Abstract
Normal implantation depends on appropriate trophoblast growth and invasion. Inadequate trophoblast invasion results in pregnancy-related disorders, such as early miscarriage and pre-eclampsia, which are dangerous to both the mother and fetus. Msh Homeobox 2 (MSX2), a member of the MSX family of homeobox proteins, plays a significant role in the proliferation and differentiation of various cells and tissues, including ectodermal organs, teeth, and chondrocytes. Recently, MSX2 was found to play important roles in the invasion of cancer cells into adjacent tissues via the epithelial-mesenchymal transition (EMT). However, the role of MSX2 in trophoblastic invasion during placental development has yet to be explored. In the present study, we detected MSX2 expression in cytotrophoblast, syncytiotrophoblast, and extravillous cytotrophoblast cells of first or third trimester human placentas via immunohistochemistry analysis. Furthermore, we found that the in vitro invasive ability of HTR8/SVneo cells was enhanced by exogenous overexpression of MSX2, and that this effect was accompanied by increased protein expression of matrix metalloproteinase-2 (MMP-2), vimentin, and β-catenin. Conversely, treatment of HTR8/SVneo cells with MSX2-specific siRNAs resulted in decreased protein expression of MMP-2, vimentin, and β-catenin, and reduced invasion levels in a Matrigel invasion test. Notably, however, treatment with the MSX2 overexpression plasmid and the MSX2 siRNAs had no effect on the mRNA expression levels of β-catenin. Meanwhile, overexpression of MSX2 and treatment with the MSX2-specific siRNA resulted in decreased and increased E-cadherin expression, respectively, in JEG-3 cells. Lastly, the protein expression levels of MSX2 were significantly lower in human pre-eclamptic placental villi than in the matched control placentas. Collectively, our results suggest that MSX2 may induce human trophoblast cell invasion, and dysregulation of MSX2 expression may be associated with pre-eclampsia.
Highlights
Favorable development of the embryo after implantation depends on the formation of a functional placenta
We found that the in vitro invasive ability of HTR8/SVneo cells was enhanced by exogenous overexpression of Msh Homeobox 2 (MSX2), and that this effect was accompanied by increased protein expression of matrix metalloproteinase-2 (MMP-2), vimentin, and β-catenin
We examined the expression of MSX2 in human trophoblast cell lines by western blotting MSX2 proteins were present in HTR8/SVneo cells, were high in JEG-3 cells and JAR cells, but low in BeWo cells (Fig 1C)
Summary
Favorable development of the embryo after implantation depends on the formation of a functional placenta. The growth and invasion of trophoblast cells is PLOS ONE | DOI:10.1371/journal.pone.0153656. Trophoblast progenitor cells, called cytotrophoblasts (CTB), originate from the outer layer of the blastocyst, provide nutrients for the embryo, and develop into the fetal portion of the placenta. The STB is a multinucleated monolayer located in the outer layer of the villus that comes in direct contact with the maternal blood that reaches the placental surface, and facilitates the exchange of nutrients, waste, and gases between the maternal and fetal systems. Matrix metalloproteinases (MMPs) with collagenase activity, MMP-2 and MMP-9, are important during early embryonic and placental development. The activity of MMPs in the breaching of the extracellular matrix barrier by trophoblasts during embryo implantation and early placental development. There is considerable evidence that MMPs play essential roles in trophoblast invasion at the fetalmaternal interface [7, 8]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
