Quantitative Analysis of Aquaporin Expression Levels during the Development and Maturation of the Inner Ear
Quantitative Analysis of Aquaporin Expression Levels during the Development and Maturation of the Inner Ear
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DOI：
10.1007/s10162-016-0607-3
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发表时间：
2017-04-01
影响因子：
2.4
通讯作者：
Yamamoto, Norio
中科院分区：
文献类型：
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作者：
Miyoshi, Takushi;Yamaguchi, Taro;Yamamoto, Norio
水通道蛋白 (AQP) 是一类小膜蛋白，可沿渗透梯度跨质膜运输水分子。哺乳动物表达 13 种 AQP 亚型，包括最近报道的“亚细胞 AQP”AQP11 和 12。每个器官都表达 AQP 亚型的特定子集，在内耳中，AQP 对于两种不同液体（内淋巴和外淋巴）的建立和维持至关重要。为了评估 AQP 在内耳功能建立过程中的贡献，我们使用定量逆转录聚合酶链反应来量化在内耳整个发育和成熟过程中所有已知 AQP 的表达水平。通过系统和纵向定量，我们发现 AQP11 主要在内耳中持续表达，并且几个 AQP 的表达水平遵循特征纵向模式：增加（Aqp0、1 和 9）、减少（Aqp6、8 和 12）以及 E18 上的表达峰值（Aqp2、5 和 7）。特别是，Aqp9 的表达水平在 P3-P21 期间增加了 70 倍。我们还对 Aqp11 进行了原位杂交，并确定了 Aqp11 在外毛细胞中的独特定位。 AQP9 的免疫组织化学揭示了其定位于 Corti 器官内的支持细胞和根细胞中。这些细胞中出现AQP9表达是在P3-P21期间，这与其表达水平的显着增加相一致。结合这些量化和定位数据，我们讨论了这些 AQP 对内耳功能的可能贡献。
Aquaporins (AQPs) are a family of small membrane proteins that transport water molecules across the plasma membrane along the osmotic gradient. Mammals express 13 subtypes of AQPs, including the recently reported "subcellular AQPs", AQP11 and 12. Each organ expresses specific subsets of AQP subtypes, and in the inner ear, AQPs are essential for the establishment and maintenance of two distinct fluids, endolymph and perilymph. To evaluate the contribution of AQPs during the establishment of inner ear function, we used quantitative reverse transcription polymerase chain reaction to quantify the expression levels of all known AQPs during the entire development and maturation of the inner ear. Using systematic and longitudinal quantification, we found that AQP11 was majorly and constantly expressed in the inner ear, and that the expression levels of several AQPs follow characteristic longitudinal patterns: increasing (Aqp0, 1, and 9), decreasing (Aqp6, 8, and 12), and peak of expression on E18 (Aqp2, 5, and 7). In particular, the expression level of Aqp9 increased by 70-fold during P3-P21. We also performed in situ hybridization of Aqp11, and determined the unique localization of Aqp11 in the outer hair cells. Immunohistochemistry of AQP9 revealed its localization in the supporting cells inside the organ of Corti, and in the root cells. The emergence of AQP9 expression in these cells was during P3-P21, which was coincident with the marked increase of its expression level. Combining these quantification and localization data, we discuss the possible contributions of these AQPs to inner ear function.