A Comprehensive Study of AAV Tropism in the Marmoset Brain

The common marmoset has emerged as an increasingly valuable non-human primate model in neuroscience and biomedical research. Recombinant adeno-associated viruses (AAVs) are powerful tools for gene delivery and gene therapy. However, a systematic comparison of different AAV capsids and delivery routes remains lacking in marmosets. In this study, we constructed a barcoded AAV library comprising 21 capsid variants and administered it to marmosets via intravenous, intraventricular, and intrastriatal injections. To evaluate the AAV tropism, we quantified vector DNA, viral RNA abundance, and tdTomato signals in the marmoset brain and other tissues. Intravenous administration led to limited brain transduction, while intraventricular and intrastriatal administrations demonstrated high transduction efficiency in the marmoset brain. Notably, some AAV capsids exhibited distinct transduction patterns in the marmoset brain. These results offer valuable guidance for optimizing AAV-based gene delivery strategies in marmoset models and support their utility in both basic neuroscience research and potential therapeutic applications.