Cellular Interactions During Ear Development

耳朵发育过程中的细胞相互作用

• 批准号: 6646478
• 负责人: BERND FRITZSCH
• 金额: $ 33万
• 依托单位: CREIGHTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-01 至 2005-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6646478
• 关键词: afferent nerve; biological signal transduction; brain derived neurotrophic factor; cell cell interaction; developmental genetics; developmental neurobiology; ear hair cell; epithelium; gene expression; genetically modified animals; growth factor receptors; immunocytochemistry; in situ hybridization; innervation; intermolecular interaction; laboratory mouse; labyrinth; neurogenesis; neurogenetics; neurons; neurotrophic factors; polymerase chain reaction; receptor expression

DESCRIPTION (provided by applicant): In this application we want to resolve some of the molecular and cellular interactions that lead to the formation of the two main sensorineuronal cell types of the ear, the hair cell for mechanoelectric transduction and the sensory neurons for conduction of information from the hair cells to the brain. Using morphological (e.g. immunohistochemistry and DiI labeling) and molecular biological approaches (e.g. in situ hybridization, and RTPCR) we will analyze aspects of 1) cell survival, 2) general cell fate determination, and 3) organ specific cell fate determination. In AIM 1 we will scrutinize the role played by both location and amount of neurotrophin expression in patterning inner ear innervation. Inner ear sensory neurons express both trkB and trkC receptors. This unique feature will allow us to analyze in a BDNF null mutant simultaneously carrying a neurotrophin transgene (NT3 tgBDNF) for the first time in vivo how both concentration and distribution of a neurotrophin affect the patterning of normal and aberrant nerve fibers. In AIM 2 we will examine the molecular and cellular interactions of the principle neurogenic bHLH genes expressed in the ear; ngn1, Math1 and NeuroD. We will examine a possible clonal relationship between sensory neurons and hair cells and how the absence of varying combinations of proneuronal bHLH genes affects ear development, in particular the gene expression patterns in supporting cells. In contrast to the brain, this analysis is feasible because only two bHLH genes (Math1, ngn1) determine two neuron-like cells (hair cells, sensory neurons). We will interbreed mutants of ngn1, Math1, and NeuroD to study how ngn1 affects Math1, how ngn1 affects NeuroD, how Math1 affects NeuroD and how double nulls for both ngn1 and Math1 affect formation of the remaining ear. In AIM 3 we will analyze how BF1 and FGF10 affect the formation of organ specific sensory neurons and sensory epithelia absent in these mutants. We will characterize the expression of the bHLH genes, ngn1 and Math1, in null mutants of BF1 and FGF10. Such information can guide future research on regeneration of these cells in patients suffering sensorineuronal hearing loss and other areas of neuroscience less amenable to such investigations.

描述（由申请人提供）：在本应用程序中，我们想解决一些分子和细胞相互作用，从而导致耳朵的两种主感觉神经元细胞类型形成，用于机械电的毛细胞和感官神经元，以传导从毛细胞到大脑的信息。使用形态学（例如免疫组织化学和DII标记）和分子生物学方法（例如原位杂交和RTPCR），我们将分析1）细胞存活的方面，2）一般细胞命运确定，以及3）有机细胞命运的确定。 在AIM 1中，我们将仔细研究神经营养蛋白表达在模式内耳神经支配中所起的作用。内耳感觉神经元同时表达TRKB和TRKC受体。这一独特的功能将使我们能够在携带神经营养蛋白转基因（NT3 TGBDNF）的BDNF无效突变体中进行分析，这是在体内首次在体内首次分析神经营养蛋白的浓度和分布如何影响正常和异常神经纤维的模式。在 AIM 2我们将检查耳朵中表达的原理神经源性BHLH基因的分子和细胞相互作用。 NGN1，MATH1和NEUROD。我们将检查感觉神经元与毛细胞之间可能存在克隆关系，以及额内神经元BHLH基因的不同组合如何影响耳朵发育，特别是支持细胞中的基因表达模式。与大脑相反，该分析是可行的，因为只有两个BHLH基因（Math1，ngn1）决定了两个神经元样细胞（毛细胞，感觉神经元）。我们将在NGN1，MATH1和NEUROD的杂交突变体研究NGN1如何影响Math1，NGN1如何影响Neurod，Math1如何影响NEUROD以及NGN1和MATH1的双重零值会影响其余耳朵的形成。 在AIM 3中，我们将分析BF1和FGF10如何影响这些突变体中没有器官特异性感觉神经元和感觉上皮的形成。我们将表征BF1和FGF10的零突变体中BHLH基因NGN1和MATH1的表达。这些信息可以指导对这些细胞再生的未来研究，这些细胞在患有感官神经元听力损失的患者中，而神经科学的其他领域则不太适合此类研究。