Defining the pathological mechanisms of hereditary hearing loss

项目摘要 已发现与各种形式的遗传性耳聋(HHL)相关的大量突变 很多基因。确定HHL基因的生理作用和突变的病理机制 在这些基因中发现的基因对于开发治疗HHL的药物很重要。这项研究将确定 SLC26A4和SLC26A5两个HHL基因突变的致病性和病理机制 SLC26A4编码一种阴离子转运蛋白Pendrin。这种基因的改变是常见的 遗传性听力损失的原因，该基因中已发现300多个错义突变。在……里面 为了确定这些突变的病理机制，了解这些突变是如何 影响垂蛋白的功能，以及功能表型如何与疾病表型相关。对这件事 END、蛋白表达、膜靶向和阴离子转运功能 在哺乳动物细胞系中具有特征。结果将映射到结构模型，以便 我们可以从机理上洞察垂丝蛋白和其他SLC26蛋白。大量的误会 在SLC26A4中发现的突变使这些努力系统化和彻底。 SLC26A5编码一种基于膜的马达蛋白prestin，它在 毛囊虫。它的电压驱动的运动活动，电动，被证明是正常耳蜗所必需的。 放大。然而，目前还不清楚电动如何在扩增过程中使用。 SLC26A5突变的病理特征一直不明确，因为缺乏这一点 基础知识。在这项研究中，我们将检验Prestin快速运动活动的重要性。 使用表达prestin的动物模型，该动物模型含有HHL相关突变，该突变显著减缓了 预浸胶的运动动力学。此外，最近在一名患者中发现的两个新的SLC26A5错义突变 先天性听力损失的特征将是为了进一步了解压力素如何在 耳蜗放大过程和OHC的维护。 疾病相关突变的功能特征不仅对评估它们的 致病性，但也有利于了解基因的正常生理作用和确定 基因产物的分子机制。这项研究的成功完成使我们能够明确地 SLC26A4和SLC26A5突变的病理特征。

Project Summary Numerous mutations associated with various forms of hereditary hearing loss (HHL) have been identified in many genes. Defining the physiological roles of HHL genes and the pathological mechanisms of mutations found in these genes is important for the development of remedies against HHL. This study will determine the pathogenicity and pathological mechanisms of mutations found in two HHL genes, SLC26A4 and SLC26A5. SLC26A4 encodes an anion transporter, pendrin. Alterations of this gene are one of the common causes of hereditary hearing loss, and over 300 missense mutations have been identified in this gene. In order to define the pathological mechanisms of these mutations, it is important to know how these mutations affect the function of pendrin and how the functional phenotypes correlate with disease phenotypes. To this end, protein expression, membrane targeting, and anion transport functions of mutated pendrin proteins will be characterized in a mammalian cell line. The results will be mapped onto a structural model so that mechanistic insights for pendrin and other SLC26 proteins can be obtained. The large number of missense mutations found in SLC26A4 makes these efforts systematic and thorough. SLC26A5 encodes a membrane-based motor protein, prestin, which is abundantly expressed in OHCs. Its voltage-driven motor activity, electromotility, is demonstrated to be essential for normal cochlear amplification. However, it remains unclear how electromotility is used in the amplification process. Pathological characterizations of SLC26A5 mutations have been ambiguous due to the lack of this fundamental knowledge. In this study, the importance of the rapid motor activity of prestin will be examined using an animal model expressing prestin harboring an HHL-associated mutation that significantly slows the motor kinetics of prestin. In addition, two novel SLC26A5 missense mutations recently found in a patient with congenital hearing loss will be characterized in order to further gain insights as to how prestin contributes to the cochlear amplification process and OHC maintenance. Functional characterization of disease-associated mutations is not only important for assessing their pathogenicity, but also beneficial for appreciating the normal physiological roles of genes and defining the molecular mechanisms of the gene products. Successful completion of this study allows unequivocal pathological characterization of mutations found in SLC26A4 and SLC26A5.!