AAVR Expression is Essential for AAV Vector Transduction in Sensory Hair Cells

Adeno-associated virus (AAV) vectors are a leading platform for gene therapy. Recently, AAV-mediated gene therapy in the inner ear has progressed from laboratory use to clinical trials, but the lower transduction rates in outer hair cells (OHCs) in the organ of Corti and in vestibular hair cells in adult mice still pose a challenge. OHCs are particularly vulnerable to inner ear insults. In this study, we demonstrated that expression of a key AAV receptor (AAVR, Kiaa0319l, or Au040320) in OHCs and vestibular hair cells decreases significantly in mature mice and AAV particles directly interact with AAVR by forming complexes. Consequently, antibody blockage of AAVR significantly inhibits AAV transduction in sensory hair cells in cochlear explants. Moreover, use of AAVR knockout mice confirms inhibition of AAV transduction in sensory hair cells in vivo. Finally, conditional overexpression of AAVR in sensory hair cells of adult mice successfully restores AAV transduction efficiency in OHCs and vestibular hair cells. In conclusion, this strong evidence that AAVR is essential for AAV transduction in sensory hair cells will help to increase the efficacy of future gene therapy in inner ear.