Neuropeptidergic regulation of valence processing underlying the sex differences in AUD

PROJECT SUMMARY Alcohol use disorder (AUD) is one of the most prevalent mental disorders worldwide. Compared to men, women not only suffer from greater alcohol intoxication and withdrawal effects but also develop AUD more rapidly. It suggests that women may be particularly susceptible to the negative valence induced by alcohol withdrawal, which leads to escalated alcohol drinking. However, how valence processing is differentially affected by chronic alcohol drinking between males and females and contributes to the sex differences in the development of AUD is still unknown. A key brain region implicated in valence processing that is dysregulated by alcohol is the bed nucleus of stria terminalis (BNST). Studies show that the BNST exhibits significant sexual dimorphism and is essential for encoding the positive and negative properties of alcohol. In addition, BNST neural activity can be modulated by neuromodulatory actions of neurotensin (NT), a 13 amino acids neuropeptide differentially regulated by sex hormones. Studies have shown that NT enhances inhibitory inputs to BNST neurons and mediates anxiety-like behavior via postsynaptic NT receptor type 1 (NTSR1) and that NT gene expression is correlated with alcohol consumption in women. Together, these findings suggest a sex- dependent NTergic modulation of the BNST on negative affect states during alcohol drinking. We will test the central hypothesis that NTergic modulation mediates the sex difference in alcohol drinking by selectively enhancing BNST encoding of negative valence during acute withdrawal via NTSR1. Aim 1: We will test whether acute alcohol withdrawal enhances BNST encoding of negative valence in females via NTSR1. We will record BNST glutamatergic and GABAergic neurons using in vivo electrophysiology and optogenetic photo tagging in a valence discrimination task before and weekly during the withdrawal periods of intermittent access (IA) alcohol drinking paradigm in both sexes of mice with and without Cre-dependent CRISPR-Cas9 knockdown of Ntsr1 in the BNST. Aim 2: We will examine whether NTSR1 signaling in the BNST drives the escalated alcohol drinking in females by pharmacologically or genetically inhibiting BNST NTSR1 at different stages of the IA paradigm or in glutamatergic and GABAergic neurons of both sexes. Aim 3: We will dissect the NT sources that regulate BNST NT dynamics during valence processing and alcohol drinking. We will measure BNST NT dynamics to motivational valence during a valence discrimination task before and weekly during IA alcohol drinking in both sexes with and without optogenetic inhibition of NTergic inputs to the BNST. We will also examine whether Nts CRISPR knockdown in these projections before IA alcohol drinking affects alcohol drinking of both sexes. Successful completion of this proposal will reveal the functional architecture of NT in mediating dysregulated valence processing in the BNST by IA alcohol drinking and provide critical knowledge of neuropeptidergic modulations in sex differences in AUD.