SETAC Europe 35th Annual Meeting

The development and use of an adverse outcome pathway (AOP)-informed cellular Oxidative stress NAM for hazard screening

Abstract: Oxidative stress has been described as a prominent mechanism of xenobiotic toxicity and a common denominator in many disease states yet a standalone test does not exist. The conceptual adverse outcome pathway (AOP) framework allows us to organise the key processes involved and monitor them at each level of biological organisation. Thus, a likely series of key events (KE) that leads to oxidative stress and ultimately oxidative cell death can be proposed and tested for. Oxidative stress can occur in any species from bacteria to humans, therefore, as a biomarker it has a wide domain of applicability across species. In this investigation we have used the rainbow trout fish species, Oncorhynchus mykiss, as a test model and the RTgill W1 and RTL W1 cells lines to develop such an oxidative stress AOP-informed testing strategy, focusing on monitoring upstream and downstream key events involved in its processes as well as the cells redox status. These events included increases in cellular reactive oxygen species (ROS) levels (KE 1940) and increased lipid peroxidation (KE 1445). The cellular redox status at different exposure times was characterised by monitoring levels of oxidation of glutathione (KE 926). The information from this multi-parametric NAM was integrated and in this way the intensity of an oxidative insult could be characterised into low, intermediate or high intensity. Such an approach can be used to help interpret data from multiple assays, for hazard ranking or indeed to group substances based on their oxidative stress potential. Property-effect relationships can then be established for these different reactivity groups to identify the descriptors that can be linked to such reactivity and used in a predictive toxicology space. This developed NAM was applied when testing the hazard of multi-component mixed metal oxide perovskites. As a benchmark material a CuO nanomaterial was included, for which there is large evidence of oxidative stress association. To provide in vivo anchorage levels of these key events, biomarkers were also assessed in tissues of perovskite exposed fish. Data generated from such cellular based NAMs can be used in weight of evidence (WoE) approaches for hazard assessment and for hazard screening in safe and sustainable by design (SSbD) strategies.

Disclaimer/ Disclosure (optional): Acknowledgements: HARMLESS grant agreement No. 953183 and General protocol of actions between MITECO and INIA, CSIC for carrying out activities related to substances and chemical mixtures.

Author(s):

Mona Connolly National Institute for Agricultural and Food Research and Technology (INIA), CSIC Spain

Elena García Sánchez Universidad de Alcalá (UAH) Madrid Spain

María Jiménez Lara National Institute for Agricultural and Food Research and Technology (INIA), CSIC Spain

Stefany Mendoza Burgos Universidad Autónoma de Madrid Spain

Gerardo Pulido Reyes Universidad Autónoma de Madrid Spain

José María Navas National Institute for Agricultural and Food Research and Technology (INIA), CSIC Spain This Author Is the Presenter