Long-lived epigenetic interactions between perinatal PBDE exposure and Mecp2308 mutation

Area of Science:

• Environmental Toxicology
• Neuroepigenetics
• Developmental Neuroscience

Background:

• Persistent organic polybrominated diphenyl ethers (PBDEs) are flame retardants with potential long-term human health effects.
• Epigenetic mechanisms like DNA methylation are sensitive to environmental factors and influence neurodevelopment.
• Autism spectrum disorders (ASDs) involve complex genetic and environmental interactions, with Rett syndrome linked to MECP2 mutations.

Purpose of the Study:

• To investigate the long-lasting effects of perinatal 2,2',4,4'-tetrabromodiphenyl ether 47 (BDE-47) exposure.
• To examine these effects in a mouse model with a mutation in the epigenetic factor methyl-CpG binding protein 2 (MECP2).
• To assess developmental, behavioral, and epigenetic outcomes, considering sex and genotype.

Main Methods:

• Perinatal exposure of Mecp2(308/+) dams to BDE-47.
• Breeding exposed dams to wild-type males to obtain offspring of various sexes and genotypes.
• Evaluation of fertility, preweaning weights, sociability, short-term social novelty memory, and spatial learning/memory (Morris water maze).
• Analysis of global DNA methylation and specific gene expression (Dnmt3a).

Main Results:

• BDE-47 exposure reduced fertility in dams and preweaning weights in female offspring.
• Global DNA hypomethylation in adult female offspring brains exposed to BDE-47 correlated with reduced sociability.
• A genotype-dependent interaction was observed in social novelty memory, with increased Dnmt3a in exposed Mecp2(308/+) offspring.
• Impaired learning and long-term memory in the Morris water maze were noted in female Mecp2(308/+) offspring exposed to BDE-47.

Conclusions:

• Perinatal BDE-47 exposure induces long-lasting behavioral and epigenetic changes in a susceptible mouse model.
• These effects exhibit sexual dimorphism and result from gene-environment interactions.
• The study reveals epigenetic dysregulation, compensatory mechanisms, and specific deficits relevant to social and cognitive behaviors.