Measuring the impact of prenatal alcohol exposure on the fetal epigenome

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DESCRIPTION (provided by applicant): Prenatal exposure to alcohol severely affects growth and differentiation of the fetus and causes a wide range of developmental abnormalities. These vary in severity, from barely detectable to crippling physical and cognitive disabilities that are collectively referred to as fetal alcohol spectrum disorders (FASDs). Correlation of alcohol sensitive developmental windows with major periods of DNA methylation and histone remodeling suggest an underlying epigenetic mechanism to the bewildering heterogeneity in FASD phenotype. Heritable, long lasting changes to the DNA methylation and post-translational histone modification profile of the embryo alter the developmental program of the fetus, and have the potential to result in severe developmental abnormalities. Despite the wealth of observational data confirming the capacity of prenatal alcohol exposure to negatively affect the embryonic epigenome, there is a paucity of information explaining the underlying mechanism. The best models for investigating epigenetic programming are genomic imprinting, X-inactivation and retrotransposon silencing. As the first two processes are specialized transcriptional regulatory mechanisms, study of the latter offers opportunities for insight into general epigenetic gene regulation and how it is influenced by prenatal alcohol exposure. The long-term goal of this project is to develop and validate an in vivo model to monitor epigenetic programming and examine tissue specific changes to the fetal epigenome in response to alcohol exposure. The hypothesis to be tested in this proposal is that prenatal exposure to alcohol during different developmental windows induce tissue specific alterations in the fetal epigenome which can be correlated with the diverse phenotypes of FASDs. The innovative aspect of this proposal is the development of a Green Fluorescent Protein (GFP) containing retro-element reporter based on the agouti-IAP element. Tissues exposed to ethanol will loose repression of the IAPGFP reporter leading retro-element activation and GFP expression. As a result, affected organs and tissues will turn green. We hypothesize that tissues known to be sensitive to alcohol exposure during specific developmental windows will change color according to dosage and timing of ethanol exposure. In validation of our model we will correlate GFP expression with known changes in tissue specific gene expression and established epigenetic modifications of both the IAPGFP reporter and candidate genes. In summary, this reporter will enable in-depth analysis of the epigenetic influence of ethanol during development while at the same time providing a platform to examine the efficacy of therapeutic interventions. Given the critical role of epigenetics in maintaining stem cell identity and differentiation, understanding how, when and what dose of alcohol exposure is sufficient to alter the developmental program of the fetus is crucial step in our goal to better understand the epigenetic basis of FASDs. PUBLIC HEALTH RELEVANCE: Early pregnancy is a critical window in child development. This proposal will examine basic fundamental mechanisms by which exposure to alcohol in the womb can result in recurrent pregnancy loss and development of childhood diseases. Understanding how mental and physical disabilities associated with drinking during pregnancy arise is critical for developing preventative measures and treatments.