Ji Yuan-yuan, Wang Zhi-dong, Liu Jun-tian, Liu Na
Department of Pharmacology, Xi'an Jiaotong University School of Medicine, Xi'an 710061, China.
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi. 2008 Nov;24(11):1037-9.
To investigate the effects of angiotensin II (Ang II) on mRNA and protein expressions of toll-like receptor 4 (TLR4) and myeloperoxidase (MPO) activity in RAW264.7 cells, and explore its pro-inflammatory and pro-atherosclerotic mechanisms.
Murine RAW264.7 cells were cultured and stimulated with different concentrations (1, 10, 100 and 1,000 nmol/L) of Ang II or LPS (100 microg/L) for 24 h. TLR4 mRNA levels were analyzed by RT-PCR, and TLR4 protein expression was measured by Western blot. MPO activity in the supernatant was assayed with colorimetry. Then, the cells were pretreated with TLR4 blocker (1 and 5 mg/L) for 1 h prior to stimulation with 100 nmol/L Ang II for 24 h, and MPO activity in the supernatant was detected.
Ang II increased mRNA and protein expressions of TLR4 in RAW264.7 cells in concentration-dependent manner (P<0.01), and LPS also induced mRNA and protein expressions of TLR4 in RAW264.7 cells (P<0.01). In addition, Ang II concentration-dependently elevated MPO activity in RAW264.7 cells (P<0.01), and LPS also enhanced MPO activity of RAW264.7 cells (P<0.01), but the TLR4 blocker significantly antagonized the effect of Ang II on MPO activity (P<0.01).
Ang II upregulates TLR4 expressions, and induces MPO secretion via TLR4 in RAW264.7 cells, which mediate the pro-inflammatory effect of Ang II to contribute formation and development of atherosclerosis.
研究血管紧张素II（Ang II）对RAW264.7细胞中Toll样受体4（TLR4）的mRNA和蛋白表达以及髓过氧化物酶（MPO）活性的影响，并探讨其促炎和促动脉粥样硬化机制。
培养小鼠RAW264.7细胞，用不同浓度（1、10、100和1000 nmol/L）的Ang II或脂多糖（LPS，100 μg/L）刺激24小时。通过逆转录聚合酶链反应（RT-PCR）分析TLR4 mRNA水平，用蛋白质印迹法检测TLR4蛋白表达。用比色法测定上清液中的MPO活性。然后，在用100 nmol/L Ang II刺激24小时之前，先用TLR4阻断剂（1和5 mg/L）预处理细胞1小时，检测上清液中的MPO活性。
Ang II以浓度依赖性方式增加RAW264.7细胞中TLR4的mRNA和蛋白表达（P<0.01），LPS也诱导RAW264.7细胞中TLR4的mRNA和蛋白表达（P<0.01）。此外，Ang II以浓度依赖性方式提高RAW264.7细胞中的MPO活性（P<0.01），LPS也增强RAW264.7细胞的MPO活性（P<0.01），但TLR4阻断剂显著拮抗Ang II对MPO活性的影响（P<0.01）。
Ang II上调RAW264.7细胞中TLR4的表达，并通过TLR4诱导MPO分泌，介导Ang II的促炎作用，促进动脉粥样硬化的形成和发展。
