Fig. 7
Molecular direct interaction between FXR and ER was evaluated by Proximity Ligation Assay (PLA) in the MCF7 cell line (a). The formation of heterodimers between both receptors (ER linked to FXR) was evaluated after exposure to CDCA (2 10− 5 M) at different time laps (from 30 s to 1 h). The heterodimers appeared as red spots and the nucleus was stained in blue by DAPI. In controls without CDCA stimulation (c), a low level of ER-FXR heterodimers was evidenced. After 2 min of CDCA (2 m), the number of heterodimers increased a lot in cells and started to translocate in the nucleus at 5 min (5 m). The maximum of heterodimers in the nucleus was observed at 30 min after CDCA treatment (30 m) and decreased after 1 h of CDCA (1 h). Scale bars = 50 μm. b ER-FXR dimers quantification. For all processing times, the percentage of dimers ER-FXR increased after a CDCA treatment compared to the control. The maximum was noticed at 30 m and decreased at 1 h of treatment. Values represent the mean percentage of mean fluorescence ± SEM of four independent experiments. (*** p < 0.001, ** p < 0.01, * p < 0.05). Control values are normalized at 100%