ZEBRAFISH: A POTENTIAL MODEL FOR MAMMALIAN HAIR CELL DEATH AND REGENERATION

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 听觉毛细胞是脊椎动物将声音信号转化为神经信号的感觉细胞，从而提供听力能力。在哺乳动物中，当这些终末分化细胞受损或丢失时，结果是永久性的听力丧失，因为丢失的哺乳动物毛细胞不能再生。在鱼类和鸟类中，受损的听觉感觉上皮具有再生新毛细胞的能力，从而恢复听力。最近的研究表明，金鱼在噪声暴露后表现出结构(毛细胞)和功能(听力)恢复。为了充分了解什么是正常的细胞过程导致鱼类再生，了解特定基因如何调节毛细胞生长(增殖和转分化)是必不可少的。这个项目的总体目标是研究斑马鱼毛细胞再生的过程，因为斑马鱼已经成为研究许多细胞途径的基因表达的有效模型。目前的研究有三个目标：1)利用免疫细胞化学方法确定噪声暴露斑马鱼毛细胞死亡和再生的时程；2)确定斑马鱼在噪声暴露后听力功能恢复的时程(使用听性脑干反应)；3)利用RT-PCR和微阵列技术检测斑马鱼耳朵毛细胞死亡和再生过程中的基因表达。我们最初对检测三个基因(p27Kip1、Atoh1和Rb1)的表达感兴趣。这些基因最近被证明可以调节哺乳动物的毛细胞发育。我们进行了一个微阵列实验，检测了毛细胞生成过程中的基因表达，上面三个感兴趣的基因并没有受到高度调控，但生长激素和其他一些基因受到了高度调控。最近，我们使用显著受调控的基因，用实时聚合酶链式反应验证了我们的微阵列实验。这些研究将为毛细胞再生研究的未来研究提供基础，并可能在毛细胞增殖与治疗耳聋的新疗法的开发之间建立联系方面至关重要。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Auditory hair cells are the sensory cells that transduce acoustical signals into neural ones in vertebrates, thus providing the ability to hear. In mammals, when these terminally-differentiated cells are damaged or lost, the result is permanent loss of hearing since lost mammalian hair cells do not regenerate. In fish and birds, damaged auditory sensory epithelia have the capability of regenerating new hair cells, resulting in recovery of hearing. Recent studies show that goldfish exhibit both structural (hair cells) and functional (hearing) recovery following noise exposure. To fully understand what normal cellular processes lead to regeneration in fishes, knowledge of how specific genes mediate hair cell growth (proliferation and transdifferentiation) is essential. The overall goal of this project is to study the process of hair cell regeneration in zebrafish, since zebrafish has become a productive model for studying the gene expression of many cellular pathways. The current proposal has three aims directed at this goal: 1) to determine the time course of hair cell death and regeneration in noise-exposed zebrafish (using immunocytochemistry); 2) to determine the time course of functional recovery of hearing following noise exposure in zebrafish (using auditory brainstem response); and 3) to examine gene expression during the process of hair cell death and regeneration in the zebrafish ear using rtPCR and microarray analysis. We were initially interested in examining expression of three genes (p27Kip1, Atoh1, and Rb1). These genes have recently been shown to regulate hair cell development in mammals. We have performed a microarray experiment that examined gene expression during the process of hair cell generation, and the three genes of interest above were not highly regulated, but growth hormone and a number of other genes were. We recently validated our microarray experiments with real-time PCR using significantly regulated genes. These studies will provide a basis for future investigations in hair cell regeneration research and may be critical in establishing a link between hair cell proliferation and development of new therapeutics to treat deafness.