ABSTRACT: 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:Age-related hearing loss is a progressive sensorineural hearing loss that occurs as people get older. Degeneration of the organ of Corti and atrophy of the lateral wall of the cochlear duct (or scala media) in the inner ear are the two primary causes. MicroRNAs (miRNAs), a class of short non-coding RNAs that regulate the expression of mRNA/protein targets, are important regulators of cellular senescence and aging. We examined the change of miRNA gene expression profiles in the lateral wall of the cochlear duct in two mouse strains during aging The totoal RNA was extracted from the lateral wall of cochlear duct from CBA/J and C57BL/6J mice at different ages. The expression profile of miRNAs was examined by miR microarray GeneChip.
Project description:In order to elucidate molecular mechanisms of noise-induced hearing loss in the cochlea (inner ear), transcriptome of the cochlear sample was analyzed after induction of hearing loss by exposure to intense noise in mice. Cochlear transcriptome was analyzed at 3 hours following the noise exposure.
Project description:Age-related hearing loss is a progressive sensorineural hearing loss that occurs as people get older. Degeneration of the organ of Corti and atrophy of the lateral wall of the cochlear duct (or scala media) in the inner ear are the two primary causes. MicroRNAs (miRNAs), a class of short non-coding RNAs that regulate the expression of mRNA/protein targets, are important regulators of cellular senescence and aging. We examined the change of miRNA gene expression profiles in the lateral wall of the cochlear duct in two mouse strains during aging
Project description:In order to elucidate molecular mechanisms of noise-induced hearing loss and dexamethasone therapy in the cochlea (inner ear), transcriptome of cochlear samples was analyzed after induction of hearing loss by exposure to intense noise in mice. Dexamethasone was intraperitoneally injected immediately following the noise trauma. Cochlear transcriptome was analyzed at 12h and 24h following the noise trauma and dexamethasone administration.
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: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.
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.
Project description:Alternative splicing contributes to gene expression dynamics in many tissues, yet its role in auditory development remains unclear. We performed whole exome sequencing in individuals with sensorineural hearing loss (SNHL) and identified pathogenic mutations in Epithelial Splicing Regulatory Protein 1 (ESRP1). Patient derived induced pluripotent stem cells showed alternative splicing defects consistent with impaired ESRP1 function. To determine how mutations in ESRP1 cause hearing loss we evaluated Esrp1-/- mouse embryos and uncovered alterations in cochlear morphogenesis, auditory hair cell differentiation and cell fate specification. Transcriptome analysis revealed impaired expression and splicing of genes with essential roles in inner ear development and auditory function. In particular, aberrant splicing of Fgfr2 blocked stria vascularis formation due to erroneous ligand usage, which was corrected by reducing Fgf9 gene dosage. These findings implicate mutations in ESRP1 as a novel cause of SNHL and demonstrate the complex interplay between alternative splicing, inner ear development, and auditory function.
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: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