Gal-1 silenced trophoblast tumour cells (BeWo) show decreased syncytium formation and different miRNA production compared to non-target silenced BeWo cells

Gestational pathologies such as preeclampsia, HELLP syndrome and intrauterine growth restriction are partly based on insufficient placentation. Adequate syncytium formation is an important precondition and part of placentation. Gal-1 induces cell differentiation processes on the membrane of choriocarcinoma cells BeWo, including the receptor tyrosine kinases (RTKs) REarranged during Transfection (RET), Janus Kinase 2 (JAK2) and Vascular endothelial growth factor receptor 3 (VEGFR3).

The syncytium formation abilities of BeWo cells that were gal-1 silenced were analyzed using immunohistochemistry and immunofluorescence. Cell fusion was shown by using cell labeling and quantification of β-Catenin and E-cadherin both being marker for syncytium formation. Quantitative Real Time PCR was used to show miRNA expression in gal-1 silenced BeWo cell culture.

A significantly reduced syncytium formation rate in gal-1 silenced BeWo cells was found. In addition, these cells show a different miRNA expression profile. After fusion of cells significantly higher numbers of fused cells were seen in control BeWo cells compared to gal-1 silenced cells. In immunofluorescence syncytin protein expression was significantly increased from gal-1 silenced BeWo cells to control BeWo cells.

In summary, we found that gal-1 is a major trigger for fusion processes in BeWo cells. This function is accompanied by different regulation of miRNA synthesis in the BeWo cell culture model.