Investigation of mixture effects of pesticides in vitro (Combiomics)

11/2013-10/2015

This third-party funded project is conducted in the framework of the BfR research program for modern methods in toxicology.

Support code of the Federal Ministry of Education and Research: FKZ 031A267A

In this BMBF-collaborative project led by the BfR, Department Pesticides Safety, together with the University of Veterinary Medicine, Institute for Food Toxicology and Chemical Analytics, Hannover (TiHo) and the University Bielefeld, Center for Biotechnology (CeBiTec) combination effects of pesticides are analyzed in vitro.

Consumers are constantly exposed to chemical mixtures e. g. to multiple residues of different pesticides via the diet. This raises questions concerning potential cumulative effects, especially for substances causing toxicity by a common mode of action. Since substances are tested for regulatory purposes on an individual basis at generally high dose levels, there is only limited data available on potential mixture effects especially in the low dose range. Hence toxicological investigation of combined effects of substances represents a key challenge to current experimental and regulatory toxicology. The development of in vitro tools for the assessment of mixture effects is of tremendous importance as 1) with more than 400 active substances approved for being used in pesticides and over 100000 chemicals registered under REACH there are more possible combinations than one could test with classical animal experiments and 2) the nature of combination toxicity (i. e. simple similar action, interaction) strongly depends on the mechanism of action of individual substances which is poorly addressed in standard toxicity tests and therefore requires molecular methods that allow insight into mechanistic events.

In the Combiomics-project, potential mixture effects are identified upon a group of widely used and well characterized fungicides: triazoles. They are known to cause liver toxicity and endocrine disruption by a common mode of action. Therefore, this project focuses on the analysis of a set of cell lines from endocrine-related organs and from liver by parallel collecting and subsequently integrating data from multiple ‘omics’ levels as a basis for systems biology prediction. Based on data from analyses of the transcriptome, proteome and metabolome of cells treated with single substances, a prediction model for the effects of mixtures of substances will be developed. The suitability of the prediction model will be reviewed and optimized using data from mixtures of triazoles. In a next step a validation with further substances is planned and the prediction model shall be extended to different substance groups of pesticides and to further substance classes to facilitate the comprehensive assessment of combination effects in vitro. Since recent European regulations for plant protection products and biocides require that combination toxicity should be analysed, the successful establishment of a tissue based in vitro model for the analysis and prediction of combination effects would have the potential to avoid an enormous increase in animal testing.