Unveiling the role of microRNA‐7 in linking TGF‐β‐Smad‐mediated epithelial‐mesenchymal transition with negative regulation of trophoblast invasion

What is it about?

Severe pregnancy complications can lead to suffer or even the death of women and those complications may result from abnormal trophoblast invasion. The trophoblast invasion must be well regulated to control the invasion depth of placenta, which too few or too many invasion may lead to various complications, such as fetal growth restriction or preeclampsia. Trophoblasts share some characteristics with cancer cells, including rapid growth and invasion. Trophoblast invasion usually links to TGF-b, which also regulates the migration and invasion of cancer. However, TGF-b facilitates cancer metastasis while it inhibits trophoblast invasion. The mechanisms underlying the controversial of TGF-b regulation in trophoblast and cancers remain unclear and there are no good markers for indicating these pregnancy complications. This study found a new mechanism of miRNA, miR-7, exerting an inhibiting effect on trophoblast invasion, such as putting the brake on trophoblast invasion. miR-7 expression is delicately controlled by TGFb-receptor and Smad2, and it also regulates the expression of transcription factors of epithelial-mesenchymal transition (EMT), which is the initiation step of cell invasion. The expression level of miR-7 also links to pregnancy complications, including placenta previa, placenta previa accrete, and preeclampsia, thus miR-7 may become a new marker for indicating pregnancy complications.

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