Homocysteine induces blood vessel global hypomethylation mediated by LOX-1.
Homocysteine induces blood vessel global hypomethylation mediated by LOX-1.
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DOI：
10.4238/2014.may.16.2
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发表时间：
2014-05
期刊：
影响因子：
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通讯作者：
X. L. Yang;J. Tian;Y. Liang;C. J. Ma;A. Yang;J. Wang;S. C. Ma;Y. Cheng;X. Hua;Y. D. Jiang
中科院分区：
文献类型：
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作者：
X. L. Yang;J. Tian;Y. Liang;C. J. Ma;A. Yang;J. Wang;S. C. Ma;Y. Cheng;X. Hua;Y. D. Jiang
同型半胱氨酸（Hcy）通过参与甲硫氨酸循环而成为动脉粥样硬化的独立危险因素。在这项研究中，我们的目的是确定在Hcy诱导的动脉粥样硬化载脂蛋白-E-缺陷（ApoE-/-）小鼠的血管整体甲基化率，并探讨这种变化在内皮细胞的可能机制。将ApoE-/-小鼠分为高脂血症（HLP）组、高同型半胱氨酸血症（HHcy）组和HHcy +叶酸+维生素B12（HHcy+FA+VB）组。制备野生型C57 BL/6 J小鼠作为对照。采用全自动生化分析仪和高效液相色谱法测定血清总同型半胱氨酸（Hcy）、血脂、S-腺苷蛋氨酸（SAM）和S-腺苷同型半胱氨酸（SAH）含量。使用巢式甲基化特异性聚合酶链反应（nMS-PCR）检测血管中B1重复元件的甲基化。内皮细胞（EC）用Hcy或加入FA和VB预处理。采用定量PCR、Western blot和nMS-PCR检测血凝素样氧化低密度脂蛋白受体-1（LOX-1）的表达。HHcy组HLP和HHcy均较重。HHcy组SAM和SAH含量较其他各组均升高。HHcy组B1重复序列甲基化水平（0.5050 ± 0.0182）显著高于HLP组（0.5158 ± 0.0163）和对照组（0.5589 ± 0.0236）。100 μM Hcy刺激后，内皮细胞LOX-1 mRNA和蛋白表达增加（0.2877 ± 0.0341，0.6090 ± 0.0547），甲基化表达减少（0.5527 ± 0.0148）。总之，Hcy诱导的动脉粥样硬化与诱导的血管低甲基化状态密切相关，这一过程部分由LOX-1 DNA甲基化介导。
Homocysteine (Hcy) is an independent risk factor of atherosclerosis through its involvement with the methionine cycle. In this study, we aimed to determine the blood vessel global methylation rate in Hcy-induced atherosclerosis in apolipoprotein-E-deficient (ApoE-/-) mice, and to explore the possible mechanism of this change in endothelial cells. ApoE-/- mice were divided into a hyperlipidemia (HLP) group, a hyperhomocysteinemia (HHcy) group, and an HHcy + folate + vitamin B12 (HHcy+FA+VB) group. Wild-type C57BL/6J mice were prepared as controls. Total Hcy, lipids, S-adenosylmethionine (SAM), and S-adenosylhomocysteine (SAH) contents in serum were measured with an automatic biochemistry analyzer and high-performance liquid chromatography. Methylation of B1 repetitive elements in blood vessels was tested using nested methylation-specific-polymerase chain reaction (nMS-PCR). Endothelial cells (ECs) were pretreated with Hcy or by adding FA and VB. Lectin-like oxidized LDL receptor-1 (LOX-1) expressions were determined by quantitative PCR, Western blot, and nMS-PCR. The HHcy group displayed severe HLP and HHcy. SAM and SAH contents were also elevated in the HHcy group compared with other groups. Methylation of B1 repetitive elements was significantly increased in the HHcy group (0.5050 ± 0.0182) compared to the HLP (0.5158 ± 0.0163) and control (0.5589 ± 0.0236) groups. mRNA and protein expressions of LOX-1 increased (0.2877 ± 0.0341, 0.6090 ± 0.0547), whereas methylation expression decreased (0.5527 ± 0.0148) after 100 μM Hcy stimulation in ECs. In conclusion, Hcy-induced atherosclerosis was closely associated with induced hypomethylation status in the blood vessel, and this process was partially mediated by LOX-1 DNA methylation.