Defining ATOH1 function and regulation in avian supporting cells

描述(申请人提供)：在美国，3100万人患有听力损失，这通常是由于内耳毛细胞的丧失，而毛细胞是正常听力所必需的。人类的听力损失是永久性的，因为毛细胞是不可替代的。然而，鸟类的毛细胞很容易再生，恢复了听力功能。为了开发毛细胞再生作为治疗听力损失的方法，我们必须了解控制非哺乳动物毛细胞再生的因素。由于Atoh1在毛细胞发育过程中是毛细胞分化所必需的，也因为Atoh1在发育和成熟的内耳中足以迫使异位毛细胞分化，所以许多先前的研究都集中在Atoh1在毛细胞生成中的调控作用。因此，Atoh1是促进毛细胞再生的极佳候选者。然而，对于(1)Atoh1‘S在非哺乳动物再生过程中的特定功能，或(2)Atoh1活性在静止和再生过程中是如何控制的，我们知之甚少。因此，在Atoh1被确认为人类水平的毛细胞治疗靶点之前，还需要进行更多的研究。该方案验证了以下相关假设：(1)BMP拮抗Atoh1活性，使支持细胞在正常情况下处于静止状态，同时减少损伤后毛细胞的分化；(2)分化抑制(ID)转录因子对抗Atoh1对支持细胞的控制 在对照组织和毛细胞损伤后的细胞行为；以及(3)BMPs通过增加Atoh1蛋白的降解来对抗毛细胞分化。孵化后的鸡除了器官类型培养、基因错误表达工具和组织学分析外，还将用于检验这些假说。这些实验将使该领域更接近于了解鸡的毛细胞再生是如何调控的，这将为在哺乳动物模型中进行更多知情的、基于假设的实验铺平道路。这一方法将有助于确定最终应用于人类的基因治疗的有力候选者。

DESCRIPTION (provided by applicant): In the United States, 31 million people have hearing loss, which is typically due to the loss of hair cells in the inner ear, which are needed for norma hearing. Hearing loss is permanent in humans, since hair cells cannot be replaced. However, regeneration of hair cells readily occurs in birds, restoring hearing function. To develop hair cel regeneration as a therapy for hearing loss, we must understand the factors controlling hair cell regeneration in non-mammals. Many prior studies have focused on the role of Atoh1, a basic helix-loop-helix transcription factor, in control of hair cell production because Atoh1 is necessar for hair cell differentiation during development, and because Atoh1 is sufficient to force differentiation of ectopic hair cells in the developing and mature inner ear. Therefore, Atoh1 is an excellent candidate for promoting hair cell regeneration. However, very little is known about (1) Atoh1's specific functions during regeneration in non- mammals, or (2) how Atoh1 activity is controlled during quiescence and regeneration. Therefore, additional studies are required before Atoh1 can be validated as a target for hair cell therapy at the human level. This proposal tests the following related hypotheses: (1) BMPs antagonize Atoh1 activity and keep supporting cells quiescent under normal conditions while decreasing hair cell differentiation after damage; (2) inhibitor of differentiation (ID) transcription factors oppose Atoh1 in their control of supporting cell behaviors in control tissue and after hair cell damage; and (3) BMPs act to antagonize hair cell differentiation through increased ATOH1 protein degradation. Post-hatch chickens will be used to test these hypotheses in addition to organotypic cultures, gene misexpression tools, and histological analyses. These experiments will move the field closer to understanding how hair cell regeneration is regulated in chickens, which will pave the way for more informed, hypothesis-based experiments in mammalian models. This approach will be instrumental in identifying strong candidates for gene therapy for eventual application in humans.