Differentiation of embryonic stem cells into inner ear vestibular hair cells using vestibular cell derived-conditioned medium

Vestibular hair cells (V–HCs) in the inner ear have important roles and various functions. When V–HCs are damaged, crippling symptoms, such as vertigo, visual field oscillation, and imbalance, are often seen. Recently, several studies have reported differentiation of embryonic stem (ES) cells, as pluripotent stem cells, to HCs, though a method for producing V–HCs has yet to be established. In the present study, we used vestibular cell conditioned medium (V-CM) and effectively induced ES cells to differentiate into V–HCs. Expressions of V-HC-related markers (Math1, Myosin6, Brn3c, Dnah5) were significantly increased in ES cells cultured in V-CM for 2 weeks, while those were not observed in ES cells cultured without V-CM. On the other hand, the cochlear HC-related marker Lmod3 was either not detected or detected only faintly in those cells when cultured in V-CM. Our results demonstrate that V-CM has an ability to specifically induce differentiation of ES cells into V–HCs.