Spontaneous regeneration of cochlear supporting cells after neonatal ablation ensures hearing in the adult mouse

Significance The auditory sensory epithelium contains two major cell types: hair cells and supporting cells. Mammalian auditory hair cells do not regenerate after damage or loss, resulting in permanent hearing impairment. How supporting cell loss affects auditory function remains to be determined. Here, we demonstrate that inner border and inner phalangeal cells, the two types of supporting cells surrounding inner hair cells, can be replenished completely after selective ablation in the neonatal cochlea, allowing hearing to be preserved. Our findings challenge the view that mammalian auditory sensory epithelium has limited intrinsic regenerative capacity and provide previously unindetified opportunities for replacement of damaged auditory cells and restoration of hearing.