Cell-Type-Specific Proteomic Profiling of Synaptosomes During Early and Extended Withdrawal from Self-Administered Cocaine

Addiction is a complex disorder that is exceptionally difficult to treat due to the high propensity for relapse even after a prolonged period of abstinence. The persistence of addiction is thought to be mediated by stable drug-induced changes in the physiology of reward-processing regions of the brain. Altered signaling within the nucleus accumbens (NAc) in particular appears to play a critical role in promoting drug-seeking and relapse. Determining these changes may reveal more effective targets to treat drug addiction and relapse. However, understanding the molecular details underlying these adaptations remains incomplete, especially in the context of cell-type and circuit specificity. Here, we propose expanding upon our previous work with the Yale/NIDA Neuroproteomics Center to examine drug-induced long-term, cell-type-specific synaptic changes within the NAc. Using wildtype, Drd1 x MT-MG, and Drd2 x MT-MG mice, we propose to profile cell-type-specific proteome changes induced by cocaine self-administration at two key time points: early (24 hours) and extended (30 days) withdrawal. After 10 days of intravenous cocaine or saline self-administration followed by 24 hours or 30 days of forced abstinence and cue-induced reinstatement test, mice will be euthanized, and the NAc will be extracted. Then, NAc synaptosomes will be purified, isolated by fluorescence-activated cell sorting (FACS), and analyzed by liquid chromatography tandem (LC-MS/MS) mass spectrometry followed by label-free quantification (LFQ) in collaboration with the Yale/NIDA Neuroproteomics Center. We anticipate characterizing alternations of synaptic proteins in a cell-type-specific manner — never before achieved — and expect to make important advances in our understanding of the molecular basis of cocaine addiction and relapse.