Transcriptomes of cochlear inner and outer hair cells from adult mice

Abstract

Inner hair cells (IHCs) and outer hair cells (OHCs) are the two anatomically and functionally distinct types of mechanosensitive receptor cells in the mammalian cochlea. The molecular mechanisms defining their morphological and functional specializations are largely unclear. As a first step to uncover the underlying mechanisms, we examined the transcriptomes of IHCs and OHCs isolated from adult CBA/J mouse cochleae. One thousand IHCs and OHCs were separately collected using the suction pipette technique. RNA sequencing of IHCs and OHCs was performed and their transcriptomes were analyzed. The results were validated by comparing some IHC and OHC preferentially expressed genes between present study and published microarray-based data as well as by real-time qPCR. Antibody-based immunocytochemistry was used to validate preferential expression of SLC7A14 and DNM3 in IHCs and OHCs. These data are expected to serve as a highly valuable resource for unraveling the molecular mechanisms underlying different biological properties of IHCs and OHCs as well as to provide a road map for future characterization of genes expressed in IHCs and OHCs.

RBP2 stabilizes slow Cav1.3 Ca2+ channel inactivation properties of cochlear inner hair cells

“…This was in line with a study showing an upregulation of brain RBP1 and RBP2 levels during brain development (P0-P15), while RBP3 levels were low and unchanged [41]. Since a recent transcriptome analysis [35] reported much higher levels of RBP2 compared to RBP3 in IHCs, high RBP3 expression has been found primarily outside the nervous system (mainly in mouse testis [41,72]), and validated specific antibodies for mouse RBP3 are not available, we decided to focus on the RBP2 isoform and studied its localization in mouse IHCs. Indeed, Cav1.3 α1 subunits co-localized with RBP2 in IHCs as shown by double immunofluorescence labeling and confocal microscopy in IHCs of 4-week-old mice.…”

“…Although β2 deficiency reduces current densities by about 70%, VDI remains unaffected in residual Cav1.3 currents [42]. This points toward other mechanisms that stabilize slow VDI also of Cav1.3 channels associated with other β subunits, such as β3 [42], which has been consistently detected in IHCs by PCR [33,42] and transcriptome analysis [35,37]. Also alternative splicing of Cav1.3 α1 subunits has pronounced effects on Cav1.3 inactivation, but this mainly affects CDI as shown for C-terminal alternative splicing into long (Cav1.3 L ) and several short variants, without a major impact on VDI [57,62,70].…”

Pou4f1 Defines a Subgroup of Type I Spiral Ganglion Neurons and Is Necessary for Normal Inner Hair Cell Presynaptic Ca2+ Signaling

“…In contrast, no puncta were observed in hair cells or supporting cells at either time point. Next, we used the gEAR portal to query four recently published RNAseq datasets (Cai et al, 2015;Elkon et al, 2015;Li et al, 2018;Wiwatpanit et al, 2018) in which hair cells had been isolated at P0 or from adults using fluorescence activated cell sorting (FACS) or visual collection. For comparison, the expression levels of three known hair-cell-specific genes (Pou4f3, Gfi1, Myo7a) were compared with Pou4f1.…”

Calcium induced calcium release in proximity to hair cell BK channels revealed by PKA activation

“…Interrogation of prior published chicken Affymetrix datasets reveals that ITPR1, 2, and 3 are all detected in the basilar papilla (Frucht et al, 2011). Similarly, RYR1, 2 and 3 are all detected in the basilar papilla with no significant differential distribution of these receptors along the tonotopic axis (Itpr1, Itpr2, and Ryr1 are also expressed in mouse inner and outer hair cells) (Frucht et al, 2011;Li et al, 2018). In addition to the effects on ITPRs and ryanodine receptors, PKA also modulates phospholipase C (PLC) and couples it to receptors strengthening CICR (Liu and Simon, 1996).…”