Adverse outcome pathway network-based
testing strategy for thyroid disruption
Jiří Novák, Klára Hilscherová
RECETOX, Masaryk University, Kamenice 753/5, 625
00 Brno, Czech Republic
Adverse outcome pathway (AOP) concept5,6 -
a model identifying sequence of biochemical
events required to produce a toxic effect
when an organism is exposed to a substance.
AOP can provide f or:
•detailed mechanistic characteristics of
an adverse effect
•design of testing strategy by
identification of key events in the
•linking biomarkers assessed
Fig. 2 Cross-class thyroid hormone disruption AOP network
covering mammalian, amphibian and teleost endpoints
ERGO - Breaking down the wall between human health and environmental testing
of endocrine disrupters (EU Horizon2020 Topic-SC1-BHC-27-2018;
15 partners across Europe).
Main project hypothesis:
For conserved endocrine systems such as Hypothalamic
Pituitary Thyroid (HPT) axis it is feasible to extrapolate
effects of EDCs across vertebrate classes
Fig.1Overview of Adverse
Outcome Pathway (AOP)concept
Fig. 1 The three key societal impact areas of ERGOproject, which
are affected by improved ED testing and screening methods
Fig. 3 Cross-class thyroid hormone
disruption AOP network covering
mammalian, amphibian and teleost
Project aims for development of a battery of
assays (Tab. 1) and
evaluation of HPT disruption-related biomarkers suitable for extrapolation
of effects from fish and amphibian tests to humans and other mammals
Project outcome is based on data from
in silico, in vitro
1. Investigation, development and pre-validation of new thyroid-related
biomarkers for inclusion in OECD test guidelines for improved
identification of thyroid system disrupting compounds.
2. Development an adverse outcome pathway (AOP) network across
vertebrate classes for identification of thyroid B/E applicable for
assessment of cross-class thyroid disrupting key events.
3. An Integrated Approach to Testing and Assessment (IATA) of chemicals
for TD based on a multi-class vertebrate AOPs (Fig.2, 3) network
connecting endocrine mechanisms in one vertebrate class to adverse
outcomes in another class.
4. A tool for test guidelines end users, such as regulators and industry, to
extrapolate effects on thyroid regulation between vertebrate classes.
Implementation of the ERGO IATA strategy in regulations of EDC will
make hazard and risk assessment faster, cheaper, simpler and safer.
Tab. 1 Prioritized endpoints to include into
bioassay battery addressing specific
molecular initiation events (MIE) with corresponding Adverse OutcomePathways(AOP)
Ref e r en c e s :
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32, 310–31 9 (2016).
2.St in cken s, E.
et al .
An AOP-based a lt erna ti ve t esti ng st rat egy t o pred ict t he impa ct of t hyroi d hor mone disr upti on on swi m blad der i nfl at ion i n zeb raf ish.
Aqua t. T oxi col .
200, 1 –12 (201 8).
3. Ren, X. - M.
et al .
Bindinginteractionsofperfluoroalkyl substanceswiththyroidhormone transport proteinsand potential toxicological implications.
366–367, 32–42 (201 6).
4.Illés, P., Brtko, J. & Dvořák, Z. Development and Characterization of a Human Reporter Cell Line f or the Assessment of Thyroi d Receptor Transcript ional Acti vit y: A Case of Organotin Endocrine Disruptors.
J. Agr ic. Food Chem.
63, 7074–83 (2015).
5.Aopwiki. Availableat: https://aopwiki.org/. (Accessed: 18th March2019)
6.Villeneuve, D. L.
et al .
Adve rse Out come Pa th way ( AOP) Deve lopme nt I : S tr ate gi es and Pri nci pl es.
142, 312–320 (2014).
level of interaction/function of target MIE included in AOP No. model origin
Iodide transmembrane transporter Na+/I- symporter (NIS)
AOP 65, 54, 134, 176 human, rat
TH synthesis thyroperoxidase (TPO) inhibition
AOP 42,119, 159, 175, 271 human, rat, pig
TH activation/inactivation Iodothyronine deiodinase 1 (DIO1) inhibition
AOP 157, 158, 189, rat, pig
Iodothyronine deiodinase 2 (DIO2) inhibition
AOP 155, 156, 190 rat, pig
serum TH binding protein T4-TTR displacement
AOP 152 in chemico
AOP 152 in chemico
TH responses Thyroid hormone receptor antagonism
AOP 300 human