Mutating PINK1 gene by paired truncated sgRNA/Cas9-D10A in Cynomolgus Monkey

Abstract

Mutations of PINK1 cause early-onset Parkinsons disease (PD) with selective neurodegeneration in humans. However,current PINK1 knockout mouse and pig models are unable to recapitulate the typical neurodegenerative phenotypes observed in PD patients, indicating that it is essential to generate PINK1 disease models in non-human primates (NHPs) that are highly close to humans, to investigate the unique function of PINK1 in primate brains. Paired single guide RNA (sgRNA)/Cas9-D10A nickases and truncated sgRNA/Cas9, both enabling the reduction of the off-target effect without apparently compromising the on-target editing, are two optimized strategies in applying the CRISPR/Cas9 system to establish disease animal models. Here, we combined the two strategies and injected Cas9-D10A mRNA and two truncated sgRNAs into one-cell-stage cynomolgus zygotes to target PINK1 gene. We show precise and efficient gene editing of the target site in the three new born cynomolgus monkeys. The frame shift mutations of PINK1 in mutant fibroblasts leaded to the reduction of the mRNA, However, western-blot and immunofluorescencestaining confirmed the PINK1 proteinlevels werecomparable to that in the wild-type fibroblasts. We further reprogramed mutant fibroblast into induced pluripotent stem cells (iPSCs) and they show similar ability of differentiation into dopamine (DA) neurons. Taken together, our results showed that coinjection of Cas9-D10A nickase mRNA and sgRNA into one-cell-stage cynomolgus embryos enable the generation of human disease models in NHPs and the target editing by paired truncated sgRNA/Cas9-D10A in PINK1 gene exon 2 did not impact the protein expression.