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[The effect of miR-124 on homocysteine-induced atherosclerosis via promoter region DNA methylation in ApoE−/− mice] [Article in Chinese]

ZHAO Li, JIAO Yun, YANG An-Ning, KONG Fan-Qi, LIU Xian-Mei, YANG Xiao-Ling, JIANG Yi-Deng

College of Laboratory Medicine； College of Preclinical Medicine； Department of Infectious Disease of General Hospital, Ningxia Medical University, Yinchuan 750004, China

Abstract

The aim of the present study is to explore the role of miR-124 and its promoter region DNA methylation in homocysteine (Hcy)-induced atherosclerosis. ApoE−/− mice were fed with hypermethionine diet for 16 weeks to duplicate hyperhomocysteinemia model. Meanwhile, a normal control group (C57BL/6J mice fed with normal diet, N-control) and a model control group (ApoE−/− mice fed with normal diet, A-control) were set. The degree of atherosclerosis was observed by HE and oil red O staining. Automatic biochemical analyzer was used to detect the serum levels of Hcy. Foam cell model was duplicated and oil red O staining was used to confirm whether the model was successfully established. And foam cells were stimulated with 0, 50, 100, 200, 500 μmol/L Hcy and 50 μmol/L Hcy + 10 μmol/L AZC respectively. Real-time quantitative PCR (RT-qPCR) was used to detect the expressions of miR-124 in mice aorta and foam cells; Nested landing methylation specific PCR (nMS-PCR) was used to detect the levels of miR-124 promoter DNA methylation in mice aorta and foam cells. Meanwhile, the effects of DNA methylation inhibitor AZC on miR-124 expression were observed at the cellular level. The effect of miR-124 promoter DNA methylation status on lipid accumulation in foam cells was observed by oil red O staining. The results showed that compared with model control group, the serum levels of Hcy in high methionine group were significantly increased (P < 0.01) and developed aortic atherosclerotic plaque, the expression of miR-124 was markedly decreased (P < 0.01), while the levels of miR-124 promoter DNA methylation were significantly increased (P < 0.01). Given different levels of Hcy, the expression of miR-124 in foam cells was decreased, while the levels of miR-124 promoter DNA methylation were increased in a dose-dependent manner (P < 0.05, P < 0.01). AZC reversed the results of mentioned indices as above markedly (P < 0.05). Downregulation of miR-124 may play a role in Hcy-induced atherosclerosis and its promoter DNA methylation status may be an important mechanism in this process.

Key words: Homocysteine; ApoE−;/−; mice; foam cells; miR-124; DNA methylation

Received: 2014-10-20　　Accepted: 2014-12-02

Corresponding author: 姜怡邓　　E-mail: jwcjyd@163.com

Citing This Article：

ZHAO Li, JIAO Yun, YANG An-Ning, KONG Fan-Qi, LIU Xian-Mei, YANG Xiao-Ling, JIANG Yi-Deng. [The effect of miR-124 on homocysteine-induced atherosclerosis via promoter region DNA methylation in ApoE−/− mice] [Article in Chinese]. Acta Physiol Sin 2015; 67 (2): 207-213 (in Chinese with English abstract).