Department of Pharmacology, Nantong University Pharmacy College, Nantong, China.
Department of Pharmacology, Nantong University Pharmacy College, Nantong, China.
Atherosclerosis. 2020 Jul;305:1-9. doi: 10.1016/j.atherosclerosis.2020.05.020. Epub 2020 Jun 16.
Murine double minute-2 (MDM2) has been poorly studied in cardiovascular diseases. The aim of the present study was to determine the biological role of MDM2 in inflammation activation and mitochondrial damage in human aortic endothelial cells (HAECs) stimulated with oxidized low-density lipoprotein (ox-LDL).
The expression of MDM2 in the aortas of atherosclerotic mice was determined. An adenoviral vector for MDM2 overexpression and siRNA for MDM2 downregulation were constructed and used to transfect HAECs. The functional changes in HAECs stimulated by ox-LDL were observed.
The protein expression of MDM2 was increased in atherosclerotic mice and ox-LDL-treated HAECs. In addition, ox-LDL-induced mRNA expression and secretion of TNF-α, IL-6 and IL-1β were significantly decreased by MDM2 downregulation and increased by MDM2 overexpression, and activation of NF-κB and caspase-1 was involved in the activity of MDM2. The ox-LDL-induced mitochondrial damage, indicated as increase in mitochondrial ROS production, decrease in mitochondrial membrane potential and elevation of mitochondrial DNA release, was significantly reversed by MDM2 downregulation and worsened by MDM2 overexpression. The ox-LDL-induced activation of TLR9/NF-κB and NLRP3/caspase-1 pathway was inhibited by MDM2 downregulation and worsened by MDM2 overexpression. The aggravation caused by MDM2 overexpression was abolished by mito-TEMPO. Treatment with mito-TEMPO significantly reduced the increase in mRNA expression and secretion of TNF-α, IL-6 and IL-1β induced by MDM2 overexpression in ox-LDL treated HAECs.
These findings suggest that MDM2 contributes to ox-LDL-induced inflammation via regulating mitochondrial damage.
鼠双微体 2（MDM2）在心血管疾病中的研究甚少。本研究旨在探讨 MDM2 在氧化型低密度脂蛋白（ox-LDL）刺激下人主动脉内皮细胞（HAECs）炎症激活和线粒体损伤中的作用。
检测动脉粥样硬化小鼠主动脉中 MDM2 的表达。构建 MDM2 过表达腺病毒载体和 MDM2 下调 siRNA，转染 HAECs。观察 ox-LDL 刺激下 HAECs 的功能变化。
在动脉粥样硬化小鼠和 ox-LDL 处理的 HAECs 中，MDM2 蛋白表达增加。此外，下调 MDM2 表达可显著降低 ox-LDL 诱导的 TNF-α、IL-6 和 IL-1β 的 mRNA 表达和分泌，而上调 MDM2 表达则增加其表达和分泌，NF-κB 和 caspase-1 的激活参与了 MDM2 的活性。ox-LDL 诱导的线粒体损伤，表现为线粒体 ROS 产生增加、线粒体膜电位降低和线粒体 DNA 释放增加，下调 MDM2 表达可显著逆转，而上调 MDM2 表达则加重。下调 MDM2 表达可抑制 ox-LDL 诱导的 TLR9/NF-κB 和 NLRP3/caspase-1 通路激活，而上调 MDM2 表达则加重其激活。MDM2 过表达引起的加重作用被 mito-TEMPO 消除。mito-TEMPO 处理可显著降低 ox-LDL 处理的 HAECs 中 MDM2 过表达引起的 TNF-α、IL-6 和 IL-1β mRNA 表达和分泌的增加。
这些发现表明，MDM2 通过调节线粒体损伤促进 ox-LDL 诱导的炎症。
