RESUMO
Objective:To investigate the expression level of transcription factor dimerization partner 2 (TFDP2) in the placentas of women with preeclampsia, and analyze its effect on the apoptosis of trophoblast cells.Methods:Placental tissues from thirty puerperae with preeclampsia who gave birth by cesarean section in Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School between January 2018 and December 2022 (preeclampsia group) and 30 healthy puerperae undergoing cesarean section during the same period (control group) were retrospectively selected. Immunohistochemistry was used to localize TFDP2 in the placental tissues. Real-time quantitative-polymerase chain reaction (qRT-PCR) and Western blot were used to detect the differences in expression of TFDP2 at mRNA and protein levels in placental tissues between the two groups. Forskolin-exposed BeWo cells were transfected with small interfering RNA (siRNA) to knockdown TFDP2 and the changes in the expression of apoptosis-related indicators, B cell lymphoma 2 (Bcl2) and Bcl2 associated X (Bax), at protein and mRNA levels were analyzed by Western blot and qRT-PCR, respectively. Besides, the change in the apoptosis level of BeWo cells was detected using terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) staining and flow cytometry. Downstream signaling pathways were analyzed to understand the involved molecular mechanisms. Two independent samples t-test, Wilcoxon rank-sum test, and Chi-square test were used for statistical analysis. Results:TFDP2 was mostly localized in the syncytiotrophoblasts and the extravillous trophoblasts in the normal placentas. TFDP2 expression in the syncytiotrophoblasts was lower in the preeclampsia group than in the control group at both mRNA (0.722±0.239 vs. 1.000±0.348, t=3.61, P=0.001) and protein (0.728±0.185 vs. 1.000±0.206, t=2.41, P=0.037) levels. Comparing the group without knockdown of TFDP2, the knockdown of TFDP2 in BeWo cells elevated the Bax/Bcl2 ratio (mRNA: 1.755±0.452 vs. 1.000±0.279, t=3.48, P=0.006; protein: 3.206±0.922 vs. 1.000±0.290, t=3.95, P=0.017), and increased cell apoptosis both in number and ratio (TUNEL staining: 4.556±1.740 vs. 2.444±1.130, t=3.05, P=0.008; flow cytometry: 21.37%±1.66% vs. 12.61%±0.38%, t=8.92, P=0.001). Furthermore, following TFDP2 knockdown, a decrease in the phosphorylation activity of catalytic subunit of protein kinase A (PKAc) at the Thr197 site was observed in the cytoplasm of BeWo cells (0.466±0.035 vs. 1.000±0.075, t=11.19, P<0.001) and a reduction in the expression of β-catenin in the cell nucleus was also detected (0.250±0.093 vs. 1.000±0.269, t=4.57, P=0.010). Conclusion:The expression of TFDP2 decreased significantly in the placentas of patients with preeclampsia, which may promote the apoptosis of syncytiotrophoblasts by inhibiting the PKAc/β-catenin signaling pathway.