Reproductive Toxicology

Trichloroethylene Exposure in Mid-Pregnancy Decreased Fetal Weight and Increased Placental Markers of Oxidative Stress in Rats Tables list data supporting Figures. Table S1. Data used to generate Figure 1: Fetal growth restriction with no effect on maternal weight and litter size Table S2. Data used to generate Figure 2: Placental DNA modification by TCE Table S3. Data used to generate Figure 3: TCE effect on ten-eleven translocation (Tet) (mRNA fold change relative to control) Table S4. Data used to generate Figure 4A: glutathione S-transferase (GST) activity in the placenta (nmol/min/mg protein)

In zebrafish, 161 compounds were screened and 34 were identified by visual inspection as VDCs, of which 28 were confirmed as VDCs by quantitative image analysis. Testing of the zebrafish VDCs for their capacity to inhibit endothelial tube formation in the murine yolk-sac-derived endothelial cell line C166 identified 22 compounds that both disrupted zebrafish vascular development and murine endothelial in vitro tubulogenesis.

ToxRefDB comprises information from over fifty years of in vivo toxicity data. The database includes information for over 1000 chemicals, and is being used as a primary source of data for evaluating efforts of the ToxCast program [4,5], as well as for numerous predictive and retrospective analyses.

Aspirin modifies O3 effects

This study evaluated two anti-angiogenic agents, 5HPP-33 and TNP-470, across the ToxCastDB HTS assay platform and anchored the results to complex in vitro functional assays: the rat aortic explant assay (AEA), rat whole embryo culture (WEC), and the zebrafish embryotoxicity (ZET) assay.

Development of the neurovascular unit (NVU) is a complex, multistage process that requires orchestrated cell signaling mechanisms across several cell types and ultimately results in the formation of the blood-brain barrier. Typical high-throughput screening (HTS) assays investigate single biochemical or single cell responses following chemical insult. As the NVU comprises multiple cell types interacting at various stages of development, a methodology for combining high-throughput results across pertinent cell-based assays is needed to investigate potential chemical-induced disruption to the development of this complex cell system. To this end, we developed a novel method for screening putative NVU disruptors across diverse assay platforms to predict chemical perturbation of the developing NVU. Here, HTS assay results measuring chemical-induced perturbations to cellular key events across angiogenic and neurogenic outcomes were combined to create a cell-based prioritization of NVU hazard. Using activity from each biological outcome, chemicals were grouped into similar modes of action and used to train a logistic regression literature model. This model utilizes the chemical-specific pairwise mutual information score for PubMed MeSH annotations to represent how often a chemical was shown to produce a specific outcome in the published literature space. Taken together, this study presents a methodology to investigate NVU developmental hazard using cell-based HTS assays and literature evidence to prioritize screening of putative NVU disruptors. The results from these screening efforts demonstrate how chemicals that represent a range of putative vascular disrupting compound (pVDC) scores based on angiogenic endpoints can also produce effects on neurogenic outcomes such as neurite outgrowth, neuroprogenitor/neural crest migration, representing an additional method for understanding the range of possible modes of action for disruption of the developing NVU.

We differentiated human induced pluripotent stem cells (hiPSCs) to embryonic endoderm and sought to identify a tipping point at which the developing system did not recover from perturbations caused by exposure to a known teratogen, all-trans retinoic acid (ATRA). Differentiating iPSC-derived endoderm was exposed to five concentrations of ATRA between 0.001 and 10 µM at 6h, 96h, or 192h and assessed for forkhead box A2 (FOXA2) protein expression and global gene transcript expression measured by RNA-sequencing. A tipping point of 17±11 nM was identified where patterns of differentially expressed genes supported a shift in the developmental trajectory away from embryonic endoderm in favor of mesoderm and extraembryonic endoderm. Five concentrations of all-trans retinoic acid (ATRA) between 0.001 and 10 µM were compared to time-matched 0.1% DMSO controls at three timepoints (6h, 96h, and 192h) in differentiating endoderm. Two biological replicates were used. Undifferentiated controls (not in DMSO) were also included in duplicate as internal controls for 6h, 96h, and 144h.

The systems map described in this manuscript for neurulation will set the stage for constructing mathematical models and computer simulation of neural tube closure for human-relevant AOPs and predictive toxicology of neural tube defects such as spina bifida.