International Medical Center, Geriatric Department, National Clinical Research Center for Geriatric Diseases, Xiangya Hospital of Central South University, Changsha, China.
Department of Cardiology, Changsha Central Hospital, Changsha, China.
J Cell Mol Med. 2020 Aug;24(15):8836-8848. doi: 10.1111/jcmm.15521. Epub 2020 Jun 28.
This study aims to explore the possible mechanism of TUG1 regulating ApoM in AS. To this end, expression levels of TUG1 and ApoM were measured in high fat dieted C57BL/6J mice, normal dieted C57BL/6J mice, ob/ob mice and db/db mice. LV-TUG1 or sh-TUG1 was injected into C57BL/6J mice before isolating peritoneal macrophages to measure cholesterol efflux (CE) and expression levels of ABCA1, ABCG1 and SR-BI. Meanwhile, CE in RAW264.7 cells was also measured after cell transfection. Dual luciferase reporter assay and anti-AGO2 RIP were applied to verify the relationship among TUG1, FXR1 and miR-92a. Total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterin (LDL-C), high-density lipoprotein cholesterol (HDL-C) as well as expressions of inflammatory cytokines (TNF-α, IL-1β and IL-6) in plasma were measured. Knock-down or expressed TUG1, FXR1 or miR-92a in NCTC 1469 cells or in ApoE-/- AS mice to determine the alteration on ApoM and plaque size. TUG1 was highly expressed while ApoM was down-regulated in high fat dieted C57BL/6J mice, b/ob and db/db mice. Overexpression of TUG1 could reduce the expression of ApoM, ABCA1 and ABCG1 in addition to slowing down CE rate. Reversed expression pattern was found in cells with knock-down of TUG1. TUG1 can compete with FXR1 to bind miR-92a. FXR1 negatively target ApoM. Overexpression of TUG1 in ApoE-/- mice can increase plaque size and enhance macrophage contents accordingly. TUG1 can inhibit ApoM in both liver tissues and plasma to inhibit CE through regulating miR-92a/ FXR1 axis. TUG1 is a promising target for AS treatment.
本研究旨在探讨 TUG1 调节载脂蛋白 M（ApoM）在动脉粥样硬化（AS）中的可能机制。为此，我们测量了高脂肪饮食喂养的 C57BL/6J 小鼠、正常饮食喂养的 C57BL/6J 小鼠、ob/ob 小鼠和 db/db 小鼠中 TUG1 和 ApoM 的表达水平。在分离腹腔巨噬细胞之前，向 C57BL/6J 小鼠注射 LV-TUG1 或 sh-TUG1，以测量胆固醇流出（CE）和 ABCA1、ABCG1 和 SR-BI 的表达水平。同时，还测量了 RAW264.7 细胞转染后的 CE。应用双荧光素酶报告基因检测和抗 AGO2 RIP 验证了 TUG1、FXR1 和 miR-92a 之间的关系。测量了血浆中总胆固醇（TC）、甘油三酯（TG）、低密度脂蛋白胆固醇（LDL-C）、高密度脂蛋白胆固醇（HDL-C）以及炎症细胞因子（TNF-α、IL-1β 和 IL-6）的表达水平。在 NCTC 1469 细胞或 ApoE-/-AS 小鼠中敲低或表达 TUG1、FXR1 或 miR-92a，以确定 ApoM 和斑块大小的变化。在高脂肪饮食喂养的 C57BL/6J 小鼠、ob/ob 和 db/db 小鼠中，TUG1 表达升高，而 ApoM 表达下调。TUG1 的过表达除了减缓 CE 速率外，还可以降低 ApoM、ABCA1 和 ABCG1 的表达。在 TUG1 敲低的细胞中发现了相反的表达模式。TUG1 可以与 FXR1 竞争结合 miR-92a。FXR1 负向靶向 ApoM。在 ApoE-/- 小鼠中过表达 TUG1 可以增加斑块大小，并相应增加巨噬细胞含量。TUG1 可以通过调节 miR-92a/FXR1 轴在肝组织和血浆中抑制 ApoM 来抑制 CE。TUG1 是治疗 AS 的一个有前途的靶点。
