Epigenetic landscape and AAV targeting of human neocortical cell classes

Myriad cell types comprise the human neocortex, but their roles in normal brain function and disease are largely unknown because few tools exist. To find enhancer elements useful for cell type-specific genetic tools, we examined chromatin accessibility in >2,800 high-quality single human neocortical nuclei. Accessible elements frequently are conserved in mouse (34%), often overlap with hypomethylated sites (27%), and connect cell types with neurological diseases via trait-associated SNPs. Directly testing these elements in viral vectors demonstrates functional enhancer activity with cell type specificity predicted by their chromatin accessibility patterns. In summary we present a catalog of human cell class-specific epigenetic elements, and utilize them for new species-agnostic cell type-specific viral genetic tools, which will illuminate human neuron function and drive gene therapy applications.