Murota S, Fujita H, Wakabayashi Y, Morita I
Department of Physiological Chemistry, Graduate School, Tokyo Medical and Dental University, Japan.
Keio J Med. 1996 Sep;45(3):207-11; discussion 211-2. doi: 10.2302/kjm.45.207.
Addition of PMA (phorbol myristate acetate)-stimulated neutrophils to an endothelial cell monolayer caused a significant increase in the intracellular peroxide level of the endothelial cells after 15 minutes and endothelial cell injury after 5 hours. Both the early and the late events were abolished in the presence of specific antibodies against CD (cluster of differentiation) 11a, CD11b, CD18 and ICAM (intercellular adhesion molecule) 1, but not CD11c. These antibodies affected neither the production of active oxygen species by the neutrophils nor the rate of adhesion of neutrophils to endothelial cells. Pretreatment of endothelial cells with allopurinol caused significant inhibition of both the early and the late events, suggesting that the binding of adhesion molecules may trigger the activation of XO (xanthine oxidase) of endothelial cells, and have the cells produce more hydrogen peroxide and ferrous ions, followed by producing more hydrogen peroxide. The hydrogen peroxide produced by endothelial cells themselves and by neutrophils may be converted to hydroxyl radicals by ferrous ions, which may cause lethal cell damage. Examination of XO activity in endothelial cells showed that the enzyme activity increased double within 15 minutes after the addition of PMA activated neutrophils. Monoclonal antibodies against CD11a and CD18 significantly inhibited the increased conversion of XD (xanthine dehydrogenase) to XO induced by PMA-activated neutrophils. Moreover, tyrosine kinase inhibitors also inhibited the increased conversion of XD to XO. These results indicate that the adhesion of activated neutrophils to endothelial cells via CD11a/CD18-ICAM-1 is involved in the conversion of XD to XO in endothelial cells, which results in endothelial cell injury.
将经佛波醇肉豆蔻酸酯乙酸酯（PMA）刺激的中性粒细胞添加到内皮细胞单层中，15分钟后内皮细胞内过氧化物水平显著升高，5小时后出现内皮细胞损伤。在存在抗分化簇（CD）11a、CD11b、CD18和细胞间黏附分子（ICAM）1的特异性抗体时，早期和晚期事件均被消除，但抗CD11c抗体则无此作用。这些抗体既不影响中性粒细胞产生活性氧的能力，也不影响中性粒细胞与内皮细胞的黏附速率。用别嘌呤醇预处理内皮细胞可显著抑制早期和晚期事件，这表明黏附分子的结合可能触发内皮细胞黄嘌呤氧化酶（XO）的激活，使细胞产生更多过氧化氢和亚铁离子，进而产生更多过氧化氢。内皮细胞自身和中性粒细胞产生的过氧化氢可能被亚铁离子转化为羟基自由基，从而导致致命的细胞损伤。对内皮细胞中XO活性的检测表明，在添加经PMA激活的中性粒细胞后15分钟内，该酶活性增加了一倍。抗CD11a和CD18的单克隆抗体显著抑制了由PMA激活的中性粒细胞诱导的黄嘌呤脱氢酶（XD）向XO的转化增加。此外，酪氨酸激酶抑制剂也抑制了XD向XO的转化增加。这些结果表明，活化的中性粒细胞通过CD11a/CD18-ICAM-1与内皮细胞的黏附参与了内皮细胞中XD向XO的转化，从而导致内皮细胞损伤。
