Articles by Stefanie Klima in JoVE
Human Pluripotent Stem Cell Based Developmental Toxicity Assays for Chemical Safety Screening and Systems Biology Data Generation Vaibhav Shinde*1, Stefanie Klima*2, Perumal Srinivasan Sureshkumar1, Kesavan Meganathan1, Smita Jagtap1, Eugen Rempel3, Jörg Rahnenführer3, Jan Georg Hengstler4, Tanja Waldmann2, Jürgen Hescheler1, Marcel Leist*2, Agapios Sachinidis*1 1Center of Physiology and Pathophysiology, Institute of Neurophysiology, University of Cologne, 2Department of Biology, University of Konstanz, 3Department of Statistics, Technical University of Dortmund, 4Leibniz Research Centre for Working Environment and Human Factors, Technical University of Dortmund The protocols describe two in vitro developmental toxicity test systems (UKK and UKN1) based on human embryonic stem cells and transcriptome studies. The test systems predict human developmental toxicity hazard, and may contribute to reduce animal studies, costs and the time required for chemical safety testing.
Other articles by Stefanie Klima on PubMed
From Transient Transcriptome Responses to Disturbed Neurodevelopment: Role of Histone Acetylation and Methylation As Epigenetic Switch Between Reversible and Irreversible Drug Effects Archives of Toxicology. Jul, 2014 | Pubmed ID: 24935251 The superordinate principles governing the transcriptome response of differentiating cells exposed to drugs are still unclear. Often, it is assumed that toxicogenomics data reflect the immediate mode of action (MoA) of drugs. Alternatively, transcriptome changes could describe altered differentiation states as indirect consequence of drug exposure. We used here the developmental toxicants valproate and trichostatin A to address this question. Neurally differentiating human embryonic stem cells were treated for 6 days. Histone acetylation (primary MoA) increased quickly and returned to baseline after 48 h. Histone H3 lysine methylation at the promoter of the neurodevelopmental regulators PAX6 or OTX2 was increasingly altered over time. Methylation changes remained persistent and correlated with neurodevelopmental defects and with effects on PAX6 gene expression, also when the drug was washed out after 3-4 days. We hypothesized that drug exposures altering only acetylation would lead to reversible transcriptome changes (indicating MoA), and challenges that altered methylation would lead to irreversible developmental disturbances. Data from pulse-chase experiments corroborated this assumption. Short drug treatment triggered reversible transcriptome changes; longer exposure disrupted neurodevelopment. The disturbed differentiation was reflected by an altered transcriptome pattern, and the observed changes were similar when the drug was washed out during the last 48 h. We conclude that transcriptome data after prolonged chemical stress of differentiating cells mainly reflect the altered developmental stage of the model system and not the drug MoA. We suggest that brief exposures, followed by immediate analysis, are more suitable for information on immediate drug responses and the toxicity MoA.