Vanessa B. Sanchez

Vanessa B. Sanchez, a psychology major at California State University, Fullerton, characterized a series of enhancers in the context of rAAVs specific towards subtypes of GABAergic interneurons.

Understanding how cortical networks function begins at the excitatory–inhibitory balance controlled by interneurons. The Broad Institute’s enriched intellectual environment and collaborative nature immersed me in cutting-edge research in a variety of fields. The supportive structure here allowed me to fully dive into my research project and confirmed my research interests. Everyone encourages you to cultivate your passion. I was able to build long lasting relationships, learn new lab techniques, and think and speak like a scientist.GABAergic interneurons are inhibitory neurons that comprise 20% of the neurons in the cortex. Alteration of their function has been associated with a wide variety of neuropsychiatric disorders such as autism, schizophrenia and bipolar disorders. Until recently, the tools to target and manipulate inhibitory interneurons was limited to the use in transgenic mice. Our laboratory recently developed a strategy that efficiently addresses this limitation by combining the recombinant adeno-associated virus (rAAV) with the regulatory power of a short enhancer sequence. This novel strategy has been shown to restrict gene expression to GABAergic interneurons across species, thus opening the possibility to study interneuron function in primates including humans.

Interneurons are remarkably variable, and each subtype plays a functionally distinct role. With this in mind, we’ve identified a series of putative enhancers for selective expression of AAVs within specific interneuron subtypes. We developed a robust screening method that combines RNAscope in situ hybridization and immunostaining. Using this approach, we assessed the specificity of expression conferred by candidate sequences specific to parvalbumin (PV) interneurons. We identified an rAAV with moderate (61%) specificity towards PV. By defining additional subtypes of interneurons will constitute the proof of principle that our method can be expanded to other neuronal subtypes. This approach will lead to the development of a toolkit that will further our understanding of brain function and constitute the starting point towards human gene therapy.

Project: Assessing the specificity of expression conferred by enhancers in the context of rAAVs

Mentor: Jordane Dimidschstein, Stanley Center for Psychiatric Research