BACKGROUND The 5-hydroxymethylcytosine (5hmC) DNA modification is an epigenetic marker involved in a range of biological processes. Its function has been studied extensively in tumors, neurodegenerative diseases, and atherosclerosis. Studies have reported that 5hmC modification is closely related to the phenotype transformation of vascular smooth muscle cells and endothelial dysfunction. However, its role in coronary artery disease (CAD) has not been fully studied. RESULTS To investigate whether 5hmC modification correlates with CAD pathogenesis and whether 5hmC can be used as a biomarker, we used a low-input whole-genome sequencing technology based on selective chemical capture (hmC-Seal) to firstly generate the 5hmC profiles in the circulating cell-free DNA(cfDNA) of CAD patients, including stable coronary artery disease (sCAD) patients and acute myocardial infarction (AMI) patients. We detected a significant difference of 5hmC enrichment in gene bodies from CAD patients compared with normal coronary artery (NCA) individuals. Our results showed that CAD patients can be well separated from NCA individuals by 5hmC markers. The prediction performance of the model established by differentially regulated 5hmc modified genes were superior to common clinical indicators for the diagnosis of CAD (AUC = 0.93) and sCAD (AUC = 0.93). Specially, we found that 5hmC markers in cfDNA showed prediction potential for AMI (AUC = 0.95), which was superior to that of cardiac troponin I, muscle/brain creatine kinase, and myoglobin. CONCLUSIONS Our results suggest that 5hmC markers derived from cfDNA can serve as effective epigenetic biomarkers for minimally noninvasive diagnosis and prediction of CAD.

中文翻译：

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循环无细胞 DNA 中的 5-羟甲基胞嘧啶特征作为冠状动脉疾病的诊断和预测生物标志物。

背景 5-羟甲基胞嘧啶 (5hmC) DNA 修饰是涉及一系列生物过程的表观遗传标记。其功能已在肿瘤、神经退行性疾病和动脉粥样硬化中得到广泛研究。有研究报道5hmC修饰与血管平滑肌细胞表型转化和内皮功能障碍密切相关。然而，其在冠状动脉疾病 (CAD) 中的作用尚未得到充分研究。结果 为了研究 5hmC 修饰是否与 CAD 发病机制相关以及 5hmC 是否可以用作生物标志物，我们使用基于选择性化学捕获 (hmC-Seal) 的低输入全基因组测序技术首先生成循环中的 5hmC 谱。 CAD患者的游离DNA（cfDNA），包括稳定型冠状动脉疾病（sCAD）患者和急性心肌梗死（AMI）患者。与正常冠状动脉 (NCA) 个体相比，我们检测到 CAD 患者基因体中 5hmC 富集的显着差异。我们的结果表明 CAD 患者可以通过 5hmC 标记与 NCA 个体很好地分开。差异调节的5hmc修饰基因建立的模型的预测性能优于诊断CAD（AUC = 0.93）和sCAD（AUC = 0.93）的常见临床指标。特别是，我们发现 cfDNA 中的 5hmC 标志物显示出对 AMI 的预测潜力（AUC = 0.95），优于心肌肌钙蛋白 I、肌肉/脑肌酸激酶和肌红蛋白。