GenoSHIFT

Genotoxicity of chemical compounds is of high-concern in toxicology, and thus for human, animal and environmental health. Among short-term tests developed to assess the genotoxicity of compounds, the micronucleus (MN) assay is largely recognized as a reliable and precise method for detecting chromosomal damage. MN assay is indeed a multi-target genotoxic endpoint (for ex. by taking into account the presence or absence of centromeres), allowing the assessment of clastogenic and aneugenic events. The assay is amenable for automation and allows good extrapolation for potential limits of exposure, with easy measurement both in vitro and in vivo. If in vivo assays are particularly useful to characterize the effects of metabolites, new integrated models are needed to reduce the number of rodents in toxicity tests. In addition, classic MN assay does not provide a dynamic assessment of mode-of-action (MoA) and long term effects, requiring the analysis of multiple exposure times especially for chronic exposures. We propose to bring innovation in the field of MN assay for hazard assessment of potential mutagens/carcinogens, by developing a multi-parametric in vitro MN assay. The Genoshift consortium aims at associating i) a metabolically-competent hepatic cell line (HepaRP), expressing a patented biotracer of the chromatin (chromatibody), optimized and associated to an inflammation reporter gene with ii) a high-content screening imaging approach for MN formation, but also for alternative genetic endpoints and cell parameters, in order to iii) refine genotoxic information and integrate them to multiOMICs data (transcriptomics and metabolomics) and iv) better characterize and subclassify genotoxic compounds, alone or in combination, particularly for subchronic exposure. As proof-of-concept, we will revisit the genotoxic compounds listed by ECVAM. This approach will help and refine specific signatures and MoA to, in the long term, predict or anticipate mixture or cocktail effects, for genotoxic compounds or other toxicants for which chronic exposure at very low doses are challenging questions. This innovative approach will be completed by a toxicokinetic alternative endpoint, as an intestinal barrier model (intestinal organoïds cultivated in 2D), will be integrated to the final system. All partners engaged in the project have high-level of expertise, both technically and scientifically. Each stage of the assay development is based on partners' skills, cutting the risk for the project. The Genoshift project, associating applied research and research transfer, aims to deliver an integrated assay able to answer today’s genotoxicity experts recommendations, based on mode-of-actions, with significant improvements in the scientific, technical and socio-economical parameters. On socio-economical aspects, the assay offers an alternative to in vivo experiments and allows a direct and automated MN read-out, cutting the coast of classic MN assays. In addition, instead of developing a brand new genotoxic assay, it brings innovative betterment to an already recognized assay. On the technic and scientific side, the project is in line with OECD’s guidelines and experts recommendations, allowing to give insights on the genotoxic mechanisms/mode-of-actions, and determine/classify the genotoxic potential of substances/contaminants, in vitro and in real-time, even for chronic exposure. For that matter, the Genoshift project may impact many fields, from human/animal health to environmental aspects, and lead to progress in prevention and/or diagnosis of exposure to compounds. Overall, the Genoshift project aims to a better safety -regarding all chemicals, drugs and additives- with regard to exposure of humans, farm animals/pets and environment.