Department of Pharmacy, Puxing Community Health Service Center, 250 Gui Chang Road, Pudong New District, Shanghai 200129, People's Republic of China.
J Biosci. 2020;45.
Herein, we found that serum concentration of superoxide dismutase 3 (SOD3) was significantly reduced in children with mycoplasma pneumonia (MP) infection. To study the roles of SOD3 in inflammatory regulation of MP infection, human A549 type II alveolar epithelial cells were stimulated with 10 CCU/ml of MP to build MP infection . Secretion of pro-inflammatory cytokine interleukin (IL)-8 and tumor necrosis factor (TNF)-α were measured via enzyme-linked immunosorbent assay (ELISA) to assess the inflammatory response of A549 cells. Levofloxacin (LVFX) was used as an anti-inflammatory drug while recombinant TNF-α was used as an inflammatory promotor in MP-infected cells. Transcriptional activity of nuclear factor (NF)-κB was assessed by detecting protein levels of nuclear NF-κB and cytoplasm NF-κB using Western blot analysis. Our data suggested that the expression of SOD3 mRNA and protein, as well as content of SOD3 in cultured supernatant, were time-dependently inhibited in MP-infected A549 cells. However, lentiviruses-mediated SOD3 overexpression alleviated inflammatory response of MP-infected A549 cells, and prevented the unclear translocation of NF-κB, as evidenced by obviously reducing the production of IL-8 and TNF-α in cell cultured supernatant, as well as decreasing nuclear NF-κB while increasing cytoplasm NF-κB. Inspiringly, SOD3 overexpression induced anti-inflammatory effect and the inactivation of NF-κB was similar to that of 2 lg/ml of LVFX, but reversed by additional TNF-α treatment. Therefore, we can conclude that transcriptional activity of NF-jB was the underlying mechanism, by which SOD3 regulated inflammatory response in MP infection
在此，我们发现肺炎支原体（MP）感染患儿血清超氧化物歧化酶 3（SOD3）浓度显著降低。为研究 SOD3 在 MP 感染炎症调控中的作用，用 10 CCU/ml 的 MP 刺激人 A549 型 II 型肺泡上皮细胞，建立 MP 感染模型。通过酶联免疫吸附试验（ELISA）检测促炎细胞因子白细胞介素（IL）-8 和肿瘤坏死因子（TNF）-α的分泌，评估 A549 细胞的炎症反应。左氧氟沙星（LVFX）作为抗炎药物，重组 TNF-α作为 MP 感染细胞的炎症促进剂。通过 Western blot 分析检测核因子（NF）-κB 的蛋白水平，评估核 NF-κB 和细胞质 NF-κB 的转录活性。我们的数据表明，在 MP 感染的 A549 细胞中，SOD3 mRNA 和蛋白的表达以及培养上清液中 SOD3 的含量呈时间依赖性抑制。然而，慢病毒介导的 SOD3 过表达减轻了 MP 感染的 A549 细胞的炎症反应，并阻止了 NF-κB 的不清楚易位，这表现在细胞培养上清液中 IL-8 和 TNF-α的产生明显减少，细胞质 NF-κB 增加，核 NF-κB 减少。令人鼓舞的是，SOD3 过表达诱导抗炎作用和 NF-κB 的失活与 2 lg/ml 的 LVFX 相似，但在额外添加 TNF-α处理后被逆转。因此，我们可以得出结论，NF-jB 的转录活性是 SOD3 调节 MP 感染中炎症反应的潜在机制。
