Avian Hair Cell Regeneration: Molecular Regulation

禽毛细胞再生：分子调控

• 批准号: 7790687
• 负责人: Jennifer S. Stone
• 金额: $ 32.39万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-04-01 至 2012-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7790687
• 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）：鸟类是唯一已知在成熟时再生内耳感觉毛细胞（HC）的温血脊椎动物。最近的研究表明，鸟类利用两种机制来产生新的HC：祖细胞（非感觉支持细胞（SC））的重新细胞分裂，以及SC直接转分化为HC，而不干预有丝分裂。禽HC再生的研究提供了一个重要的机会，阐明这些SC响应HC损失的细胞和分子机制。这些研究是指导分析哺乳动物HC-上皮中SC行为的关键前奏，以确定为什么HC再生在哺乳动物中没有完成。我们将集中在两个分子的作用，Atoh 1和Notch，这是哺乳动物HC发展的关键。目的1将解决信号调节SC决定直接转分化后，HC损伤成熟鸡BPs通过测试的假设，Notch激活拮抗转分化，而Atoh 1激活促进it. We将检查受损的BPs，以确定是否时空表达模式的基因在Notch通路支持提出的作用Notch。我们将激活或抑制Notch，其配体和其效应子，并确定直接转分化是否会发生改变。我们还将测试的假设Atoh 1功能是必要的和足够的直接转分化。在目标2中，我们将通过检验Atoh 1和Notch都抑制SC分裂的假设，来解决调节SC在禽BP中HC损伤后分裂决定的信号。我们将确定Atoh 1的过度表达是否会导致SC分裂的细胞自主抑制，以及Atoh 1的抑制是否会促进分裂。我们将确定Notch通路中的哪些基因在分裂的SC和它们周围的细胞中被改变。我们将确定Notch功能的操作是否显著改变SC分裂的速率。在目标3中，我们将评估Atoh 1表达和直接转分化在HC损伤后成年小鼠椭圆囊SC中自发发生的程度。我们将研究如何在Notch途径的基因表达改变成年小鼠椭圆囊后HC损失。我们还将测试的假设，抑制Notch信号在成年小鼠椭圆囊促进直接转分化和SC分裂。