Participation of ezrin in bacterial uptake by trophoblast giant cells

Mouse TG cells were employed in all experiments, and B. abortus was used as the bacterial antigen. Confirmation of the binding capacity of ERM protein was assessed by pull-down assay and ELISA using recombinant Hsc70 and ERM proteins. Ezrin was depleted using siRNA and the depletion examined by immunoblotting or immunofluorescence staining.The expression level of ezrin was higher in TG cells than in trophoblast stem (TS) cells, and ezrin knockdown TG cells showed a reduction in bacterial uptake ability. Although tyrosine phosphorylation of ezrin was not related to bacterial uptake activity, localization of Hsc70 on the membrane was affected by the depletion of ezrin in TG cells.Ezrin associates with Hsc70 that locates on the membrane of TG cells and participates in the bacterial uptake by TG cells.Trophoblast giant (TG) cells are polyploid cells differentiated from trophoblast stem (TS) cells by many morphological and functional developments; they form the fetal component of placenta [1]. In particular, TG cells play a crucial role in implantation and forming a diffuse network of blood sinuses [2], and promote maternal blood flow to the implantation site in mice [3]. TG cells are essential for establishment of pregnancy. We previously reported that Brucella abortus, an intracellular bacteria that causes abortion in pregnant animals, internalized and replicated in TG cells, specifically in pregnant mice [4]. This study suggested that internalization and replication of Brucella in TG cells play a key role in causing abortion and that TG cells are closely linked to the avoidance of maternal immune rejection.Trophoblast cells have a phagocytic ability. During implantation, trophoblast cells invade maternal tissue by phagocytosing the uterine epithelial cells and stroma [5]. Several molecular mechanisms involved in phagocytosis by trophoblast cells have been reported [6], but the complete process remains unclear. It has also been reported that trophoblast cells can phago