Characterization of the development of the mouse cochlear epithelium at the single cell level

Mammalian hearing requires the development of the organ of Corti, a sensory epithelium comprising unique cell types. The limited number of each of these cell types, combined with their close proximity, has prevented characterization of individual cell types and/or their developmental progression. To examine cochlear development more closely, we transcriptionally profile approximately 30,000 isolated mouse cochlear cells collected at four developmental time points. Here we report on the analysis of those cells including the identification of both known and unknown cell types. Trajectory analysis for OHCs indicates four phases of gene expression while fate mapping of progenitor cells suggests that OHCs and their surrounding supporting cells arise from a distinct (lateral) progenitor pool. Tgf beta r1 is identified as being expressed in lateral progenitor cells and a Tgf beta r1 antagonist inhibits OHC development. These results provide insights regarding cochlear development and demonstrate the potential value and application of this data set. How the development of the cochlear epithelium is regulated is unclear. Here, the authors use single cell RNAseq analysis to provide insight into the transcriptional changes arising during development of the murine cochlear inner and outer hair cells.