Multiple roles of the Notch Ligand, Jagged1, in Sensory Development of the Cochlea

Notch 配体 Jagged1 在耳蜗感觉发育中的多重作用

• 批准号: 9911580
• 负责人: Courtney C. Kellogg
• 金额: $ 4.5万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-01 至 2022-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9911580
• 关键词: Address; Affect; Alleles; Cells; Cochlea; Cognitive; Data; Defect; Development; Ear; Embryo; Embryonic Development; Future; Genes; Genetic; Goals; Hair Cells; Health; Hearing; Inner Hair Cells; Knock-out; Knockout Mice; Labyrinth; Ligands; Mediating; Medical; Molecular; Morphology; Natural regeneration; Neurons; Notch Signaling Pathway; Organ of Corti; Outer Hair Cells; Pathology; Pattern; Phenotype; Play; Research Personnel; Research Project Grants; Role; Sensory; Sensory Hair; Signal Transduction; Snails; Stem cells; Structure; Supporting Cell; Testing; Time; Training; Work; cell injury; cell type; clinical application; deafness; experience; hearing impairment; inner ear development; loss of function; mutant; notch protein; organ growth; overexpression; progenitor; regenerative; repaired; transcription factor

Abstract Hearing loss is a common health issue that affects millions of people worldwide. Most hearing loss is the result of damage to the organ of Corti, the sensory region of the cochlea in the inner ear. Unfortunately, once damage occurs to critical cell types within the organ of Corti, including hair cells (HC), supporting cells (SC), and neurons, these cells cannot be repaired or regenerated. Understanding the genetic and molecular factors involved in the development of these critical cell types will aid future studies on deriving the regeneration and repair of these cells. Thus, it is necessary to gain a better understanding of the molecular mechanisms involved in inner ear development. Studies have shown that a number of genes, such as the Notch ligand Jag1 and transcription factor Sox2, are critical for sensory formation in the ear. However, it is unclear how these genes act to promote sensory formation. The goal of this proposal is to investigate the role(s) of these genes during cochlear development through two specific aims. In the first aim, I will investigate whether there are multiple roles for JAG1 during cochlear development. My preliminary data suggest that, by knocking JAG1 out at different time points during development, different phenotypes are observed. Early, JAG1 is expressed throughout the sensory region and has been implicated in sensory specification. Previous studies of Jag1 conditional knockouts show loss of sensory cell formation, supporting JAG1 role in sensory progenitor development. Previous data also indicates that Notch may be involved in boundary formation later in development. Thus, I will dissect the functional role(s) of Jag1 during embryonic cochlear development by conditionally knocking out Jag1 at different developmental time points to determine when and how JAG1 is required for sensory development. In the second part of Aim 1, I will determine whether JAG1 is sufficient to expand the pool of sensory progenitors. Previous studies have shown that early ectopic Notch activation, leads to the formation of ectopic sensory regions, indicating Notch is sufficient to drive sensory formation. To test whether JAG1 is the ligand that mediates this role, I will overexpress Jag1 during early otic development and determine whether this can create expanded or ectopic sensory regions. In Aim 2, I will examine the relationship between JAG1 and SOX2. Previous data showed that Notch activation upregulates SOX2, whereas knocking out Jag1 downregulates SOX2, indicating that JAG1 is an upstream molecular regulator of SOX2. Thus, I will investigate whether JAG1 acts via SOX2 to establish sensory progenitor cell formation. To accomplish this, I will overexpress Sox2 in JAG1 loss-of-function embryos to determine if sensory information can be rescued. Results from this proposal will provide a better understanding of the molecular mechanisms underlying cochlear development, which may be key to understanding possible regenerative capacities or approaches.

抽象的 听力损失是一个常见的健康问题，会影响全球数百万的人。大多数听力损失是结果 对Corti器官的损害，Corti的内耳中耳蜗的感觉区域。不幸的是，一次损坏 发生在Corti器官内的关键细胞类型中，包括毛细胞（HC），支持细胞（SC）和神经元， 这些细胞无法修复或再生。了解涉及的遗传和分子因素 这些关键细胞类型的开发将有助于未来的研究得出这些关键细胞的再生和修复 细胞。因此，有必要更好地了解内耳中涉及的分子机制 发展。研究表明，许多基因，例如Notch配体JAG1和转录 因子SOX2对于耳朵中的感觉形成至关重要。但是，尚不清楚这些基因如何促进 感觉形成。该提案的目的是研究这些基因在人工耳蜗期间的作用 通过两个具体目标开发。在第一个目标中，我将调查是否有多个角色 人工耳蜗开发期间的JAG1。我的初步数据表明，通过在不同时间将JAG1淘汰 在发育过程中，观察到不同的表型。早期，JAG1在整个感觉中表达 区域已与感觉规范有关。 JAG1条件淘汰的先前研究表明 感觉细胞形成的丧失，支持JAG1在感觉祖细胞发展中的作用。先前的数据也是如此 表明Notch在后来的开发中可能参与边界形成。因此，我将剖析 JAG1在胚胎人工耳蜗发育过程中的功能作用，通过有条件地敲除JAG1在不同的 发育时间点要确定感觉发展何时以及如何需要JAG1。在第二个 AIM 1的一部分，我将确定JAG1是否足以扩大感觉祖细胞的池。以前的 研究表明，早期异位凹入激活导致异位感觉区域的形成， 表明缺口足以驱动感觉形成。测试JAG1是否是介导的配体 角色，我将在早期发育过程中过表达JAG1，并确定这是否可以创造扩展或 异位感觉区域。在AIM 2中，我将研究JAG1和SOX2之间的关系。以前的数据 表明Notch激活上调SOX2，而敲除JAG1的sox2下调，表明 该JAG1是SOX2的上游分子调节剂。因此，我将调查JAG1是否通过SOX2进行作用 建立感觉祖细胞形成。为此，我将在JAG1功能丧失中过表达Sox2 胚胎以确定是否可以拯救感官信息。该提案的结果将提供更好的 了解人工耳蜗的基础机制，这可能是 了解可能的再生能力或方法。