Project description:This study demonstrates the baseline data of gradient gene expression in the cochlea. Especially for genes whose mutations cause autosomal dominant non syndromic hearing loss (Pou4f3, Slc17a8, Tmc1, and Crym) as well as genes important for cochlear function (Emilin-2 and Tectb), gradual expression changes help to explain the various pathological conditions. Four C57BL/6 mice aged 6 weeks cochlea samples including the lateral wall, stria vascularis, spiral ligament, spiral prominence, and the organ of corti were dissected and separated into the apical, middle and basal turns to compare gene expression profiles of each cochlea turn.
Project description:The cochlear duct is tonotopically organized, such that the basal cochlea responds more sensitively to high frequency sounds and the apical cochlea to low frequency sounds. In effort to understand how the tonotopic organization is established in mammals, we searched for genes that are differentially expressed along the tonotopic axis during neonatal development. Eighty temporal bones were dissected from C57BL/6 mice at P0 and P8. The cochlear tissues were divided into three equal pieces representing the basal, middle and apical turns, and pooled separately. Six total RNA from the pooled samples were applied to 6 GeneChips.
Project description:The cochlear duct is tonotopically organized, such that the basal cochlea responds more sensitively to high frequency sounds and the apical cochlea to low frequency sounds. In effort to understand how the tonotopic organization is established in mammals, we searched for genes that are differentially expressed along the tonotopic axis during neonatal development.
Project description:A rat model of acute mitochondrial dysfunction in the cochlea is created by applying an irreversible mitochondrial complex II enzyme inhibitor, 3-NP, directly to the round window membrane. Treatment with 300 mM 3-NP results in temporary hearing loss (temporary threshold shift (TTS) model), whereas treatment with 500 mM 3-NP results in profound and permanent hearing loss (permanent threshold shift (PTS) model. Either treatment results with a primary histological change in the lateral wall spiral ligament. Because local ATP deprivation in the inner ear results from inhibition of inner ear mitochondrial function, this model replicates the etiology of inner ear energy failure caused by ATP deprivation due to inner ear ischemia. We used microarrays to detail the global programme of gene expression in the damaged cochlear lateral wall by 3NP and identified distinct classes of up-regulated/ down-regulated genes during the process. One and three day after administrated either 300 mM of 3-NP (TTS-1d and TTS-3d, respectably) or saline (Ctrl-1d and Ctrl-3d, respectably), rat cochear lateral wall in the apical side of the basal turn was harvested for RNA extraction and hybridization on Affymetrix microarrays.
Project description:This study investigates how lead exposure triggers cochlear synaptopathy and hearing loss in mice. Young-adult CBA/J mice were given lead acetate in drinking water for 28 days. We assessed hearing thresholds, outer hair cell activity, and synaptic changes in the cochlea. Lead exposure raises hearing thresholds, indicating cochlear synaptopathy. Notably affects synapses in the basal turn without impacting outer hair cells. In addition to this, lead altered the abundance of 352 synaptic proteins, with the synaptic vesicle cycle pathway prominently affected. Lead-induced cochlear synaptopathy targets basal cochlear regions, implicating synaptic vesicle cycle signaling in hearing loss. Revealing specific mechanisms behind lead-induced hearing deficits enhances targeted interventions and preventive strategies, advancing our understanding of lead induced hearing loss.
2024-10-17 | PXD050415 | Pride
Project description:RNA sequencing of apical and basal inner hair cells
Project description:We analyzed the transcriptomes of 30 isolated apical OHCs and basal OHCs from rat cochlea, and the results showed that more than 50 genes were differentially expressed and 20 genes were uniquely expressed among these populations. We analyzed these genes with a focus on their functions related to cellular structure and transmembrane channels and their vulnerability to and involvement in hereditary deafness caused by OHC defects. Our results could serve as a guideline for exploring the molecular mechanisms underlying the biological properties of OHCs.