Postdoctoral Workstation, General Hospital of Ningxia Medical University, Yinchuan, China.
Acta Biochim Biophys Sin (Shanghai). 2012 Oct;44(10):866-75. doi: 10.1093/abbs/gms075.
Atherosclerosis (AS) is a disease induced by multiple factors, including genetic and environmental elements. The aim of the present study is to investigate the comprehensive effects of high cholesterol, high methionine diet, and apolipoprotein E deficiency (ApoE(-/-)) on the pathogenesis of AS. ApoE(-/-) mice were fed with high cholesterol and methionine diet for 15 weeks to induce hyperlipidemia and hyperhomocysteinemia. The methylation levels of genomic DNA (gDNA) and B1 repetitive elements in aortic tissues were measured by both methylation-dependent restriction analysis and nested methylation-specific polymerase chain reaction (PCR). Methylation sequence-bias pattern was assayed by DNA methyl-accepting capacity with restriction endonuclease digestion. The mRNA expression of DNA methyltransferase-1, 3 (DNMT1, 3) was detected by real-time PCR. The concentrations of S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) were determined by high-performance liquid chromatography. The results showed hypomethylation of gDNA and B1 repetitive elements. The mRNA expression of DNMT1 was reduced. The levels of SAM, SAH, and SAM/SAH ratio were increased. The atherosclerotic lesion areas strongly correlated with the risk factors. The distribution of DNA demethylation was preferred to non-CpG islands, which may suggest the major impact of hypomethylation on DNA integrity and genomic instability. Overall, our data unequivocally showed that the comprehensive role of high cholesterol, high methionine diet, and ApoE(-/-) is not uniformly consistent with the role of a single risk factor. The DNA methylation pattern in AS is quite complex and depends on genetic background and many involved risk factors.
动脉粥样硬化（AS）是一种由多种因素引起的疾病，包括遗传和环境因素。本研究旨在探讨高胆固醇、高蛋氨酸饮食和载脂蛋白 E 缺乏（ApoE（-/-））对 AS 发病机制的综合影响。用高胆固醇和蛋氨酸饮食喂养 ApoE（-/-）小鼠 15 周，以诱导高脂血症和高同型半胱氨酸血症。通过甲基化依赖性限制性分析和巢式甲基化特异性聚合酶链反应（PCR）测量主动脉组织中基因组 DNA（gDNA）和 B1 重复元件的甲基化水平。通过用限制性内切酶消化测定 DNA 甲基化接受能力来测定甲基化序列偏倚模式。通过实时 PCR 检测 DNA 甲基转移酶-1、3（DNMT1、3）的 mRNA 表达。通过高效液相色谱法测定 S-腺苷甲硫氨酸（SAM）和 S-腺苷同型半胱氨酸（SAH）的浓度。结果显示 gDNA 和 B1 重复元件的低甲基化。DNMT1 的 mRNA 表达减少。SAM、SAH 和 SAM/SAH 比值升高。动脉粥样硬化病变面积与危险因素密切相关。去甲基化的分布优先于非 CpG 岛，这可能表明低甲基化对 DNA 完整性和基因组不稳定性的主要影响。总之，我们的数据明确表明，高胆固醇、高蛋氨酸饮食和 ApoE（-/-）的综合作用与单一危险因素的作用并不完全一致。AS 中的 DNA 甲基化模式相当复杂，取决于遗传背景和许多涉及的危险因素。
