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

描述（由申请人提供）：本竞争性修订提案请求资助，以支持已批准的父母资助范围之外的新研究目标。最初的资助侧重于功能丧失研究，以确定Eya和6个基因在早期耳位诱导和内耳形态发生中的作用，并了解Branchio-Oto-Renal （BOR）综合征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的方法来确定Eya1在调节毛细胞分化程序中的作用，这在亲本拨款中没有提出。在哺乳动物听觉系统中，感觉毛细胞的退化是导致听力损失的最常见原因，影响了全球约10%的人口。使用干细胞/祖细胞是恢复正常听力的一种潜在方法，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~ e13.5 ~ 14.5耳蜗上皮内前感觉区指定的祖细胞。最近的研究表明，Sox2是指定感觉细胞谱系所必需的，而Atoh1已被证明是毛细胞发育的关键调节因子，但不是指定前感觉祖细胞所必需的。然而，到目前为止，感觉细胞谱系是如何确定的，毛细胞的命运是如何决定的，人们仍然知之甚少。此外，Atoh1的表达是如何被激活的以及调控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，Eya1可能与Sox2相互作用，不仅指定感觉祖细胞，而且可能通过激活Atoh1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通过功能获得的方法研究感觉祖细胞的内在程序，重点关注进化上保守的Eya1-Six1转录复合物，这对内耳正常感觉器官的形成至关重要。因此，本次修订申请与亲本资助中提出的功能丧失研究相结合，将大大加强我们对感觉毛细胞分化过程中Eya1-Six1转录复合物的分析，更深入地了解Eya1-Six1如何调节毛细胞分化程序，并对人类BOR患者发生听力损失的基础有新的认识。修订后的申请，不但可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，从而刺激经济，而且可产生新的资源，对毛细胞的发育、再生和维护领域作出重大贡献。

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.