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Modeling of neural differentiation by using embryonic stem cells to detect developmental toxicants

Modeling of neural differentiation by using embryonic stem cells to detect developmental toxicants

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ZIMMER, Bastian, 2011. Modeling of neural differentiation by using embryonic stem cells to detect developmental toxicants [Dissertation]. Konstanz: University of Konstanz

@phdthesis{Zimmer2011Model-17392, title={Modeling of neural differentiation by using embryonic stem cells to detect developmental toxicants}, year={2011}, author={Zimmer, Bastian}, address={Konstanz}, school={Universität Konstanz} }

Zimmer, Bastian Developmental disabilities and congenital malformations associated with neural development are increasing problems in western countries. More and more evidence emerges from human epidemiological studies that environmental chemicals as well as drug and food constituents contribute to such an increase. Unfortunately, developmental neurotoxicity is currently the least examined form of developmental toxicity. Less then 200 compounds worldwide, mostly pesticides, have been tested in vivo according to the OECD test guideline TG 426. This guideline requires expensive and labor intensive animal experiments which often lack human relevance. As embryonic stem cells are able to differentiate into every cell type of an organism and have been shown to recapitulate in vivo development in the culture dish, they are considered a powerful alternative to whole animal experiments. Since also human embryonic stem cells have been generated, it is possible to mimic effects of chemicals on human neural development in vitro today. In the framework of this doctoral thesis, we used murine and human embryonic stem cells to establish basic concepts of in vitro developmental toxicity testing and to develop new test systems based on these cells.<br /><br />In a first step, we characterized and modified a published 2-step neural differentiation protocol based on mouse ESC to fulfill the requirements of an in vitro toxicity test system. By using whole genome transciptome analysis we were able to identify different waves of gene expression. In a second step, we correlated these waves of gene expression with important steps of neural development. Proof-of-principle experiments showed that the waves identified could be the basis for endpoint selection and exposure windows. In the next step, we analyzed the effects of low-dose chronic methylmercury exposure on late neuronal differentiation. We identified dopaminergic neurons as relevant targets of mercury toxicity. We thereby were the first to correlate gene expression findings with functional readouts in an embryonic stem cell based in vitro developmental neurotoxicity test system. Additionally, we were able to correlate in-cell toxicant concentrations with relevant in vivo concentrations in such a setting. After having established the principles important for embryonic stem cell based developmental neurotoxicity testing, we developed a neural crest migration assay based on cells differentiated from human embryonic stem cells. We found that these cells detected adverse effects on cell migration, an important process during neural development, in a more sensitive way than non- neural cell lines. These findings contribute to the development of embryonic stem cell based in vitro assays and have set general principles on what needs to be assessed in such assays. deposit-license Modeling of neural differentiation by using embryonic stem cells to detect developmental toxicants 2013-12-01T23:25:04Z Zimmer, Bastian 2011-12-19T13:19:06Z 2011 eng

Dateiabrufe seit 01.10.2014 (Informationen über die Zugriffsstatistik)

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