Investigation of the Molecular Mechanisms Underlying Astrocytic CREB's Regulation of Cocaine Drug-Seeking

PROJECT SUMMARY Drug addiction represents an enormous healthcare burden. To better understand its biological underpinnings, investigations of the transcriptional response to drugs of abuse have demonstrated lasting changes in gene expression throughout the brain’s reward circuitry. Historically focused on neurons, emerging evidence increasingly indicates that astrocytes are also involved in disorders of the nervous system, including addiction. Indeed, candidate genes in astrocytes have been identified and, furthermore, manipulation of astrocyte function has been demonstrated to influence rodent behavioral responses to cocaine administration. However, the astrocyte-specific transcriptome and its regulation following exposure to drugs of abuse has not yet been investigated. In my career, I will build an independent research program that investigates the astrocyte transcriptome and its regulation in the context of addiction. This proposal will elucidate the underlying molecular mechanisms governing astrocytic CREB’s regulation of cocaine addiction-related behavior. Under the mentorship of Drs. Eric Nestler and Paul Kenny, I will rescue neuronal hypoactivity with DREADDs stimulation and record astrocyte calcium transients during cocaine SA. With additional mentorship from Dr. Li Shen, I will determine sex-specific astrocytic histone H3K27me3 gene targets and downstream molecular and cellular consequences to increase the rewarding properties of cocaine through bioinformatic comparison of CUT&RUN- and RNA-Sequencing. Viral-mediated manipulation to key H3K27me3 demethylase (Kdm6a/UTX) will uncover the contribution of astrocytic epigenetic regulation to cocaine drug-seeking. My independent laboratory will investigate the transcriptional and epigenetic regulation of astrocytes in the context of drug abuse and addiction. These experiments will prepare me to examine and manipulate cocaine-induced transcriptional and epigenetic modifications in astrocytes in my independent research laboratory. In sum, the research proposed in this Career Mentored Award will increase our understating of how regulation of the astrocyte transcriptome modulates behavioral responses to drugs of abuse. More broadly, the added training afforded by this award will prepare me to launch an independent research program that investigates the regulation of astrocyte gene expression, at both the transcriptional and epigenetic level, and distinguish its contributions to addiction phenotypes.