Avian Hair Cell Regeneration: Molecular Regulation

禽毛细胞再生：分子调控

• 批准号: 7903541
• 负责人: Jennifer S. Stone
• 金额: $ 16.36万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-14 至 2011-10-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7903541
• 关键词: Address; Adult; Area; Basilar Papilla; Birds; Blood; Calculi; Cell Cycle; Cell division; Cells; Chickens; Development; Disease; Epithelium; Gene Expression; Genes; Goals; Hair Cells; Hearing; Human; In Situ Hybridization; In Vitro; Individual; Labyrinth; Ligands; Mammals; Methods; Mitosis; Mitotic; Molecular; Mus; Natural regeneration; Pathway interactions; Pattern; Regulation; Relative (related person); Research; Research Personnel; Rodent; Role; Sensory; Sensory Hair; Signal Pathway; Signal Transduction; Stem cells; Supporting Cell; Testing; Utricle structure; Vertebrates; cell behavior; cell injury; equilibration disorder; hair cell regeneration; in vivo; knock-down; notch protein; overexpression; prevent; programs; receptor; regenerative; research study; response; stem; transcription factor; transdifferentiation

DESCRIPTION (provided by applicant): Birds are the only warm-blooded vertebrates known to regenerate sensory hair cells (HCs) of the inner ear in maturity. Recent studies have demonstrated that birds utilize two mechanisms to generate new HCs: renewed cell division of progenitor cells, the non-sensory supporting cells (SCs), and direct transdifferentiation of SCs into HCs, without intervening mitosis. Studies of avian HC regeneration offer an important opportunity to elucidate cellular and molecular mechanisms governing these SC responses to HC loss. Such studies are critical preludes for directing analyses of SC behavior in mammalian HC-epithelia toward determining why HC regeneration is not completed in mammals. We will focus on the role of two molecules, Atoh1 and Notch, which are critical for mammalian HC development. Aim 1 will address signals regulating the SC decision to directly transdifferentiate after HC damage in mature chicken BPs by testing the hypotheses that Notch activation antagonizes transdifferentiation while Atoh1 activation promotes it. We will examine damaged BPs to determine if temporospatial expression patterns of genes in the Notch pathway support the proposed role for Notch. We will activate or inhibit Notch, its ligands, and its effectors and determine if direct transdifferentiation becomes altered in response. We will also test the hypothesis that Atoh1 function is necessary and sufficient for direct transdifferentiation. In Aim 2, we will address signals regulating the SC decision to divide after HC damage in avian BPs by testing the hypothesis that Atoh1 and Notch both inhibit SC division. We will determine if overexpression of Atoh1 leads to cell-autonomous inhibition of SC division and if inhibition of Atoh1 promotes division. We will determine which genes in the Notch pathway are altered in dividing SCs and in cells surrounding them. We will determine if manipulation of Notch function significantly alters rates of SC division. In Aim 3, we will assess the extent to which Atoh1 expression and direct transdifferentiation occur spontaneously in SCs of the adult mouse utricle after HC damage. We will examine how expression of genes in the Notch pathway is altered in adult mouse utricles after HC loss. We will also test the hypotheses that inhibition of Notch signaling in adult mouse utricles promotes direct transdifferentiation and SC division.

描述（由申请人提供）：鸟类是已知唯一成熟内耳感觉毛细胞（HCs）再生的温血脊椎动物。最近的研究表明，鸟类利用两种机制产生新的hcc：祖细胞、非感觉支持细胞（SCs）的更新细胞分裂，以及SCs直接转分化为hcc，而不干预有丝分裂。禽类HC再生的研究为阐明这些SC对HC损失的反应的细胞和分子机制提供了重要的机会。这些研究是指导分析哺乳动物HC-上皮中SC行为以确定为什么HC在哺乳动物中不能完成再生的关键前驱。我们将重点关注Atoh1和Notch这两个对哺乳动物HC发育至关重要的分子的作用。目的1将通过验证Notch激活拮抗转分化而Atoh1激活促进转分化的假设，探讨成熟鸡bp中HC损伤后SC直接转分化决定的调节信号。我们将检查受损的bp，以确定Notch通路中基因的时空表达模式是否支持Notch的拟议作用。我们将激活或抑制Notch、其配体及其效应物，并确定直接转分化是否在响应中发生改变。我们还将检验Atoh1函数对于直接转分化是必要和充分的假设。在Aim 2中，我们将通过测试Atoh1和Notch都抑制SC分裂的假设来解决禽类bp中HC损伤后SC分裂决定的调节信号。我们将确定过表达Atoh1是否会导致细胞自主抑制SC分裂，而抑制Atoh1是否会促进SC分裂。我们将确定Notch通路中的哪些基因在分化sc及其周围细胞中发生改变。我们将确定Notch功能的操作是否显著改变SC分裂率。在Aim 3中，我们将评估成年小鼠HC损伤后胞室SCs中Atoh1的表达和直接转分化自发发生的程度。我们将研究Notch通路中基因的表达在HC缺失后如何在成年小鼠胞囊中发生改变。我们还将测试成年小鼠胞体中Notch信号的抑制促进直接转分化和SC分裂的假设。