Expression of the ammonia transporter proteins RhB glycoprotein and RhC glycoprotein in the intestinal tract
Expression of the ammonia transporter proteins RhB glycoprotein and RhC glycoprotein in the intestinal tract
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DOI：
10.1152/ajpgi.00418.2004
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发表时间：
2005-05-01
影响因子：
4.5
通讯作者：
Weiner, ID
中科院分区：
文献类型：
--
作者：
Handlogten, ME;Hong, SP;Weiner, ID
氨代谢在胃肠道生理学的多个方面都很重要，但氨在胃肠道中转运的机制仍不完全明确。本研究检测氨转运蛋白家族成员Rh B糖蛋白（RhBG）和Rh C糖蛋白（RhCG）在小鼠胃肠道中的表达。实时荧光定量RT-PCR扩增和免疫印迹分析表明，RhBG和RhCG的mRNA和蛋白质在胃，十二指肠，空肠，回肠和结肠中表达。免疫组化显示RhBG和RhCG的器官和细胞特异性表达。在胃中，RhBG和RhCG均在胃底和前胃中表达，但在胃窦中不表达。在前胃中，RhBG由所有有核鳞状上皮细胞表达，而RhCG仅在生发层中表达。在眼底，RhBG和RhCG免疫反应存在于酶原细胞，但不是在壁细胞或粘液细胞。此外，酶原细胞RhBG和RhCG表达呈极化，顶端RhCG和基底外侧RhBG免疫反应性。在十二指肠，空肠，回肠和结肠，RhBG和RhCG免疫反应存在于绒毛，但不是在粘液或隐窝细胞。与胃底酶原细胞相似，当顶端RhCG和基底侧RhBG免疫反应存在时，绒毛上皮细胞中RhBG和RhCG的表达呈极化。因此，氨转运蛋白RhBG和RhCG在肠道中表现出细胞特异性、轴向异质性和极化表达，表明它们协同作用以介导胃肠道氨转运。
Ammonia metabolism is important in multiple aspects of gastrointestinal physiology, but the mechanisms of ammonia transport in the gastrointestinal tract remain incompletely defined. The present study examines expression of the ammonia transporter family members Rh B glycoprotein (RhBG) and Rh C glycoprotein ( RhCG) in the mouse gastrointestinal tract. Real-time RT-PCR amplification and immunoblot analysis identified mRNA and protein for both RhBG and RhCG were expressed in stomach, duodenum, jejunum, ileum, and colon. Immunohistochemistry showed organ and cell-specific expression of both RhBG and RhCG. In the stomach, both RhBG and RhCG were expressed in the fundus and forestomach, but not in the antrum. In the forestomach, RhBG was expressed by all nucleated squamous epithelial cells, whereas RhCG was expressed only in the stratum germinativum. In the fundus, RhBG and RhCG immunoreactivity was present in zymogenic cells but not in parietal or mucous cells. Furthermore, zymogenic cell RhBG and RhCG expression was polarized, with apical RhCG and basolateral RhBG immunoreactivity. In the duodenum, jejunum, ileum, and colon, RhBG and RhCG immunoreactivity was present in villous, but not in mucous or crypt cells. Similar to the fundic zymogenic cell, RhBG and RhCG expression in villous epithelial cells was polarized when apical RhCG and basolateral RhBG immunoreactivity was present. Thus the ammonia transporting proteins RhBG and RhCG exhibit cell-specific, axially heterogeneous, and polarized expression in the intestinal tract suggesting they function cooperatively to mediate gastrointestinal tract ammonia transport.