Liu Xin-Hua, Zhang Qiu-Yan, Pan Li-Long, Liu Si-Yu, Xu Peng, Luo Xiao-Ling, Zou Si-Li, Xin Hong, Qu Le-Feng, Zhu Yi-Zhun
Shanghai Key Laboratory of Bioactive Small Molecules, Department of Pharmacology, School of Pharmacy, Fudan University, 826, Zhangheng Road, Pudong New District, Shanghai 201203, China.
Department of Vascular Surgery, Changzheng Hospital, Second Military Medical University, 415 Fengyang Road, Shanghai 200003, China.
Free Radic Biol Med. 2016 May;94:174-84. doi: 10.1016/j.freeradbiomed.2016.02.031. Epub 2016 Mar 3.
Transforming growth factor-β (TGF-β)/Smad signaling has been implicated in connective tissue growth factor (CTGF) expression in vascular smooth muscle cells (VSMC). Reactive oxygen species (ROS) are involved in activation of TGF-β/Smad signaling. However, detailed mechanisms underlying the process remain unclear. In present study, we demonstrated TGF-β1 strongly induced CTGF expression, Smad3 activation, NADPH oxidase 4 (Nox4) expression and increased ROS production in primary rat VSMC in vitro. NADPH oxidases inhibitor diphenylene iodonium (DPI) eliminated TGF-β1-induced CTGF expression and ROS generation. In addition, small-interfering RNA (siRNA) silencing of Smad3 or Nox4 significantly suppressed TGF-β1-mediated CTGF expression in VSMC. Furthermore, Nox4 silencing or inhibition eliminated TGF-β1-induced Smad3 activation and interaction between Nox4 and Smad3. In vivo studies further identified a positive correlation of Nox4 levels with Smad3 activation and CTGF expression in atherosclerotic arteries of patients and animal models. These data established that a novel mechanistic link of Nox4-dependent activation of Smad3 to increased TGF-β1-induced CTGF in the process of vascular remodeling, which suggested a new potential pathway for therapeutic interventions.
转化生长因子-β（TGF-β）/Smad信号通路与血管平滑肌细胞（VSMC）中结缔组织生长因子（CTGF）的表达有关。活性氧（ROS）参与TGF-β/Smad信号通路的激活。然而，这一过程背后的详细机制仍不清楚。在本研究中，我们证明TGF-β1在体外可强烈诱导原代大鼠VSMC中CTGF的表达、Smad3的激活、NADPH氧化酶4（Nox4）的表达并增加ROS的产生。NADPH氧化酶抑制剂二苯基碘鎓（DPI）消除了TGF-β1诱导的CTGF表达和ROS生成。此外，小干扰RNA（siRNA）沉默Smad3或Nox4可显著抑制VSMC中TGF-β1介导的CTGF表达。此外，Nox4沉默或抑制消除了TGF-β1诱导地Smad3激活以及Nox4与Smad3之间的相互作用。体内研究进一步证实，在患者和动物模型的动脉粥样硬化动脉中，Nox4水平与Smad3激活和CTGF表达呈正相关。这些数据表明，在血管重塑过程中，Nox4依赖的Smad3激活与TGF-β1诱导的CTGF增加之间存在一种新的机制联系，这为治疗干预提供了一条新的潜在途径。
