The role of polyomavirus enhancer activator 3 in hyperoxic-induced alveolar epithelial cells type Ⅱ injury / 中华实用儿科临床杂志

ABSTRACT

Objective:To investigate the role of polyomavirus enhancer activator 3 (PEA3) in hyperoxia-induced injury of type Ⅱ alveolar epithelial cells (AEC Ⅱ) and the underlying mechanism.Methods:AEC Ⅱ cells were cultured in vitro and divided into hyperoxia group and normoxia group.After 24 h, 48 h and 72 h of hyperoxia or air treatment, cells were collected and the best treatment time was selected at 48 h. AEC Ⅱ cells were divided into 3 groups control group, negative control group (transfected with negative control) and PEA3 over expression group (transfected with PEA3 overexpression plasmid). Each group was further divided into hyperoxia subgroup and normoxia subgroup.Cells were harvested at 48 h after hyperoxia or normoxia treatment.Reactive oxygen species (ROS), Nod-like receptor domain 3 (NLRP3), monocyte chemoattractant protein-1 (MCP-1), interleukin(IL)-1β, IL-6, IL-8, IL-18, surfactant protein C (SP-C), aquaporins 5 (AQP5), PEA3 and manganese superoxide dismutase (MnSOD) levels were detected.Differences were compared by the t-test and repeated measures analysis of variance using SPSS 20.0 statistical software. Results:The interaction of grouping and treatment duration had significant effects on ROS, IL-1β, IL-6, IL-8, IL-18, SP-C and AQP5 levels in AEC Ⅱ cells ( F=19.857, 20.132, 23.133, 18.673, 28.341, 27.333 and 34.217, respectively, all P<0.05). At 24 h, 48 h and 72 h, ROS level in hyperoxia group was 1.78, 1.94 and 2.26 times higher than that in normoxia group ( t=18.649, 17.486 and 19.385, respectively all P<0.05). NLRP3 and MCP-1 levels were significantly upregulated in hyperoxia group.IL-1β level was 1.33, 1.69, and 1.65 times higher in hypoxia group at 24 h, 48 h and 72 h than that of normoxia group; IL-6 level was 1.26, 1.56 and 2.12 timers higher; IL-8 level was 1.13, 1.47 and 2.34 times higher; and IL-18 level was 1.46, 1.72 and 1.95 times higher, respectively (all P<0.05). The protein expression of SP-C was downregulated, while that of AQP5 was significantly upregulated in hypoxia group.The RNA expression of SP-C was 22%, 63% and 72% lower in hypoxia group than that in normoxia group at 24 h, 48 h and 72 h ( t=3.982, 16.328 and 20.259, P<0.05, respectively), and that of AQP5 was 1.92, 5.23 and 7.36 times higher ( t=14.631, 18.945 and 19.521, respectively, all P<0.05). There were significant differences in ROS, IL-1β, IL-6, IL-8, IL-18, SP-C and AQP5 levels at 24 h, 48 h and 72 h in hyperoxia group ( F=22.343, 20.566, 23.701, 19.222, 32.146, 40.278 and 37.107, respectively, all P<0.05). After 48 h of PEA3 overexpression, compared with the hyperoxic negative control group, ROS level in hyperoxic AEC Ⅱ cells overexpressing PEA3 decreased by 34% ( t=14.635, P<0.05). NLRP3 and MCP-1 were downregulated in hyperoxic AEC Ⅱ cells after overexpression of PEA3.IL-1β, IL-6, IL-8 and IL-18 levels decreased by 29%, 22%, 27% and 18%, respectively ( t=15.895, 17.872, 18.749 and 15.274, all P=0.000). SP-C was upre-gulated and AQP5 was downregulated by overexpression of PEA3 in hyperoxic AEC Ⅱ cells.In addition, PEA3 and MnSOD levels were significantly enhanced. Conclusions:Overexpression of PEA3 can alleviate the increase of ROS level in AEC Ⅱ cells, block the activation of various inflammatory pathways and reduce the transformation from AEC Ⅱ to AEC Ⅰ cells via enhancing MnSOD level.