Markers of Murine Embryonic and Neural Stem Cells, Neurons and Astrocytes: Reference Points for Developmental Neurotoxicity Testing

University of Konstanz, Germany.
ALTEX 01/2010; 27(1):17-42.
Source: PubMed


Developmental neurotoxicity (DNT) is a serious concern for environmental chemicals, as well as for food and drug constituents. Animal-based DNT models have relatively low sensitivity, and they are burdened by high work-load, cost and animal ethics. Murine embryonic stem cells (mESC) recapitulate several critical processes involved in the development of the nervous system if they are induced to differentiate into neural cells. They therefore represent an alternative toxicological model to predict human hazard. In this review, we discuss how mESC can be used for DNT assays. We have compiled a list of mRNA markers that define undifferentiated mESC (n = 42), neural stem cells (n = 73), astrocytes (n = 25) and the pattern of different neuronal and non-neuronal cell types generated (n = 57). We propose that transcriptional profiling can be used as a sensitive endpoint in toxicity assays to distinguish neural differentiation states during normal and disturbed development. Importantly, we believe that it can be scaled up to relatively high throughput whilst still providing rich information on disturbances affecting small cell subpopulations. Moreover, this approach can provide insight into underlying mechanisms and pathways of toxicity. We broadly discuss the methodological basis of marker lists and DNT assay design. The discussion is put in the context of a new generation of alternative assays (embryonic stem cell based DNT testing = ESDNT V2.0), that may later include human induced pluripotent stem cells, and that are not designed for 1:1 replacement of animal experiments, but are rather intended to improve human risk assessment by using independent scientific principles.

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Available from: Bastian Zimmer
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    • "Other cell identifier genes are upregulated during the cellular maturation phase. Such waves of transcriptional changes are also found in differentiating embryonic stem cells (ESC) [1]. They are guided and controlled by chromatin structure, which regulates the accessibility of the underlying DNA to sequence-specific regulator proteins such as transcription factors (TFs) or the transcriptional initiation complex [2]. "
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    ABSTRACT: Despite an abundance of studies on chromatin states and dynamics, there is an astonishing dearth of information on the expression of genes responsible for regulating histone and DNA modifications. We used here a set of 156 defined epigenetic modifier genes (EMG) and profiled their expression pattern in cells of different lineages. As reference value, expression data from human embryonic stem cells (hESC) were used. Hepatocyte-like cells were generated from hESC, and their EMG expression was compared to primary human liver cells. In parallel, we generated postmitotic human neurons (Lu d6), and compared their relative EMG expression to human cortex (Ctx). Clustering analysis of all cell types showed that neuronal lineage samples grouped together (94 similarly regulated EMG), as did liver cells (61 similarly-regulated), while the two lineages were clearly distinct. The general classification was followed by detailed comparison of the major EMG groups; genes that were higher expressed in differentiated cells than in hESC included the acetyltransferase KAT2B and the methyltransferase SETD7. Neuro-specific EMGs were the histone deacetylases HDAC5 and HDAC7, and the arginine-methyltransferase PRMT8. Comparison of young (Lu d6) and more aged (Ctx) neuronal samples suggested a maturation-dependent switch in the expression of functionally homologous proteins. For instance, the ratio of the histone H3 K27 methyltransfereases, EZH1 to EZH2, was high in Ctx and low in Lu d6. The same was observed for the polycomb repressive complex 1 (PRC1) subunits CBX7 and CBX8. A large proportion of EMGs in differentiated cells was very differently expressed than in hESC, and absolute levels were significantly higher in neuronal samples than in hepatic cells. Thus, there seem to be distinct qualitative and quantitative differences in EMG expression between cell lineages.
    Full-text · Article · Jul 2014 · PLoS ONE
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    • "Systems are used to a limited extent for prescreens Breier et al. (2010); Moser (2011) Neurons from embryonal carcinoma stem cells and ESCs -Stem-cell-based protocols are the focus of current industrial initiatives Kuegler et al. (2010); Coyne et al. (2011) V. Ahuja and S. Sharma "
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    ABSTRACT: Early assessment of the toxicity potential of new molecules in pharmaceutical industry is a multi-dimensional task involving predictive systems and screening approaches to aid in the optimization of lead compounds prior to their entry into development phase. Due to the high attrition rate in the pharma industry in last few years, it has become imperative for the nonclinical toxicologist to focus on novel approaches which could be helpful for early screening of drug candidates. The need is that the toxicologists should change their classical approach to a more investigative approach. This review discusses the developments that allow toxicologists to anticipate safety problems and plan ways to address them earlier than ever before. This includes progress in the field of in vitro models, surrogate models, molecular toxicology, 'omics' technologies, translational safety biomarkers, stem-cell based assays and preclinical imaging. The traditional boundaries between teams focusing on efficacy/ safety and preclinical/ clinical aspects in the pharma industry are disappearing, and translational research-centric organizations with a focused vision of bringing drugs forward safely and rapidly are emerging. Today's toxicologist should collaborate with medicinal chemists, pharmacologists, and clinicians and these value-adding contributions will change traditional toxicologists from side-effect identifiers to drug development enablers. Copyright © 2013 John Wiley & Sons, Ltd.
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    • "While there is no deus ex machina to solve all these challenges for the experimental toxicologist , the advent of pluripotent stem cells (PSCs) provides significant improvements (Baquié et al. 2012; Leist et al. 2008), enabling the impact of potentially toxic pesticides to be studied on virtually all types of cells without recourse to immortalized cell lines. Within the last 5 years, the European ESNATS consortium has been developing pluripotent stem cell-based toxicity tests, and first results demonstrate that such test systems may indeed become powerful tools (Krug et al. 2013; Bolt 2013; Vojnits et al. 2012; Kern et al. 2013; Meganathan et al. 2012; Kuegler et al. 2010; Zimmer et al. 2011a, b; Balmer et al. 2012). "

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