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

项目摘要 听力损失是一种潜在的使人衰弱的疾病，在不同程度上困扰着3000多万人。 在美国的个人。通常是由机械感觉毛细胞的破坏引起的， 内耳，人类的大多数听力损失是永久性的，因为这些细胞不是自然的， 补充。与人耳不同，非哺乳类脊椎动物包括鱼类的毛细胞， 两栖动物和爬行动物，包括鸟类，一生都可以再生。尽管进行了广泛的研究， 这种差异的分子和细胞基础还没有被很好地理解。因为一个更完整的 在非哺乳动物模型系统中对毛细胞再生的理解将促进 再生疗法治疗听力损失，我们目前的研究重点是阐明的机制， 在一个这样的系统，斑马鱼侧线毛细胞再生。侧线包括阵列， 位于表面的含有毛细胞的器官，称为神经乳突，用于检测水的位移。 我们已经设计了转基因标记和分离推定的祖细胞的程序， 套细胞--被认为在神经瘤再生过程中产生毛细胞。微阵列 分析显示，许多基因在套膜细胞中高度特异表达， 这些基因在这些细胞中的表达响应于耳毒性损伤而被调节。结果数据 set使我们处于一个独特的位置，以确定哪些分子途径激活或抑制 祖细胞的增殖和随后的毛细胞替换。在候选人中， 控制祖细胞增殖的基因是编码跨膜蛋白Tspan 1的基因 和原钙粘蛋白Fat 1a和Fat 1b，它们在套膜细胞中高度富集，并在 在再生过程中进行调节。我们建议使用功能丧失（反义介导的敲除） 和现有的突变株系）以及功能获得性（mRNA介导的过表达和 通过诱导型转基因系统的方法检测Tspan 1、Fat 1a和 fat 1b在毛细胞发育和再生中的作用。通过这些研究，我们希望能够揭示以前 未被重视的毛细胞再生的分子机制，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.