Notch signaling pathways in auditory support cell differentiation and maintenance

听觉支持细胞分化和维持中的Notch信号通路

基本信息

批准号：
8620548
负责人：
ANGELIKA DOETZLHOFER
金额：
$ 41万
依托单位：
JOHNS HOPKINS UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-03-01 至 2016-02-29
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8620548
关键词：
Ablation Address Adopted Adult Aminoglycosides Auditory Birds Cell Communication Cell Differentiation process Cell Lineage Cell Maintenance Cell division Cells Cochlea Cues Data Development Diuretics Epithelial Cells Future Gene Expression Genetic Recombination Global Change Goals Hair Cells Health Human In Situ Hybridization Injection of therapeutic agent Knowledge Label Lead Light Maintenance Mammals Mediating Molecular Mus Mutant Strains Mice Natural regeneration Neuraxis Neuroglia Notch Signaling Pathway Null Lymphocytes Organ Organ of Corti Pathway interactions Peripheral Phenotype Play Replacement Therapy Reporter Role Sensory Sensory Hair Signal Pathway Signal Transduction Staining method Stains Supporting Cell Tamoxifen Testing Time Vertebrates Work base cell injury cell type deafness equilibration disorder hair cell regeneration high throughput analysis improved inhibitor/antagonist insight notch protein novel prevent progenitor programs public health relevance receptor research study response secretase

项目摘要

DESCRIPTION (provided by applicant): In humans and other mammalian species, damage to mechano-sensory hair cells is irreversible, leading to deafness and balance disorders. Remarkably, non-mammalian vertebrates regenerate lost hair cells. In birds, supporting cells have been shown to replace lost hair cells by mechanisms involving either cell division or direct trans-differentiation. In the mammalian auditory sensory organ, supporting cells do not regenerate lost hair cells. Strikingly, our findings suggest that mammalian supporting cells retain the intrinsic ability to function as hair cell progenitors, but their plasticity to regenerate hair cells is actively suppressed by external inhibitory cues. Our long-term goal is to utilize the latent plasticity of supporting cells to develop supporting cell based hair cell replacement strategies. To attain this goal, it is vital to improve our knowledge of the molecular programs active in developing and in mature supporting cells. We reason that to "reprogram" and induce de- differentiation of supporting cells and consequently trans-differentiation of supporting cells into hair cells, we first have to understand the signals that control differentiation and maintenance in the supporting cell lineage. The goal of this proposal is to determine if the Notch signaling pathway, an evolutionary ancient and highly conserved cell-to-cell communication mechanism, functions in supporting cell differentiation and cell maintenance. In Specific Aim 1 of our proposal, we will test if Notch signaling plays an instructive role in supporting cell differentiation. We will test if induction of an activated form of the Notch1 receptor is sufficient to induce supporting cell fate and whether inhibition of Notch signaling with 3-secretase inhibitors effects the onset and progression of supporting cell differentiation. In Specific Aim 2 of our proposal, we will ablate Rbpj, a core component of the canonical Notch signaling pathway, in supporting cells to address if Notch signaling is required for supporting cell maintenance in the intact and hair cell damaged cochlea. To do so we will employ Rbpj conditional mouse mutants in combination with tamoxifen inducible CreERT lines. We anticipate that this analysis will provide valuable insight into the molecular mechanisms that drive supporting cell differentiation and elucidate the function of Notch signaling in supporting cell maintenance in the adult cochlea. In parallel, we will address a longstanding question-"does persistence of Notch signaling in the hair cell damaged cochlea underlie the lack of hair cell regeneration in mammals?" Addressing this question is relevant to human health as inhibiting Notch signaling using 3-secretase inhibitors in mature cochlea could provide a means for restoring a latent capacity to regenerate hair cells.

描述（由申请人提供）：在人类和其他哺乳动物物种中，机械感觉毛细胞的损伤是不可逆的，导致耳聋和平衡障碍。值得注意的是，非哺乳动物脊椎动物能够再生丢失的毛细胞。在鸟类中，支持细胞已被证明可以通过涉及细胞分裂或直接转分化的机制来替代丢失的毛细胞。在哺乳动物的听觉感觉器官中，支持细胞不会再生丢失的毛细胞。引人注目的是，我们的研究结果表明，哺乳动物支持细胞保留了作为毛细胞祖细胞的内在能力，但它们再生毛细胞的可塑性受到外部抑制信号的积极抑制。我们的长期目标是利用支持细胞的潜在可塑性来开发基于支持细胞的毛细胞替代策略。为了实现这一目标，提高我们对发育和成熟支持细胞中活跃的分子程序的了解至关重要。我们推断，要“重新编程”并诱导支持细胞去分化，从而将支持细胞转分化为毛细胞，我们首先必须了解控制支持细胞谱系分化和维持的信号。该提案的目的是确定Notch信号通路（一种进化上古老且高度保守的细胞间通讯机制）是否在支持细胞分化和细胞维持中发挥作用。在我们提案的具体目标 1 中，我们将测试 Notch 信号传导是否在支持细胞分化中发挥指导作用。我们将测试Notch1受体激活形式的诱导是否足以诱导支持细胞命运，以及用3-分泌酶抑制剂抑制Notch信号传导是否影响支持细胞分化的开始和进展。在我们提案的具体目标 2 中，我们将消除 Rbpj（典型 Notch 信号通路的核心组成部分），以解决支持细胞是否需要 Notch 信号来支持完整和毛细胞受损耳蜗的细胞维持。为此，我们将采用 Rbpj 条件小鼠突变体与他莫昔芬诱导型 CreERT 系组合。我们预计该分析将为驱动支持细胞分化的分子机制提供有价值的见解，并阐明 Notch 信号传导在支持成人耳蜗细胞维持中的功能。与此同时，我们将解决一个长期存在的问题——“受损的毛细胞耳蜗中Notch信号的持续存在是否是哺乳动物毛细胞再生缺乏的基础？”解决这个问题与人类健康相关，因为在成熟耳蜗中使用 3-分泌酶抑制剂抑制 Notch 信号传导可以提供一种恢复毛细胞再生潜在能力的方法。