The heat shock response: potential to screen teratogens

Area of Science:

• Developmental Biology
• Toxicology
• Molecular Biology

Background:

• The embryonic stress hypothesis posits that congenital defects result from failed gene transcription, preempted by the heat shock response (HSR).
• The HSR is a cellular defense mechanism involving the synthesis of heat shock proteins (HSPs).
• Investigating the HSR's role in teratogenesis is crucial for understanding congenital defect origins.

Purpose of the Study:

• To evaluate the utility of the murine heat shock response (HSR) as a screening tool for potential human teratogens.
• To assess the correlation between HSR induction and teratogenic effects of specific agents in mice.

Main Methods:

• Pregnant SWV mice were administered known teratogenic and non-teratogenic agents during critical neural tube closure periods.
• Heat shock protein (hsp) synthesis and total protein synthesis were measured in splenic lymphocytes post-exposure.
• Dose selection considered teratogenic levels or maximum non-maternally toxic doses for non-teratogens.

Main Results:

• Exposure to teratogenic agents (hyperthermia, retinoic acid, valproic acid, insulin) induced varied heat shock protein (hsp) synthesis.
• Non-teratogenic agents (cycloheximide, dinitrophenol, tetracycline) also elicited inconsistent hsp responses.
• Changes in total protein synthesis were observed but did not consistently correlate with teratogenic potential.

Conclusions:

• The murine heat shock response (HSR) demonstrated inconsistent induction patterns across tested agents.
• Varied results suggest the HSR is not a reliable indicator for screening potential human teratogens.
• Further research is needed to identify robust biomarkers for teratogenicity screening.