Cell cycle in development and regeneration of the inner ear

内耳发育和再生中的细胞周期

• 批准号: 7391369
• 负责人: Neil Segil
• 金额: $ 9.15万
• 依托单位: HOUSE RESEARCH INSTITUTE
• 依托单位国家: 美国
• 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/7391369
• 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

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.

哺乳动物感觉毛细胞的丧失会导致永久性耳聋，因为再生不会 发生。再生能力的丧失与体内的特化支持细胞的无力有关 Corti的器官开始分裂，以响应毛细胞的死亡。我们采取了一种发展的方法 这个问题。我们的希望是，通过彻底了解器官细胞的过程 Corti在胚胎发育过程中停止分裂，我们将深入了解为什么没有发生再生。正在做 因此，我们希望为耳聋的治疗干预提供工具和靶点。 在Corti器官的发育过程中，细胞增殖的控制与 细胞分化和图案化的过程(Ruben，1968)。我们已经证明，依赖于细胞周期蛋白的 蛋白激酶抑制剂p27Klp1需要对这种协调进行计时。在p27Klp1突变小鼠中，细胞周期退出是 延迟，导致细胞过剩，扰乱毛细胞组织的有序模式，以及 耳聋(Chen和Segil，1999)。 尽管人们普遍认为p27Klp1的丰度是在转录后水平上调节的 通过控制蛋白质周转，我们的结果表明p27Klp1的转录调控在很大程度上是， 虽然不是全部，但负责确定成熟器官中的细胞数量。其他内容 初步数据表明，Notch通路信号可能是调节p27转录的关键因素 在科尔蒂器官形成过程中。在具体目标1中，我们分析了Notch信号在空间和空间分布中的作用。 Corti器官胚胎发生过程中p27Klp1转录的时间调控。 尽管p27Klp1的转录调控很重要，但我们观察到在Skp2突变体中 小鼠的细胞周期出口和器官的Corti结构也存在缺陷。Skp2是SCF-泛素的一部分 参与调节p27Klp1蛋白周转的连接酶复合体。在具体目标2中，我们讨论了 P27Klp1调控的转录后机制。 最后，在具体目标3和4中，我们通过研究p27Klp1直接解决了再生问题 对出生后支持细胞的调节。我们最近开发了一些技术，使我们能够净化 出生后支持细胞，并在体外培养它们。在这样做的过程中，我们发现围产期支持 细胞保留了重新进入细胞周期和分裂的能力，而来自P14小鼠的支持细胞则无法 这样做。P14支持细胞下调p27Kip1的能力改变是部分原因 细胞分裂受阻，导致再生不足。这一特定的目的是研究分子 我们假设的依赖年龄的p27调节改变的基础是缺乏再生的基础。 在哺乳动物的内耳。