Effects of metalloproteinase inhibitors on leukotriene A4 hydrolase in human airway epithelial cells.
Effects of metalloproteinase inhibitors on leukotriene A4 hydrolase in human airway epithelial cells.
复制标题
金属蛋白酶抑制剂对人气道上皮细胞白三烯 A4 水解酶的影响。
DOI：
10.1016/0006-2952(95)00210-q
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发表时间：
1995
影响因子：
5.8
通讯作者：
Bigby,TD
中科院分区：
文献类型：
--
作者：
Baker,JR;Kylstra,TA;Bigby,TD
人中性粒细胞白三烯A4(LTA4)水解酶是一种含锌金属蛋白酶，具有氨肽酶活性，可被一些金属蛋白酶抑制剂抑制。人气道上皮细胞还含有 LTA4 水解酶，该酶具有一些新特性，表明这种酶可能在功能和结构上是独特的。因此，我们质疑上皮酶是否也可以被金属蛋白酶抑制剂抑制。研究了完整或破坏的转化人气道上皮细胞。在所检测的金属蛋白酶抑制剂中，只有卡托普利、贝司汀和福辛普利拉对受损上皮细胞中的 LTA4 水解酶具有明显的抑制活性。卡托普利、贝他汀和福辛普利拉的浓度抑制曲线显示，对于破坏的细胞 LTA4 水解酶活性，IC50 值分别为 430 μM、7 μM 和 1 mM。与其对中性粒细胞的影响相反，1,10-O-菲咯啉对破坏的上皮细胞水解酶活性没有显着影响，并且当该活性部分纯化时（179 倍），仅产生最小的影响。在完整细胞中用卡托普利、贝他汀和 1,10-O-菲咯啉检查的 LTA4 水解酶浓度抑制曲线显示，IC50 值分别为 63、70 和 920 μM。破坏的上皮细胞中的氨肽酶活性被amastatin、bestatin和1,10-O-菲咯啉抑制（IC50值分别为500 nM、1 μM和17 μM），但在最高测试浓度（10 mM）的卡托普利则不被抑制。这些发现与之前的中性粒细胞研究形成鲜明对比。当用卡托普利处理后用 A23187 刺激中性粒细胞时，LTB4 的跨细胞合成比白三烯 B4 (LTB4) 的直接合成受到更有效的抑制（43.8 ± 2.5 vs 18.5 ± 4.7%；N = 8，P < 0.02）。我们得出结论，人气道上皮细胞的 LTA4 水解酶活性受到一些金属蛋白酶抑制剂的抑制，但抑制谱与中性粒细胞酶的抑制谱不同。这些数据提供了额外的信息，表明上皮细胞中的 LTA4 水解酶是一种新型酶，与中性粒细胞中发现的酶不同。
Human neutrophil leukotriene A4(LTA4) hydrolase is a zinc-containing metalloproteinase with aminopeptidase activity and can be inhibited by some metalloproteinase inhibitors. Human airway epithelial cells also contain an LTA4hydrolase enzyme that has some novel properties, suggesting that this enzyme may be functionally and structurally unique. Thus, we questioned whether the epithelial enzyme could also be inhibited by metalloproteinase inhibitors. Transformed human airway epithelial cells were studied either intact or disrupted. Of the metalloproteinase inhibitors examined, only captopril, bestatin, and fosinoprilat had appreciable inhibitory activity for LTA4hydrolase in disrupted epithelial cells. Concentration-inhibition curves to captopril, bestatin, and fosinoprilat revealed ic50values of 430 μM, 7 μM, and 1 mM, respectively, for disrupted-cell LTA4hydrolase activity. In contrast to its effects on neutrophils, 1,10-O-phenanthroline had no significant effect on disrupted epithelial cell hydrolase activity and had only minimal effects when this activity was partially purified (179-fold). LTA4hydrolase concentration-inhibition curves examined in intact cells with captopril, bestatin, and 1,10-O-phenanthroline revealed ic50values of 63, 70, and 920 μM, respectively. Aminopeptidase activity in disrupted epithelial cells was inhibited by amastatin, bestatin, and 1,10-O-phenanthroline (ic50values of 500 nM, 1 μM, and 17 μM, respectively), but not by captopril at the highest concentration tested, 10 mM. These findings are in contrast to prior studies in neutrophils. When neutrophils were stimulated with A23187 after treatment with captopril, transcellular synthesis of LTB4was inhibited more effectively than direct synthesis of leukotriene B4(LTB4) (43.8 ± 2.5 vs 18.5 ± 4.7%; N = 8, P < 0.02). We conclude that LTA4hydrolase activity of human airway epithelial cells is inhibited by some metalloproteinase inhibitors, but that the profile of inhibition is distinct from that for the neutrophil enzyme. These data provide additional information that LTA4hydrolase in the epithelial cell is a novel enzyme, distinct from that found in the neutrophil.