FGF7通过上调SOD2抑制心肌成纤维细胞中纤维化相关基因的表达

FGF7 inhibits expression of cardiac fibrosis-related genes by up-regu⁃lating SOD2 expression in cardiac fibroblasts

目的:研究成纤维细胞生长因子7(FGF7)调控心肌纤维化相关基因表达的作用机制。方法:利用mRNA表达谱芯片检测心衰患者心肌组织与健康对照心肌组织以及重组FGF7腺病毒感染小鼠心肌成纤维细胞(mCFs)和正常对照mCFs中差异表达的基因。血管紧张素Ⅱ(AngⅡ)诱导mCFs建立心肌纤维化的细胞模型。流式细胞术检测过表达FGF7对mCFs细胞周期的影响。利用重组FGF7腺病毒感染mCFs,RT-qPCR及Western blot检测FGF7、Ⅰ型胶原α1链(Col1a1)、Ⅲ型胶原α1链(Col3a1)和肌动蛋白α2(Acta2)等纤维化相关基因的表达,并检测蛋白激酶B(PKB/Akt)和腺苷酸活化蛋白激酶(AMPK)的活化情况。用siRNA沉默mCFs中超氧化物歧化酶2(SOD2)的表达或用AMPK抑制剂compound C抑制mCFs中AMPK的活性后,检测过表达FGF7的mCFs中心肌纤维化相关基因表达的变化。结果:心衰患者心肌组织及AngⅡ诱导的mCFs中FGF7的表达显著降低(P<0.05)。过表达FGF7不影响mCFs的细胞周期,但可降低mCFs中Col1a1、Col3a1和Acta2的表达(P<0.05)。过表达FGF7的mCFs中SOD2表达和磷酸化AMPK水平增加(P<0.05),但磷酸化Akt水平无显著变化(P>0.05)。沉默SOD2可逆转FGF7抑制mCFs中纤维化相关基因表达的作用,而compound C可减弱FGF7上调SOD2表达和抑制纤维化相关基因表达的作用。结论:FGF7通过激活AMPK来增加SOD2表达,从而发挥抑制mCFs中纤维化相关基因表达的作用。

AIM:To investigate the effect of fibroblast growth factor 7(FGF7)on expression of cardiac fibro⁃sis-related genes and the mechanism involved.METHODS:The mRNA expression of differentially expressed genes in the myocardium of heart failure patients and healthy controls,as well as in mouse cardiac fibroblasts(mCFs)with over-ex⁃pression of FGF7 and normal control mCFs,was performed using mRNA microarray technique.A cell model of angioten⁃sinⅡ(AngⅡ)-induced cardiac fibrosis was established in the mCFs.The change of cell cycle distribution in the mCFs was detected by flow cytometry.Over-expression of FGF7 was achieved by recombinant FGF7 adenovirus in mCFs,and the expression of fibrosis-related genes,including collagen typeⅠα1 chain(Col1a1),collagen typeⅢα1 chain(Col3a1)and actinα2(Acta2),in the mCFs was determined by RT-qPCR and Western blot.Activation of protein kinase B(PKB/Akt)and AMP-activated protein kinase(AMPK)signaling pathway was also detected in the mCFs with over-ex⁃pression of FGF7.Small interfering RNA(siRNA)was used to silence the expression of superoxide dismutase 2(SOD2),and compound C,an AMPK inhibitor,was used to block AMPK activity in the mCFs.The effects of SOD2 knockdown and AMPK inactivation on the expression of fibrosis-related genes were investigated in the mCFs with over-expression of FGF7.RESULTS:FGF7 expression was significantly down-regulated in the patients with heart failure,and in the mCFs treated with AngⅡ.Over-expression of FGF7 inhibited the expression of Col1a1,Col3a1 and Acta2 in the mCFs,and no effect on cell cycle distribution of mCFs was observed.Increased SOD2 expression and phosphorylated AMPK level,but not the phosphorylated Akt level,were observed in the mCFs with FGF7 over-expression.Knock-down of SOD2 reversed the ef⁃fect of FGF7 on the expression of fibrosis-related genes in the mCFS.Moreover,compound C attenuated the up-regulation of SOD2 and the inhibition of fibrosis-related gene expression by FGF7 in the mCFs.CONCLUSION:FGF7 inhibits car⁃diac fibrosis-related gene expression via up-regulating AMPK-dependent SOD2 expression in mCFs.