Masubuchi T, Koyama S, Sato E, Takamizawa A, Kubo K, Sekiguchi M, Nagai S, Izumi T
The First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Japan.
Am J Pathol. 1998 Dec;153(6):1903-12. doi: 10.1016/S0002-9440(10)65704-5.
Inflammatory cells accumulate within the lungs of cigarette smokers. Current concepts suggest that these cells can induce protease-antiprotease and/or oxidant-antioxidant imbalance(s), which may damage the normal lung alveolar and interstitial structures. Because type II pneumocytes line the alveolar space, and because the inflammatory cells migrate and reside at the alveolus, we postulated that the type II pneumocytes might release chemotactic activity for neutrophils and monocytes in response to smoke extract. To test this hypothesis, A549 cells were cultured and the supernatant fluids were evaluated for the neutrophil and monocyte chemotactic activity (NCA and MCA) by a blind-well chamber technique. A549 cells released NCA and MCA in response to smoke extract in a dose- and time-dependent manner (P < 0.05). Checkerboard analysis showed that the activity was chemotactic. Partial characterization of NCA and MCA revealed that the activity was partly heat labile, trypsin sensitive, and ethyl acetate extractable. Lipoxygenase inhibitors and cycloheximide inhibited the release of NCA and MCA. Molecular sieve column chromatography showed multiple peaks for both NCA and MCA. NCA was inhibited by anti-human-interleukin (IL)-8 antibody, granulocyte colony-stimulating factor (G-CSF) antibody, or leukotriene (LT)B4 receptor antagonist. Monocyte chemoattractant protein (MCP)-1 antibody or LTB4 receptor antagonist inhibited MCA. Immunoreactive IL-8, G-CSF, MCP-1, and LTB4 significantly increased in the supernatant fluids in response to smoke extract. These data suggest that the type II pneumocytes may release NCA and MCA and modulate the inflammatory cell recruitment into the lung.
炎症细胞在吸烟者的肺部积聚。目前的观点认为，这些细胞可诱导蛋白酶-抗蛋白酶和/或氧化剂-抗氧化剂失衡，这可能会损害正常的肺泡和间质结构。由于Ⅱ型肺泡上皮细胞排列在肺泡腔内，且炎症细胞迁移并驻留在肺泡，我们推测Ⅱ型肺泡上皮细胞可能会对烟雾提取物产生反应，释放对中性粒细胞和单核细胞的趋化活性。为了验证这一假设，培养了A549细胞，并通过盲孔室技术评估了上清液对中性粒细胞和单核细胞的趋化活性（NCA和MCA）。A549细胞对烟雾提取物以剂量和时间依赖性方式释放NCA和MCA（P<0.05）。棋盘分析表明该活性具有趋化性。对NCA和MCA的部分特性分析显示，该活性部分对热不稳定、对胰蛋白酶敏感且可被乙酸乙酯提取。脂氧合酶抑制剂和环己酰亚胺抑制NCA和MCA的释放。分子筛柱色谱显示NCA和MCA均有多个峰。NCA被抗人白细胞介素（IL）-8抗体、粒细胞集落刺激因子（G-CSF）抗体或白三烯（LT）B4受体拮抗剂抑制。单核细胞趋化蛋白（MCP）-1抗体或LTB4受体拮抗剂抑制MCA。响应烟雾提取物，上清液中免疫反应性IL-8、G-CSF、MCP-1和LTB4显著增加。这些数据表明，Ⅱ型肺泡上皮细胞可能释放NCA和MCA，并调节炎症细胞向肺内的募集。
