Graduate School of Third Military Medical University, Chongqing 400038, China.
Atherosclerosis. 2012 Dec;225(2):304-14. doi: 10.1016/j.atherosclerosis.2012.08.015. Epub 2012 Sep 13.
Phenotypic modulation of adventitial fibroblasts (AFs) plays an important role in the pathogenesis of proliferative vascular diseases. The current study aimed to identify the role of cellular repressor E1A-stimulated genes (CREG), a critical mediator in the maintenance of vascular homeostasis, in AF phenotypic modulation and adventitial remodeling.
Using in situ double-immunofluorescence staining, we ascertained that CREG expression was significantly down-regulated in the adventitia after vascular injury, and its expression pattern was conversely correlated with the expression of smooth muscle α-actin (α-SMA), a marker for differentiation of AFs into myofibroblasts. In vitro data confirmed the association of CREG in angiotensin II (Ang II)-induced AF differentiation. Additionally, overexpression of CREG attenuated Ang II-induced α-SMA expression in AFs. CREGoverexpressing AFs showed decreased levels of proliferation on days 2-5 following stimulation by Ang II compared with controls, with changes in the cell cycle profile as shown by BrdU incorporation assay and fluorescence activated cell sorting analysis. Moreover, wound healing assay and transwell migration model demonstrated that upregulation of CREG expression inhibited Ang II-induced AF migration. We found that CREG-mediated its counterbalancing effects in Ang II-induced phenotypic modulation, proliferation and migration by inhibition of the p38MAPK signaling pathway, validated by pharmacological blockade of p38MAPK with SB 203580 and by overexpression of p38MAPK with transfectants expressing constitutively active p38αMAPK.
Our findings suggest that CREG is a novel AF phenotypic modulator in a p38MAPK-dependent manner. Modulating CREG on the local vascular wall may become a new therapeutic target against proliferative vascular diseases.
外膜成纤维细胞（AFs）的表型调节在增殖性血管疾病的发病机制中起着重要作用。本研究旨在确定细胞抑制剂 E1A 刺激基因（CREG）在 AF 表型调节和外膜重塑中的作用，CREG 是维持血管稳态的关键介质。
通过原位双重免疫荧光染色，我们确定血管损伤后外膜中 CREG 的表达显著下调，其表达模式与平滑肌α-肌动蛋白（α-SMA）的表达相反，α-SMA 是 AF 分化为肌成纤维细胞的标志物。体外数据证实了 CREG 与血管紧张素 II（Ang II）诱导的 AF 分化有关。此外，过表达 CREG 可减弱 Ang II 诱导的 AF 中α-SMA 的表达。与对照组相比，在 Ang II 刺激后的第 2-5 天，过表达 CREG 的 AF 的增殖水平降低，通过 BrdU 掺入测定和荧光激活细胞分选分析显示细胞周期谱发生变化。此外，划痕愈合试验和 Transwell 迁移模型表明，上调 CREG 表达可抑制 Ang II 诱导的 AF 迁移。我们发现 CREG 通过抑制 p38MAPK 信号通路来介导其在 Ang II 诱导的表型调节、增殖和迁移中的拮抗作用，该通路通过 p38MAPK 的药理学阻断剂 SB 203580 和通过转染表达组成型激活 p38αMAPK 的转染体进行验证。
我们的研究结果表明，CREG 是一种新型的 p38MAPK 依赖性 AF 表型调节剂。调节局部血管壁上的 CREG 可能成为治疗增殖性血管疾病的新靶点。
