Department of Cardiology, Hunan Provincial People's Hospital, The First Hospital Affiliated With Hunan Normal University, Changsha, 410005, Hunan, People's Republic of China.
Departments of Cardiovascular Surgery, The Second Xiangya Hospital of Central South University, middle Ren-Min Road No. 139, Changsha, 410011, Hunan, People's Republic of China.
BMC Cardiovasc Disord. 2021 Sep 13;21(1):433. doi: 10.1186/s12872-021-02228-7.
A high level of total cholesterol is associated with several lipid metabolism disorders, including atherosclerosis and cardiovascular diseases. ATP-binding cassette (ABC) transporter A1 (ABCA1) and miR-33-5p play crucial roles in atherosclerosis by controlling cholesterol efflux. While citrate is a precursor metabolite for lipid and cholesterol synthesis, little is known about the association between citrate synthase (CS) and cholesterol efflux. This study investigated the role of the miR-33-5p/ABCA1/CS axis in regulating cholesterol efflux in vascular endothelial cells (VECs).
VECs were treated with oxidized low-density lipoprotein cholesterol (ox-LDL), or pretreated with plasmids overexpressing CS, ABCA1, siRNAs against CS and ABCA1, and an miR-33-5p inhibitor. Cell apoptosis, cellular senescence-associated β-galactosidase activity, inflammation, and cholesterol efflux were detected.
Treatment with ox-LDL decreased ABCA1 and CS levels and increased miR-33-5p expression and apoptosis in dose-dependent manners. In contrast, treatment with the miR-33-5p inhibitor and ABCA1 and CS overexpression plasmids inhibited the above-mentioned ox-LDL-induced changes. In addition, treatment with ox-LDL decreased cholesterol efflux, induced aging, and promoted the production of inflammatory cytokines (i.e., IL-6 and tumor necrosis factor TNF-α), as well as the expression of Bax and Caspase 3 proteins in VECs. All these changes were rescued by miR-33-5p inhibition and ABCA1 and CS overexpression. The inhibition of ABCA1 and CS by siRNAs eliminated the effects mediated by the miR-33-5p inhibitor, and knockdown of CS eliminated the effects of ABCA1 on VECs.
This study demonstrated the crucial roles played by the miR-33-5p/ABCA1/CS axis in regulating cholesterol efflux, inflammation, apoptosis, and aging in VECs, and also suggested the axis as a target for managing lipid metabolism disorders.
总胆固醇水平升高与多种脂质代谢紊乱有关，包括动脉粥样硬化和心血管疾病。三磷酸腺苷结合盒（ABC）转运体 A1（ABCA1）和 miR-33-5p 通过控制胆固醇外排在动脉粥样硬化中发挥关键作用。柠檬酸是脂质和胆固醇合成的前体代谢物，但柠檬酸合成酶（CS）与胆固醇外排之间的关系知之甚少。本研究探讨了 miR-33-5p/ABCA1/CS 轴在调节血管内皮细胞（VECs）胆固醇外排中的作用。
用氧化低密度脂蛋白胆固醇（ox-LDL）处理 VECs，或用 CS、ABCA1 过表达质粒预处理，用 CS 和 ABCA1 的 siRNAs 及 miR-33-5p 抑制剂预处理。检测细胞凋亡、衰老相关β-半乳糖苷酶活性、炎症和胆固醇外排。
ox-LDL 处理呈剂量依赖性降低 ABCA1 和 CS 水平并增加 miR-33-5p 表达和细胞凋亡。相反，用 miR-33-5p 抑制剂和 ABCA1 和 CS 过表达质粒处理可抑制上述 ox-LDL 诱导的变化。此外，ox-LDL 处理降低胆固醇外排，诱导衰老，并促进炎症细胞因子（即白细胞介素 6 和肿瘤坏死因子 TNF-α）的产生，以及 Bax 和 Caspase 3 蛋白在 VECs 中的表达。miR-33-5p 抑制和 ABCA1 和 CS 过表达均可挽救这些变化。siRNAs 抑制 ABCA1 和 CS 消除了 miR-33-5p 抑制剂介导的作用，CS 的敲低消除了 ABCA1 对 VECs 的作用。
本研究表明 miR-33-5p/ABCA1/CS 轴在调节 VECs 中的胆固醇外排、炎症、凋亡和衰老中发挥着重要作用，并提示该轴是管理脂质代谢紊乱的靶点。
