Huan Qin, Wenliang Zhang, Shiyao Zhang, Yuan Feng, Weihui Xu, Jia Qi, Qian Zhang, Chunxiu Xu, Shanshan Liu, Jia Zhang, Yushuang Lei, Wanqin Liu, Shuyu Feng, Jingjing Wang, Xuefei Fu, Zifen Xu, Ping Li, Kai Yao; Vision rescue via unconstrained in vivo prime editing in degenerating neural retinas. J Exp Med 1 May 2023; 220 (5): e20220776. doi: https://doi.org/10.1084/jem.20220776
Retinitis pigmentosa (RP) is an inherited retinal dystrophy causing progressive and irreversible loss of retinal photoreceptors. Here, we developed a genome-editing tool characterized by the versatility of prime editors (PEs) and unconstrained PAM requirement of a SpCas9 variant (SpRY), referred to as PESpRY. The diseased retinas of Pde6b-associated RP mouse model were transduced via a dual AAV system packaging PESpRY for the in vivo genome editing through a non-NGG PAM (GTG). The progressing cell loss was reversed once the mutation was corrected, leading to substantial rescue of photoreceptors and production of functional PDE6β. The treated mice exhibited significant responses in electroretinogram and displayed good performance in both passive and active avoidance tests. Moreover, they presented an apparent improvement in visual stimuli-driven optomotor responses and efficiently completed visually guided water-maze tasks. Together, our study provides convincing evidence for the prevention of vision loss caused by RP-associated gene mutations via unconstrained in vivo prime editing in the degenerating retinas.
Retinitis pigmentosa (RP) is characterized by progressing retinal degeneration and represents one of the major causes of blindness throughout the world, with an estimated incidence of one in 4,000 human births (Hartong et al., 2006; Verbakel et al., 2018). To date, a variety of mutations in more than 100 genes such as phosphodiesterase 6b (PDE6b) have been found to be associated with this devastating inherited retinal disorder (IRD; Daiger et al., 2013; Gagliardi et al., 2019; https://sph.uth.edu/retnet/). The degeneration in diseased retinas begins with the initial dysfunction of dim light-sensing rod photoreceptors distributed throughout the retina, followed by the onset of secondary death of cone photoreceptors present with the highest density at the center of macula and accounting mainly for the color vision, and leads to severe and irreversible deterioration of vision and eventual blindness.