Understanding the mechanism of Sox2 haploinsufficiency on supporting cell to hair cell conversion in the mature mouse cochlea.

摘要 听力损失影响全球数百万人，可由耳毒性药物、娱乐性 或职业性噪音暴露，以及衰老；目前，没有听力损失的治疗方法。近期 进展表明，治疗听力损失的努力可能受益于基因治疗方法。然而， 促进成熟耳蜗感觉毛细胞再生的策略尚未提供可靠的 听力损失的治疗。最初的研究集中在毛细胞诱导转录因子Atoh1，它 在新生儿组织中迅速将邻近的支持细胞转化为毛细胞，但效果有限 在成熟的耳蜗里。最近的证据支持一种多因素方法，该方法涉及对 支持细胞内的毛细胞和支持细胞基因。这种方法仍然是有限的，因为它没有 产生类似正常毛细胞的细胞。先前的证据表明，Sox2的一个等位基因的缺失 导致单倍体不足的表型，在发育过程中产生额外的内毛细胞 在新生小鼠耳蜗处观察到促进再生。这项研究将通过以下方式扩展这些发现 利用基因工程小鼠株系研究SOX2单倍体缺乏的机制 在功能上和基因上都成熟的耳蜗虫。我的初步数据显示SOX2单倍体不足 在表达后促进支持细胞重新编程为未受损耳蜗区的毛细胞 毛细胞转录因子Atoh1、Gfi1和Pou4f3。这项研究的目标1将调查Sox2 单倍体功能不全可以启动支持细胞对这些毛细胞转录因子的反应并再生 失去了毛细胞。这项研究的目标2将探索Sox2单倍体不足促进 通过评估SOX2的直接和间接靶标以及 基因表达谱的整体变化。为此，我将执行RNA、ATAC和Cut&Run-Chip- 对纯化的成熟支持细胞进行测序以评估Sox2单倍体不足的后果。

Abstract Hearing loss affects millions of people worldwide and can result from ototoxic medications, recreational or occupational noise exposure, as well as aging; currently, there is no treatment for hearing loss. Recent advances suggest that efforts to treat hearing loss may benefit from a gene therapy approach. However, strategies to promote the regeneration of sensory hair cells in the mature cochlea have yet to provide a reliable therapy for hearing loss. Research initially focused on the hair cell inducing transcription factor Atoh1, which rapidly converts neighboring supporting cells into hair cells in neonatal tissue but has produced limited results in the mature cochlea. More recent evidence supports a multifactor approach that involves the modulation of both hair cell and supporting cell genes within supporting cells. This approach is still limited, as it does not produce cells which resemble normal hair cells. Previous evidence indicated that the loss of one allele of Sox2 results in a haploinsufficient phenotype that produced extra inner hair cells during development as well as enhancing regeneration observed in the neonatal mouse cochlea. This study will extend these findings by using genetically engineered mouse lines to investigate the mechanism of Sox2 haploinsufficiency in the mature cochlea both functionally and genetically. My preliminary data suggests that Sox2 haploinsufficiency promotes the reprogramming of supporting cells into hair cells in the undamaged cochlea after the expression of the hair cell transcription factors Atoh1, Gfi1, and Pou4f3. Aim 1 of this study will investigate whether Sox2 haploinsufficiency can prime supporting cells to respond to these hair cell transcription factors and regenerate lost hair cells. Aim 2 of this study will explore the mechanism by which Sox2 haploinsufficiency promotes the conversion of supporting cells into hair cells by assessing both direct and indirect targets of Sox2 as well as the overall changes in gene expression profiles. To do this, I will perform RNA, ATAC, and CUT & RUN-ChIP- sequencing on purified mature supporting cells to assess the consequences of Sox2 haploinsufficiency.