Xiao Han, Piao Cheng-Shi, Chen Rui-Fei, Zhang You-Yi
Institute of Vascular Medicine, Peking University Third Hospital, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health, Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education and Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing 100191, China.
Sheng Li Xue Bao. 2017 Apr 25;69(2):123-128.
AMP-activated protein kinase (AMPK) activation has been shown to protect against fibrosis. However, the underlying mechanism remains unclear. Here we explored the effect of AMPK activation on transforming growth factor-β1 (TGFβ1) production induced by angiotensin II (AngII) in cardiac fibroblasts and the underlying mechanisms. Adult mouse cardiac fibroblasts were isolated. TGFβ1 and AMPK activity were determined by ELISA and Western blots, respectively. Pretreatment of AMPK activator AICAR inhibited TGFβ1 production induced by AngII in cardiac fibroblasts, which was reversed by AMPK inhibitor compound C. Furthermore, bioinformatics predicted a potential CCAAT/enhancer-binding protein β (C/EBPβ) binding site in the promoter region of the mouse Tgfb1 gene. Luciferase reporter with wild type, but not deleted, C/EBPβ binding sites transfection in mouse embryonic fibroblasts showed increased TGFβ1 transcriptional activity induced by AngII, indicating that C/EBPβ mediates AngII-induced TGFβ1 transcript expression. Pretreatment of AICAR inhibited C/EBPβ expression induced by AngII. In conclusion, AMPK activation inhibited TGFβ1 production induced by AngII in cardiac fibroblasts through targeting C/EBPβ. This finding provides a new mechanism underlying the anti-fibrogenic effects of AMPK activation.
已有研究表明，AMP激活的蛋白激酶（AMPK）激活可预防纤维化。然而，其潜在机制仍不清楚。在此，我们探讨了AMPK激活对心肌成纤维细胞中血管紧张素II（AngII）诱导的转化生长因子-β1（TGFβ1）产生的影响及其潜在机制。分离成年小鼠心肌成纤维细胞。分别通过ELISA和蛋白质印迹法测定TGFβ1和AMPK活性。AMPK激活剂AICAR预处理可抑制心肌成纤维细胞中AngII诱导的TGFβ1产生，而AMPK抑制剂化合物C可逆转这种抑制作用。此外，生物信息学预测在小鼠Tgfb1基因启动子区域存在一个潜在的CCAAT/增强子结合蛋白β（C/EBPβ）结合位点。在小鼠胚胎成纤维细胞中转染具有野生型而非缺失型C/EBPβ结合位点的荧光素酶报告基因，显示AngII诱导的TGFβ1转录活性增加，表明C/EBPβ介导AngII诱导的TGFβ1转录表达。AICAR预处理可抑制AngII诱导的C/EBPβ表达。总之，AMPK激活通过靶向C/EBPβ抑制心肌成纤维细胞中AngII诱导的TGFβ1产生。这一发现为AMPK激活的抗纤维化作用提供了一种新机制。
