Nishihira J, Ishibashi T, Takeichi N, Sakamoto W, Nakamura M
Department of Biochemistry, School of Medicine, Hokkaido University, Sapporo, Japan.
Biochim Biophys Acta. 1994 Feb 17;1220(3):286-90. doi: 10.1016/0167-4889(94)90150-3.
Combined stimulation, by superoxide ions generated by the xanthine-xanthine oxidase reaction, and platelet-activating factor (PAF), induced cell differentiation of rat monocytic leukemia cells (c-WRT-LR) to macrophage-like mature cells. Monitoring of cytochrome c reduction revealed that PAF stimulation induced the release of superoxide ions from c-WRT-LR. To further investigate the effect of superoxide ions in the autocrine or paracrine mechanism in cell differentiation, molecular species of the oxygen radicals under PAF stimulation were examined using the EPR spin trap, 5,5'-dimethyl-1-pyrroline N-oxide (DMPO). PAF and/or phorbol myristate acetate caused the formation of EPR spectra, a combination of DMPO/.OOH and DMPO/.OH. Since both spectra were diminished in the presence of superoxide dismutase, it was concluded that DMPO/.OH was derived from superoxide ions. Mannitol and catalase suppressed cell differentiation induced by combined stimulation with PAF and oxygen radicals generated by the xanthine-xanthine oxidase reaction. Taken together, these results suggest that hydroxyl radicals generated by Fenton reaction from H2O2 may be involved in the mechanism of cell differentiation in rat monocytic leukemia cells.
黄嘌呤 - 黄嘌呤氧化酶反应产生的超氧离子与血小板活化因子（PAF）联合刺激，可诱导大鼠单核细胞白血病细胞（c - WRT - LR）分化为巨噬细胞样成熟细胞。细胞色素c还原监测显示，PAF刺激可诱导c - WRT - LR释放超氧离子。为进一步研究超氧离子在细胞分化的自分泌或旁分泌机制中的作用，使用电子顺磁共振自旋捕获剂5,5'-二甲基 - 1 - 吡咯啉N - 氧化物（DMPO）检测了PAF刺激下氧自由基的分子种类。PAF和/或佛波醇肉豆蔻酸酯乙酸盐导致了电子顺磁共振光谱的形成，即DMPO/.OOH和DMPO/.OH的组合。由于在超氧化物歧化酶存在下这两种光谱都减弱了，因此得出结论，DMPO/.OH源自超氧离子。甘露醇和过氧化氢酶抑制了PAF与黄嘌呤 - 黄嘌呤氧化酶反应产生的氧自由基联合刺激所诱导的细胞分化。综上所述，这些结果表明，H2O2通过芬顿反应产生的羟基自由基可能参与大鼠单核细胞白血病细胞的细胞分化机制。
