Adenine base editing

Retinal pigment epithelium (RPE) located at the back of the eye is essential for vision. It supports the photoreceptors, providing molecules required for their function. One of the main proteins produced by the RPE and indispensable for vision is the RPE65 enzyme, which is responsible for chemical signaling at the initial step of visual processing. De novo nonsense mutations in the Rpe65 gene underlie inherited genetic disorders of the eyes, resulting in blindness. To address this problem, we have harnessed the power of adenine base editors (ABEs) with Cas9 – single-guide RNA machinery to target  the mutations in the Rpe65 gene for their repair. We delivered genes coding for ABEs and the Cas9 system subretinally via a lentiviral vector. Our therapeutic manipulation corrected the pathogenic mutation in a mouse model with up to 29% efficiency and with minimal formation of indel and off-target mutations. The ABE-treated mice displayed restored RPE65 expression and its activity in the visual cycle. Moreover, we have observed near-normal levels of retinal and visual functions. Our findings motivate the further testing of ABEs for the treatment of inherited retinal diseases and for the correction of pathological mutations with non-canonical protospacer-adjacent motifs.


dr Andrzej Foik, e-mail: afoik@ichf.edu.pl & dr Anna Posłuszny, e-mail: aposluszny@ichf.edu.pl

Pertinent published article:

Restoration of visual function in adult mice with an inherited retinal disease via adenine base editing

Susie Suh, Elliot H. Choi, Henri Leinonen, Andrzej T. Foik, Gregory A. Newby, Wei-Hsi Yeh, Zhiqian Dong, Philip D. Kiser, David C. Lyon, David R. Liu & Krzysztof Palczewski, Nat Biomed Eng. 2021 Feb;5(2):169-178.