Designing synthetic transcription factors to study drug-specific transcription and behaviors

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PROJECT SUMMARY The nucleus accumbens (NAc) is a key brain region which encodes responses to both natural and drug reinforcers. All drugs of abuse are known to increase the dopaminergic tone in the NAc, making it a central brain structure in coordinating drug response. Drugs of abuse act largely through synaptic targets to alter intracellular signaling cascades which leads to the activation or inhibition of transcription factors, which in turn induce or repress the expression of specific genes. These drug-induced functions of brain transcription factors are sensitive to, and contribute to, the epigenetic landscape within a neuron and have been associated with lasting alterations in neuronal function and drug-related behaviors. Therefore, understanding the drug-induced function of transcription factors in this brain area may expand our understanding of how drugs of abuse can coordinate lasting changes in drug-related behaviors. This knowledge is critical for the development of the next generation of specific substance use disorder (SUD) medications. Here, I propose innovation centered on synthetic biology approaches to re-program the function of transcription factors, for viral delivery in the brain of awake and behaving mice, to resolve the exact, damaging transcription factor functions that are distinct to stimulant versus opioid addiction. I propose to accomplish this by applying novel synthetic transcription factor constructs combined with brain transcriptome profiling and drug self-administration procedures. This project focuses on ZFP189, a novel drug-activated transcription factor that I have carefully characterized in my earlier graduate work. First, in the NAc, I will virally deliver synthetic ZFP189 transcription factors, which possess artificial functional moieties capable of exerting distinct forms of transcriptional control at all in vivo target genes. I will perform RNA sequencing approaches to uncover how the complete gene-regulatory functions of a ZFP189 are differentially engaged in the context of stimulant versus opioid use. Second, I will utilize these same synthetic ZFP189 transcription factors to investigate their causal contributions to drug reinforcement using intravenous drug self-administration procedures. By innovating the application of synthetic transcription factors that can be programmed to exert novel forms of gene regulation across the genome, these techniques can be combined with existing RNA sequencing and complex behavioral procedures to serve as tools for both molecular interrogation into the transcription factor functions distinct to specific drugs of abuse and as highly specific transcription manipulations to uncover the causal gene regulatory events that drive certain SUDs. Together, this work will provide new approaches to identify the transcription factor functions at the core of specific SUDs and yield refined gene candidates as targets for future SUD medications.