Gentle Isolation of Nuclei from the Brain Tissue of Adult African Turquoise Killifish, a Naturally Short-Lived Model for Aging Research.

Studying brain aging at single-cell resolution in vertebrate systems remains challenging due to cost, time, and technical constraints. Here, we demonstrate a protocol to generate single-nucleus RNA sequencing (snRNA-seq) libraries from the brains of the naturally short-lived vertebrate African turquoise killifish Nothobranchius furzeri. The African turquoise killifish has a lifespan of 4-6 months and can be housed in a cost-effective manner, thus reducing cost and time barriers to study vertebrate brain aging. However, tailored protocols are needed to isolate nuclei of sufficient quality for downstream single-cell experiments from the brain of young and aged fish. Here, we demonstrate an empirically optimized protocol for the isolation of high-quality nuclei from the brain of adult African turquoise killifish, a critical step in the generation of high-quality single nuclei omic libraries. Furthermore, we show that the steps to reduce contaminating background RNA are important to clearly distinguish cell types. In summary, this protocol demonstrates the feasibility of studying brain aging in non-traditional vertebrate model organisms.