Alveolar epithelial ion and fluid transport - Na transport proteins are expressed by rat alveolar epithelial type I cells
Alveolar epithelial ion and fluid transport - Na transport proteins are expressed by rat alveolar epithelial type I cells
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DOI：
10.1152/ajplung.00130.2000
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发表时间：
2002-04-01
影响因子：
4.9
通讯作者：
Crandall, ED
中科院分区：
文献类型：
--
作者：
Borok, Z;Liebler, JM;Crandall, ED
尽管一个假定的作用，为I型（AT 1）细胞在肺泡上皮运输，具体的钠转运蛋白以前没有被定位到这些细胞。为了评估钠转运蛋白在AT 1细胞中的表达，在全肺和部分纯化的肺泡上皮细胞（AEC）的细胞离心制剂中使用双标记免疫荧光显微镜。在分离的AT 1细胞中评价了Na泵亚单位亚型和大鼠（r）上皮Na通道α亚单位（α-ENaC）的表达，通过其与AT 1细胞特异性抗体标记物（VIIIB 2和/或抗水通道蛋白-5）的免疫反应性以及与AT 2细胞（抗表面活性蛋白A）或白细胞（抗白细胞共同抗原）特异性抗体的反应性缺失进行鉴定。原位评估钠泵α（1）亚单位在AEC中的表达。还通过RT-PCR在高度纯化（类似于95%）的AT 1细胞制备物中评估了Na泵亚单位同种型和α-rENaC表达。用抗α（1）和抗β（1）Na泵亚单位和抗α-rENaC抗体检测分离的AT 1细胞的标记，而不存在与抗α（2）Na泵亚单位抗体的反应性。原位AT 1细胞与抗α（1）Na泵亚单位抗体反应。RT-PCR检测到高纯度AT 1细胞中存在钠泵α（1）-和β（1）-亚基（而非α（2）-亚基）和α-rENaC。这些数据表明，AT 1细胞表达Na泵和Na通道蛋白，支持AT 1细胞在主动跨肺泡上皮Na转运中的作用。
Despite a presumptive role for type I (AT1) cells in alveolar epithelial transport, specific Na transporters have not previously been localized to these cells. To evaluate expression of Na transporters in AT1 cells, double labeling immunofluorescence microscopy was utilized in whole lung and in cytocentrifuged preparations of partially purified alveolar epithelial cells (AEC). Expression of Na pump subunit isoforms and the alpha-subunit of the rat (r) epithelial Na channel (alpha-ENaC) was evaluated in isolated AT1 cells identified by their immunoreactivity with AT1 cell-specific antibody markers (VIIIB2 and/or anti-aquaporin-5) and lack of reactivity with antibodies specific for AT2 cells (anti-surfactant protein A) or leukocytes (anti-leukocyte common antigen). Expression of the Na pump alpha(1)-subunit in AEC was assessed in situ. Na pump subunit isoform and alpha-rENaC expression was also evaluated by RT-PCR in highly purified (similar to95%) AT1 cell preparations. Labeling of isolated AT1 cells with anti-alpha(1) and anti-beta(1) Na pump subunit and anti-alpha-rENaC antibodies was detected, while reactivity with anti-alpha(2) Na pump subunit antibody was absent. AT1 cells in situ were reactive with anti-alpha(1) Na pump subunit antibody. Na pump alpha(1)- and beta(1)- (but not alpha(2)-) subunits and alpha-rENaC were detected in highly purified AT1 cells by RT-PCR. These data demonstrate that AT1 cells express Na pump and Na channel proteins, supporting a role for AT1 cells in active transalveolar epithelial Na transport.