Choi Shinkyu, Park Seonghee, Liang Guo Hua, Kim Ji Aee, Suh Suk Hyo
Department of Physiology and Medical Research Center, School of Medicine, Ewha Womans University, Seoul, Republic of Korea.
Cell Physiol Biochem. 2010;25(2-3):233-40. doi: 10.1159/000276557. Epub 2010 Jan 12.
We examined the mechanism through which lysophosphatidylcholine (LPC) induces endothelial nitric oxide (eNOS) downregulation. Human umbilical vein endothelial cells (HUVECs) were treated with LPC (50-150 microM) for 0.5-2 h or the reactive oxygen species (ROS) donors, xanthine/xanthine oxidase (X/XO), 1,4-hydroquinone (HQ) or tert-butylhydroperoxide (TBHP) for 2 h. Protein levels of eNOS, superoxide dismutase1 (SOD1), catalase, and phospho-extracellular signal regulated kinase 1/2 (pERK 1/2) were assessed using immunoblotting. LPC treatment reduced SOD1 levels but increased catalase levels. The superoxide donors X/XO and HQ showed similar effects. The hydroperoxide donor TBHP increased SOD1 levels but did not change catalase levels. LPC concentration- and time-dependently decreased eNOS levels, but this effect was blocked by antioxidants and SOD and potentiated by the SOD1 inhibitor, ammonium tetrathiomolybdate. LPC and X/XO inhibited ERK1/2 phosphorylation, whereas TBHP stimulated phosphorylation. Taken together, these data indicate that LPC induces superoxide overload in HUVECs via SOD1 inhibition and downregulates phospho-ERK1/2 and eNOS levels.
我们研究了溶血磷脂酰胆碱（LPC）诱导内皮型一氧化氮合酶（eNOS）下调的机制。用人脐静脉内皮细胞（HUVECs）分别用LPC（50 - 150微摩尔）处理0.5 - 2小时，或用活性氧（ROS）供体黄嘌呤/黄嘌呤氧化酶（X/XO）、1,4 - 对苯二酚（HQ）或叔丁基过氧化氢（TBHP）处理2小时。使用免疫印迹法评估eNOS、超氧化物歧化酶1（SOD1）、过氧化氢酶和磷酸化细胞外信号调节激酶1/2（pERK 1/2）的蛋白水平。LPC处理降低了SOD1水平，但增加了过氧化氢酶水平。超氧化物供体X/XO和HQ显示出类似的效果。氢过氧化物供体TBHP增加了SOD1水平，但未改变过氧化氢酶水平。LPC浓度和时间依赖性地降低eNOS水平，但这种作用被抗氧化剂和SOD阻断，并被SOD1抑制剂四硫代钼酸铵增强。LPC和X/XO抑制ERK1/2磷酸化，而TBHP刺激磷酸化。综上所述，这些数据表明LPC通过抑制SOD1诱导HUVECs中超氧化物过载，并下调磷酸化ERK1/2和eNOS水平。
