BACKGROUND In recent times, the medical science has developed by leaps and bounds, however, the molecular mechanism of pediatric pneumonia is still unclear. Although prior researches have shown that methyltransferase-like 3 (METTL3) is up-regulated in a variety of inflammatory diseases, its role and mechanism has been rarely studied in pediatric pneumonia, and need to be defined elaborately. OBJECTIVE In this study, the related molecular mechanism of METTL3 on inflammation and cell apoptosis in a pediatric pneumonia was investigated. MATERIALS AND METHODS Quantitative real-time polymerase chain reaction (qPCR) and western blot assays were employed to examine the mRNA and protein expression level of METTL3 and EZH2 in peripheral blood monocytes from pediatric pneumonia patients or cell model (WI-38). Then, qPCR and ELISA assay were applied to verify the inflammatory response in LPS-treated WI-38 cell lines after knockdown of METTL3. Besides, MTT cell viability assays, flow cytometry, and western blot assays were applied to examine the cell viability and cell apoptosis of LPS-treated WI-38 cell after knockdown of METTL3. Further, the western blot assays were employed to examine the protein expression levels of p-JAK2, JAK2, p-STAT3, STAT3, and EZH2 in LPS-treated WI-38 cell after knockdown of METTL3. Finally, ELISA and western blot were applied to verify the inflammatory response and cell apoptosis of LPS-treated WI-38 cell after knockdown of METTL3 and overexpression of EZH2. RESULTS In this study, the results showed that METTL3 and EZH2 were highly expressed in pediatric pneumonia patients and cell models (WI-38), respectively. Besides, downregulation of METTL3 inhibited LPS-induced inflammatory response and cell apoptosis. Then, the fact that METTL3 regulates the JAK2/STAT3 signaling pathway through EZH was proved. Furthermore, downregulation of METTL3 inhibits inflammation and apoptosis through EZH2. CONCLUSION This study found that METTL3 promotes inflammation and cell apoptosis in a pediatric pneumonia model by regulating EZH2.

中文翻译：

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METTL3 通过调节 EZH2 促进小儿肺炎模型中的炎症和细胞凋亡。

背景技术近年来，医学科学突飞猛进，但小儿肺炎的分子机制仍不清楚。虽然已有研究表明甲基转移酶样3（METTL3）在多种炎症性疾病中上调，但其在小儿肺炎中的作用和机制鲜有研究，需要详细界定。目的探讨METTL3在小儿肺炎炎症和细胞凋亡中的相关分子机制。材料和方法 采用定量实时聚合酶链反应 (qPCR) 和蛋白质印迹法检测小儿肺炎患者或细胞模型 (WI-38) 外周血单核细胞中 METTL3 和 EZH2 的 mRNA 和蛋白表达水平。然后，在敲低 METTL3 后，应用 qPCR 和 ELISA 测定来验证 LPS 处理的 WI-38 细胞系中的炎症反应。此外，应用 MTT 细胞活力测定、流式细胞术和蛋白质印迹测定来检查 LPS 处理的 WI-38 细胞在敲低 METTL3 后的细胞活力和细胞凋亡。此外，采用蛋白质印迹法检测敲低 METTL3 后 LPS 处理的 WI-38 细胞中 p-JAK2、JAK2、p-STAT3、STAT3 和 EZH2 的蛋白质表达水平。最后，应用ELISA和蛋白质印迹来验证LPS处理的WI-38细胞在敲低METTL3和过表达EZH2后的炎症反应和细胞凋亡。结果本研究结果显示METTL3和EZH2分别在小儿肺炎患者和细胞模型（WI-38）中高表达。除了，METTL3的下调抑制了LPS诱导的炎症反应和细胞凋亡。然后，证明了METTL3通过EZH调节JAK2/STAT3信号通路的事实。此外，METTL3 的下调通过 EZH2 抑制炎症和细胞凋亡。结论 本研究发现 METTL3 通过调节 EZH2 促进小儿肺炎模型中的炎症和细胞凋亡。