Krüppel-like transcription factor 6 (KLF6) triggers placental trophoblast cell fusion and modulates cell migration

MIRANDA AL; KOURDOVA LT; RACCA AC; CRUZ DEL PUERTO MMA; ROJAS ML; GENTI DE RAIMONDI S; PANZETTA DE DUTARI G.

Congreso; LXIII Reunión Anual de la Sociedad Argentina de Investigación Clínica; 2018

SAIC. SAI. SAFIS

Proper placenta development is critical for foetal well-being and pregnancy outcome. Trophoblasts differentiate into the multinucleatedsyncytiotrophoblast and the migratory/invasive cytotrophoblasts, through the villous and extravillous pathways, respectively. KLF6 is aubiquitous transcription factor highly expressed in placenta. Klf6-/- mice die at day E12.5 showing impaired placenta development. We havedemonstrated that KLF6 is required for cell?cell fusion in human primary villous cytotrophoblast as well as in the BeWo trophoblast-derivedcell line. Additionally, KLF6 immunoreactivity is higher in the placental bed of preeclamptic than in those of uncomplicated pregnancies. Wehypothesize that KLF6 is a key transcription factor involved in both differentiation pathways. Cell-cell fusion was analysed byimmunofluorescence 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 in HTR8/SVneo extravillous cells transfected with a specific KLF6siRNA or control scramble siRNA. Cell proliferation and viability was evaluated by BrdU labelling, MTT assay and cell count. Transcriptand/or protein level of differentiation markers were evaluated by RT-PCR and western blot, respectively. The syncytialization index, as well asβhCG, syncytin-1 and p21 expression were statistically significantly higher in cells overexpressing KLF6, even in the absence of forskolintreatment. On the other hand, increased migration and expression of β-catenin and connexin-43 was observed in HTR8/SVneo KLF6-silencedcells, whereas proliferation was reduced. Present results reveal that KLF6 can initiate and induce BeWo cell fusion and syncytiotrophoblastgenes expression, suggesting that it is a master regulatory gene of cell differentiation into syncytium. While the enhanced migratory capacityof KLF6-silenced HTR8/SVneo cells and the increased KLF6 immunoreactivity detected in the placental bed of preeclamptic pregnanciescharacterized by impaired cytotrophoblast invasion into the decidua, suggest that KLF6 modulates trophoblast differentiation into theextravillous invasive pathway