Evolutionary Map of the Postnatal Cochlea Revealed by Single Cell Rna Seq

The postnatal cochlea undergoes significant changes in the mouse leading to the mature hearing organ. Using single-cell RNA sequencing, we explore the cellular and molecular changes that underlie the physiological phenomena. Concentrating on three anatomical loci, we determine the specific origin of type I fibrocytes distinct from type II, III, and IV fibrocytes. Marginal cells have close transcriptional relationships with Reissner’s membrane cell and Spindle cells, and intermediate cells with Schwann cells. Similarly, specific supporting cell populations have close transcriptional relationships with hair cells even as late as P20, suggesting interconversion of these cell groups. Using expression differences in these related cell groupings to identify upstream transcriptional regulators, we identify several transcription factors recognized in syndromic hearing loss. Lastly, we determine genes, in physical proximity to SNPs, identified by GWAS of age-related hearing loss, to be differentially expressed in specific cell populations implying these cells' susceptibility.