Signals Integrating Cellular Dynamics to Sculpt the Inner Ear (A1)

信号整合细胞动力学来塑造内耳 (A1)

• 批准号: 8824915
• 负责人: Suzanne L Mansour
• 金额: $ 45.56万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-04-01 至 2016-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8824915
• 关键词: Ablation; Animal Model; Auditory; Automobile Driving; Behavior; Cell Proliferation; Cell Shape; Cells; Characteristics; Chemicals; Chick Embryo; Data; Development; Diagnosis; Embryo; Epithelial; Epithelium; Event; Experimental Models; FGF10 gene; FGF3 gene; Fibroblast Growth Factor; Foundations; Gene Expression; Genetic; Growth Factor; Hearing problem; Human; Knowledge; Labyrinth; Lateral; Molecular Genetics; Morphogenesis; Mus; Mutation; Organ; Pathway interactions; Pattern; Primordium; Process; Publishing; Research Personnel; Role; SHH gene; Sensory; Shapes; Signal Pathway; Signal Transduction; Squamous Cell; System; Techniques; Testing; Time; Work; cell behavior; cell fate specification; dosage; equilibration disorder; gain of function; hearing impairment; human subject; inhibitor/antagonist; membranous labyrinth; molecular marker; novel; novel strategies; otoconia; prevent; research study; time use

DESCRIPTION (provided by applicant): Misregulation of intercellular signaling disrupts inner ear morphogenesis in human subjects and animal models, leading to hearing and balance disorders. Normal morphogenesis of the inner ear's membranous labyrinth requires temporal integration of regional and cell fate specification with changes in cell behavior. Past work has begun to identify changes in otocyst gene expression downstream of signals, including BMP, FGF and SHH, but much less is known about the cell behaviors driving morphogenesis and how these behaviors are coordinated temporally with progressive restriction of cell fates to generate the mature vestibular and cochlear compartments. Using temporally and spatially controlled loss- and gain-of-function in chick and mouse embryos, we propose to test the general hypothesis that BMP/TGFss, FGF and HH signaling are integrated to regulate otocyst regional and cell fate specification and cell behavior to initiate normal morphogenesis of the vestibular and cochlear compartments of the developing membranous labyrinth. Our preliminary data provide proof-of-principle for our approach. In control chick embryos, we identified a columnar-to-squamous cell shape change in the dorsolateral otocyst epithelium that occurs concomitant with thinning and expansion to form the primordial canal pouch. Spatiotemporally controlled loss- and gain-of-function experiments showed that BMP/SMAD signaling is both necessary and sufficient for this cell shape change. In addition, similar chick misexpression experiments revealed a common intersection point regulating BMP/SHH signaling during early otocyst dorsoventral patterning and morphogenesis. In mouse, we found that otocyst-derived FGF3 and FGF10 signals, in addition to their well-known roles in vestibular morphogenesis, are required to initiate cochlear morphogenesis. However, these epithelial signals are not required for early otocyst regional patterning, which is normal in FGF-deficient otocysts. Therefore, we propose to test the specific hypotheses that 1) temporal integration of BMP/TGFss, FGF and HH signaling controls three key early steps of otocyst morphogenesis: primordial canal outgrowth, subdivision of the primordium into vertical and lateral canal pouches and initial cochlear outgrowth, and 2) that such signaling coordinates otocyst regional and/or cell fate specification with changes in relevant cell behaviors. Our proposal takes advantage of the unique expertise of a team of established investigators using state-of-the-art molecular genetic and embryologic techniques in two animal models with complementary strengths that will illuminate important differences and similarities in mechanisms driving key morphogenetic steps downstream of growth factor signaling. This will advance the field by providing a novel understanding of how signaling pathways are integrated to control initiation of vestibular and cochlear morphogenesis, and how these signals coordinate specification of cell fate and changes in cell behavior to initiate and sculpt a normally functioning membranous labyrinth. Such information provides an essential foundation for understanding and ultimately preventing human hearing loss.

描述(申请人提供)：在人类受试者和动物模型中，细胞间信号的错误调节扰乱了内耳的形态发生，导致听力和平衡障碍。内耳膜迷路的正常形态发生需要区域和细胞命运指定与细胞行为变化的时间整合。过去的工作已经开始识别信号下游的耳囊基因表达的变化，包括BMP，成纤维细胞生长因子和SHH，但对于驱动形态发生的细胞行为，以及这些行为如何与细胞命运的渐进限制相协调以产生成熟的前庭和耳蜗室，我们知之甚少。利用鸡和小鼠胚胎在时间和空间上受控的功能丧失和获得，我们建议检验BMP/TGFss、成纤维细胞生长因子和HH信号整合来调控耳囊局部和细胞命运以及细胞行为的普遍假设，以启动发育中的膜性迷路的前庭和耳蜗室的正常形态发生。我们的初步数据为我们的方法提供了原则证明。在对照鸡胚胎中，我们发现背外侧耳囊上皮由柱状到鳞状的形状变化，伴随着变薄和扩张而形成原始管袋。时空控制的功能丧失和功能获得实验表明，BMP/SMAD信号对这种细胞形状的改变既是必要的，也是充分的。此外，类似的鸡误表达实验揭示了在早期耳囊背腹模式和形态发生过程中调节BMP/SHH信号的共同交叉点。在小鼠中，我们发现耳囊来源的FGF3和FGF10信号，除了它们在前庭形态发生中众所周知的作用外，还需要启动耳蜗形态发生。然而，这些上皮信号并不是早期耳囊区域图案化所必需的，这在成纤维细胞生长因子缺乏的耳囊肿中是正常的。因此，我们建议检验以下具体假设：1)BMP/TGFss、FGFss和HH信号的时间整合控制着耳囊形态发生的三个关键早期步骤：原始通道生长、原基分为垂直和侧向管囊以及初始耳蜗囊生长；2)这些信号协调耳囊区域和/或细胞命运的指定与相关细胞行为的变化。我们的建议利用了一组成熟研究人员的独特专业知识，在两个具有互补优势的动物模型中使用了最先进的分子遗传学和胚胎学技术，这将阐明在驱动生长因子信号下游关键形态发生步骤的机制方面的重要差异和相似之处。这将为该领域的发展提供一种新的理解，即信号通路如何整合以控制前庭和耳蜗形态发生的启动，以及这些信号如何协调细胞命运的指定和细胞行为的变化，以启动和塑造正常功能的膜迷路。这些信息为理解并最终预防人类听力损失提供了必要的基础。