Lv Bo, Cheng Xiyuan, Sharp Frank R, Ander Bradley P, Liu Da Zhi
Department of Neurology, University of California, Davis, Davis, CA, United States.
Department of Critical Care Medicine and Emergency, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.
Front Neurosci. 2018 Oct 24;12:767. doi: 10.3389/fnins.2018.00767. eCollection 2018.
Our previous study demonstrated miR-122 mimic decreased NOS2 expression in blood leucocytes and improved stroke outcomes when given immediately after middle cerebral artery occlusion (MCAO) in rats. Since NOS2 is associated with neuro-inflammation in stroke and decreasing NOS2 expression alone in leucocytes is insufficient to improve stroke outcomes, we hypothesized that miR-122 mimic may also decrease NOS2 expression in brain microvascular endothelial cells (BMVECs) even at extended time windows. We administered PEG-liposome wrapped miR-122 mimic (2.4 mg/kg, i.v.) 0 or 6 h after MCAO, and assessed stroke volume and NOS2 expression in BMVECs 24 h following MCAO in rats. Luciferase reporter assays were used to determine if miR-122 binds to 3' untranslated regions (3'UTR) of NOS2. The data showed that miR-122 mimic decreased infarct volumes and decreased MCAO-induced NOS2 over-expression in BMVECs. However, miR-122 did not bind to 3'UTR of NOS2 in the luciferase assays. The data show the 6-h period of therapeutic efficacy of miR-122 mimic which could relate to indirect knockdown of NOS2 in both BMVECs and leucocytes.
我们之前的研究表明，在大鼠大脑中动脉闭塞（MCAO）后立即给予miR-122模拟物，可降低血液白细胞中一氧化氮合酶2（NOS2）的表达，并改善中风结局。由于NOS2与中风中的神经炎症相关，且仅降低白细胞中NOS2的表达不足以改善中风结局，我们推测即使在延长的时间窗内，miR-122模拟物也可能降低脑微血管内皮细胞（BMVECs）中NOS2的表达。我们在MCAO后0或6小时静脉注射聚乙二醇脂质体包裹的miR-122模拟物（2.4mg/kg），并在大鼠MCAO后24小时评估BMVECs中的梗死体积和NOS2表达。使用荧光素酶报告基因测定来确定miR-122是否与NOS2的3'非翻译区（3'UTR）结合。数据显示，miR-122模拟物可减少梗死体积，并降低MCAO诱导的BMVECs中NOS2的过表达。然而，在荧光素酶测定中，miR-122未与NOS2的3'UTR结合。数据显示了miR-122模拟物6小时的治疗效果期，这可能与BMVECs和白细胞中NOS2的间接敲低有关。
