Zhang Wei Jian, Frei Balz
Linus Pauling Institute, Oregon State University, Corvallis, OR, USA.
Free Radic Biol Med. 2003 Mar 15;34(6):674-82. doi: 10.1016/s0891-5849(02)01375-8.
Endothelial adhesion molecule expression and monocyte recruitment are causal events in human atherosclerosis, and are believed to be caused, in part, by oxidative stress. Because redox-active transition metal ions, such as iron and copper, play an essential role in the generation of free radicals and the initiation and propagation of lipid peroxidation, we hypothesized that transition metal ions may also be involved in endothelial activation. Therefore, we investigated the effects of the intracellular iron-chelator, desferrioxamine (DFO), and the intracellular copper-chelator, neocuproine (NC), on TNFalpha-induced expression of adhesion molecules in human aortic endothelial cells (HAEC). Treatment of HAEC with DFO (0.01-0.1 mM) or NC (0.1 and 0.5 mM) time- and dose-dependently inhibited TNFalpha-induced protein expression of E-selectin, vascular cell adhesion molecule-1 (VCAM-1), and intercellular adhesion molecule-1 (ICAM-1). In contrast, iron-saturated DFO and the extracellular copper chelator, bathocuproinedisulfonic acid, had no effect on adhesion molecule expression. DFO and NC also dose-dependently inhibited TNFalpha-induced upregulation of adhesion molecule mRNA levels. Furthermore, treatment of HAEC with 0.5 mM DFO or NC completely inhibited TNFalpha-induced activation of the transcription factor, specificity protein-1 (SP-1), but only partially inhibited or did not affect activation of other transcription factors known to regulate adhesion molecule expression, i.e., nuclear factor kappaB (NFkappaB), activator protein-1 (AP-1), and interferon regulatory factor-1 (IRF-1). Finally, inhibition of endothelial nitric oxide synthase with N-nitro-L-arginine methylester (0.5 mM) did not attenuate the inhibitory effects of the metal ion chelators on adhesion molecule expression. Our data suggest that intracellular, but not extracellular, transition metal ions mediate inflammatory cytokine-induced SP-1 activation and adhesion molecule expression in endothelial cells.
内皮黏附分子表达和单核细胞募集是人类动脉粥样硬化中的因果事件，并且部分被认为是由氧化应激引起的。由于具有氧化还原活性的过渡金属离子，如铁和铜，在自由基的产生以及脂质过氧化的起始和传播中起重要作用，我们推测过渡金属离子也可能参与内皮激活。因此，我们研究了细胞内铁螯合剂去铁胺（DFO）和细胞内铜螯合剂新铜试剂（NC）对人主动脉内皮细胞（HAEC）中肿瘤坏死因子α（TNFα）诱导的黏附分子表达的影响。用DFO（0.01 - 0.1 mM）或NC（0.1和0.5 mM）处理HAEC，可时间和剂量依赖性地抑制TNFα诱导的E选择素、血管细胞黏附分子-1（VCAM-1）和细胞间黏附分子-1（ICAM-1）的蛋白表达。相反，铁饱和的DFO和细胞外铜螯合剂bathocuproinedisulfonic acid对黏附分子表达没有影响。DFO和NC也剂量依赖性地抑制TNFα诱导的黏附分子mRNA水平上调。此外，用0.5 mM DFO或NC处理HAEC完全抑制了TNFα诱导的转录因子特异性蛋白-1（SP-1）的激活，但仅部分抑制或不影响已知调节黏附分子表达的其他转录因子的激活，即核因子κB（NFκB）、激活蛋白-1（AP-1）和干扰素调节因子-1（IRF-1）。最后，用N-硝基-L-精氨酸甲酯（0.5 mM）抑制内皮型一氧化氮合酶并没有减弱金属离子螯合剂对黏附分子表达的抑制作用。我们的数据表明，细胞内而非细胞外的过渡金属离子介导了炎症细胞因子诱导的内皮细胞中SP-1激活和黏附分子表达。
