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: 10242086
• 负责人: Courtney C. Kellogg
• 金额: $ 4.6万
• 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/10242086
• 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; Regenerative capacity; Regenerative research; Research Personnel; Research Project Grants; Role; Sensory; Sensory Hair; Signal Transduction; Snails; Structure; Supporting Cell; Testing; Time; Training; Work; cell injury; cell type; clinical application; conditional knockout; deafness; experience; hearing impairment; inner ear development; loss of function; mutant; notch protein; organ growth; overexpression; progenitor; regenerative; regenerative approach; repaired; stem cells; 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.

摘要 听力损失是一个常见的健康问题，影响着全球数百万人。大多数听力损失是由于 内耳中的耳蜗感觉区Corti器官的损害。不幸的是，一旦损坏 发生于Corti器官内的关键细胞类型，包括毛细胞(HC)、支持细胞(SC)和神经元， 这些细胞不能修复或再生。了解基因和分子因素参与的 这些关键细胞类型的发展将有助于未来对这些细胞的再生和修复的研究 细胞。因此，有必要更好地了解内耳的分子机制。 发展。研究表明，许多基因，如Notch配体Jag1和转录 Sox2因子对耳朵的感觉形成至关重要。然而，目前还不清楚这些基因是如何促进 感觉队形。这项建议的目标是研究这些基因在耳蜗术中的作用(S 通过两个具体目标实现发展。在第一个目标中，我将调查是否有多个角色 JAG1在耳蜗发育过程中的作用。我的初步数据表明，通过在不同的时间敲除JAG1 在发育过程中，观察到不同的表型。早期，JAG1在整个感觉中都有表达 地区，并已牵连在感官规格。先前对Jag1条件性基因敲除的研究表明 感觉细胞形成的丧失，支持JAG1在感觉前体发育中的作用。之前的数据也 表明Notch可能参与了发育后期的边界形成。因此，我将剖析 Jag1在不同发育阶段条件性敲除Jag1在胚胎耳蜗发育中的作用(S) 发育时间点决定了JAG1是感觉发育所必需的时间和方式。在第二个 作为目标1的一部分，我将确定JAG1是否足以扩大感觉前体细胞的池。上一首 研究表明，早期异位Notch激活，导致异位感觉区的形成， 说明凹槽足以驱动感觉形成。为了测试JAG1是否是调节这一过程的配体 角色，我将在耳廓发育的早期过度表达Jag1，并确定这是否可以创建扩展的或 异位感觉区。在目标2中，我将研究JAG1和SOX2之间的关系。以前的数据 显示Notch激活上调SOX2，而敲除Jag1下调SOX2，表明 JAG1是SOX2的上游分子调控因子。因此，我将调查JAG1是否通过SOX2起作用 建立感觉前体细胞的形成。为了实现这一点，我将在JAG1中过度表达Sox2 以确定是否可以挽救感觉信息。这项提案的结果将提供更好的 了解耳蜗发育的分子机制，这可能是 了解可能的再生能力或方法。