451
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Willett C, Caverly Rae J, Goyak KO, Minsavage G, Westmoreland C, Andersen M, Avigan M, Duché D, Harris G, Hartung T, Jaeschke H, Kleensang A, Landesmann B, Martos S, Matevia M, Toole C, Rowan A, Schultz T, Seed J, Senior J, Shah I, Subramanian K, Vinken M, Watkins P. Building shared experience to advance practical application of pathway-based toxicology: liver toxicity mode-of-action. ALTEX-ALTERNATIVES TO ANIMAL EXPERIMENTATION 2014; 31:500-19. [PMID: 24535319 DOI: 10.14573/altex.1401281] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 02/11/2014] [Indexed: 11/23/2022]
Abstract
A workshop sponsored by the Human Toxicology Project Consortium (HTPC), "Building Shared Experience to Advance Practical Application of Pathway-Based Toxicology: Liver Toxicity Mode-of-Action" brought together experts from a wide range of perspectives to inform the process of pathway development and to advance two prototype pathways initially developed by the European Commission Joint Research Center (JRC): liver-specific fibrosis and steatosis. The first half of the workshop focused on the theory and practice of pathway development; the second on liver disease and the two prototype pathways. Participants agreed pathway development is extremely useful for organizing information and found that focusing the theoretical discussion on a specific AOP is extremely helpful. In addition, it is important to include several perspectives during pathway development, including information specialists, pathologists, human health and environmental risk assessors, and chemical and product manufacturers, to ensure the biology is well captured and end use is considered.
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452
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Currie HN, Vrana JA, Han AA, Scardoni G, Boggs N, Boyd JW. An approach to investigate intracellular protein network responses. Chem Res Toxicol 2014; 27:17-26. [PMID: 24359296 DOI: 10.1021/tx400247g] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Modern toxicological evaluations have evolved to consider toxicity as a perturbation of biological pathways or networks. As such, toxicity testing approaches are shifting from common end point evaluations to pathway based approaches, where the degree of perturbation of select biological pathways is monitored. These new approaches are greatly increasing the data available to toxicologists, but methods of analyses to determine the inter-relationships between potentially affected pathways are needed to fully understand the consequences of exposure. An approach to construct dose-response curves that use graph theory to describe network perturbations among three disparate mitogen-activated protein kinase (MAPK) pathways is presented. Mitochondrial stress was induced in human hepatocytes (HepG2) by exposing the cells to increasing doses of the complex I inhibitor, deguelin. The relative phosphorylation responses of proteins involved in the regulation of the stress response were measured. Graph theory was applied to the phosphorylation data to obtain parameters describing the network perturbations at each individual dose tested. The graph theory results depicted the dynamic nature of the relationship between p38, JNK, and ERK1/2 under conditions of mitochondrial stress and revealed shifts in the relationships between these MAPK pathways at low doses. The inter-relationship, or crosstalk, among these 3 traditionally linear MAPK cascades was further probed by coexposing cells to deguelin plus SB202190 (JNK and p38 inhibitor) or deguelin plus SB202474 (JNK inhibitor). The cells exposed to deguelin plus SB202474 resulted in significantly decreased viability, which could be visualized and attributed to the decrease of ERK1/2 network centrality. The approach presented here allows for the construction and visualization of dose-response curves that describe network perturbations induced by chemical stress, which provides an informative and sensitive means of assessing toxicological effects on biological systems.
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Affiliation(s)
- Holly N Currie
- Department of Chemistry, West Virginia University , 217 Clark Hall, Prospect Street, Morgantown, West Virginia 26506, United States
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453
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Application of “Omics” Technologies to In Vitro Toxicology. METHODS IN PHARMACOLOGY AND TOXICOLOGY 2014. [DOI: 10.1007/978-1-4939-0521-8_18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/06/2022]
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454
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Alépée N, Bahinski A, Daneshian M, De Wever B, Fritsche E, Goldberg A, Hansmann J, Hartung T, Haycock J, Hogberg HT, Hoelting L, Kelm JM, Kadereit S, McVey E, Landsiedel R, Leist M, Lübberstedt M, Noor F, Pellevoisin C, Petersohn D, Pfannenbecker U, Reisinger K, Ramirez T, Rothen-Rutishauser B, Schäfer-Korting M, Zeilinger K, Zurich MG. State-of-the-art of 3D cultures (organs-on-a-chip) in safety testing and pathophysiology. ALTEX 2014; 31:441-77. [PMID: 25027500 PMCID: PMC4783151 DOI: 10.14573/altex.1406111] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 06/30/2014] [Indexed: 02/02/2023]
Abstract
Integrated approaches using different in vitro methods in combination with bioinformatics can (i) increase the success rate and speed of drug development; (ii) improve the accuracy of toxicological risk assessment; and (iii) increase our understanding of disease. Three-dimensional (3D) cell culture models are important building blocks of this strategy which has emerged during the last years. The majority of these models are organotypic, i.e., they aim to reproduce major functions of an organ or organ system. This implies in many cases that more than one cell type forms the 3D structure, and often matrix elements play an important role. This review summarizes the state of the art concerning commonalities of the different models. For instance, the theory of mass transport/metabolite exchange in 3D systems and the special analytical requirements for test endpoints in organotypic cultures are discussed in detail. In the next part, 3D model systems for selected organs--liver, lung, skin, brain--are presented and characterized in dedicated chapters. Also, 3D approaches to the modeling of tumors are presented and discussed. All chapters give a historical background, illustrate the large variety of approaches, and highlight up- and downsides as well as specific requirements. Moreover, they refer to the application in disease modeling, drug discovery and safety assessment. Finally, consensus recommendations indicate a roadmap for the successful implementation of 3D models in routine screening. It is expected that the use of such models will accelerate progress by reducing error rates and wrong predictions from compound testing.
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Affiliation(s)
| | - Anthony Bahinski
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, USA
| | - Mardas Daneshian
- Center for Alternatives to Animal Testing – Europe (CAAT-Europe), University of Konstanz, Konstanz, Germany
| | | | - Ellen Fritsche
- Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Alan Goldberg
- Center for Alternatives to Animal Testing (CAAT), Johns Hopkins University, Bloomberg School of Public Health, Baltimore, USA
| | - Jan Hansmann
- Department of Tissue Engineering and Regenerative Medicine, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Thomas Hartung
- Center for Alternatives to Animal Testing – Europe (CAAT-Europe), University of Konstanz, Konstanz, Germany,Center for Alternatives to Animal Testing (CAAT), Johns Hopkins University, Bloomberg School of Public Health, Baltimore, USA
| | - John Haycock
- Department of Materials Science of Engineering, University of Sheffield, Sheffield, UK
| | - Helena T. Hogberg
- Center for Alternatives to Animal Testing (CAAT), Johns Hopkins University, Bloomberg School of Public Health, Baltimore, USA
| | - Lisa Hoelting
- Doerenkamp-Zbinden Chair of in vitro Toxicology and Biomedicine, University of Konstanz, Konstanz, Germany
| | | | - Suzanne Kadereit
- Doerenkamp-Zbinden Chair of in vitro Toxicology and Biomedicine, University of Konstanz, Konstanz, Germany
| | - Emily McVey
- Board for the Authorization of Plant Protection Products and Biocides, Wageningen, The Netherlands
| | | | - Marcel Leist
- Center for Alternatives to Animal Testing – Europe (CAAT-Europe), University of Konstanz, Konstanz, Germany,Doerenkamp-Zbinden Chair of in vitro Toxicology and Biomedicine, University of Konstanz, Konstanz, Germany
| | - Marc Lübberstedt
- Bioreactor Group, Berlin-Brandenburg Center for Regenerative Therapies (BCRT), Charité Campus Virchow-Klinikum, Berlin, Germany
| | - Fozia Noor
- Biochemical Engineering, Saarland University, Saarbruecken, Germany
| | | | | | | | | | - Tzutzuy Ramirez
- BASF SE, Experimental Toxicology and Ecology, Ludwigshafen, Germany
| | | | - Monika Schäfer-Korting
- Institute for Pharmacy (Pharmacology and Toxicology), Freie Universität Berlin, Berlin, Germany
| | - Katrin Zeilinger
- Bioreactor Group, Berlin-Brandenburg Center for Regenerative Therapies (BCRT), Charité Campus Virchow-Klinikum, Berlin, Germany
| | - Marie-Gabriele Zurich
- Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland,Swiss Center for Applied Human Toxicology (SCAHT), University of Lausanne, Lausanne, Switzerland
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455
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Shah F, Greene N. Analysis of Pfizer Compounds in EPA’s ToxCast Chemicals-Assay Space. Chem Res Toxicol 2013; 27:86-98. [DOI: 10.1021/tx400343t] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Falgun Shah
- Compound Safety Prediction, Pfizer Global Research & Development, 558 Eastern Point Road, Groton, Connecticut 06340, United States
| | - Nigel Greene
- Compound Safety Prediction, Pfizer Global Research & Development, 558 Eastern Point Road, Groton, Connecticut 06340, United States
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456
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Ellis P, Fowler P, Booth E, Kidd D, Howe J, Doherty A, Scott A. Where will genetic toxicology testing be in 30 years’ time? Summary report of the 25th Industrial Genotoxicity Group Meeting, Royal Society of Medicine, London, November 9, 2011. Mutagenesis 2013; 29:73-7. [DOI: 10.1093/mutage/get057] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
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457
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Kleensang A, Maertens A, Rosenberg M, Fitzpatrick S, Lamb J, Auerbach S, Brennan R, Crofton KM, Gordon B, Fornace AJ, Gaido K, Gerhold D, Haw R, Henney A, Ma'ayan A, McBride M, Monti S, Ochs MF, Pandey A, Sharan R, Stierum R, Tugendreich S, Willett C, Wittwehr C, Xia J, Patton GW, Arvidson K, Bouhifd M, Hogberg HT, Luechtefeld T, Smirnova L, Zhao L, Adeleye Y, Kanehisa M, Carmichael P, Andersen ME, Hartung T. Pathways of Toxicity. ALTEX-ALTERNATIVES TO ANIMAL EXPERIMENTATION 2013; 31:53-61. [PMID: 24127042 DOI: 10.14573/altex.1309261] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 09/30/2013] [Indexed: 01/01/2023]
Abstract
Despite wide-spread consensus on the need to transform toxicology and risk assessment in order to keep pace with technological and computational changes that have revolutionized the life sciences, there remains much work to be done to achieve the vision of toxicology based on a mechanistic foundation. To this end, a workshop was organized to explore one key aspect of this transformation - the development of Pathways of Toxicity as a key tool for hazard identification based on systems biology. Several issues were discussed in depth in the workshop: The first was the challenge of formally defining the concept of a Pathway of Toxicity (PoT), as distinct from, but complementary to, other toxicological pathway concepts such as mode of action (MoA). The workshop came up with a preliminary definition of PoT as "A molecular definition of cellular processes shown to mediate adverse outcomes of toxicants". It is further recognized that normal physiological pathways exist that maintain homeostasis and these, sufficiently perturbed, can become PoT. Second, the workshop sought to define the adequate public and commercial resources for PoT information, including data, visualization, analyses, tools, and use-cases, as well as the kinds of efforts that will be necessary to enable the creation of such a resource. Third, the workshop explored ways in which systems biology approaches could inform pathway annotation, and which resources are needed and available that can provide relevant PoT information to the diverse user communities.
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Affiliation(s)
- Andre Kleensang
- Johns Hopkins University, Bloomberg School of Public Health, Center for Alternatives to Animal Testing, Baltimore, MD, USA
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458
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Ansari S, Binder J, Boue S, Di Fabio A, Hayes W, Hoeng J, Iskandar A, Kleiman R, Norel R, O'Neel B, Peitsch MC, Poussin C, Pratt D, Rhrissorrakrai K, Schlage WK, Stolovitzky G, Talikka M. On Crowd-verification of Biological Networks. Bioinform Biol Insights 2013; 7:307-25. [PMID: 24151423 PMCID: PMC3798292 DOI: 10.4137/bbi.s12932] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Biological networks with a structured syntax are a powerful way of representing biological information generated from high density data; however, they can become unwieldy to manage as their size and complexity increase. This article presents a crowd-verification approach for the visualization and expansion of biological networks. Web-based graphical interfaces allow visualization of causal and correlative biological relationships represented using Biological Expression Language (BEL). Crowdsourcing principles enable participants to communally annotate these relationships based on literature evidences. Gamification principles are incorporated to further engage domain experts throughout biology to gather robust peer-reviewed information from which relationships can be identified and verified. The resulting network models will represent the current status of biological knowledge within the defined boundaries, here processes related to human lung disease. These models are amenable to computational analysis. For some period following conclusion of the challenge, the published models will remain available for continuous use and expansion by the scientific community.
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459
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Yang Y, Maxwell A, Zhang X, Wang N, Perkins EJ, Zhang C, Gong P. Differential reconstructed gene interaction networks for deriving toxicity threshold in chemical risk assessment. BMC Bioinformatics 2013; 14 Suppl 14:S3. [PMID: 24268022 PMCID: PMC3851258 DOI: 10.1186/1471-2105-14-s14-s3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Background Pathway alterations reflected as changes in gene expression regulation and gene interaction can result from cellular exposure to toxicants. Such information is often used to elucidate toxicological modes of action. From a risk assessment perspective, alterations in biological pathways are a rich resource for setting toxicant thresholds, which may be more sensitive and mechanism-informed than traditional toxicity endpoints. Here we developed a novel differential networks (DNs) approach to connect pathway perturbation with toxicity threshold setting. Methods Our DNs approach consists of 6 steps: time-series gene expression data collection, identification of altered genes, gene interaction network reconstruction, differential edge inference, mapping of genes with differential edges to pathways, and establishment of causal relationships between chemical concentration and perturbed pathways. A one-sample Gaussian process model and a linear regression model were used to identify genes that exhibited significant profile changes across an entire time course and between treatments, respectively. Interaction networks of differentially expressed (DE) genes were reconstructed for different treatments using a state space model and then compared to infer differential edges/interactions. DE genes possessing differential edges were mapped to biological pathways in databases such as KEGG pathways. Results Using the DNs approach, we analyzed a time-series Escherichia coli live cell gene expression dataset consisting of 4 treatments (control, 10, 100, 1000 mg/L naphthenic acids, NAs) and 18 time points. Through comparison of reconstructed networks and construction of differential networks, 80 genes were identified as DE genes with a significant number of differential edges, and 22 KEGG pathways were altered in a concentration-dependent manner. Some of these pathways were perturbed to a degree as high as 70% even at the lowest exposure concentration, implying a high sensitivity of our DNs approach. Conclusions Findings from this proof-of-concept study suggest that our approach has a great potential in providing a novel and sensitive tool for threshold setting in chemical risk assessment. In future work, we plan to analyze more time-series datasets with a full spectrum of concentrations and sufficient replications per treatment. The pathway alteration-derived thresholds will also be compared with those derived from apical endpoints such as cell growth rate.
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460
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Hermsen SA, Pronk TE, van den Brandhof EJ, van der Ven LT, Piersma AH. Transcriptomic analysis in the developing zebrafish embryo after compound exposure: Individual gene expression and pathway regulation. Toxicol Appl Pharmacol 2013; 272:161-71. [DOI: 10.1016/j.taap.2013.05.037] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Revised: 05/01/2013] [Accepted: 05/22/2013] [Indexed: 11/15/2022]
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461
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Attene-Ramos MS, Huang R, Sakamuru S, Witt KL, Beeson GC, Shou L, Schnellmann RG, Beeson CC, Tice RR, Austin CP, Xia M. Systematic study of mitochondrial toxicity of environmental chemicals using quantitative high throughput screening. Chem Res Toxicol 2013; 26:1323-32. [PMID: 23895456 DOI: 10.1021/tx4001754] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A goal of the Tox21 program is to transit toxicity testing from traditional in vivo models to in vitro assays that assess how chemicals affect cellular responses and toxicity pathways. A critical contribution of the NIH Chemical Genomics center (NCGC) to the Tox21 program is the implementation of a quantitative high throughput screening (qHTS) approach, using cell- and biochemical-based assays to generate toxicological profiles for thousands of environmental compounds. Here, we evaluated the effect of chemical compounds on mitochondrial membrane potential in HepG2 cells by screening a library of 1,408 compounds provided by the National Toxicology Program (NTP) in a qHTS platform. Compounds were screened over 14 concentrations, and results showed that 91 and 88 compounds disrupted mitochondrial membrane potential after treatment for 1 or 5 h, respectively. Seventy-six compounds active at both time points were clustered by structural similarity, producing 11 clusters and 23 singletons. Thirty-eight compounds covering most of the active chemical space were more extensively evaluated. Thirty-six of the 38 compounds were confirmed to disrupt mitochondrial membrane potential using a fluorescence plate reader, and 35 were confirmed using a high content imaging approach. Among the 38 compounds, 4 and 6 induced LDH release, a measure of cytotoxicity, at 1 or 5 h, respectively. Compounds were further assessed for mechanism of action (MOA) by measuring changes in oxygen consumption rate, which enabled the identification of 20 compounds as uncouplers. This comprehensive approach allows for the evaluation of thousands of environmental chemicals for mitochondrial toxicity and identification of possible MOAs.
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Affiliation(s)
- Matias S Attene-Ramos
- National Center for Advancing Translational Sciences, National Institutes of Health , Bethesda, Maryland 20892, United States
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462
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Attene-Ramos MS, Miller N, Huang R, Michael S, Itkin M, Kavlock RJ, Austin CP, Shinn P, Simeonov A, Tice RR, Xia M. The Tox21 robotic platform for the assessment of environmental chemicals--from vision to reality. Drug Discov Today 2013; 18:716-23. [PMID: 23732176 PMCID: PMC3771082 DOI: 10.1016/j.drudis.2013.05.015] [Citation(s) in RCA: 158] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 04/05/2013] [Accepted: 05/23/2013] [Indexed: 01/28/2023]
Abstract
Since its establishment in 2008, the US Tox21 inter-agency collaboration has made great progress in developing and evaluating cellular models for the evaluation of environmental chemicals as a proof of principle. Currently, the program has entered its production phase (Tox21 Phase II) focusing initially on the areas of modulation of nuclear receptors and stress response pathways. During Tox21 Phase II, the set of chemicals to be tested has been expanded to nearly 10,000 (10K) compounds and a fully automated screening platform has been implemented. The Tox21 robotic system combined with informatics efforts is capable of screening and profiling the collection of 10K environmental chemicals in triplicate in a week. In this article, we describe the Tox21 screening process, compound library preparation, data processing, and robotic system validation.
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Affiliation(s)
- Matias S Attene-Ramos
- NIH Chemical Genomics Center, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD 20850, USA
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463
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Allard P, Kleinstreuer NC, Knudsen TB, Colaiácovo MP. A C. elegans screening platform for the rapid assessment of chemical disruption of germline function. ENVIRONMENTAL HEALTH PERSPECTIVES 2013; 121:717-24. [PMID: 23603051 PMCID: PMC3672921 DOI: 10.1289/ehp.1206301] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Accepted: 04/18/2013] [Indexed: 05/19/2023]
Abstract
BACKGROUND Despite the developmental impact of chromosome segregation errors, we lack the tools to assess environmental effects on the integrity of the germline in animals. OBJECTIVES We developed an assay in Caenorhabditis elegans that fluorescently marks aneuploid embryos after chemical exposure. METHODS We qualified the predictive value of the assay against chemotherapeutic agents as well as environmental compounds from the ToxCast Phase I library by comparing results from the C. elegans assay with the comprehensive mammalian in vivo end point data from the ToxRef database. RESULTS The assay was highly predictive of mammalian reproductive toxicities, with a 69% maximum balanced accuracy. We confirmed the effect of select compounds on germline integrity by monitoring germline apoptosis and meiotic progression. CONCLUSIONS This C. elegans assay provides a comprehensive strategy for assessing environmental effects on germline function.
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Affiliation(s)
- Patrick Allard
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115 , USA
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464
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Xie HQ, Xu HM, Fu HL, Hu Q, Tian WJ, Pei XH, Zhao B. AhR-mediated effects of dioxin on neuronal acetylcholinesterase expression in vitro. ENVIRONMENTAL HEALTH PERSPECTIVES 2013; 121:613-8. [PMID: 23426015 PMCID: PMC3673198 DOI: 10.1289/ehp.1206066] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Accepted: 02/19/2013] [Indexed: 05/18/2023]
Abstract
BACKGROUND Deficits in cognitive functioning have been reported in humans exposed to dioxins and dioxin-like compounds. Evidence suggests that dioxins induce cholinergic dysfunction mediated by hypothyroidism. However, little is known about direct effects of dioxins on the cholinergic system. OBJECTIVES We investigated the action of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on acetylcholinesterase (AChE), a key enzyme in cholinergic neurotransmission. METHODS We used SK-N-SH human-derived neuronal cells to evaluate the effect of dioxin exposure on AChE. RESULTS We consistently found a significant decrease in enzymatic activity of AChE in cultured neurons treated with TCDD. We also found that, unlike organophosphate pesticides that directly act on the catalytic center of AChE, the suppressive effect of dioxin was through transcriptional regulation. The addition of CH223191, an inhibitor of the aryl hydrocarbon receptor (AhR)-dependent pathway, counteracted the TCDD-induced suppression of AChE, suggesting involvement of the AhR-dependent pathway. The existence of putative dioxin-responsive element (DRE) consensus sequences in the human ACHE promoter region further supported this hypothesis. Consistent with the absence of DRE elements in mouse or rat ACHE promoter regions, suppression of AChE by TCDD did not occur in rat neuronal cells, indicating a potential species-specific effect. CONCLUSIONS In SK-N-SH cells, dioxin suppressed the activity of neuronal AChE via AhR-mediated transcriptional down-regulation. This is the first study to report direct interference by dioxin with the cholinergic neurotransmission system.
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Affiliation(s)
- Heidi Qunhui Xie
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
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465
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Péry ARR, Brochot C, Zeman FA, Mombelli E, Desmots S, Pavan M, Fioravanzo E, Zaldívar JM. Prediction of dose-hepatotoxic response in humans based on toxicokinetic/toxicodynamic modeling with or without in vivo data: a case study with acetaminophen. Toxicol Lett 2013; 220:26-34. [PMID: 23566899 DOI: 10.1016/j.toxlet.2013.03.032] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 03/23/2013] [Accepted: 03/25/2013] [Indexed: 02/04/2023]
Abstract
In the present legislations, the use of methods alternative to animal testing is explicitly encouraged, to use animal testing only 'as a last resort' or to ban it. The use of alternative methods to replace kinetics or repeated dose in vivo tests is a challenging issue. We propose here a strategy based on in vitro tests and QSAR (Quantitative Structure Activity Relationship) models to calibrate a dose-response model predicting hepatotoxicity. The dose response consists in calibrating and coupling a PBPK (physiologically-based pharmacokinetic) model with a toxicodynamic model for cell viability. We applied our strategy to acetaminophen and compared three different ways to calibrate the PBPK model: only with in vitro and in silico methods, using rat data or using all available data including data on humans. Some estimates of kinetic parameters differed substantially among the three calibration processes, but, at the end, the three models were quite comparable in terms of liver toxicity predictions and close to the usual range of human overdose. For the model based on alternative methods, the good adequation with the two other models resulted from an overestimated renal elimination rate which compensated for the underestimation of the metabolism rate. Our study points out that toxicokinetics/toxicodynamics approaches, based on alternative methods and modelling only, can predict in vivo liver toxicity with accuracy comparable to in vivo methods.
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Affiliation(s)
- Alexandre R R Péry
- Unité « Modèles pour l'écotoxicologie et la toxicologie » (METO), INERIS, Parc Alata BP2, 60550 Verneuil-en-Halatte, France.
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466
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Hectors TLM, Vanparys C, Pereira-Fernandes A, Martens GA, Blust R. Evaluation of the INS-1 832/13 cell line as a beta-cell based screening system to assess pollutant effects on beta-cell function. PLoS One 2013; 8:e60030. [PMID: 23555872 PMCID: PMC3605429 DOI: 10.1371/journal.pone.0060030] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 02/22/2013] [Indexed: 01/15/2023] Open
Abstract
Environmental pollutants have recently emerged as potential risk factors for metabolic diseases, urging systematic investigation of pollutant effects on metabolic disease processes. To enable risk assessment of these so-called metabolic disruptors the use of stable, robust and well-defined cell based screening systems has recently been encouraged. Since beta-cell (dys)functionality is central in diabetes pathophysiology, the need to develop beta-cell based pollutant screening systems is evident. In this context, the present research evaluated the strengths and weaknesses of the INS-1 832/13 pancreatic beta-cell line as diabetogenic pollutant screening system with a focus on beta-cell function. After optimization of exposure conditions, positive (exendin-4, glibenclamide) and negative (diazoxide) control compounds for acute insulin secretion responses were tested and those with the most profound effects were selected to allow potency estimations and ranking of pollutants. This was followed by a first explorative screening of acute bisphenol A and bis(2-ethylhexyl)phthalate effects. The same approach was applied for chronic exposures, focusing primarily on evaluation of acknowledged chronic stimulators (diazoxide, T0901317, exendin-4) or inhibitors (glibenclamide) of insulin secretion responses to select the most responsive ones for use as control compounds in a chronic pollutant testing framework. Our results showed that INS-1 832/13 cells responded conform previous observations regarding acute effects of control compounds on insulin secretion, while bisphenol A and bis(2-ethylhexyl)phthalate had limited acute effects. Furthermore, chronic exposure to known beta-cell reactive compounds resulted in deviating insulin secretion and insulin content profiles compared to previous reports. In conclusion, this INS-1 subclone appears to lack certain characteristics needed to respond appropriately to acute pollutant exposure or long term exposure to known beta-cell reactive compounds and thus seems to be, in our setting, inadequate as a diabetogenic pollutant screening system.
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Affiliation(s)
- Tine L M Hectors
- Systemic Physiological and Ecotoxicological Research, Department of Biology, University of Antwerp, Antwerp, Belgium.
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467
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Evaluation of an alternative in vitro test battery for detecting reproductive toxicants. Reprod Toxicol 2013; 38:53-64. [PMID: 23511061 DOI: 10.1016/j.reprotox.2013.03.002] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 03/06/2013] [Accepted: 03/09/2013] [Indexed: 01/01/2023]
Abstract
The application of alternative methods in developmental and reproductive toxicology is challenging in view of the complexity of mechanisms involved. A battery of complementary test systems may provide a better prediction of developmental and reproductive toxicity than single assays. We tested twelve compounds with varying mechanisms of toxic action in an assay battery including 24 CALUX transcriptional activation assays, mouse cardiac embryonic stem cell test, ReProGlo assay, zebrafish embryotoxicity assay, and two CYP17 and two CYP19 activity assays. The battery correctly detected 11/12 compounds tested, with one false negative occurring, which could be explained by the absence of the specific mechanism of action of this compound in the battery. Toxicokinetic modeling revealed that toxic concentrations were in the range expected from in vivo reproductive toxicity data. This study illustrates added value of combining assays that contain complementary biological processes and mechanisms, increasing predictive value of the battery over individual assays.
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468
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Sauer UG, Vogel S, Hess A, Kolle SN, Ma-Hock L, van Ravenzwaay B, Landsiedel R. In vivo–in vitro comparison of acute respiratory tract toxicity using human 3D airway epithelial models and human A549 and murine 3T3 monolayer cell systems. Toxicol In Vitro 2013; 27:174-90. [DOI: 10.1016/j.tiv.2012.10.007] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 10/04/2012] [Accepted: 10/11/2012] [Indexed: 10/27/2022]
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469
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Kohonen P, Benfenati E, Bower D, Ceder R, Crump M, Cross K, Grafström RC, Healy L, Helma C, Jeliazkova N, Jeliazkov V, Maggioni S, Miller S, Myatt G, Rautenberg M, Stacey G, Willighagen E, Wiseman J, Hardy B. The ToxBank Data Warehouse: Supporting the Replacement of In Vivo Repeated Dose Systemic Toxicity Testing. Mol Inform 2013; 32:47-63. [PMID: 27481023 DOI: 10.1002/minf.201200114] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Accepted: 11/27/2012] [Indexed: 12/12/2022]
Abstract
The aim of the SEURAT-1 (Safety Evaluation Ultimately Replacing Animal Testing-1) research cluster, comprised of seven EU FP7 Health projects co-financed by Cosmetics Europe, is to generate a proof-of-concept to show how the latest technologies, systems toxicology and toxicogenomics can be combined to deliver a test replacement for repeated dose systemic toxicity testing on animals. The SEURAT-1 strategy is to adopt a mode-of-action framework to describe repeated dose toxicity, combining in vitro and in silico methods to derive predictions of in vivo toxicity responses. ToxBank is the cross-cluster infrastructure project whose activities include the development of a data warehouse to provide a web-accessible shared repository of research data and protocols, a physical compounds repository, reference or "gold compounds" for use across the cluster (available via wiki.toxbank.net), and a reference resource for biomaterials. Core technologies used in the data warehouse include the ISA-Tab universal data exchange format, REpresentational State Transfer (REST) web services, the W3C Resource Description Framework (RDF) and the OpenTox standards. We describe the design of the data warehouse based on cluster requirements, the implementation based on open standards, and finally the underlying concepts and initial results of a data analysis utilizing public data related to the gold compounds.
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Affiliation(s)
| | | | | | | | | | | | | | - Lyn Healy
- National Institute for Biological Standards and Control, Potters Bar, UK
| | | | | | | | - Silvia Maggioni
- Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | | | | | | | - Glyn Stacey
- National Institute for Biological Standards and Control, Potters Bar, UK
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470
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Williams DP, Shipley R, Ellis MJ, Webb S, Ward J, Gardner I, Creton S. Novel in vitro and mathematical models for the prediction of chemical toxicity. Toxicol Res (Camb) 2013; 2:40-59. [PMID: 26966512 PMCID: PMC4765367 DOI: 10.1039/c2tx20031g] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Accepted: 08/24/2012] [Indexed: 01/17/2023] Open
Abstract
The focus of much scientific and medical research is directed towards understanding the disease process and defining therapeutic intervention strategies. The scientific basis of drug safety is very complex and currently remains poorly understood, despite the fact that adverse drug reactions (ADRs) are a major health concern and a serious impediment to development of new medicines. Toxicity issues account for ∼21% drug attrition during drug development and safety testing strategies require considerable animal use. Mechanistic relationships between drug plasma levels and molecular/cellular events that culminate in whole organ toxicity underpins development of novel safety assessment strategies. Current in vitro test systems are poorly predictive of toxicity of chemicals entering the systemic circulation, particularly to the liver. Such systems fall short because of (1) the physiological gap between cells currently used and human hepatocytes existing in their native state, (2) the lack of physiological integration with other cells/systems within organs, required to amplify the initial toxicological lesion into overt toxicity, (3) the inability to assess how low level cell damage induced by chemicals may develop into overt organ toxicity in a minority of patients, (4) lack of consideration of systemic effects. Reproduction of centrilobular and periportal hepatocyte phenotypes in in vitro culture is crucial for sensitive detection of cellular stress. Hepatocyte metabolism/phenotype is dependent on cell position along the liver lobule, with corresponding differences in exposure to substrate, oxygen and hormone gradients. Application of bioartificial liver (BAL) technology can encompass in vitro predictive toxicity testing with enhanced sensitivity and improved mechanistic understanding. Combining this technology with mechanistic mathematical models describing intracellular metabolism, fluid-flow, substrate, hormone and nutrient distribution provides the opportunity to design the BAL specifically to mimic the in vivo scenario. Such mathematical models enable theoretical hypothesis testing, will inform the design of in vitro experiments, and will enable both refinement and reduction of in vivo animal trials. In this way, development of novel mathematical modelling tools will help to focus and direct in vitro and in vivo research, and can be used as a framework for other areas of drug safety science.
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Affiliation(s)
- Dominic P Williams
- MRC Centre for Drug Safety Science , Department of Molecular and Clinical Pharmacology , Institute of Translational Medicine , The University of Liverpool , Sherrington Building , Ashton St. , Liverpool , L69 3GE , UK . ; ; Tel: +44 (0)151 794 5791
| | - Rebecca Shipley
- Department of Mechanical Engineering , University College London , Torrington Place , London WC1E 7JE , UK
| | - Marianne J Ellis
- Department of Chemical Engineering , University of Bath , Claverton Down , Bath , BA2 7AY , UK
| | - Steve Webb
- Department of Mathematics and Statistics , University of Strathclyde , Livingstone Tower , 26 Richmond Street , Glasgow , G1 1XH , UK
| | - John Ward
- School of Mathematical Sciences , Loughborough University , Loughborough , LE11 3TU , UK
| | - Iain Gardner
- Simcyp Limited , Blades Enterprise Centre , John Street , Sheffield S2 4SU , UK
| | - Stuart Creton
- NC3Rs Gibbs Building , 215 Euston Road , London , NW1 2BE , UK
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471
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Wolansky MJ, Tornero-Velez R. Critical consideration of the multiplicity of experimental and organismic determinants of pyrethroid neurotoxicity: a proof of concept. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2013; 16:453-490. [PMID: 24298913 DOI: 10.1080/10937404.2013.853607] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Pyrethroids (PYR) are pesticides with high insecticidal activity that may disrupt neuronal excitability in target and nontarget species. The accumulated evidence consistently showed that this neurophysiologic action is followed by alterations in motor, sensorimotor, neuromuscular, and thermoregulatory responses. Nevertheless, there are some equivocal results regarding the potency of PYR in lab animals. The estimation of potency is an important step in pesticide chemical risk assessment. In order to identify the variables influencing neurobehavioral findings across PYR studies, evidence on experimental and organismic determinants of acute PYR-induced neurotoxicity was reviewed in rodents. A comprehensive analysis of these studies was conducted focusing on test material and dosing conditions, testing conditions, animal models, and other determinants such as testing room temperature. Variations in the severity of the neurotoxicity, under lab-controlled conditions, was explained based upon factors including influence of animal species and age, test material features such as chemical structure and stereochemistry, and dosing conditions such as vehicle, route of exposure, and dose volume. If not controlled, the interplay of these factors may lead to large variance in potency estimation. This review examined the scope of acute toxicological data required to determine the safety of pesticide products, and factors and covariates that need to be controlled in order to ensure that predictivity and precaution are balanced in a risk assessment process within a reasonable time-frame, using acute PYR-induced neurotoxicity in rodents as an exemplar.
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Affiliation(s)
- M J Wolansky
- a Laboratorio de Toxicología de Mezclas Químicas, Instituto de Investigación IQUIBICEN, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Departamento Química Biológica, Facultad de Ciencias Exactas y Naturales , Universidad de Buenos Aires, Ciudad Universitaria UBA, Ciudad Autónoma de Buenos Aires , Argentina
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472
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Burns CJ, McIntosh LJ, Mink PJ, Jurek AM, Li AA. Pesticide exposure and neurodevelopmental outcomes: review of the epidemiologic and animal studies. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2013; 16:127-283. [PMID: 23777200 PMCID: PMC3705499 DOI: 10.1080/10937404.2013.783383] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Assessment of whether pesticide exposure is associated with neurodevelopmental outcomes in children can best be addressed with a systematic review of both the human and animal peer-reviewed literature. This review analyzed epidemiologic studies testing the hypothesis that exposure to pesticides during pregnancy and/or early childhood is associated with neurodevelopmental outcomes in children. Studies that directly queried pesticide exposure (e.g., via questionnaire or interview) or measured pesticide or metabolite levels in biological specimens from study participants (e.g., blood, urine, etc.) or their immediate environment (e.g., personal air monitoring, home dust samples, etc.) were eligible for inclusion. Consistency, strength of association, and dose response were key elements of the framework utilized for evaluating epidemiologic studies. As a whole, the epidemiologic studies did not strongly implicate any particular pesticide as being causally related to adverse neurodevelopmental outcomes in infants and children. A few associations were unique for a health outcome and specific pesticide, and alternative hypotheses could not be ruled out. Our survey of the in vivo peer-reviewed published mammalian literature focused on effects of the specific active ingredient of pesticides on functional neurodevelopmental endpoints (i.e., behavior, neuropharmacology and neuropathology). In most cases, effects were noted at dose levels within the same order of magnitude or higher compared to the point of departure used for chronic risk assessments in the United States. Thus, although the published animal studies may have characterized potential neurodevelopmental outcomes using endpoints not required by guideline studies, the effects were generally observed at or above effect levels measured in repeated-dose toxicology studies submitted to the U.S. Environmental Protection Agency (EPA). Suggestions for improved exposure assessment in epidemiology studies and more effective and tiered approaches in animal testing are discussed.
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Affiliation(s)
| | | | - Pamela J. Mink
- Allina Health Center for Healthcare Research & Innovation, Minneapolis, Minnesota, USA
| | - Anne M. Jurek
- Allina Health Center for Healthcare Research & Innovation, Minneapolis, Minnesota, USA
| | - Abby A. Li
- Exponent, Inc., Menlo Park, California, USA
- Address correspondence to Abby A. Li, PhD, Attn: Rebecca Edwards, Exponent, Inc., Health Sciences Group, 149 Commonwealth Drive, Menlo Park, CA 94025-1133, USA. E-mail:
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473
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Hoelting L, Scheinhardt B, Bondarenko O, Schildknecht S, Kapitza M, Tanavde V, Tan B, Lee QY, Mecking S, Leist M, Kadereit S. A 3-dimensional human embryonic stem cell (hESC)-derived model to detect developmental neurotoxicity of nanoparticles. Arch Toxicol 2012. [PMID: 23203475 PMCID: PMC3604581 DOI: 10.1007/s00204-012-0984-2] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Nanoparticles (NPs) have been shown to accumulate in organs, cross the blood-brain barrier and placenta, and have the potential to elicit developmental neurotoxicity (DNT). Here, we developed a human embryonic stem cell (hESC)-derived 3-dimensional (3-D) in vitro model that allows for testing of potential developmental neurotoxicants. Early central nervous system PAX6(+) precursor cells were generated from hESCs and differentiated further within 3-D structures. The 3-D model was characterized for neural marker expression revealing robust differentiation toward neuronal precursor cells, and gene expression profiling suggested a predominantly forebrain-like development. Altered neural gene expression due to exposure to non-cytotoxic concentrations of the known developmental neurotoxicant, methylmercury, indicated that the 3-D model could detect DNT. To test for specific toxicity of NPs, chemically inert polyethylene NPs (PE-NPs) were chosen. They penetrated deep into the 3-D structures and impacted gene expression at non-cytotoxic concentrations. NOTCH pathway genes such as HES5 and NOTCH1 were reduced in expression, as well as downstream neuronal precursor genes such as NEUROD1 and ASCL1. FOXG1, a patterning marker, was also reduced. As loss of function of these genes results in severe nervous system impairments in mice, our data suggest that the 3-D hESC-derived model could be used to test for Nano-DNT.
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Affiliation(s)
- Lisa Hoelting
- Department of Biology, University of Konstanz, Universitaetsstrasse 10, 78457 Konstanz, Germany
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474
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Toxicogenomics for transcription factor-governed molecular pathways: moving on to roles beyond classification and prediction. Arch Toxicol 2012. [DOI: 10.1007/s00204-012-0980-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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475
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476
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Jennings P. Stress response pathways, toxicity pathways and adverse outcome pathways. Arch Toxicol 2012; 87:13-4. [PMID: 23149676 DOI: 10.1007/s00204-012-0974-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 10/30/2012] [Indexed: 11/25/2022]
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477
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Abstract
Toxicology is and will be heavily influenced by advances in many scientific disciplines. For toxicologic pathology, particularly relevant are the increasing array of molecular methods providing deeper insights into toxicity pathways, in vivo imaging techniques visualizing toxicodynamics and more powerful computers anticipated to allow (partly) automated morphological diagnoses. It appears unlikely that, in a foreseeable future, animal studies can be replaced by in silico and in vitro studies or longer term in vivo studies by investigations of biomarkers including toxicogenomics of shorter term studies, though the importance of such approaches will continue to increase. In addition to changes based on scientific progress, the work of toxicopathologists is and will be affected by social and financial factors, among them stagnating budgets, globalization, and outsourcing. The number of toxicopathologists in North America, Europe, and the Far East is not expected to grow. Many toxicopathologists will likely spend less time at the microscope but will be more heavily involved in early research activities, imaging, and as generalists with a broad biological understanding in evaluation and management of toxicity. Toxicologic pathology will remain important and is indispensable for validation of new methods, quality assurance of established methods, and for areas without good alternative methods.
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478
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Tralau T, Riebeling C, Pirow R, Oelgeschläger M, Seiler A, Liebsch M, Luch A. Wind of change challenges toxicological regulators. ENVIRONMENTAL HEALTH PERSPECTIVES 2012; 120:1489-94. [PMID: 22871563 PMCID: PMC3556610 DOI: 10.1289/ehp.1104782] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Accepted: 08/07/2012] [Indexed: 05/09/2023]
Abstract
BACKGROUND In biomedical research, the past two decades have seen the advent of in vitro model systems based on stem cells, humanized cell lines, and engineered organotypic tissues, as well as numerous cellular assays based on primarily established tumor-derived cell lines and their genetically modified derivatives. OBJECTIVE There are high hopes that these systems might replace the need for animal testing in regulatory toxicology. However, despite increasing pressure in recent years to reduce animal testing, regulators are still reluctant to adopt in vitro approaches on a large scale. It thus seems appropriate to consider how we could realistically perform regulatory toxicity testing using in vitro assays only. DISCUSSION AND CONCLUSION Here, we suggest an in vitro-only approach for regulatory testing that will benefit consumers, industry, and regulators alike.
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Affiliation(s)
- Tewes Tralau
- German Federal Institute for Risk Assessment (BfR), Center for Alternative Methods to Animal Experiments (ZEBET), Berlin, Germany
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479
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Abstract
High-potency or artificial sweeteners have historically been considered inert compounds without physiological consequences other than taste sensations. However, recent data suggest that some of these sweeteners have biological effects that may impact human health. Furthermore, there are significant gaps in our current knowledge of the pharmacokinetics of these sweeteners, their potential for "sweetener-drug interactions" and their impact on appetite and body weight regulation. Nine research needs are described that address some of the major unknown issues associated with ingestion of high-potency sweeteners.
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480
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Quantitative risk assessment methods for cancer and noncancer effects. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2012. [PMID: 22974743 DOI: 10.1016/b978-0-12-415813-9.00009-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Human health risk assessments have evolved from the more qualitative approaches to more quantitative approaches in the past decade. This has been facilitated by the improvement in computer hardware and software capability and novel computational approaches being slowly recognized by regulatory agencies. These events have helped reduce the reliance on experimental animals as well as better utilization of published animal toxicology data in deriving quantitative toxicity indices that may be useful for risk management purposes. This chapter briefly describes some of the approaches as described in the guidance documents from several of the regulatory agencies as it pertains to hazard identification and dose-response assessment of a chemical. These approaches are contrasted with more novel computational approaches that provide a better grasp of the uncertainty often associated with chemical risk assessments.
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481
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Gao C, Weisman D, Gou N, Ilyin V, Gu AZ. Analyzing high dimensional toxicogenomic data using consensus clustering. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:8413-8421. [PMID: 22703334 DOI: 10.1021/es3000454] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Rapid development of high-throughput toxicogenomics technologies has created new approaches to screen environmental samples for mechanistic toxicity assessment. However, challenges remain in the analysis, especially clustering of the resulting high-dimensional data. Because of the lack of commonly accepted validation methods, it is difficult to compare clustering results between studies or to identify the key experimental or data features that impact the clustering results. We applied consensus clustering (CC), an approach that clusters the input data repeatedly through iterative resampling, and identifies frequently occurring high-confidence clusters. We used CC to analyze a set of high dimensional transcriptomics data with temporal resolution, which were generated using our E. coli whole-cell array system for a diverse variety of toxicants at different dose concentrations. The CC analysis allowed us to evaluate the clustering results' robustness and sensitivity against a number of conditions that represent the common variations in high-throughput experiments, including noisy data, subsets of treatments, subsets of reporter genes, and subsets of time points. We demonstrated the value of utilizing rich time-series data and underscored the importance of careful selection of sampling times for a given experimental system. The results also indicated that temporal data compression using our proposed Transcriptional Effect Level Index (TELI) concept followed by CC largely conserved the cluster resolution. We also found that for our cellular stress response ensemble-based high-throughput transcriptomics assay platform, the size and composition of the reporter gene set are critical factors that affect the resulting coherency of clusters. Taken together, these results demonstrated that more robust consensus clustering such as CC may be valuable in analyzing high-dimensional toxicogenomic data sets.
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Affiliation(s)
- Ce Gao
- Department of Civil and Environmental Engineering, Northeastern University, Boston, Massachusetts 02115, USA
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482
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Tralau T, Luch A. Drug-mediated toxicity: illuminating the ‘bad’ in the test tube by means of cellular assays? Trends Pharmacol Sci 2012; 33:353-64. [DOI: 10.1016/j.tips.2012.03.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 03/12/2012] [Accepted: 03/28/2012] [Indexed: 12/19/2022]
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483
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LeCluyse EL, Witek RP, Andersen ME, Powers MJ. Organotypic liver culture models: meeting current challenges in toxicity testing. Crit Rev Toxicol 2012; 42:501-48. [PMID: 22582993 PMCID: PMC3423873 DOI: 10.3109/10408444.2012.682115] [Citation(s) in RCA: 239] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2011] [Revised: 03/26/2012] [Accepted: 03/30/2012] [Indexed: 02/07/2023]
Abstract
Prediction of chemical-induced hepatotoxicity in humans from in vitro data continues to be a significant challenge for the pharmaceutical and chemical industries. Generally, conventional in vitro hepatic model systems (i.e. 2-D static monocultures of primary or immortalized hepatocytes) are limited by their inability to maintain histotypic and phenotypic characteristics over time in culture, including stable expression of clearance and bioactivation pathways, as well as complex adaptive responses to chemical exposure. These systems are less than ideal for longer-term toxicity evaluations and elucidation of key cellular and molecular events involved in primary and secondary adaptation to chemical exposure, or for identification of important mediators of inflammation, proliferation and apoptosis. Progress in implementing a more effective strategy for in vitro-in vivo extrapolation and human risk assessment depends on significant advances in tissue culture technology and increasing their level of biological complexity. This article describes the current and ongoing need for more relevant, organotypic in vitro surrogate systems of human liver and recent efforts to recreate the multicellular architecture and hemodynamic properties of the liver using novel culture platforms. As these systems become more widely used for chemical and drug toxicity testing, there will be a corresponding need to establish standardized testing conditions, endpoint analyses and acceptance criteria. In the future, a balanced approach between sample throughput and biological relevance should provide better in vitro tools that are complementary with animal testing and assist in conducting more predictive human risk assessment.
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Affiliation(s)
- Edward L LeCluyse
- The Institute for Chemical Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, NC, USA.
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484
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Cohen J, Deloid G, Pyrgiotakis G, Demokritou P. Interactions of engineered nanomaterials in physiological media and implications for in vitro dosimetry. Nanotoxicology 2012; 7:417-31. [PMID: 22393878 DOI: 10.3109/17435390.2012.666576] [Citation(s) in RCA: 168] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
In vitro toxicity assays are efficient and inexpensive tools for screening the increasing number of engineered nanomaterials (ENMs) entering the consumer market. However, the data produced by in vitro studies often vary substantially among different studies and from in vivo data. In part, these discrepancies may be attributable to lack of standardisation in dispersion protocols and inadequate characterisation of particle-media interactions which may affect the particle kinetics and the dose delivered to cells. In this study, a novel approach for preparation of monodisperse, stabilised liquid suspensions is presented and coupled with a numerical model which estimates delivered dose values. Empirically derived material- and media-specific functions are presented for each media-ENM system that can be used to convert administered doses to delivered doses. The interactions of ENMs with a variety of physiologic media were investigated and the importance of this approach was demonstrated by in vitro cytotoxicity assays using THP-1 macrophages.
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Affiliation(s)
- Joel Cohen
- Department of Environmental Health, Center for Nanotechnology and Nanotoxicology, Harvard School of Public Health, Boston, MA, USA
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485
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Xing X, Liu C, Tang S, Li D, Chen L, Pang Y, Wang Q, Zhang B, Zeng X, Chen W, Xiao Y. DNA repair gene deficiency does not predispose human bronchial epithelial cells to benzo(a)pyrene-induced cell transformation. Toxicol In Vitro 2012; 26:579-84. [PMID: 22382310 DOI: 10.1016/j.tiv.2012.02.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Revised: 01/20/2012] [Accepted: 02/10/2012] [Indexed: 11/18/2022]
Abstract
The development of cost and time-efficient in vitro assays to predict carcinogenicity of chemicals has become a very important direction for toxicological research. In this study, we generated a series of human bronchial epithelial (HBE) cells defect in DNA repair gene excision repair cross-completion 1 (ERCC1), excision repair cross-completion 2 (ERCC2), ataxia-telangiectasia mutated (ATM) and mutS homolog 2 (MSH2), respectively. The inhibition of gene expression was verified by detection of mRNA and protein levels of respective genes. The suppression of these DNA repair genes has no impact on cell proliferation or cell transformation. Although we found that the transgenic HBE cells were more sensitive in benzo(a)pyrene (BaP)-induced DNA damages measured by cytokinesis-block micronucleus (CBMN) assay and comet assay, we failed to observe enhanced effects on induction of cell transformation. HBE cells defect in DNA repair pathways did not exhibit malignantly transformed phenotype up to 20 weeks of BaP treatment, indicating that the deficiency of ERCC1, ERCC2, ATM, or MSH2 alone did not shorten the latency of cell transformation. In contrast, we found that HBE cells expressing H-Ras or c-Myc were transformed 8 or 12 weeks after BaP treatment. These findings demonstrate that silencing of a single DNA repair gene does not confer cells susceptible to chemical-induced cell transformation.
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Affiliation(s)
- Xiumei Xing
- Department of Toxicology, Faculty of Preventive Medicine, Guangdong Provincial Key Laboratory of Food, Nutrition and Health, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
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486
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Andersen ME, Clewell HJ, Carmichael PL, Boekelheide K. Can case study approaches speed implementation of the NRC report: "toxicity testing in the 21st century: a vision and a strategy?". ALTEX-ALTERNATIVES TO ANIMAL EXPERIMENTATION 2012; 28:175-82. [PMID: 21993955 DOI: 10.14573/altex.2011.3.175] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The 2007 report "Toxicity Testing in the 21st Century: A Vision and a Strategy" argued for a change in toxicity testing for environmental agents and discussed federal funding mechanisms that could be used to support this transformation within the USA. The new approach would test for in vitro perturbations of toxicity pathways using human cells with high-throughput testing platforms. The NRC report proposed a deliberate timeline, spanning about 20 years, to implement a wholesale replacement of current in-life toxicity test approaches focused on apical responses with in vitro assays. One approach to accelerating implementation is to focus on well-studied prototype compounds with known toxicity pathway targets. Through a series of carefully executed case studies with four or five pathway prototypes, the various steps required for implementation of an in vitro toxicity pathway approach to risk assessment could be developed and refined. In this article, we discuss alternative approaches for implementation and also outline advantages of a case study approach and the manner in which the case studies could be pursued using current methodologies. A case study approach would be complementary to recently proposed efforts to map the human toxome, while representing a significant extension toward more formal risk assessment compared to the profiling and prioritization approaches inherent in programs such as the EPA's ToxCast effort.
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Affiliation(s)
- Melvin E Andersen
- The Institute for Chemical Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, NC 27709-2137, USA.
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487
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Liebsch M, Grune B, Seiler A, Butzke D, Oelgeschläger M, Pirow R, Adler S, Riebeling C, Luch A. Alternatives to animal testing: current status and future perspectives. Arch Toxicol 2011; 85:841-58. [PMID: 21607681 PMCID: PMC3149673 DOI: 10.1007/s00204-011-0718-x] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
On the occasion of the 20th anniversary of the Center for Alternative Methods to Animal Experiments (ZEBET), an international symposium was held at the German Federal Institute for Risk Assessment (BfR) in Berlin. At the same time, this symposium was meant to celebrate the 50th anniversary of the publication of the book “The Principles of Humane Experimental Technique” by Russell and Burch in 1959 in which the 3Rs principle (that is, Replacement, Reduction, and Refinement) has been coined and introduced to foster the development of alternative methods to animal testing. Another topic addressed by the symposium was the new vision on “Toxicology in the twenty-first Century”, as proposed by the US-National Research Council, which aims at using human cells and tissues for toxicity testing in vitro rather than live animals. An overview of the achievements and current tasks, as well as a vision of the future to be addressed by ZEBET@BfR in the years to come is outlined in the present paper.
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Affiliation(s)
- Manfred Liebsch
- German Federal Institute for Risk Assessment (BfR), Center for Alternative Methods to Animal Experiments—ZEBET, 12277 Berlin, Germany
| | - Barbara Grune
- German Federal Institute for Risk Assessment (BfR), Center for Alternative Methods to Animal Experiments—ZEBET, 12277 Berlin, Germany
| | - Andrea Seiler
- German Federal Institute for Risk Assessment (BfR), Center for Alternative Methods to Animal Experiments—ZEBET, 12277 Berlin, Germany
| | - Daniel Butzke
- German Federal Institute for Risk Assessment (BfR), Center for Alternative Methods to Animal Experiments—ZEBET, 12277 Berlin, Germany
| | - Michael Oelgeschläger
- German Federal Institute for Risk Assessment (BfR), Center for Alternative Methods to Animal Experiments—ZEBET, 12277 Berlin, Germany
| | - Ralph Pirow
- German Federal Institute for Risk Assessment (BfR), Center for Alternative Methods to Animal Experiments—ZEBET, 12277 Berlin, Germany
| | - Sarah Adler
- German Federal Institute for Risk Assessment (BfR), Center for Alternative Methods to Animal Experiments—ZEBET, 12277 Berlin, Germany
| | - Christian Riebeling
- German Federal Institute for Risk Assessment (BfR), Center for Alternative Methods to Animal Experiments—ZEBET, 12277 Berlin, Germany
| | - Andreas Luch
- German Federal Institute for Risk Assessment (BfR), Center for Alternative Methods to Animal Experiments—ZEBET, 12277 Berlin, Germany
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488
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Stephens ML, Barrow C, Andersen ME, Boekelheide K, Carmichael PL, Holsapple MP, Lafranconi M. Accelerating the development of 21st-century toxicology: outcome of a Human Toxicology Project Consortium workshop. Toxicol Sci 2011; 125:327-34. [PMID: 21948868 PMCID: PMC3262850 DOI: 10.1093/toxsci/kfr248] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The U.S. National Research Council (NRC) report on "Toxicity Testing in the 21st century" calls for a fundamental shift in the way that chemicals are tested for human health effects and evaluated in risk assessments. The new approach would move toward in vitro methods, typically using human cells in a high-throughput context. The in vitro methods would be designed to detect significant perturbations to "toxicity pathways," i.e., key biological pathways that, when sufficiently perturbed, lead to adverse health outcomes. To explore progress on the report's implementation, the Human Toxicology Project Consortium hosted a workshop on 9-10 November 2010 in Washington, DC. The Consortium is a coalition of several corporations, a research institute, and a non-governmental organization dedicated to accelerating the implementation of 21st-century Toxicology as aligned with the NRC vision. The goal of the workshop was to identify practical and scientific ways to accelerate implementation of the NRC vision. The workshop format consisted of plenary presentations, breakout group discussions, and concluding commentaries. The program faculty was drawn from industry, academia, government, and public interest organizations. Most presentations summarized ongoing efforts to modernize toxicology testing and approaches, each with some overlap with the NRC vision. In light of these efforts, the workshop identified recommendations for accelerating implementation of the NRC vision, including greater strategic coordination and planning across projects (facilitated by a steering group), the development of projects that test the proof of concept for implementation of the NRC vision, and greater outreach and communication across stakeholder communities.
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Affiliation(s)
- Martin L Stephens
- The Humane Society of United States, Washington, District of Columbia 20037, USA.
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489
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Bhattacharya S, Zhang Q, Carmichael PL, Boekelheide K, Andersen ME. Toxicity testing in the 21 century: defining new risk assessment approaches based on perturbation of intracellular toxicity pathways. PLoS One 2011; 6:e20887. [PMID: 21701582 PMCID: PMC3118802 DOI: 10.1371/journal.pone.0020887] [Citation(s) in RCA: 157] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Accepted: 05/11/2011] [Indexed: 01/15/2023] Open
Abstract
The approaches to quantitatively assessing the health risks of chemical exposure have not changed appreciably in the past 50 to 80 years, the focus remaining on high-dose studies that measure adverse outcomes in homogeneous animal populations. This expensive, low-throughput approach relies on conservative extrapolations to relate animal studies to much lower-dose human exposures and is of questionable relevance to predicting risks to humans at their typical low exposures. It makes little use of a mechanistic understanding of the mode of action by which chemicals perturb biological processes in human cells and tissues. An alternative vision, proposed by the U.S. National Research Council (NRC) report Toxicity Testing in the 21(st) Century: A Vision and a Strategy, called for moving away from traditional high-dose animal studies to an approach based on perturbation of cellular responses using well-designed in vitro assays. Central to this vision are (a) "toxicity pathways" (the innate cellular pathways that may be perturbed by chemicals) and (b) the determination of chemical concentration ranges where those perturbations are likely to be excessive, thereby leading to adverse health effects if present for a prolonged duration in an intact organism. In this paper we briefly review the original NRC report and responses to that report over the past 3 years, and discuss how the change in testing might be achieved in the U.S. and in the European Union (EU). EU initiatives in developing alternatives to animal testing of cosmetic ingredients have run very much in parallel with the NRC report. Moving from current practice to the NRC vision would require using prototype toxicity pathways to develop case studies showing the new vision in action. In this vein, we also discuss how the proposed strategy for toxicity testing might be applied to the toxicity pathways associated with DNA damage and repair.
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Affiliation(s)
- Sudin Bhattacharya
- Program in Chemical Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina, United States of America
| | - Qiang Zhang
- Program in Chemical Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina, United States of America
| | - Paul L. Carmichael
- Safety and Environmental Assurance Centre, Unilever, Colworth Science Park, Sharnbrook, Bedford, United Kingdom
| | - Kim Boekelheide
- Department of Pathology and Laboratory Medicine, Brown University, Providence, Rhode Island, United States of America
| | - Melvin E. Andersen
- Program in Chemical Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina, United States of America
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490
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Adler S, Basketter D, Creton S, Pelkonen O, van Benthem J, Zuang V, Andersen KE, Angers-Loustau A, Aptula A, Bal-Price A, Benfenati E, Bernauer U, Bessems J, Bois FY, Boobis A, Brandon E, Bremer S, Broschard T, Casati S, Coecke S, Corvi R, Cronin M, Daston G, Dekant W, Felter S, Grignard E, Gundert-Remy U, Heinonen T, Kimber I, Kleinjans J, Komulainen H, Kreiling R, Kreysa J, Leite SB, Loizou G, Maxwell G, Mazzatorta P, Munn S, Pfuhler S, Phrakonkham P, Piersma A, Poth A, Prieto P, Repetto G, Rogiers V, Schoeters G, Schwarz M, Serafimova R, Tähti H, Testai E, van Delft J, van Loveren H, Vinken M, Worth A, Zaldivar JM. Alternative (non-animal) methods for cosmetics testing: current status and future prospects-2010. Arch Toxicol 2011; 85:367-485. [PMID: 21533817 DOI: 10.1007/s00204-011-0693-2] [Citation(s) in RCA: 358] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Accepted: 03/03/2011] [Indexed: 01/09/2023]
Abstract
The 7th amendment to the EU Cosmetics Directive prohibits to put animal-tested cosmetics on the market in Europe after 2013. In that context, the European Commission invited stakeholder bodies (industry, non-governmental organisations, EU Member States, and the Commission's Scientific Committee on Consumer Safety) to identify scientific experts in five toxicological areas, i.e. toxicokinetics, repeated dose toxicity, carcinogenicity, skin sensitisation, and reproductive toxicity for which the Directive foresees that the 2013 deadline could be further extended in case alternative and validated methods would not be available in time. The selected experts were asked to analyse the status and prospects of alternative methods and to provide a scientifically sound estimate of the time necessary to achieve full replacement of animal testing. In summary, the experts confirmed that it will take at least another 7-9 years for the replacement of the current in vivo animal tests used for the safety assessment of cosmetic ingredients for skin sensitisation. However, the experts were also of the opinion that alternative methods may be able to give hazard information, i.e. to differentiate between sensitisers and non-sensitisers, ahead of 2017. This would, however, not provide the complete picture of what is a safe exposure because the relative potency of a sensitiser would not be known. For toxicokinetics, the timeframe was 5-7 years to develop the models still lacking to predict lung absorption and renal/biliary excretion, and even longer to integrate the methods to fully replace the animal toxicokinetic models. For the systemic toxicological endpoints of repeated dose toxicity, carcinogenicity and reproductive toxicity, the time horizon for full replacement could not be estimated.
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Affiliation(s)
- Sarah Adler
- Centre for Documentation and Evaluation of Alternatives to Animal Experiments (ZEBET), Federal Institute for Risk Assessment (BfR), Berlin, Germany
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491
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Rallo R, France B, Liu R, Nair S, George S, Damoiseaux R, Giralt F, Nel A, Bradley K, Cohen Y. Self-organizing map analysis of toxicity-related cell signaling pathways for metal and metal oxide nanoparticles. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2011; 45:1695-702. [PMID: 21250674 PMCID: PMC4418424 DOI: 10.1021/es103606x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The response of a murine macrophage cell line exposed to a library of seven metal and metal oxide nanoparticles was evaluated via High Throughput Screening (HTS) assay employing luciferase-reporters for ten independent toxicity-related signaling pathways. Similarities of toxicity response among the nanoparticles were identified via Self-Organizing Map (SOM) analysis. This analysis, applied to the HTS data, quantified the significance of the signaling pathway responses (SPRs) of the cell population exposed to nanomaterials relative to a population of untreated cells, using the Strictly Standardized Mean Difference (SSMD). Given the high dimensionality of the data and relatively small data set, the validity of the SOM clusters was established via a consensus clustering technique. Analysis of the SPR signatures revealed two cluster groups corresponding to (i) sublethal pro-inflammatory responses to Al2O3, Au, Ag, SiO2 nanoparticles possibly related to ROS generation, and (ii) lethal genotoxic responses due to exposure to ZnO and Pt nanoparticles at a concentration range of 25-100 μg/mL at 12 h exposure. In addition to identifying and visualizing clusters and quantifying similarity measures, the SOM approach can aid in developing predictive quantitative-structure relations; however, this would require significantly larger data sets generated from combinatorial libraries of engineered nanoparticles.
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Affiliation(s)
- Robert Rallo
- Center for the Environmental Implications of Nanotechnology. California Nanosystems Institute, University of California, Los Angeles, CA 90095
- Departament d' Enginyeria Informatica i Matematiques, Universitat Rovira i Virgili, Av. Paisos Catalans 26, 43007 Tarragona, Catalunya, Spain
| | - Bryan France
- Center for the Environmental Implications of Nanotechnology. California Nanosystems Institute, University of California, Los Angeles, CA 90095
| | - Rong Liu
- Center for the Environmental Implications of Nanotechnology. California Nanosystems Institute, University of California, Los Angeles, CA 90095
| | - Sumitra Nair
- Center for the Environmental Implications of Nanotechnology. California Nanosystems Institute, University of California, Los Angeles, CA 90095
| | - Saji George
- Center for the Environmental Implications of Nanotechnology. California Nanosystems Institute, University of California, Los Angeles, CA 90095
- Department of Medicine - Div. of NanoMedicine, University of California, Los Angeles, CA 90095
| | - Robert Damoiseaux
- Departament d' Enginyeria Informatica i Matematiques, Universitat Rovira i Virgili, Av. Paisos Catalans 26, 43007 Tarragona, Catalunya, Spain
| | - Francesc Giralt
- Departament d' Enginyeria Informatica i Matematiques, Universitat Rovira i Virgili, Av. Paisos Catalans 26, 43007 Tarragona, Catalunya, Spain
- Departament d' Enginyeria Quimica, Universitat Rovira i Virgili, Av. Paisos Catalans 26, 43007 Tarragona, Catalunya, Spain
| | - Andre Nel
- Center for the Environmental Implications of Nanotechnology. California Nanosystems Institute, University of California, Los Angeles, CA 90095
- Department of Medicine - Div. of NanoMedicine, University of California, Los Angeles, CA 90095
| | - Kenneth Bradley
- Center for the Environmental Implications of Nanotechnology. California Nanosystems Institute, University of California, Los Angeles, CA 90095
| | - Yoram Cohen
- Center for the Environmental Implications of Nanotechnology. California Nanosystems Institute, University of California, Los Angeles, CA 90095
- Chemical and Biomolecular Engineering Department. University of California, Los Angeles, Los Angeles, CA 90095
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492
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Integrating mechanistic and polymorphism data to characterize human genetic susceptibility for environmental chemical risk assessment in the 21st century. Toxicol Appl Pharmacol 2011; 271:395-404. [PMID: 21291902 DOI: 10.1016/j.taap.2011.01.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Revised: 12/28/2010] [Accepted: 01/24/2011] [Indexed: 12/27/2022]
Abstract
Response to environmental chemicals can vary widely among individuals and between population groups. In human health risk assessment, data on susceptibility can be utilized by deriving risk levels based on a study of a susceptible population and/or an uncertainty factor may be applied to account for the lack of information about susceptibility. Defining genetic susceptibility in response to environmental chemicals across human populations is an area of interest in the NAS' new paradigm of toxicity pathway-based risk assessment. Data from high-throughput/high content (HT/HC), including -omics (e.g., genomics, transcriptomics, proteomics, metabolomics) technologies, have been integral to the identification and characterization of drug target and disease loci, and have been successfully utilized to inform the mechanism of action for numerous environmental chemicals. Large-scale population genotyping studies may help to characterize levels of variability across human populations at identified target loci implicated in response to environmental chemicals. By combining mechanistic data for a given environmental chemical with next generation sequencing data that provides human population variation information, one can begin to characterize differential susceptibility due to genetic variability to environmental chemicals within and across genetically heterogeneous human populations. The integration of such data sources will be informative to human health risk assessment.
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493
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Guo L, Qian JY, Abrams R, Tang HM, Weiser T, Sanders MJ, Kolaja KL. The Electrophysiological Effects of Cardiac Glycosides in Human iPSC-derived Cardiomyocytes and in Guinea Pig Isolated Hearts. Cell Physiol Biochem 2011; 27:453-62. [DOI: 10.1159/000329966] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/12/2011] [Indexed: 01/15/2023] Open
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494
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Mossman BT, Lippmann M, Hesterberg TW, Kelsey KT, Barchowsky A, Bonner JC. Pulmonary endpoints (lung carcinomas and asbestosis) following inhalation exposure to asbestos. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2011; 14:76-121. [PMID: 21534086 PMCID: PMC3118517 DOI: 10.1080/10937404.2011.556047] [Citation(s) in RCA: 135] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Lung carcinomas and pulmonary fibrosis (asbestosis) occur in asbestos workers. Understanding the pathogenesis of these diseases is complicated because of potential confounding factors, such as smoking, which is not a risk factor in mesothelioma. The modes of action (MOA) of various types of asbestos in the development of lung cancers, asbestosis, and mesotheliomas appear to be different. Moreover, asbestos fibers may act differentially at various stages of these diseases, and have different potencies as compared to other naturally occurring and synthetic fibers. This literature review describes patterns of deposition and retention of various types of asbestos and other fibers after inhalation, methods of translocation within the lung, and dissolution of various fiber types in lung compartments and cells in vitro. Comprehensive dose-response studies at fiber concentrations inhaled by humans as well as bivariate size distributions (lengths and widths), types, and sources of fibers are rarely defined in published studies and are needed. Species-specific responses may occur. Mechanistic studies have some of these limitations, but have suggested that changes in gene expression (either fiber-catalyzed directly or by cell elaboration of oxidants), epigenetic changes, and receptor-mediated or other intracellular signaling cascades may play roles in various stages of the development of lung cancers or asbestosis.
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Affiliation(s)
- Brooke T Mossman
- Department of Pathology, University of Vermont College of Medicine, Burlington, Vermont 05405, USA.
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495
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Aust AE, Cook PM, Dodson RF. Morphological and chemical mechanisms of elongated mineral particle toxicities. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2011; 14:40-75. [PMID: 21534085 PMCID: PMC3118489 DOI: 10.1080/10937404.2011.556046] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Much of our understanding regarding the mechanisms for induction of disease following inhalation of respirable elongated mineral particles (REMP) is based on studies involving the biological effects of asbestos fibers. The factors governing the disease potential of an exposure include duration and frequency of exposures; tissue-specific dose over time; impacts on dose persistence from in vivo REMP dissolution, comminution, and clearance; individual susceptibility; and the mineral type and surface characteristics. The mechanisms associated with asbestos particle toxicity involve two facets for each particle's contribution: (1) the physical features of the inhaled REMP, which include width, length, aspect ratio, and effective surface area available for cell contact; and (2) the surface chemical composition and reactivity of the individual fiber/elongated particle. Studies in cell-free systems and with cultured cells suggest an important way in which REMP from asbestos damage cellular molecules or influence cellular processes. This may involve an unfortunate combination of the ability of REMP to chemically generate potentially damaging reactive oxygen species, through surface iron, and the interaction of the unique surfaces with cell membranes to trigger membrane receptor activation. Together these events appear to lead to a cascade of cellular events, including the production of damaging reactive nitrogen species, which may contribute to the disease process. Thus, there is a need to be more cognizant of the potential impact that the total surface area of REMP contributes to the generation of events resulting in pathological changes in biological systems. The information presented has applicability to inhaled dusts, in general, and specifically to respirable elongated mineral particles.
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Affiliation(s)
- Ann E. Aust
- Chemistry and Biochemistry Department (Emeritus), Utah State University, Huachuca City, Arizona
| | - Philip M. Cook
- U.S. EPA NHEERL Mid-Continent Ecology Division, Duluth, Minnesota
| | - Ronald F. Dodson
- Dodson Environmental Consulting, Inc., and ERI Environmental Consulting, Inc., Tyler, Texas, USA
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496
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Andersen ME, Clewell HJ, Bermudez E, Dodd DE, Willson GA, Campbell JL, Thomas RS. Formaldehyde: Integrating Dosimetry, Cytotoxicity, and Genomics to Understand Dose-Dependent Transitions for an Endogenous Compound. Toxicol Sci 2010; 118:716-31. [DOI: 10.1093/toxsci/kfq303] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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497
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Andersen ME, Al-Zoughool M, Croteau M, Westphal M, Krewski D. The future of toxicity testing. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2010; 13:163-196. [PMID: 20574896 DOI: 10.1080/10937404.2010.483933] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
In 2007, the U.S. National Research Council (NRC) released a report, "Toxicity Testing in the 21st Century: A Vision and a Strategy," that proposes a paradigm shift for toxicity testing of environmental agents. The vision is based on the notion that exposure to environmental agents leads to adverse health outcomes through the perturbation of toxicity pathways that are operative in humans. Implementation of the NRC vision will involve a fundamental change in the assessment of toxicity of environmental agents, moving away from adverse health outcomes observed in experimental animals to the identification of critical perturbations of toxicity pathways. Pathway perturbations will be identified using in vitro assays and quantified for dose response using methods in computational toxicology and other recent scientific advances in basic biology. Implementation of the NRC vision will require a major research effort, not unlike that required to successfully map the human genome, extending over 10 to 20 years, involving the broad scientific community to map important toxicity pathways operative in humans. This article provides an overview of the scientific tools and technologies that will form the core of the NRC vision for toxicity testing. Of particular importance will be the development of rapidly performed in vitro screening assays using human cells and cell lines or human tissue surrogates to efficiently identify environmental agents producing critical pathway perturbations. In addition to the overview of the NRC vision, this study documents the reaction by a number of stakeholder groups since 2007, including the scientific, risk assessment, regulatory, and animal welfare communities.
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Affiliation(s)
- Melvin E Andersen
- Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina, USA
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498
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Judson R, Elloumi F, Setzer RW, Li Z, Shah I. A comparison of machine learning algorithms for chemical toxicity classification using a simulated multi-scale data model. BMC Bioinformatics 2008; 9:241. [PMID: 18489778 PMCID: PMC2409339 DOI: 10.1186/1471-2105-9-241] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2008] [Accepted: 05/19/2008] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND Bioactivity profiling using high-throughput in vitro assays can reduce the cost and time required for toxicological screening of environmental chemicals and can also reduce the need for animal testing. Several public efforts are aimed at discovering patterns or classifiers in high-dimensional bioactivity space that predict tissue, organ or whole animal toxicological endpoints. Supervised machine learning is a powerful approach to discover combinatorial relationships in complex in vitro/in vivo datasets. We present a novel model to simulate complex chemical-toxicology data sets and use this model to evaluate the relative performance of different machine learning (ML) methods. RESULTS The classification performance of Artificial Neural Networks (ANN), K-Nearest Neighbors (KNN), Linear Discriminant Analysis (LDA), Naïve Bayes (NB), Recursive Partitioning and Regression Trees (RPART), and Support Vector Machines (SVM) in the presence and absence of filter-based feature selection was analyzed using K-way cross-validation testing and independent validation on simulated in vitro assay data sets with varying levels of model complexity, number of irrelevant features and measurement noise. While the prediction accuracy of all ML methods decreased as non-causal (irrelevant) features were added, some ML methods performed better than others. In the limit of using a large number of features, ANN and SVM were always in the top performing set of methods while RPART and KNN (k = 5) were always in the poorest performing set. The addition of measurement noise and irrelevant features decreased the classification accuracy of all ML methods, with LDA suffering the greatest performance degradation. LDA performance is especially sensitive to the use of feature selection. Filter-based feature selection generally improved performance, most strikingly for LDA. CONCLUSION We have developed a novel simulation model to evaluate machine learning methods for the analysis of data sets in which in vitro bioassay data is being used to predict in vivo chemical toxicology. From our analysis, we can recommend that several ML methods, most notably SVM and ANN, are good candidates for use in real world applications in this area.
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Affiliation(s)
- Richard Judson
- National Center for Computational Toxicology, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA.
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