Neuronal subtype and circuit-specific epigenetic mechanisms in addiction

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 DESCRIPTION (provided by applicant): This proposal requests support for a comprehensive training plan that will enable the candidate, Dr. Gregory C. Sartor, to expand, develop, and refine technical skills that are necessary for a productive independent research career. The goal of the training plan is to acquire advanced molecular biology techniques through supervised hands-on training and didactic coursework in order to incorporate sophisticated methods into Specific Aims focused on elucidating cell type- and circuit-specific epigenetic mechanisms in addiction. The advanced scientific training will be focused on two key areas: 1) Fluorescence-activated cell sorting (FACS) of neuronal subtypes from addiction-related brain regions, and 2) developing viral-mediated gene transfer tools to manipulate epigenetic targets in a cell type- and connection-specific fashion. The career development activities will be mentored by Dr. Claes Wahlestedt with collaborative support from Drs. Kasahara and Gray, all of which have non-overlapping expertise in the methods proposed and have exceptional records of mentoring postdoctoral trainees. The research component will investigate acetyl lysine reader proteins, termed BET bromodomains, an emerging, drugable epigenetic target that is currently being studied in multiple clinical trials. These bromodomain-containing proteins bind acetylated histones and serve as a scaffold for the recruitment of macromolecular complexes that modify chromatin accessibility and transcriptional activity. I recently found that BET proteins are upregulated and recruited to the promoter region of Bdnf in the nucleus accumbens (NAc) following chronic cocaine administration. Furthermore, my data show that pharmacological inhibition of these BET proteins (systemic and intra-NAc) attenuates behavioral responses to cocaine. However, recent evidence indicates that cocaine-induced behaviors and associated chromatin modifications are regulated in a cell type-specific manner in the NAc. Therefore, precise examinations of BET proteins within this anatomically and functionally heterogeneous region are critically needed to fully understand the role of these proteins in complex addiction behaviors. My overall hypothesis is that modulation of epigenetic reader proteins in a cell type- and projection-dependent manner will attenuate cocaine seeking behaviors. Aim 1 will require training in FACS in order to determine the cell-type specific time course of BET mRNA/protein expression following short and long access to cocaine self-administration. Aim 2 will require proficiency in viral-mediated gene transfer techniques in order to manipulate BET proteins in specific cell types within the NAc during cocaine seeking behaviors. The R00 independent phase builds on this training to focus more specifically on connection-specific changes and manipulations of BET proteins during cocaine seeking behaviors. Together, these innovative studies will be the first to systemically explore epigenetic targets in cell type- and connection- specific manner during complex behaviors.