Project description:Transcriptome analysis of human inner ear tissue Hearing loss is common and caused by a wide range of molecular and cellular pathologies. Current diagnosis of hearing loss depends of a combination of physiologic testing, patient history and in some cases genetic testing. Currently no biopsy or equivalent procedure exists to diagnose inner ear disorders. The goal of this study was to determine if miRNAs could be identified in human perilymph potentially leading to the development of biomarkers for inner ear disease. Analysis of miRNAs was carried out by evaluating miRNA targets in a cochlear transcriptome library (GSE128505) derived from human inner ear tissue harvested during surgery in which the inner ear is removed.
Project description:Deprivation of peripheral nerve input by cochlear removal in young mice results in dramatic neuron death in the cochlear nucleus (CN). The same manipulation in older mice does not result in significant loss. The molecular basis of this critical period of vulnerability remains largely unknown. Here we identified genes regulated at early time points after cochlear removal at ages when neurons are vulnerable (postnatal day (P)7) or invulnerable (P21) to this challenge. Afferent deprivation regulated very different sets of genes at P7 and P21. These genes showed a variety of functions at both ages, but surprisingly there was no net increase in pro-apoptotic genes at P7. A large set of upregulated immune-related genes was identified at P21. Keywords: Time Course after Cochlear Removal, Age Comparison
Project description:The cochlear nucleus is the first central pathway involved in the processing of peripheral auditory activity. It is heterogeneous in neuronal populations and physiologic responses and is organized in three major subdivisions: the anterior ventral cochlear nucleus (AVCN), the posterior ventral cochlear nucleus (PVCN) and the dorsal cochlear nucleus (DCN). Although each region demonstrates multiple cell types and functions, there are predominant populations of neurons in each region that underlie the principal role each subdivision plays in auditory processing. Little is known of the underlying genetic contribution to these properties. This study sought to identify genes expressed in the subdivisions of the cochlear nucleus that may account for the anatomical and physiological characteristics of each subdivision. These data provide a genetic basis for understanding normal auditory processing in the cochlear nucleus and a template for investigating changes that may occur with hearing loss, the generation and percept of tinnitus, and central processing disorders. Keywords: normal, comparative Brown Norway rats (n=40, female, 45days) were anesthetized and decapitated. Brains were rapidly removed and the subdivisions of the cochlear nucleus (AVCN, PVCN and DCN) dissected on dry ice. Total RNA was extracted and tested for concentration and purity by spectrophotometry and integrity by gel electrophoresis. SAGE was performed using the NlaIII enzyme and Invitrogen SAGE kit. Concatemers were commercially sequenced and imported into eSAGE (Margulies and Innis, 2000) for tag extraction and frequency.
Project description:To understand the molecular control of development and regeneration in the mammalian cochlear sensory epithelia, we performed a comparative study of gene expression patterns between postnatal day-3 (P3) and adult stages using a microarrays approach.
Project description:Overall goal of the study is to identify genes with enriched expression in cochlear macrophages that were also regulated in an age-dependent manner
Project description:Fragile X Syndrome (FXS) is a hereditary form of autism spectrum disorder. It is caused by a trinucleotide repeat expansion in the Fmr1 gene, leading to a loss of Fragile X Protein (FMRP) expression. The loss of FMRP causes auditory hypersensitivity: FXS patients display hyperacusis and the Fmr1- knock-out (KO) mouse model for FXS exhibits auditory seizures. FMRP is strongly expressed in the cochlear nucleus and other auditory brainstem nuclei. We hypothesize that the Fmr1-KO mouse has altered gene expression in the cochlear nucleus that may contribute to auditory hypersensitivity.
Project description:CMP-Neu5Ac hydroxylase (Cmah) disruption caused several abnormalities and diseases including hearing loss in old age. However, underling molecular mechanisms that give rise to age-related hearing loss (AHL) in Cmah-null mouse are still obscure. To identify differential gene expression profiles associated with Cmah disruption, we performed microarray analysis using Illumina MouseRef-8 v2 Expression BeadChip, using the cochlear tissues from a control mouse and a Cmah-null mouse. Total RNA was extracted and purified from the cochlear tissues of WT and Cmah-null mice using RNeasy columns (Qiagen; Valencia, CA, USA) according to the manufacturer’s protocol. The RNA quality was verified using an Agilent Bioanalyzer 2100 (Agilent Technologies; Palo Alto, CA, USA) using the RNA 6000 Pico Assay. Generation of double-stranded cDNA, preparation and labeling of cRNA, hybridization to Mouse Ref-8 v2.0 Expression BeadChip (Illumina, Inc.; San Diego, CA, USA), washing, and scanning were all performed according to the standard Illumina protocol. Arrays were scanned using the Illumina Bead Array Reader Confocal Scanner.
Project description:A balance of morphogen gradients during embryogenesis is thought to determine the identity of inner ear end organs. We applied this developmental principle to aggregates of human pluripotent stem cells and found that modulations of Sonic Hedgehog and WNT signaling promote stem cell-derived otic progenitors to express ventral otic markers. Strikingly, these ventralized otic progenitors gave rise to hair cells with short hair bundles comprised of stereocilia arrayed in a geometry reminiscent of cochlear hair cells. Moreover, these ventralized hair cells expressed multiple markers defining outer or inner hair cells in the cochlea. These results reveal that early morphogenic signals are sufficient for not only establishing cochlear gene expression, but also defining structural properties pertaining to the cochlear sensory epithelium.