Mosaic AAV mediates efficient transduction across the central and peripheral nervous systems

Adeno-associated virus (AAV) is a promising vector for neurological gene therapy, yet engineered serotypes are restricted to targeting either the central or peripheral nervous system (CNS or PNS). To overcome this limitation, we generated AAV with mosaic capsid, AAV-PHP.(S + eB), by co-packaging the AAV with two engineered capsid variants: AAV-PHP.eB and AAV-PHP.S, which exhibits strong CNS tropism and PNS tropism, respectively. Systemic administration of AAV-PHP.(S + eB) in adult mice mediated widespread transgene expression throughout the CNS, comparable to AAV-PHP.eB, while simultaneously achieving robust transduction of dorsal root ganglia neurons, similar to AAV-PHP.S. Notably, the mosaic vector demonstrated significantly reduced off-target transduction in the liver compared to both parental vectors, suggesting an improved safety. These results indicate that mosaic capsid assembly is a potent strategy for designing dual-tropic AAV vectors without increasing viral dose. This approach holds significant promise for treating complex neurological disorders that involve both nervous system compartments.