Acid stimulation reduces bactericidal activity of surface liquid in cultured human airway epithelial cells
Acid stimulation reduces bactericidal activity of surface liquid in cultured human airway epithelial cells
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DOI：
10.1165/ajrcmb.26.1.4425
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发表时间：
2002-01-01
影响因子：
6.4
通讯作者：
Sasaki, H
中科院分区：
文献类型：
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作者：
Nakayama, K;Jia, YX;Sasaki, H
为了检测中等酸度（pH 3.0-5.0）的酸暴露对气道表面液体（ASL）杀菌活性的影响，在用磷酸盐缓冲盐水（PBS）调节至pH 3.0、4.0或5.0处理后24小时，通过洗涤人气管上皮细胞原代培养物的表面收集ASL。在所有ASL中，杀菌活性对钠浓度敏感。将大肠埃希菌（500菌落形成单位[CFU]）在ASL中孵育，并检查存活细菌的数量。在pH3.0 -5.0的酸暴露条件下，ASL中存活的细菌数量显著高于对照ASL。ASL对500 CFU大肠杆菌的最小抑菌稀释比为1.5 × 10 - 6;大肠杆菌也通过微量稀释测定进行了检查。根据该测定，在pH 3.0的酸挑战下ASL的杀菌活性小于对照ASL的一半。逆转录-聚合酶链反应和蛋白质印迹分析表明，在pH 3.0-5.0的酸暴露显着降低人β-防御素（HBD）-1的mRNA和蛋白质的产生。与此相反，酸暴露没有改变HBD-2和β-肌动蛋白mRNA的mRNA和蛋白质的产生。这些结果表明，酸暴露，即使是中等酸度，可能会抑制杀菌分子的生产，包括HBD-1，在气道上皮细胞。酸暴露可能降低ASL在人气道上皮细胞中的杀菌活性，并可能增加气道对细菌感染的易感性。
To examine the effects of acid exposure with moderate acidity (pH 3.0-5.0) on bactericidal activity of airway surface liquid (ASL), ASL was collected by washing the surface of primary cultures of human tracheal epithelia[ cells 24 h after treatment with phosphate-buffered saline (PBS) adjusted to a pH of 3.0, 4.0, or 5.0. In all ASL, bactericidal activity was sensitive to sodium concentration. Escherichia coli (500 colony forming units [CFU]) was incubated in ASL, and the number of surviving bacteria was examined. The number of surviving bacteria in ASL from cultured cells with acid exposure at pH 3.0-5.0 was significantly higher than that in control ASL. The minimum inhibitory dilution ratio of ASL against 500 CFU of E. coli was also examined by microdilution assays. According to this assay, the bactericidal activity in ASL with acid challenge at a pH of 3.0 was less than half of that in control ASL. Reverse transcription-polymerase chain reaction and Western blot analysis showed that the production of mRNA and protein of human beta-defensin (HBD)-1 were significantly decreased by acid exposure at pH 3.0-5.0. In contrast, acid exposure did not change the production of mRNA and protein of HBD-2 and beta-actin mRNA. These results indicate that acid exposure, even with moderate acidity, may inhibit the production of bactericidal molecules, including HBD-1, in airway epithelial cells. Acid exposure may reduce bactericidal activity of ASL in human airway epithelial cells and may increase susceptibility of the airway to bacterial infection.