Yoshida Hideyuki, Kwon A-Hon, Habara Kozo, Yamada Masanori, Kaibori Masaki, Kamiyama Yasuo, Nishizawa Mikio, Ito Seiji, Okumura Tadayoshi
Department of Surgery, Kansai Medical University, Moriguchi, Osaka, Japan.
Shock. 2008 Dec;30(6):734-9. doi: 10.1097/SHK.0b013e318173ea0b.
Edaravone, a free radical scavenger, plays crucial roles in the prevention of injuries to the brain, heart, and liver. Our in vivo study indicated that edaravone prevented endotoxin-induced liver injury through inhibition of NO production in addition to reductions in oxidative products and proinflammatory cytokine induction. Studies were performed to determine whether edaravone directly influences the induction of iNOS in murine RAW264 macrophages as a substitute for Kupffer cells (resident macrophages) in the liver. RAW264 cells were treated with LPS (1 microg/mL) in the presence or absence of edaravone. NO production, iNOS induction, and its related signaling were analyzed. Edaravone (0.5 - 5 mM) decreased the production of NO stimulated by LPS in time- and dose-dependent manners, and these concentrations of edaravone had no cytotoxic effects. Edaravone decreased the levels of iNOS protein and mRNA. Transfection experiments with iNOS promoter-luciferase constructs revealed that edaravone inhibited the activities of both iNOS promoter transactivation and iNOS mRNA stabilization. However, edaravone did not have any effects on I kappaB alpha degradation or nuclear factor-kappaB activation. In contrast, edaravone markedly suppressed the LPS-stimulated expression of iNOS antisense-transcript, which stabilizes iNOS mRNA by interacting with its 3'-untranslated region and RNA-binding proteins. Edaravone may inhibit the induction of iNOS gene expression at the steps of its promoter transactivation in a nuclear factor-kappaB-independent manner and mRNA stabilization in RAW264 cells.
依达拉奉是一种自由基清除剂，在预防脑、心脏和肝脏损伤方面发挥着关键作用。我们的体内研究表明，依达拉奉除了能减少氧化产物和促炎细胞因子的诱导外，还通过抑制一氧化氮（NO）的产生来预防内毒素诱导的肝损伤。我们进行了多项研究，以确定依达拉奉是否直接影响小鼠RAW264巨噬细胞中诱导型一氧化氮合酶（iNOS）的表达，以此作为肝脏中库普弗细胞（驻留巨噬细胞）的替代模型。RAW264细胞在有或没有依达拉奉的情况下用脂多糖（LPS，1微克/毫升）进行处理。分析了NO的产生、iNOS的诱导及其相关信号传导。依达拉奉（0.5 - 5毫摩尔）以时间和剂量依赖的方式降低了LPS刺激产生的NO，并且这些浓度的依达拉奉没有细胞毒性作用。依达拉奉降低了iNOS蛋白和mRNA的水平。用iNOS启动子 - 荧光素酶构建体进行的转染实验表明，依达拉奉抑制了iNOS启动子反式激活和iNOS mRNA稳定性的活性。然而，依达拉奉对IκBα降解或核因子κB激活没有任何影响。相反，依达拉奉显著抑制了LPS刺激的iNOS反义转录物的表达，该反义转录物通过与其3'非翻译区和RNA结合蛋白相互作用来稳定iNOS mRNA。依达拉奉可能在RAW264细胞中以不依赖核因子κB的方式在其启动子反式激活步骤以及mRNA稳定性方面抑制iNOS基因表达的诱导。
