Abstract
Introduction
Appropriate extravillous trophoblast (EVT) invasion is essential for successful pregnancy. Previously, we showed that EVTs express CD44, which accelerated EVT invasion. However, its regulation mechanism via CD44 remains unknown. Our hypothesis was that WNT signaling enhanced EVT invasion via CD44. To test this hypothesis, we investigated the effects of WNT ligands on CD44 expression and EVT invasion using EVT cell lines and isolated primary EVTs.
Methods
We used EVT cell lines (HTR8/SVneo and HChEpC1b) and isolated primary EVTs, extracted from first-trimester trophoblasts. The cells were supplemented with WNT3A, 5A, and 10B. We examined cell invasion and the expressions of CD44 and matrix metalloproteinase (MMP) 9. Next, to clarify the pathway of WNT10B in EVTs, we knock-downed WNT10B using siRNA and activated or inhibited the WNT canonical pathway using an activator (lithium chloride) or inhibitor (FH535, XAV939) with WNT10B addition.
Results
WNT3A, 5A, and 10B accelerated the invasion in the EVT lines and isolated primary EVTs. The expressions of CD44 and MMP9 were also upregulated by WNT ligands. WNT10B knockdown significantly inhibited EVT invasion concomitantly with CD44 expression. The WNT canonical pathway activator upregulated CD44 expression and its inhibitor downregulated it with WNT10B addition.
Conclusions
The present study is the first to show the possibility that WNT3A, WNT5A, and WNT10B exist upstream of CD44 in EVTs. Among them, WNT10B may be a novel accelerator of EVT invasion. WNT signaling mediated by multiple WNT ligands may contribute to EVT invasion.
Ethical approval
Informed consent is obtained.
Acknowledgments
We thank Takuji Kosuge (Nippon Medical School, Bunkyo-ku, Tokyo, Japan) for providing technical assistance.
Disclosure statement
No potential conflict of interest was reported by the authors.
Correction Statement
This article has been republished with minor changes. These changes do not impact the academic content of the article.