(898) Metformin decouples biochemical and morphologic syncytialization during trophoblast differentiation

Trophoblast differentiation into syncytiotrophoblasts is impaired in pregnancies complicated by gestational diabetes. Mechanisms underlying this are unknown. Cellular differentiation in skeletal, adipose, and hematologic stem cell models is regulated by metformin. In this work, we test the hypothesis that metformin modulates trophoblast differentiation. 

Study Design:

Using established BeWo and Trophoblast Stem Cell (TSC) models, we plated and treated cells with metformin 200 uM, 2000 uM, or PBS as a vehicle control. 24 hours after plating, we treated cells with forskolin (FSK) to induce syncytialization or DMSO as a vehicle control. Western blotting for phospho-AMPK and AMPK confirmed metformin activity within cells. We assessed differentiation using ELISA for HCG and quantitative PCR (qPCR). We evaluated morphologic differences in syncytialization using confocal microscopy. After Grubbs test to exclude outliers, we used ANOVA to compare groups: we considered p < 0.05 statistically significant.

Results:

We find that treatment with metformin impairs HCG production following differentiation of BeWo and TSC and impairs expression of multiple trophoblast differentiation markers. Specifically, ELISA demonstrates a 67% decrease in HCG production following treatment with 2000 uM metformin (p < 0.0001). Following treatment with metformin, qPCR demonstrates no impact on HSD11B2 and OVOL1 expression. TEAD4 does not decrease as expected. However, metformin significantly impairs CGA, CGB, ERVW, and ERVFRD expression. Refer to the figure for representative qPCR data. These impairments in gene expression are not associated with changes in morphologic syncytialization.

Conclusion:

Our data show that metformin specifically regulates the expression of key genes during syncytialization though does not impair the formation of syncytia. This indicates that metformin decouples morphologic and biochemical syncytialization. This suggests metformin regulates trophoblast differentiation and may have broader impacts on cellular function.