Defining ATOH1 function and regulation in avian supporting cells

描述（由申请人提供）：在美国，有3100万人有听力损失，这通常是由于内耳毛细胞的损失，而内耳毛细胞是正常听力所必需的。人类的听力损失是永久性的，因为毛细胞无法被替换。然而，鸟类的毛细胞很容易再生，从而恢复听力功能。为了开发毛细胞再生作为听力损失的治疗方法，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，并且在发育和成熟的内耳中，Atoh1足以迫使异位毛细胞分化，因此许多先前的研究都集中在Atoh1（一种基本的螺旋-环-螺旋转录因子）在控制毛细胞生成中的作用。因此，Atoh1是促进毛细胞再生的极好候选物质。然而，关于(1)Atoh1在非哺乳动物再生过程中的具体功能，或(2)在静止和再生过程中如何控制Atoh1的活性，我们知之甚少。因此，在Atoh1被证实为人类毛细胞治疗的靶标之前，还需要进行更多的研究。本研究验证了以下相关假设：(1)bmp在正常情况下可拮抗Atoh1活性，使支持细胞保持静止状态，同时降低毛细胞损伤后的分化；(2)分化抑制剂（ID）转录因子在调控Atoh1的支持作用上与Atoh1相反

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.