Mechanisms of hypersensitivity to sound-induced cochlear damage

对声音引起的耳蜗损伤过敏的机制

• 批准号: 9764613
• 负责人: Maria Eulalia Rubio
• 金额: $ 60.32万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-03-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9764613
• 关键词: AMPA Receptors; Acoustics; Address; Age-Months; Aging; Androgens; Attention; Biochemical; Biological Factors; Ca(2+)-Transporting ATPase; Castration; Cochlea; Cochlear Nerve; Complex; Confocal Microscopy; Data; Endoplasmic Reticulum; Environment; Estradiol; Estrogen Receptors; Estrogens; Exhibits; Female; Fiber; Frequencies; Glutamate Receptor; Glutamates; Gonadal Hormones; Gonadal Steroid Hormones; Hearing; Hormones; Hour; Human; Hypersensitivity; Immunohistochemistry; Inner Hair Cells; Ischemia; Knock-out; Knockout Mice; Labyrinth; Lead; Link; Measures; Mediating; Molecular; Mus; Neurons; Noise; Ovarian; Ovarian hormone; Pathogenesis; Phosphorylation; Positioning Attribute; Process; Publishing; Pump; Quantitative Reverse Transcriptase PCR; Role; Sensory; Sex Differences; Signal Transduction; Structure; Surface; Swelling; Synapses; Synaptic Transmission; System; Testing; Western Blotting; auditory pathway; base; childhood hearing loss; excitotoxicity; hearing impairment; male; mutant; nerve supply; neurotoxicity; postsynaptic; protective effect; receptor; receptor function; ribbon synapse; sexual dimorphism; sound; spiral ganglion; trafficking; transmission process

Project Summary All information about the acoustic environment is carried from the inner ear to the CNS by the afferent fibers of the cochlear nerve. Rapidly gating AMPA glutamate receptors (AMPAR; GluA2, GluA3 and GluA4 subunits) mediate synaptic transmission at the mature synapse between the inner hair cells (IHC) and the afferent fibers of the cochlear nerve (IHC synapse). However, the contribution of each type of AMPAR subunit to overall glutamatergic receptor function and afferent transmission/sensitivity in the cochlea is poorly understood. Understanding this process is important because glutamate excitotoxicity through AMPAR has been implicated in the pathogenesis of hearing loss caused by noise, ischemia and aging. Sex differences in the vulnerability to hearing loss occur in humans. We therefore began investigating the contribution of AMPAR subunits to transmission at the IHC synapse and whether there are sex-specific differences in AMPAR subunits that contribute to sound-induced cochlear damage and hearing loss. Based on functional and ultrastructural preliminary data, we now hypothesize that “GluA3 AMPAR subunits have a critical role in the sexually dimorphic vulnerability to hearing loss”. To define mechanistically how GluA3 contributes to the structural and molecular components of IHC synapses and to sex differences that underlie the hypersensitivity to sound- induced cochlear damage, we will use a powerful combination of functional (ABRs, DPOAEs), immunocytochemical (confocal microscopy), biochemical, qRT-PCR, and ultrastructural approaches to test the following hypotheses. In Aim 1, we will determine whether GluA3 promotes the abundance of GluA2 at IHC synapses. In Aim 2, we will determine whether GluA3 at IHC synapses protects mice from sound-induced cochlear damage. Aim 3, based on published data and our preliminary findings, we propose the hypothesis that in the absence of GluA3, ovarian hormones facilitate the hypersensitivity to sound-induced cochlear damage, while androgens have protective effects. These proposed studies are the first to address the important question of how changes in AMPAR subunit composition lead to sex differences in hearing loss.

项目总结