Enhancer AAV toolbox for accessing and perturbing striatal cell types and circuits

Area of Science:

• Neuroscience
• Molecular Biology
• Genetics

Background:

• The striatum is crucial for motor control, reward, and habit formation.
• Existing tools for studying striatal cell types and circuits have limitations in specificity and versatility.
• Targeting specific neuronal populations within the striatum is essential for understanding its complex functions.

Purpose of the Study:

• To create and validate a comprehensive Adeno-Associated Virus (AAV) enhancer toolbox for precise targeting of striatal cell types and circuits.
• To enable cell-type-specific perturbations and analyses in the striatum.
• To demonstrate the utility of these tools in various experimental contexts and across different mammalian species.

Main Methods:

• Curated and validated a suite of enhancer AAV vectors targeting major striatal neuron populations (MSNs, interneurons).
• Assessed vector specificity using molecular validation, diverse delivery routes, and various transgene cargos.
• Demonstrated optogenetic perturbation of behavior and multiplex labeling of interneuron types.
• Validated *in vivo* enhancer activity in rodent and non-human primate models.

Main Results:

• Developed best-in-class AAV vectors for specific access to medium spiny neurons (MSNs), direct/indirect pathway MSNs, and interneurons (Sst-Chodl, Pvalb-Pthlh, cholinergic).
• Confirmed high specificity and reliability of AAV vectors across different delivery methods and experimental conditions.
• Successfully demonstrated circuit-selective optogenetic control of behavior and multiplexed labeling of striatal interneurons.
• Showcased conserved *in vivo* activity of MSN enhancers in both rat and macaque models.

Conclusions:

• The presented enhancer AAV toolbox provides unprecedented versatility for striatal cell type and circuit research.
• These tools overcome limitations of traditional transgenic models, offering broader applicability.
• The toolbox facilitates cell-type-specific studies and circuit perturbations in diverse mammalian species, advancing the field of neuroscience.