Prenatal ethanol exposure programs the fetal hypothalamic-pituitary-adrenal (HPA) axis such that HPA tone is increased throughout life, resulting in HPA hyperresponsiveness to stressors. The developmental programming concept states that early environmental stimuli can program metabolic and physiologic processes and as such increase vulnerability to illnesses or disorders later in life. Thus a long-term increase in HPA function will increase exposure to glucocorticoids over the lifespan and have adverse consequences for health. The mechanism(s) underlying such programming are unknown, but probably involve an interaction between environmental stimuli and epigenetic regulation of gene expression, such as changes in DNA methylation and/or chromatin structure (e.g. histone methylation, acetylation). An organism is especially vulnerable to epigenetic changes during development and the epigenome is highly susceptible to environmental stimuli such as maternal diet (including drugs and other toxic agents) and maternal behavior. We propose that in utero ethanol exposure is an environmental stimulus that elicits epigenetic changes with long-term adverse consequences. Because of the metabolic link of ethanol to methyl group metabolism we speculate that the HPA programming observed in adult animals exposed in utero to ethanol is a consequence of alterations in methyl group metabolism, gene-specific changes in DNA methylation patterns and a gene expression profile that promotes hyperresponsiveness to stress. Utilizing our well established model of prenatal ethanol exposure, we will test the hypothesis that prenatal ethanol exposure alters the methionine cycle and programs the fetal HPA axis through gene-specific changes in DNA methylation patterns and expression of the genes crucial to normal HPA activity and regulation.
Our Specific Aims are to determine if fetal ethanol exposure results in: 1) altered methyl status in offspring; and 2) changes in DNA methylation patterns and the expression profile in brain of the glucocorticoid receptor (Nr3c1) and the mineralocorticoid receptor (Nr3c2) genes. The proposed studies will begin to elucidate possible mechanisms underlying HPA programming and altered behavioral responses to stress in animals exposed to ethanol in utero. Our goal is to provide a framework for the future development of interventions that could be effective in rescuing these systems. ? ? ?
| Ngai, Ying Fai; Sulistyoningrum, Dian C; O'Neill, Ryan et al. (2015) Prenatal alcohol exposure alters methyl metabolism and programs serotonin transporter and glucocorticoid receptor expression in brain. Am J Physiol Regul Integr Comp Physiol 309:R613-22 |
| Kobor, Michael S; Weinberg, Joanne (2011) Focus on: epigenetics and fetal alcohol spectrum disorders. Alcohol Res Health 34:29-37 |
| Weinberg, J; Sliwowska, J H; Lan, N et al. (2008) Prenatal alcohol exposure: foetal programming, the hypothalamic-pituitary-adrenal axis and sex differences in outcome. J Neuroendocrinol 20:470-88 |
