Background. Propofol is a widely used intravenous anesthetic drug with potential neuroprotective effect in diverse diseases of neuronal injuries such as traumatic brain injury and ischemic stroke. However, the underlying molecular mechanism remains largely unknown. Methods. Real-time qPCR, enzyme-linked immunosorbent assay, and Western blotting were used to identify the expression pattern of miR-221/222, inflammatory genes, cytokines, and IRF2. The biological roles and mechanisms of propofol in microglia activation were determined in BV2 cells and primary microglia. Bioinformatic analysis and luciferase reporter assay were used to confirm the regulatory role of miR-221/222 in Irf2 expression. Results. We found that miR-221 and miR-222 were downstream targets of propofol and were consistently upregulated in lipopolysaccharide- (LPS-) primed BV2 cells. Gain- and loss-of-function studies revealed that miR-221 and miR-222 were profoundly implicated in microglia activation. Then, interferon regulatory factor 2 (Irf2) was identified as a direct target gene of miR-221/222. IRF2 protein levels were reduced by miR-221/222 and increased by propofol treatment. Ectopic expression of IRF2 attenuated the proinflammatory roles induced by LPS in BV2 cells. More importantly, the suppressive effects of propofol on LPS-primed activation of BV2 cells or primary mouse microglia involved the inhibition of miR-221/222-IRF2 axis. Conclusions. Our study highlights the critical function of miR-221/222, which inhibited Irf2 translation, in the anti-inflammatory effects of propofol, and provides a new perspective for the molecular mechanism of propofol-mediated neuroprotective effect.

中文翻译：

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异丙酚通过靶向 MicroRNA-221/222-IRF2 轴改善小胶质细胞活化

背景。丙泊酚是一种广泛使用的静脉麻醉药，对多种神经元损伤疾病如创伤性脑损伤和缺血性中风具有潜在的神经保护作用。然而，潜在的分子机制仍然很大程度上未知。方法。实时 qPCR、酶联免疫吸附测定和蛋白质印迹用于鉴定 miR-221/222、炎症基因、细胞因子和 IRF2 的表达模式。在 BV2 细胞和原代小胶质细胞中确定了丙泊酚在小胶质细胞活化中的生物学作用和机制。生物信息学分析和荧光素酶报告基因分析用于确认 miR-221/222 在 Irf2 表达中的调节作用。结果. 我们发现 miR-221 和 miR-222 是丙泊酚的下游靶标，并且在脂多糖 (LPS-) 引发的 BV2 细胞中持续上调。功能增益和功能丧失研究表明，miR-221 和 miR-222 与小胶质细胞活化密切相关。然后，干扰素调节因子2（Irf2）被鉴定为miR-221/222的直接靶基因。miR-221/222 降低 IRF2 蛋白水平，丙泊酚处理提高 IRF2 蛋白水平。IRF2 的异位表达减弱了 LPS 在 BV2 细胞中诱导的促炎作用。更重要的是，丙泊酚对 LPS 引发的 BV2 细胞或原代小鼠小胶质细胞活化的抑制作用涉及 miR-221/222-IRF2 轴的抑制。结论。我们的研究强调了 miR-221/222 的关键功能，它抑制Irf2翻译，在丙泊酚的抗炎作用中，为丙泊酚介导的神经保护作用的分子机制提供了新的视角。