Role of Supporting Cells in Cochlear Hair Cell Regeneration

支持细胞在耳蜗毛细胞再生中的作用

• 批准号: 7636384
• 负责人: Sonia M Rocha-Sanchez
• 金额: $ 14.45万
• 依托单位: CREIGHTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-02-15 至 2012-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7636384
• 关键词: Ablation; Adult; Alleles; Animals; Apoptosis; Back; Biochemical; Birth; Breeding; Bypass; Cell Cycle; Cell Cycle Progression; Cell Death; Cell Differentiation process; Cell Proliferation; Cells; Cessation of life; Clinical; Cochlea; Complex; Cyclins; Data; Double Effect; Ear; Effectiveness; Embryonic Development; Epithelium; Excision; Exhibits; Family; Figs - dietary; Gene Dosage; Gene Proteins; Genetic; Genetic Recombination; Genetically Engineered Mouse; Genotype; Goals; Hair Cells; Hearing; Hearing Impaired Persons; Inherited; Knockout Mice; Labyrinth; Maintenance; Measures; Mediating; Mitotic; Molecular; Mus; Mutate; Natural regeneration; Organ of Corti; Organism; Partner in relationship; Pathway interactions; Penetrance; Phase Transition; Phenotype; Proliferating; Proteins; RBL2 gene; Reporter; Research Project Grants; Retinoblastoma; Retinoblastoma Genes; Retinoblastoma Protein; Rodent; Role; Sensory; Sensory Hair; Supporting Cell; System; Tamoxifen; Testing; Therapeutic; Tissues; Transgenes; Transgenic Mice; Variant; Vertebrates; animal facility; cell type; cost; dosage; equilibration disorder; hair cell regeneration; hearing impairment; insight; member; mutant; offspring; paralogous gene; postnatal; research study; restoration; spatiotemporal; success; transdifferentiation; tumor

DESCRIPTION (provided by applicant): The retinoblastoma family of pocket proteins (pRB) is a central node impossible to bypass during the cell cycle. Dynamic variation in the ratios of all three hyper-phosphorylated paralogs is directly correlated with cell proliferation, cellular quiescence, and apoptosis, in nearly all cells in the body. Compared to other tissues, the biochemical and molecular pathways of the pRBs in the inner ear are relatively unexplored. Likewise, the effects of quantitative manipulation of this central node in the inner ear sensory epithelia cells and its potential to promote hair cell (HC) and supporting cell (SC) proliferation is yet to be determined. Establishing therapeutic measures that slow the progression of hearing loss or restoration of lost hearing are major clinical challenges. Differentiated HCs are especially susceptible to inherited and environmental pathogenic insults. Mammalian HCs proliferate during embryogenesis, then exit the cell cycle, differentiate and become functionally mature. Adult mammalian HCs do not regenerate and HC death leads to irreversible neurosensory hearing loss and balance impairment. Recent advances have provided proof of principle for two sets of therapies: the use of the cyclin system or pocket protein gene (Rb1) to promote proliferation, and the effectiveness of Atoh1 to induce transdifferentiation (TD) SC into HC. Combined, these two approaches can mimic the ability of lower vertebrates to regenerate HC. However, beyond the proof of principle, current attempts to regulate cell cycle through genetic ablation of Rb1 are not likely to safely repopulate lost HC and SC. Preliminary assessment of the three pRB members, Rb1, Rbl1 (p107) and Rbl2 (p130) revealed that all of them are expressed in the inner ear and exhibit extensive differences and similarities with one another along and across the organ of Corti. Deletion of any pRB leads to additional rows of HC and SC. Using various conditional and complete null mutants, we will investigate the role of all three pRBs in the ear and determine the ability of SCs to proliferate as a result of quantitative manipulation of the inherent ratio of the pRBs in the inner ear sensory epithelia (aim 1). Additionally, we will analyze pRBs-mediated proliferation in congenitally deaf (dreidel) mice (aim 2). Results obtained from our proposed study will provide insights on the therapeutic applicability of pRB manipulation in SC proliferation and HC regeneration. Relevance: Adult mammalian inner ear sensory hair cells (HC) do not regenerate and their death leads to irreversible neurosensory hearing loss and balance impairment. Our research project aims to apply current approaches to quantitatively manipulate the dosage of genes involved on cell proliferation and stimulate HC regeneration.

描述（由申请方提供）：视网膜母细胞瘤口袋蛋白家族（pRB）是细胞周期中无法绕过的中心节点。在体内几乎所有细胞中，所有三种超磷酸化旁系同源物的比率的动态变化与细胞增殖、细胞静止和细胞凋亡直接相关。与其他组织相比，内耳中pRB的生化和分子途径相对未被探索。同样，定量操作内耳感觉上皮细胞中的该中央节点的效果及其促进毛细胞（HC）和支持细胞（SC）增殖的潜力尚待确定。建立减缓听力损失进展或恢复听力损失的治疗措施是主要的临床挑战。分化的HC特别容易受到遗传和环境致病性损伤。哺乳动物HC在胚胎发生期间增殖，然后退出细胞周期，分化并变得功能成熟。成年哺乳动物HC不能再生，HC死亡导致不可逆的感觉神经性听力损失和平衡障碍。最近的进展提供了两套疗法的原则证明：使用细胞周期蛋白系统或口袋蛋白基因（Rb 1），以促进增殖，和Atoh1诱导转分化（TD）SC到HC的有效性。结合起来，这两种方法可以模拟低等脊椎动物再生HC的能力。然而，除了原理证明，目前试图通过基因消融Rb 1调节细胞周期不太可能安全地重新填充丢失的HC和SC。三个pRB成员，Rb 1，Rbl1（p107）和Rbl2（p130）的初步评估显示，所有这些都在内耳中表达，并表现出广泛的差异和相似性，彼此沿着和跨Corti器官。删除任何pRB导致额外的行HC和SC。使用各种条件和完全无效突变体，我们将调查所有三个pRB在耳中的作用，并确定SC增殖的能力作为定量操作的固有比例的pRB在内耳感觉上皮细胞（目的1）。此外，我们将在先天性耳聋（dreidel）小鼠中分析pRB介导的增殖（目的2）。从我们提出的研究中获得的结果将提供关于pRB操纵在SC增殖和HC再生中的治疗适用性的见解。 相关性：成年哺乳动物内耳感觉毛细胞（HC）不能再生，它们的死亡导致不可逆的神经感觉性听力损失和平衡障碍。我们的研究项目旨在应用当前的方法来定量操纵参与细胞增殖和刺激HC再生的基因的剂量。