Adeno-associated viral vector-mediated expression of NT4-ADNF-9 fusion gene protects against aminoglycoside-induced auditory hair cell loss in vitro

Abstract

Conclusion: The present study suggests that adeno-associated viral vector AAV2-mediated expression of activity-dependent neurotrophic factor-9 (ADNF-9) in the cochlea could be a promising approach to protect the cochlea from aminoglycoside-induced impairment, although a further in vivo study is needed. Objectives: To construct vectors over-expressing ADNF-9 to overcome its short half-life and investigate the effect of ADNF-9 on aminoglycoside-induced hair cell impairment. Methods: We ligated ADNF-9 cDNA to the signal and leader peptides of neurotrophin 4 (NT4) and the fusion gene was named NT4-ADNF-9. NT4-ADNF-9 was subcloned into the prokaryotic expression vector pBV220 to obtain pBV220/NT4-ADNF-9. The induced recombinant ADNF-9 proteins were added into the dorsal root ganglia (DRG) cultures of embryonic day 8 chickens. In addition, we constructed the recombinant vector rAAV-NT4-ADNF-9 and transfected rat neonatal organ of Corti explants in the presence of aminoglycoside G418. Results: Our data showed that the induced expression of ADNF-9 protein could promote cultured DRG neuronal survival and neurite outgrowth. In addition, transfection of rAAV-NT4-ADNF-9 could prevent hair cell loss induced by G418 treatment in the rat organ of Corti.