AAV8-mediated CasRx delivery and expression in the cochlea and cochlear nucleus of mice

CRISPR/Cas9 based gene editing has made great strides in recent years, enabling the treatment of a wide range of genetic diseases, including hearing loss in congenitally deaf mice. While current successful cases of gene editing for hereditary deafness might induce off-target mutations in DNA sequences，restricting to clinical translational application. CasRx, a recently discovered member of the type VI CRISPR system, only modifies the expression of target RNA without affecting the DNA to avoid off-target mutations resulting from gene editing, holding broad application prospects. Here, we used AAV8 to successfully mediated CasRx expression in the cochleae and cochlear nucleus of C57BL/6J mice. Two weeks after viral injection, it remained normal for the number and morphology of neurons and other types of cells in the cochlear nucleus. Importantly, the hearing performance measured in ABR thresholds also remained normal after viral injection, indicating the safety of RNA editing in the cochleae and cochlear nucleus. In conclusion, we firstly accomplished AAV-CasRx mediated RNA editing in cochlear nucleus of mice, proving safe for treatment of cochlear nucleus related diseases such as tinnitus and hearing loss.