KRÜPPLE-LIKE TRANSCRIPTION FACTOR 6 (KLF6) TRIGGERS PLACENTAL TROPHOBLAST CELL FUSION AND MODULATES CELL MIGRATION

MIRANDA, ANDREA L; ROJAS, MARIA L.; PANZETTA-DUTARI, G.M.; RACCA, ANA C.; GENTI-RAIMONDI, S.; KOURDOVA, LUCILLE T; CRUZ DEL PUERTO, MARIANO

Mar del Plata

Congreso; SAIC SAI SAFIS 2018; 2018

Proper placenta development is critical for foetal well-being and pregnancy outcome. Trophoblasts differentiate into the multinucleated syncytiotrophoblast and the migratory/invasive cytotrophoblasts, through the villous and extravillous pathways, respectively. KLF6 is a ubiquitous transcription factor highly expressed in placenta. Klf6-/- mice die at day E12.5 showing impaired placenta development. We have demonstrated that KLF6 is required for cell?cell fusion in human primary villous cytotrophoblast as well as in the BeWo trophoblast-derived cell line. Additionally, KLF6 immunoreactivity is higher in the placental bed of preeclamptic than in those of uncomplicated pregnancies. We hypothesize that KLF6 is a key transcription factor involved in both differentiation pathways. Cell-cell fusion was analysed by immunofluorescence in BeWo cells overexpressing or not KLF6 and treated or not with 30 µM forskolin, an inducer of BeWo fusion. Migration was evaluated through wound-healing and transwell assays inHTR8/SVneo extravillous cells transfected with a specific KLF6 siRNA or control scramble siRNA. Cell proliferation and viability was evaluated by BrdU labelling, MTT assay and cell count. Transcript and/or protein level of differentiation markers were evaluated by RT-PCR and western blot, respectively. The syncytialization index, as well as βhCG, syncytin-1 and p21 expression were statistically significantly higher in cells overexpressing KLF6, even in the absence of forskolin treatment. On the other hand, increased migration and expression of β-catenin and connexin-43 was observed in HTR8/SVneo KLF6-silenced cells, whereas proliferation was reduced. Present results reveal that KLF6 can initiate and induce BeWo cell fusion and syncytiotrophoblast genes expression, suggesting that it is a master regulatory gene of cell differentiation into syncytium. While the enhanced migratory capacity of KLF6-silenced HTR8/SVneo cells and the increased KLF6 immunoreactivity detected in the placental bed of preeclamptic pregnancies characterized by impaired cytotrophoblast invasion into the decidua, suggest that KLF6 modulates trophoblast differentiation into the extravillous invasive pathway.