The CRISPR/Cas9 gene editing system has been widely used in the basic biomedical research. However, the preclinical safety of the CRISPR/Cas9 system lacks a comprehensive assessment. Previous studies have shown that the CRISPR/Cas9 system causes a large number of off-target mutations in mice, and the studies of cell lines has found that there are large structural variations in the target regions of the genome in Cas9-edited cells. However, the results of these studies are still controversial due to the aspects of experimental design and data analysis.
Macaca mulatta as non-human primates with the nearest genetic manipulation to human evolutionary relationships, so exploring the off-target effect of Cas9 gene editing in macaque disease models is crucial for future clinical applications.The journal Nature Communications has published a paper showed that nascent mutations found in the CRISPR/Cas9 gene-editing monkey were randomly distributed in the genome and did not land on the predicted potential off-target locations.
A macaque model of microcephaly gene-MCPH1 knockout was constructed by using the CRISPR/Cas9 system. Through deep second-generation sequencing and analysis of multiple knockout monkeys and their wild-type parents, it was found that Cas9 did not cause a large number of nascent mutations in the primate genome. In addition, using the long fragment sequencing technology, the target regions of MCPH1 gene were sequenced and analyzed in depth, and it was found that there was no structural variation of large fragments in the target regions.
The above research results show that the CRISPR/Cas9 gene editing system does not cause significant off-target effect in primates, and has relatively high safety.