Characterization of rare spindle and root cell transcriptional profiles in the stria vascularis of the adult mouse cochlea

Abstract

The stria vascularis (SV) in the cochlea generates and maintains the endocochlear potential, thereby playing a pivotal role in normal hearing. Knowing transcriptional profiles and gene regulatory networks of SV cell types establishes a basis for studying the mechanism underlying SV-related hearing loss. While we have previously characterized the expression profiles of major SV cell types in the adult mouse, transcriptional profiles of rare SV cell types remained elusive due to the limitation of cell capture in single-cell RNA-Seq. The role of these rare cell types in the homeostatic function of the adult SV remain largely undefined. In this study, we performed single-nucleus RNA-Seq on the adult mouse SV in conjunction with sample preservation treatments during the isolation steps. We distinguish rare SV cell types, including spindle cells and root cells, from other cell types, and characterize their transcriptional profiles. Furthermore, we also identify and validate novel specific markers for these rare SV cell types. Finally, we identify homeostatic gene regulatory networks within spindle and root cells, establishing a basis for understanding the functional roles of these cells in hearing. These novel findings will provide new insights for future work in SV-related hearing loss and hearing fluctuation.

New insights into Perrault syndrome, a clinically and genetically heterogeneous disorder

“…Heatmaps of gene expression across cochlear cell types were generated by utilizing single-nucleus RNA-Seq datasets from the P30 adult mouse SV (Gu et al 2020), singlecell RNA-Seq datasets from P7 mouse organ of Corti (Kolla et al 2020) and P25-P27 mouse spiral ganglion neurons (SGN) (Shrestha et al 2018) (Fig. 3a-c).…”

“…The onset of hearing in mouse occurs at approximately P12. Datasets were normalized using a previously published analysis pipeline (Gu et al 2020). All data were scaled between 0 and 1 using min-max scaling as described (Gu et al 2020).…”

“…Datasets were normalized using a previously published analysis pipeline (Gu et al 2020). All data were scaled between 0 and 1 using min-max scaling as described (Gu et al 2020). Low levels of expression of Perrault syndrome-associated genes can be seen in the stria vascularis (SV) cell types including marginal, intermediate, basal and spindle cells as well as the adjacent root cells and Reissner's cell type (Fig.…”

“…3 Cochlear localization of Perrault syndrome genes using singlecell and single-nucleus RNA-Seq datasets to pinpoint the possible cell types associated with deafness in this genetically heterogenous disorder. Single-cell RNA-Seq datasets from the P7 mouse organ of Corti (Kolla et al 2020) and P25-27 mouse spiral ganglion neurons (Shrestha et al 2018) along with a published P30 adult mouse stria vascularis single-nucleus RNA-seq dataset (Gu et al 2020) were utilized to identify Perrault gene expression levels in the cell types of the inner ear. Heatmaps display Perrault syndrome-associated genes along the vertical axis and cell types are grouped along the horizontal axis.…”

Navigating Hereditary Hearing Loss: Pathology of the Inner Ear

“…1 http://hereditaryhearingloss.org Accordingly, mutations in ion channels and their regulatory subunits that are expressed in the stria vascularis such as KCNQ1, KCNE1, KCNQ10, and BARTTIN or tight junction molecules such as CLDN11 that are required for the integrity of the cell layers lead to the loss of endocochlear potential and consequently the loss of hearing (Gow et al, 2004;Kitajiri et al, 2004;Rickheit et al, 2008;Chen and Zhao, 2014;Chang et al, 2015;Faridi et al, 2019). In terms of novel gene networks operating in the stria vascularis, recent findings using a single cell RNA-seq approach have revealed expression profiles and further subtypes of cells beyond the marginal, intermediate and basal cells (Gu et al, 2020). In addition, known deafness genes that were thought to act elsewhere such as in the organ of Corti were also found to be expressed in the stria vascularis (Korrapati et al, 2019).…”