Department of Cardiovascular Ultrasound, The First Hospital of China Medical University, Shenyang, China.
Teaching Center for Basic Medical Experiment, China Medical University, Shenyang, China.
Vascul Pharmacol. 2021 Jun;138:106841. doi: 10.1016/j.vph.2021.106841. Epub 2021 Feb 2.
Coronary slow flow (CSF) refers to coronary arteries with no obvious stenosis but have slow coronary flow without effective treatment. The main cause of CSF is endothelial dysfunction. The long non-coding RNA (lncRNA) MALAT1 is involved in regulating endothelial dysfunction, but its role in CSF endothelial dysfunction is still unclear.
We included 41 CSF patients and 37 controls in the study, who all underwent coronary angiography, echocardiography, and brachial artery flow-mediated dilatation (FMD) examination. Human umbilical vein endothelial cells (HUVECs) stimulated by oxygen-glucose deprivation were used as CSF-induced HUVECs. Plasma endothelin-1 (ET-1) concentrations were determined by enzyme-linked immunosorbent assay (ELISA). The expression levels of MALAT1, miR-181b-5p, myocyte enhancer factor 2A (MEF2A), and ET-1 were measured by qRT-PCR or western blotting. Cell proliferation was determined by 5-ethynyl-2'-deoxyuridine (EdU) and Cell Counting Kit-8 (CCK-8) assays. Apoptosis was examined by flow cytometry. The relationship between miR-181b-5p and MALAT1 or MEF2A was verified by dual-luciferase reporter assay. MEF2A binding directly to the ET-1 promoter region was verified via chromatin immunoprecipitation (ChIP) assay.
MALAT1 and ET-1 were increased, and miR-181b-5p was decreased in the peripheral blood of the CSF patients, and could be used as predictors of CSF. In the CSF-induced HUVECs, MALAT1 was highly expressed, and MALAT1 knockdown improved endothelial function. In contrast, miR-181b-5p was downregulated in the CSF-induced HUVECs, and miR-181b-5p overexpression improved endothelial function. While MEF2A was highly enriched in CSF-induced HUVECs, MEF2A knockdown reduced ET-1 and increased the endothelial function of CSF-induced HUVECs as a transcriptional regulator of ET-1. MALAT1 modulated MEF2A expression positively by sponging miR-181b-5p.
Endothelial function is reduced in CSF. MALAT1 participates in regulating CSF endothelial dysfunction through the miR-181b-5p-MEF2A-ET-1 axis, and could provide a new target for CSF treatment.
冠状动脉慢血流（CSF）是指冠状动脉无明显狭窄但存在冠状动脉血流缓慢而无有效治疗的一种疾病。CSF 的主要发病机制为血管内皮功能障碍，长链非编码 RNA（lncRNA）MALAT1 参与调节血管内皮功能障碍，但在 CSF 血管内皮功能障碍中的作用尚不清楚。
纳入 41 例 CSF 患者和 37 例对照者，均行冠状动脉造影、超声心动图和肱动脉血流介导的舒张功能（FMD）检查。采用氧葡萄糖剥夺刺激人脐静脉内皮细胞（HUVECs）作为 CSF 诱导的 HUVECs。采用酶联免疫吸附试验（ELISA）检测血浆内皮素-1（ET-1）浓度。采用 qRT-PCR 或 Western blot 法检测 MALAT1、miR-181b-5p、肌细胞增强因子 2A（MEF2A）和 ET-1 的表达水平。采用 5-乙炔基-2'-脱氧尿苷（EdU）和细胞计数试剂盒-8（CCK-8）检测细胞增殖。采用流式细胞术检测细胞凋亡。采用双荧光素酶报告基因检测验证 miR-181b-5p 与 MALAT1 或 MEF2A 的关系。采用染色质免疫沉淀（ChIP）试验验证 MEF2A 是否直接结合 ET-1 启动子区域。
CSF 患者外周血中 MALAT1 和 ET-1 升高，miR-181b-5p 降低，可作为 CSF 的预测因子。CSF 诱导的 HUVECs 中 MALAT1 高表达，敲低 MALAT1 可改善血管内皮功能。相反，CSF 诱导的 HUVECs 中 miR-181b-5p 下调，过表达 miR-181b-5p 可改善血管内皮功能。CSF 诱导的 HUVECs 中 MEF2A 高度富集，敲低 MEF2A 可降低 ET-1 并增加 CSF 诱导的 HUVECs 的内皮功能，作为 ET-1 的转录调节因子。MALAT1 通过海绵 miR-181b-5p 正向调节 MEF2A 表达。
CSF 患者血管内皮功能降低。MALAT1 通过 miR-181b-5p-MEF2A-ET-1 轴参与调节 CSF 血管内皮功能障碍，可为 CSF 治疗提供新靶点。
