Variation of Myelin-associated Gene Expression and Ndrg1 within the Prefrontal Cortex as Determinants for Initial Level of Response to Alcohol.

BACKGROUND

Studies in humans and animal models have documented relationships between initial sensitivity to alcohol and alcohol drinking behavior.Prior expression profiling studies of C57BL/6J and DBA/2J mice and rhesus macaques within the prefrontal cortex (PFC) have shown variation in myelin gene expression may be linked with alcohol sensitivity and consumption.

METHODS

Combining gene expression studies from human and mouse PFC, we identified a cross-species gene network enriched for myelin-associated genes. Since myelin expression is correlated to alcohol sensitivity and alcohol drinking behavior, we hypothesized basal levels of PFC myelin gene expression may be a genomic determinant for these behavioral responses. Using an animal model of CNS demyelination, and localized knock down of N-myc downstream regulated gene 1 (Ndrg1), we measured effects of cortical myelin reduction on initial alcohol sensitivity and drinking behavior.

RESULTS

Reducing myelin-related gene expression significantly altered sensitivity to alcohol and decreased alcohol consumption. Mouse genetic-based studies identified Ndrg1 as a putative quantitative trait gene for sedative-hypnotic responses to alcohol. Site-specific injections of shNdrg1 lentivirus into PFC led to a significant decrease in NDRG1 expression, causing increased alcohol behavioral sensitivity and reduced preference for high concentrations of alcohol.

CONCLUSION

Myelin is an important biological component underlying CNS disorders. Our studies demonstrate the role of a novel candidate gene (Ndrg1), and myelin-associated gene expression, as an important factor modulating initial sensitivity to alcohol and alcohol consumption. Differences in the expression of myelin-related genes, including Ndrg1, may serve as future therapeutic targets for the treatment of alcohol use disorders.