The overall goal of this project is to improve our understanding of the acute effects of alcohol on G-protein coupled receptor (GPCR) signaling. Acute alcohol use produces profound changes in the signaling of many GPCRs in the brain, which coincide with diverse neurological responses to alcohol, including memory impairment, reward and loss of coordination. Because these molecular responses to alcohol are a key predictor of vulnerability to alcohol use disorders, it is crucial to better understand how GPCR signaling is modulated in response to alcohol. One potential regulator of ethanol-induced alterations in GPCR signaling is membrane cholesterol because acute alcohol exposure alters membrane cholesterol homeostasis. In both rat prefrontal cortex (PFC) and neuroblastoma N2A cells stably expressing 5-HT1A receptors (5-HT1ARs), I found that ethanol increased both membrane cholesterol content and 5-HT1AR-mediated G-protein signaling. In parallel, I found that ethanol treatment increased partitioning of 5-HT1AR/G-protein into lipid rafts of N2A cells, suggesting that cholesterol regulates receptor/G-protein translocation into lipid rafts. In this NRSA proposal, I will test the central hypothesis that membrane cholesterol regulates ethanol-induced increase in 5-HT1AR- mediated G-protein signaling by facilitating compartmentalization of 5-HT1AR, G?i3 and adenylyl cyclase (AC) into lipid rafts. I will test this hypothesis through two Specific Aims.
In Aim 1, I will use simvastatin, an inhibitor of HMG-CoA reductase involved in cholesterol synthesis, to deplete brain cholesterol and measure 5-HT1AR- mediated G-protein signaling in rat PFC after acute ethanol exposure.
In Aim 2, I will employ a N2A cell model to determine the effect of cholesterol depletion on compartmentalization of 5-HT1AR, Gai3 and AC in lipid rafts after acute ethanol exposure. Collectively, these studies will highlight membrane cholesterol as an important factor contributing to alcohol abuse through its regulation of alcohol-induced alterations in GPCR compartmentalization and signaling and identify cholesterol as a potential target for more effective treatment of alcohol use disorders.

Public Health Relevance

Alcohol abuse is an epidemic, yet our understanding of its targets and molecular mechanisms remain elusive. This project will implicate brain cholesterol as an important modulator of alcohol mediated neuroadaptations and provide a rationale for targeting brain cholesterol as a new avenue for treatment of alcohol abuse.

Agency
National Institute of Health (NIH)
Institute
National Institute on Alcohol Abuse and Alcoholism (NIAAA)
Type
Predoctoral Individual National Research Service Award (F31)
Project #
5F31AA025532-02
Application #
9669893
Study Section
Special Emphasis Panel (ZAA1)
Program Officer
Liu, Qi-Ying
Project Start
2018-03-11
Project End
2020-03-10
Budget Start
2019-03-11
Budget End
2020-03-10
Support Year
2
Fiscal Year
2019
Total Cost
Indirect Cost
Name
Wake Forest University Health Sciences
Department
Physiology
Type
Schools of Medicine
DUNS #
937727907
City
Winston-Salem
State
NC
Country
United States
Zip Code
27157