Hidaka K, Mitsuyama T, Furuno T, Tanaka T, Hara N
Research Institute for Diseases of the Chest, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Int Arch Allergy Immunol. 1997 Dec;114(4):336-42. doi: 10.1159/000237691.
Human endothelial cells are injured by the action of leukocytes. We investigated the role of nitric oxide (NO) in the induction of injury to human pulmonary artery endothelial cells. NO has been a putative source of cytotoxic reactive oxygen species in some settings. Incubation of endothelial cells with neutrophils increased the release of lactate dehydrogenase activity and preloaded fura-2 from endothelial cells, indicating that neutrophils induce endothelial cell injury. This effect was augmented by treatment with carboxy-PTIO, which traps NO in the medium, or with L-NAME, an inhibitor of NO synthase. When endothelial cells were incubated with neutrophils stimulated by phorbol myristate acetate, an activator of protein kinase C, endothelial cell damage was further enhanced and the amount of NO in the medium was decreased. Dibutyryl cyclic AMP, a cell-permeable analogue of cyclic AMP, protected against neutrophil-induced endothelial cell injury and increased NO release into the medium. The effects of dibutyryl cyclic AMP were abrogated by treatment with H-89, a potent inhibitor of cyclic AMP-dependent protein kinase. The protective effect on neutrophil-induced endothelial cell injury by dibutyryl cyclic AMP was abolished by addition of carboxy-PTIO or L-NAME. Thus, our studies suggest that NO, presumably released from endothelial cells, protects against endothelial injury by activated neutrophils and the protective effect by cyclic AMP during coculture with activated neutrophils is mediated through the action of NO. However, when monocytes activated by lipopolysaccharide and IFN-gamma were used instead of neutrophils, endothelial cells were likewise injured, but a much higher level of NO was detected and injury was diminished by addition of carboxy-PTIO to the medium. These observations suggest that the high levels of NO released by activated monocytes contribute to endothelial injury, whereas low levels of NO protect endothelial cells against injury by neutrophils.
人类内皮细胞会受到白细胞作用的损伤。我们研究了一氧化氮（NO）在诱导人类肺动脉内皮细胞损伤中的作用。在某些情况下，NO被认为是细胞毒性活性氧的来源。将内皮细胞与中性粒细胞共同孵育会增加乳酸脱氢酶活性的释放以及内皮细胞中预加载的fura-2的释放，这表明中性粒细胞会诱导内皮细胞损伤。用羧基-PTIO（其可捕获培养基中的NO）或一氧化氮合酶抑制剂L-NAME处理可增强这种效应。当内皮细胞与由佛波酯肉豆蔻酸酯乙酸酯（一种蛋白激酶C激活剂）刺激的中性粒细胞共同孵育时，内皮细胞损伤会进一步加剧，且培养基中NO的量会减少。二丁酰环磷酸腺苷（一种可透过细胞的环磷酸腺苷类似物）可保护内皮细胞免受中性粒细胞诱导的损伤，并增加NO向培养基中的释放。用H-89（一种环磷酸腺苷依赖性蛋白激酶的强效抑制剂）处理可消除二丁酰环磷酸腺苷的作用。添加羧基-PTIO或L-NAME可消除二丁酰环磷酸腺苷对中性粒细胞诱导的内皮细胞损伤的保护作用。因此，我们的研究表明，推测从内皮细胞释放的NO可保护内皮细胞免受活化中性粒细胞的损伤，并且在与活化中性粒细胞共培养期间环磷酸腺苷的保护作用是通过NO的作用介导的。然而，当使用由脂多糖和干扰素-γ激活的单核细胞代替中性粒细胞时，内皮细胞同样会受到损伤，但检测到的NO水平要高得多，并且向培养基中添加羧基-PTIO可减轻损伤。这些观察结果表明，活化单核细胞释放的高水平NO会导致内皮细胞损伤，而低水平的NO可保护内皮细胞免受中性粒细胞的损伤。
