Expression Patterns of Nedd4 Isoforms and SGK1 in the Rat Cochlea / 听力学及言语疾病杂志

ABSTRACT

Objective To investigate the cellular localization of the neural precursor cell-expressed, developmentally downregulated isoforms(Nedd4), Nedd4- 1/2 and Nedd4- 2, and the serum glucocorticoid- inducible kinasel(SGK1) in various subregions of the rat cochlea. Methods The expression patterns of Nedd4-1/2, Nedd42 and SGK1 in the cochlea of rat were studied by immunohistochemistry with the specific polyclonal rabbit antibodies against the rat Nedd4-1/2, Nedd4-2 and SGK1. Results All three proteins were extensively expressed in various regions of the rat cochlea. They were found in the stria vascularis, spiral ligament, organ of Corti, spiral limbus, spiral ganglion and Reissner's membrane. Conclusion Our findings suggest that there exists a Na+ transport system in the cochlea consisting of SGK1, Nedd4 isoforms and ENaC, which may work in concert to transport Na+ and to maintain homeostasis in the inner ear as they do in other tight epithelia.