微小RNA-155通过靶向缺氧诱导因子1α调控心肌纤维化

MicroRNA-155 regulates myocardial fibrosis-related gene expression by targeting hypoxia-inducible factor 1α

目的探讨微小RNA(miR)-155对心肌成纤维细胞(cardiac fibroblasts,CFs)中纤维化相关基因表达的作用及其机制。方法实验分为对照组、血管紧张素(Ang)Ⅱ组、 Scramble组、 miR-155mimic组、 AngⅡ+Scramble组、AngⅡ+miR-155 mimic组、AngⅡ+HIF-1αsiRNA组。AngⅡ刺激原代分离培养的小鼠CFs,模拟心肌纤维化过程中CFs活化过程,采用PCR及Western blot检测各组miR-155、1型胶原(Col 1)、3型胶原(Col 3)、α-平滑肌肌动蛋白(α-SMA)的表达;采用双荧光素酶报告基因实验检测miR-155与缺氧诱导因子(HIF)-1α3’端非编码区(3’-UTR)的结合作用。结果 AngⅡ刺激可显著促进小鼠CFs中纤维化相关基因的表达,同时降低miR-155的水平(P<0.05);过表达miR-155可显著降低AngⅡ诱导的小鼠CFs中纤维化相关基因的表达(P<0.05);HIF-1α受到了miR-155的负性调控,并能同miR-155结合;miR-155 mimic和HIF-1αsiRNA能一致性的降低AngⅡ诱导的小鼠CFs中纤维化相关蛋白的表达。结论 miR-155能抑制AngⅡ诱导的CFs纤维化,进而抑制心肌纤维化;HIF-1α是miR-155的靶基因,并介导了miR-155发挥抑制AngⅡ诱导的CFs纤维化的过程。

AIM To investigate the effect and mechanism of microRNA-155(miR-155) on the expressions of fibrosis-related genes in cardiac fibroblasts(CFs).METHODS The mice were divided into 7 groups:control group,AngII group,Scramble group,miR-155 mimic group,AngII + Scramble group,AngII + miR-155 mimic group,and AngII + HIF-1α siRNA group.Angiotensin II(AngII)stimulated mouse CFs to simulate the activation of CFs during myocardial fibrosis.PCR and Western blot were used to detect the expressions of miR-155,type 1 collagen(Col 1),type 3 collagen(Col 3) and α-smooth muscle actin(α-SMA).Combination of miR-155 and 3’-untranslated region of hypoxia-inducible factor 1α(HIF-1α) was detected by dual luciferase reporter assay.RESULTS AngII stimulation significantly promoted the expression of fibrosis-related genes in mouse CFs and decreased the level of miR-155.Over-expression of miR-155 significantly decreased the expression of fibrosis-related genes in mouse CFs induced by AngII.HIF-1α was negatively regulated by miR-155 and could bind to miR-155.miR-155 mimic and HIF-1α siRNA consistently reduced the expressions of fibrosis-associated proteins in mouse CFs.CONCLUSION miR-155 can inhibit myocardial fibrosis.HIF-1α is a target gene of miR-155 and is involved in the process of miR-155 in inhibiting the expressions of CFs-related proteins and inhibiting myocardial fibrosis.