Adeno-associated virus-mediated gene transfer to hair cells and support cells of the murine cochlea

More than 28 million Americans suffer from various forms of hearing loss. The lack of effective treatments for many forms of hearing disorders has prompted interest in the potential application of gene delivery techniques to treat both inherited and pathological hearing disorders. However, to develop a gene therapy strategy that will successfully treat hearing disorders, appropriate vectors that are capable of transducing cochlear hair cells and support cells must be identified. In the present study, we examined the efficiency with which AAV vectors (serotypes 1, 2, and 5) transduce hair cells and support cells in cochlear explants from P0 and E13 mice. We further examined the ability of the CBA and GFAP promoters to drive expression of a GFP marker gene in hair cells and support cells. Robust GFP expression was observed in hair cells and support cells following transduction of primary murine cochlear explants with AAV serotypes 1 and 2, but not serotype 5. The CBA promoter predominantly drove GFP expression in hair cells. In contrast, strong expression from the GFAP promoter was observed primarily in support cells. Thus, using AAV vectors and specific promoters, cell-type-specific expression of transgenes can be established within the cochlea.