Cell-Specific Transcriptome Analysis Shows That Adult Pillar and Deiters' Cells Express Genes Encoding Machinery for Specializations of Cochlear Hair Cells

Abstract

The mammalian auditory sensory epithelium, the organ of Corti, is composed of hair cells and supporting cells. Hair cells contain specializations in the apical, basolateral and synaptic membranes. These specializations mediate mechanotransduction, electrical and mechanical activities and synaptic transmission. Supporting cells maintain homeostasis of the ionic and chemical environment of the cochlea and contribute to the stiffness of the cochlear partition. While spontaneous proliferation and transdifferentiation of supporting cells are the source of the regenerative response to replace lost hair cells in lower vertebrates, supporting cells in adult mammals no longer retain that capability. An important first step to revealing the basic biological properties of supporting cells is to characterize their cell-type specific transcriptomes. Using RNA-seq, we examined the transcriptomes of 1,000 pillar and 1,000 Deiters' cells, as well as the two types of hair cells, individually collected from adult CBA/J mouse cochleae using a suction pipette technique. Our goal was to determine whether pillar and Deiters' cells, the commonly targeted cells for hair cell replacement, express the genes known for encoding machinery for hair cell specializations in the apical, basolateral, and synaptic membranes. We showed that both pillar and Deiters' cells express these genes, with pillar cells being more similar to hair cells than Deiters' cells. The fact that adult pillar and Deiters' cells express the genes cognate to hair cell specializations provides a strong molecular basis for targeting these cells for mammalian hair cell replacement after hair cells are lost due to damage.

Clarin‐2 is essential for hearing by maintaining stereocilia integrity and function

“…This shows that the relative abundance of Clrn2 transcripts in the cochlea is stable from late embryonic stages to P12 (the onset of hearing in mice), but thereafter increases (Fig EV4A). Consistent with this finding, in silico analyses of the expression of Clrn2 at different inner ear developmental and adult stages using the gEAR portal ( umgear.org ) reveal that while the Clrn2 transcript is lowly expressed in the newborn inner ear and early postnatal stages, it is readily detected in P15 single‐cell and adult‐sorted hair cells (Liu et al , , ; Ranum et al , ). In addition, the expression of Clrn2 is detected in zebrafish hair cells (Steiner et al , ; Erickson & Nicolson, ).…”

gEAR: gene Expression Analysis Resource portal for community-driven, multi-omic data exploration

“…High-profile, hearingrelated datasets have been made available in the gEAR even before publication, and links to gEAR as the primary method for accessing datasets are ubiquitous within talks/posters at professional conferences. Additionally, the gEAR has already been used for data dissemination 5,[23][24][25][26][27][28][29][30][31][32][33][34][35] , hypothesis generation [36][37][38][39][40][41][42][43][44] and validation of gene expression 29,30,[45][46][47][48][49][50][51][52][53][54][55][56][57] by numerous publications in the ear field. It has also been referenced by numerous groups as a useful tool [58][59][60][61][62][63][64] .…”

“…The gEAR is current curated for the ear field where over 400+ datasets from 6 species and a variety of methodologies are displayed in thematically curated profiles (collections of datasets). 53 . Users can elect to apply a statistical test to the scatter plot comparing data across conditions.…”

Biological insights from multi-omic analysis of 31 genomic risk loci for adult hearing difficulty

“…We generated mRNA-seq from FACS-sorted cochlear epithelial cells, cochlear mesenchymal cells, cochlear neurons, and cochlear vascular endothelial cells in the mouse cochlea. We calculated the median expression of each gene in each of these cell types, as well as in four subtypes of sensory epithelial hair cells and supporting cells derived from published RNA-seq [20][21][22] . For comparison, we considered the expression of each gene in 53 extracochlear human tissues and cell types from the Genotype-Tissue Expression consortium (GTEx) 23 .…”