Cell cycle in development and regeneration of the inner ear

内耳发育和再生中的细胞周期

基本信息

批准号：
7325690
负责人：
Neil Segil
金额：
$ 50.78万
依托单位：
HOUSE RESEARCH INSTITUTE
依托单位国家：
美国
项目类别：
财政年份：
1999
资助国家：
美国
起止时间：
1999-08-01 至 2011-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7325690
关键词：
Address Adult Affect Age Birds Cell Count Cell Cycle Cell Cycle Regulation Cell Death Cell Differentiation process Cell Proliferation Cell division Cells Cochlea Cochlear duct Complex Corwin Cyclin-Dependent Kinase Inhibitor Data Defect Development Differentiation and Growth Disruption Down-Regulation Embryonic Development F-Box Proteins Failure Family Figs - dietary Genes Genetic Genetic Transcription Goals Grant Hair Cells In Vitro Investigation Labyrinth Maintenance Mammals Methods Molecular Morphogenesis Mus Mutant Strains Mice Natural regeneration Normal Cell Notch Signaling Pathway Numbers Organ Organ of Corti Pathway interactions Pattern Perinatal Play Point Mutation Post-Transcriptional Regulation Process Proliferating Proteins Proteolysis Publishing Regulation Relative (related person)Reporting Research Personnel Role Ruthenium Ben SKP Cullin F-Box Protein Ligases Sensory Hair Series Signal Transduction Supporting Cell Techniques Tertiary Protein Structure Therapeutic Intervention Time Transcriptional Regulation Ubiquitin Vertebrates Wild Type Mouse age related base day deafness hair cell regeneration in vivo inhibitor/antagonist insight loss of function mutation mutant notch protein postnatal progenitor programs protein degradation response tool

项目摘要

Loss of sensory hair cells in mammals results in permanent deafness because regeneration does not occur. The loss of regenerative ability is tied to the inability of the specialized supporting cells within the organ of Corti to begin dividing in response to hair cell death. We have taken a developmental approach to this problem. Our hope is that by thoroughly understanding the process by which the cells of the organ of Corti stop dividing during embryogenesis, we will gain insight into why regeneration does not occur. In doing so, we hope to provide tools and targets for therapeutic intervention into the problem of deafness. During development of the organ of Corti, control of cell proliferation is tightly coordinated with the process of cell differentiation and patterning (Ruben, 1968). We have shown that the cyclin-dependent kinase inhibitor p27Klp1 is required for timing this coordination. In p27Klp1 mutant mice, cell cycle exit is delayed, leading to supernumerary cells, a disruption of the orderly pattern of hair cell organization, and deafness (Chen and Segil, 1999). Although p27Klp1 abundance is widely believed to be regulated at the post-transcriptional level through control of protein turnover, our results indicate that transcriptional regulation of p27Klp1 is largely, though not entirely, responsible for the determining the number of cells in the mature organ. Additional preliminary data indicates that Notch pathway signaling may be a key player in regulating p27 transcription during organ of Corti formation. In Specific Aim 1 we analyze the role of Notch signaling in the spatial and temporal regulation of p27Klp1 transcription during embryogenesis of the organ of Corti. In spite of the importance of p27Klp1 transcriptional regulation, we have observed that in Skp2 mutant mice, there is also a defect in cell cycle exit and organ of Corti structure. Skp2 is part of the SCF-ubiquitin ligase complex that is involved in regulating p27Klp1 protein turnover. In Specific Aim 2 we address the role of post-transcriptional mechanisms in the regulation of p27Klp1. Finally, in Specific Aims 3 and 4 we address the problem of regeneration directly, by studying p27Klp1 regulation in postnatal supporting cells. We have recently developed techniques that allow us to purify postnatal supporting cells and grow them in vitro. In doing so, we have discovered that perinatal supporting cells retain the capacity to reenterthe cell cycle and divide, while supporting cells from P14 mice are unable to do so. Changes in the ability of P14 supporting cells to down-regulate p27Kip1 are partly responsible for the block to cell division that results in the lack of regeneration. This specific aim investigates the molecular basis for the age-dependent change in p27 regulation that we hypothesize underlies the lack of regeneration in the mammalian innerear.

哺乳动物失去感觉毛细胞会导致永久性耳聋，因为再生不会发生。再生能力的丧失与体内专门支持细胞的无能力有关。柯蒂氏器响应毛细胞死亡而开始分裂。我们采取了发展的方针这个问题。我们希望通过彻底了解器官细胞的过程科尔蒂在胚胎发生过程中停止分裂，我们将深入了解为什么不发生再生。在做因此，我们希望为耳聋问题的治疗干预提供工具和目标。在柯蒂氏器的发育过程中，细胞增殖的控制与细胞分化和模式形成的过程（Ruben，1968）。我们已经证明，细胞周期蛋白依赖性需要激酶抑制剂 p27Klp1 来计时这种协调。在 p27Klp1 突变小鼠中，细胞周期退出是延迟，导致多余的细胞，毛细胞组织有序模式的破坏，以及耳聋（Chen 和 Segil，1999）。尽管人们普遍认为 p27Klp1 丰度在转录后水平受到调节通过控制蛋白质周转，我们的结果表明 p27Klp1 的转录调控很大程度上是，尽管不完全，但负责确定成熟器官中的细胞数量。额外的初步数据表明Notch通路信号可能是调节p27转录的关键因素柯蒂氏器形成期间。在具体目标 1 中，我们分析了 Notch 信号在空间和柯蒂氏器胚胎发生过程中 p27Klp1 转录的时间调控。尽管 p27Klp1 转录调控很重要，但我们观察到在 Skp2 突变体中小鼠的细胞周期退出和柯蒂结构器官也存在缺陷。 Skp2 是 SCF 泛素的一部分连接酶复合物参与调节 p27Klp1 蛋白周转。在具体目标 2 中，我们阐述了以下角色： p27Klp1 调节的转录后机制。最后，在具体目标 3 和 4 中，我们通过研究 p27Klp1 直接解决再生问题产后支持细胞的调节。我们最近开发了一些技术，可以净化产后支持细胞并在体外培养它们。在此过程中，我们发现围产期支持细胞保留重新进入细胞周期和分裂的能力，而 P14 小鼠的支持细胞则无法这样做。 P14 支持细胞下调 p27Kip1 能力的变化是造成这种情况的部分原因细胞分裂受阻，导致再生不足。这一特定目标研究了分子 p27 调节随年龄变化的基础，我们推测这是再生缺乏的基础在哺乳动物的内耳中。