BRD4基因对TGF-β1诱导的心肌细胞凋亡和p38MAPK信号通路的影响

doi:10.13481/j.1671-587x.20190419

摘要/Abstract

摘要： 目的：探讨溴结构域蛋白4（BRD4）基因对转化生长因子β1（TGF-β1）诱导的心肌细胞凋亡的影响，阐明其可能的作用机制。方法：将H9c2细胞分为空白对照组、si-CN组（转染阴性对照siRNA）和si-BRD4组（转染特异性siRNA），采用Western blotting法检测各组细胞中BRD4蛋白表达水平。大鼠心肌H9c2细胞随机分为对照组、TGF-β1组（20μg·L^-1TGF-β1处理细胞24 h）、si-NC+TGF-β1组（转染阴性对照的siRNA后，使用TGF-β1处理细胞24 h）和si-BRD4+TGF-β1组（转染BRD4特异性siRNA后，使用TGF-β1处理细胞24h）。MTT法检测各组细胞增殖活性，Annexin Ⅴ-FITC/PI双染法检测细胞凋亡率，Western blotting法检测各组细胞中BRD4、B淋巴细胞瘤-2（Bcl-2）、Bcl-2相关X蛋白（Bax）、活化的含半胱氨酸的天冬氨酸蛋白水解酶3（Cleaved caspase3）、P38和磷酸化P38（p-P38）蛋白表达水平。结果：与空白对照组比较，si-BRD4组H9c2细胞中BRD4蛋白表达水平明显降低（P<0.01）。与对照组比较，TGF-β1组细胞增殖活性明显降低（P<0.05），细胞凋亡率明显升高（P<0.05），Bcl-2蛋白表达水平明显降低（P<0.01），Bax、Cleaved caspase3和p-P38蛋白表达水平均明显升高（P<0.01）；与TGF-β1组比较，si-BRD4+TGF-β1组细胞增殖活性明显升高（P<0.05），细胞凋亡率明显降低（P<0.05），Bcl-2蛋白表达水平明显升高（P<0.05），Bax、Cleaved caspase3和p-P38蛋白表达水平均明显降低（P<0.05）。结论：抑制BRD4基因表达可减弱TGF-β1诱导的心肌细胞凋亡，其机制可能与抑制P38丝裂原活化蛋白激酶（MAPK）信号通路有关。

关键词: 心肌细胞, 溴结构域蛋白4, 转化生长因子β1, P38丝裂原活化蛋白激酶信号通路

Abstract: Objective:To investigate the effect of bromodomain-containing protein 4(BRD4) gene on the apoptosis of cardiomyocytes induced by transforming growth factor-β1 (TGF-β1), and to clarify its possible mechanism. Methods:The H9c2 cells were randomly divided into blank control group,si-CN group (transfected with negative control siRNA),and si-BRD4 group (transfected with specific siRNA).The expression levels of BRD4 protein in the cells in various groups were detected by Western blotting method.The H9c2 cells were randomly divided into control group, TGF-β1 group (transfected with 20μg·L^-1TGF-β1 for 24 h), si-NC+TGF-β1 group (treated with TGF-β1 for 24 h after transfected with negative control siRNA) and si-BRD4+TGF-β1 group (treated with TGF-β1 for 24 h after transfected with BRD4 specific siRNA).The cell proliferation activity was measured by MTT assay, and the apoptotic rate of cells was detected by Annexin Ⅴ-FITC/PI double staining. Western blotting method was used to detect the expressions of BRD4, Bcl-2, Bax, Cleaved caspase 3, P38, and p-P38 proteins. Results:Compared with blank control group, the expression level of BRD4 protein in the H9c2 cells in si-BRD4 group was significantly decreased (P<0.01).Compared with control group, the cell proferation activity and the Bcl-2 protein expression level in TGF-β1 group were significantly decreased(P<0.01); the apoptotic rate, and the expression levels of Bax, Cleaved caspase3, and p-p38 proteins were significantly increased (P<0.01).Compared with TGF-β1 group, the cell prdiferation activity and the expression level of Bcl-2 protein in si-BRD4+TGF-β1 group were significantly increased (P<0.05), while the apoptotic rate and the expression levels of Bax, Cleaved caspase3, and p-p38 proteins were significantly reduced(P<0.05). Conclusion:Inhibition of BRD4 gene expression can attenuate the apoptosis of cardiomyocytes induced by TGF-β1, which may be related to the inhibition of p38MAPK signaling pathway.

Key words: cardiomyocyte, bromo domain protein 4, transforming growth factor 1, p38MAPK signaling pathway

中图分类号:

杨东伟, 桂雨农. BRD4基因对TGF-β1诱导的心肌细胞凋亡和p38MAPK信号通路的影响[J]. 吉林大学学报(医学版), 2019, 45(04): 855-860.

YANG Dongwei, GUI Yunong. Effects of BRD4 gene on apoptosis and p38MAPK signaling pathway of cardiomyocytes induced by TGF-β1[J]. Journal of Jilin University(Medicine Edition), 2019, 45(04): 855-860.

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