Peroxisome proliferator‐activated receptor gamma‐ligand‐binding domain mutations associated with familial partial lipodystrophy type 3 disrupt human trophoblast fusion and fibroblast migration

The transcription factor peroxisome proliferator‐activated receptor gamma (PPARG) is essential for placental development, and alterations in its expression and/or activity are associated with human placental pathologies such as pre‐eclampsia or IUGR. However, the molecular regulation of PPARG in cytotrophoblast differentiation and in the underlying mesenchyme remains poorly understood. Our main goal was to study the impact of mutations in the ligand‐binding domain (LBD) of the PPARG gene on cytotrophoblast fusion (PPARG(E352Q)) and on fibroblast cell migration (PPARG(R262G)/PPARG(L319X)). Our results showed that, compared to cells with reconstituted PPARG(WT), transfection with PPARG(E352Q) led to significantly lower PPARG activity and lower restoration of trophoblast fusion. Likewise, compared to PPARG(WT) fibroblasts, PPARG(R262G)/PPARG(L319X) fibroblasts demonstrated significantly inhibited cell migration. In conclusion, we report that single missense or nonsense mutations in the LBD of PPARG significantly inhibit cell fusion and migration processes.