Clonal Expansion of Lgr5-Positive Cells from Mammalian Cochlea and High-Purity Generation of Sensory Hair Cells

Death of cochlear hair cells, which do not regenerate, is a cause of hearing loss in a high percentage of the population. Currently, no approach exists to obtain large numbers of cochlear hair cells. Here, using a small-molecule approach, we show significant expansion (>2,000-fold) of cochlear supporting cells expressing and maintaining Lgr5, an epithelial stem cell marker, in response to stimulation of Wnt signaling by a GSK3β inhibitor and transcriptional activation by a histone deacetylase inhibitor. The Lgr5-expressing cells differentiate into hair cells in high yield. From a single mouse cochlea, we obtained over 11,500 hair cells, compared to less than 200 in the absence of induction. The newly generated hair cells have bundles and molecular machinery for transduction, synapse formation, and specialized hair cell activity. Targeting supporting cells capable of proliferation and cochlear hair cell replacement could lead to the discovery of hearing loss treatments. [Display omitted] •Lgr5+ cochlear supporting cells undergo clonal expansion after drug treatment•Colonies of Lgr5+ cells generate sensory hair cells in high yield•Hair cells can be generated from cells of the adult mouse and primate cochlea•Expansion of Lgr5+ cells and hair cells can be achieved in situ in the cochlea Generation of hair cells after damage to the cochlea is a potential treatment for deafness. McLean et al. demonstrate that Lgr5+ supporting cells dissociated from the cochlear sensory epithelium form organoids and differentiate into hair cells in high yield after treatment with a combination of growth factors and drugs.