Department of Neurosurgery, Taichung Veterans General Hospital, Taichung, Taiwan.
J Cell Biochem. 2010 Apr 15;109(6):1244-53. doi: 10.1002/jcb.22508.
Tumor necrosis factor-alpha (TNF-alpha) is a pleiotropic cytokine produced by activated macrophages. Nitric oxide (NO) is a highly reactive nitrogen radical implicated in inflammatory responses. We investigated the signaling pathway involved in inducible nitric oxide synthase (iNOS) expression and NO production stimulated by TNF-alpha in cultured myoblasts. TNF-alpha stimulation caused iNOS expression and NO production in myoblasts (G7 cells). TNF-alpha-mediated iNOS expression was attenuated by integrin-linked kinase (ILK) inhibitor (KP392) and siRNA. Pretreatment with Akt inhibitor, mammalian target of rapamycin (mTOR) inhibitor (rapamycin), NF-kappaB inhibitor (PDTC), and IkappaB protease inhibitor (TPCK) also inhibited the potentiating action of TNF-alpha. Stimulation of cells with TNF-alpha increased ILK kinase activity. TNF-alpha also increased the Akt and mTOR phosphorylation. TNF-alpha mediated an increase of NF-kappaB-specific DNA-protein complex formation, p65 translocation into nucleus, NF-kappaB-luciferase activity was inhibited by KP392, Akt inhibitor, and rapamycin. Our results suggest that TNF-alpha increased iNOS expression and NO production in myoblasts via the ILK/Akt/mTOR and NF-kappaB signaling pathway.
肿瘤坏死因子-α（TNF-α）是一种由激活的巨噬细胞产生的多功能细胞因子。一氧化氮（NO）是一种在炎症反应中起作用的高反应性氮自由基。我们研究了 TNF-α刺激培养的成肌细胞中诱导型一氧化氮合酶（iNOS）表达和 NO 产生所涉及的信号通路。TNF-α刺激导致成肌细胞（G7 细胞）中 iNOS 的表达和 NO 的产生。整合素连接激酶（ILK）抑制剂（KP392）和 siRNA 减弱了 TNF-α介导的 iNOS 表达。Akt 抑制剂、哺乳动物雷帕霉素靶蛋白（mTOR）抑制剂（雷帕霉素）、NF-κB 抑制剂（PDTC）和 IκB 蛋白酶抑制剂（TPCK）预处理也抑制了 TNF-α的增强作用。用 TNF-α刺激细胞会增加 ILK 激酶活性。TNF-α还增加了 Akt 和 mTOR 的磷酸化。TNF-α介导 NF-κB 特异性 DNA-蛋白复合物形成的增加，p65 易位入核，NF-κB-荧光素酶活性被 KP392、Akt 抑制剂和雷帕霉素抑制。我们的结果表明，TNF-α通过 ILK/Akt/mTOR 和 NF-κB 信号通路增加成肌细胞中 iNOS 的表达和 NO 的产生。
