Koyama S, Rennard S I, Claassen L, Robbins R A
First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Japan.
Am J Pathol. 1995 May;146(5):1207-19.
Escherichia coli endotoxin (0.1 to 1000 micrograms/ml) stimulated the release of neutrophil chemotactic activity (P < 0.001) and induced bronchial epithelial cell (BEC) cytotoxicity assessed by lactate dehydrogenase release (P < 0.001). Endotoxin (100 micrograms/ml) inhibited BEC accumulation (P < 0.001). In the present study, we investigated the role of proteolytic activity of BECs per se in response to endotoxin. Several structurally and functionally different antiproteases, alpha 1 protease inhibitor, soybean trypsin inhibitor, two chloromethyl ketone derivatives (N-tosyl-L-lysine chloromethyl ketone and methoxysuccinyl-Ala-Ala-Pro-Val chloromethyl ketone), and L-658,758, a neutrophil elastase inhibitor, attenuated the release of neutrophil chemotactic activity and lactate dehydrogenase (P < 0.01). alpha 1-Protease inhibitor and N-tosyl-L-lysine chloromethyl ketone attenuated the inhibition of BEC accumulation by endotoxin (P < 0.001). The proteolytic enzyme activity measured by synthetic substrates revealed that endotoxin significantly augmented the serine proteolytic activity in the cell layers. Culture supernatant fluids and cell lysates of BECs in the presence of endotoxin solubilized 14C-labeled casein. These data suggest that responses of BECs to endotoxin may involve activation of cellular proteolytic activity.
大肠杆菌内毒素（0.1至1000微克/毫升）刺激了中性粒细胞趋化活性的释放（P<0.001），并通过乳酸脱氢酶释放评估诱导了支气管上皮细胞（BEC）的细胞毒性（P<0.001）。内毒素（100微克/毫升）抑制了BEC的聚集（P<0.001）。在本研究中，我们调查了BEC自身的蛋白水解活性在内毒素反应中的作用。几种结构和功能不同的抗蛋白酶，α1蛋白酶抑制剂、大豆胰蛋白酶抑制剂、两种氯甲基酮衍生物（N-甲苯磺酰-L-赖氨酸氯甲基酮和甲氧基琥珀酰-Ala-Ala-Pro-Val氯甲基酮）以及中性粒细胞弹性蛋白酶抑制剂L-658,758，减弱了中性粒细胞趋化活性和乳酸脱氢酶的释放（P<0.01）。α1-蛋白酶抑制剂和N-甲苯磺酰-L-赖氨酸氯甲基酮减弱了内毒素对BEC聚集的抑制作用（P<0.001）。通过合成底物测量的蛋白水解酶活性显示，内毒素显著增强了细胞层中的丝氨酸蛋白水解活性。在内毒素存在的情况下，BEC的培养上清液和细胞裂解物溶解了14C标记的酪蛋白。这些数据表明，BEC对内毒素的反应可能涉及细胞蛋白水解活性的激活。
