Proteomic analysis of central amygdala systems regulated by the glucocorticoid receptor antagonist mifepristone in the context of alcohol dependence

Alcohol use disorder (AUD) is a chronic psychiatric disorder characterized by escalated alcohol use and emergence of negative emotional states during withdrawal. Studies show a dysregulation of glucocorticoid signaling in AUD, affecting the hypothalamic-pituitary-adrenal (HPA) axis and the central amygdala (CeA). Excessive activation of glucocorticoid receptors (GRs) is hypothesized to promote cognitive dysfunction, negative emotional states, and escalated drinking. Previous work demonstrates a functional increase in GR activity in the CeA during alcohol withdrawal in alcohol-dependent animal models. Importantly, the GR antagonist mifepristone reduces alcohol-seeking and drinking behaviors in rodents and humans. The aims of this study were to determine differential CeA protein expression in alcohol-dependent rats and examine the effects of mifepristone treatment. We hypothesized that male and female rats will show sex differences in their CeA protein expression and that alcohol-induced reductions in brain anti-stress signaling (e.g., endocannabinoid system) will be normalized by mifepristone treatment. Male and female Wistar rats were exposed to chronic intermittent ethanol vapor (CIEV) or air (control) for 10 weeks. In week 7, half of each group received subcutaneous placebo pellets while the other half received mifepristone pellets (150mg, 21-day slow release). At the end of Week 10, the rats were sacrificed during acute (6-hour) CIEV withdrawal (and identical time in control groups). The CeA was analyzed using proteomics and ingenuity pathway analysis (IPA). In males, a total of 3050 proteins were detected in the CeA. Of these, 142 proteins were altered by alcohol (but not mifepristone), whereas an additional 253 proteins were altered by alcohol and “normalized” by mifepristone. In females, among the 2632 detected proteins, 46 were affected by alcohol (but not mifepristone), and 25 were altered by alcohol and restored by mifepristone. IPA revealed significant changes in canonical pathways, including the endocannabinoid neuronal synapse pathway and oxidative phosphorylation, affected by alcohol but normalized by mifepristone. Future studies will incorporate alcohol self-administration procedures in male and female rats to functionally examine proteins within these pathways as promising “druggable” targets that offer novel therapeutic avenues for AUD. Supported by NIH-NIAAA R01AA025996, P60AA009803, T32AA007577. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.