Hearing loss in claudin 11-null mice

描述（由申请人提供）：本项目的长期目标是确定内耳血管纹中紧密连接的功能，并确定组成位于中阶周围的紧密连接的Claudin家族成员的多样性是否具有重叠或非重叠特性。从这些研究中获得的知识将为血管纹在听力和钾循环到内淋巴中的作用提供深刻的见解。具体目的是：1）检验Claudin基因敲除小鼠的内耳病理学源于形态学缺陷的假设。Claudin 11在E13.5胚胎的发育中前庭耳蜗器中以及在成年人中表达，并且将寻找在发育期间和出生后可以解释敲除小鼠中的病理学的总体结构变化的证据。2)以检验Claudin 11缺失小鼠表现出早期听力缺陷的假设。年轻的成年敲除小鼠表现出升高的听觉脑干反应（ABR）阈值，这表明听力损失。在不同年龄对ABR的进一步测试以及耳蜗内电位和DPOAE的测量将揭示这种表型是进行性的还是在小鼠正常开始听力时存在。3)优化用于在血管纹基底细胞中表达异源基因的转基因盒。已经在手的基底细胞特异性增强子元件将位于紧密连接蛋白11基因内，并用于驱动β-半乳糖苷酶报告基因在耳蜗中的表达。将表征报告基因表达，以在耳蜗中表达几种紧密连接蛋白cDNA，试图挽救紧密连接蛋白11缺失小鼠的听力损失。

DESCRIPTION (provided by applicant): The long term goals of this project are to define the functions of tight junctions in Stria vascularis of the inner ear and to determine if the diversity of Claudin family members that comprise fight junctions located around Scala media have overlapping or non-overlapping properties. The knowledge gained from these studies will provide deep insights into the roles of the stria vascularis in hearing and potassium recycling to the endolymph. The specific aims are: 1) to test the hypothesis that inner ear pathology in Claudin//-null mice stems from morphological defects. Claudin 11 is expressed in the developing vestibulocochlear apparatus of embryos from E13.5 as well as in adults and evidence of gross structural changes during development and postnatally that could account for the pathology in the knockout mice will be sought. 2) to test the hypothesis that Claudin 11-null mice exhibit early hearing defects. Young adult knockout mice exhibit elevated auditory brainstem response (ABR) thresholds which indicate hearing loss, Further testing of ABRs as well as measurements of endocochlear potentials and DPOAEs at different ages will reveal if this phenotype is progressive or present at the time mice normally start to hear. 3) to optimize a transgene cassette for the expression of heterologous genes in basal cells of Stria vascularis. Basal cell-specific enhancer elements already in-hand will be located within the Claudin 11 gene and used to drive expression of a beta-galactosidase reporter gene in the cochlea, Reporter expression will be characterized with a view to expressing several claudin cDNAs in the cochlea in attempts to rescue hearing loss in Claudin 11-null mice.