[Overexpression of Hath1 induces production of hair cell-like cells in greater epithelial ridge cell cultures from postnatal rat cochlea].

Objective: To investigate the effect of Hath1 (human atonal homolog 1) overexpression on greater epithelial ridge (GER) cells from postnatal rat cochlea in vitro.
Methods: GER cells were isolated by using a combinatorial approach of enzymatic digestion and mechanical separation from P1 rat cochlear. The GER cell cultures were infected by adenovirus containing Hath1 and enhanced green fluorescent protein (ad-Hath1-EGFP), while transfecting EGFP(ad-EGFP) was as controls. Immunostaining were performed at different time points after adenovirus infection.
Results: Some of the infected GER cells became myosin VIIa-positive following ad-Hath1-EGFP infection. The earliest time point to see induction of hair cell differentiation (hair cell marker expression) by ad-Hathl was 5 days post-infection. In contrast, infection of the GER sheet cultures with ad-EGFP control virus did not show any myosin VIIa-positive cells at 3-12 days post-infection in all cultures examined.
Conclusions: GER cells may potentially serve as hair cell progenitors and they are capable of differentiating hair cell-like cells when forced to express Hath1.