AAV-CRISPR Gene Editing Is Negated by Pre-existing Immunity to Cas9

作者：Ang Li, Mark R. Tanner, Ciaran M. Lee, Ayrea Hurley, Marco De Giorgi, Kelsey E. Jarrett, Timothy Davis, Alexandria M. Doerfler, Gang Bao, Christine Beeton, William R. Lagor · 发表于：Molecular Therapy · 年份：2020 · DOI：10.1016/j.ymthe.2020.04.017 · 被引用次数：231 · 研究领域：CRISPR and Genetic Engineering、Virus-based gene therapy research、Viral Infections and Immunology Research

Adeno-associated viral (AAV) vectors are a leading candidate for the delivery of CRISPR-Cas9 for therapeutic genome editing in vivo . However, AAV-based delivery involves persistent expression of the Cas9 nuclease, a bacterial protein. Recent studies indicate a high prevalence of neutralizing antibodies and T cells specific to the commonly used Cas9 orthologs from Streptococcus pyogenes (SpCas9) and Staphylococcus aureus (SaCas9) in humans. We tested in a mouse model whether pre-existing immunity to SaCas9 would pose a barrier to liver genome editing with AAV packaging CRISPR-Cas9. Although efficient genome editing occurred in mouse liver with pre-existing SaCas9 immunity, this was accompanied by an increased proportion of CD8 + T cells in the liver. This cytotoxic T cell response was characterized by hepatocyte apoptosis, loss of recombinant AAV genomes, and complete elimination of genome-edited cells, and was followed by compensatory liver regeneration. Our results raise important efficacy and safety concerns for CRISPR-Cas9-based in vivo genome editing in the liver.