Regeneration of Cochlear Hair Cells in Adult Mice by Chemical Mediated Reprogramming

Abstract Strategies to overcome irreversible cochlear hair cell (HC) damage and loss are of vital importance to develop treatment for hearing loss. In mature mammalian cochlea, Myc and Notch1 co-activation reprograms supporting cells (SC) for HC regeneration. To understand the mechanisms underlying reprogramming, we performed single cell RNAseq and uncovered the pathways including Wnt and cAMP, whose blockade attenuate HC regeneration. We screened and identified a combination (the cocktail) of drug-like compounds of small molecules and siRNAs to activate the pathways of Myc, Notch1, Wnt and cAMP. We show that the cocktail effectively replaces Myc and Notch1 transgenes to reprogram adult wildtype supporting cells for HC regeneration in vitro. Finally, we demonstrate the cocktail is capable of reprogramming adult cochlea for HC regeneration in wild-type mice with hair cell loss in vivo. Our study identified a strategy by a clinically-relevant approach to reprogram mature inner ear for HC regeneration, laying the foundation for hearing restoration by HC regeneration.