Adenine Base Editing in vivo with a Single Adeno-Associated Virus Vector [article]

Han Zhang, Nathan Bamidele, Pengpeng Liu, Ogooluwa Ojelabi, Xin D. Gao, Tomas Rodriguez, Haoyang Cheng, Scot A. Wolfe, Wen Xue, Erik J. Sontheimer
2021 bioRxiv   pre-print
Base editors (BEs) have opened new avenues for the treatment of genetic diseases. However, advances in delivery approaches are needed to enable disease targeting of a broad range of tissues and cell types. Adeno-associated virus (AAV) vectors remain one of the most promising delivery vehicles for gene therapies. Currently, most BE/guide combinations and their promoters exceed the packaging limit (~5 kb) of AAVs. Dual-AAV delivery strategies often require high viral doses that impose safety
more » ... rns. In this study, we engineered an adenine base editor using a compact Cas9 from Neisseria meningitidis (Nme2Cas9). Compared to the well-characterized Streptococcus pyogenes Cas9-containing ABEs, Nme2-ABE possesses a distinct PAM (N4CC) and editing window, exhibits fewer off-target effects, and can efficiently install therapeutically relevant mutations in both human and mouse genomes. Importantly, we showed that in vivo delivery of Nme2-ABE and its guide RNA by a single-AAV vector can revert the disease mutation and phenotype in an adult mouse model of tyrosinemia. We anticipate that Nme2-ABE, by virtue of its compact size and broad targeting range, will enable a range of therapeutic applications with improved safety and efficacy due in part to packaging in a single-vector system.
doi:10.1101/2021.12.13.472434 fatcat:ked6pgixtbbsdnq5t7vc7xgeg4