Insulin-like growth factor-I induces reactive oxygen species production and cell migration through Nox4 and Rac1 in vascular smooth muscle cells
Insulin-like growth factor-I induces reactive oxygen species production and cell migration through Nox4 and Rac1 in vascular smooth muscle cells
复制标题
胰岛素样生长因子-I 通过 Nox4 和 Rac1 诱导血管平滑肌细胞中活性氧的产生和细胞迁移
DOI：
10.1093/cvr/cvn173
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发表时间：
2008-11-01
影响因子：
10.8
通讯作者：
Fang, Jing
中科院分区：
文献类型：
--
作者：
Meng, Dan;Lv, Dan-Dan;Fang, Jing
目的 我们之前表明，胰岛素样生长因子-I (IGF-I) 通过产生活性氧 (ROS) 诱导血管平滑肌细胞 (VSMC) 增殖。然而，IGF-I 如何诱导 ROS 尚不清楚。本研究的目的是探讨 IGF-I 诱导 VSMC 产生 ROS 的机制。 方法结果 采用逆转录 PCR、实时 PCR、免疫印迹和共聚焦显微图像分析来测定蛋白表达、小 Rho-GTPase Rac1 激活和 ROS 产生。通过 siRNA 技术抑制 NADPH 氧化酶 4 (Nox4) 或 Rac1。使用显性失活形式的 Rac1 (N17Rac1) 质粒实现对 Rac1 活性的抑制。这项工作使用了来自 Sprague-Dawley 大鼠胸主动脉的 VSMC。IGF-I 增强了大鼠 VSMC 中 ROS 的产生。 IGF-I增加Nox4的蛋白水平，但对其mRNA水平影响不大。 IGF-I 诱导 Rac1 的激活。 Nox4 的敲低或 Rac1 的失活都会损害 IGF-I 诱导的 ROS。 Nox4 的过表达增加了 NADPH 氧化酶活性，但不受 Rac1 失活的影响。 Rac1 的过度表达和敲低都不影响 Nox4 的表达。 Nox4 的敲低并不影响 IGF-I 诱导的 Rac1 激活。 IGF-I 增加基质金属蛋白酶 (MMP)-2 和 9 活性并促进 VSMC 迁移，而 Nox4 敲低和 Rac1 失活可抑制这种迁移。结论我们的结果表明，Nox4 和 Rac1 介导 IGF-I 诱导的 VSMC 中 ROS 产生和细胞迁移，并且 Nox4 不受 Rac1 调节。
Aims We showed previously that insulin-like growth factor-I (IGF-I)-induced vascular smooth muscle cells (VSMCs) proliferation through the production of reactive oxygen species (ROS). However, how IGF-I-induced ROS was unknown. The aim of this study is to investigate the mechanisms by which IGF-I induces ROS production in VSMCs.Methods results Reverse transcription-PCR, real-time PCR, immunoblotting, and confocal microscopic image analysis were employed to determine protein expression, small Rho-GTPase Rac1 activation, and ROS production. Inhibition of NADPH oxidase 4 (Nox4) or Rac1 was performed by means of siRNA technology. Inhibition of Rac1 activity was accomplished using dominant-negative form of Rac1 (N17Rac1) plasmid. VSMCs from Sprague-Dawley rat thoracic aortas were used in this work.IGF-I enhanced ROS production in rat VSMCs. IGF-I increased the protein level of Nox4 but had little effect on its mRNA level. IGF-I induced the activation of Rac1. Either knockdown of Nox4 or inactivation of Rac1 impaired IGF-I-induced ROS. Over-expression of Nox4 increased NADPH oxidase activity, which was not influenced by inactivation of Rac1. Neither over-expression nor knockdown of Rac1 influenced Nox4 expression. Knockdown of Nox4 did not affect IGF-I-induced activation of Rac1. IGF-I increased matrix metalloproteinase (MMP)-2 and 9 activity and promoted VSMC migration, which was inhibited by knockdown of Nox4 and inactivation of Rac1.Conclusion Our results suggest that Nox4 and Rac1 mediate IGF-I-induced ROS production and cell migration in VSMCs and that Nox4 is not regulated by Rac1.