Teratogen screening using transcriptome profiling of differentiating human embryonic stem cells.
Bottom Line: To examine teratogenic effects on early human development we performed non-biased expression profiling of differentiating human embryonic and induced pluripotent stem cells treated with several drugs--ethanol, lithium, retinoic acid (RA), caffeine and thalidomide, which is known to be highly species specific.Our results point to the potency of specific teratogens and their affected tissues and pathways.Specifically, we could show that ethanol caused dramatic increase in endodermal differentiation, RA caused misregulation of neural development and thalidomide affected both these processes.
Affiliation: Department of Genetics, Silberman Institute of Life Sciences, The Hebrew University, Jerusalem, Israel.Show MeSH
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Mentions: To further characterize the molecular events induced by ethanol, RA and thalidomide, Gene Ontology based functional annotation was performed  (Fig. 2). Of the categories enriched in genes up-regulated by RA are the homeobox protein genes (14.1-fold above expected frequency). Hox genes of the Homeobox gene family are key regulators of many developmental processes and are known to be directly regulated by RA signalling . Hox genes have been shown to be expressed in vertebrates along the dorsal axis in a spatially and temporally regulated manner, such that the 3′ located genes are expressed earlier and in the anterior regions, while the 5′ located genes are expressed later on and in the posterior parts of the embryo. In our analysis we show that the anterior HoxA and HoxB genes are specifically up-regulated by RA treatment both in HESC and HiPSC EBs (Fig. 3A). In the ethanol treated EBs the most significantly up-regulated functional group were liver protein genes (9.3-fold) (Fig. 2). These include several apolipoprotein and fibrinogen genes (Fig. 3B) as well as the early hepatic markers AFP and transthyretin. Later adult hepatic markers such as albumin and the alcohol dehydrogenase genes were not up-regulated. Thalidomide caused significant up-regulation of genes responsible for metabolism of xenobiotics (11.5-fold) and down-regulation of oxidative stress response genes (15.8-fold). This observation fits with previous reports connecting thalidomide activity with reactive oxygen species induced DNA damage. Additionally affected were several developmental related gene groups such as nervous system development genes (2.5-fold) and transforming growth factor β genes (29.6-fold) (Fig. 2).
Affiliation: Department of Genetics, Silberman Institute of Life Sciences, The Hebrew University, Jerusalem, Israel.