Role of Shh-Hey1/Hey2 and Activin A in Hair Cell Differentiation

Shh-Hey1/Hey2 和激活素 A 在毛细胞分化中的作用

• 批准号: 8689751
• 负责人: Ana Benito-Gonzalez
• 金额: $ 5.51万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-07-01 至 2015-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8689751
• 关键词: Activins; Apical; Auditory; Birds; Cell Cycle; Cell Differentiation process; Cell Maturation; Cell physiology; Cells; Cochlea; Complex; Data; Development; Epithelium; Erinaceidae; Gene Expression; Generations; Genes; Genetic; Goals; Hair Cells; Hearing; Hearing Impaired Persons; Housing; Human; In Vitro; Individual; Injury; Knock-out; Knowledge; Labyrinth; Left; Maintenance; Mammals; Mediating; Mitosis; Molecular; Mus; Natural regeneration; Organ; Organ of Corti; Pathway interactions; Pattern; Play; Recovery; Regulation; Reptiles; Role; Sensory; Sensory Hair; Signal Pathway; Signal Transduction; Structure; Supporting Cell; Therapeutic; Time; Transcription Repressor/Corepressor; Transgenic Mice; Undifferentiated; Vertebrates; activin A; base; cell type; deafness; design; gene therapy; hearing impairment; in vivo; inhibitor/antagonist; member; mutant mouse model; notch protein; premature; progenitor; public health relevance; receptor; research study; smoothened signaling pathway; sound; tool

DESCRIPTION (provided by applicant): Sound perception is mediated through a specialized sensory epithelium made up of mechanosensory hair cells and supporting cells. The proper development and maintenance of this epithelium is critical for the ability to hear, and loss of these cells leads to deafness. While many vertebrates, including birds and reptiles, are able to regenerate damaged hair cells, mammals (including humans) do not retain this ability, resulting in permanent deafness after injury. Gene therapy is a potentially promising therapeutic approach that might one day allow for the recovery of hearing in deaf individuals. However, before gene therapy can target gene expression, the molecular mechanisms that underlie the generation of these sensory cells needs to be understood. The long term goal of this study is to uncover the molecular mechanisms regulating the initiation of hair cell differentiation in the developing mammalian cochlea. Our lab has found that Hey1 and Hey2 are expressed during cochlea differentiation, overlapping with the onset of hair cell differentiation and rapidly down-regulated as differentiation occurs. Not only that, but our results indicate that these two transcriptional repressors are under the control of Shh signaling pathway. However, lack of Shh signaling does not seem enough to trigger hair cell differentiation. Our preliminary results suggest that Activin A, present in the cochlea sensory epithelia before differentiation, is involve in triggering hair cell differentiation. Briefly, in aim1 we will characterize the timing of differentiation of hair cells in the Hey1Hey2 double knockout, in aim2 we will determine if loss of Hey2 or Hey1 and Hey2 diminishes Shh ability to delay hair cell differentiation, and, finally, in aim3 we will study the effects of different inhibitors of the Activin A pathway in vitro and determine the effects that loss of Activin A function has in hair cell differentiation. In this stuy we will use well-established genetic tools, including mouse transgenics and cochlea explant cultures, to study the effects of disrupting these pathways on hair cell differentiation and maturation. It is our hope that the experiments put forth in this application will advance our understanding of the genetic mechanism underlying the development and maintenance of sensory cell in the cochlea.

描述（由申请人提供）：声音感知通过由机械感觉毛细胞和支持细胞组成的特化感觉上皮介导。这种上皮细胞的正常发育和维持对听力至关重要，这些细胞的缺失会导致耳聋。虽然许多脊椎动物，包括鸟类和爬行动物，能够再生受损的毛细胞，但哺乳动物（包括人类）不保留这种能力，导致受伤后永久性耳聋。基因治疗是一种潜在的有前途的治疗方法，有一天可能会允许聋人听力恢复。然而，在基因治疗可以靶向基因表达之前，需要了解这些感觉细胞产生的分子机制。本研究的长期目标是揭示发育中的哺乳动物耳蜗毛细胞分化的分子调控机制。我们的实验室发现Hey1和Hey2在耳蜗分化过程中表达，与毛细胞分化的开始重叠，并随着分化的发生而迅速下调。不仅如此，我们的研究结果还表明，这两个转录抑制因子都受Shh信号通路的控制。然而，缺乏Shh信号似乎不足以触发毛细胞分化。我们的初步结果表明，激活素A，存在于分化前的耳蜗感觉上皮细胞，参与触发毛细胞分化。简而言之，在aim 1中，我们将表征Hey 1 Hey 2双敲除中毛细胞分化的时机，在aim 2中，我们将确定是否失去 Hey2或Hey1和Hey2降低Shh延迟毛细胞分化的能力，最后，在aim3中，我们将研究激活素A途径的不同抑制剂在体外的作用，并确定激活素A功能丧失对毛细胞分化的影响。在本研究中，我们将使用成熟的遗传工具，包括小鼠转基因和耳蜗外植体培养，来研究干扰这些通路对毛细胞分化和成熟的影响。我们希望本申请中提出的实验将促进我们对耳蜗感觉细胞发育和维持的遗传机制的理解。