Effects of SLC7A2 gene overexpression on trophoblast cell proliferation and migration in the placenta of pigs with intrauterine growth retardation

【Objective】 This study aimed to investigate the expression differences of solute carrier family 7 member 2 gene（SLC7A2） in the placentas of normal birth weight（NBW） piglets and intrauterine growth retardation（IUGR） piglets, and determine the effect of SCL7A2 gene overexpression on the proliferation and migration of trophoblast cells（p Tr2） to provide a reference for revealing the occurrence and development mechanism of IUGR in pigs. 【Method】 Realtime fluorescence quantitative PCR（RT-qPCR） was used to detect the relative expression of SLC7A2 gene in NBW and IUGR placentas. The localization, distribution and expression level of SLC7A2 protein in placental tissues of NBW and IUGR were analyzed by immunohistochemistry. The effects of SLC7A2 gene overexpression on the proliferation were detected by CCK-8 assay, effects of SLC7A2 gene overexpression on migration ability of pTr2 cells were detected by cell scratch assay. 【Result】 The relative expression of SLC7A2 gene in IUGR placentas was extremely significantly higher（P＜0.01, the same bellow） than that in NBW placentas. SLC7A2 protein was expressed in both trophoblast cells and vascular endothelial cells in pig placentas, with a significantly higher expression level in IUGR placentas compared to NBW placentas（P＜0.05, the same bellow）. The constructed SLC7A2 gene overexpression vector（Vector-SLC7A2⁺） was transfected into pTr2 cells, resulting in an extremely significant up-regulation of the relative expression of SLC7A2 gene in the cells compared to the pEGFP-C1 negative control vector（Vector-NC） transfected group. However, there was no significant difference in the relative expression of pEGFP-C1 between the two groups（P＞0.05）. After transfection of pTr2 cells with Vector-SLC7A2⁺ and Vector-NC respectively, the proliferation of pTr2 cells in the Vector-SLC7A2⁺ transfected group was significantly or extremely significantly lower than that in the Vector-NC transfected group at 12, 24, 48, and 72 h post-transfection. Similarly, the migration rate of pTr2 cells in the Vector-SLC7A2⁺ transfected group was extremely significantly lower than that in the Vector-NC transfected group, demonstrating that SLC7A2 gene overexpression could effectively inhibit proliferation and migration capabilities of pTr2 cells. 【Conclusion】 Overexpression of the SLC7A2 gene can inhibit the proliferation and migration of porcine placental trophoblast cells, affecting placental morphological development and maternal-fetal nutrient transport efficiency, and ultimately contributing to the occurrence and development of IUGR in pigs.