Bringing Cutting-Edge Molecular Methods to Nonhuman Primate Studies of Pathological Anxiety
A critical step to establishing new treatments for psychiatric illness lies in defining the underlying molecular alterations that determine why some children are vulnerable to developing these disorders. To identify these molecular differences, our laboratory uses the tools of pharmacology, biochemistry and molecular biology in conjunction with our nonhuman primate model. We utilize technologies such as RNA sequencing (RNA-Seq, including single cell RNA-Seq), often used in conjunction with laser capture microdissection, to discover novel, functionally-significant candidate genes that have brain mRNA levels that correlate with the expression of AT across subjects. To test candidate genes, we can then use non-replicating viral vectors (e.g., adeno-associated virus (AAV) and lentivirus) that infect cells within key AT-related brain regions to direct an increase or decrease in the expression of these same candidate genes to further understand their role in the expression of AT. Using chemogenetic strategies, such as designer receptors exclusively activated by designer drugs (DREADDs) and pharmacologically selective actuator modules (PSAMs), we are refining our understanding of the AT neural circuit by reversibly altering the activity of neurons within targeted brain regions. This technology allows for fine-tuning the function of circuits critically involved in mediating pathological anxiety. Additionally, to understand the role of genetics and epigenetics in psychiatric disease susceptibility, we are using a large cohort of ~600 monkeys that belong to a multigenerational pedigree, to screen for DNA polymorphisms and DNA methylation differences. Lastly, we are investigating the molecular underpinnings of the mechanism of action of the rapidly acting antidepressant ketamine and its metabolites in our nonhuman primate model. Ultimately, discoveries arising from this work will identify critical molecules and pathways that can serve as targets for the development of the next generation of psychiatric treatments. This includes the exploration of direct neural-circuit modulation using chemogenetic strategies.