Provided are compositions and methods for inducing the self-renewal of stem/progenitor supporting cells, including inducing the stem/progenitor cells to proliferate while maintaining, in the daughter cells, the capacity to differentiate into hair cells, and including compositions and methods of using GSK3-alpha inhibitors, and salts thereof, optionally in combination with a Differentiation Inhibitor such as a Notch agonist or an HDAC inhibitor (e.g., valproic acid).
