Department of Pathology, Beijing Luhe Hospital,Capital Medical University, Beijing, 101100, China.
Yan Jing Medical College, Capital Medical University, Beijing, 101300, China.
Biochem Biophys Res Commun. 2019 Nov 19;519(4):734-739. doi: 10.1016/j.bbrc.2019.09.062. Epub 2019 Sep 19.
Omi/HtrA2 is a pro-apoptotic protein, increased mRNA and protein levels of Omi/HtrA2 in aging myocardium facilitates apoptosis and affects mitochondrial homeostasis. Our previous study found that p53 can bind to the Omi/HtrA2 promoter. The purpose of this study was to determine whether p53 participates in regulating the expression of Omi/HtrA2 in aging myocardium.
we used Western blot to detect the expression of Omi/HtrA2 and p53 nucleoprotein, and then found that both of them were elevated in aging heart. Furthermore, we also observed the increased binding of p53 to Omi/HtrA2 promoter by chromatin immunoprecipitation. To initially explore the regulation mechanism of Omi/HtrA2, plasmid transfection and RNA interference in NIH3T3 cells were used to upregulate or knock down p53, respectively. The mRNA and protein levels of Omi/HtrA2 were increased with the overexpression of p53 by real-time PCR and Western blot, and Omi/HtrA2 promoter activity enhanced after transfected with pcDNA3.1-p53. The result from RNA interference was quite the contrary.Our study demonstrated that the binding ability of p53 to Omi/HtrA2 promoter was increased in aging myocardium, and increased p53 promoted the mRNA and protein levels of Omi/HtrA2 by enhancing the promoter activity of Omi/HtrA2.
p53 acts as a transcriptional factor that induces Omi/HtrA2 expression in aged cardiomyocytes.These results provide a new way to explore the mechanism of increased Omi/HtrA2 in the aging process of heart.
Omi/HtrA2 是一种促凋亡蛋白，衰老心肌中 Omi/HtrA2 的 mRNA 和蛋白水平增加促进细胞凋亡，并影响线粒体的动态平衡。我们之前的研究发现 p53 可以与 Omi/HtrA2 启动子结合。本研究旨在确定 p53 是否参与调节衰老心肌中 Omi/HtrA2 的表达。
我们使用 Western blot 检测 Omi/HtrA2 和 p53 核蛋白的表达，然后发现它们在衰老心脏中均升高。此外，我们还通过染色质免疫沉淀观察到 p53 与 Omi/HtrA2 启动子的结合增加。为了初步探讨 Omi/HtrA2 的调节机制，我们在 NIH3T3 细胞中使用质粒转染和 RNA 干扰分别上调或敲低 p53。实时 PCR 和 Western blot 结果显示，p53 的过表达增加了 Omi/HtrA2 的 mRNA 和蛋白水平，并且 pcDNA3.1-p53 转染后 Omi/HtrA2 启动子活性增强。RNA 干扰的结果则恰恰相反。我们的研究表明，衰老心肌中 p53 与 Omi/HtrA2 启动子的结合能力增加，并且增加的 p53 通过增强 Omi/HtrA2 启动子活性促进 Omi/HtrA2 的 mRNA 和蛋白水平。
p53 作为一种转录因子，在衰老的心肌细胞中诱导 Omi/HtrA2 的表达。这些结果为探索心脏衰老过程中 Omi/HtrA2 增加的机制提供了新的途径。
