Nitric oxide (NO) reversed TNF-α inhibition of trophoblast interaction with endothelial cellular networks

Introduction. The interaction between trophoblast cells and maternal uterine endothelium is important for placental vascular modelling. Nitric oxide (NO) is a potent vasorelaxant that regulates systemic blood pressure and is reduced in preeclampsia. NO may affect placental cell interaction. Objectives. This study was to examine whether NO plays a role in regulating TNF-α induced inhibition of trophoblast cell integration into endothelial cellular networks in-vitro. Methods. Red fluorescent-labelled human uterine myometrial microvascular endothelial cells (UtMVECs) were seeded on Matrigel. After endothelial cellular networks formed, green fluorescent-labelled HTR-8/SVneo trophoblast cells were co-cultured with endothelial cells, together with/without TNF-α (0.5 ng/ml) and/or NO donor, sodium nitroprusside dihydrate (SNP) (100 μM). Images were captured after 24 h. The effects on HTR-8/SVneo cell integration were quantified by Image Analysis software. The cells were then recovered from Matrigel to extract mRNA. Quantitative PCR was performed to evaluate the expression of eNOS, VCAM-1 and E-selectin. The concentrations of sVCAM-1 and sE-selectin in the conditioned medium were measured by ELISA. Results. TNF-α inhibited HTR-8/SVneo trophoblast cell integration into endothelial cellular networks, as well as decreased eNOS mRNA expression. Increases in VCAM-1 and E-selectin in cellular mRNA and protein concentrations in the conditioned medium were also seen. The NO donor reversed the inhibitory effect of TNF-α on trophoblast integration and increased eNOS mRNA expression. SNP also reduced sE-selectin and sVCAM-1 expressions which were increased by TNF-α in the conditioned medium. Conclusion. Our data suggest the inhibitory effect of TNF-α on trophoblast integration may be mediated by NO, via reducing endothelial cell activation.