Key Laboratory of Cardiovascular Epidemiology & Department of Epidemiology, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, 167 Beilishi Road, Beijing 100037, China.
Key Laboratory of Cardiovascular Epidemiology & Department of Epidemiology, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, 167 Beilishi Road, Beijing 100037, China.
Atherosclerosis. 2019 Jun;285:31-39. doi: 10.1016/j.atherosclerosis.2019.04.204. Epub 2019 Apr 8.
Long non-coding RNAs (lncRNAs) have proven to be involved in the progression of atherosclerosis and dyslipidemia. In addition, vascular smooth muscle cells (VSMCs) phenotype switching, including VSMCs-derived foam cells formation, plays a key role in the pathogenesis of atherosclerosis. LncRNA ENST00000602558.1, one of the differentially expressed lncRNAs between coronary artery disease (CAD) patients and healthy controls identified by our previous study, was located to TG and HDL susceptibility loci, but its role and underlying mechanism in the pathogenesis of atherosclerosis remain unclear. The present study aims to explore the role and underlying mechanism of ENST00000602558.1 in the regulation of cholesterol efflux from VSMCs.
ABCG1 mRNA and protein expression in VSMCs was detected using qRT-PCR and Western blot, respectively. ABCG1-mediated cholesterol efflux to HDL from VSMCs was measured by means of NBD-cholesterol fluorescence intensity. The binding of ENST00000602558.1 to p65 and p65 to ABCG1 promoter region was detected by RNA immunoprecipitation (RIP) assay and chromatin immunoprecipitation (ChIP) assay, respectively.
Overexpression of ENST00000602558.1 downregulated ABCG1 mRNA and protein expression, while knockdown of ENST00000602558.1 upregulated ABCG1 mRNA and protein expression. Consistently, ENST00000602558.1 overexpression decreased ABCG1-mediated cholesterol efflux to HDL from VSMCs by 30.38% (p < 0.001), and knockdown of ENST00000602558.1 increased ABCG1-mediated cholesterol efflux to HDL from VSMCs by 30.41% (p = 0.001). In addition to cholesterol efflux, overexpression of ENST00000602558.1 increased lipid accumulation and TC/TG levels, while knockdown of ENST00000602558.1 decreased lipid accumulation and TC/TG levels in VSMCs. Furthermore, we confirmed that ENST00000602558.1 regulated ABCG1 expression and ABCG1-mediated cholesterol efflux from VSMCs through binding to p65.
In conclusion, ENST00000602558.1 played an important role in mediating cholesterol efflux to HDL from VSMCs by regulating ABCG1 expression through binding to p65.
长链非编码 RNA（lncRNA）已被证明参与动脉粥样硬化和血脂异常的进展。此外，血管平滑肌细胞（VSMCs）表型转换，包括 VSMCs 衍生的泡沫细胞形成，在动脉粥样硬化的发病机制中起着关键作用。lncRNA ENST00000602558.1 是我们之前的研究中鉴定出的冠心病（CAD）患者与健康对照之间差异表达的 lncRNA 之一，它位于 TG 和 HDL 易感基因座，但它在动脉粥样硬化发病机制中的作用和潜在机制尚不清楚。本研究旨在探讨 ENST00000602558.1 在调节 VSMCs 胆固醇外排中的作用及其潜在机制。
通过 qRT-PCR 和 Western blot 分别检测 VSMCs 中 ABCG1 mRNA 和蛋白的表达。通过 NBD-胆固醇荧光强度测量 ABCG1 介导的胆固醇从 VSMCs 向 HDL 的外排。通过 RNA 免疫沉淀（RIP）试验和染色质免疫沉淀（ChIP）试验分别检测 ENST00000602558.1 与 p65 以及 p65 与 ABCG1 启动子区域的结合。
ENST00000602558.1 的过表达下调了 ABCG1 mRNA 和蛋白的表达，而 ENST00000602558.1 的敲低则上调了 ABCG1 mRNA 和蛋白的表达。一致地，ENST00000602558.1 的过表达使 ABCG1 介导的胆固醇从 VSMCs 向 HDL 的外排减少了 30.38%（p<0.001），而 ENST00000602558.1 的敲低则使 ABCG1 介导的胆固醇从 VSMCs 向 HDL 的外排增加了 30.41%（p=0.001）。除了胆固醇外排外，ENST00000602558.1 的过表达增加了 VSMCs 中的脂质积累和 TC/TG 水平，而 ENST00000602558.1 的敲低则降低了 VSMCs 中的脂质积累和 TC/TG 水平。此外，我们通过证实 ENST00000602558.1 通过与 p65 结合调节 ABCG1 表达和 ABCG1 介导的胆固醇从 VSMCs 中的外排，从而证实了 ENST00000602558.1 在调节 ABCG1 表达和 ABCG1 介导的胆固醇从 VSMCs 中的外排方面发挥了重要作用。
总之，ENST00000602558.1 通过与 p65 结合调节 ABCG1 表达，从而在调节胆固醇从 VSMCs 向 HDL 的外排中发挥重要作用。
