An Imaging-Based Human Embryonic Stem Cell Assay for Teratogenic Activity
In this work a human pluripotent stem cell (hPSC) assay was proposed as a novel imaging-based screen for identifying substances (teratogens) likely to cause birth defects in humans. The assay was engineered to leverage lessons from the validated mouse Embryonic Stem Cell Test (EST). An automated fluid handler was repurposed to support printing stem cells and biological materials to an innovative two-part microculture platform, the pillar/well chip system. Key milestones were met, demonstrating the applicability of the microculture platform to hPSC cultures over the duration of the proposed assay. Three proof-of-principle experimental data sets were acquired using statistical experimental design to eliminate confounding systematic variation and uncontrolled variables. Changes in cell population and expression of four protein biomarkers were observed with automated fluorescence microscopy and quantified by image analysis. Toxic molecules were found to show similar inhibition of viability to literature values. Further work is needed to optimize quantification and reduce variability in these signals to assess the effects of candidate teratogens on cell differentiation.