Sanne Hermsen MSc
PhD Student

Field of interest: Embryotoxicity

Profile

Development of a genomics based screening method to detect embryotoxicity of compounds using the Zebrafish Embryotoxicity Assay

On the whole embryo level, the mammalian embryo culture model for the study of developmental toxicity and morphogenesis is currently the in vitro model closest to human development. However, it is restricted to a 48 hours developmental window and transgenic studies are not yet possible. The zebrafish embryo toxicity (ZET) test enables study of the complete developmental period of a vertebrate embryo in a simple and fast culture system.
First, the optimal protocol for embryotoxicity testing will be designed on the basis of existing expertise in addition to a literature survey. Aspects of interest are ambient conditions, developmental period to be studied, exposure concentration and duration, and number of eggs per exposure. Morphological endpoints will be defined and standardized. Secondly, a series of standard embryotoxicants will be tested in a dose-response design using morphological assessment as endpoint.
Since the application of genomics-based technologies including bioinformatics, in toxicological research may finally provide high throughput tools for chemical safety testing, this technique will be implemented in the ZET. The complete genome of the zebrafish has been identified and the availability of transgenic strains allows detailed studies of mechanisms of development and developmental toxicity. Gene expression studies will be initiated using zebrafish whole genome arrays as well as dedicated real-time PCR assessment of preferential genes. Gene expression will be coupled to proteomics analysis, and where possible on the basis of data analysis, specific genes will be silenced using siRNA techniques and specific reporter strains to study the role of specific genes in compound-induced maldevelopment. In addition, a larger set of chemicals known to affect embryogenesis and related non-embryotoxic controls will be tested to study the applicability domain of the test system.