Search

S31.1 ADOLESCENT INTERMITTENT ETHANOL-INDUCED HISTONE MODIFICATIONS AND DNA DEMETHYLATION: ROLE IN ANXIETY AND ALCOHOLISM {#article-title-2} Histone modifications and DNA methylation/demethylation regulate gene expression and play an important role in synaptic plasticity. We investigated the effects of adolescent intermittent ethanol (AIE) treatment on epigenetic modifications in the amygdala and on anxiety-like behaviors in adolescent and adult rats. The effects of AIE [2 g/kg, intraperitoneal; 2-days on/2-days off, 4 cycles (8 injections), postnatal days 28-41] on anxiety-like behaviors in adolescent rats was measured during withdrawal and effects of AIE exposure on anxiety-like and alcohol drinking behaviors at adulthood (postnatal day 92) were measured. Adolescent rats displayed anxiety-like behaviors after 24 hrs of ethanol withdrawal. At this time point, amygdaloid nuclear and cytosolic HDAC activity and levels of HDAC2 and HDAC4 were increased and histone (H3-K9) acetylation in the central (CeA) and medial amygdala (MeA) was decreased. Interestingly, in AIE adult rats nuclear HDAC activity and HDAC2 protein levels remained increased and histone acetylation remained decreased. We also found decreased histone H3 acetylation in promoters of Arc, NPY, and various BDNF exons in the amygdala of AIE compared with control (adolescent intermittent saline) adult rats. AIE produced a reduction in dendritic spines in the CeA and MeA and decreased mRNA levels of GADD45g, but not GADD45a or GADD45b in the amygdala of adult rats. AIE induced anxiety-like and alcohol drinking behaviors at adulthood were attenuated by treatment with trichostatin A. These results suggest that AIE induced epigenetic changes in the amygdala may play a crucial role in anxiety-like and alcohol-drinking behaviors at adulthood (supported by NADIA grant from NIH-NIAAA). # S31.2 IS THERE A FUTURE FOR USING HDAC INHIBITORS IN ALCOHOL DEPENDENCE? {#article-title-3} Emerging evidence suggests that epigenetic alterations to the genome, including DNA methylation and histone modifications, are important mechanisms underlying alcohol addiction. With the new field of epigenetics, there is now the opportunity to integrate the role of the epigenome not only in the short-term effects of alcohol but also in the enduring neuro-adaptations caused by chronic use of alcohol. The epigenetic modifications may be part of the neuro-adpatations occurring during the transition from the controlled intake to the loss of control and may explain how alcohol can have such a persistent effect on brain gene expression and functioning. There are now accumulating data showing that pharmacological tools targeting enzymes involved in epigenetic modifications may be useful in reducing or preventing some behavioral responses to alcohol. In the present work we have investigated the effects of different HDAC inhibitors (sodium butyrate, trichostatine A, MS-275 and sirtinol) on alcohol intake in rats with several paradigms, i.e. operant 10% ethanol self-administration, intermittent 20% ethanol intake and alcohol deprivation effect. We have also investigated the effects of HDAC inhibitors on excessive alcohol intake in alcohol-dependent animals and explored associated modifications in the brain levels of acetylated histone H3. Finally we tested the effects of HDAC inhibitors on ethanol-induced behavioral locomotor sensitization in mice and analyzed alterations in striatal gene expression and both HDAC and HAT activities. Altogether our results show that HDAC inhibitor can reduce and / or prevent several behavioral effects of alcohol and that this effect of HDAC inhibitors can be due, at least in part, to epigenetic mechanism. # S31.3 GENETIC AND ENVIRONMENTAL RISKS FOR PATTERNS OF ALCOHOL USE FROM ADOLESCENCE THROUGH EARLY ADULTHOOD {#article-title-4} Purpose. Early and heavy initiation of alcohol use is a risk for later abuse and health problems; hence, identifying contributors to youth alcohol use is a central goal. This paper seeks to delineate trajectories of alcohol use and abuse from early adolescence through early adulthood, and identify environmental and genetic risk factors contributing to problematic patterns of early alcohol use. We compare four leading explanations for problematic alcohol use: social norms, social controls, stress, and genetic predispositions. Methods. Data were drawn from a nationally representative study of American youth (Add Health), following 20,745 youth from early adolescence through early adulthood. Youth reported on alcohol use and inebriation. Youth, parents, peers, and school administrators reported on social norms (parent drinking, peer drinking, schoolmate drinking), social controls (parental supervision, monitoring, school punishment), and stressful life events. A genetic risk score was calculated using DNA data on three dopaminergic polymorphisms (DRD4, DAT1, MAOA). Results. Trajectory analysis found five patterns of alcohol use from early adolescence through early adulthood, delineating abstainers, low users, early declining, early increasing, and late increasing patterns of alcohol use. Analyses identified four trajectories of inebriation: abstainers, low users, early declining, and increasing. Multilevel multinomial logistic regression models predicted patterns of drinking and inebriation, finding significant effects of social norms, social control, and life stressors for males' patterns of alcohol use and inebriation. For females, social norms, life stressors, and genetic risks were significant predictors of alcohol use and inebriation. Models found little evidence of gene by environment interactions. # S31.4 PRENATAL ETHANOL-INDUCED HYPERMETHYLATION OF PROOPIOMELANOCORTIN GENE TRANSMITS THROUGH GERMLINE {#article-title-5} We have recently shown that alcohol exposure during the fetal period permanently suppresses the expression of stress controlling beta-endorphin due to hypermethylation of it's precursor POMC gene. In this study, we determined the mechanism by which the POMC gene is hypermethylated. Additionally, transgenerational studies were conducted to evaluate the germline-transmitted effect of alcohol. We found that fetal alcohol exposure decreased the levels of the activation histone marks H3K4, aceH3K9 and pH3S10 in POMC neurons, and increased the repressive histone mark H3K9. The fetal alcohol exposure also altered the protein levels and gene expression of POMC, Set7/9, CBP, HDAC2, G9a, Setdb1, MeCP2 and Dnmt1 except for Dnmt3a. Alcohol treatment also reduced the activation mark H3K4me3 along Exon 3 of POMC gene. Suppression of histone deacetylation and DNA methylation normalized POMC expression and functional abnormalities. Gestational choline supplementation also reversed alcohol-induced alteration in histone-modifying and DNA-methylating enzymes and normalized POMC gene promoter methylation, POMC gene expression and β-endorphin peptide production in POMC neurons. Fetal alcohol-induced POMC gene methylation, expression and functional defects persisted in the F2 and F3 male but not in female germline. Additionally, the hypermethylated POMC gene was detected in sperms of fetal alcohol exposed F1 offspring that was transmitted through F3 generation via male germline. Overall, these research findings collectively demonstrate that epigenetic changes contribute to the effects of fetal alcohol exposure on POMC gene expression as well as the perpetuation of abnormal POMC neuronal functions through subsequent generations via the male. (Supported by NIH Grant AA016695 and R37 AA08757).