Overloaded Adeno-Associated Virus as a Novel Gene Therapeutic Tool for Otoferlin-Related Deafness


Rankovic V, Vogl C, Dörje N M, Bahader I, Duque-Afonso C J, Thirumalai A, Weber T, Kusch K, Strenzke N, Moser T


Frontiers in Molecular Neuroscience


Front. Mol. Neurosci. 13:600051.


Hearing impairment is the most common sensory disorder in humans. So far, rehabilitation of profoundly deaf subjects relies on direct stimulation of the auditory nerve through cochlear implants. However, in some forms of genetic hearing impairment, the organ of Corti is structurally intact and therapeutic replacement of the mutated gene could potentially restore near natural hearing. In the case of defects of the otoferlin gene (OTOF), such gene therapy is hindered by the size of the coding sequence (~6 kb) exceeding the cargo capacity (<5 kb) of the preferred viral vector, adeno-associated virus (AAV). Recently, a dual-AAV approach was used to partially restore hearing in deaf otoferlin knock-out (Otof-KO) mice. Here, we employed vitro and vivo approaches assess gene-therapeutic potential naturally-occurring newly-developed synthetic AAVs overloaded with full-length Otof coding sequence. Upon early postnatal injection into cochlea Otof-KO mice, drove specific expression approximately 30% all IHCs, as demonstrated by immunofluorescence labeling polymerase chain reaction. Recordings auditory brainstem responses behavioral assay partial restoration hearing. Together, our results suggest that gene therapy DFNB9 – using single AAV vector is indeed feasible, reducing complexity transfer compared approaches.