The Role of Eya and its Interacting Gene Six in Inner Ear Development

描述（由申请人提供）：此竞争性修订提案要求提供资金，以支持已批准的母基金范围之外的新研究目标。最初的资助重点是功能丧失研究，以确定Eya和Six基因在早期耳基板诱导和内耳形态发生中的作用，并了解鳃-耳-肾（BOR）综合征中发生的内耳缺陷的发育和分子发病机制。本修订申请建议使用功能获得方法来定义Eya 1在调节毛细胞分化程序中的作用，这在母基金中没有提出。在哺乳动物的听觉系统中，感觉毛细胞的退化是听力损失的最常见原因，影响全球约10%的人口。恢复正常听力的一种潜在方法是使用干细胞/祖细胞，因为它们具有内在的再生能力。然而，目前尚不清楚耳蜗中是否存在能够再生毛细胞的干细胞/祖细胞。听觉感觉毛细胞来源于耳蜗上皮内的前感觉域中约E13.5-14.5的祖细胞。最近的研究表明，Sox 2是所需的感觉细胞谱系的规范，而Atoh 1已被证明是毛细胞发育的关键调节器，但不是指定前感觉祖细胞所需的。然而，到目前为止，感觉细胞谱系是如何被指定的，以及毛细胞的命运是如何决定的，仍然知之甚少。此外，Atoh 1表达如何被激活以及调节毛细胞分化程序的分子遗传途径基本上是未知的。我们最近的数据表明，Eya 1可能与Sox 2相互作用，不仅指定感觉祖细胞，但也可能通过激活Atoh 1的表达来调节毛细胞的承诺。这个竞争性修订应用程序的目标是研究感觉祖细胞的内在程序，重点是进化上保守的Eya 1-Six 1转录复合物，这是内耳正常感觉器官形成的关键，通过功能获得方法。因此，本次修订申请结合母基金中提出的功能丧失研究将大大加强我们对感觉毛细胞分化过程中Eya 1-Six 1转录复合体的分析，并提供对Eya 1-Six 1如何调节毛细胞分化程序的更深入理解，以及对人类BOR患者听力损失基础的新见解。拟议的修订申请不仅将通过雇用一名全职博士后和一名全职研究技术人员来完成新的研究来刺激经济，而且还将产生新的资源，这将对毛细胞发育，再生和维护领域做出重大贡献。 公共卫生相关性：该修订申请提出研究感觉祖细胞的内在程序，重点是进化上保守的Six 1-Eya 1转录复合物，这对内耳正常感觉器官的形成和人类鳃-耳-肾综合征（BOR）的发病机制至关重要。识别基因和蛋白质并了解它们在感觉细胞发育中的作用和功能，最终可能导致内耳毛细胞的预防或再生。

DESCRIPTION (provided by applicant): This Competitive Revision proposal requests funding to support new research aims that are outside of the scope of the approved parent grant. The original grant focuses on loss-o-function studies to define the roles of Eya and Six genes in early otic placode induction and inner ear morphogenesis and understand the developmental and molecular pathogenesis of inner ear defects that occur in the Branchio-Oto-Renal (BOR) syndrome. This revision application proposes to use gain-of-function approaches to define the role of Eya1 in regulating hair cell differentiation program, which is not proposed in the parent grant. In the mammalian auditory system, degeneration of the sensory hair cells is the most common cause of hearing loss affecting approximately 10% of the worldwide population. A potential approach to restore normal hearing is to use stem/progenitor cells because of their intrinsic capacity for regeneration. However, it is currently unclear whether there are stem/progenitor cells capable of regenerating hair cells present in the cochlea. The auditory sensory hair cells are derived from progenitor cells specified in the prosensory domain within the cochlea epithelium at ~E13.5-14.5. Recent studies have shown that Sox2 is required for the specification of sensory cell lineage, while Atoh1 has been shown to be a key regulator for hair cell development but is not required for specifying prosensory progenitors. To date, however, how exactly the sensory cell lineage is specified and how the hair cell fate is determined are still poorly understood. Furthermore, how Atoh1 expression is activated and the molecular genetic pathways regulating hair cell differentiation program are essentially unknown. Our recent data suggest that Eya1 may interact with Sox2 to not only specify sensory progenitors but also regulate hair cell commitment possibly by activating Atoh1 expression. The goal of this Competitive Revision application is to investigate the intrinsic programs of sensory progenitors, focusing on the evolutionarily conserved Eya1-Six1 transcription complex, which is critical for normal sensory organ formation in the inner ear, via gain-of-function approaches. Thus, this revision application in combination with the loss of function studies proposed in the parent grant will greatly strengthen our analysis of Eya1-Six1 transcription complex during sensory hair cell differentiation and provide a deeper understanding of how Eya1-Six1 acts to regulate hair cell differentiation program and new insights into the basis for hearing loss that occurs in human BOR patients. The proposed revision application will not only stimulate the economy by enabling hiring one full-time post-doc and one full-time research technician to accomplish the new studies but also generate novel resources, which will make significant contribution to the field of hair cell development, regeneration and maintenance. PUBLIC HEALTH RELEVANCE: This revision application proposes to investigate the intrinsic programs of sensory progenitors, focusing on the evolutionarily conserved Six1-Eya1 transcription complex, which is critical for normal sensory organ formation in the inner ear and pathogenesis of human Branchio-Oto-Renal syndrome (BOR). Identifying genes and proteins and understanding their roles and functions in the development of sensory cells may eventually lead to prevention or regeneration of inner ear hair cells.