Immunolocalization of the water channel, aquaporin-5 (AQP5), in the rat digestive system
Immunolocalization of the water channel, aquaporin-5 (AQP5), in the rat digestive system
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DOI：
10.1679/aohc.66.307
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发表时间：
2003-10-01
影响因子：
--
通讯作者：
Takata, K
中科院分区：
文献类型：
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作者：
Matsuzaki, T;Tajika, Y;Takata, K
水通道蛋白-5（AQP 5）是膜水通道水通道蛋白的一种亚型，在唾液腺和泪腺中表达。本研究观察了AQP 5在大鼠消化系统中的表达及免疫组织化学定位。RT-PCR分析显示，AQP 5在颌下腺、舌、胃体、幽门区、十二指肠和肝脏中表达。使用AQP 5特异性抗体的免疫荧光显微镜显示，AQP 5蛋白存在于舌头的小唾液腺、幽门腺和十二指肠腺中。为了区分上皮细胞质膜的顶端和基底侧区域，进行AQP 5和紧密连接蛋白occludin的双重免疫荧光染色。在小唾液腺中，AQP 5存在于浆液性和混合性分泌端部分。AQP 5定位于分泌细胞的顶膜，包括以occludin为界的细胞间分泌小管。在更高的放大倍数下，可以看到沿着顶膜的AQP 5标记的Ω形压痕，这表明顶膜在胞吐中的动态过程。在基底外侧区仅检测到弱的AQP 5标记。在胃中，在幽门腺分泌细胞的顶膜中检测到AQP 5。在十二指肠中，AQP 5仅限于十二指肠腺，在那里它被定位于顶膜。AQP 5在肠腺和绒毛细胞中均未检测到。这些观察结果表明，AQP 5主要定位于顶膜，包括小唾液腺，幽门腺和十二指肠腺的分泌细胞的细胞间分泌小管。AQP 5似乎在这些腺体中的水转移中起重要作用。
Aquaporin-5 (AQP5), an isoform of membrane water channel aquaporins, is expressed in the salivary and lacrimal glands. We surveyed the expression and immunohistochemical localization of AQP5 in the rat digestive system. RT-PCR analysis revealed that AQP5 is expressed in the submandibular gland, tongue, gastric corpus, pyloric region, duodenum, and liver. Immunofluorescence microscopy using AQP5-specific antibodies showed that AQP5 protein is present in the minor salivary glands of the tongue, the pyloric glands, and duodenal glands. To distinguish apical and basolateral domains of the plasma membrane of epithelial cells, double-immunofluorescence staining for AQP5 and tight junction protein occludin was performed. In the minor salivary gland, AQP5 was present in both the serous and mixed secretory end portions. AQP5 was found in the apical membrane of the secretory cells including intercellular secretory canaliculi demarcated with occludin. At higher magnifications, omega-shaped indentations of AQP5 labeling were seen along the apical membrane, suggesting a dynamic process for the apical membrane in exocytosis. Only weak labeling for AQP5 was detected in the basolateral domain. In the stomach, AQP5 was detected in the apical membrane of the pyloric gland secretory cells. In the duodenum, AQP5 was restricted to duodenal glands, where it was localized to the apical membrane. AQP5 was not detected in the intestinal glands or cells in the villi. These observations show that AQP5 is localized mainly in the apical membrane, including intercellular secretory canaliculi of secretory cells in the minor salivary glands, pyloric glands, and duodenal glands. AQP5 appears to play an important role in water transfer in these glands.