Project description:This study provides a comprehensive evaluation of changes in gene expression during treatment with environmental chemicals in embryonic bodies derived from mouse embryonic stem (ES) cells. ES cells were maintained under the feeder cells in phenol red-free DMEM Medium (supplemented with 15% FBS, 100uM Non-essential amino acids (NEAA), 1000U/ml Leukemia inhibitory factor(LIF), 100uM 2-mercaptoethanol(2-ME), and 0.5% penicillin/streptomycin). Cells were gently washed in warm PBS and transferred to phenol red-free DMEM Medium (supplemented with 15% KnockOut Serum Replacement, 100uM NEAA, 100uM 2-ME, and 0.5% penicillin/streptomycin) in Microsphere array (MSA300F) and exposed with low and high levels of each chemical just after removing LIF from the culture media. Prior to collection, cells were washed in warm PBS, resuspended and briefly incubated in the QIAGEN RLT buffer, and finally collected in triplicate at 48 hours. Following RNA isolation, the best RNA yields for each replicate set was selected for target preparation and microarray processing.
Project description:We performed an untargeted metabolomic analysis on surficial human skin samples collected with moistened cotton swabs (water: ethanol, 50:50) using LC-HR-MS/MS. Data-dependent Acquisition was employed under positive ionization mode. Two cohorts were included, subjects exposed and non-exposed to petroleum-based chemicals.
Project description:To develop molecular indicators of neurodevelopmental disorders related to the exposure to external chemicals, we have employed whole genome microarray expression profiling as a discovery platform to identify genes with the potential to influence neuronal differentiation from embryonic stem cells. Thalidomide (TMD), bisphenol A (BPA), 4-hydroxy-2,2',3,4',5,5',6-heptachlorobiphenyl (4OH-PCB187) and 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) were exposed to human embryonic stem (ES) cell-derived sphere on day 3 after starting sphere formation for 72 hours. Gene expression analysis on the stage of sphere development showed chemical specific characteristics.
Project description:Sall4 is a transcription factor essential for early mammalian development. Though it is reported to play an important role in embryonic stem (ES) cell self-renewal, whether it is an essential pluripotency factor has been disputed. Though Sall4 is known to associate with the Nucleosome Remodeling and Deacetylase (NuRD) complex, the nature of this interaction is unclear as NuRD and Sall4 serve opposing functions in ES cells. Here we use defined culture conditions and single-cell gene expression analyses to show that Sall4 prevents activation of the neural gene expression programme in ES cells but is dispensable for maintaining the pluripotency gene regulatory network. We further show using genome-wide analyses that while Sall4 interacts with NuRD, it neither recruits NuRD to chromatin nor influences transcription via NuRD. Rather we propose a model where, by titrating Sall4 protein, NuRD limits the differentiation-inhibiting activity of Sall4 in ES cells to enable lineage commitment.
Project description:We chronically exposed HepaRG (differentiated hepatic cells that retain primary human hepatocytes characteristics) and HepaG2 (liver hepatocarcinoma cells) liver cells to physiologically relevant concentrations of Cadmiun and PFOAs chemicals (10nM) to observed how these affect global gene expression in these cellular models.
Project description:The excitement and controversy surrounding the potential role of human embryonic stem (ES) cells in transplantation therapy have often overshadowed their potentially more important use as a basic research tool for understanding the development and function of human tissues. Human ES cells can proliferate without a known limit and can form advanced derivatives of all three embryonic germ layers. What is less widely appreciated is that human ES cells can also form the extra-embryonic tissues that differentiate from the embryo before gastrulation. The use of human ES cells to derive early human trophoblast is particularly valuable, because it is difficult to obtain from other sources and is significantly different from mouse trophoblast. Here we show that bone morphogenetic protein 4 (BMP4), a member of the transforming growth factor-beta (TGF-beta) superfamily, induces the differentiation of human ES cells to trophoblast. DNA microarray, RT-PCR, and immunoassay analyses demonstrate that the differentiated cells express a range of trophoblast markers and secrete placental hormones. When plated at low density, the BMP4-treated cells form syncytia that express chorionic gonadotrophin (CG). These results underscore fundamental differences between human and mouse ES cells, which differentiate poorly, if at all, to trophoblast. Human ES cells thus provide a tool for studying the differentiation and function of early human trophoblast and could provide a new understanding of some of the earliest differentiation events of human postimplantation development. Groups of assays that are related as part of a time series. Keywords: time_series_design
Project description:Various chemicals, including pesticides, heavy metals, and metabolites of tobacco, have been detected in fetal environment. Fetuses are exposed to these chemicals at relatively low concentrations; however, their risk of developing neurological and behavioral disorders increases after birth. We aimed to evaluate the effects of five chemicals (diethylphosphate, cotinine, octachlorodipropyl ether, mercury, and selenium) detected in the serum of pregnant mothers on DNA methylation status during neural development using human neural stem cells.
Project description:With thousands of chemicals in commerce and the environment, rapid identification of potential hazards is a critical need. Combining broad molecular profiling with targeted in vitro assays, such as high-throughput transcriptomics (HTTr) and receptor screening assays, could improve identification of chemicals that perturb key molecular targets associated with adverse outcomes. We aimed to link transcriptomic readouts to individual molecular targets and integrate transcriptomic predictions with orthogonal receptor-level assays in a proof-of-concept framework for chemical hazard prioritization. Transcriptomic profiles generated via TempO-Seq in U-2 OS and HepaRG cell lines were used to develop signatures comprised of genes uniquely responsive to reference chemicals for distinct molecular targets. These signatures were applied to 75 reference and 1,126 non-reference chemicals screened via HTTr in both cell lines. Selective bioactivity towards each signature was determined by comparing potency estimates against the bulk of transcriptomic bioactivity for each chemical. Chemicals predicted by transcriptomics were confirmed for target bioactivity and selectivity using available orthogonal assay data from US EPA’s ToxCast program. A subset of 37 selectively acting chemicals from HTTr that did not have sufficient orthogonal data were prospectively tested using one of five receptor-level assays. Of the 1,126 non-reference chemicals screened, 201 demonstrated selective bioactivity in at least one transcriptomic signature, and 57 were confirmed as selective nuclear receptor agonists. Chemicals bioactive for each signature were significantly associated with orthogonal assay bioactivity, and signature-based points-of-departure were equally or more sensitive than biological pathway altering concentrations in 81.2% of signature-prioritized chemicals. Prospective profiling found that 18 of 37 (49%) chemicals without prior orthogonal assay data were bioactive against the predicted receptor. Our work demonstrates that integrating transcriptomics with targeted orthogonal assays in a tiered framework can support Next Generation Risk Assessment by informing putative molecular targets and prioritizing chemicals for further testing. NOTE: this GEO entry only includes the HepaRG cell line data; the U-2 OS cell line data can be located via GEO accession number GSE274318.