Divalent metal transporter 1 expression and regulation in human placenta

Divalent metal transporter 1 (DMT1) is likely responsible for the release of iron from endosomes to the cytoplasm in placental syncytiotrophoblasts (STB). To determine the localization and the regulation of DMT1 expression by iron directly in placenta, the expression of DMT1 in human term placental tissues and BeWo cells (human placental choriocarcinoma cell line) was detected and the change in expression in response to different iron treatments on BeWo cells was observed. DMT1 was shown to be most prominent near the maternal side in human term placenta and predominantly in the cytoplasm of BeWo cells. BeWo cells were treated with desferrioxamine (DFO) and human holotransferrin (hTf-2Fe) and it was found that both DMT1 mRNA and protein increased significantly with DFO treatment and decreased with hTf-2Fe treatment. Further, DMT1 mRNA responded more significantly to treatments if it possessed an iron-responsive element than mRNA without this element. This study indicated that DMT1 is likely involved in endosomal iron transport in placental STB and placental DMT1 + IRE expression was primarily regulated by the IRE/IRP mechanism.