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: 8593973
• 负责人: Ana Benito-Gonzalez
• 金额: $ 5.22万
• 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 2016-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8593973
• 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殊感觉上皮介导。这种上皮的正常发育和维持对听力至关重要，而这些细胞的缺失会导致耳聋。虽然包括鸟类和爬行动物在内的许多脊椎动物能够再生受损的毛细胞，但哺乳动物（包括人类）不能保留这种能力，导致受伤后永久失聪。基因疗法是一种很有前途的治疗方法，也许有一天能让失聪的人恢复听力。然而，在基因治疗能够靶向基因表达之前，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哺乳动物耳蜗发育过程中毛细胞分化起始的分子机制。我们实验室发现Hey1和Hey2在耳蜗分化过程中表达，与毛细胞分化发生重叠，并在分化过程中迅速下调。不仅如此，我们的研究结果还表明，这两种转录抑制因子都受到Shh信号通路的控制。然而，缺乏Shh信号似乎不足以引发毛细胞分化。我们的初步结果表明，激活素A存在于耳蜗感觉上皮分化前，参与触发毛细胞分化。简而言之，在目的1中，我们将描述Hey1Hey2双敲除中毛细胞分化的时间，在目的2中，我们将确定是否丢失