Differential response to lipopolysaccharide by JEG-3 and BeWo human choriocarcinoma cell lines

ObjectiveTo determine the effect of lipopolysaccharide (LPS) on NF-κB gene expression and proinflammatory cytokine release from trophoblast cell models, JEG-3 and BeWo human choriocarcinoma cells.Study designSerum-starved JEG-3 and BeWo cells were treated with LPS (from Escherichia coli serotype 0111:B4) for 24 or 48 h. Cell culture medium was collected and assayed for interleukin (IL)-1β, IL-6, IL-8, and transforming necrosis factor (TNF)-α cytokine release using enzyme-linked immunosorbent assays. RNA was extracted from the cells and real-time PCR was performed to measure NF-κB mRNA expression. All results were analyzed by one-way analysis of variance tests followed by Sidak's post hoc analysis. p < 0.05 was considered statistically significant.ResultsLPS triggered an inflammatory response in JEG-3 cells by inducing a 1.5-fold increase in NF-κB mRNA expression and TNF-α release (0 μg/mL: 15.13 ± 2.14, 1 μg/mL: 14.94 ± 0.75, 10 μg/mL: 23.05 ± 4.50, p < 0.05) and a 2-fold elevation in IL-6 secretion (0 μg/mL: 12.54 ± 5.44, 1 μg/mL: 25.54 ± 0.91, 10 μg/mL: 24.28 ± 4.43, p < 0.05). In contrast, BeWo cells were not as sensitive to LPS exposure; NF-κB mRNA expression was unchanged between LPS-treated and control cells, whereas a small but significant 1.3-fold increase in TNF-α release was found (TNF-α: 15.45 ± 1.53 pg/mL, control: 12.24 ± 1.00 pg/mL, p < 0.05). The inflammatory pathways in BeWo cells were found to be active given that treatment of these cells with IL-1β and TNF-α induced IL-6 secretion. Interestingly, 1 μg/mL LPS appeared to decrease IL-6 and TNF-α release from BeWo cells. IL-1β and IL-8 secretion were not detected from either cell lines.ConclusionLPS activates the NF-κB pathway in JEG-3 but not BeWo human choriocarcinoma cells and this may be the reason for their differential inflammatory response to LPS exposure.