Roles of SP-A, SP-B, and SP-C in modulation of lipid uptake by pulmonary epithelial cells in vitro.
Roles of SP-A, SP-B, and SP-C in modulation of lipid uptake by pulmonary epithelial cells in vitro.
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DOI：
10.1152/ajplung.1996.270.1.l69
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
A. Horowitz;B. Moussavian;J. Whitsett
中科院分区：
文献类型：
--
作者：
A. Horowitz;B. Moussavian;J. Whitsett
在大鼠II型上皮细胞和具有肺泡细胞特征的肺腺癌细胞系MLE-12细胞中研究了表面活性蛋白（SP）-A、SP-B和SP-C对荧光标记的脂质囊泡的结合和内吞作用的影响。将SP-C掺入脂质囊泡中，在4 ℃下显著刺激与细胞膜的结合，在37 ℃下刺激脂质的内吞作用。SP-C增强MLE-12细胞、II型细胞和NIH 3 T3细胞的脂质摄取。SP-B刺激MLE-12细胞的脂质摄取，但程度较低。SP-B降低了SP-C刺激的脂质摄取量，SP-A不增加MLE-12细胞或II型细胞对脂质的内吞作用，但在SP-A存在下观察到与细胞表面相关的脂质聚集体。肺中活性表面活性物质的维持可通过选择性吸收和降解SP-A和SP-B中耗尽的表面活性物质亚组分来实现。
The effects of the surfactant proteins (SP)-A, SP-B, and SP-C on binding and endocytosis of fluorescently labeled lipid vesicles were studied in rat type II epithelial cells and in MLE-12 cells, a pulmonary adenocarcinoma cell line with alveolar cell characteristics. Incorporation of SP-C in lipid vesicles markedly stimulated binding to the cell membrane at 4 degrees C and endocytosis of lipids at 37 degrees C. SP-C enhanced lipid uptake in MLE-12 cells, type II cells, and NIH 3T3 cells. SP-B stimulated lipid uptake in MLE-12 cells, but to a lesser degree. SP-B decreased the amount of lipid uptake stimulated by SP-C, SP-A did not increase endocytosis of lipids by MLE-12 cells or type II cells, but aggregates of lipid were observed associated with the cell surface in the presence of SP-A. Maintenance of active surfactant in the lung may be achieved through the selective uptake and degradation of surfactant subfractions depleted in SP-A and SP-B.