Department of Pharmacology, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, College of Pharmacy, Harbin Medical University, Harbin, 150081, Heilongjiang, People's Republic of China.
Department of Pathology and Pathophysiology, College of Basic Medical Sciences, Harbin Medical University-Daqing, Daqing, 163319, Heilongjiang, People's Republic of China.
J Transl Med. 2023 Feb 8;21(1):97. doi: 10.1186/s12967-023-03962-6.
Atherosclerosis is driven by synergistic interactions between pathological biomechanical and lipid metabolic factors. Long noncoding RNAs (LncRNAs) have been implicated in atherogenesis. The purpose of this study was to investigate the potential mechanism of lncRNA AI662270 on macrophage cholesterol transport in atherosclerosis.
Apolipoprotein E deficiency (ApoE) mice were fed a high fat diet for 16 weeks to construct atherosclerotic model, and the mice were injected with recombinant lentivirus carrying AI662270 gene to overexpress AI662270. Macrophages were cleared by liposomal clondronate in vivo. Fundamental experiments and functional assays, hematoxylin and eosin staining, oil red O staining and others, were performed to evaluate the function of AI662270 on atherogenesis. Peritoneal macrophages were treated with oxidized low density lipoprotein (ox-LDL) to simulate in vitro model. Mechanism assays, RNA-interacting protein immunoprecipitation, RNA-protein pulldown and others, were performed to study the regulatory mechanism of AI662270 in macrophages.
The novel AI662270 was mainly enriched in macrophages, but not in endothelial cells, smooth muscle cells and fibroblasts of mouse atherosclerotic lesions and was upregulated by ox-LDL. Overexpression of AI662270 resulted in lipid accumulation, larger atherosclerotic plaques and cardiac dysfunction in vivo. After macrophages were removed, the pro-atherogenic effect of AI662270 disappeared. Downregulation of AI662270 in macrophages protected against foam cell formation by potentiating cholesterol efflux and reducing intracellular total cholesterol. The opposite effect was observed in macrophage-specific AI662270-overexpressed cells in vitro. AI662270 bound to adenosine triphosphate-binding cassette transporter A1 (Abca1) responsible for regulating cholesterol efflux in macrophages. Forced expression of AI662270 in macrophages decreased Abca1 expression. The reverse occurred when expression of AI662270 was repressed.
These findings reveal an essential role for AI662270 in atherosclerosis progression by regulating cholesterol efflux from macrophages.
动脉粥样硬化是由病理生物力学和脂质代谢因素的协同相互作用驱动的。长链非编码 RNA（lncRNA）与动脉粥样硬化的发生有关。本研究旨在探讨 lncRNA AI662270 对动脉粥样硬化中巨噬细胞胆固醇转运的潜在机制。
用高脂饮食喂养载脂蛋白 E 缺陷（ApoE）小鼠 16 周构建动脉粥样硬化模型，并用携带 AI662270 基因的重组慢病毒转染小鼠以过表达 AI662270。体内用脂质体氯膦酸盐清除巨噬细胞。进行苏木精和伊红染色、油红 O 染色等基础实验和功能测定，以评估 AI662270 对动脉粥样硬化形成的作用。用氧化型低密度脂蛋白（ox-LDL）处理腹腔巨噬细胞模拟体外模型。进行 RNA 相互作用蛋白免疫沉淀、RNA 蛋白下拉等机制测定，以研究 AI662270 在巨噬细胞中的调节机制。
新型 AI662270 主要富集在巨噬细胞中，而不是在小鼠动脉粥样硬化病变的内皮细胞、平滑肌细胞和成纤维细胞中，并且由 ox-LDL 上调。AI662270 的过表达导致体内脂质积累、更大的动脉粥样硬化斑块和心脏功能障碍。去除巨噬细胞后，AI662270 的促动脉粥样硬化作用消失。在体外，下调巨噬细胞中的 AI662270 可通过增强胆固醇流出和减少细胞内总胆固醇来保护泡沫细胞形成。在巨噬细胞特异性过表达 AI662270 的细胞中观察到相反的效果。AI662270 与负责调节巨噬细胞胆固醇流出的三磷酸腺苷结合盒转运体 A1（Abca1）结合。在巨噬细胞中强制表达 AI662270 会降低 Abca1 的表达。当 AI662270 的表达受到抑制时，情况则相反。
这些发现揭示了 AI662270 通过调节巨噬细胞胆固醇流出在动脉粥样硬化进展中的重要作用。
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