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

ANDREA MIRANDA; LUCILE KOURDOVA; RACCA, ANA C.; CRUZ DEL PUERTO, MARIANO; GENTI DE RAIMONDI SUSANA; GRACIELA PANZETTA DE DUTARI

Congreso; Reunión Conjunta SAIC SAI SAFIS 2018; 2018

Sociedad Argentina de Investigación Clínica

Proper placenta development is critical for foetal well-being andpregnancy outcome. Trophoblasts differentiate into the multinucleatedsyncytiotrophoblast and the migratory/invasive cytotrophoblasts,through the villous and extravillous pathways, respectively. KLF6 isa ubiquitous transcription factor highly expressed in placenta. Klf6-/-mice die at day E12.5 showing impaired placenta development. Wehave demonstrated that KLF6 is required for cell?cell fusion in humanprimary villous cytotrophoblast as well as in the BeWo trophoblast-derived cell line. Additionally, KLF6 immunoreactivity is higherin the placental bed of preeclamptic than in those of uncomplicatedpregnancies. We hypothesize that KLF6 is a key transcription factorinvolved in both differentiation pathways. Cell-cell fusion was analysedby immunofluorescence in BeWo cells overexpressing or notKLF6 and treated or not with 30 μM forskolin, an inducer of BeWofusion. Migration was evaluated through wound-healing and transwellassays inHTR8/SVneo extravillous cells transfected with aspecific KLF6 siRNA or control scramble siRNA. Cell proliferationand viability was evaluated by BrdU labelling, MTT assay and cellcount. Transcript and/or protein level of differentiation markers wereevaluated by RT-PCR and western blot, respectively. The syncytializationindex, as well as βhCG, syncytin-1 and p21 expression werestatistically significantly higher in cells overexpressing KLF6, even inthe absence of forskolin treatment. On the other hand, increased migrationand expression of β-catenin and connexin-43 was observedin HTR8/SVneo KLF6-silenced cells, whereas proliferation wasreduced. Present results reveal that KLF6 can initiate and induceBeWo cell fusion and syncytiotrophoblast genes expression, suggestingthat it is a master regulatory gene of cell differentiation intosyncytium. While the enhanced migratory capacity of KLF6-silencedHTR8/SVneo cells and the increased KLF6 immunoreactivity detectedin the placental bed of preeclamptic pregnancies characterizedby impaired cytotrophoblast invasion into the decidua, suggest thatKLF6 modulates trophoblast differentiation into the extravillous invasivepathway.