Efficient targeting of human glial progenitor cells in vivo with engineered AAV vectors and glymphatic delivery

Treatment of neurological diseases that involve oligodendrocytes or astrocytes would benefit from the selective delivery of viral vectors to their common parent, glial progenitor cells (GPCs). Here, we select adeno-associated virus (AAV) capsids with tropism for human GPCs and demonstrate efficient and widespread delivery of the resultant AAVs throughout the mouse brain through the glymphatic system. In vivo screening of a library of capsid-modified, recombination-reported AAVs in chimeric mice engrafted with PDGFRA-driven Cre recombinase-expressing human GPCs identified a set of AAV5-based vectors that preferentially infect human GPCs and/or their astrocyte and oligodendrocyte progeny in vivo, with minimal systemic infection. To maximize the intracerebral distribution of these vectors while minimizing their dosing and extracerebral spread, we paired intracisternal delivery with systemic hypertonicity to increase glymphatic influx. This method bypasses the blood-brain barrier, delivering AAV directly into the brain parenchyma. Glymphatic delivery of our capsid-modified AAV5s enables efficient transgene delivery to human glia throughout the entire adult mouse brain, with minimal off-target transduction.