocrine-sensitive endpoints, they are incapable of fully evaluating harm. To address current controversies on the safety of BPA, the United States National Institute of Environmental Health Sciences, the National Toxicology Program (NTP), and the US Food and Drug Administration established the Consortium Linking Academic and Regulatory Insights on BPA Toxicity (CLARITY-BPA). CLARITY-BPA performed a classical regulatory-style toxicology study (Core study) in conjunction with multiple behavioural, molecular and cellular studies conducted by academic laboratories (grantee studies) using a collaboratively devised experimental framework and the same animals and tissues. This review summarises the results from the grantee studies that focused on brain and behaviour. Evidence of altered neuroendocrine development, including age- and sex-specific expression of oestrogen receptor (ER)α and ERβ, and the abrogation of brain and behavioural sexual dimorphisms, supports the conclusion that developmental BPA exposure, even at doses below what regulatory agencies regard as "safe" for humans, contribute to brain and behavioural change. The consistency and the reproducibility of the effects across CLARITY-BPA and prior studies using the same animal strain and almost identical experimental conditions are compelling. Combined analysis of all of the data from the CLARITY-BPA project is underway at the NTP and a final report expected in late 2019.
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Affiliation(s)
- Heather B Patisaul
- Department of Biological Sciences, Center for Human Health and the Environment, North Carolina State University, Raleigh, North Carolina
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Behl M, Ryan K, Hsieh JH, Parham F, Shapiro AJ, Collins BJ, Sipes NS, Birnbaum LS, Bucher JR, Foster PMD, Walker NJ, Paules RS, Tice RR. Screening for Developmental Neurotoxicity at the National Toxicology Program: The Future Is Here. Toxicol Sci 2019; 167:6-14. [PMID: 30496580 DOI: 10.1093/toxsci/kfy278] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The National Toxicology Program (NTP) receives requests to evaluate chemicals with potential to cause adverse health effects, including developmental neurotoxicity (DNT). Some recent requests have included classes of chemicals such as flame retardants, polycyclic aromatic compounds, perfluoroalkyl substances, and bisphenol A analogs with approximately 20-50 compounds per class, many of which include commercial mixtures. However, all the compounds within a class cannot be tested using traditional DNT animal testing guideline studies due to resource and time limitations. Hence, a rapid and biologically relevant screening approach is required to prioritize compounds for further in vivo testing. Because neurodevelopment is a complex process involving multiple distinct cellular processes, one assay will unlikely address the complexity. Hence, the NTP sought to characterize a battery of in vitro and alternative animal assays to quantify chemical effects on a variety of neurodevelopmental processes. A culmination of this effort resulted in a NTP-hosted collaborative project with approximately 40 participants spanning across domains of academia, industry, government, and regulatory agencies; collaborators presented data on cell-based assays and alternative animal models that was generated using a targeted set of compounds provided by the NTP. The NTP analyzed the assay results using benchmark concentration (BMC) modeling to be able to compare results across the divergent assays. The results were shared with the contributing researchers on a private web application during the workshop, and are now publicly available. This article highlights the overview and goals of the project, and describes the NTP's approach in creating the chemical library, development of NTPs data analysis strategy, and the structure of the web application. Finally, we discuss key issues with emphasis on the utility of this approach, and knowledge gaps that need to be addressed for its use in regulatory decision making.
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Affiliation(s)
- Mamta Behl
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
| | - Kristen Ryan
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
| | - Jui-Hua Hsieh
- Kelly Government Solutions, Durham, North Carolina 27709
| | - Frederick Parham
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
| | - Andrew J Shapiro
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
| | - Bradley J Collins
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
| | - Nisha S Sipes
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
| | - Linda S Birnbaum
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
| | - John R Bucher
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
| | - Paul M D Foster
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
| | - Nigel J Walker
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
| | - Richard S Paules
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
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Koiwa J, Shiromizu T, Adachi Y, Ikejiri M, Nakatani K, Tanaka T, Nishimura Y. Generation of a Triple-Transgenic Zebrafish Line for Assessment of Developmental Neurotoxicity during Neuronal Differentiation. Pharmaceuticals (Basel) 2019; 12:E145. [PMID: 31554324 PMCID: PMC6958351 DOI: 10.3390/ph12040145] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 09/19/2019] [Accepted: 09/22/2019] [Indexed: 12/15/2022] Open
Abstract
: The developing brain is extremely sensitive to many chemicals. Exposure to neurotoxicants during development has been implicated in various neuropsychiatric and neurological disorders, including autism spectrum disorders and schizophrenia. Various screening methods have been used to assess the developmental neurotoxicity (DNT) of chemicals, with most assays focusing on cell viability, apoptosis, proliferation, migration, neuronal differentiation, and neuronal network formation. However, assessment of toxicity during progenitor cell differentiation into neurons, astrocytes, and oligodendrocytes often requires immunohistochemistry, which is a reliable but labor-intensive and time-consuming assay. Here, we report the development of a triple-transgenic zebrafish line that expresses distinct fluorescent proteins in neurons (Cerulean), astrocytes (mCherry), and oligodendrocytes (mCitrine), which can be used to detect DNT during neuronal differentiation. Using in vivo fluorescence microscopy, we could detect DNT by 6 of the 10 neurotoxicants tested after exposure to zebrafish from 12 h to 5 days' post-fertilization. Moreover, the chemicals could be clustered into three main DNT groups based on the fluorescence pattern: (i) inhibition of neuron and oligodendrocyte differentiation and stimulation of astrocyte differentiation; (ii) inhibition of neuron and oligodendrocyte differentiation; and (iii) inhibition of neuron and astrocyte differentiation, which suggests that reporter expression reflects the toxicodynamics of the chemicals. Thus, the triple-transgenic zebrafish line developed here may be a useful tool to assess DNT during neuronal differentiation.
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Affiliation(s)
- Junko Koiwa
- Department of Integrative Pharmacology, Mie University Graduate School of Medicine, Tsu, Mie 514-8507, Japan.
| | - Takashi Shiromizu
- Department of Integrative Pharmacology, Mie University Graduate School of Medicine, Tsu, Mie 514-8507, Japan.
| | - Yuka Adachi
- Department of Integrative Pharmacology, Mie University Graduate School of Medicine, Tsu, Mie 514-8507, Japan.
| | - Makoto Ikejiri
- Department of Central Laboratory, Mie University Hospital, Tsu, Mie 514-8507, Japan.
| | - Kaname Nakatani
- Department of Genomic Medicine, Mie University Hospital, Tsu, Mie 514-8507, Japan.
| | - Toshio Tanaka
- Department of Systems Pharmacology, Mie University Graduate School of Medicine, Tsu, Mie 514-8507, Japan.
| | - Yuhei Nishimura
- Department of Integrative Pharmacology, Mie University Graduate School of Medicine, Tsu, Mie 514-8507, Japan.
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Bennekou SH. Moving towards a holistic approach for human health risk assessment - Is the current approach fit for purpose? EFSA J 2019; 17:e170711. [PMID: 32626448 PMCID: PMC7015490 DOI: 10.2903/j.efsa.2019.e170711] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
It is recognised that new scientific improvements and their integration in risk assessment, as outlined in the National Academies of Sciences, Engineering and Medicine 2017 report, have the potential to improve human health risk assessments by enabling a mechanistic understanding of adverse effects and more accurate predictions of biological responses. Here, I discuss why such improvements are needed and can ease a paradigm shift in human health risk assessment. The current approach to human health risk assessment is limited by several elements: (1) the relevance of data is debatable, as they are largely based on in vivo animal models that are poorly predictive for complex endpoints, raise challenges with regard to interspecies extrapolations, and are seldom informative of the mechanism underlying the observed effects; (2) lack of flexibility in data requirements by regulators, which limits the uptake of new scientific developments in a timely manner; and (3) lack of data accessibility, which makes data integration difficult. However, mechanistic-based assessments are currently conducted for the identification of endocrine disruptors and are developed for addressing developmental neurotoxicity. Such assessments can serve as examples for changing the paradigm of risk assessment. There are several opportunities for improvement, such as: make regulatory standard requirements less prescriptive; enhance and use the opportunities for read-across; analyse and quantify uncertainties in order to benchmark new approach methods to the current system; better integrate screening methods early in regulatory assessments and decision-making; and develop more adverse outcome pathways in order to link new approach methods with the current approach and ultimately make it possible to base regulatory decisions on early key events of a toxicity pathway.
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