OBJECTIVE Inflammasome contributes to ischemic brain injury by inducing pyroptosis and inflammation. The aim of this study is to unravel the mechanism of long non-coding RNA (lncRNA) maternally expressed gene 3 (MEG3)-mediated regulation of absent in melanoma 2 (AIM2) inflammasome during cerebral ischemia/reperfusion (I/R). METHODS In vivo middle cerebral artery occlusion (MCAO) rat model and in vitro oxygen-glucose deprivation/reperfusion (OGD/R)-treated neurocytes model were generated. TTC, H&E staining and TUNEL were performed to assess the cerebral ischemic injury. LDH and MTT assays were used to detect cell viability and cytotoxicity. qRT-PCR was used to detect the expression levels of MEG3, miR-485 and AIM2. Immunohistochemistry (IHC) and immunofluorescence were conducted to detect the AIM2 expression. ELISA and Western blotting were performed to determine the secretion and protein levels of inflammasome signaling proteins. Dual luciferase reporter assay and Ago2-RIP were used to validate the direct interaction among MEG3, miR-485 and AIM2. RESULTS In both MCAO rats and OGD/R-treated neurocytes, MEG3 and AIM2 were significantly up-regulated, whereas miR-485 was down-regulated. MCAO induces pyroptosis and release of IL-1β and IL-18 in ischemia brain. MEG3 acted as a molecular sponge to suppress miR-485, and AIM2 was identified as a direct target of miR-485. Knockdown of MEG3 inhibited OGD/R-induced pyroptosis and inflammation, and lack of MEG3 inhibited caspase1 signaling and decreased the expression of AIM2, ASC, cleaved-caspase1 and GSDMD-N. While overexpression of MEG3 exerted opposite effects. CONCLUSION MEG3/miR-485/AIM2 axis contributes to pyroptosis via activating caspase1 signaling during cerebral I/R, suggesting that this axis may be a potent therapeutic target in ischemic stroke.

中文翻译：

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较长的非编码RNA MEG3通过靶向miR-485 / AIM2轴来增加细胞凋亡，从而促进脑缺血再灌注损伤。

目的炎性小体通过诱导细胞凋亡和炎症而导致缺血性脑损伤。这项研究的目的是揭示脑缺血/再灌注（I / R）期间长非编码RNA（lncRNA）母本表达基因3（MEG3）介导的黑色素瘤2（AIM2）炎性小体中缺失的调节机制。方法建立体内大脑中动脉闭塞（MCAO）大鼠模型和体外氧葡萄糖剥夺/再灌注（OGD / R）处理的神经细胞模型。进行TTC，H＆E染色和TUNEL评估脑缺血性损伤。LDH和MTT分析用于检测细胞活力和细胞毒性。使用qRT-PCR检测MEG3，miR-485和AIM2的表达水平。进行了免疫组织化学（IHC）和免疫荧光检测AIM2表达。进行ELISA和Western印迹法测定炎性小体信号蛋白的分泌和蛋白水平。使用双重荧光素酶报告基因测定法和Ago2-RIP来验证MEG3，miR-485和AIM2之间的直接相互作用。结果在MCAO大鼠和OGD / R处理的神经细胞中，MEG3和AIM2均显着上调，而miR-485则下调。MCAO诱导缺血性脑干细胞凋亡并释放IL-1β和IL-18。MEG3充当抑制miR-485的分子海绵，而AIM2被确定为miR-485的直接靶标。敲低MEG3抑制OGD / R诱导的凋亡和炎症，而缺少MEG3抑制caspase1信号传导并降低AIM2，ASC，裂解的caspase1和GSDMD-N的表达。虽然MEG3的过表达发挥相反的作用。