Evaluation of developmental toxicity using undifferentiated human embryonic stem cells.

Area of Science:

• Developmental toxicology
• Stem cell biology
• In vitro toxicology

Background:

• Embryonic stem cell tests (ESTs) evaluate chemical embryotoxicity in vitro.
• Human embryonic stem (hES) cells offer a novel system for screening developmental toxicants.

Purpose of the Study:

• To evaluate novel methods for screening toxic chemicals during embryonic development using undifferentiated hES cells.
• To assess the impact of embryotoxic and non-embryotoxic chemicals on hES cell markers and gene expression.

Main Methods:

• Confirmed undifferentiated hES cell status using surface marker immunocytochemistry (SSEA-4, TRA-1-60, TRA-1-81).
• Treated hES cells with embryotoxic (5-fluorouracil, indomethacin) and non-embryotoxic (penicillin G) chemicals.
• Assessed changes in pluripotent ES cell markers (OCT-4, NANOG, etc.) and gene expression profiles (Affymetrix GeneChips).

Main Results:

• Embryotoxic chemicals down-regulated pluripotent hES cell markers in a dose-dependent manner.
• Gene expression profiling revealed convergence in up-regulation of development, cell cycle, and apoptosis-related genes after chemical exposure.
• Surface marker expressions were not significantly affected by the tested chemicals.

Conclusions:

• Embryotoxic chemicals exert cytotoxic effects and modulate key gene expressions in undifferentiated hES cells.
• hES cells are a promising tool for evaluating chemical toxicity during embryonic development.
• This study highlights the utility of hES cells in developmental toxicology screening.