Advanced developmental toxicity test method based on embryoid body's area.

Area of Science:

• Developmental toxicology
• Stem cell biology
• Chemical risk assessment

Background:

• The Embryonic Stem Cell Test (EST) assesses embryotoxic potential using mouse embryonic stem cells (ESCs) and fibroblasts.
• Current EST methods focus on cell viability and cardiac differentiation inhibition.
• A need exists for more efficient and accurate developmental toxicity testing methods.

Purpose of the Study:

• To introduce and validate a novel developmental toxicity test (EBT) using embryoid body (EB) area as a key metric.
• To compare the efficacy of EBT with existing EST methods.
• To elucidate the molecular mechanisms underlying EBT-observed toxicity.

Main Methods:

• The EBT method was developed, utilizing EB area measurement instead of cardiac differentiation.
• Twenty-one chemical substances were assessed using the EBT.
• Next-generation sequencing was employed to investigate molecular changes associated with reduced EB area.

Main Results:

• EB area demonstrated a dose-dependent, logarithmic decrease upon exposure to tested substances.
• A decline in EB area correlated with a reduced beating ratio during ESC differentiation.
• The EBT-based prediction model achieved 90.5% accuracy in classifying the toxicity of 21 chemicals.
• Next-generation sequencing revealed cell cycle arrest mediated by HDAC2 and CDKN2A as a mechanism for EB area reduction.

Conclusions:

• The Embryoid Body Test (EBT) is an advanced and effective tool for assessing and classifying embryotoxicants.
• EBT provides a rapid and less labor-intensive alternative to traditional EST methods.
• The test accurately predicts developmental toxicity by integrating cell viability and EB area data, with insights into underlying molecular mechanisms.