Deciphering villous and extravillous trophoblast differentiation: Participation of the Krüppel-like transcription factor 6

formato virtual

Congreso; IX SLIMP VIRTUAL MEETING; 2022

Trophoblast differentiation is a very complex process. KLF6 is a ubiquitous transcription factor with an N-terminal acidic transactivation domain and a C-terminal zinc finger DNA-binding domain. klf6-/- mice die at day E12.5 showing impaired placenta development. KLF6 expression is early upregulated during syncytialization in BeWo and primary villous trophoblast cells, and in HTR8/Svneo cells exposed to hypoxia. The aim of the present study was to analyze the participation of KLF6 in human villous and extravillous trophoblast cell differentiation.BeWo cells were transduced with lenti-virus particles to generate stable cell lines for the full-length KLF6 protein, a deletion mutant lacking its acidic domain (KLF6Δac), or the empty vector. These cell lines were treated or not with 30 μM forskolin and cell fusion was analysed by immunofluorescence. HTR8/Svneo cells were transiently silenced for KLF6 or stably transfected with the KLF6Δac construct and migration was analyzed through wound healing and transwell assays. Transcript and protein levels were measured by qRT-PCR and western blot, respectively. Cell proliferation was evaluated by BrdU labelling and cell counting assays.Results reveal that KLF6 is an inducer of villous trophoblast cell differentiation through a mechanism that involves its N-terminal domain, while KLF6 downregulation promotes HTR8/Svneo cells differentiation. The fusion index of KLF6-BeWo cells is significantly higher than that observed in the empty vector-BeWo cells accompanied by a decrease in cell proliferation. Forskolin-induced cell fusion is further increased in KLF6-BeWo cells. On the other hand, KLF6 silencing in HTR8/Svneo cells leads to increased migration together with an induction of a mesenchymal phenotype with higher levels of N-cadherin.Present results reveal that KLF6 regulates villous trophoblast differentiation and fusion, but also the extravillous differentiation into a migratory phenotype.