Regulation of inner ear development by FGF signals and effectors

FGF 信号和效应器调节内耳发育

• 批准号: 10552052
• 负责人: Suzanne L Mansour
• 金额: $ 41.41万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-02-05 至 2026-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10552052
• 关键词: Ablation; Address; Affect; Age; Auditory; Candidate Disease Gene; Cell Differentiation process; Cell Survival; Cells; Cochlea; Cochlear implant procedure; Data; Defect; Development; Dominant-Negative Mutation; Doxycycline; Epithelium; Equilibrium; FGF10 gene; FGF3 gene; Fibroblast Growth Factor; Fibroblast Growth Factor Receptors; Future; Ganglia; Generations; Genes; Goals; Health Care Costs; Hearing; In Vitro; Individual; Investigation; Knockout Mice; Knowledge; Labyrinth; Ligands; Maintenance; Mediating; Mesenchymal; Messenger RNA; Molecular; Morphogenesis; Morphology; Mus; Neurons; Otic Placodes; Pattern; Phenotype; Proliferating; Receptor Protein-Tyrosine Kinases; Regulation; Repression; Role; Sensory; Signal Pathway; Signal Repression; Signal Transduction; Signaling Molecule; Specific qualifier value; System; Testing; Tissues; Transplantation; cell type; combinatorial; conditional knockout; conditional mutant; extracellular; fibroblast growth factor receptor 2b; gene function; genetic approach; genome-wide analysis; hearing impairment; hearing restoration; in vivo; inner ear development; light intensity; loss of function; malformation; molecular marker; mouse model; mutant; nerve supply; neural; neuroblast; neurogenesis; novel; otoconia; overexpression; permanent hearing loss; social; spiral ganglion; transcription factor

Morphogenesis of the inner ear epithelium requires coordinated deployment of several signaling pathways and disruptions cause abnormalities of hearing and/or balance. With the advent of cochlear implantation to treat hearing loss even in cases of inner ear malformation, it is critical to understand exactly how such malformations affect the auditory ganglia and innervation. Also, in light of the intense focus on in vitro generation of inner ear cell types for transplantation and in vivo manipulation of developmental signaling molecules to promote differentiation of various inner ear cells for hearing restoration, elucidating the roles and regulation of such signals and their effectors governing otic differentiation and morphogenesis are necessary to advance treatment. The genes encoding FGF3 and FGF10, ligands that signal through FGFR2b and FGFR1b, are expressed dynamically throughout otic development in both epithelial and ganglion domains. Studies conducted by the Mansour Lab of both conventional Fgf3 and Fgf10 conditional knockout mice and those expressing a doxycycline-inducible ligand trap (dnFGFR2b) that rapidly inhibits signaling through both FGFR1b and FGFR2b, showed that Fgf3 and Fgf10 are not required in the placode lineage for otocyst formation, but are required subsequently for otocyst patterning, neuroblast maintenance, epithelial proliferation and both vestibular and cochlear morphogenesis. Furthermore, the first genome wide analyses of otocyst mRNA revealed FGFR2b/1b signaling targets that define novel candidates for genes involved in otic morphogenesis and function. This proposal has two Aims addressing the hypotheses that 1) FGFR2b/1b signaling is required continuously for both otic neuroblast specification and maintenance, and that at later stages, mesenchymal signaling, as well as that in the epithelial and ganglion domains, is required for cochlear epithelial differentiation and ganglion maintenance and 2) FGFR2b/1b downstream target genes mediate some or all of the effects of FGFR2b/1b signaling on otic morphogenesis and gangliogenesis. To determine the early role of FGFR2b/1b signaling in otic ganglion formation and its later role in epithelial differentiation and ganglion maintenance, DOX-induced ubiquitous and CRE-limited expression of dnFGFR2b will be employed and morphology and molecular markers of otic patterning, proliferation and survival in both tissues will be assessed. To determine the roles of downstream targets of FGFR2b/1b signaling, two genes encoding transcription factors that are activated by FGFR2b/1b signaling and one gene encoding a BMP signaling regulator that is repressed by FGFR2b/1b signaling will be studied. Otic conditional mutants will be generated for each gene, and their morphologic and functional development will be assessed. In addition, the extent to which the BMP regulator contributes to the dnFGFR2b phenotypes and the effects of overexpressing the BMP regulator will be assessed. The results will contribute new knowledge that will facilitate future efforts to manipulate the FGF signaling system for hearing restoration.

内耳上皮的形态发生需要几种信号通路的协调部署 干扰会导致听力和/或平衡的异常。随着人工耳蜗的出现 即使在内耳畸形的情况下，听力损失，至关重要的是要准确了解这种畸形如何 影响听觉神经节和神经。另外，鉴于强烈的关注内耳的体外产生 用于移植和体内操纵发育信号分子的细胞类型以促进 各种内耳细胞的分化以听见恢复，阐明了这种作用和调节 信号及其构造的效应子是针对性分化和形态发生的信号，对于提高治疗是必要的。 用FGFR2B和FGFR1B发出信号的FGF3和FGF10的基因被表达 在上皮和神经节结构域中动态动态发育。研究 常规FGF3和FGF10条件敲除小鼠的Mansour实验室和表达 强力霉素诱导的配体陷阱（DNFGFR2B）迅速抑制通过FGFR1B和 FGFR2B，表明在placode谱系中不需要FGF3和FGF10以进行耳囊形成，但是 随后需要进行耳囊​​性图案，神经细胞维持，上皮增殖以及两者 前庭和耳蜗形态发生。此外，耳尾mRNA的第一个基因组广泛分析显示 FGFR2B/1B信号传导靶标，该靶标定义了参与耳形形态发生和功能的基因的新候选物。 该提案有两个目的，以解决1）需要连续需要FGFR2B/1B信号的假设 对于耳神经细胞规范和维护，并且在后期阶段，间充质信号传导 因为在上皮和神经节域中，上皮分化和神经节是必需的 维护和2）FGFR2B/1B下游靶基因介导FGFR2B/1B的某些效果 关于耳形形态发生和神经节发生的信号。确定FGFR2B/1B信号在耳中的早期作用 神经节的形成及其后来在上皮分化和神经节维持中的作用，DOX诱导 DNFGFR2B的无处不在和Cre限制的表达将被采用，形态学和分子标记 将评估两种组织中的耳模式，增殖和存活。确定角色 FGFR2B/1B信号传导的下游靶标，两个编码转录因子的基因被激活 FGFR2B/1B信号传导和一个编码BMP信号调节器的基因，该基因被FGFR2B/1B抑制 信号将研究。每个基因以及它们的形态学和形态和 功能开发将被评估。此外，BMP调节器在多大程度上有助于 将评估DNFGFR2B表型和过表达BMP调节剂的影响。 结果将有助于新知识，以促进未来的努力操纵FGF信号 听力修复系统。