Sonic hedgehog promotes mouse inner ear progenitor cell proliferation and hair cell generation in vitro

Sonic hedgehog (Shh) signaling is essential for auditory cell fate determination and inner ear dorsal/ventral patterning during development. Here, we show that Shh accelerates inner ear progenitor cell proliferation, and the inhibitor of Shh signaling cyclopamine reduces mitotic growth of otocyst cells in vitro. The number of hair cells in cultures of inner ear progenitor cells that were treated with Shh was significantly higher than that in control cultures. When Shh signaling was blocked with cyclopamine, hair cell generation was largely inhibited. Our results suggest that Shh may be a regulator of inner ear progenitor cell growth and hair cell generation.