The role of transcription factors and chromatin remodeling proteins in spiral ganglion neuron regeneration

 描述（由申请人提供）：螺旋神经节神经元（SGN）缺失引起的听觉神经病导致听力损失。标准补救措施，如使用助听器和人工耳蜗植入物在SGN丢失后无效。许多日常耳毒性损伤，如响亮的声音，导致突触接触的急性丧失，听觉神经纤维的变性和SGN的长期丧失。鉴于不断增加的老龄化人口暴露于便携式音乐播放器的巨大声音，SGN的退化将成为一个主要的健康问题。干细胞替代疗法有很大的希望重新填充丢失的SGN和恢复听力功能。为了正确使用干细胞治疗听力损失，识别可以在干细胞中重现SGN发育的基因将加速替代疗法的努力。使用永生化耳祖细胞（iMOP）细胞系，我们确定了新的候选转录因子和染色质重塑蛋白，在SGN的发展和再生是重要的。Chd 4是一种染色质重塑蛋白，是核小体重塑和脱乙酰酶（NuRD）复合物的一部分。我们建议，Chd 4是必不可少的神经元规格，轴突的指导和突触在SGN的发展。我们将使用iMOP衍生的神经元和内耳Chd4敲除动物来测试Chd4在指定神经元命运和神经突延伸中的作用。使用iMOP衍生的神经元和去传入耳蜗外植体共培养系统，我们将研究Chd4如何促进轴突引导毛细胞靶点。最后，我们将产生一个他莫昔芬诱导的Chd4基因敲除动物，以确定在SGN成熟过程中突触发生的缺陷。

 DESCRIPTION (provided by applicant): Auditory neuropathy caused by the loss of spiral ganglion neurons (SGN) loss results in hearing loss. Standard remediation, such as the use of hearing aids and cochlear implants are ineffective after the loss of SGNs. Many daily ototoxic insults such as loud sounds result in acute loss of synaptic contacts, degeneration of the auditory nerve fibers and loss of SGN over an extended period of time. Given an ever-increasing aging population that is exposed to loud sounds from portable music players, degeneration of SGNs will become a major health concern. Stem cell replacement therapies hold great promise to repopulate lost SGNs and restore hearing function. In order to properly use stem cells to treat hearing loss, identifying genes that can recapitulate SGN development in stem cells will accelerate efforts for replacement therapies. Using an immortalized otic progenitor (iMOP) cell line, we identified novel candidate transcription factors and chromatin remodeling proteins that are important in SGN development and regeneration. One of the candidates is Chd4, a chromatin remodeling protein that is part of the nucleosome remodeling and deacetylase (NuRD) complex. We propose that Chd4 is essential for neuronal specification, axon guidance and synaptogenesis during SGN development. We will test the role of Chd4 in specifying neuronal fate and neurite extension using iMOP-derived neurons and an inner ear Chd4 knockout animal. Using an iMOP-derived neuron and deafferented cochlear explant co-culture system, we will study how Chd4 promotes axon guidance to the hair cell targets. Finally, we will generate a tamoxifen inducible Chd4 knockout animal to determine defects in synaptogenesis during SGN maturation.