Fig 1: The expression levels of FPR2 were significantly increased in the placenta tissues of patients with PE. (A) The expression levels of FPR2 in placenta tissues from CT (n = 10) and patients with PE (n = 10) were detected using immunohistochemistry analysis. Scale bar, 50 μm. (B) The expression levels of FPR2 were determined using western blotting analysis (***P < 0.001: PE vs CON group). (C) The expression levels of FPR2 in response to treatment of HTR8/SVneo cells with different concentrations of LPS (0, 10, 50 and 100 ng/mL, 1 and 5 μg/mL) (***P < 0.001: LPS vs CON group). (D) The expression levels of FPR2 following different durations of treatment (0, 3, 6, 12 and 24 h) in the presence of 100 ng/ml LPS (**P < 0.01, ***P < 0.001: LPS vs CON group)
Fig 2: The effects of FPR2 on the activation of the NF-κB signaling pathway. (A) The expression levels of the IκB-α, NF-κB/p65 and p-NF-κB/p65 proteins in the placental tissues from CT and patients with PE (*P < 0.05: PE vs CON group). (B) The expression levels of IκB-α, NF-κB (p65) and p-NF-κB/p65 in HTR8/SVneo cells following their exposure to different experimental conditions. (***P < 0.001: LPS vs CON group; + P < 0.05, + + P < 0.01: LPS + siFPR2 or LPS + WRW4 vs LPS group)
Fig 3: Knockdown of FPR2 expression or inhibition of its activity rescues the proliferation, apoptosis, migration, invasion and tube formation abilities of HTR8/SVneo cells pretreated with LPS. (A) The proliferation curves were determined using the CCK8 assay. The plots represent the proliferative ability of HTR8/SVneo cells (***P < 0.001: LPS vs CON group; + + P < 0.01: LPS + siFPR2 or LPS + WRW4 vs LPS group). (B) Annexin V-FITC/PI staining and flow cytometry assays were used to determine the percentage of apoptotic cells following their treatment with LPS, LPS + siFPR2 and LPS + WRW4. Histogram analysis indicates the apoptotic rate of the cells in each group (***P < 0.001: LPS vs CON group; + P < 0.05: LPS + siFPR2 or LPS + WRW4 vs LPS group). (C) Representative microphotographs of the wound healing assay of HTR8/SVneo cells under different conditions at the 0 and 24 h time points. The histogram indicates the migration area (μm2) in each group. Scale bar, 200 μm (***P < 0.001: LPS vs CON group; + + P < 0.01, + P < 0.05: LPS + siFPR2 or LPS + WRW4 vs LPS group). (D) The representative images of the Transwell invasion assay at 24 h in the different treatment groups. The histogram indicates the comparison of the cell counts in each group. Scale bar, 50 μm (**P < 0.01: LPS vs CON group; + P < 0.05: LPS + siFPR2 or LPS + WRW4 vs LPS group). (E) Representative images indicating the cell tube formation under different conditions at 4 h. Histogram indicating the quantification of the tube formation activity of HTR8/SVneo cells. Scale bar, 200 μm. (A-E) The LPS concentration used was 100 ng/ml. The siFPR2 and WRW4 concentrations used were 600 ng/ml and 10 μg/ml, respectively (**P < 0.01: LPS vs CON group; + P < 0.05: LPS + siFPR2 or LPS + WRW4 vs LPS group)
Fig 4: Knockdown of FPR2 expression and inhibition of its activity affects the release of inflammatory cytokines in HTR8/SVneo cells. (A) Determination of FPR2 protein levels in HTR8/SVneo cells transfected with siFPR2 (***P < 0.001: siFPR2 vs siNC group). (B) Estimation of the levels of proinflammatory cytokines (TNF-α, IL-1β, IL-6) and of the anti-inflammatory cytokine IL-10 in HTR8/SVneo cells. The LPS concentration used was 100 ng/ml, whereas the siFPR2 concentration used was 600 ng/ml and the WRW4 concentration was 10 μg/ml (**P < 0.01: LPS vs CON group; + P < 0.05, + + P < 0.01: LPS + siFPR2 or LPS + WRW4 vs LPS group)
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