Project description:Inner ear auditory and vestibular tissues differ in their responses to mechanical stimuli. Chick cochlea and utricle sensory epithelia were microdissected at E20-E21. RNA was extracted and cRNA hybridized to Affymetrix microarrays.
Project description:Age-related hearing impairment (ARHI), one of the most common medical conditions, is strongly heritable, yet its genetic causes remain largely unknown. We conducted a meta-analysis of GWAS summary statistics from multiple hearing-related traits in the UK Biobank (n = up to 323,978) and identified 31 genome-wide significant risk loci for self-reported hearing difficulty (p < 5e-8), of which 30 have not been reported previously at genome-wide significance. We interpreted these loci in the context of newly generated ATAC-seq and single-cell RNA-seq from cells in the mouse cochlea. Risk-associated genes were enriched for expression in cochlear epithelial and non-epithelial cells, as well as for genes related to sensory perception and known Mendelian deafness genes, supporting their relevance to auditory function. Regions of the human genome homologous to open chromatin in sensory epithelial cells from the mouse were strongly enriched for heritable risk for hearing difficulty, even after adjusting for baseline effects of evolutionary conservation and cell-type non-specific regulatory regions. Epigenomic and statistical fine-mapping most strongly supported 50 putative risk genes. Of these, at least 45 were expressed in mouse cochlea and 15 were enriched specifically in sensory hair cells. These results reveal new risk loci and risk genes for hearing difficulty and suggest an important role for altered gene regulation in the cochlear sensory epithelium.
Project description:Purpose and Methods: Cochlear sensory hair cells (HCs) are essential for our sense of hearing. They are embedded in the organ of Corti that lacks regenerative capacity, which is a major cause of hearing loss. However, some neonatal non-sensory cells in the organ of Corti display a limited regenerative ability. We used fluorescence-activated cell sorting (FACS) to isolate different cochlear cell types from postnatal day 2 (P2) mice to assess the individual cell groups’ potential to grow organoids and to generate new HCs. Single-cell RNAseq validated the composition of the cell types in the sorted cell groups. Results and Conclusions: The greater epithelial ridge (GER), a transient tissue that only exists in the neonatal inner ear, harbored the most potent organoid-forming cells. GER-derived organoids expanded into large colonies when cultured adherently and gave rise to new hair cell marker-expressing cells in a sensory epithelia-resembling organization. The organoid forming ability of GER cells was synergistically enhanced when they were cultured at increasing density. The synergistic effect relied on direct cell-to-cell contact rather than released soluble factors.
Project description:Purified utricle hair bundles and utricular epithelium from P3-P7 rat inner ears were analyzed by LC-MS/MS to determine the abundant and enriched proteins of the hair bundle. This dataset used a Thermo LTQ mass spectrometer for protein detection.
Project description:The inner ear utilizes sensory hair cells as mechano-electric transducers for sensing sound and balance. In mammals, these hair cells lack the capacity for regeneration. Unlike mammals, hair cells from non-mammalian vertebrates, such as birds, can be regenerated throughout the life of the organism making them a useful model for studying inner ear genetics pathways. The zinc finger transcription factor GATA3 is required for inner ear development and mutations cause sensory neural deafness in humans. In the avian cochlea GATA3 is expressed throughout the sensory epithelia; however, expression is limited to the striola of the utricle. The striola corresponds to an abrupt change in morphologically distinct hair cell types and a 180° shift in hair cell orientation. We used 3 complimentary approaches to identify potential downstream targets of GATA3 in the avian utricle. Specifically we used microarray expression profiling of GATA3 knockdown by siRNA and GATA3 over-expression treatments as well as direct comparisons of GATA3 expressing cells from the striola and non GATA3 expressing cells from the extra-striola. To identify genes that are co-expressed with GATA3 at the striola reversal zone, we compared gene expression in cells micro-dissected from the sensory epithelia of the chick utricle striola to cells from the surrounding extra-striola. There are 2 biological samples and experiments include technical replicates as well as dye-switches for a total of 8 microarrays.
Project description:The inner ear utilizes sensory hair cells as mechano-electric transducers for sensing sound and balance. In mammals, these hair cells lack the capacity for regeneration. Unlike mammals, hair cells from non-mammalian vertebrates, such as birds, can be regenerated throughout the life of the organism making them a useful model for studying inner ear genetics pathways. The zinc finger transcription factor GATA3 is required for inner ear development and mutations cause sensory neural deafness in humans. In the avian cochlea GATA3 is expressed throughout the sensory epithelia; however, expression is limited to the striola of the utricle. The striola corresponds to an abrupt change in morphologically distinct hair cell types and a 180° shift in hair cell orientation. We used 3 complimentary approaches to identify potential downstream targets of GATA3 in the avian utricle. Specifically we used microarray expression profiling of GATA3 knockdown by siRNA and GATA3 over-expression treatments as well as direct comparisons of GATA3 expressing cells from the striola and non GATA3 expressing cells from the extra-striola. Whole utricle specimens were treated with streptomycin for 24 hrs, rinsed and allowed to recover for an additional 24 hrs. Whole utricles were transfected with either GATA3 or GFP 21mer synthetic siRNAs for an additional 48 hrs and pure sensory epithelia were isolated. There are 2 biological samples and experiments include technical replicates as well as dye-switches for a total of 8 microarrays.