In vivo selection in non-human primates identifies AAV capsids for on-target CSF delivery to spinal cord

• Published in: Molecular therapy Vol. 32; no. 8; pp. 2584 - 2603
• Main Authors: Hanlon, Killian S., Cheng, Ming, Ferrer, Roberto Montoro, Ryu, Jae Ryun, Lee, Boram, De La Cruz, Demitri, Patel, Nikita, Espinoza, Paula, Santoscoy, Miguel C., Gong, Yi, Ng, Carrie, Nguyen, Diane M., Nammour, Josette, Clark, Sean W., Heine, Vivi M., Sun, Woong, Kozarsky, Karen, Maguire, Casey A.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 07.08.2024; American Society of Gene & Cell Therapy
• Subjects: AAV; AAV capsid libraries; adeno-associated virus; engineered AAV capsids; gene therapy; intrathecal injection; lumbar injection; Original; spinal cord; spinal cord organoids; viral vector; spinal cord organoids; AAV capsid libraries; AAV; engineered AAV capsids; intrathecal injection; gene therapy; adeno-associated virus; viral vector; spinal cord; lumbar injection
• ISSN: 1525-0016; 1525-0024; 1525-0024
• DOI: 10.1016/j.ymthe.2024.05.040

Systemic administration of adeno-associated virus (AAV) vectors for spinal cord gene therapy has challenges including toxicity at high doses and pre-existing immunity that reduces efficacy. Intrathecal (IT) delivery of AAV vectors into cerebral spinal fluid can avoid many issues, although distribution of the vector throughout the spinal cord is limited, and vector entry to the periphery sometimes initiates hepatotoxicity. Here we performed biopanning in non-human primates (NHPs) with an IT injected AAV9 peptide display library. We identified top candidates by sequencing inserts of AAV DNA isolated from whole tissue, nuclei, or nuclei from transgene-expressing cells. These barcoded candidates were pooled with AAV9 and compared for biodistribution and transgene expression in spinal cord and liver of IT injected NHPs. Most candidates displayed increased retention in spinal cord compared with AAV9. Greater spread from the lumbar to the thoracic and cervical regions was observed for several capsids. Furthermore, several capsids displayed decreased biodistribution to the liver compared with AAV9, providing a high on-target/low off-target biodistribution. Finally, we tested top candidates in human spinal cord organoids and found them to outperform AAV9 in efficiency of transgene expression in neurons and astrocytes. These capsids have potential to serve as leading-edge delivery vehicles for spinal cord-directed gene therapies. [Display omitted] IT delivery of AAV vectors results in low on-target delivery to spinal cord and high-off target delivery to the periphery. Maguire and colleagues identify new capsids that mediate a favorable on-target/off-target profile in NHPs and robust transduction of human SCOs.