Localization of endothelial NOS at the basal microtubule membrane in ciliated epithelium of rat lung
Localization of endothelial NOS at the basal microtubule membrane in ciliated epithelium of rat lung
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DOI：
10.1177/44.5.8627003
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发表时间：
1996-05-01
影响因子：
3.2
通讯作者：
Johns, RA
中科院分区：
文献类型：
--
作者：
Xue, C;Botkin, SJ;Johns, RA
一氧化氮（Nitric oxide，NO）是一种重要的细胞信使分子，在肺气道中内源性生成。在培养的肺上皮细胞中，已发现了三种独立的NO合成酶（NOS）基因，分别代表脑型NOS（bNOS）、诱导型NOS（inducible NOS，iNOS）和内皮型NOS（endothelial NOS，eNOS）。虽然体内研究表明bNOS和iNOS表达并定位于支气管上皮细胞的胞浆中，但eNOS的表达和定位仍有待确定。因此，我们采用了eNOS单克隆抗体，其免疫特异性通过Western印迹和预吸附免疫组织化学检测免疫染色大鼠肺从胎儿到成人。结果表明，eNOS免疫反应在生后2h内开始在肺上皮细胞内出现，6h后（生后8h），NOS免疫反应集中在纤毛上皮细胞表面，这种染色模式在第1天、第1周、第2周及成年大鼠肺内均出现。通过电子显微镜，eNOS免疫反应性被证实纤毛上皮内，并被证明是与纤毛的基底微管膜。无纤毛细胞未染色，II型上皮细胞也含有eNOS免疫反应性，其主要与粗面内质网和游离核糖体相关。而肺内巨噬细胞缺乏eNOS的免疫反应性。本研究表明，eNOS在大鼠生后支气管纤毛上皮中有表达。eNOS在纤毛微管基底膜的定位表明，eNOS可能参与上皮纤毛的功能，与以前的生理研究一致。
Nitric oxide (NO), an important cell messenger molecule, is formed endogenously in the lung airway, Three individual genes of NO synthase (NOS), which represent brain NOS (bNOS), inducible NOS (iNOS), and endothelial NOS (eNOS), have been reported in the cultured lung epithelium. Although studies in vivo showed that bNOS and iNOS were expressed and localized in the cytoplasm of bronchial epithelium, the expression and localization of eNOS remains to be determined. Therefore, we employed an eNOS monoclonal antibody whose immunospecificity was tested by both Western blot and preadsorption immunohistochemistry to immunostain rat lungs from fetus to adult. The results showed that eNOS immunoreactivity began to appear in the lung epithelium within 2 hr after birth, Six hours later (8 hr after birth), the NOS immunoreaction was concentrated near the surface of the ciliated epithelial cells, This staining pattern appeared in lungs at Day 1, Week 1, Week 2, and in adult rats. By electron microscopy, eNOS immunoreactivity was confirmed within ciliated epithelium and was shown to be associated with the basal microtubule membrane of the cilia. Nonciliated cells were not stained, Type II epithelial cells also contain eNOS immunoreactivity, which is primarily associated with rough endoplasmic reticulum and free ribosomes. However, macrophages in the lungs lacked eNOS immunoreactivity, This study demonstrated that eNOS was postnatally expressed in rat bronchial ciliated epithelium. The localization of eNOS at the basal membrane of ciliary microtubules suggests that eNOS may be involved in the function of epithelial cilia, consistent with previous physiological studies.