Project description:Cre recombinase-mediated conditional knockout of floxed Dicer1 alleles causes depletion of small RNAs including microRNAs, which function to repress target mRNA expression by inhibiting translation and/or stimulating mRNA degradation. We used microarrays to examine gene expression in apical versus basal organ of Corti from the cochleae of control and mutant mice in which Dicer1 was deleted and microRNAs were depleted specifically in sensory hair cells by Atoh1 promoter-driven Cre recombinase expression. Each biological replicate represents the combined apical or combined basal segments of organ of Corti from both cochleae of a single mouse. Two biological replicates for apical and basal organ of Corti from Dicer1 conditonal knockout and littermate controls were collected for RNA extraction and microarray analysis.
Project description:To further understand the biological properties of hair cells of the mammalian cochlea, we examined the transcriptome of adult inner and outer hair cells. Morphologically distinct inner and outer hair cells were isolated from the organ of Corti from adult CBA/J mice. One thousand inner and outer hair cells were separately collected for each biological replicate, using the suction pipette technique. RNA sequencing of two biological replicates of IHCs and three biological replicates of OHCs, each with two technical repeats, was performed. The resulting sequenced reads were mapped. Comparisons between inner and outer hair cells allow identification of enriched genes, as well as differentially expressed genes that result in cellular specialization. Our dataset provides an extensive resource for understanding the molecular mechanisms underlying morphology, function, and pathology of adult mouse inner and outer hair cells.
2018-08-02 | GSE111348 | GEO
Project description:RNA sequencing of adult mouse inner hair cells
Project description:Elmod1 knockout mice develop a severe inner ear defect beginning at early postnatal ages. Cuticular plates of utricle hair cells were initially formed normally, then degenerated after postnatal day 5 (P5). Similarly, hair bundles initially were formed normally, but the cell’s apical membrane subsequently lifted up; fused stereocilia were observed after P5. We used tandem mass tagging to determine whether there were any changes in medium- to high-abundance proteins in mutant animals. No statistically significant differences were seen in any protein quantified with two or more peptides.
Project description:A major cause of human deafness and vestibular dysfunction is permanent loss of the mechanosensory hair cells of the inner ear. In non-mammalian vertebrates such as zebrafish, regeneration of missing hair cells can occur throughout life. While a comparative approach has the potential to reveal the basis of such differential regenerative ability, the degree to which the inner ears of fish and mammals share common hair and supporting cell types remains unresolved. Here we perform single-cell RNA sequencing of the zebrafish inner ear at embryonic through adult stages to catalog the diversity of hair and non-sensory supporting cells. We identify a putative progenitor population for hair and supporting cells, as well as distinct hair and supporting cell types in the maculae versus cristae. The hair and supporting cell types differ from those described for the lateral line, a distributed mechanosensory organ in zebrafish in which most studies of hair cell regeneration have been conducted. In the maculae, we identify two subtypes of hair cells that share gene expression with mammalian striolar or extrastriolar hair cells. In situ hybridization reveals that these hair cell subtypes occupy distinct spatial domains within the two major macular organs, the utricle and saccule, consistent with the reported distinct electrophysiological properties of hair cells within these domains. These findings suggest that primitive specialization of spatially distinct striolar and extrastriolar hair cells likely arose in the last common ancestor of fish and mammals. The similarities of inner ear cell type composition between fish and mammals also support using zebrafish as a relevant model for understanding inner ear-specific hair cell function and regeneration.
Project description:Retinoblastoma gene (Rb1) is required for proper cell cycle exit in the developing mouse inner ear and its deletion in the embryo leads to proliferation of sensory progenitor cells that differentiate into hair cells and supporting cells. In the Pou4f3-Cre:Rb1 flox/flox (Rb1 cKO) inner ear, utricular hair cells differentiate and survive into adulthood whereas differentiation and survival of cochlear hair cells are impaired. To comprehensively survey the pRb pathway in the mammalian inner ear, we performed microarray analysis of Rb1 cKO cochlea and utricle. P6 or 2-month control and Rb1 cKO littermates were euthanized and the inner ear tissues were dissected. Total RNA was extracted from the pooled samples. Technical duplicates of the pooled RNA were used for microarray.
Project description:The inner ear sensory epithelia contain mechanosensitive hair cells and supporting cells. Both cell types arise from SOX2-expressing prosensory cells, but the mechanisms underlying the diversification of these cell lineages remain unclear. To determine the transcriptional trajectory of prosensory cells, we established a SOX2-2A-ntdTomato human ES cell line using CRISPR/Cas9, and performed single-cell RNA-sequencing analysis with SOX2-positive cells isolated from inner ear organoids at various time points between differentiation days 20 and 60. Our pseudotime analysis suggests that hair cells arise primarily from supporting cells, rather than bi-fated transitional cells in organoids. Moreover, ion channel- and ion transporter-related gene sets were enriched in supporting cells vs. prosensory cells, whereas Wnt signaling-related gene sets were enriched in hair cells vs. supporting cells. These findings provide valuable insights into how prosensory cells give rise to hair cells and supporting cells during human inner ear development, and may provide a clue to promote hair cell regeneration from resident supporting cells in individuals with hearing loss and balance disorders.
Project description:The avian utricle, a vestibular organ of the inner ear, displays turnover of sensory hair cells throughout life. This is in sharp contrast to the mammalian utricle, which shows limited regenerative capacity. Here, we use single-cell RNA-sequencing to identify distinct marker genes for the different sensory hair cell subtypes of the chicken utricle, which we validated in situ . We provide markers for spatially distinct supporting cell populations, and identified two transitional cell populations of dedifferentiating supporting cells and developing hair cells. Trajectory reconstruction resulted in an inventory of gene expression dynamics of natural hair cell generation in the avian utricle.