Transcriptional regulation of hair-cell progenitors in the zebrafish lateral line

项目摘要 听力损失是一种可能使人虚弱的疾病，有3000多万人受到不同程度的影响。 在美国的个人。通常由机械感觉毛细胞的破坏引起 内耳，人类的大多数听力损失是永久性的，因为这些细胞不是天生的 补充好了。与人类耳朵的毛细胞不同，包括鱼类在内的非哺乳动物脊椎动物的毛细胞， 两栖动物和包括鸟类在内的爬行动物可以在一生中再生。尽管进行了广泛的研究， 这种差异的分子和细胞基础还不是很清楚。因为一个更完整的 对非哺乳动物模型系统中毛细胞再生的理解将促进这一发展 在听力损失的再生疗法中，我们目前的研究重点是阐明耳聋的机制。 在这样一个系统中，毛细胞再生，斑马鱼侧线。侧线包括阵列 位于表面的含有毛细胞的器官，称为神经肥大，用于检测水的移位。 我们已经设计了转基因标记和分离推测的祖细胞的程序-称为 套细胞--被认为在神经肥大再生过程中产生毛细胞的细胞。微阵列 分析表明，许多基因在外套细胞中也高度特异地表达。 作为基因，其在这些细胞中的表达受到耳毒性侮辱的调节。生成的数据 SET使我们处于一个独特的位置来确定哪些分子途径激活或抑制 祖细胞的增殖和随后毛细胞的替换。在最好的候选人中 控制祖细胞增殖的基因是那些编码跨膜蛋白Tspan1的基因 而原钙粘附素Fat1a和Fat1b在套细胞中高度丰富，并向下- 在再生过程中受到调节。我们建议使用功能丧失(反义介导的基因敲除 和现有的突变系)以及功能增益(mRNA介导的过度表达和 通过可诱导的转基因系统进行错误表达)以测试Tspan1、Fat1a和 脂肪1b在毛细胞发育和再生中的作用。通过这些研究，我们希望揭开之前 毛细胞再生的分子机制尚未被了解，这可能有助于 听力损失治疗的未来发展。

Project Summary Hearing loss is a potentially debilitating condition that afflicts to varying extents more than 30 million individuals in the United States. Commonly caused by destruction of the mechanosensory hair cells in the inner ear, most hearing loss in humans is permanent because these cells are not naturally replenished. Unlike those in the human ear, hair cells of non-mammalian vertebrates including fishes, amphibians, and reptiles including birds can regenerate throughout life. Despite extensive research, the molecular and cellular bases of this difference are not yet well understood. Because a more complete comprehension of hair-cell regeneration in non-mammalian model systems will foster the development of regenerative therapies for hearing loss, our current research focuses on elucidating the mechanism of hair-cell regeneration in one such system, the zebrafish lateral line. The lateral line comprises an array of superficially located hair cell-containing organs called neuromasts that detect water displacement. We have devised procedures for transgenically labeling and isolating the putative progenitors—called mantle cells—that are thought to give rise to hair cells in neuromasts during regeneration. Microarray analysis has revealed numerous genes that are highly and specifically expressed in mantle cells, as well as genes whose expression in these cells is modulated in response to ototoxic insult. The resulting data set places us in a unique position to determine which molecular pathways activate or repress the proliferation of progenitors and the subsequent replacement of hair cells. Among the top candidate genes for controlling progenitor proliferation are those encoding the transmembrane protein Tspan1 and the protocadherins Fat1a and Fat1b, which are highly enriched in mantle cells and are down- regulated during regeneration. We propose to use loss-of-function (antisense-mediated knockdown and existing mutant lines) as well as gain-of-function (mRNA-mediated overexpression and misexpression by means of an inducible transgenic system) to test the functions of Tspan1, Fat1a, and Fat1b in hair-cell development and regeneration. Through these studies we hope to uncover previously unappreciated molecular mechanisms governing hair-cell regeneration, which may contribute to the future development of therapies for hearing loss.