ObjectiveTo establish a cell inflammation model induced by tumor necrosis factor-α (TNF-α) in human bronchus epithelial cells, and investigate the effects of glutathione S-transferase mu 5 (GSTM5) on the inflammation and oxidative stress. Methods16HBE cells were treated with TNF-α (10 ng/mL, 24 h) in the absence or presence of the constructed GSTM5 eukaryotic expression vector (1 μg/mL). The concentration of malondialdehyde (MDA) and total antioxidation capacity (T-AOC) were detected by colorimetric method. The survival rate of cells was assessed by the methyl thiazolyl tetrazolium (MTT) assay. The transcription level of NADPH oxidase-1 (NOX1), NOX2, NOX3, NOX4, NOX5, dual oxidase-1 (DUOX1) and DUOX2 were evaluated by RT-PCR. Western blot was performed to investigate the protein levels of NOX1 and NOX2. ResultsTNF-α simulation significantly increased the level of MDA in cells, and decreased the level of T-AOC and survival rate of 16HBE. When transfected with the GSTM5 eukaryotic expression vector, the concentration of MDA significantly decreased (P < 0.05), and the activation of T-AOC increased dramatically (P < 0.05). Consequently, the survival rate of 16HBE in the GSTM5 group improved (P < 0.05). The 16HBE cells transfected with the constructed GSTM5 eukaryotic expression vector had a lower transcription and protein levels of NOX1 and NOX2 (all P < 0.01). There were no significant changes in the mRNA expressions of NOX3, NOX4, NOX5, DUOX1 or DUOX2. ConclusionGSTM5 may down-regulate the transcription level of NOX1 and NOX2 to reduce the inflammation and oxidative stress induced by TNF-α.
ObjectiveTo establish 16HBE cell lines stably expressing glutathione S-transferase mu 5 (GSTM5) gene, and explore the mechanism of GSTM5 nuclear translocation. MethodsRecombinant lentiviral expression vector containing GSTM5 gene was constructed and lentivirus was produced. After lentivirus infection of 16HBE cells, 16HBE-GSTM5 cell lines were obtained by screening with puromycin. Expression of GSTM5 in different cells was examined by RT-qPCR and Western blot. The nuclear translocation of GSTM5 was observed by confocal laser scanning microscope, after the 16HBE-GSTM5 cell lines were treated with tumor necrosis factor-α (TNF-α; 10 ng/ml) for 0.5 hour. ResultsLentiviral expression plasmids, PLVX-puro-3*flag-SBP-GSTM5-C and PLVX-puro-GSTM5-SBP-3*flag-N, were constructed and lentiviral particles were successfully packed. After infected with lentivirus and screened by puromycin, two cell lines, 16HBE-GSTM5-SBP-3*flag-N and 16HBE-3*flag-SBP-GSTM5-C, were obtained. GSTM5 expression in these two cell lines was significantly higher compared with the control group and parental cells. After treated with TNF-α for 0.5 hour, the nuclear translocation of GSTM5 in 16HBE-GSTM5-SBP-3*flag-N was much more obviously than that in 16HBE-3*flag-SBP-GSTM5-C. ConclusionThe N-terminal region of GSTM5 is critical for nuclear translocation induced by TNF-α, which is mediated by a novel and non-classical nuclear localization signal.