Adenovirus Vectors Target Several Cell Subtypes of Mammalian Inner Ear In Vivo.

Yilai Shu,Zhengmin Wang,Zheng-Yi Chen,Jun Shen,Yong Tao,Wenyan Li

doi:10.1155/2016/9409846

Abstract

Mammalian inner ear harbors diverse cell types that are essential for hearing and balance. Adenovirus is one of the major vectors to deliver genes into the inner ear for functional studies and hair cell regeneration. To identify adenovirus vectors that target specific cell subtypes in the inner ear, we studied three adenovirus vectors, carrying a reporter gene encoding green fluorescent protein (GFP) from two vendors or with a genome editing gene Cre recombinase (Cre), by injection into postnatal days 0 (P0) and 4 (P4) mouse cochlea through scala media by cochleostomy in vivo. We found three adenovirus vectors transduced mouse inner ear cells with different specificities and expression levels, depending on the type of adenoviral vectors and the age of mice. The most frequently targeted region was the cochlear sensory epithelium, including auditory hair cells and supporting cells. Adenovirus with GFP transduced utricular supporting cells as well. This study shows that adenovirus vectors are capable of efficiently and specifically transducing different cell types in the mammalian inner ear and provides useful tools to study inner ear gene function and to evaluate gene therapy to treat hearing loss and vestibular dysfunction.

Highlights

Irreversible hair cell loss is a major cause of permanent sensorineural hearing loss with no effective treatment
We injected Ad vectors into the neonatal mouse inner ear at postnatal days 0 (P0) or P4 via cochleostomy, because previous studies have shown that injection of associated virus (AAV) into the neonatal mouse cochlea by cochleostomy resulted in efficient transduction in vivo without adversely affecting hearing [8]
We found that the Ad-Cre-green fluorescent protein (GFP)-Baylor transduction was restricted to the injected side and no GFP expression was observed in the uninjected inner ear (Figure 1(d))

Summary

Introduction

Irreversible hair cell loss is a major cause of permanent sensorineural hearing loss with no effective treatment. The development of strategies for hair cell regeneration and for gene delivery has become a major focus in the search for potential therapeutic approaches to restoring hearing [1,2,3]. Inner ear supporting cells and remaining hair cells may reenter the cell cycle and differentiate into new hair cells. One strategy to regenerate hair cells in mammals to restore hearing is to induce surrounding cells especially supporting cells to transdifferentiate into hair cells directly. Another approach is to induce remaining hair cells or supporting cells to reenter the cell cycle and for supporting cells to further differentiate to hair cells [1, 7]. Either approach requires efficient delivery of genes necessary for the induction of these processes into mammalian inner ear cells

Methods

Results

Discussion

Conclusion