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.
Abbreviations
- ADME:
-
Absorption, distribution, metabolism, and excretion
- AEP:
-
Aggregate exposure pathway
- AO(s):
-
Adverse outcome(s)
- AOP(s):
-
Adverse outcome pathway(s)
- AOP-KB:
-
Adverse outcome pathway knowledge base
- ARE:
-
Anti-oxidant response element
- DPRA:
-
Direct peptide reactivity assay
- E2:
-
17-Beta-estradiol
- EPA:
-
Environmental Protection Agency
- FELS:
-
Fish early life-stage
- GPMT:
-
Guinea pig maximization test
- hCLAT:
-
Human cell line activation test
- HPG:
-
Hypothalamic–pituitary–gonadal
- IATA:
-
Integrated approaches to testing and assessment
- JRC:
-
Joint Research Centre of the European Commission
- Keap1/Nrf2:
-
Kelch-like ECH-associated protein 1/nuclear erythroid 2-related factor
- KE(R):
-
Key event (relationship)
- LLNA:
-
Local lymph node assay
- MIE:
-
Molecular initiating event
- MUSST:
-
Myeloid U937 skin sensitization test
- OECD:
-
Organization for Economic Cooperation and Development
- QSAR:
-
Quantitative structure–activity relationship
- REACH:
-
Registration, Evaluation, Authorization, and Restriction of Chemicals
- SETAC:
-
Society of Environmental Toxicology and Chemistry
- VTG:
-
Vitellogenin
References
Ankley GT, Bencic DC, Cavallin JE, Jensen KM, Kahl MD, Makynen EA, Martinovic D, Mueller ND, Wehmas LC, Villeneuve DL (2009) Dynamic nature of alterations in the endocrine system of fathead minnows exposed to the fungicide prochloraz. Toxicol Sci 112:344–353
Ankley GT, Bennett RS, Erickson RJ, Hoff DJ, Hornung MW, Johnson RD, Mount DR, Nichols JW, Russom CL, Schmieder PK, Serrrano JA, Tietge JE, Villeneuve DL (2010) Adverse outcome pathways: a conceptual framework to support ecotoxicology research and risk assessment. Environ Toxicol Chem 29:730–741
Ashikaga T, Yoshida Y, Hirota M, Yoneyama K, Itagaki H, Sakaguchi H, Miyazawa M, Ito Y, Suzuki H, Toyoda H (2006) Development of an in vitro skin sensitization test using human cell lines: the human cell line activation test (h-CLAT): I. Optimization of the h-CLAT protocol. Toxicol In Vitro 20:767–773
Basketter DA, White IR, McFadden JP, Kimber I (2015) Skin sensitization: implications for integration of clinical data into hazard identification and risk assessment. Hum Exp Toxicol 34:1222–1230
Becker RA, Ankley GT, Edwards SW, Kennedy SW, Linkov I, Meek B, Sachana M, Segner H, Van Der Burg B, Villeneuve DL, Watanabe H, Barton-Maclaren TS (2015) Increasing scientific confidence in adverse outcome pathways: application of tailored Bradford-Hill considerations for evaluating weight of evidence. Regul Toxicol Pharmacol 72:514–537
Bell SM, Angrish MM, Wood CE, Edwards SW (2016) Integrating publicly available data to generate computationally predicted adverse outcome pathways for fatty liver. Toxicol Sci 150:510–520
Boobis AR, Cohen SM, Dellarco V, McGregor D, Meek ME, Vickers C, Willcocks D, Farland W (2006) IPCS framework for analyzing the relevance of a cancer mode of action for humans. Crit Rev Toxicol 36:781–792
Boobis AR, Doe JE, Heinrich-Hirsch B, Meek ME, Munn S, Ruchirawat M, Schlatter J, Seed J, Vickers C (2008) IPCS framework for analyzing the relevance of a noncancer mode of action for humans. Crit Rev Toxicol 38:87–96
Burden N, Sewell F, Andersen ME, Boobis A, Chipman JK, Cronin MT, Hutchinson TH, Kimber I, Whelan M (2015) Adverse outcome pathways can drive non-animal approaches for safety assessment. J Appl Toxicol 35:971–975
Cheng WY, Zhang Q, Schroeder A, Villeneuve DL, Ankley GT, Conolly R (2016) Computational modeling of plasma vitellogenin alterations in response to aromatase inhibition in fathead minnows. Toxicol Sci 154:78–89
Collier ZA, Gust KA, Gonzalez-Morales B, Gong P, Wilbanks MS, Linkov I, Perkins EJ (2016) A weight of evidence assessment approach for adverse outcome pathways. Regul Toxicol Pharmacol 75:46–57
Conolly RB, Ankley GT, Cheng W, Mayo ML, Miller DH, Perkins EJ, Villeneuve DL, Wantanbe KH (2017) Quantitative adverse outcome pathways and their application to predictive toxicology. Environ Sci Technol 51:4661–4672
Dean JL, Jay Zhao Q, Lambert JC, Hawkins BS, Thomas RS, Wesselkamper SC (2017) Application of gene set enrichment analysis for identification of chemically-induced, biologically relevant transcriptomic networks and potential utilization in human health risk assessment. Toxicol Sci. doi:10.1093/toxsci/kfx021
Dellarco VL, Wiltse JA (1998) US Environmental Protection Agency’s revised guidelines for Carcinogen Risk Assessment: incorporating mode of action data. Mutat Res 405:273–277
Delrue N, Sachana M, Sakuratani Y, Gourmelon A, Leinala E, Diderich R (2016) The adverse outcome pathway concept: a basis for developing regulatory decision-making tools. Altern Lab Anim 44:417–429
Edwards SW, Tan YM, Villeneuve DL, Meek ME, McQueen CA (2016) Adverse outcome pathways: organizing toxicological information to improve decision making. J Pharmacol Exp Ther 356:170–181
Emter R, Ellis G, Natsch A (2010) Performance of a novel keratinocyte-based reporter cell line to screen skin sensitizers in vitro. Toxicol Appl Pharmacol 245:281–290
EPA (2017) https://www.epa.gov/chemical-research/adverse-outcome-pathway-aop-research-brief (consulted April 2017)
Ezendam J, Braakhuis HM, Vandebriel RJ (2016) State of the art in non-animal approaches for skin sensitization testing: from individual test methods towards testing strategies. Arch Toxicol 90:2861–2883
Gerberick GF, Vassallo JD, Bailey RE, Chaney JG, Morrall SW, Lepoittevin JP (2004) Development of a peptide reactivity assay for screening contact allergens. Toxicol Sci 81:332–343
Hill AB (1965) The environment and disease: association or causation? Proc R Soc Med 58:295–300
Hinfray N, Porcher JM, Brion F (2006) Inhibition of rainbow trout (Oncorhynchus mykiss) P450 aromatase activities in brain and ovarian microsomes by various environmental substances. Comp Biochem Physiol C 144:252–262
http://aopkb.org/ (consulted April 2017)
https://www.qsartoolbox.org/ (consulted April 2017)
Kimber I, Mitchell JA, Griffin AC (1986) Development of a murine local lymph node assay for the determination of sensitizing potential. Food Chem Toxicol 24:585–586
Knapen D, Vergauwen L, Villeneuve DL, Ankley GT (2015) The potential of AOP networks for reproductive and developmental toxicity assay development. Reprod Toxicol 56:52–55
LaLone CA, Ankley GT, Belanger SE, Embry MR, Hodges G, Knapen D, Munn S, Perkins EJ, Rudd MA, Villeneuve DL, Whelan M, Willett C, Zhang X, Hecker M (2017) Advancing the adverse outcome pathway framework: an international horizon scanning approach. Environ Toxicol Chem 36:1411–1421
Li ZH, Villeneuve DL, Jensen KM, Ankley GT, Watanabe KH (2011) A computational model for asynchronous oocyte growth dynamics in a batch-spawning fish. Can J Fish Aquat Sci 68:1528–1538
Magnusson B, Kligman AM (1969) The identification of contact allergens by animal assay: the Guinea pig maximization test. J Invest Dermatol 52:268–276
Maxwell G, MacKay C, Cubberley R, Davies M, Gellatly N, Glavin S, Gouin T, Jacquoilleot S, Moore C, Pendlington R, Saib O, Sheffield D, Stark R, Summerfield V (2014) Applying the skin sensitisation adverse outcome pathway (AOP) to quantitative risk assessment. Toxicol In Vitro 28:8–12
Meek ME, Boobis A, Cote I, Dellarco V, Fotakis G, Munn S, Seed J, Vickers C (2014a) New developments in the evolution and application of the WHO/IPCS framework on mode of action/species concordance analysis. J Appl Toxicol 34:1–18
Meek ME, Palermo CM, Bachman AN, North CM, Jeffrey Lewis R (2014b) Mode of action human relevance (species concordance) framework: evolution of the Bradford-Hill considerations and comparative analysis of weight of evidence. J Appl Toxicol 34:595–606
Miller DH, Ankley GT (2004) Modeling impacts on populations: fathead minnow (Pimephales promelas) exposure to the endocrine disruptor 17 beta-trenbolone as a case study. Ecotoxicol Environ Saf 59:1–9
Miller DH, Jensen KM, Villeneuve DL, Kahl MD, Makynen EA, Durhan EJ, Ankley GT (2007) Linkage of biochemical responses to population-level effects: a case study with vitellogenin in the fathead minnow (Pimephales promelas). Environ Toxicol Chem 26:521–527
Nelson K, Schroeder A, Ankley G, Blackwell B, Blanksma C, Degitz S, Flynn K, Jensen K, Johnson R, Kahl M, Knapen D, Kosian PA, Milsk RY, Randolph EC, Saari T, Stinckens E, Vergauwen L, Villeneuve DL (2016) Impaired anterior swim bladder inflation following exposure to the thyroid peroxidase inhibitor 2-mercaptobenzothiazole part I: fathead minnow. Aquat Toxicol 173:192–203
NRC (2007) Toxicity testing in the 21st century: a vision and a strategy. The National Academies Press, Washington, DC
OECD (2012) OECD series on testing and assessment number 168: the adverse outcome pathway for skin sensitization initiated by covalent binding to proteins part 1: scientific evidence ENV/JM/MONO(2012) 10/PART1. OECD Publishing, Paris
OECD (2013) OECD series on testing and assessment number 184: guidance document on developing and assessing adverse outcome pathways ENV/JM/MONO(2013)6. OECD Publishing, Paris
OECD (2014) The adverse outcome pathway for skin sensitisation initiated by covalent binding to proteins. OECD Publishing, Paris
OECD (2016) OECD series on adverse outcome pathways number 1: users’ handbook supplement to the guidance document for developing and assessing adverse outcome pathways. OECD Publishing, Paris
Oki NO, Edwards SW (2016) An integrative data mining approach to identifying adverse outcome pathway signatures. Toxicology 350–352:49–61
Oki NO, Nelms MD, Bell SM, Mortensen HM, Edwards SW (2016) Accelerating adverse outcome pathway development using publicly available data sources. Curr Environ Health Rep 3:53–63
Patlewicz G, Kuseva C, Kesova A, Popova I, Zhechev T, Pavlov T, Roberts DW, Mekenyan O (2014) Towards AOP application: implementation of an integrated approach to testing and assessment (IATA) into a pipeline tool for skin sensitization. Regul Toxicol Pharmacol 69:529–545
Patlewicz G, Simon TW, Rowlands JC, Budinsky RA, Becker RA (2015) Proposing a scientific confidence framework to help support the application of adverse outcome pathways for regulatory purposes. Regul Toxicol Pharmacol 71:463–477
Paul KB, Hedge JM, Macherla C, Filer DL, Burgess E, Simmons SO, Crofton KM, Hornung MW (2013) Cross-species analysis of thyroperoxidase inhibition by xenobiotics demonstrates conservation of response between pig and rat. Toxicology 312:97–107
Paul KB, Hedge JM, Rotroff DM, Hornung MW, Crofton KM, Simmons SO (2014) Development of a thyroperoxidase inhibition assay for high-throughput screening. Chem Res Toxicol 27:387–399
Perkins EJ, Antczak P, Burgoon L, Falciani F, Garcia-Reyero N, Gutsell S, Hodges G, Kienzler A, Knapen D, McBride M, Willett C (2015) Adverse outcome pathways for regulatory applications: examination of four case studies with different degrees of completeness and scientific confidence. Toxicol Sci 148:14–25
Preston RJ, Williams GM (2005) DNA-reactive carcinogens: mode of action and human cancer hazard. Crit Rev Toxicol 35:673–683
Python F, Goebel C, Aeby P (2007) Assessment of the U937 cell line for the detection of contact allergens. Toxicol Appl Pharmacol 220:113–124
Ramirez T, Mehling A, Kolle SN, Wruck CJ, Teubner W, Eltze T, Aumann A, Urbisch D, van Ravenzwaay B, Landsiedel R (2014) LuSens: a keratinocyte based ARE reporter gene assay for use in integrated testing strategies for skin sensitization hazard identification. Toxicol In Vitro 28:1482–1497
Richard AM, Judson RS, Houck KA, Grulke CM, Volarath P, Thillainadarajah I, Yang CH, Rathman J, Martin MT, Wambaugh JF, Knudsen TB, Kancherla J, Mansouri K, Patlewicz G, Williams AJ, Little SB, Crofton KM, Thomas RS (2016) ToxCast chemical landscape: paving the road to 21st century toxicology. Chem Res Toxicol 29:1225–1251
Sakaguchi H, Ashikaga T, Miyazawa M, Yoshida Y, Ito Y, Yoneyama K, Hirota M, Itagaki H, Toyoda H, Suzuki H (2006) Development of an in vitro skin sensitization test using human cell lines: human cell line activation test (h-CLAT): II. An interlaboratory study of the h-CLAT. Toxicol In Vitro 20:774–784
Sonich-Mullin C, Fielder R, Wiltse J, Baetcke K, Dempsey J, Fenner-Crisp P, Grant D, Hartley M, Knaap A, Kroese D, Mangelsdorf I, Meek ME, Rice J, Younes M (2001) IPCS conceptual framework for evaluating a mode of action for chemical carcinogenesis. Regul Toxicol Pharmacol 34:146–152
Stinckens E, Vergauwen L, Schroeder AL, Maho W, Blackwell BR, Witters H, Blust R, Ankley GT, Covaci A, Villeneuve DL, Knapen D (2016) Impaired anterior swim bladder inflation following exposure to the thyroid peroxidase inhibitor 2-mercaptobenzothiazole part II: zebrafish. Aquat Toxicol 173:204–217
Teeguarden JG, Tan YM, Edwards SW, Leonard JA, Anderson KA, Corley RA, Kile ML, Simonich SM, Stone D, Tanguay RL, Waters KM, Harper SL, Williams DE (2016) Completing the link between exposure science and toxicology for improved environmental health decision making: the aggregate exposure pathway framework. Environ Sci Technol 50:4579–4586
Tollefsen KE, Scholz S, Cronin MT, Edwards SW, de Knecht J, Crofton K, Garcia-Reyero N, Hartung T, Worth A, Patlewicz G (2014) Applying adverse outcome pathways (AOPs) to support integrated approaches to testing and assessment (IATA). Regul Toxicol Pharmacol 70:629–640
Urbisch D, Mehling A, Guth K, Ramirez T, Honarvar N, Kolle S, Landsiedel R, Jaworska J, Kern PS, Gerberick F, Natsch A, Emter R, Ashikaga T, Miyazawa M, Sakaguchi H (2015) Assessing skin sensitization hazard in mice and men using non-animal test methods. Regul Toxicol Pharmacol 71:337–351
Villeneuve DL (2016) Adverse outcome pathway on aromatase inhibition leading to reproductive dysfunction (in fish). OECD series on adverse outcome pathways, vol 4. OECD Publishing, Paris
Villeneuve DL, Mueller ND, Martinovic D, Makynen EA, Kahl MD, Jensen KM, Durhan EJ, Cavallin JE, Bencic D, Ankley GT (2009) Direct effects, compensation, and recovery in female fathead minnows exposed to a model aromatase inhibitor. Environ Health Perspect 117:624–631
Villeneuve DL, Crump D, Garcia-Reyero N, Hecker M, Hutchinson TH, LaLone CA, Landesmann B, Lettieri T, Munn S, Nepelska M, Ottinger MA, Vergauwen L, Whelan M (2014a) Adverse outcome pathway (AOP) development I: strategies and principles. Toxicol Sci 142:312–320
Villeneuve DL, Crump D, Garcia-Reyero N, Hecker M, Hutchinson TH, LaLone CA, Landesmann B, Lettieri T, Munn S, Nepelska M, Ottinger MA, Vergauwen L, Whelan M (2014b) Adverse outcome pathway development II: best practices. Toxicol Sci 142:321–330
Villeneuve DL, Volz DC, Embry MR, Ankley GT, Belanger SE, Leonard M, Schirmer K, Tanguay R, Truong L, Wehmas L (2014c) Investigating alternatives to the fish early-life stage test: a strategy for discovering and annotating adverse outcome pathways for early fish development. Environ Toxicol Chem 33:158–169
Wang CC, Lin YC, Wang SS, Shih C, Lin YH, Tung CW (2017) SkinSensDB: a curated database for skin sensitization assays. J Cheminform 9:5
Wiltse JA, Dellarco VL (2000) U.S. Environmental Protection Agency’s revised guidelines for carcinogen risk assessment: evaluating a postulated mode of carcinogenic action in guiding dose-response extrapolation. Mutat Res 464:105–115
Wittwehr C, Aladjov H, Ankley G, Byrne HJ, de Knecht J, Heinzle E, Klambauer G, Landesmann B, Luijten M, MacKay C, Maxwell G, Meek ME, Paini A, Perkins E, Sobanski T, Villeneuve D, Waters KM, Whelan M (2017) How adverse outcome pathways can aid the development and use of computational prediction models for regulatory toxicology. Toxicol Sci 155:326–336
Acknowledgements
This work was supported by the grants of the European Research Council (ERC Starting Grant 335476), the Fund for Scientific Research-Flanders (FWO Grants G009514N, G010214N, and G051117N), the University Hospital of the Vrije Universiteit Brussel-Belgium (Willy Gepts Fonds UZ-VUB) and the Cefic Long-range Research Initiative Project LRI-ECO20.2 with support of ECETOC. The authors would like to thank Dr. Steve Edwards, Dr. Dan Villeneuve and Dr. John Vandenberg for their technical peer review.
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Vinken, M., Knapen, D., Vergauwen, L. et al. Adverse outcome pathways: a concise introduction for toxicologists. Arch Toxicol 91, 3697–3707 (2017). https://doi.org/10.1007/s00204-017-2020-z
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DOI: https://doi.org/10.1007/s00204-017-2020-z