Comparison of albumin uptake in rat alveolar type II and type i-like epithelial cells in primary culture
Comparison of albumin uptake in rat alveolar type II and type i-like epithelial cells in primary culture
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DOI：
10.1007/s11095-007-9426-x
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发表时间：
2008-04-01
影响因子：
3.7
通讯作者：
Takano, Mikihisa
中科院分区：
文献类型：
--
作者：
Ikehata, Mika;Yumoto, Ryoko;Takano, Mikihisa
目的.阐明并比较原代培养的肺泡II型和I型样上皮细胞摄取白蛋白的活性和机制。将从大鼠肺分离的II型上皮细胞以5x 106个细胞/35 mm培养皿培养2天或以2x 106个细胞/35 mm培养皿培养6天。培养2 d的细胞呈立方状II型上皮，细胞内有板层小体，培养6 d的细胞呈鳞状I型上皮。这些形态特征与标记基因mRNA表达模式的变化相一致。两种细胞中的FITC-白蛋白摄取均具有温度依赖性，并受到代谢抑制剂和巴弗洛霉素A的抑制（1）。II型细胞的摄取率远高于I型样细胞。在这两种细胞中，FITC-白蛋白摄取被网格蛋白介导的内吞抑制剂抑制，但不被小窝介导的内吞inhibitors.These研究结果表明，肺泡衬里液中的白蛋白通过网格蛋白介导的内吞内化到II型和I型上皮细胞中，并且II型细胞中的白蛋白摄取速率高于I型细胞。
Purpose. To elucidate and compare the activity and mechanism of albumin uptake in primary cultured alveolar type II and type I-like epithelial cells.Materials and methods. Type II epithelial cells isolated from rat lungs were cultured for 2 days at 5x10(6) cells/35-mm dish or for 6 days at 2x10(6) cells/35-mm dish. The mRNA expression of marker genes and FITC-albumin uptake were examined.The cells cultured for 2 days exhibited cuboidal type II epithelial morphology with lamellar bodies inside the cells, while the cells cultured for 6 days exhibited squamous type I epithelial morphology. These morphological characteristics were consistent with the changes in mRNA expression pattern of marker genes. FITC-albumin uptake in both cells was temperature-dependent and was inhibited by metabolic inhibitors and bafilomycin A(1). The rate of uptake was much higher in type II cells than type I-like cells. In both cells, FITC-albumin uptake was inhibited by clathrin mediated-endocytosis inhibitors, but not by caveolae mediated-endocytosis inhibitors.These findings indicate that albumin in alveolar lining fluid is internalized into type II and type I epithelial cells via clathrin-mediated endocytosis, and the rate of albumin uptake is higher in type II cells than type I cells.