MicroRNA-155 Promotes Heat Stress-Induced Inflammation via Targeting Liver X Receptor α in Microglia
MicroRNA-155 Promotes Heat Stress-Induced Inflammation via Targeting Liver X Receptor α in Microglia
复制标题
MicroRNA-155 通过靶向小胶质细胞中的肝脏 X 受体 α 促进热应激诱发的炎症
DOI：
10.3389/fncel.2019.00012
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发表时间：
2019-02-04
影响因子：
5.3
通讯作者：
Yang, Xue-Sen
中科院分区：
文献类型：
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作者：
Li, Ping;Wang, Gong;Yang, Xue-Sen
背景：小胶质细胞的神经炎症反应在中暑引起的脑功能障碍过程中发挥着重要作用。据报道，MicroRNA 参与复杂的信号网络，并已被确定为神经炎症调节剂。在这项研究中，我们确定了 microRNA-155 在热应激小胶质细胞炎症反应中的生物学作用，并探讨了其潜在机制。方法：使用MicroRNA-155模拟物和抑制剂分别上调或下调microRNA-155的表达。使用小胶质细胞标记物 CD11b 和 CD68 通过免疫反应评估 BV-2 小胶质细胞（BV-2 细胞）的激活状态。使用实时逆转录聚合酶链反应（RT-PCR）和酶联免疫吸附测定（ELISA）测量诱导白细胞介素-1β（IL-1β）、白细胞介素-6（IL-6）和肿瘤坏死因子-α（TNF-α）的水平。通过抑制性 kappa B α (IκBα) 和 NF-κB p65 磷酸化的蛋白质印迹法以及使用 p65 磷酸化抗体的间接免疫荧光分析来评估核因子 kappa B (NF-κB) 信号蛋白的激活。使用荧光素酶报告基因测定来验证肝脏 X 受体 α (LXRα) 作为 microRNA-155 的靶基因。结果：热应激显着诱导IL-1β、IL-6和TNF-α释放，并增加CD11b和CD68的表达。此外，热应激使 IκBα 和 NF-κB p65 磷酸化显着增加，并且 microRNA-155 表达也升高。热应激小胶质细胞中 microRNA-155 的高表达与 LXRα 表达呈负相关。然后我们确定了 microRNA-155 在热应激诱导的炎症反应中的作用。结果显示，通过靶向 LXRα，microRNA-155 增强了 NF-κB 信号传导激活，并促进热应激处理的 BV-2 细胞中的免疫炎症。结论：MicroRNA-155 促进小胶质细胞热应激诱导的炎症反应。潜在机制可能包括通过靶向 LXRα 增加 NF-κB 通路激活来促进炎症因子表达。
Background: The neuroinflammatory responses of microglial cells play an important role in the process of brain dysfunction caused by heat stroke. MicroRNAs are reportedly involved in a complex signaling network and have been identified as neuroinflammatory regulators. In this study, we determined the biological roles of microRNA-155 in the inflammatory responses in heat-stressed microglia and explored the underlying mechanisms. Methods: MicroRNA-155 mimic and inhibitor were used to separately upregulate or downregulate microRNA-155 expression. The activation state of BV-2 microglial cells (BV-2 cells) was assessed via immunoreactions using the microglial marker CD11b and CD68. Levels of induced interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were measured using real-time reverse transcription polymerase chain reaction (RT-PCR) and enzyme linked immunosorbent assays (ELISAs). The activation of nuclear factor kappa B (NF-κB) signaling proteins was evaluated by Western blotting for inhibitory kappa B alpha (IκBα) and NF-κB p65 phosphorylation and indirect immunofluorescence analysis using a p65 phosphorylation antibody. A luciferase reporter assay was used to verify liver X receptor α (LXRα) as a target gene of microRNA-155. Results: Heat stress significantly induced IL-1β, IL-6, and TNF-α release and increased the expression of CD11b and CD68. In addition, IκBα and NF-κB p65 phosphorylation were dramatically increased by heat stress, and microRNA-155 expression was also elevated. High expression of microRNA-155 in heat-stressed microglial cells was inversely correlated with LXRα expression. We then determined the role of microRNA-155 in the heat stress-induced inflammatory responses. The results revealed that by targeting LXRα, microRNA-155 enhanced NF-κB signaling activation and facilitated immune inflammation in heat stress-treated BV-2 cells. Conclusion: MicroRNA-155 promotes heat stress-induced inflammatory responses in microglia. The underlying mechanisms may include facilitating inflammatory factors expression by increasing NF-κB pathway activation via targeting LXRα.