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Sewer A, Talikka M, Calvino-Martin F, Luettich K, Iskandar A. Quantitative modeling of in vitro data using an adverse outcome pathway for the risk assessment of decreased lung function in humans. Toxicol Lett 2024; 393:107-113. [PMID: 38350531 DOI: 10.1016/j.toxlet.2024.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 01/18/2024] [Accepted: 02/07/2024] [Indexed: 02/15/2024]
Abstract
In the absence of epidemiological data, there is a need to develop computational models that convert in vitro findings to human disease risk predictions following toxicant exposure. In such efforts, in vitro data can be evaluated in the context of adverse outcome pathways (AOPs) that organize mechanistic knowledge based on empirical evidence into a sequence of molecular-, cellular-, tissue-, and organ-level key events that precede an adverse outcome (AO). Here we combined data from advanced in vitro organotypic airway models exposed to combustible cigarette (CC) smoke or Tobacco Heating System (THS) aerosol with an AOP for increased oxidative stress leads to decreased lung function. The mathematical modeling predicted reduced risk of decreased ciliary beating frequency (CBF) based on oxidative stress measurements and reduced risk of decreased mucociliary clearance (MCC) based on CBF measurements in THS aerosol- compared with CC smoke-exposed cultures. To extend the predictions to the AO of decreased lung function, we leveraged human MCC data from current smokers, nonsmokers, former smokers, and users of heated tobacco products. This approach provided a plausible prediction of diminished reduction in lung function in response to THS use compared with continued smoking. The current approach may also present a basis for an integrated approach to testing and assessment of tobacco products for future regulatory decision-making.
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Affiliation(s)
- Alain Sewer
- PMI R&D, Philip Morris Products S.A., Neuchâtel, Switzerland.
| | - Marja Talikka
- PMI R&D, Philip Morris Products S.A., Neuchâtel, Switzerland
| | | | - Karsta Luettich
- PMI R&D, Philip Morris Products S.A., Neuchâtel, Switzerland
| | - Anita Iskandar
- PMI R&D, Philip Morris Products S.A., Neuchâtel, Switzerland
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2
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Corvaro M, Henriquez J, Settivari R, Mattson U, Forreryd A, Gradin R, Johansson H, Gehen S. GARD™skin and GARD™potency: A proof-of-concept study investigating applicability domain for agrochemical formulations. Regul Toxicol Pharmacol 2024; 148:105595. [PMID: 38453128 DOI: 10.1016/j.yrtph.2024.105595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 02/19/2024] [Accepted: 02/26/2024] [Indexed: 03/09/2024]
Abstract
Several New Approach Methodologies (NAMs) for hazard assessment of skin sensitisers have been formally validated. However, data regarding their applicability on certain product classes are limited. The purpose of this project was to provide initial evidence on the applicability domain of GARD™skin and GARD™potency for the product class of agrochemical formulations. For this proof of concept, 30 liquid and 12 solid agrochemical formulations were tested in GARDskin for hazard predictions. Formulations predicted as sensitisers were further evaluated in the GARDpotency assay to determine GHS skin sensitisation category. The selected formulations were of product types, efficacy groups and sensitisation hazard classes representative of the industry's products. The performance of GARDskin was estimated by comparing results to existing in vivo animal data. The overall accuracy, sensitivity, and specificity were 76.2% (32/42), 85.0% (17/20), and 68.2% (15/22), respectively, with the predictivity for liquid formulations being slightly higher compared to the solid formulations. GARDpotency correctly subcategorized 14 out of the 17 correctly predicted sensitisers. Lack of concordance was justifiable by compositional or borderline response analysis. In conclusion, GARDskin and GARDpotency showed satisfactory performance in this initial proof-of-concept study, which supports consideration of agrochemical formulations being within the applicability domain of the test methods.
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Affiliation(s)
| | | | | | | | | | | | | | - Sean Gehen
- Corteva™ Agriscience LCC, Indianapolis, IN, USA.
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3
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Zhao H, Chen Z, Kang X, Yang B, Luo P, Li H, He Q. The frontline of alternatives to animal testing: novel in vitro skin model application in drug development and evaluation. Toxicol Sci 2023; 196:152-169. [PMID: 37702017 DOI: 10.1093/toxsci/kfad093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/14/2023] Open
Abstract
The FDA Modernization Act 2.0 has brought nonclinical drug evaluation into a new era. In vitro models are widely used and play an important role in modern drug development and evaluation, including early candidate drug screening and preclinical drug efficacy and toxicity assessment. Driven by regulatory steering and facilitated by well-defined physiology, novel in vitro skin models are emerging rapidly, becoming the most advanced area in alternative testing research. The revolutionary technologies bring us many in vitro skin models, either laboratory-developed or commercially available, which were all built to emulate the structure of the natural skin to recapitulate the skin's physiological function and particular skin pathology. During the model development, how to achieve balance among complexity, accessibility, capability, and cost-effectiveness remains the core challenge for researchers. This review attempts to introduce the existing in vitro skin models, align them on different dimensions, such as structural complexity, functional maturity, and screening throughput, and provide an update on their current application in various scenarios within the scope of chemical testing and drug development, including testing in genotoxicity, phototoxicity, skin sensitization, corrosion/irritation. Overall, the review will summarize a general strategy for in vitro skin model to enhance future model invention, application, and translation in drug development and evaluation.
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Affiliation(s)
- He Zhao
- Center for Drug Safety Evaluation and Research of Zhejiang University, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Zhaozeng Chen
- Innovation Institute for Artificial Intelligence in Medicine of Zhejiang University, Hangzhou 310018, China
| | - Xingchen Kang
- Center for Drug Safety Evaluation and Research of Zhejiang University, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Bo Yang
- Institute of Pharmacology & Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Peihua Luo
- Center for Drug Safety Evaluation and Research of Zhejiang University, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
- Innovation Institute for Artificial Intelligence in Medicine of Zhejiang University, Hangzhou 310018, China
| | - Hui Li
- Center for Drug Safety Evaluation and Research of Zhejiang University, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
- Innovation Institute for Artificial Intelligence in Medicine of Zhejiang University, Hangzhou 310018, China
| | - Qiaojun He
- Center for Drug Safety Evaluation and Research of Zhejiang University, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
- Innovation Institute for Artificial Intelligence in Medicine of Zhejiang University, Hangzhou 310018, China
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Evans MV, Moxon TE, Lian G, Deacon BN, Chen T, Adams LD, Meade A, Wambaugh JF. A regression analysis using simple descriptors for multiple dermal datasets: Going from individual membranes to the full skin. J Appl Toxicol 2023; 43:940-950. [PMID: 36609694 PMCID: PMC10367137 DOI: 10.1002/jat.4435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 01/04/2023] [Accepted: 01/05/2023] [Indexed: 01/09/2023]
Abstract
In silico methods to estimate and/or quantify skin absorption of chemicals as a function of chemistry are needed to realistically predict pharmacological, occupational, and environmental exposures. The Potts-Guy equation is a well-established approach, using multi-linear regression analysis describing skin permeability (Kp) in terms of the octanol/water partition coefficient (logP) and molecular weight (MW). In this work, we obtained regression equations for different human datasets relevant to environmental and cosmetic chemicals. Since the Potts-Guy equation was published in 1992, we explored recent datasets that include different skin layers, such as dermatomed (including dermis to a defined thickness) and full skin. Our work was consistent with others who have observed that fits to the Potts-Guy equation are stronger for experiments focused on the epidermis. Permeability estimates for dermatomed skin and full skin resulted in low regression coefficients when compared to epidermis datasets. An updated regression equation uses a combination of fitted permeability values obtained with a published 2D compartmental model previously evaluated. The resulting regression equation was: logKp = -2.55 + 0.65logP - 0.0085MW, R2 = 0.91 (applicability domain for all datasets: MW ranges from 18 to >584 g/mol and -4 to >5 for logP). This approach demonstrates the advantage of combining mechanistic with structural activity relationships in a single modeling approach. This combination approach results in an improved regression fit when compared to permeability estimates obtained using the Potts-Guy approach alone. The analysis presented in this work assumes a one-compartment skin absorption route; future modeling work will consider adding multiple compartments.
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Affiliation(s)
- Marina V Evans
- Center for Computational Toxicology and Exposure, ORD, RTP, US EPA, Durham, North Carolina, USA
| | - Thomas E Moxon
- Unilever Safety and Environmental Assurance Centre, Bedfordshire, UK
| | | | - Benjamin N Deacon
- Department of Chemical and Processing Engineering, UK University of Surrey, Guildford, UK
| | - Tao Chen
- Department of Chemical and Processing Engineering, UK University of Surrey, Guildford, UK
| | - Linda D Adams
- Center for Computational Toxicology and Exposure, ORD, RTP, US EPA, Durham, North Carolina, USA
| | | | - John F Wambaugh
- Center for Computational Toxicology and Exposure, ORD, RTP, US EPA, Durham, North Carolina, USA
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Seo JA, Cho SA, Park CE, Seo DH, Choi M, An S, Kim BH. Pre-validation study of spectrophotometric direct peptide reactivity assay (Spectro-DPRA) as a modified in chemico skin sensitization test method. Toxicol Res 2022; 38:531-544. [PMID: 36277359 PMCID: PMC9532475 DOI: 10.1007/s43188-022-00130-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 02/24/2022] [Accepted: 03/14/2022] [Indexed: 10/18/2022] Open
Abstract
Skin sensitization is induced when certain chemicals bind to skin proteins. Direct peptide reactivity assay (DPRA) has been adopted by the OECD as an alternative method to evaluate skin sensitization by assessing a substance's reaction to two model peptides. A modified spectrophotometric method, Spectro-DPRA, can evaluate skin sensitization, in a high throughput fashion, to obviate some limitations of DPRA. Pre-validation studies for Spectro-DPRA were conducted to determine transferability and proficiency, within- and between-laboratory reproducibility, and predictive ability based on GLP principles at three laboratories (AP, KTR, and KCL). All laboratories confirmed high (> 90%) concordance for evaluating the sensitivity induced by ten chemical substances. The concordance among the three tests performed by each laboratory was 90% for AP, 100% for KTR, and 100% for KCL. The mean accuracy of the laboratories was 93.3% [compared to the standard operating procedure (SOP)]. The reproducibility among the three laboratories was as high as 86.7%; the accuracy was 86.7% for AP, 100% for KTR, and 86.7% for KCL (compared to the SOP). An additional 54 substances were assessed in 3 separate labs to verify the prediction rate. Based on the result, 29 out of 33 substances were classified as sensitizers, and 19 out of 21 identified as non-sensitizers; the corresponding sensitivity, specificity, and accuracy values were 87.9%, 90.5%, and 88.9%, respectively. These findings indicate that the Spectro-DPRA can address the molecular initiating event with improved predictability and reproducibility, while saving time and cost compared to DPRA or ADRA.
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Affiliation(s)
- Jung-Ah Seo
- Department of Public Health, Keimyung University, 1095 Dalgubeol-daero, Dalseo-gu, Daegu, 42601 Republic of Korea
| | - Sun-A Cho
- Safety and Microbiology Lab, Amorepacific Corporation R&D Center, Yongin-si, Republic of Korea
| | - Chang Eon Park
- Korea Testing and Research Institute, Hwasun, Republic of Korea
| | - Dong Hyuk Seo
- Korea Conformity Laboratories, Incheon, Republic of Korea
| | - Myungsuk Choi
- Department of Public Health Science, Korea University, Seoul, Republic of Korea
| | - Susun An
- Safety and Microbiology Lab, Amorepacific Corporation R&D Center, Yongin-si, Republic of Korea
| | - Bae-Hwan Kim
- Department of Public Health, Keimyung University, 1095 Dalgubeol-daero, Dalseo-gu, Daegu, 42601 Republic of Korea
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6
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Edwards SW, Nelms M, Hench VK, Ponder J, Sullivan K. Mapping Mechanistic Pathways of Acute Oral Systemic Toxicity Using Chemical Structure and Bioactivity Measurements. Front Toxicol 2022; 4:824094. [PMID: 35295211 PMCID: PMC8915918 DOI: 10.3389/ftox.2022.824094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 01/31/2022] [Indexed: 12/16/2022] Open
Abstract
Regulatory agencies around the world have committed to reducing or eliminating animal testing for establishing chemical safety. Adverse outcome pathways can facilitate replacement by providing a mechanistic framework for identifying the appropriate non-animal methods and connecting them to apical adverse outcomes. This study separated 11,992 chemicals with curated rat oral acute toxicity information into clusters of structurally similar compounds. Each cluster was then assigned one or more ToxCast/Tox21 assays by looking for the minimum number of assays required to record at least one positive hit call below cytotoxicity for all acutely toxic chemicals in the cluster. When structural information is used to select assays for testing, none of the chemicals required more than four assays and 98% required two assays or less. Both the structure-based clusters and activity from the associated assays were significantly associated with the GHS toxicity classification of the chemicals, which suggests that a combination of bioactivity and structural information could be as reproducible as traditional in vivo studies. Predictivity is improved when the in vitro assay directly corresponds to the mechanism of toxicity, but many indirect assays showed promise as well. Given the lower cost of in vitro testing, a small assay battery including both general cytotoxicity assays and two or more orthogonal assays targeting the toxicological mechanism could be used to improve performance further. This approach illustrates the promise of combining existing in silico approaches, such as the Collaborative Acute Toxicity Modeling Suite (CATMoS), with structure-based bioactivity information as part of an efficient tiered testing strategy that can reduce or eliminate animal testing for acute oral toxicity.
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Affiliation(s)
- Stephen W. Edwards
- GenOmics, Bioinformatics, and Translational Research Center, RTI International, Research Triangle Park, Durham, NC, United States
- *Correspondence: Stephen W. Edwards, ; Kristie Sullivan,
| | - Mark Nelms
- GenOmics, Bioinformatics, and Translational Research Center, RTI International, Research Triangle Park, Durham, NC, United States
| | - Virginia K. Hench
- GenOmics, Bioinformatics, and Translational Research Center, RTI International, Research Triangle Park, Durham, NC, United States
| | - Jessica Ponder
- Physicians Committee for Responsible Medicine, Washington, DC, United States
| | - Kristie Sullivan
- Physicians Committee for Responsible Medicine, Washington, DC, United States
- *Correspondence: Stephen W. Edwards, ; Kristie Sullivan,
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7
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Romeo D, Salieri B, Hischier R, Nowack B, Wick P. An integrated pathway based on in vitro data for the human hazard assessment of nanomaterials. Environ Int 2020; 137:105505. [PMID: 32014789 DOI: 10.1016/j.envint.2020.105505] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 12/13/2019] [Accepted: 01/17/2020] [Indexed: 05/23/2023]
Abstract
In line with the 3R concept, nanotoxicology is shifting from a phenomenological to a mechanistic approach based on in vitro and in silico methods, with a consequent reduction in animal testing. Risk Assessment (RA) and Life Cycle Assessment (LCA) methodologies, which traditionally rely on in vivo toxicity studies, will not be able to keep up with the pace of development of new nanomaterials unless they adapt to use this new type of data. While tools and models are already available and show a great potential for future use in RA and LCA, currently none is able alone to quantitatively assess human hazards (i.e. calculate chronic NOAEL or ED50 values). By highlighting which models and approaches can be used in a quantitative way with the available knowledge and data, we propose an integrated pathway for the use of in vitro data in RA and LCA. Starting with the characterization of nanoparticles' properties, the pathway then investigates how to select relevant in vitro human data, and how to bridge in vitro dose-response relationships to in vivo effects. If verified, this approach would allow RA and LCA to stir up the development of nanotoxicology by giving indications about the data and quality requirements needed in risk methodologies.
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Affiliation(s)
- Daina Romeo
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Particles-Biology Interactions Laboratory, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland.
| | - Beatrice Salieri
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Technology and Society Laboratory, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland.
| | - Roland Hischier
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Technology and Society Laboratory, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland.
| | - Bernd Nowack
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Technology and Society Laboratory, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland.
| | - Peter Wick
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Particles-Biology Interactions Laboratory, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland.
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8
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Parkinson E, Aleksic M, Arthur R, Regufe Da Mota S, Cubberley R, Skipp PJ. Proteomic analysis of haptenation by skin sensitisers: Diphencyprone and ethyl acrylate. Toxicol In Vitro 2020; 62:104697. [DOI: 10.1016/j.tiv.2019.104697] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 10/16/2019] [Accepted: 10/21/2019] [Indexed: 02/06/2023]
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Allen TEH, Goodman JM, Gutsell S, Russell PJ. Using 2D Structural Alerts to Define Chemical Categories for Molecular Initiating Events. Toxicol Sci 2019; 165:213-223. [PMID: 30020496 DOI: 10.1093/toxsci/kfy144] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Molecular initiating events (MIEs) are important concepts for in silico predictions. They can be used to link chemical characteristics to biological activity through an adverse outcome pathway (AOP). In this work, we capture chemical characteristics in 2D structural alerts, which are then used as models to predict MIEs. An automated procedure has been used to identify these alerts, and the chemical categories they define have been used to provide quantitative predictions for the activity of molecules that contain them. This has been done across a diverse group of 39 important pharmacological human targets using open source data. The alerts for each target combine into a model for that target, and these models are joined into a tool for MIE prediction with high average model performance (sensitivity = 82%, specificity = 93%, overall quality = 93%, Matthews correlation coefficient = 0.57). The result is substantially improved from our previous study (Allen, T. E. H., Goodman, J. M., Gutsell, S., and Russell, P. J. 2016. A history of the molecular initiating event. Chem. Res. Toxicol. 29, 2060-2070) for which the mean sensitivity for each target was only 58%. This tool provides the first step in an AOP-based risk assessment, linking chemical structure to toxicity endpoint.
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Affiliation(s)
- Timothy E H Allen
- Centre for Molecular Informatics, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Jonathan M Goodman
- Centre for Molecular Informatics, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Steve Gutsell
- Unilever Safety and Environmental Assurance Centre, Colworth Science Park, Sharnbrook, Bedfordshire MK44 1LQ, United Kingdom
| | - Paul J Russell
- Unilever Safety and Environmental Assurance Centre, Colworth Science Park, Sharnbrook, Bedfordshire MK44 1LQ, United Kingdom
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11
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Ward JP, Franks SJ, Tindall MJ, King JR, Curtis A, Evans GS. Mathematical modelling of contact dermatitis from nickel and chromium. J Math Biol 2019; 79:595-630. [PMID: 31197444 PMCID: PMC6647287 DOI: 10.1007/s00285-019-01371-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 04/08/2019] [Indexed: 01/21/2023]
Abstract
Dermal exposure to metal allergens can lead to irritant and allergic contact dermatitis (ACD). In this paper we present a mathematical model of the absorption of metal ions, hexavalent chromium and nickel, into the viable epidermis and compare the localised irritant and T-lymphocyte (T-cell) mediated immune responses. The model accounts for the spatial-temporal variation of skin health, extra and intracellular allergen concentrations, innate immune cells, T-cells, cytokine signalling and lymph node activity up to about 6 days after contact with these metals; repair processes associated with withdrawal of exposure to both metals is not considered in the current model, being assumed secondary during the initial phases of exposure. Simulations of the resulting system of PDEs are studied in one-dimension, i.e. across skin depth, and three-dimensional scenarios with the aim of comparing the responses to the two ions in the cases of first contact (no T-cells initially present) and second contact (T-cells initially present). The results show that on continuous contact, chromium ions elicit stronger skin inflammation, but for nickel, subsequent re-exposure stimulates stronger responses due to an accumulation of cytotoxic T-cell mediated responses which characterise ACD. Furthermore, the surface area of contact to these metals has little effect on the speed of response, whilst sensitivity is predicted to increase with the thickness of skin. The modelling approach is generic and should be applicable to describe contact dermatitis from a wide range of allergens.
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Affiliation(s)
- J P Ward
- Department of Mathematical Sciences, Loughborough University, Loughborough, LE11 3TU, UK.
| | - S J Franks
- School of Mathematical Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | - M J Tindall
- Department of Mathematics and Statistics, University of Reading, Reading, Berkshire, RG6 6AX, UK
- Institute for Cardiovascular and Metabolic Research, University of Reading, Reading, RG6 6AA, UK
| | - J R King
- School of Mathematical Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | - A Curtis
- Health and Safety Laboratory, Harpur Hill, Buxton, Derbyshire, SK17 9JN, UK
| | - G S Evans
- Health and Safety Laboratory, Harpur Hill, Buxton, Derbyshire, SK17 9JN, UK
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Mieremet A, Vázquez García A, Boiten W, van Dijk R, Gooris G, Bouwstra JA, El Ghalbzouri A. Human skin equivalents cultured under hypoxia display enhanced epidermal morphogenesis and lipid barrier formation. Sci Rep 2019; 9:7811. [PMID: 31127151 DOI: 10.1038/s41598-019-44204-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 05/02/2019] [Indexed: 12/17/2022] Open
Abstract
Human skin equivalents (HSEs) are three-dimensional cell models mimicking characteristics of native human skin (NHS) in many aspects. However, a limitation of HSEs is the altered in vitro morphogenesis and barrier formation. Differences between in vitro and in vivo skin could have been induced by suboptimal cell culture conditions, of which the level of oxygen in vitro (20%) is much higher than in vivo (0.5-8%). Our aim is to study how external oxygen levels affect epidermal morphogenesis and barrier formation in HSEs. In the present study, fibroblast and keratinocyte monocultures, and HSEs were generated under 20% (normoxia) and 3% (hypoxia) oxygen level. In all cultures under hypoxia, expression of hypoxia-inducible factor target genes was increased. Characterization of HSEs generated under hypoxia using immunohistochemical analyses of morphogenesis biomarkers revealed a reduction in epidermal thickness, reduced proliferation, similar early differentiation, and an attenuated terminal differentiation program compared to normoxia, better mimicking NHS. The stratum corneum ceramide composition was studied with liquid chromatography coupled to mass spectrometry. Under hypoxia, HSEs exhibited a ceramide composition that more closely resembles that of NHS. Consequently, the lipid organization was improved. In conclusion, epidermal morphogenesis and barrier formation in HSEs reconstructed under hypoxia better mimics that of NHS.
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Ciallella HL, Zhu H. Advancing Computational Toxicology in the Big Data Era by Artificial Intelligence: Data-Driven and Mechanism-Driven Modeling for Chemical Toxicity. Chem Res Toxicol 2019; 32:536-547. [PMID: 30907586 DOI: 10.1021/acs.chemrestox.8b00393] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In 2016, the Frank R. Lautenberg Chemical Safety for the 21st Century Act became the first US legislation to advance chemical safety evaluations by utilizing novel testing approaches that reduce the testing of vertebrate animals. Central to this mission is the advancement of computational toxicology and artificial intelligence approaches to implementing innovative testing methods. In the current big data era, the terms volume (amount of data), velocity (growth of data), and variety (the diversity of sources) have been used to characterize the currently available chemical, in vitro, and in vivo data for toxicity modeling purposes. Furthermore, as suggested by various scientists, the variability (internal consistency or lack thereof) of publicly available data pools, such as PubChem, also presents significant computational challenges. The development of novel artificial intelligence approaches based on public massive toxicity data is urgently needed to generate new predictive models for chemical toxicity evaluations and make the developed models applicable as alternatives for evaluating untested compounds. In this procedure, traditional approaches (e.g., QSAR) purely based on chemical structures have been replaced by newly designed data-driven and mechanism-driven modeling. The resulting models realize the concept of adverse outcome pathway (AOP), which can not only directly evaluate toxicity potentials of new compounds, but also illustrate relevant toxicity mechanisms. The recent advancement of computational toxicology in the big data era has paved the road to future toxicity testing, which will significantly impact on the public health.
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Abstract
The field of experimental toxicology is rapidly advancing by incorporating novel techniques and methods that provide a much more granular view into the mechanisms of potential adverse effects of chemical exposures on human health. The data from various in vitro assays and computational models are useful not only for increasing confidence in hazard and risk decisions, but also are enabling better, faster and cheaper assessment of a greater number of compounds, mixtures, and complex products. This is of special value to the field of green chemistry where design of new materials or alternative uses of existing ones is driven, at least in part, by considerations of safety. This article reviews the state of the science and decision-making in scenarios when little to no data may be available to draw conclusions about which choice in green chemistry is "safer." It is clear that there is no "one size fits all" solution and multiple data streams need to be weighed in making a decision. Moreover, the overall level of familiarity of the decision-makers and scientists alike with new assessment methodologies, their validity, value and limitations is evolving. Thus, while the "impact" of the new developments in toxicology on the field of green chemistry is great already, it is premature to conclude that the data from new assessment methodologies have been widely accepted yet.
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Affiliation(s)
- Ivan Rusyn
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas 77843
| | - Nigel Greene
- Predictive Compound Safety and ADME, AstraZeneca Pharmaceuticals LP, Waltham, Massachusetts 02451
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Kimber I, Poole A, Basketter DA. Skin and respiratory chemical allergy: confluence and divergence in a hybrid adverse outcome pathway. Toxicol Res (Camb) 2018; 7:586-605. [PMID: 30090609 PMCID: PMC6060610 DOI: 10.1039/c7tx00272f] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 01/18/2018] [Indexed: 12/14/2022] Open
Abstract
Sensitisation of the respiratory tract to chemicals resulting in respiratory allergy and allergic asthma is an important occupational health problem, and presents toxicologists with no shortage of challenges. A major issue is that there are no validated or, even widely recognised, methods available for the identification and characterisation of chemical respiratory allergens, or for distinguishing respiratory allergens from contact allergens. The first objective here has been review what is known (and what is not known) of the mechanisms through which chemicals induce sensitisation of the respiratory tract, and to use this information to construct a hybrid Adverse Outcome Pathway (AOP) that combines consideration of both skin and respiratory sensitisation. The intention then has been to use the construction of this hybrid AOP to identify areas of commonality/confluence, and areas of departure/divergence, between skin sensitisation and sensitisation of the respiratory tract. The hybrid AOP not only provides a mechanistic understanding of how the processes of skin and respiratory sensitisation differ, buy also a means of identifying areas of uncertainty about chemical respiratory allergy that benefit from a further investment in research.
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Affiliation(s)
- Ian Kimber
- Faculty of Biology , Medicine and Health , University of Manchester , Oxford Road , Manchester M13 9PT , UK . ; Tel: +44 (0) 161 275 1587
| | - Alan Poole
- European Centre for Ecotoxicology and Toxicology of Chemicals (ECETOC) , 2 Av E Van Nieuwenhuyse , 1160 Brussels , Belgium
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Carusi A, Davies MR, De Grandis G, Escher BI, Hodges G, Leung KMY, Whelan M, Willett C, Ankley GT. Harvesting the promise of AOPs: An assessment and recommendations. Sci Total Environ 2018; 628-629:1542-1556. [PMID: 30045572 PMCID: PMC5888775 DOI: 10.1016/j.scitotenv.2018.02.015] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 02/02/2018] [Accepted: 02/02/2018] [Indexed: 05/22/2023]
Abstract
The Adverse Outcome Pathway (AOP) concept is a knowledge assembly and communication tool to facilitate the transparent translation of mechanistic information into outcomes meaningful to the regulatory assessment of chemicals. The AOP framework and associated knowledgebases (KBs) have received significant attention and use in the regulatory toxicology community. However, it is increasingly apparent that the potential stakeholder community for the AOP concept and AOP KBs is broader than scientists and regulators directly involved in chemical safety assessment. In this paper we identify and describe those stakeholders who currently-or in the future-could benefit from the application of the AOP framework and knowledge to specific problems. We also summarize the challenges faced in implementing pathway-based approaches such as the AOP framework in biological sciences, and provide a series of recommendations to meet critical needs to ensure further progression of the framework as a useful, sustainable and dependable tool supporting assessments of both human health and the environment. Although the AOP concept has the potential to significantly impact the organization and interpretation of biological information in a variety of disciplines/applications, this promise can only be fully realized through the active engagement of, and input from multiple stakeholders, requiring multi-pronged substantive long-term planning and strategies.
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Affiliation(s)
- Annamaria Carusi
- Medical Humanities Sheffield, University of Sheffield, Medical School, Beech Hill Road, Sheffield S10 2RX, UK.
| | | | - Giovanni De Grandis
- Science, Technology, Engineering and Public Policy (STEaPP), Boston House, 36-37 Fitzroy Square, London W1T 6EY, UK.
| | - Beate I Escher
- UFZ - Helmholtz Centre for Environmental Research, 04318 Leipzig, Germany; Eberhard Karls University Tübingen, Environmental Toxicology, Centre for Applied Geosciences, 72074 Tübingen, Germany.
| | - Geoff Hodges
- Safety and Environmental Assurance Centre, Unilever, Colworth Science Park, Sharnbrook, Bedfordshire MK44 1LQ, UK.
| | - Kenneth M Y Leung
- The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China.
| | - Maurice Whelan
- European Commission, Joint Research Centre (JRC), Ispra, Italy.
| | - Catherine Willett
- The Humane Society of the United States, 700 Professional Drive, Gaithersburg, MD, 20879, USA.
| | - Gerald T Ankley
- US Environmental Protection Agency, 6201 Congdon Blvd, Duluth, MN 55804, USA.
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Allen TEH, Grayson MN, Goodman JM, Gutsell S, Russell PJ. Using Transition State Modeling To Predict Mutagenicity for Michael Acceptors. J Chem Inf Model 2018; 58:1266-1271. [PMID: 29847119 DOI: 10.1021/acs.jcim.8b00130] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The Ames mutagenicity assay is a long established in vitro test to measure the mutagenicity potential of a new chemical used in regulatory testing globally. One of the key computational approaches to modeling of the Ames assay relies on the formation of chemical categories based on the different electrophilic compounds that are able to react directly with DNA and form a covalent bond. Such approaches sometimes predict false positives, as not all Michael acceptors are found to be Ames-positive. The formation of such covalent bonds can be explored computationally using density functional theory transition state modeling. We have applied this approach to mutagenicity, allowing us to calculate the activation energy required for α,β-unsaturated carbonyls to react with a model system for the guanine nucleobase of DNA. These calculations have allowed us to identify that chemical compounds with activation energies greater than or equal to 25.7 kcal/mol are not able to bind directly to DNA. This allows us to reduce the false positive rate for computationally predicted mutagenicity assays. This methodology can be used to investigate other covalent-bond-forming reactions that can lead to toxicological outcomes and learn more about experimental results.
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Affiliation(s)
- Timothy E H Allen
- Centre for Molecular Informatics, Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge CB2 1EW , United Kingdom
| | - Matthew N Grayson
- Centre for Molecular Informatics, Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge CB2 1EW , United Kingdom
| | - Jonathan M Goodman
- Centre for Molecular Informatics, Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge CB2 1EW , United Kingdom
| | - Steve Gutsell
- Unilever Safety and Environmental Assurance Centre , Colworth Science Park , Sharnbrook , Bedfordshire MK44 1LQ , United Kingdom
| | - Paul J Russell
- Unilever Safety and Environmental Assurance Centre , Colworth Science Park , Sharnbrook , Bedfordshire MK44 1LQ , United Kingdom
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Abstract
The adverse outcome pathway (AOP) framework serves as a knowledge assembly, interpretation, and communication tool designed to support the translation of pathway-specific mechanistic data into responses relevant to assessing and managing risks of chemicals to human health and the environment. As such, AOPs facilitate the use of data streams often not employed by risk assessors, including information from in silico models, in vitro assays and short-term in vivo tests with molecular/biochemical endpoints. This translational capability can increase the capacity and efficiency of safety assessments both for single chemicals and chemical mixtures. Our mini-review describes the conceptual basis of the AOP framework and aspects of its current status relative to use by toxicologists and risk assessors, including four illustrative applications of the framework to diverse assessment scenarios.
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Affiliation(s)
- Gerald T Ankley
- US Environmental Protection Agency, Office of Research and Development, Mid-Continent Ecology Division, Duluth, MN, USA
| | - Stephen W Edwards
- US Environmental Protection Agency, Office of Research and Development, Integrated Systems Toxicology Division, RTP, NC, USA
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Kleinstreuer NC, Hoffmann S, Alépée N, Allen D, Ashikaga T, Casey W, Clouet E, Cluzel M, Desprez B, Gellatly N, Göbel C, Kern PS, Klaric M, Kühnl J, Martinozzi-Teissier S, Mewes K, Miyazawa M, Strickland J, van Vliet E, Zang Q, Petersohn D. Non-animal methods to predict skin sensitization (II): an assessment of defined approaches *. Crit Rev Toxicol 2018; 48:359-374. [PMID: 29474122 PMCID: PMC7393691 DOI: 10.1080/10408444.2018.1429386] [Citation(s) in RCA: 115] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 12/11/2017] [Accepted: 01/03/2018] [Indexed: 10/18/2022]
Abstract
Skin sensitization is a toxicity endpoint of widespread concern, for which the mechanistic understanding and concurrent necessity for non-animal testing approaches have evolved to a critical juncture, with many available options for predicting sensitization without using animals. Cosmetics Europe and the National Toxicology Program Interagency Center for the Evaluation of Alternative Toxicological Methods collaborated to analyze the performance of multiple non-animal data integration approaches for the skin sensitization safety assessment of cosmetics ingredients. The Cosmetics Europe Skin Tolerance Task Force (STTF) collected and generated data on 128 substances in multiple in vitro and in chemico skin sensitization assays selected based on a systematic assessment by the STTF. These assays, together with certain in silico predictions, are key components of various non-animal testing strategies that have been submitted to the Organization for Economic Cooperation and Development as case studies for skin sensitization. Curated murine local lymph node assay (LLNA) and human skin sensitization data were used to evaluate the performance of six defined approaches, comprising eight non-animal testing strategies, for both hazard and potency characterization. Defined approaches examined included consensus methods, artificial neural networks, support vector machine models, Bayesian networks, and decision trees, most of which were reproduced using open source software tools. Multiple non-animal testing strategies incorporating in vitro, in chemico, and in silico inputs demonstrated equivalent or superior performance to the LLNA when compared to both animal and human data for skin sensitization.
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Affiliation(s)
- Nicole C. Kleinstreuer
- NIH/NIEHS/DNTP/NICEATM, P.O. Box 12233, Mail Stop K2-16, Research Triangle Park, NC, 27709, USA; NK, 1-919-541-7997,; WC, 1-919-316-4729,
| | - Sebastian Hoffmann
- seh consulting + services, Stembergring 15, 33106 Paderborn, Germany; +4952518700566;
| | - Nathalie Alépée
- L’Oréal Research & Innovation, Aulnay-sous-Bois, France; NA, ; SM-T,
| | - David Allen
- ILS, P.O. Box 13501, Research Triangle Park, NC, 27709, USA, 1-919-281-1110; DA, ; JS, ; QZ,
| | - Takao Ashikaga
- Shiseido, 2-2-1, Hayabuchi, Tsuzuki-ku, Yokohama-shi, Kanagawa 224-8558, Japan. Current Address: Japanese Center for the Validation of Alternative Methods (JaCVAM), National Institute of Health Sciences (NIHS) 1-18-1 Kamiyoga, Setagaya, Tokyo, Japan;
| | - Warren Casey
- NIH/NIEHS/DNTP/NICEATM, P.O. Box 12233, Mail Stop K2-16, Research Triangle Park, NC, 27709, USA; NK, 1-919-541-7997,; WC, 1-919-316-4729,
| | - Elodie Clouet
- Pierre Fabre, 3 Avenue Hubert Curien, 31100 Toulouse, France;
| | - Magalie Cluzel
- LVMH, 185 avenue de Verdun, 45804 St Jean de Braye, France;
| | - Bertrand Desprez
- Cosmetics Europe, Avenue Herrmann Debroux 40, 1160 Brussels, Belgium; BD, ; MK,
| | - Nichola Gellatly
- Unilever, Colworth Science Park, Bedford, United Kingdom. Current address: NC3Rs, Gibbs Building, 215 Euston Road, London NW1 2BE, United Kingdom;
| | | | - Petra S. Kern
- Procter & Gamble Services Company NV, Temselaan 100, 1853 Strombeek-Bever, Belgium;
| | - Martina Klaric
- Cosmetics Europe, Avenue Herrmann Debroux 40, 1160 Brussels, Belgium; BD, ; MK,
| | - Jochen Kühnl
- Beiersdorf AG, Unnastraße 48, 20245 Hamburg, Germany;
| | | | - Karsten Mewes
- Henkel AG & Co. KGaA, Henkelstraße 67, 40589 Düsseldorf, Germany; KM, ; DP,
| | - Masaaki Miyazawa
- Kao Corporation, 2606 Akabane, Ichikai, Haga, Tochigi, 321-3497, Japan;
| | - Judy Strickland
- ILS, P.O. Box 13501, Research Triangle Park, NC, 27709, USA, 1-919-281-1110; DA, ; JS, ; QZ,
| | - Erwin van Vliet
- Services & Consultations on Alternative Methods (SeCAM), Via Campagnora 1, 6983, Magliaso, Switzerland;
| | - Qingda Zang
- ILS, P.O. Box 13501, Research Triangle Park, NC, 27709, USA, 1-919-281-1110; DA, ; JS, ; QZ,
| | - Dirk Petersohn
- Henkel AG & Co. KGaA, Henkelstraße 67, 40589 Düsseldorf, Germany; KM, ; DP,
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Parkinson E, Aleksic M, Cubberley R, Kaur-Atwal G, Vissers JPC, Skipp P. Determination of Protein Haptenation by Chemical Sensitizers Within the Complexity of the Human Skin Proteome. Toxicol Sci 2018; 162:429-438. [PMID: 29267982 PMCID: PMC5889026 DOI: 10.1093/toxsci/kfx265] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Skin sensitization associated with the development of allergic contact dermatitis occurs via a number of specific key events at the cellular level. The molecular initiating event (MIE), the first in the sequence of these events, occurs after exposure of the skin to an electrophilic chemical, causing the irreversible haptenation of proteins within skin. Characterization of this MIE is a key step in elucidating the skin sensitization adverse outcome pathway and is essential to providing parameters for mathematical models to predict the capacity of a chemical to cause sensitization. As a first step to addressing this challenge, we have exposed complex protein lysates from a keratinocyte cell line and human skin tissue with a range of well characterized sensitizers, including dinitrochlorobenzene, 5-chloro-2-methylisothiazol-3-one, cinnamaldehyde, and the non (or weak) sensitizer 6-methyl coumarin. Using a novel stable isotope labeling approach combined with ion mobility-assisted data independent mass spectrometry (HDMSE), we have characterized the haptenome for these sensitizers. Although a significant proportion of highly abundant proteins were haptenated, we also observed the haptenation of low abundant proteins by all 3 of the chemical sensitizers tested, indicating that within a complex protein background, protein abundance is not the sole determinant driving haptenation, highlighting a relationship to tertiary protein structure and the amino acid specificity of these chemical sensitizers and sensitizer potency.
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Affiliation(s)
- Erika Parkinson
- Centre for Biological Sciences
- Centre for Proteomic Research, Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, UK
| | - Maja Aleksic
- Safety & Environmental Assurance Centre, Unilever, Colworth Science Park, Sharnbrook MK44 1LQ, UK
| | - Richard Cubberley
- Safety & Environmental Assurance Centre, Unilever, Colworth Science Park, Sharnbrook MK44 1LQ, UK
| | | | | | - Paul Skipp
- Centre for Biological Sciences
- Centre for Proteomic Research, Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, UK
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Chung H, Quan H, Jung D, Ravi G, Cho A, Kang MJ, Kim E, Che J, Lee E, Jeong TC, Heo Y, Seok SH. Intra- and inter-laboratory reproducibility and predictivity of the HaCaSens assay: A skin sensitization test using human keratinocytes, HaCaT. Toxicol In Vitro 2018; 46:304-12. [DOI: 10.1016/j.tiv.2017.10.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Revised: 09/25/2017] [Accepted: 10/16/2017] [Indexed: 11/20/2022]
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Vinken M, Knapen D, Vergauwen L, Hengstler JG, Angrish M, Whelan M. Adverse outcome pathways: a concise introduction for toxicologists. Arch Toxicol 2017; 91:3697-3707. [PMID: 28660287 DOI: 10.1007/s00204-017-2020-z] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 06/22/2017] [Indexed: 12/14/2022]
Abstract
Adverse outcome pathways (AOPs) are designed to provide a clear-cut mechanistic representation of critical toxicological effects that propagate over different layers of biological organization from the initial interaction of a chemical with a molecular target to an adverse outcome at the individual or population level. Adverse outcome pathways are currently gaining momentum, especially in view of their many potential applications as pragmatic tools in the fields of human toxicology, ecotoxicology, and risk assessment. A number of guidance documents, issued by the Organization for Economic Cooperation and Development, as well as landmark papers, outlining best practices to develop, assess and use AOPs, have been published in the last few years. The present paper provides a synopsis of the main principles related to the AOP framework for the toxicologist less familiar with this area, followed by two case studies relevant for human toxicology and ecotoxicology.
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Affiliation(s)
- Mathieu Vinken
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090, Brussels, Belgium.
| | - Dries Knapen
- Zebrafishlab, Veterinary Physiology and Biochemistry, Department of Veterinary Sciences, University of Antwerp, Universiteitsplein 1, 2610, Wilrijk, Belgium
| | - Lucia Vergauwen
- Zebrafishlab, Veterinary Physiology and Biochemistry, Department of Veterinary Sciences, University of Antwerp, Universiteitsplein 1, 2610, Wilrijk, Belgium.,Systemic Physiological and Ecotoxicological Research (SPHERE), Department of Biology, University of Antwerp, Groenenborgerlaan 171, 2020, Antwerp, Belgium
| | - Jan G Hengstler
- Leibniz Research Centre for Working Environment and Human Factors (IfADo), Technical University of Dortmund, 44139, Dortmund, Germany
| | - Michelle Angrish
- National Center for Environmental Assessment, Office of Research and Development, United States Environmental Protection Agency, Research Triangle Park, NC, 27709, USA
| | - Maurice Whelan
- European Commission, Joint Research Centre (JRC), Ispra, Italy
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LaLone CA, Ankley GT, Belanger SE, Embry MR, Hodges G, Knapen D, Munn S, Perkins EJ, Rudd MA, Villeneuve DL, Whelann M, Willett C, Zhang X, Markus H. Advancing the adverse outcome pathway framework-An international horizon scanning approach. Environ Toxicol Chem 2017; 36:1411-1421. [PMID: 28543973 PMCID: PMC6156781 DOI: 10.1002/etc.3805] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 03/22/2017] [Indexed: 05/18/2023]
Abstract
Our ability to conduct whole-organism toxicity tests to understand chemical safety has been outpaced by the synthesis of new chemicals for a wide variety of commercial applications. As a result, scientists and risk assessors are turning to mechanistically based studies to increase efficiencies in chemical risk assessment and making greater use of in vitro and in silico methods to evaluate potential environmental and human health hazards. In this context, the adverse outcome pathway (AOP) framework has gained traction in regulatory science because it offers an efficient and effective means for capturing available knowledge describing the linkage between mechanistic data and the apical toxicity end points required for regulatory assessments. A number of international activities have focused on AOP development and various applications to regulatory decision-making. These initiatives have prompted dialogue between research scientists and regulatory communities to consider how best to use the AOP framework. Although expert-facilitated discussions and AOP development have been critical in moving the science of AOPs forward, it was recognized that a survey of the broader scientific and regulatory communities would aid in identifying current limitations while guiding future initiatives for the AOP framework. To that end, a global horizon scanning exercise was conducted to solicit questions concerning the challenges or limitations that must be addressed to realize the full potential of the AOP framework in research and regulatory decision-making. The questions received fell into several broad topical areas: AOP networks, quantitative AOPs, collaboration on and communication of AOP knowledge, AOP discovery and development, chemical and cross-species extrapolation, exposure/toxicokinetics considerations, and AOP applications. Expert ranking was then used to prioritize questions for each category, where 4 broad themes emerged that could help inform and guide future AOP research and regulatory initiatives. In addition, frequently asked questions were identified and addressed by experts in the field. Answers to frequently asked questions will aid in addressing common misperceptions and will allow for clarification of AOP topics. The need for this type of clarification was highlighted with surprising frequency by our question submitters, indicating that improvements are needed in communicating the AOP framework among the scientific and regulatory communities. Overall, horizon scanning engaged the global scientific community to help identify key questions surrounding the AOP framework and guide the direction of future initiatives. Environ Toxicol Chem 2017;36:1411-1421. © 2017 SETAC.
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Affiliation(s)
- Carlie A. LaLone
- US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, Duluth, MN, USA
- Corresponding Authors: ,
| | - Gerald T. Ankley
- US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, Duluth, MN, USA
| | - Scott E. Belanger
- Environmental Safety and Sustainability, Global Product Stewardship, Mason Business Center, The Procter and Gamble Company, Mason, Ohio 45040, USA
| | - Michelle R. Embry
- ILSI Health and Environmental Sciences Institute, 1156 15th Street, NW, Suite 200, Washington, DC 20005, USA
| | - Geoff Hodges
- Safety and Environmental Assurance Centre, Unilever, Colworth Science Park, Sharnbrook, Bedfordshire, MK44 1LQ, United Kingdom
| | - Dries Knapen
- ILSI Health and Environmental Sciences Institute, 1156 15th Street, NW, Suite 200, Washington, DC 20005, USA
| | - Sharon Munn
- European Commission, Joint Research Centre (JRC), Via E. Fermi 2749, 21027 Ispra, Italy
| | - Edward J. Perkins
- European Commission, Joint Research Centre (JRC), Via E. Fermi 2749, 21027 Ispra, Italy
| | - Murray A. Rudd
- Department of Environmental Sciences, Emory College, E538 Math and Science Building, Atlanta, Georgia, USA
| | - Daniel L. Villeneuve
- US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, Duluth, MN, USA
| | - Maurice Whelann
- European Commission, Joint Research Centre (JRC), Via E. Fermi 2749, 21027 Ispra, Italy
| | - Catherine Willett
- The Humane Society of the United States, Washington, District of Columbia, USA
| | - Xiaowei Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, China
| | - Hecker Markus
- Toxicology Centre, University of Saskatchewan, Saskatoon, SK, Canada, S7N 5B3
- Corresponding Authors: ,
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Fay KA, Villeneuve DL, LaLone CA, Song Y, Tollefsen KE, Ankley GT. Practical approaches to adverse outcome pathway development and weight-of-evidence evaluation as illustrated by ecotoxicological case studies. Environ Toxicol Chem 2017; 36:1429-1449. [PMID: 28198554 PMCID: PMC6058314 DOI: 10.1002/etc.3770] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 11/14/2016] [Accepted: 02/13/2017] [Indexed: 05/20/2023]
Abstract
Adverse outcome pathways (AOPs) describe toxicant effects as a sequential chain of causally linked events beginning with a molecular perturbation and culminating in an adverse outcome at an individual or population level. Strategies for developing AOPs are still evolving and depend largely on the intended use or motivation for development and data availability. The present review describes 4 ecotoxicological AOP case studies, developed for different purposes. In each situation, creation of the AOP began in a manner determined by the initial motivation for its creation and expanded either to include additional components of the pathway or to address the domains of applicability in terms of chemical initiators, susceptible species, life stages, and so forth. Some general strategies can be gleaned from these case studies, which a developer may find to be useful for supporting an existing AOP or creating a new one. Several web-based tools that can aid in AOP assembly and evaluation of weight of evidence for scientific robustness of AOP components are highlighted. Environ Toxicol Chem 2017;36:1429-1449. © 2017 SETAC.
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Affiliation(s)
- Kellie A. Fay
- Mid Continent Ecology Division, U.S. EPA, Duluth, Minnesota
- University of Minnesota – Duluth, Duluth, Minnesota, USA
- Address correspondence to
| | | | | | - You Song
- Norwegian Institute for Water Research (NIVA), Oslo, Norway
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Silva SCT, de Almeida LA, Soares S, Grossi MF, Valente AMS, Tagliati CA. In vitro study of putative genomic biomarkers of nephrotoxicity through differential gene expression using gentamicin. Toxicol Mech Methods 2017; 27:435-441. [PMID: 28372472 DOI: 10.1080/15376516.2017.1313345] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Drug-induced nephrotoxicity is one of the most frequently observed effects in long-term pharmacotherapy. The effects of nephrotoxicity are commonly discovered later due to a lack of sensitivity in in vivo methods. Therefore, researchers have tried to develop in vitro alternative methods for early identification of toxicity. In this study, LLC-PK1 cells were exposed to gentamicin through MTT and trypan blue assay. Concentrations of 4 (low), 8 (medium) and 12 (high) mM, were used to evaluate differential gene expression. A panel of genes was selected based on gene expression changes. The search for sequences of mRNA encoding proteins previously associated with kidney damage was conducted in the databases of the National Center for Biotechnology Information (USA). RNA was extracted from the cells, and RT-qPCR was performed to evaluate differential expression profiles of the selected genes. Among the 11 analyzed genes, four proved to be differentially up-regulated in cells exposed to gentamicin: HAVcr1, caspase 3, ICAM-1 and EXOC6. According to this study's results, we suggest that these genes play an important role in the mechanism of in vitro nephrotoxicity caused by gentamicin and can be used as early in vitro biomarkers to identify nephrotoxicity when developing safer drugs.
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Affiliation(s)
- Sarah Cristina Teixeira Silva
- a Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia, Laboratório de Toxicologia Experimental in vitro , Universidade Federal de Minas Gerais (UFMG) , Belo Horizonte , Brazil
| | - Leonardo Augusto de Almeida
- b Departamento de Microbiologia e Imunologia, Laboratório de Imunologia, Instituto de Ciências Biomédicas , Universidade Federal de Alfenas (UniFal) , Alfenas , Brazil
| | - Stellamaris Soares
- a Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia, Laboratório de Toxicologia Experimental in vitro , Universidade Federal de Minas Gerais (UFMG) , Belo Horizonte , Brazil
| | - Marina Felipe Grossi
- a Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia, Laboratório de Toxicologia Experimental in vitro , Universidade Federal de Minas Gerais (UFMG) , Belo Horizonte , Brazil
| | - Anete Maria Santana Valente
- c Departamento de Nutrição , Universidade Federal de Juiz de Fora (UFJF) - Campus Governador Valadares , Governador Valadares , Brazil
| | - Carlos Alberto Tagliati
- a Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia, Laboratório de Toxicologia Experimental in vitro , Universidade Federal de Minas Gerais (UFMG) , Belo Horizonte , Brazil
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Oakes T, Popple AL, Williams J, Best K, Heather JM, Ismail M, Maxwell G, Gellatly N, Dearman RJ, Kimber I, Chain B. The T Cell Response to the Contact Sensitizer Paraphenylenediamine Is Characterized by a Polyclonal Diverse Repertoire of Antigen-Specific Receptors. Front Immunol 2017; 8:162. [PMID: 28261218 PMCID: PMC5311069 DOI: 10.3389/fimmu.2017.00162] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 01/31/2017] [Indexed: 01/07/2023] Open
Abstract
Paraphenylenediamine (PPD) is a common component of hair dyes and black henna tattoos and can cause skin sensitization and allergic contact dermatitis (ACD). The cutaneous inflammatory reaction associated with ACD is driven by both CD4+ and CD8+ T cells. However, the characteristics of such responses with respect to clonal breadth and magnitude are poorly defined. In this study, we have characterized the in vitro recall response of peripheral blood T cells prepared from PPD-allergic individuals to a PPD–human serum albumin (HSA) conjugate (PPD–HSA). Quantitative high throughput sequencing was used to characterize the changes in the repertoire of T cell receptor (TCR) α and β genes after exposure to antigen in vitro. The PPD conjugate induced expansion of T cells carrying selected TCRs, with around 800 sequences (around 1%) being 8 or more times as abundant after culture than before. The expanded sequences showed strong skewing of V and J usage, consistent with an antigen-driven clonal expansion. The complementarity-determining region 3 sequences of the expanded TCRs could be grouped into several families of related amino acid sequence, but the overall diversity of the expanded sample was not much less than that of a random sample of the same size. The results suggest a model in which PPD–HSA conjugate stimulates a broad diversity of TCRs, with a wide range of stimulation strengths, which manifest as different degrees of in vitro expansion.
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Affiliation(s)
- Theres Oakes
- Division of Infection and Immunity, UCL , London , UK
| | - Amy Lee Popple
- Faculty of Life Sciences, University of Manchester , Manchester , UK
| | - Jason Williams
- Contact Dermatitis Investigation Unit, Salford Royal NHS Foundation Trust , Manchester , UK
| | | | | | | | - Gavin Maxwell
- Unilever Safety and Environmental Assurance Centre, Colworth Science Park , Sharnbrook , UK
| | - Nichola Gellatly
- Unilever Safety and Environmental Assurance Centre, Colworth Science Park , Sharnbrook , UK
| | - Rebecca J Dearman
- Faculty of Life Sciences, University of Manchester , Manchester , UK
| | - Ian Kimber
- Faculty of Life Sciences, University of Manchester , Manchester , UK
| | - Benny Chain
- Division of Infection and Immunity, UCL , London , UK
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Wittwehr C, Aladjov H, Ankley G, Byrne HJ, de Knecht J, Heinzle E, Klambauer G, Landesmann B, Luijten M, MacKay C, Maxwell G, Meek MEB, Paini A, Perkins E, Sobanski T, Villeneuve D, Waters KM, Whelan M. How Adverse Outcome Pathways Can Aid the Development and Use of Computational Prediction Models for Regulatory Toxicology. Toxicol Sci 2017; 155:326-336. [PMID: 27994170 PMCID: PMC5340205 DOI: 10.1093/toxsci/kfw207] [Citation(s) in RCA: 112] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Efforts are underway to transform regulatory toxicology and chemical safety assessment from a largely empirical science based on direct observation of apical toxicity outcomes in whole organism toxicity tests to a predictive one in which outcomes and risk are inferred from accumulated mechanistic understanding. The adverse outcome pathway (AOP) framework provides a systematic approach for organizing knowledge that may support such inference. Likewise, computational models of biological systems at various scales provide another means and platform to integrate current biological understanding to facilitate inference and extrapolation. We argue that the systematic organization of knowledge into AOP frameworks can inform and help direct the design and development of computational prediction models that can further enhance the utility of mechanistic and in silico data for chemical safety assessment. This concept was explored as part of a workshop on AOP-Informed Predictive Modeling Approaches for Regulatory Toxicology held September 24-25, 2015. Examples of AOP-informed model development and its application to the assessment of chemicals for skin sensitization and multiple modes of endocrine disruption are provided. The role of problem formulation, not only as a critical phase of risk assessment, but also as guide for both AOP and complementary model development is described. Finally, a proposal for actively engaging the modeling community in AOP-informed computational model development is made. The contents serve as a vision for how AOPs can be leveraged to facilitate development of computational prediction models needed to support the next generation of chemical safety assessment.
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Affiliation(s)
| | | | - Gerald Ankley
- US Environmental Protection Agency, Duluth, Minnesota 55804
| | | | - Joop de Knecht
- National Institute for Public Health and the Environment (RIVM), Bilthoven, MA 3721, The Netherlands
| | - Elmar Heinzle
- Universität des Saarlandes, 66123 Saarbrücken, Germany
| | | | | | - Mirjam Luijten
- National Institute for Public Health and the Environment (RIVM), Bilthoven, MA 3721, The Netherlands
| | - Cameron MacKay
- Unilever Safety and Environmenta Assurance Centre, Sharnbrook, MK44 1LQ, UK
| | - Gavin Maxwell
- Unilever Safety and Environmenta Assurance Centre, Sharnbrook, MK44 1LQ, UK
| | | | - Alicia Paini
- European Commission, Joint Research Centre, Ispra 21027, Italy
| | - Edward Perkins
- US Army Engineer Research and Development Center, Vicksburg, Mississippi 39180
| | | | - Dan Villeneuve
- US Environmental Protection Agency, Duluth, Minnesota 55804
| | - Katrina M Waters
- Pacific Northwest National Laboratory, Richland, Washington 99352
| | - Maurice Whelan
- European Commission, Joint Research Centre, Ispra 21027, Italy
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29
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Affiliation(s)
- David W. Roberts
- School
of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool L3 3AF, United Kingdom
| | - Aynur Aptula
- Unilever
Safety
and Environmental Assurance Centre, Colworth Science Park, Sharnbrook, Bedford MK44 1LQ, United Kingdom
| | - Anne Marie Api
- Research Institute for Fragrance Materials, Inc., 50 Tice Boulevard, Woodcliff
Lake, New Jersey 07677, United States
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30
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Abstract
The adverse outcome pathway (AOP) framework provides an alternative to traditional in vivo experiments for the risk assessment of chemicals. AOPs consist of a number of key events (KEs) linked by key event relationships across a range of biological organization backed by scientific evidence. The first KE in the pathway is the molecular initiating event (MIE)-the initial chemical trigger that starts an AOP. Over the past 3 years the AOP conceptual framework has gained a large amount of momentum in toxicology as an alternative to animal methods, and so the MIE has come into the spotlight. What is an MIE? How can MIEs be measured or predicted? What research is currently contributing to our understanding of MIEs? In this Perspective we outline answers to these key questions.
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Affiliation(s)
- Timothy E H Allen
- Centre for Molecular Informatics, Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Jonathan M Goodman
- Centre for Molecular Informatics, Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Steve Gutsell
- Unilever Safety and Environmental Assurance Centre , Colworth Science Park, Sharnbrook, Bedfordshire MK44 1LQ, United Kingdom
| | - Paul J Russell
- Unilever Safety and Environmental Assurance Centre , Colworth Science Park, Sharnbrook, Bedfordshire MK44 1LQ, United Kingdom
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31
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Ezendam J, Braakhuis HM, Vandebriel RJ. State of the art in non-animal approaches for skin sensitization testing: from individual test methods towards testing strategies. Arch Toxicol 2016; 90:2861-2883. [PMID: 27629427 DOI: 10.1007/s00204-016-1842-4] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 08/29/2016] [Indexed: 11/28/2022]
Abstract
The hazard assessment of skin sensitizers relies mainly on animal testing, but much progress is made in the development, validation and regulatory acceptance and implementation of non-animal predictive approaches. In this review, we provide an update on the available computational tools and animal-free test methods for the prediction of skin sensitization hazard. These individual test methods address mostly one mechanistic step of the process of skin sensitization induction. The adverse outcome pathway (AOP) for skin sensitization describes the key events (KEs) that lead to skin sensitization. In our review, we have clustered the available test methods according to the KE they inform: the molecular initiating event (MIE/KE1)-protein binding, KE2-keratinocyte activation, KE3-dendritic cell activation and KE4-T cell activation and proliferation. In recent years, most progress has been made in the development and validation of in vitro assays that address KE2 and KE3. No standardized in vitro assays for T cell activation are available; thus, KE4 cannot be measured in vitro. Three non-animal test methods, addressing either the MIE, KE2 or KE3, are accepted as OECD test guidelines, and this has accelerated the development of integrated or defined approaches for testing and assessment (e.g. testing strategies). The majority of these approaches are mechanism-based, since they combine results from multiple test methods and/or computational tools that address different KEs of the AOP to estimate skin sensitization potential and sometimes potency. Other approaches are based on statistical tools. Until now, eleven different testing strategies have been published, the majority using the same individual information sources. Our review shows that some of the defined approaches to testing and assessment are able to accurately predict skin sensitization hazard, sometimes even more accurate than the currently used animal test. A few defined approaches are developed to provide an estimate of the potency sub-category of a skin sensitizer as well, but these approaches need further independent evaluation with a new dataset of chemicals. To conclude, this update shows that the field of non-animal approaches for skin sensitization has evolved greatly in recent years and that it is possible to predict skin sensitization hazard without animal testing.
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Affiliation(s)
- Janine Ezendam
- Department of Innovative Testing Strategies, Center for Health Protection, National Institute for Public Health and the Environment (RIVM), PO Box 1, 3720 BA, Bilthoven, The Netherlands.
| | - Hedwig M Braakhuis
- Department of Innovative Testing Strategies, Center for Health Protection, National Institute for Public Health and the Environment (RIVM), PO Box 1, 3720 BA, Bilthoven, The Netherlands
| | - Rob J Vandebriel
- Department of Innovative Testing Strategies, Center for Health Protection, National Institute for Public Health and the Environment (RIVM), PO Box 1, 3720 BA, Bilthoven, The Netherlands
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Perkins EJ, Antczak P, Burgoon L, Falciani F, Garcia-Reyero N, Gutsell S, Hodges G, Kienzler A, Knapen D, McBride M, Willett C. Adverse Outcome Pathways for Regulatory Applications: Examination of Four Case Studies With Different Degrees of Completeness and Scientific Confidence. Toxicol Sci 2016; 148:14-25. [PMID: 26500288 DOI: 10.1093/toxsci/kfv181] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Adverse outcome pathways (AOPs) offer a pathway-based toxicological framework to support hazard assessment and regulatory decision-making. However, little has been discussed about the scientific confidence needed, or how complete a pathway should be, before use in a specific regulatory application. Here we review four case studies to explore the degree of scientific confidence and extent of completeness (in terms of causal events) that is required for an AOP to be useful for a specific purpose in a regulatory application: (i) Membrane disruption (Narcosis) leading to respiratory failure (low confidence), (ii) Hepatocellular proliferation leading to cancer (partial pathway, moderate confidence), (iii) Covalent binding to proteins leading to skin sensitization (high confidence), and (iv) Aromatase inhibition leading to reproductive dysfunction in fish (high confidence). Partially complete AOPs with unknown molecular initiating events, such as 'Hepatocellular proliferation leading to cancer', were found to be valuable. We demonstrate that scientific confidence in these pathways can be increased though the use of unconventional information (eg, computational identification of potential initiators). AOPs at all levels of confidence can contribute to specific uses. A significant statistical or quantitative relationship between events and/or the adverse outcome relationships is a common characteristic of AOPs, both incomplete and complete, that have specific regulatory uses. For AOPs to be useful in a regulatory context they must be at least as useful as the tools that regulators currently possess, or the techniques currently employed by regulators.
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Affiliation(s)
- Edward J Perkins
- *Environmental Laboratory, US Army Engineer Research and Development Center, Vicksburg Mississippi;
| | - Philipp Antczak
- Institute of Integrative Biology, University of Liverpool, Liverpool, Merseyside L69 3BX, UK
| | - Lyle Burgoon
- *Environmental Laboratory, US Army Engineer Research and Development Center, Vicksburg Mississippi
| | - Francesco Falciani
- Institute of Integrative Biology, University of Liverpool, Liverpool, Merseyside L69 3BX, UK
| | - Natàlia Garcia-Reyero
- Mississippi State University, Institute for Genomics, Biocomputing and Biotechnology, Starkville, Mississippi
| | - Steve Gutsell
- Unilever, Colworth Science Park, Sharnbrook MK44 1LQ, UK
| | - Geoff Hodges
- Unilever, Colworth Science Park, Sharnbrook MK44 1LQ, UK
| | - Aude Kienzler
- JRC Institute for Health and Consumer Protection, Ispra, Italy
| | - Dries Knapen
- University of Antwerp, Zebrafishlab, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Mary McBride
- Agilent Technologies, Washington, District of Columbia; and
| | - Catherine Willett
- The Humane Society of the United States, Washington, District of Columbia, USA
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33
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Spriggs S, Sheffield D, Olayanju A, Kitteringham NR, Naisbitt DJ, Aleksic M. Effect of Repeated Daily Dosing with 2,4-Dinitrochlorobenzene on Glutathione Biosynthesis and Nrf2 Activation in Reconstructed Human Epidermis. Toxicol Sci 2016; 154:5-15. [PMID: 27492222 DOI: 10.1093/toxsci/kfw140] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Glutathione (GSH) plays a major role in skin detoxification processes due to its ability to conjugate electrophilic exogenous compounds with, and sometimes without, catalysis by glutathione-s-transferase (GST). GST activity has been demonstrated both in skin and in most in vitro skin equivalents but so far studies have focussed on chemical clearance (conjugate identification and rate of conjugation) and did not consider the GSH lifecycle (conjugation, recycling, synthesis). We used the model skin sensitizer 2,4-dinitrochlorobenzene (DNCB) to investigate the effects of chemical exposure on GSH lifecycle in reconstructed human epidermis (RHE). We demonstrated that the RHE model is suitable to carry out repeated cycles of 2-h exposure to DNCB over a 3-day period. After each exposure to DNCB, the level of GSH is diminished in a dose dependent manner. After a 22-h recovery period, GSH is replenished back to initial levels. Accumulation of the nuclear factor E2-related factor 2 (Nrf2) in the cytosol also occurs within the 2 h of exposure to DNCB but returns to baseline during each recovery period, demonstrating that activation of the Nrf2 signaling pathway offers a rapid response to chemical stress. The amount of dinitrophenyl-glutathione (DNP-SG) formed with DNCB (1) increased between the first and second exposure and (2) reached a plateau between the second and third exposure. Collectively, these data suggest that the metabolic capacity of skin may not be fixed in time but defence mechanisms might be activated in response to exposure to exogenous compounds, resulting in their accelerated clearance.
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Affiliation(s)
- Sandrine Spriggs
- *Unilever, Safety and Environmental Assurance Centre, Colworth Science Park, Sharnbrook, Bedfordshire MK44 1LQ, UK;
| | - David Sheffield
- *Unilever, Safety and Environmental Assurance Centre, Colworth Science Park, Sharnbrook, Bedfordshire MK44 1LQ, UK
| | - Adedamola Olayanju
- Department of Molecular and Clinical Pharmacology, MRC Centre for Drug Safety Science, the University of Liverpool, Sherrington Building, Ashton Street, Liverpool L69 3GE, UK
| | - Neil R Kitteringham
- Department of Molecular and Clinical Pharmacology, MRC Centre for Drug Safety Science, the University of Liverpool, Sherrington Building, Ashton Street, Liverpool L69 3GE, UK
| | - Dean J Naisbitt
- Department of Molecular and Clinical Pharmacology, MRC Centre for Drug Safety Science, the University of Liverpool, Sherrington Building, Ashton Street, Liverpool L69 3GE, UK
| | - Maja Aleksic
- *Unilever, Safety and Environmental Assurance Centre, Colworth Science Park, Sharnbrook, Bedfordshire MK44 1LQ, UK
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34
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Roberts DW, Api AM, Aptula AO. Chemical applicability domain of the Local Lymph Node Assay (LLNA) for skin sensitisation potency. Part 2. The biological variability of the murine Local Lymph Node Assay (LLNA) for skin sensitisation. Regul Toxicol Pharmacol 2016; 80:255-9. [PMID: 27470439 DOI: 10.1016/j.yrtph.2016.07.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 07/19/2016] [Accepted: 07/21/2016] [Indexed: 12/14/2022]
Abstract
The Local Lymph Node Assay (LLNA) is the most common in vivo regulatory toxicology test for skin sensitisation, quantifying potency as the EC3, the concentration of chemical giving a threefold increase in thymidine uptake in the local lymph node. Existing LLNA data can, along with clinical data, provide useful comparator information on the potency of sensitisers. Understanding of the biological variability of data from LLNA studies is important for those developing non-animal based risk assessment approaches for skin allergy. Here an existing set of 94 EC3 values for 12 chemicals, all tested at least three times in the same vehicle have been analysed by calculating standard deviations (SD) for logEC3 values. The SDs range from 0.08 to 0.22. The overall SD for the 94 logEC3 values is 0.147. Thus the 95% confidence limits (2xSD) for LLNA EC3 values are within a factor of 2, comparable to those for physico-chemical measurements such as partition coefficients and solubility. The residual SDs of Quantitative Mechanistic Models (QMMs) based on physical organic chemistry parameters are similar to the overall SD of the LLNA, indicating that QMMs of this type are unlikely to be bettered for predictive accuracy.
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35
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Gust KA, Collier ZA, Mayo ML, Stanley JK, Gong P, Chappell MA. Limitations of toxicity characterization in life cycle assessment: Can adverse outcome pathways provide a new foundation? Integr Environ Assess Manag 2016; 12:580-590. [PMID: 26331849 DOI: 10.1002/ieam.1708] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 05/05/2015] [Accepted: 08/20/2015] [Indexed: 06/05/2023]
Abstract
Life cycle assessment (LCA) has considerable merit for holistic evaluation of product planning, development, production, and disposal, with the inherent benefit of providing a forecast of potential health and environmental impacts. However, a technical review of current life cycle impact assessment (LCIA) methods revealed limitations within the biological effects assessment protocols, including: simplistic assessment approaches and models; an inability to integrate emerging types of toxicity data; a reliance on linear impact assessment models; a lack of methods to mitigate uncertainty; and no explicit consideration of effects in species of concern. The purpose of the current study is to demonstrate that a new concept in toxicological and regulatory assessment, the adverse outcome pathway (AOP), has many useful attributes of potential use to ameliorate many of these problems, to expand data utility and model robustness, and to enable more accurate and defensible biological effects assessments within LCIA. Background, context, and examples have been provided to demonstrate these potential benefits. We additionally propose that these benefits can be most effectively realized through development of quantitative AOPs (qAOPs) crafted to meet the needs of the LCIA framework. As a means to stimulate qAOP research and development in support of LCIA, we propose 3 conceptual classes of qAOP, each with unique inherent attributes for supporting LCIA: 1) mechanistic, including computational toxicology models; 2) probabilistic, including Bayesian networks and supervised machine learning models; and 3) weight of evidence, including models built using decision-analytic methods. Overall, we have highlighted a number of potential applications of qAOPs that can refine and add value to LCIA. As the AOP concept and support framework matures, we see the potential for qAOPs to serve a foundational role for next-generation effects characterization within LCIA. Integr Environ Assess Manag 2016;12:580-590. Published 2015. This article is a US Government work and is in the public domain in the USA.
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Affiliation(s)
- Kurt A Gust
- US Army Engineer Research & Development Center, Vicksburg, Mississippi
| | - Zachary A Collier
- US Army Engineer Research & Development Center, Vicksburg, Mississippi
| | - Michael L Mayo
- US Army Engineer Research & Development Center, Vicksburg, Mississippi
| | - Jacob K Stanley
- US Army Engineer Research & Development Center, Vicksburg, Mississippi
| | - Ping Gong
- US Army Engineer Research & Development Center, Vicksburg, Mississippi
| | - Mark A Chappell
- US Army Engineer Research & Development Center, Vicksburg, Mississippi
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36
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Dumont C, Barroso J, Matys I, Worth A, Casati S. Analysis of the Local Lymph Node Assay (LLNA) variability for assessing the prediction of skin sensitisation potential and potency of chemicals with non-animal approaches. Toxicol In Vitro 2016; 34:220-228. [PMID: 27085510 DOI: 10.1016/j.tiv.2016.04.008] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 03/22/2016] [Accepted: 04/12/2016] [Indexed: 11/29/2022]
Abstract
The knowledge of the biological mechanisms leading to the induction of skin sensitisation has favoured in recent years the development of alternative non-animal methods. During the formal validation process, results from the Local Lymph Node Assay (LLNA) are generally used as reference data to assess the predictive capacity of the non-animal tests. This study reports an analysis of the variability of the LLNA for a set of chemicals for which multiple studies are available and considers three hazard classification schemes: POS/NEG, GHS/CLP and ECETOC. As the type of vehicle used in a LLNA study is known to influence to some extent the results, two analyses were performed: considering the solvent used to test the chemicals and without considering the solvent. The results show that the number of discordant classifications increases when a chemical is tested in more than one solvent. Moreover, it can be concluded that study results leading to classification in the strongest classes (1A and EXT) seem to be more reliable than those in the weakest classes. This study highlights the importance of considering the variability of the reference data when evaluating non-animal tests.
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Affiliation(s)
- Coralie Dumont
- Joint Research Centre, European Commission, Ispra, Italy
| | - João Barroso
- Joint Research Centre, European Commission, Ispra, Italy
| | - Izabela Matys
- Joint Research Centre, European Commission, Ispra, Italy
| | - Andrew Worth
- Joint Research Centre, European Commission, Ispra, Italy
| | - Silvia Casati
- Joint Research Centre, European Commission, Ispra, Italy.
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37
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38
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Abstract
In this chapter, we explain how Integrated Approaches to Testing and Assessment (IATA) offer a means of integrating and translating the data generated by toxicity testing methods, thereby serving as flexible and suitable tools for toxicological decision making in the twenty-first century. In addition to traditional in vitro and in vivo testing methods, IATA are increasingly incorporating newly developed in vitro systems and measurement technologies such as high throughput screening and high content imaging. Computational approaches are also being used in IATA development, both as a means of generating data (e.g. QSARs), interpreting data (bioinformatics and chemoinformatics), and as a means of integrating multiple sources of data (e.g. expert systems, bayesian models). Decision analytic methods derived from socioeconomic theory can also play a role in developing flexible and optimal IATA solutions. Some of the challenges involved in the development, validation and implementation of IATA are also discussed.
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39
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Gong P, Hong H, Perkins EJ. Ionotropic GABA receptor antagonism-induced adverse outcome pathways for potential neurotoxicity biomarkers. Biomark Med 2015; 9:1225-39. [PMID: 26508561 DOI: 10.2217/bmm.15.58] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Antagonism of ionotropic GABA receptors (iGABARs) can occur at three distinct types of receptor binding sites causing chemically induced epileptic seizures. Here we review three adverse outcome pathways, each characterized by a specific molecular initiating event where an antagonist competitively binds to active sites, negatively modulates allosteric sites or noncompetitively blocks ion channel on the iGABAR. This leads to decreased chloride conductance, followed by depolarization of affected neurons, epilepsy-related death and ultimately decreased population. Supporting evidence for causal linkages from the molecular to population levels is presented and differential sensitivity to iGABAR antagonists in different GABA receptors and organisms discussed. Adverse outcome pathways are poised to become important tools for linking mechanism-based biomarkers to regulated outcomes in next-generation risk assessment.
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Affiliation(s)
- Ping Gong
- Environmental Laboratory, US Army Engineer Research & Development Center, 3909 Halls Ferry Road, Vicksburg, MS 39180, USA
| | - Huixiao Hong
- Division of Bioinformatics & Biostatistics, National Center for Toxicological Research, US Food & Drug Administration, 3900 NCTR Road, Jefferson, AR 72079, USA
| | - Edward J Perkins
- Environmental Laboratory, US Army Engineer Research & Development Center, 3909 Halls Ferry Road, Vicksburg, MS 39180, USA
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40
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Luechtefeld T, Maertens A, McKim JM, Hartung T, Kleensang A, Sá-Rocha V. Probabilistic hazard assessment for skin sensitization potency by dose-response modeling using feature elimination instead of quantitative structure-activity relationships. J Appl Toxicol 2015; 35:1361-1371. [PMID: 26046447 DOI: 10.1002/jat.3172] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 04/06/2015] [Accepted: 04/13/2015] [Indexed: 01/08/2023]
Abstract
Supervised learning methods promise to improve integrated testing strategies (ITS), but must be adjusted to handle high dimensionality and dose-response data. ITS approaches are currently fueled by the increasing mechanistic understanding of adverse outcome pathways (AOP) and the development of tests reflecting these mechanisms. Simple approaches to combine skin sensitization data sets, such as weight of evidence, fail due to problems in information redundancy and high dimensionality. The problem is further amplified when potency information (dose/response) of hazards would be estimated. Skin sensitization currently serves as the foster child for AOP and ITS development, as legislative pressures combined with a very good mechanistic understanding of contact dermatitis have led to test development and relatively large high-quality data sets. We curated such a data set and combined a recursive variable selection algorithm to evaluate the information available through in silico, in chemico and in vitro assays. Chemical similarity alone could not cluster chemicals' potency, and in vitro models consistently ranked high in recursive feature elimination. This allows reducing the number of tests included in an ITS. Next, we analyzed with a hidden Markov model that takes advantage of an intrinsic inter-relationship among the local lymph node assay classes, i.e. the monotonous connection between local lymph node assay and dose. The dose-informed random forest/hidden Markov model was superior to the dose-naive random forest model on all data sets. Although balanced accuracy improvement may seem small, this obscures the actual improvement in misclassifications as the dose-informed hidden Markov model strongly reduced " false-negatives" (i.e. extreme sensitizers as non-sensitizer) on all data sets.
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Affiliation(s)
- Thomas Luechtefeld
- Johns Hopkins University, Bloomberg School of Public Health, Center for Alternatives to Animal Testing, Baltimore, MD, USA
| | - Alexandra Maertens
- Johns Hopkins University, Bloomberg School of Public Health, Center for Alternatives to Animal Testing, Baltimore, MD, USA
| | | | - Thomas Hartung
- Johns Hopkins University, Bloomberg School of Public Health, Center for Alternatives to Animal Testing, Baltimore, MD, USA.,University of Konstanz, Center for Alternatives to Animal Testing Europe, Konstanz, Germany
| | - Andre Kleensang
- Johns Hopkins University, Bloomberg School of Public Health, Center for Alternatives to Animal Testing, Baltimore, MD, USA
| | - Vanessa Sá-Rocha
- Johns Hopkins University, Bloomberg School of Public Health, Center for Alternatives to Animal Testing, Baltimore, MD, USA.,Natura Inovação, Cajamar, Brazil
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41
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Mc Auley MT, Choi H, Mooney K, Paul E, Miller VM. Systems Biology and Synthetic Biology: A New Epoch for Toxicology Research. ACTA ACUST UNITED AC 2015; 2015:1-14. [DOI: 10.1155/2015/575403] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Systems biology and synthetic biology are emerging disciplines which are becoming increasingly utilised in several areas of bioscience. Toxicology is beginning to benefit from systems biology and we suggest in the future that is will also benefit from synthetic biology. Thus, a new era is on the horizon. This review illustrates how a suite of innovative techniques and tools can be applied to understanding complex health and toxicology issues. We review limitations confronted by the traditional computational approaches to toxicology and epidemiology research, using polycyclic aromatic hydrocarbons (PAHs) and their effects on adverse birth outcomes as an illustrative example. We introduce how systems toxicology (and their subdisciplines, genomic, proteomic, and metabolomic toxicology) will help to overcome such limitations. In particular, we discuss the advantages and disadvantages of mathematical frameworks that computationally represent biological systems. Finally, we discuss the nascent discipline of synthetic biology and highlight relevant toxicological centred applications of this technique, including improvements in personalised medicine. We conclude this review by presenting a number of opportunities and challenges that could shape the future of these rapidly evolving disciplines.
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Allen TEH, Goodman JM, Gutsell S, Russell PJ. Defining Molecular Initiating Events in the Adverse Outcome Pathway Framework for Risk Assessment. Chem Res Toxicol 2014; 27:2100-12. [DOI: 10.1021/tx500345j] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Timothy E. H. Allen
- Centre
for Molecular Informatics, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Jonathan M. Goodman
- Centre
for Molecular Informatics, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Steve Gutsell
- Unilever Safety and Environmental Assurance Centre, Colworth Science Park, Sharnbrook, Bedfordshire MK44 1LQ, United Kingdom
| | - Paul J. Russell
- Unilever Safety and Environmental Assurance Centre, Colworth Science Park, Sharnbrook, Bedfordshire MK44 1LQ, United Kingdom
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Stiefel C, Schwack W. Photoprotection in changing times - UV filter efficacy and safety, sensitization processes and regulatory aspects. Int J Cosmet Sci 2014; 37:2-30. [DOI: 10.1111/ics.12165] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 09/20/2014] [Indexed: 12/14/2022]
Affiliation(s)
- C. Stiefel
- Institute of Food Chemistry; University of Hohenheim; Garbenstrasse 28 70599 Stuttgart Germany
| | - W. Schwack
- Institute of Food Chemistry; University of Hohenheim; Garbenstrasse 28 70599 Stuttgart Germany
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Affiliation(s)
- Stefan F. Martin
- Allergy Research Group, Department of Dermatology; Medical Centre - University of Freiburg; Hauptstrasse 7 D-79104 Freiburg Germany
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Parkinson E, Boyd P, Aleksic M, Cubberley R, O'Connor D, Skipp P. Stable isotope labeling method for the investigation of protein haptenation by electrophilic skin sensitizers. Toxicol Sci 2014; 142:239-49. [PMID: 25145658 DOI: 10.1093/toxsci/kfu168] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The risk of contact sensitization is a major consideration in the development of new formulations for personal care products. However, developing a mechanistic approach for non-animal risk assessment requires further understanding of haptenation of skin proteins by sensitizing chemicals, which is the molecular initiating event causative of skin sensitization. The non-stoichiometric nature of protein haptenation results in relatively low levels of modification, often of low abundant proteins, presenting a major challenge for their assignment in complex biological matrices such as skin. Instrumental advances over the last few years have led to a considerable increase in sensitivity of mass spectrometry (MS) techniques. We have combined these advancements with a novel dual-labeling/LC-MS(E) approach to provide an in-depth direct comparison of human serum albumin (HSA), 2,4-dinitro-1-chlorobenzene (DNCB), 5-chloro-2-methyl-4-isothiazolin-3-one (MCI), trans-cinnamaldehyde, and 6-methyl coumarin. These data have revealed novel insights into the differences in protein haptenation between sensitizers with different reaction mechanisms and sensitizing potency; the extreme sensitizers DNCB and MCI were shown to modify a greater number of nucleophilic sites than the moderate sensitizer cinnamaldehyde; and the weak/non-sensitizer 6-methyl coumarin was restricted to only a single nucleophilic residue within HSA. The evaluation of this dual labeling/LC-MS(E) approach using HSA as a model protein has also demonstrated that this strategy could be applied to studying global haptenation in complex mixtures of skin-related proteins by different chemicals.
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Affiliation(s)
- Erika Parkinson
- Centre for Biological Sciences, University of Southampton, Southampton, SO17 1BJ, UK Centre for Proteomic Research, Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - Pete Boyd
- Centre for Biological Sciences, University of Southampton, Southampton, SO17 1BJ, UK Centre for Proteomic Research, Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - Maja Aleksic
- Safety and Environmental Assurance Centre, Unilever, Colworth Science Park, Sharnbrook, MK44 1LQ, UK
| | - Richard Cubberley
- Safety and Environmental Assurance Centre, Unilever, Colworth Science Park, Sharnbrook, MK44 1LQ, UK
| | - David O'Connor
- Department of Biological Sciences, Xi'an Jiaotong-Liverpool University, SIP Suzhou, Jiangsu Province 215123, China
| | - Paul Skipp
- Centre for Biological Sciences, University of Southampton, Southampton, SO17 1BJ, UK Centre for Proteomic Research, Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, UK
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